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* [PATCH v7 00/25] Rust support
@ 2022-05-23  2:01 Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size Miguel Ojeda
                   ` (21 more replies)
  0 siblings, 22 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	kunit-dev, linux-arm-kernel, linux-doc, linux-gpio, linux-kbuild,
	linux-kselftest, linux-perf-users, linuxppc-dev, linux-riscv,
	linux-um, live-patching

Rust support

This is the patch series (v7) to add support for Rust as a second
language to the Linux kernel.

If you are interested in following this effort, please join us in
the mailing list at:

    rust-for-linux@vger.kernel.org

and take a look at the project itself at:

    https://github.com/Rust-for-Linux

As usual, special thanks go to ISRG (Internet Security Research
Group) and Google for their financial support on this endeavor.

Cheers,
Miguel

--

# Rust support

This cover letter explains the major changes and updates done since
the previous ones. For those, please see:

    RFC: https://lore.kernel.org/lkml/20210414184604.23473-1-ojeda@kernel.org/
    v1:  https://lore.kernel.org/lkml/20210704202756.29107-1-ojeda@kernel.org/
    v2:  https://lore.kernel.org/lkml/20211206140313.5653-1-ojeda@kernel.org/
    v3:  https://lore.kernel.org/lkml/20220117053349.6804-1-ojeda@kernel.org/
    v4:  https://lore.kernel.org/lkml/20220212130410.6901-1-ojeda@kernel.org/
    v5:  https://lore.kernel.org/lkml/20220317181032.15436-1-ojeda@kernel.org/
    v6:  https://lore.kernel.org/lkml/20220507052451.12890-1-ojeda@kernel.org/

This is a small round to address the comments made in v6 plus a few
related changes:

  - Added `%pA` to `Documentation/core-api/printk-formats.rst`.

  - Added `checkpatch.pl` patch to search for `%pA` in C code.

  - Added `checkpatch.pl` patch to enable language-independent checks.

  - Added UML (x86_64) support, for KUnit (thanks David Gow!).

  - Added inline licensing information ("Apache-2.0 OR MIT") in
    the commit message of the `alloc` patch, as well as in
    `rust/alloc/README.md` in the following patch.

  - Added SPDX license identifiers to `Documentation/rust/`.

  - Reformatted `Documentation/rust/arch-support.rst` list table
    into simple table.

  - Removed logo from documentation patch; used Linux GIF one for
    the Rust generated docs in its place (to be replaced with
    the SVG one once available).

  - Used `"GPL"` instead of `"GPL v2"` for the `license` field of the
    `module!` macro.

  - Moved `module_misc_device!` macro in `samples/rust/rust_random.rs`
    to the top of the file in `samples/rust/` for consistency.

  - Sorted `#include` lists in `rust/kernel/bindings_helper.h`
    and `rust/helpers.c`.

  - Fixed some English typos.

  - Made the patches more `checkpatch.pl`-clean overall.

  - Picked up Reviewed-by and Acked-by tags.


## Patch series status

The Rust support is still to be considered experimental. However,
support is good enough that kernel developers can start working on the
Rust abstractions for subsystems and write drivers and other modules.

The current series has just arrived in `linux-next`, as usual.
Similarly, the preview docs for this series can be seen at:

    https://rust-for-linux.github.io/docs/kernel/

As usual, please see the following link for the live list of unstable
Rust features we are using:

    https://github.com/Rust-for-Linux/linux/issues/2


## Conferences, meetings and liaisons

We would like to remind everyone about the Rust MC (microconference)
of LPC 2022 (Linux Plumbers Conference):

    https://lpc.events/event/16/contributions/1159/

The Rust MC intends to cover talks and discussions on both Rust for
Linux as well as other non-kernel Rust topics. The Call for Proposals
is open!


## Acknowledgements

The signatures in the main commits correspond to the people that
wrote code that has ended up in them at the present time. For details
on contributions to code and discussions, please see our repository:

    https://github.com/Rust-for-Linux/linux

However, we would like to give credit to everyone that has contributed
in one way or another to the Rust for Linux project. Since the
previous cover letter:

  - Kees Cook for his reviews of some of the v6 patches.

  - David Gow and Brendan Higgins for their reviews of the KUnit
    prerequisite patch and their feedback.

  - Jonathan Corbet and Akira Yokosawa for their review of the
    documentation patch and feedback on documentation rules.

  - Gary Guo for working on improvements to the Rust compiler that
    could make our `static_assert!` macro applicable in more cases.

  - bjorn3 for working on making `rustc_parse_format` compile on
    a stable Rust compiler so that it may be used by lightweight
    formatting systems (for instance, by the kernel).

  - As usual, bjorn3 and Gary Guo for all the input on Rust compiler
    details, reviews and suggestions.

  - Esteban Blanc, Arthur Cohen and Martin Schmidt for rebasing their
    SPI abstraction work.

  - Maciej Falkowski for continuing his work on the Samsung Exynos
    TRNG driver and the required abstractions around it, such as
    adding `delay`, `ktime` and `iopoll` abstractions, new methods
    to `platform::Device` and run-time power management abstractions.

  - Yuheng Su for working on cleaning up the `Module::init` interface.

  - Peng Hao for working on wrapping `mm_struct`.

  - Sergio González Collado for continuing his work on the GitHub CI
    problem matchers.

  - Wei Liu for taking the time to answer questions from newcomers
    in Zulip.

  - Philip Li, Yujie Liu et al. for continuing their work on adding
    Rust support to the Intel 0DAY/LKP kernel test robot.

  - Philip Herron and Arthur Cohen (and his supporters Open Source
    Security and Embecosm) et al. for their ongoing work on GCC Rust.

  - Antoni Boucher (and his supporters) et al. for their ongoing
    work on `rustc_codegen_gcc`.

  - Mats Larsen, Marc Poulhiès et al. for their ongoing work on
    improving Rust support in Compiler Explorer.

  - Many folks that have reported issues, tested the project,
    helped spread the word, joined discussions and contributed in
    other ways!

Please see also the acknowledgements on the previous cover letters.


Boqun Feng (1):
  kallsyms: avoid hardcoding the buffer size

Gary Guo (2):
  rust: add `build_error` crate
  vsprintf: add new `%pA` format specifier

Miguel Ojeda (18):
  kallsyms: support "big" kernel symbols
  kallsyms: increase maximum kernel symbol length to 512
  kunit: take `kunit_assert` as `const`
  rust: add C helpers
  rust: add `compiler_builtins` crate
  rust: import upstream `alloc` crate
  rust: adapt `alloc` crate to the kernel
  rust: add `macros` crate
  rust: export generated symbols
  scripts: checkpatch: diagnose uses of `%pA` in the C side
  scripts: checkpatch: enable language-independent checks for Rust
  scripts: add `rustdoc_test_{builder,gen}.py` scripts
  scripts: add `generate_rust_analyzer.py` scripts
  scripts: decode_stacktrace: demangle Rust symbols
  docs: add Rust documentation
  Kbuild: add Rust support
  samples: add Rust examples
  MAINTAINERS: Rust

Wedson Almeida Filho (4):
  rust: add `kernel` crate's `sync` module
  rust: add `kernel` crate
  [RFC] drivers: gpio: PrimeCell PL061 in Rust
  [RFC] drivers: android: Binder IPC in Rust

 .gitignore                                   |    5 +
 .rustfmt.toml                                |   12 +
 Documentation/core-api/printk-formats.rst    |   10 +
 Documentation/doc-guide/kernel-doc.rst       |    3 +
 Documentation/index.rst                      |    1 +
 Documentation/kbuild/kbuild.rst              |   17 +
 Documentation/kbuild/makefiles.rst           |   50 +-
 Documentation/process/changes.rst            |   41 +
 Documentation/rust/arch-support.rst          |   25 +
 Documentation/rust/coding-guidelines.rst     |  216 ++
 Documentation/rust/general-information.rst   |   79 +
 Documentation/rust/index.rst                 |   22 +
 Documentation/rust/quick-start.rst           |  232 ++
 MAINTAINERS                                  |   15 +
 Makefile                                     |  175 +-
 arch/Kconfig                                 |    6 +
 arch/arm/Kconfig                             |    1 +
 arch/arm64/Kconfig                           |    1 +
 arch/powerpc/Kconfig                         |    1 +
 arch/riscv/Kconfig                           |    1 +
 arch/riscv/Makefile                          |    5 +
 arch/um/Kconfig                              |    1 +
 arch/x86/Kconfig                             |    1 +
 arch/x86/Makefile                            |   14 +
 drivers/android/Kconfig                      |    6 +
 drivers/android/Makefile                     |    2 +
 drivers/android/allocation.rs                |  266 ++
 drivers/android/context.rs                   |   80 +
 drivers/android/defs.rs                      |   99 +
 drivers/android/node.rs                      |  476 +++
 drivers/android/process.rs                   |  960 +++++
 drivers/android/range_alloc.rs               |  189 +
 drivers/android/rust_binder.rs               |  111 +
 drivers/android/thread.rs                    |  870 +++++
 drivers/android/transaction.rs               |  326 ++
 drivers/gpio/Kconfig                         |    8 +
 drivers/gpio/Makefile                        |    1 +
 drivers/gpio/gpio_pl061_rust.rs              |  370 ++
 include/kunit/test.h                         |    2 +-
 include/linux/kallsyms.h                     |    2 +-
 include/linux/spinlock.h                     |   25 +-
 include/uapi/linux/android/binder.h          |   28 +-
 init/Kconfig                                 |   45 +-
 kernel/kallsyms.c                            |   26 +-
 kernel/livepatch/core.c                      |    4 +-
 lib/Kconfig.debug                            |  155 +
 lib/kunit/test.c                             |    4 +-
 lib/vsprintf.c                               |   13 +
 rust/.gitignore                              |   10 +
 rust/Makefile                                |  398 +++
 rust/alloc/README.md                         |   33 +
 rust/alloc/alloc.rs                          |  438 +++
 rust/alloc/borrow.rs                         |  498 +++
 rust/alloc/boxed.rs                          | 2007 +++++++++++
 rust/alloc/collections/mod.rs                |  156 +
 rust/alloc/fmt.rs                            |  601 ++++
 rust/alloc/lib.rs                            |  226 ++
 rust/alloc/macros.rs                         |  127 +
 rust/alloc/raw_vec.rs                        |  567 +++
 rust/alloc/slice.rs                          | 1282 +++++++
 rust/alloc/str.rs                            |  632 ++++
 rust/alloc/string.rs                         | 2869 +++++++++++++++
 rust/alloc/vec/drain.rs                      |  186 +
 rust/alloc/vec/drain_filter.rs               |  145 +
 rust/alloc/vec/into_iter.rs                  |  356 ++
 rust/alloc/vec/is_zero.rs                    |  106 +
 rust/alloc/vec/mod.rs                        | 3362 ++++++++++++++++++
 rust/alloc/vec/partial_eq.rs                 |   49 +
 rust/alloc/vec/set_len_on_drop.rs            |   30 +
 rust/alloc/vec/spec_extend.rs                |  174 +
 rust/bindgen_parameters                      |   17 +
 rust/build_error.rs                          |   29 +
 rust/compiler_builtins.rs                    |   57 +
 rust/exports.c                               |   20 +
 rust/helpers.c                               |  644 ++++
 rust/kernel/allocator.rs                     |   65 +
 rust/kernel/amba.rs                          |  257 ++
 rust/kernel/bindings.rs                      |   47 +
 rust/kernel/bindings_helper.h                |   46 +
 rust/kernel/build_assert.rs                  |   82 +
 rust/kernel/c_types.rs                       |  119 +
 rust/kernel/chrdev.rs                        |  207 ++
 rust/kernel/clk.rs                           |   79 +
 rust/kernel/cred.rs                          |   46 +
 rust/kernel/device.rs                        |  546 +++
 rust/kernel/driver.rs                        |  442 +++
 rust/kernel/error.rs                         |  565 +++
 rust/kernel/file.rs                          |  860 +++++
 rust/kernel/gpio.rs                          |  478 +++
 rust/kernel/hwrng.rs                         |  242 ++
 rust/kernel/io_buffer.rs                     |  153 +
 rust/kernel/io_mem.rs                        |  275 ++
 rust/kernel/iov_iter.rs                      |   81 +
 rust/kernel/irq.rs                           |  411 +++
 rust/kernel/kasync.rs                        |    6 +
 rust/kernel/kasync/net.rs                    |  322 ++
 rust/kernel/kunit.rs                         |   91 +
 rust/kernel/lib.rs                           |  261 ++
 rust/kernel/linked_list.rs                   |  247 ++
 rust/kernel/miscdev.rs                       |  291 ++
 rust/kernel/mm.rs                            |  149 +
 rust/kernel/module_param.rs                  |  498 +++
 rust/kernel/net.rs                           |  392 ++
 rust/kernel/net/filter.rs                    |  447 +++
 rust/kernel/of.rs                            |   63 +
 rust/kernel/pages.rs                         |  144 +
 rust/kernel/platform.rs                      |  223 ++
 rust/kernel/power.rs                         |  118 +
 rust/kernel/prelude.rs                       |   36 +
 rust/kernel/print.rs                         |  405 +++
 rust/kernel/random.rs                        |   42 +
 rust/kernel/raw_list.rs                      |  361 ++
 rust/kernel/rbtree.rs                        |  563 +++
 rust/kernel/revocable.rs                     |  161 +
 rust/kernel/security.rs                      |   38 +
 rust/kernel/static_assert.rs                 |   38 +
 rust/kernel/std_vendor.rs                    |  160 +
 rust/kernel/str.rs                           |  597 ++++
 rust/kernel/sync.rs                          |  161 +
 rust/kernel/sync/arc.rs                      |  503 +++
 rust/kernel/sync/condvar.rs                  |  138 +
 rust/kernel/sync/guard.rs                    |  169 +
 rust/kernel/sync/locked_by.rs                |  111 +
 rust/kernel/sync/mutex.rs                    |  153 +
 rust/kernel/sync/nowait.rs                   |  188 +
 rust/kernel/sync/revocable.rs                |  250 ++
 rust/kernel/sync/rwsem.rs                    |  197 +
 rust/kernel/sync/seqlock.rs                  |  202 ++
 rust/kernel/sync/smutex.rs                   |  295 ++
 rust/kernel/sync/spinlock.rs                 |  360 ++
 rust/kernel/sysctl.rs                        |  199 ++
 rust/kernel/task.rs                          |  175 +
 rust/kernel/types.rs                         |  679 ++++
 rust/kernel/user_ptr.rs                      |  175 +
 rust/macros/helpers.rs                       |   79 +
 rust/macros/lib.rs                           |   94 +
 rust/macros/module.rs                        |  631 ++++
 samples/Kconfig                              |    2 +
 samples/Makefile                             |    1 +
 samples/rust/Kconfig                         |  140 +
 samples/rust/Makefile                        |   16 +
 samples/rust/hostprogs/.gitignore            |    3 +
 samples/rust/hostprogs/Makefile              |    5 +
 samples/rust/hostprogs/a.rs                  |    7 +
 samples/rust/hostprogs/b.rs                  |    5 +
 samples/rust/hostprogs/single.rs             |   12 +
 samples/rust/rust_chrdev.rs                  |   50 +
 samples/rust/rust_minimal.rs                 |   35 +
 samples/rust/rust_miscdev.rs                 |  143 +
 samples/rust/rust_module_parameters.rs       |   69 +
 samples/rust/rust_netfilter.rs               |   54 +
 samples/rust/rust_platform.rs                |   22 +
 samples/rust/rust_print.rs                   |   54 +
 samples/rust/rust_random.rs                  |   60 +
 samples/rust/rust_semaphore.rs               |  171 +
 samples/rust/rust_semaphore_c.c              |  212 ++
 samples/rust/rust_stack_probing.rs           |   36 +
 samples/rust/rust_sync.rs                    |   93 +
 scripts/.gitignore                           |    1 +
 scripts/Kconfig.include                      |    6 +-
 scripts/Makefile                             |    3 +
 scripts/Makefile.build                       |   60 +
 scripts/Makefile.debug                       |   10 +
 scripts/Makefile.host                        |   34 +-
 scripts/Makefile.lib                         |   12 +
 scripts/Makefile.modfinal                    |    8 +-
 scripts/cc-version.sh                        |   12 +-
 scripts/checkpatch.pl                        |    8 +-
 scripts/decode_stacktrace.sh                 |   14 +
 scripts/generate_rust_analyzer.py            |  134 +
 scripts/generate_rust_target.rs              |  227 ++
 scripts/is_rust_module.sh                    |   13 +
 scripts/kallsyms.c                           |   47 +-
 scripts/kconfig/confdata.c                   |   75 +
 scripts/min-tool-version.sh                  |    6 +
 scripts/rust-is-available-bindgen-libclang.h |    2 +
 scripts/rust-is-available.sh                 |  158 +
 scripts/rustdoc_test_builder.py              |   59 +
 scripts/rustdoc_test_gen.py                  |  164 +
 tools/include/linux/kallsyms.h               |    2 +-
 tools/lib/perf/include/perf/event.h          |    2 +-
 tools/lib/symbol/kallsyms.h                  |    2 +-
 182 files changed, 37614 insertions(+), 69 deletions(-)
 create mode 100644 .rustfmt.toml
 create mode 100644 Documentation/rust/arch-support.rst
 create mode 100644 Documentation/rust/coding-guidelines.rst
 create mode 100644 Documentation/rust/general-information.rst
 create mode 100644 Documentation/rust/index.rst
 create mode 100644 Documentation/rust/quick-start.rst
 create mode 100644 drivers/android/allocation.rs
 create mode 100644 drivers/android/context.rs
 create mode 100644 drivers/android/defs.rs
 create mode 100644 drivers/android/node.rs
 create mode 100644 drivers/android/process.rs
 create mode 100644 drivers/android/range_alloc.rs
 create mode 100644 drivers/android/rust_binder.rs
 create mode 100644 drivers/android/thread.rs
 create mode 100644 drivers/android/transaction.rs
 create mode 100644 drivers/gpio/gpio_pl061_rust.rs
 create mode 100644 rust/.gitignore
 create mode 100644 rust/Makefile
 create mode 100644 rust/alloc/README.md
 create mode 100644 rust/alloc/alloc.rs
 create mode 100644 rust/alloc/borrow.rs
 create mode 100644 rust/alloc/boxed.rs
 create mode 100644 rust/alloc/collections/mod.rs
 create mode 100644 rust/alloc/fmt.rs
 create mode 100644 rust/alloc/lib.rs
 create mode 100644 rust/alloc/macros.rs
 create mode 100644 rust/alloc/raw_vec.rs
 create mode 100644 rust/alloc/slice.rs
 create mode 100644 rust/alloc/str.rs
 create mode 100644 rust/alloc/string.rs
 create mode 100644 rust/alloc/vec/drain.rs
 create mode 100644 rust/alloc/vec/drain_filter.rs
 create mode 100644 rust/alloc/vec/into_iter.rs
 create mode 100644 rust/alloc/vec/is_zero.rs
 create mode 100644 rust/alloc/vec/mod.rs
 create mode 100644 rust/alloc/vec/partial_eq.rs
 create mode 100644 rust/alloc/vec/set_len_on_drop.rs
 create mode 100644 rust/alloc/vec/spec_extend.rs
 create mode 100644 rust/bindgen_parameters
 create mode 100644 rust/build_error.rs
 create mode 100644 rust/compiler_builtins.rs
 create mode 100644 rust/exports.c
 create mode 100644 rust/helpers.c
 create mode 100644 rust/kernel/allocator.rs
 create mode 100644 rust/kernel/amba.rs
 create mode 100644 rust/kernel/bindings.rs
 create mode 100644 rust/kernel/bindings_helper.h
 create mode 100644 rust/kernel/build_assert.rs
 create mode 100644 rust/kernel/c_types.rs
 create mode 100644 rust/kernel/chrdev.rs
 create mode 100644 rust/kernel/clk.rs
 create mode 100644 rust/kernel/cred.rs
 create mode 100644 rust/kernel/device.rs
 create mode 100644 rust/kernel/driver.rs
 create mode 100644 rust/kernel/error.rs
 create mode 100644 rust/kernel/file.rs
 create mode 100644 rust/kernel/gpio.rs
 create mode 100644 rust/kernel/hwrng.rs
 create mode 100644 rust/kernel/io_buffer.rs
 create mode 100644 rust/kernel/io_mem.rs
 create mode 100644 rust/kernel/iov_iter.rs
 create mode 100644 rust/kernel/irq.rs
 create mode 100644 rust/kernel/kasync.rs
 create mode 100644 rust/kernel/kasync/net.rs
 create mode 100644 rust/kernel/kunit.rs
 create mode 100644 rust/kernel/lib.rs
 create mode 100644 rust/kernel/linked_list.rs
 create mode 100644 rust/kernel/miscdev.rs
 create mode 100644 rust/kernel/mm.rs
 create mode 100644 rust/kernel/module_param.rs
 create mode 100644 rust/kernel/net.rs
 create mode 100644 rust/kernel/net/filter.rs
 create mode 100644 rust/kernel/of.rs
 create mode 100644 rust/kernel/pages.rs
 create mode 100644 rust/kernel/platform.rs
 create mode 100644 rust/kernel/power.rs
 create mode 100644 rust/kernel/prelude.rs
 create mode 100644 rust/kernel/print.rs
 create mode 100644 rust/kernel/random.rs
 create mode 100644 rust/kernel/raw_list.rs
 create mode 100644 rust/kernel/rbtree.rs
 create mode 100644 rust/kernel/revocable.rs
 create mode 100644 rust/kernel/security.rs
 create mode 100644 rust/kernel/static_assert.rs
 create mode 100644 rust/kernel/std_vendor.rs
 create mode 100644 rust/kernel/str.rs
 create mode 100644 rust/kernel/sync.rs
 create mode 100644 rust/kernel/sync/arc.rs
 create mode 100644 rust/kernel/sync/condvar.rs
 create mode 100644 rust/kernel/sync/guard.rs
 create mode 100644 rust/kernel/sync/locked_by.rs
 create mode 100644 rust/kernel/sync/mutex.rs
 create mode 100644 rust/kernel/sync/nowait.rs
 create mode 100644 rust/kernel/sync/revocable.rs
 create mode 100644 rust/kernel/sync/rwsem.rs
 create mode 100644 rust/kernel/sync/seqlock.rs
 create mode 100644 rust/kernel/sync/smutex.rs
 create mode 100644 rust/kernel/sync/spinlock.rs
 create mode 100644 rust/kernel/sysctl.rs
 create mode 100644 rust/kernel/task.rs
 create mode 100644 rust/kernel/types.rs
 create mode 100644 rust/kernel/user_ptr.rs
 create mode 100644 rust/macros/helpers.rs
 create mode 100644 rust/macros/lib.rs
 create mode 100644 rust/macros/module.rs
 create mode 100644 samples/rust/Kconfig
 create mode 100644 samples/rust/Makefile
 create mode 100644 samples/rust/hostprogs/.gitignore
 create mode 100644 samples/rust/hostprogs/Makefile
 create mode 100644 samples/rust/hostprogs/a.rs
 create mode 100644 samples/rust/hostprogs/b.rs
 create mode 100644 samples/rust/hostprogs/single.rs
 create mode 100644 samples/rust/rust_chrdev.rs
 create mode 100644 samples/rust/rust_minimal.rs
 create mode 100644 samples/rust/rust_miscdev.rs
 create mode 100644 samples/rust/rust_module_parameters.rs
 create mode 100644 samples/rust/rust_netfilter.rs
 create mode 100644 samples/rust/rust_platform.rs
 create mode 100644 samples/rust/rust_print.rs
 create mode 100644 samples/rust/rust_random.rs
 create mode 100644 samples/rust/rust_semaphore.rs
 create mode 100644 samples/rust/rust_semaphore_c.c
 create mode 100644 samples/rust/rust_stack_probing.rs
 create mode 100644 samples/rust/rust_sync.rs
 create mode 100755 scripts/generate_rust_analyzer.py
 create mode 100644 scripts/generate_rust_target.rs
 create mode 100755 scripts/is_rust_module.sh
 create mode 100644 scripts/rust-is-available-bindgen-libclang.h
 create mode 100755 scripts/rust-is-available.sh
 create mode 100755 scripts/rustdoc_test_builder.py
 create mode 100755 scripts/rustdoc_test_gen.py


base-commit: 4b0986a3613c92f4ec1bdc7f60ec66fea135991f
-- 
2.36.1


^ permalink raw reply	[flat|nested] 50+ messages in thread

* [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23 19:45   ` Jarkko Sakkinen
  2022-05-23  2:01 ` [PATCH v7 02/25] kallsyms: support "big" kernel symbols Miguel Ojeda
                   ` (20 subsequent siblings)
  21 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Boqun Feng, Kees Cook

From: Boqun Feng <boqun.feng@gmail.com>

This makes it easier to update the size later on.

Furthermore, a static assert is added to ensure both are updated
when that happens. The relationship used is one that keeps the new
size (512+1) close to the original buffer size (500).

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
This is a prerequisite patch, independently submitted at:

    https://lore.kernel.org/lkml/20220506203443.24721-2-ojeda@kernel.org/

 scripts/kallsyms.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 8caabddf817c..82d6508bdf29 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -27,8 +27,18 @@
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
 
+#define _stringify_1(x)	#x
+#define _stringify(x)	_stringify_1(x)
+
 #define KSYM_NAME_LEN		128
 
+/* A substantially bigger size than the current maximum. */
+#define KSYM_NAME_LEN_BUFFER	512
+_Static_assert(
+	KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
+	"Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
+);
+
 struct sym_entry {
 	unsigned long long addr;
 	unsigned int len;
@@ -197,15 +207,15 @@ static void check_symbol_range(const char *sym, unsigned long long addr,
 
 static struct sym_entry *read_symbol(FILE *in)
 {
-	char name[500], type;
+	char name[KSYM_NAME_LEN_BUFFER+1], type;
 	unsigned long long addr;
 	unsigned int len;
 	struct sym_entry *sym;
 	int rc;
 
-	rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
+	rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name);
 	if (rc != 3) {
-		if (rc != EOF && fgets(name, 500, in) == NULL)
+		if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
 			fprintf(stderr, "Read error or end of file.\n");
 		return NULL;
 	}
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 02/25] kallsyms: support "big" kernel symbols
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23 20:30   ` Jarkko Sakkinen
  2022-05-23  2:01 ` [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
                   ` (19 subsequent siblings)
  21 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Kees Cook, Alex Gaynor, Wedson Almeida Filho, Gary Guo,
	Boqun Feng, Matthew Wilcox

Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc.

Increasing to 255 is not enough in some cases, and therefore
we need to introduce longer lengths to the symbol table.

In order to avoid increasing all lengths to 2 bytes (since most
of them are small, including many Rust ones), we use ULEB128 to
keep smaller symbols in 1 byte, with the rest in 2 bytes.

Reviewed-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
This is a prerequisite patch, independently submitted at:

    https://lore.kernel.org/lkml/20220506203443.24721-3-ojeda@kernel.org/

 kernel/kallsyms.c  | 26 ++++++++++++++++++++++----
 scripts/kallsyms.c | 29 ++++++++++++++++++++++++++---
 2 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 79f2eb617a62..e8d2262ef2d2 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -69,12 +69,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off,
 	data = &kallsyms_names[off];
 	len = *data;
 	data++;
+	off++;
+
+	/* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
+	if ((len & 0x80) != 0) {
+		len = (len & 0x7F) | (*data << 7);
+		data++;
+		off++;
+	}
 
 	/*
 	 * Update the offset to return the offset for the next symbol on
 	 * the compressed stream.
 	 */
-	off += len + 1;
+	off += len;
 
 	/*
 	 * For every byte on the compressed symbol data, copy the table
@@ -127,7 +135,7 @@ static char kallsyms_get_symbol_type(unsigned int off)
 static unsigned int get_symbol_offset(unsigned long pos)
 {
 	const u8 *name;
-	int i;
+	int i, len;
 
 	/*
 	 * Use the closest marker we have. We have markers every 256 positions,
@@ -141,8 +149,18 @@ static unsigned int get_symbol_offset(unsigned long pos)
 	 * so we just need to add the len to the current pointer for every
 	 * symbol we wish to skip.
 	 */
-	for (i = 0; i < (pos & 0xFF); i++)
-		name = name + (*name) + 1;
+	for (i = 0; i < (pos & 0xFF); i++) {
+		len = *name;
+
+		/*
+		 * If MSB is 1, it is a "big" symbol, so we need to look into
+		 * the next byte (and skip it, too).
+		 */
+		if ((len & 0x80) != 0)
+			len = ((len & 0x7F) | (name[1] << 7)) + 1;
+
+		name = name + len + 1;
+	}
 
 	return name - kallsyms_names;
 }
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 82d6508bdf29..7e99799aa7b9 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -480,12 +480,35 @@ static void write_src(void)
 		if ((i & 0xFF) == 0)
 			markers[i >> 8] = off;
 
-		printf("\t.byte 0x%02x", table[i]->len);
+		/* There cannot be any symbol of length zero. */
+		if (table[i]->len == 0) {
+			fprintf(stderr, "kallsyms failure: "
+				"unexpected zero symbol length\n");
+			exit(EXIT_FAILURE);
+		}
+
+		/* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
+		if (table[i]->len > 0x3FFF) {
+			fprintf(stderr, "kallsyms failure: "
+				"unexpected huge symbol length\n");
+			exit(EXIT_FAILURE);
+		}
+
+		/* Encode length with ULEB128. */
+		if (table[i]->len <= 0x7F) {
+			/* Most symbols use a single byte for the length. */
+			printf("\t.byte 0x%02x", table[i]->len);
+			off += table[i]->len + 1;
+		} else {
+			/* "Big" symbols use two bytes. */
+			printf("\t.byte 0x%02x, 0x%02x",
+				(table[i]->len & 0x7F) | 0x80,
+				(table[i]->len >> 7) & 0x7F);
+			off += table[i]->len + 2;
+		}
 		for (k = 0; k < table[i]->len; k++)
 			printf(", 0x%02x", table[i]->sym[k]);
 		printf("\n");
-
-		off += table[i]->len + 1;
 	}
 	printf("\n");
 
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 02/25] kallsyms: support "big" kernel symbols Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23 20:31   ` Jarkko Sakkinen
  2022-05-23  2:01 ` [PATCH v7 04/25] kunit: take `kunit_assert` as `const` Miguel Ojeda
                   ` (18 subsequent siblings)
  21 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Kees Cook, Petr Mladek, Alex Gaynor, Wedson Almeida Filho,
	Gary Guo, Boqun Feng, Josh Poimboeuf, Jiri Kosina,
	Miroslav Benes, Joe Lawrence, Peter Zijlstra, Ingo Molnar,
	Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
	Jiri Olsa, Namhyung Kim, live-patching, linux-perf-users

Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc. For instance,
the following code:

    pub mod my_module {
        pub struct MyType;
        pub struct MyGenericType<T>(T);

        pub trait MyTrait {
            fn my_method() -> u32;
        }

        impl MyTrait for MyGenericType<MyType> {
            fn my_method() -> u32 {
                42
            }
        }
    }

generates a symbol of length 96 when using the upcoming v0 mangling scheme:

    _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method

At the moment, Rust symbols may reach up to 300 in length.
Setting 512 as the maximum seems like a reasonable choice to
keep some headroom.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
This is a prerequisite patch, independently submitted at:

    https://lore.kernel.org/lkml/20220506203443.24721-4-ojeda@kernel.org/

 include/linux/kallsyms.h            | 2 +-
 kernel/livepatch/core.c             | 4 ++--
 scripts/kallsyms.c                  | 4 ++--
 tools/include/linux/kallsyms.h      | 2 +-
 tools/lib/perf/include/perf/event.h | 2 +-
 tools/lib/symbol/kallsyms.h         | 2 +-
 6 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index ce1bd2fbf23e..e5ad6e31697d 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -15,7 +15,7 @@
 
 #include <asm/sections.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \
 			(KSYM_NAME_LEN - 1) + \
 			2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index bc475e62279d..ec06ce59d728 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
 	 * we use the smallest/strictest upper bound possible (56, based on
 	 * the current definition of MODULE_NAME_LEN) to prevent overflows.
 	 */
-	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
+	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
 
 	relas = (Elf_Rela *) relasec->sh_addr;
 	/* For each rela in this klp relocation section */
@@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
 
 		/* Format: .klp.sym.sym_objname.sym_name,sympos */
 		cnt = sscanf(strtab + sym->st_name,
-			     ".klp.sym.%55[^.].%127[^,],%lu",
+			     ".klp.sym.%55[^.].%511[^,],%lu",
 			     sym_objname, sym_name, &sympos);
 		if (cnt != 3) {
 			pr_err("symbol %s has an incorrectly formatted name\n",
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 7e99799aa7b9..275044b840dc 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -30,10 +30,10 @@
 #define _stringify_1(x)	#x
 #define _stringify(x)	_stringify_1(x)
 
-#define KSYM_NAME_LEN		128
+#define KSYM_NAME_LEN		512
 
 /* A substantially bigger size than the current maximum. */
-#define KSYM_NAME_LEN_BUFFER	512
+#define KSYM_NAME_LEN_BUFFER	2048
 _Static_assert(
 	KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
 	"Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index efb6c3f5f2a9..5a37ccbec54f 100644
--- a/tools/include/linux/kallsyms.h
+++ b/tools/include/linux/kallsyms.h
@@ -6,7 +6,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
 
 struct module;
 
diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index e7758707cadd..116a80c31675 100644
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -95,7 +95,7 @@ struct perf_record_throttle {
 };
 
 #ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
 #endif
 
 struct perf_record_ksymbol {
diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h
index 72ab9870454b..542f9b059c3b 100644
--- a/tools/lib/symbol/kallsyms.h
+++ b/tools/lib/symbol/kallsyms.h
@@ -7,7 +7,7 @@
 #include <linux/types.h>
 
 #ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
 #endif
 
 static inline u8 kallsyms2elf_binding(char type)
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 04/25] kunit: take `kunit_assert` as `const`
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (2 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23 17:15   ` Daniel Latypov
  2022-05-23  2:01 ` [PATCH v7 05/25] rust: add C helpers Miguel Ojeda
                   ` (17 subsequent siblings)
  21 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Daniel Latypov, Brendan Higgins, linux-kselftest, kunit-dev

The `kunit_do_failed_assertion` function passes its
`struct kunit_assert` argument to `kunit_fail`. This one,
in turn, calls its `format` field passing the assert again
as a `const` pointer.

Therefore, the whole chain may be made `const`.

Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
This is a prerequisite patch, independently submitted at:

    https://lore.kernel.org/lkml/20220502093625.GA23225@kernel.org/

 include/kunit/test.h | 2 +-
 lib/kunit/test.c     | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 00b9ff7783ab..2eff4f1beb42 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -774,7 +774,7 @@ void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...);
 void kunit_do_failed_assertion(struct kunit *test,
 			       const struct kunit_loc *loc,
 			       enum kunit_assert_type type,
-			       struct kunit_assert *assert,
+			       const struct kunit_assert *assert,
 			       const char *fmt, ...);
 
 #define KUNIT_ASSERTION(test, assert_type, pass, assert_class, INITIALIZER, fmt, ...) do { \
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 3bca3bf5c15b..b84aed09a009 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -241,7 +241,7 @@ static void kunit_print_string_stream(struct kunit *test,
 }
 
 static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
-		       enum kunit_assert_type type, struct kunit_assert *assert,
+		       enum kunit_assert_type type, const struct kunit_assert *assert,
 		       const struct va_format *message)
 {
 	struct string_stream *stream;
@@ -281,7 +281,7 @@ static void __noreturn kunit_abort(struct kunit *test)
 void kunit_do_failed_assertion(struct kunit *test,
 			       const struct kunit_loc *loc,
 			       enum kunit_assert_type type,
-			       struct kunit_assert *assert,
+			       const struct kunit_assert *assert,
 			       const char *fmt, ...)
 {
 	va_list args;
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 05/25] rust: add C helpers
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (3 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 04/25] kunit: take `kunit_assert` as `const` Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 06/25] rust: add `compiler_builtins` crate Miguel Ojeda
                   ` (16 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Geoffrey Thomas, Wedson Almeida Filho,
	Sven Van Asbroeck, Gary Guo, Boqun Feng, Maciej Falkowski,
	Wei Liu

This source file contains forwarders to C macros and inlined
functions.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Geoffrey Thomas <geofft@ldpreload.com>
Signed-off-by: Geoffrey Thomas <geofft@ldpreload.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Maciej Falkowski <m.falkowski@samsung.com>
Signed-off-by: Maciej Falkowski <m.falkowski@samsung.com>
Co-developed-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/helpers.c | 644 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 644 insertions(+)
 create mode 100644 rust/helpers.c

diff --git a/rust/helpers.c b/rust/helpers.c
new file mode 100644
index 000000000000..eb7a66c77cb2
--- /dev/null
+++ b/rust/helpers.c
@@ -0,0 +1,644 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
+ * cannot be called either. This file explicitly creates functions ("helpers")
+ * that wrap those so that they can be called from Rust.
+ *
+ * Even though Rust kernel modules should never use directly the bindings, some
+ * of these helpers need to be exported because Rust generics and inlined
+ * functions may not get their code generated in the crate where they are
+ * defined. Other helpers, called from non-inline functions, may not be
+ * exported, in principle. However, in general, the Rust compiler does not
+ * guarantee codegen will be performed for a non-inline function either.
+ * Therefore, this file exports all the helpers. In the future, this may be
+ * revisited to reduce the number of exports after the compiler is informed
+ * about the places codegen is required.
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/bug.h>
+#include <linux/build_bug.h>
+#include <linux/clk.h>
+#include <linux/errname.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sched/signal.h>
+#include <linux/security.h>
+#include <linux/skbuff.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+
+__noreturn void rust_helper_BUG(void)
+{
+	BUG();
+}
+EXPORT_SYMBOL_GPL(rust_helper_BUG);
+
+void rust_helper_clk_disable_unprepare(struct clk *clk)
+{
+	return clk_disable_unprepare(clk);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clk_disable_unprepare);
+
+int rust_helper_clk_prepare_enable(struct clk *clk)
+{
+	return clk_prepare_enable(clk);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clk_prepare_enable);
+
+unsigned long rust_helper_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	return copy_from_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_user);
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+	return copy_to_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_user);
+
+unsigned long rust_helper_clear_user(void __user *to, unsigned long n)
+{
+	return clear_user(to, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clear_user);
+
+void __iomem *rust_helper_ioremap(resource_size_t offset, unsigned long size)
+{
+	return ioremap(offset, size);
+}
+EXPORT_SYMBOL_GPL(rust_helper_ioremap);
+
+u8 rust_helper_readb(const volatile void __iomem *addr)
+{
+	return readb(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readb);
+
+u16 rust_helper_readw(const volatile void __iomem *addr)
+{
+	return readw(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readw);
+
+u32 rust_helper_readl(const volatile void __iomem *addr)
+{
+	return readl(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readl);
+
+#ifdef CONFIG_64BIT
+u64 rust_helper_readq(const volatile void __iomem *addr)
+{
+	return readq(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readq);
+#endif
+
+void rust_helper_writeb(u8 value, volatile void __iomem *addr)
+{
+	writeb(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeb);
+
+void rust_helper_writew(u16 value, volatile void __iomem *addr)
+{
+	writew(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writew);
+
+void rust_helper_writel(u32 value, volatile void __iomem *addr)
+{
+	writel(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writel);
+
+#ifdef CONFIG_64BIT
+void rust_helper_writeq(u64 value, volatile void __iomem *addr)
+{
+	writeq(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeq);
+#endif
+
+u8 rust_helper_readb_relaxed(const volatile void __iomem *addr)
+{
+	return readb_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readb_relaxed);
+
+u16 rust_helper_readw_relaxed(const volatile void __iomem *addr)
+{
+	return readw_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readw_relaxed);
+
+u32 rust_helper_readl_relaxed(const volatile void __iomem *addr)
+{
+	return readl_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readl_relaxed);
+
+#ifdef CONFIG_64BIT
+u64 rust_helper_readq_relaxed(const volatile void __iomem *addr)
+{
+	return readq_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readq_relaxed);
+#endif
+
+void rust_helper_writeb_relaxed(u8 value, volatile void __iomem *addr)
+{
+	writeb_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeb_relaxed);
+
+void rust_helper_writew_relaxed(u16 value, volatile void __iomem *addr)
+{
+	writew_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writew_relaxed);
+
+void rust_helper_writel_relaxed(u32 value, volatile void __iomem *addr)
+{
+	writel_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writel_relaxed);
+
+#ifdef CONFIG_64BIT
+void rust_helper_writeq_relaxed(u64 value, volatile void __iomem *addr)
+{
+	writeq_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeq_relaxed);
+#endif
+
+void rust_helper_memcpy_fromio(void *to, const volatile void __iomem *from, long count)
+{
+	memcpy_fromio(to, from, count);
+}
+EXPORT_SYMBOL_GPL(rust_helper_memcpy_fromio);
+
+void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
+				  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	__spin_lock_init(lock, name, key);
+#else
+	spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
+
+unsigned long rust_helper_spin_lock_irqsave(spinlock_t *lock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	return flags;
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock_irqsave);
+
+void rust_helper_spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
+{
+	spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock_irqrestore);
+
+void rust_helper__raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+				     struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	_raw_spin_lock_init(lock, name, key);
+#else
+	raw_spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper__raw_spin_lock_init);
+
+void rust_helper_raw_spin_lock(raw_spinlock_t *lock)
+{
+	raw_spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_lock);
+
+void rust_helper_raw_spin_unlock(raw_spinlock_t *lock)
+{
+	raw_spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_unlock);
+
+unsigned long rust_helper_raw_spin_lock_irqsave(raw_spinlock_t *lock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(lock, flags);
+
+	return flags;
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_lock_irqsave);
+
+void rust_helper_raw_spin_unlock_irqrestore(raw_spinlock_t *lock,
+					    unsigned long flags)
+{
+	raw_spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_unlock_irqrestore);
+
+void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
+{
+	init_wait(wq_entry);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_wait);
+
+void rust_helper_init_waitqueue_func_entry(struct wait_queue_entry *wq_entry,
+					   wait_queue_func_t func)
+{
+	init_waitqueue_func_entry(wq_entry, func);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_waitqueue_func_entry);
+
+int rust_helper_signal_pending(struct task_struct *t)
+{
+	return signal_pending(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
+
+struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+	return alloc_pages(gfp_mask, order);
+}
+EXPORT_SYMBOL_GPL(rust_helper_alloc_pages);
+
+void *rust_helper_kmap(struct page *page)
+{
+	return kmap(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kmap);
+
+void rust_helper_kunmap(struct page *page)
+{
+	return kunmap(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kunmap);
+
+int rust_helper_cond_resched(void)
+{
+	return cond_resched();
+}
+EXPORT_SYMBOL_GPL(rust_helper_cond_resched);
+
+size_t rust_helper_copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
+{
+	return copy_from_iter(addr, bytes, i);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_iter);
+
+size_t rust_helper_copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
+{
+	return copy_to_iter(addr, bytes, i);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_iter);
+
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+	return IS_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+	return PTR_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
+
+const char *rust_helper_errname(int err)
+{
+	return errname(err);
+}
+EXPORT_SYMBOL_GPL(rust_helper_errname);
+
+void rust_helper_mutex_lock(struct mutex *lock)
+{
+	mutex_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
+
+void rust_helper_amba_set_drvdata(struct amba_device *dev, void *data)
+{
+	amba_set_drvdata(dev, data);
+}
+EXPORT_SYMBOL_GPL(rust_helper_amba_set_drvdata);
+
+void *rust_helper_amba_get_drvdata(struct amba_device *dev)
+{
+	return amba_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_amba_get_drvdata);
+
+void *
+rust_helper_platform_get_drvdata(const struct platform_device *pdev)
+{
+	return platform_get_drvdata(pdev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_platform_get_drvdata);
+
+void
+rust_helper_platform_set_drvdata(struct platform_device *pdev,
+				 void *data)
+{
+	return platform_set_drvdata(pdev, data);
+}
+EXPORT_SYMBOL_GPL(rust_helper_platform_set_drvdata);
+
+refcount_t rust_helper_REFCOUNT_INIT(int n)
+{
+	return (refcount_t)REFCOUNT_INIT(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
+
+void rust_helper_refcount_inc(refcount_t *r)
+{
+	refcount_inc(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
+
+bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+	return refcount_dec_and_test(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
+
+void rust_helper_rb_link_node(struct rb_node *node, struct rb_node *parent,
+			      struct rb_node **rb_link)
+{
+	rb_link_node(node, parent, rb_link);
+}
+EXPORT_SYMBOL_GPL(rust_helper_rb_link_node);
+
+struct task_struct *rust_helper_get_current(void)
+{
+	return current;
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_current);
+
+void rust_helper_get_task_struct(struct task_struct *t)
+{
+	get_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
+
+void rust_helper_put_task_struct(struct task_struct *t)
+{
+	put_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
+
+int rust_helper_security_binder_set_context_mgr(const struct cred *mgr)
+{
+	return security_binder_set_context_mgr(mgr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_set_context_mgr);
+
+int rust_helper_security_binder_transaction(const struct cred *from,
+					    const struct cred *to)
+{
+	return security_binder_transaction(from, to);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transaction);
+
+int rust_helper_security_binder_transfer_binder(const struct cred *from,
+						const struct cred *to)
+{
+	return security_binder_transfer_binder(from, to);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transfer_binder);
+
+int rust_helper_security_binder_transfer_file(const struct cred *from,
+					      const struct cred *to,
+					      struct file *file)
+{
+	return security_binder_transfer_file(from, to, file);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transfer_file);
+
+struct file *rust_helper_get_file(struct file *f)
+{
+	return get_file(f);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_file);
+
+void rust_helper_rcu_read_lock(void)
+{
+	rcu_read_lock();
+}
+EXPORT_SYMBOL_GPL(rust_helper_rcu_read_lock);
+
+void rust_helper_rcu_read_unlock(void)
+{
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(rust_helper_rcu_read_unlock);
+
+void rust_helper_synchronize_rcu(void)
+{
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(rust_helper_synchronize_rcu);
+
+void *rust_helper_dev_get_drvdata(struct device *dev)
+{
+	return dev_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_get_drvdata);
+
+const char *rust_helper_dev_name(const struct device *dev)
+{
+	return dev_name(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_name);
+
+void rust_helper___seqcount_init(seqcount_t *s, const char *name,
+				 struct lock_class_key *key)
+{
+	__seqcount_init(s, name, key);
+}
+EXPORT_SYMBOL_GPL(rust_helper___seqcount_init);
+
+unsigned rust_helper_read_seqcount_begin(seqcount_t *s)
+{
+	return read_seqcount_begin(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_read_seqcount_begin);
+
+int rust_helper_read_seqcount_retry(seqcount_t *s, unsigned start)
+{
+	return read_seqcount_retry(s, start);
+}
+EXPORT_SYMBOL_GPL(rust_helper_read_seqcount_retry);
+
+void rust_helper_write_seqcount_begin(seqcount_t *s)
+{
+	do_write_seqcount_begin(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_write_seqcount_begin);
+
+void rust_helper_write_seqcount_end(seqcount_t *s)
+{
+	do_write_seqcount_end(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_write_seqcount_end);
+
+void rust_helper_irq_set_handler_locked(struct irq_data *data,
+					irq_flow_handler_t handler)
+{
+	irq_set_handler_locked(data, handler);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_set_handler_locked);
+
+void *rust_helper_irq_data_get_irq_chip_data(struct irq_data *d)
+{
+	return irq_data_get_irq_chip_data(d);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_data_get_irq_chip_data);
+
+struct irq_chip *rust_helper_irq_desc_get_chip(struct irq_desc *desc)
+{
+	return irq_desc_get_chip(desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_desc_get_chip);
+
+void *rust_helper_irq_desc_get_handler_data(struct irq_desc *desc)
+{
+	return irq_desc_get_handler_data(desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_desc_get_handler_data);
+
+void rust_helper_chained_irq_enter(struct irq_chip *chip,
+				   struct irq_desc *desc)
+{
+	chained_irq_enter(chip, desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_chained_irq_enter);
+
+void rust_helper_chained_irq_exit(struct irq_chip *chip,
+				   struct irq_desc *desc)
+{
+	chained_irq_exit(chip, desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_chained_irq_exit);
+
+const struct cred *rust_helper_get_cred(const struct cred *cred)
+{
+	return get_cred(cred);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_cred);
+
+void rust_helper_put_cred(const struct cred *cred)
+{
+	put_cred(cred);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_cred);
+
+const struct of_device_id *rust_helper_of_match_device(
+		const struct of_device_id *matches, const struct device *dev)
+{
+	return of_match_device(matches, dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_of_match_device);
+
+void rust_helper_init_completion(struct completion *c)
+{
+	init_completion(c);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_completion);
+
+struct sk_buff *rust_helper_skb_get(struct sk_buff *skb)
+{
+	return skb_get(skb);
+}
+EXPORT_SYMBOL_GPL(rust_helper_skb_get);
+
+unsigned int rust_helper_skb_headlen(const struct sk_buff *skb)
+{
+	return skb_headlen(skb);
+}
+EXPORT_SYMBOL_GPL(rust_helper_skb_headlen);
+
+void rust_helper_dev_hold(struct net_device *dev)
+{
+	return dev_hold(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_hold);
+
+void rust_helper_dev_put(struct net_device *dev)
+{
+	return dev_put(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_put);
+
+struct net *rust_helper_get_net(struct net *net)
+{
+	return get_net(net);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_net);
+
+void rust_helper_put_net(struct net *net)
+{
+	return put_net(net);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_net);
+
+unsigned int rust_helper_NF_QUEUE_NR(unsigned int n)
+{
+	return NF_QUEUE_NR(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_NF_QUEUE_NR);
+
+/*
+ * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
+ * as the Rust `usize` type, so we can use it in contexts where Rust
+ * expects a `usize` like slice (array) indices. `usize` is defined to be
+ * the same as C's `uintptr_t` type (can hold any pointer) but not
+ * necessarily the same as `size_t` (can hold the size of any single
+ * object). Most modern platforms use the same concrete integer type for
+ * both of them, but in case we find ourselves on a platform where
+ * that's not true, fail early instead of risking ABI or
+ * integer-overflow issues.
+ *
+ * If your platform fails this assertion, it means that you are in
+ * danger of integer-overflow bugs (even if you attempt to remove
+ * `--size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
+ * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
+ */
+static_assert(
+	sizeof(size_t) == sizeof(uintptr_t) &&
+	__alignof__(size_t) == __alignof__(uintptr_t),
+	"Rust code expects C `size_t` to match Rust `usize`"
+);
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 06/25] rust: add `compiler_builtins` crate
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (4 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 05/25] rust: add C helpers Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23 18:37   ` Nick Desaulniers
  2022-05-23  2:01 ` [PATCH v7 08/25] rust: adapt `alloc` crate to the kernel Miguel Ojeda
                   ` (15 subsequent siblings)
  21 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Wedson Almeida Filho, Sven Van Asbroeck, Gary Guo

Rust provides `compiler_builtins` as a port of LLVM's `compiler-rt`.
Since we do not need the vast majority of them, we avoid the
dependency by providing our own crate.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/compiler_builtins.rs | 57 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 rust/compiler_builtins.rs

diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
new file mode 100644
index 000000000000..80ca4c0dcd24
--- /dev/null
+++ b/rust/compiler_builtins.rs
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Our own `compiler_builtins`.
+//!
+//! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`].
+//! Since we do not need the vast majority of them, we avoid the dependency
+//! by providing this file.
+//!
+//! At the moment, some builtins are required that should not be. For instance,
+//! [`core`] has 128-bit integers functionality which we should not be compiling
+//! in. We will work with upstream [`core`] to provide feature flags to disable
+//! the parts we do not need. For the moment, we define them to [`panic!`] at
+//! runtime for simplicity to catch mistakes, instead of performing surgery
+//! on `core.o`.
+//!
+//! In any case, all these symbols are weakened to ensure we do not override
+//! those that may be provided by the rest of the kernel.
+//!
+//! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins
+//! [`compiler-rt`]: https://compiler-rt.llvm.org/
+
+#![feature(compiler_builtins)]
+#![compiler_builtins]
+#![no_builtins]
+#![no_std]
+
+macro_rules! define_panicking_intrinsics(
+    ($reason: tt, { $($ident: ident, )* }) => {
+        $(
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern "C" fn $ident() {
+                panic!($reason);
+            }
+        )*
+    }
+);
+
+define_panicking_intrinsics!("`i128` should not be used", {
+    __ashrti3,
+    __muloti4,
+    __multi3,
+});
+
+define_panicking_intrinsics!("`u128` should not be used", {
+    __ashlti3,
+    __lshrti3,
+    __udivmodti4,
+    __udivti3,
+    __umodti3,
+});
+
+#[cfg(target_arch = "arm")]
+define_panicking_intrinsics!("`u64` division/modulo should not be used", {
+    __aeabi_uldivmod,
+    __mulodi4,
+});
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 08/25] rust: adapt `alloc` crate to the kernel
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (5 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 06/25] rust: add `compiler_builtins` crate Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 09/25] rust: add `build_error` crate Miguel Ojeda
                   ` (14 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Wedson Almeida Filho, Gary Guo, Matthew Bakhtiari

This customizes the subset of the Rust standard library `alloc` that
was just imported as-is, mainly by:

  - Adding SPDX license identifiers.

  - Skipping `rc` and `sync` modules via new `cfg`s.

  - Skipping the `vec!` macro.

  - Addding fallible (`try_*`) versions of existing infallible methods
    (i.e. returning a `Result` instead of panicking).

    Since the standard library requires stable/unstable attributes,
    these additions are annotated with:

        #[stable(feature = "kernel", since = "1.0.0")]

    Using "kernel" as the feature allows to have the additions
    clearly marked. The "1.0.0" version is just a placeholder.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/alloc/README.md              |  33 ++++
 rust/alloc/alloc.rs               |   2 +
 rust/alloc/borrow.rs              |   2 +
 rust/alloc/boxed.rs               |   2 +
 rust/alloc/collections/mod.rs     |   2 +
 rust/alloc/fmt.rs                 |   2 +
 rust/alloc/lib.rs                 |   5 +-
 rust/alloc/macros.rs              |   4 +-
 rust/alloc/raw_vec.rs             |  50 ++++-
 rust/alloc/slice.rs               |  93 ++++++++-
 rust/alloc/str.rs                 |  19 ++
 rust/alloc/string.rs              |   6 +-
 rust/alloc/vec/drain.rs           |   2 +
 rust/alloc/vec/drain_filter.rs    |   2 +
 rust/alloc/vec/into_iter.rs       |   2 +
 rust/alloc/vec/is_zero.rs         |   2 +
 rust/alloc/vec/mod.rs             | 313 +++++++++++++++++++++++++++++-
 rust/alloc/vec/partial_eq.rs      |   2 +
 rust/alloc/vec/set_len_on_drop.rs |   2 +
 rust/alloc/vec/spec_extend.rs     |  87 +++++++++
 20 files changed, 623 insertions(+), 9 deletions(-)
 create mode 100644 rust/alloc/README.md

diff --git a/rust/alloc/README.md b/rust/alloc/README.md
new file mode 100644
index 000000000000..9cf0d074c82a
--- /dev/null
+++ b/rust/alloc/README.md
@@ -0,0 +1,33 @@
+# `alloc`
+
+These source files come from the Rust standard library, hosted in
+the https://github.com/rust-lang/rust repository, licensed under
+"Apache-2.0 OR MIT" and adapted for kernel use. For copyright details,
+see https://github.com/rust-lang/rust/blob/master/COPYRIGHT.
+
+Please note that these files should be kept as close as possible to
+upstream. In general, only additions should be performed (e.g. new
+methods). Eventually, changes should make it into upstream so that,
+at some point, this fork can be dropped from the kernel tree.
+
+
+## Rationale
+
+On one hand, kernel folks wanted to keep `alloc` in-tree to have more
+freedom in both workflow and actual features if actually needed
+(e.g. receiver types if we ended up using them), which is reasonable.
+
+On the other hand, Rust folks wanted to keep `alloc` as close as
+upstream as possible and avoid as much divergence as possible, which
+is also reasonable.
+
+We agreed on a middle-ground: we would keep a subset of `alloc`
+in-tree that would be as small and as close as possible to upstream.
+Then, upstream can start adding the functions that we add to `alloc`
+etc., until we reach a point where the kernel already knows exactly
+what it needs in `alloc` and all the new methods are merged into
+upstream, so that we can drop `alloc` from the kernel tree and go back
+to using the upstream one.
+
+By doing this, the kernel can go a bit faster now, and Rust can
+slowly incorporate and discuss the changes as needed.
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index 9d4f9af91a5e..cea3b747673f 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Memory allocation APIs
 
 #![stable(feature = "alloc_module", since = "1.28.0")]
diff --git a/rust/alloc/borrow.rs b/rust/alloc/borrow.rs
index 63234ee91f09..8e1d8a764641 100644
--- a/rust/alloc/borrow.rs
+++ b/rust/alloc/borrow.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A module for working with borrowed data.
 
 #![stable(feature = "rust1", since = "1.0.0")]
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
index f753189c6830..921fcef75e4b 100644
--- a/rust/alloc/boxed.rs
+++ b/rust/alloc/boxed.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A pointer type for heap allocation.
 //!
 //! [`Box<T>`], casually referred to as a 'box', provides the simplest form of
diff --git a/rust/alloc/collections/mod.rs b/rust/alloc/collections/mod.rs
index 628a5b155673..1eec265b28f8 100644
--- a/rust/alloc/collections/mod.rs
+++ b/rust/alloc/collections/mod.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Collection types.
 
 #![stable(feature = "rust1", since = "1.0.0")]
diff --git a/rust/alloc/fmt.rs b/rust/alloc/fmt.rs
index aeb7554f8e91..be75e6637442 100644
--- a/rust/alloc/fmt.rs
+++ b/rust/alloc/fmt.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Utilities for formatting and printing `String`s.
 //!
 //! This module contains the runtime support for the [`format!`] syntax extension.
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
index 6da32df57efb..085dc005170a 100644
--- a/rust/alloc/lib.rs
+++ b/rust/alloc/lib.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! # The Rust core allocation and collections library
 //!
 //! This library provides smart pointers and collections for managing
@@ -204,11 +206,12 @@ mod boxed {
 pub mod borrow;
 pub mod collections;
 pub mod fmt;
+#[cfg(not(no_rc))]
 pub mod rc;
 pub mod slice;
 pub mod str;
 pub mod string;
-#[cfg(target_has_atomic = "ptr")]
+#[cfg(all(not(no_sync), target_has_atomic = "ptr"))]
 pub mod sync;
 #[cfg(all(not(no_global_oom_handling), target_has_atomic = "ptr"))]
 pub mod task;
diff --git a/rust/alloc/macros.rs b/rust/alloc/macros.rs
index d3e9e65c3fe5..47ebcd5277d1 100644
--- a/rust/alloc/macros.rs
+++ b/rust/alloc/macros.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 /// Creates a [`Vec`] containing the arguments.
 ///
 /// `vec!` allows `Vec`s to be defined with the same syntax as array expressions.
@@ -34,7 +36,7 @@
 /// be mindful of side effects.
 ///
 /// [`Vec`]: crate::vec::Vec
-#[cfg(not(test))]
+#[cfg(all(not(no_global_oom_handling), not(test)))]
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "vec_macro"]
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
index 8fa0242ca9a9..018c4657f580 100644
--- a/rust/alloc/raw_vec.rs
+++ b/rust/alloc/raw_vec.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #![unstable(feature = "raw_vec_internals", reason = "unstable const warnings", issue = "none")]
 
 use core::alloc::LayoutError;
@@ -18,10 +20,10 @@ use crate::collections::TryReserveErrorKind::*;
 #[cfg(test)]
 mod tests;
 
-#[cfg(not(no_global_oom_handling))]
 enum AllocInit {
     /// The contents of the new memory are uninitialized.
     Uninitialized,
+    #[allow(dead_code)]
     /// The new memory is guaranteed to be zeroed.
     Zeroed,
 }
@@ -132,6 +134,13 @@ impl<T, A: Allocator> RawVec<T, A> {
         Self::allocate_in(capacity, AllocInit::Uninitialized, alloc)
     }
 
+    /// Like `try_with_capacity`, but parameterized over the choice of
+    /// allocator for the returned `RawVec`.
+    #[inline]
+    pub fn try_with_capacity_in(capacity: usize, alloc: A) -> Result<Self, TryReserveError> {
+        Self::try_allocate_in(capacity, AllocInit::Uninitialized, alloc)
+    }
+
     /// Like `with_capacity_zeroed`, but parameterized over the choice
     /// of allocator for the returned `RawVec`.
     #[cfg(not(no_global_oom_handling))]
@@ -201,6 +210,29 @@ impl<T, A: Allocator> RawVec<T, A> {
         }
     }
 
+    fn try_allocate_in(capacity: usize, init: AllocInit, alloc: A) -> Result<Self, TryReserveError> {
+        if mem::size_of::<T>() == 0 {
+            return Ok(Self::new_in(alloc));
+        }
+
+        let layout = Layout::array::<T>(capacity).map_err(|_| CapacityOverflow)?;
+        alloc_guard(layout.size())?;
+        let result = match init {
+            AllocInit::Uninitialized => alloc.allocate(layout),
+            AllocInit::Zeroed => alloc.allocate_zeroed(layout),
+        };
+        let ptr = result.map_err(|_| AllocError { layout, non_exhaustive: () })?;
+
+        // Allocators currently return a `NonNull<[u8]>` whose length
+        // matches the size requested. If that ever changes, the capacity
+        // here should change to `ptr.len() / mem::size_of::<T>()`.
+        Ok(Self {
+            ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
+            cap: capacity,
+            alloc,
+        })
+    }
+
     /// Reconstitutes a `RawVec` from a pointer, capacity, and allocator.
     ///
     /// # Safety
@@ -309,6 +341,12 @@ impl<T, A: Allocator> RawVec<T, A> {
         }
     }
 
+    /// The same as `reserve_for_push`, but returns on errors instead of panicking or aborting.
+    #[inline(never)]
+    pub fn try_reserve_for_push(&mut self, len: usize) -> Result<(), TryReserveError> {
+        self.grow_amortized(len, 1)
+    }
+
     /// Ensures that the buffer contains at least enough space to hold `len +
     /// additional` elements. If it doesn't already, will reallocate the
     /// minimum possible amount of memory necessary. Generally this will be
@@ -354,6 +392,16 @@ impl<T, A: Allocator> RawVec<T, A> {
     pub fn shrink_to_fit(&mut self, cap: usize) {
         handle_reserve(self.shrink(cap));
     }
+
+    /// Tries to shrink the buffer down to the specified capacity. If the given amount
+    /// is 0, actually completely deallocates.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the given amount is *larger* than the current capacity.
+    pub fn try_shrink_to_fit(&mut self, cap: usize) -> Result<(), TryReserveError> {
+        self.shrink(cap)
+    }
 }
 
 impl<T, A: Allocator> RawVec<T, A> {
diff --git a/rust/alloc/slice.rs b/rust/alloc/slice.rs
index f0397d08f95a..8cb5170f639d 100644
--- a/rust/alloc/slice.rs
+++ b/rust/alloc/slice.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A dynamically-sized view into a contiguous sequence, `[T]`.
 //!
 //! *[See also the slice primitive type](slice).*
@@ -93,11 +95,11 @@ use core::mem::size_of;
 use core::ptr;
 
 use crate::alloc::Allocator;
-#[cfg(not(no_global_oom_handling))]
 use crate::alloc::Global;
 #[cfg(not(no_global_oom_handling))]
 use crate::borrow::ToOwned;
 use crate::boxed::Box;
+use crate::collections::TryReserveError;
 use crate::vec::Vec;
 
 #[unstable(feature = "slice_range", issue = "76393")]
@@ -157,6 +159,7 @@ mod hack {
     use core::alloc::Allocator;
 
     use crate::boxed::Box;
+    use crate::collections::TryReserveError;
     use crate::vec::Vec;
 
     // We shouldn't add inline attribute to this since this is used in
@@ -176,6 +179,11 @@ mod hack {
         T::to_vec(s, alloc)
     }
 
+    #[inline]
+    pub fn try_to_vec<T: TryConvertVec, A: Allocator>(s: &[T], alloc: A) -> Result<Vec<T, A>, TryReserveError> {
+        T::try_to_vec(s, alloc)
+    }
+
     #[cfg(not(no_global_oom_handling))]
     pub trait ConvertVec {
         fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A>
@@ -183,6 +191,12 @@ mod hack {
             Self: Sized;
     }
 
+    pub trait TryConvertVec {
+        fn try_to_vec<A: Allocator>(s: &[Self], alloc: A) -> Result<Vec<Self, A>, TryReserveError>
+        where
+            Self: Sized;
+    }
+
     #[cfg(not(no_global_oom_handling))]
     impl<T: Clone> ConvertVec for T {
         #[inline]
@@ -235,6 +249,42 @@ mod hack {
             v
         }
     }
+
+    impl<T: Clone> TryConvertVec for T {
+        #[inline]
+        default fn try_to_vec<A: Allocator>(s: &[Self], alloc: A) -> Result<Vec<Self, A>, TryReserveError> {
+            struct DropGuard<'a, T, A: Allocator> {
+                vec: &'a mut Vec<T, A>,
+                num_init: usize,
+            }
+            impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> {
+                #[inline]
+                fn drop(&mut self) {
+                    // SAFETY:
+                    // items were marked initialized in the loop below
+                    unsafe {
+                        self.vec.set_len(self.num_init);
+                    }
+                }
+            }
+            let mut vec = Vec::try_with_capacity_in(s.len(), alloc)?;
+            let mut guard = DropGuard { vec: &mut vec, num_init: 0 };
+            let slots = guard.vec.spare_capacity_mut();
+            // .take(slots.len()) is necessary for LLVM to remove bounds checks
+            // and has better codegen than zip.
+            for (i, b) in s.iter().enumerate().take(slots.len()) {
+                guard.num_init = i;
+                slots[i].write(b.clone());
+            }
+            core::mem::forget(guard);
+            // SAFETY:
+            // the vec was allocated and initialized above to at least this length.
+            unsafe {
+                vec.set_len(s.len());
+            }
+            Ok(vec)
+        }
+    }
 }
 
 #[lang = "slice_alloc"]
@@ -477,6 +527,24 @@ impl<T> [T] {
         self.to_vec_in(Global)
     }
 
+    /// Tries to copy `self` into a new `Vec`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s = [10, 40, 30];
+    /// let x = s.try_to_vec().unwrap();
+    /// // Here, `s` and `x` can be modified independently.
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_to_vec(&self) -> Result<Vec<T>, TryReserveError>
+    where
+        T: Clone,
+    {
+        self.try_to_vec_in(Global)
+    }
+
     /// Copies `self` into a new `Vec` with an allocator.
     ///
     /// # Examples
@@ -501,6 +569,29 @@ impl<T> [T] {
         hack::to_vec(self, alloc)
     }
 
+    /// Tries to copy `self` into a new `Vec` with an allocator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let s = [10, 40, 30];
+    /// let x = s.try_to_vec_in(System).unwrap();
+    /// // Here, `s` and `x` can be modified independently.
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_to_vec_in<A: Allocator>(&self, alloc: A) -> Result<Vec<T, A>, TryReserveError>
+    where
+        T: Clone,
+    {
+        // N.B., see the `hack` module in this file for more details.
+        hack::try_to_vec(self, alloc)
+    }
+
     /// Converts `self` into a vector without clones or allocation.
     ///
     /// The resulting vector can be converted back into a box via
diff --git a/rust/alloc/str.rs b/rust/alloc/str.rs
index 69495f31c32c..a1370c2d674c 100644
--- a/rust/alloc/str.rs
+++ b/rust/alloc/str.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Unicode string slices.
 //!
 //! *[See also the `str` primitive type](str).*
@@ -36,6 +38,7 @@ use core::unicode::conversions;
 
 use crate::borrow::ToOwned;
 use crate::boxed::Box;
+use crate::collections::TryReserveError;
 use crate::slice::{Concat, Join, SliceIndex};
 use crate::string::String;
 use crate::vec::Vec;
@@ -590,6 +593,22 @@ impl str {
         // make_ascii_lowercase() preserves the UTF-8 invariant.
         unsafe { String::from_utf8_unchecked(bytes) }
     }
+
+    /// Tries to create a `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s: &str = "a";
+    /// let ss: String = s.try_to_owned().unwrap();
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_to_owned(&self) -> Result<String, TryReserveError> {
+        unsafe { Ok(String::from_utf8_unchecked(self.as_bytes().try_to_vec()?)) }
+    }
 }
 
 /// Converts a boxed slice of bytes to a boxed string slice without checking
diff --git a/rust/alloc/string.rs b/rust/alloc/string.rs
index 716bb4983a65..5b9780cfc11f 100644
--- a/rust/alloc/string.rs
+++ b/rust/alloc/string.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A UTF-8–encoded, growable string.
 //!
 //! This module contains the [`String`] type, the [`ToString`] trait for
@@ -47,8 +49,8 @@ use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
 use core::fmt;
 use core::hash;
 #[cfg(not(no_global_oom_handling))]
-use core::iter::FromIterator;
-use core::iter::{from_fn, FusedIterator};
+use core::iter::{from_fn, FromIterator};
+use core::iter::FusedIterator;
 #[cfg(not(no_global_oom_handling))]
 use core::ops::Add;
 #[cfg(not(no_global_oom_handling))]
diff --git a/rust/alloc/vec/drain.rs b/rust/alloc/vec/drain.rs
index 1bff19d05c10..8116ba6dfd9e 100644
--- a/rust/alloc/vec/drain.rs
+++ b/rust/alloc/vec/drain.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::alloc::{Allocator, Global};
 use core::fmt;
 use core::iter::{FusedIterator, TrustedLen};
diff --git a/rust/alloc/vec/drain_filter.rs b/rust/alloc/vec/drain_filter.rs
index 3c37c92ae44b..b04fce041622 100644
--- a/rust/alloc/vec/drain_filter.rs
+++ b/rust/alloc/vec/drain_filter.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::alloc::{Allocator, Global};
 use core::ptr::{self};
 use core::slice::{self};
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
index f985fb78465b..11d01ac868ca 100644
--- a/rust/alloc/vec/into_iter.rs
+++ b/rust/alloc/vec/into_iter.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::alloc::{Allocator, Global};
 use crate::raw_vec::RawVec;
 use core::fmt;
diff --git a/rust/alloc/vec/is_zero.rs b/rust/alloc/vec/is_zero.rs
index 0efc4893c3c4..40e1e667c9fb 100644
--- a/rust/alloc/vec/is_zero.rs
+++ b/rust/alloc/vec/is_zero.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::boxed::Box;
 
 #[rustc_specialization_trait]
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
index c29aa0fec5b8..a2b1dfca3561 100644
--- a/rust/alloc/vec/mod.rs
+++ b/rust/alloc/vec/mod.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A contiguous growable array type with heap-allocated contents, written
 //! `Vec<T>`.
 //!
@@ -118,10 +120,8 @@ use self::spec_from_elem::SpecFromElem;
 #[cfg(not(no_global_oom_handling))]
 mod spec_from_elem;
 
-#[cfg(not(no_global_oom_handling))]
 use self::set_len_on_drop::SetLenOnDrop;
 
-#[cfg(not(no_global_oom_handling))]
 mod set_len_on_drop;
 
 #[cfg(not(no_global_oom_handling))]
@@ -145,7 +145,8 @@ mod spec_from_iter;
 #[cfg(not(no_global_oom_handling))]
 use self::spec_extend::SpecExtend;
 
-#[cfg(not(no_global_oom_handling))]
+use self::spec_extend::TrySpecExtend;
+
 mod spec_extend;
 
 /// A contiguous growable array type, written as `Vec<T>`, short for 'vector'.
@@ -470,6 +471,49 @@ impl<T> Vec<T> {
         Self::with_capacity_in(capacity, Global)
     }
 
+    /// Tries to construct a new, empty `Vec<T>` with the specified capacity.
+    ///
+    /// The vector will be able to hold exactly `capacity` elements without
+    /// reallocating. If `capacity` is 0, the vector will not allocate.
+    ///
+    /// It is important to note that although the returned vector has the
+    /// *capacity* specified, the vector will have a zero *length*. For an
+    /// explanation of the difference between length and capacity, see
+    /// *[Capacity and reallocation]*.
+    ///
+    /// [Capacity and reallocation]: #capacity-and-reallocation
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::try_with_capacity(10).unwrap();
+    ///
+    /// // The vector contains no items, even though it has capacity for more
+    /// assert_eq!(vec.len(), 0);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // These are all done without reallocating...
+    /// for i in 0..10 {
+    ///     vec.push(i);
+    /// }
+    /// assert_eq!(vec.len(), 10);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// vec.push(11);
+    /// assert_eq!(vec.len(), 11);
+    /// assert!(vec.capacity() >= 11);
+    ///
+    /// let mut result = Vec::try_with_capacity(usize::MAX);
+    /// assert!(result.is_err());
+    /// ```
+    #[inline]
+    #[doc(alias = "malloc")]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_with_capacity(capacity: usize) -> Result<Self, TryReserveError> {
+        Self::try_with_capacity_in(capacity, Global)
+    }
+
     /// Creates a `Vec<T>` directly from the raw components of another vector.
     ///
     /// # Safety
@@ -609,6 +653,53 @@ impl<T, A: Allocator> Vec<T, A> {
         Vec { buf: RawVec::with_capacity_in(capacity, alloc), len: 0 }
     }
 
+    /// Tries to construct a new, empty `Vec<T, A>` with the specified capacity
+    /// with the provided allocator.
+    ///
+    /// The vector will be able to hold exactly `capacity` elements without
+    /// reallocating. If `capacity` is 0, the vector will not allocate.
+    ///
+    /// It is important to note that although the returned vector has the
+    /// *capacity* specified, the vector will have a zero *length*. For an
+    /// explanation of the difference between length and capacity, see
+    /// *[Capacity and reallocation]*.
+    ///
+    /// [Capacity and reallocation]: #capacity-and-reallocation
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut vec = Vec::try_with_capacity_in(10, System).unwrap();
+    ///
+    /// // The vector contains no items, even though it has capacity for more
+    /// assert_eq!(vec.len(), 0);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // These are all done without reallocating...
+    /// for i in 0..10 {
+    ///     vec.push(i);
+    /// }
+    /// assert_eq!(vec.len(), 10);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// vec.push(11);
+    /// assert_eq!(vec.len(), 11);
+    /// assert!(vec.capacity() >= 11);
+    ///
+    /// let mut result = Vec::try_with_capacity_in(usize::MAX, System);
+    /// assert!(result.is_err());
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_with_capacity_in(capacity: usize, alloc: A) -> Result<Self, TryReserveError> {
+        Ok(Vec { buf: RawVec::try_with_capacity_in(capacity, alloc)?, len: 0 })
+    }
+
     /// Creates a `Vec<T, A>` directly from the raw components of another vector.
     ///
     /// # Safety
@@ -940,6 +1031,33 @@ impl<T, A: Allocator> Vec<T, A> {
         }
     }
 
+    /// Tries to shrink the capacity of the vector as much as possible.
+    ///
+    /// It will drop down as close as possible to the length but the allocator
+    /// may still inform the vector that there is space for a few more elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    /// assert_eq!(vec.capacity(), 10);
+    /// vec.try_shrink_to_fit().unwrap();
+    /// assert!(vec.capacity() >= 3);
+    /// ```
+    #[doc(alias = "realloc")]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_shrink_to_fit(&mut self) -> Result<(), TryReserveError> {
+        // The capacity is never less than the length, and there's nothing to do when
+        // they are equal, so we can avoid the panic case in `RawVec::try_shrink_to_fit`
+        // by only calling it with a greater capacity.
+        if self.capacity() <= self.len {
+            return Ok(());
+        }
+
+        self.buf.try_shrink_to_fit(self.len)
+    }
+
     /// Shrinks the capacity of the vector with a lower bound.
     ///
     /// The capacity will remain at least as large as both the length
@@ -1002,6 +1120,41 @@ impl<T, A: Allocator> Vec<T, A> {
         }
     }
 
+    /// Tries to convert the vector into [`Box<[T]>`][owned slice].
+    ///
+    /// Note that this will drop any excess capacity.
+    ///
+    /// [owned slice]: Box
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = vec![1, 2, 3];
+    ///
+    /// let slice = v.try_into_boxed_slice().unwrap();
+    /// ```
+    ///
+    /// Any excess capacity is removed:
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    ///
+    /// assert_eq!(vec.capacity(), 10);
+    /// let slice = vec.try_into_boxed_slice().unwrap();
+    /// assert_eq!(slice.into_vec().capacity(), 3);
+    /// ```
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_into_boxed_slice(mut self) -> Result<Box<[T], A>, TryReserveError> {
+        unsafe {
+            self.try_shrink_to_fit()?;
+            let me = ManuallyDrop::new(self);
+            let buf = ptr::read(&me.buf);
+            let len = me.len();
+            Ok(buf.into_box(len).assume_init())
+        }
+    }
+
     /// Shortens the vector, keeping the first `len` elements and dropping
     /// the rest.
     ///
@@ -1735,6 +1888,29 @@ impl<T, A: Allocator> Vec<T, A> {
         }
     }
 
+    /// Tries to append an element to the back of a collection.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2];
+    /// vec.try_push(3).unwrap();
+    /// assert_eq!(vec, [1, 2, 3]);
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_push(&mut self, value: T) -> Result<(), TryReserveError> {
+        if self.len == self.buf.capacity() {
+            self.buf.try_reserve_for_push(self.len)?;
+        }
+        unsafe {
+            let end = self.as_mut_ptr().add(self.len);
+            ptr::write(end, value);
+            self.len += 1;
+        }
+        Ok(())
+    }
+
     /// Removes the last element from a vector and returns it, or [`None`] if it
     /// is empty.
     ///
@@ -1799,6 +1975,17 @@ impl<T, A: Allocator> Vec<T, A> {
         self.len += count;
     }
 
+    /// Tries to append elements to `Self` from other buffer.
+    #[inline]
+    unsafe fn try_append_elements(&mut self, other: *const [T]) -> Result<(), TryReserveError> {
+        let count = unsafe { (*other).len() };
+        self.try_reserve(count)?;
+        let len = self.len();
+        unsafe { ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count) };
+        self.len += count;
+        Ok(())
+    }
+
     /// Removes the specified range from the vector in bulk, returning all
     /// removed elements as an iterator. If the iterator is dropped before
     /// being fully consumed, it drops the remaining removed elements.
@@ -2209,6 +2396,44 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
         }
     }
 
+    /// Tries to resize the `Vec` in-place so that `len` is equal to `new_len`.
+    ///
+    /// If `new_len` is greater than `len`, the `Vec` is extended by the
+    /// difference, with each additional slot filled with `value`.
+    /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+    ///
+    /// This method requires `T` to implement [`Clone`],
+    /// in order to be able to clone the passed value.
+    /// If you need more flexibility (or want to rely on [`Default`] instead of
+    /// [`Clone`]), use [`Vec::resize_with`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec!["hello"];
+    /// vec.try_resize(3, "world").unwrap();
+    /// assert_eq!(vec, ["hello", "world", "world"]);
+    ///
+    /// let mut vec = vec![1, 2, 3, 4];
+    /// vec.try_resize(2, 0).unwrap();
+    /// assert_eq!(vec, [1, 2]);
+    ///
+    /// let mut vec = vec![42];
+    /// let result = vec.try_resize(usize::MAX, 0);
+    /// assert!(result.is_err());
+    /// ```
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_resize(&mut self, new_len: usize, value: T) -> Result<(), TryReserveError> {
+        let len = self.len();
+
+        if new_len > len {
+            self.try_extend_with(new_len - len, ExtendElement(value))
+        } else {
+            self.truncate(new_len);
+            Ok(())
+        }
+    }
+
     /// Clones and appends all elements in a slice to the `Vec`.
     ///
     /// Iterates over the slice `other`, clones each element, and then appends
@@ -2234,6 +2459,30 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
         self.spec_extend(other.iter())
     }
 
+    /// Tries to clone and append all elements in a slice to the `Vec`.
+    ///
+    /// Iterates over the slice `other`, clones each element, and then appends
+    /// it to this `Vec`. The `other` slice is traversed in-order.
+    ///
+    /// Note that this function is same as [`extend`] except that it is
+    /// specialized to work with slices instead. If and when Rust gets
+    /// specialization this function will likely be deprecated (but still
+    /// available).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1];
+    /// vec.try_extend_from_slice(&[2, 3, 4]).unwrap();
+    /// assert_eq!(vec, [1, 2, 3, 4]);
+    /// ```
+    ///
+    /// [`extend`]: Vec::extend
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), TryReserveError> {
+        self.try_spec_extend(other.iter())
+    }
+
     /// Copies elements from `src` range to the end of the vector.
     ///
     /// # Panics
@@ -2328,6 +2577,36 @@ impl<T, A: Allocator> Vec<T, A> {
             // len set by scope guard
         }
     }
+
+    /// Try to extend the vector by `n` values, using the given generator.
+    fn try_extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) -> Result<(), TryReserveError> {
+        self.try_reserve(n)?;
+
+        unsafe {
+            let mut ptr = self.as_mut_ptr().add(self.len());
+            // Use SetLenOnDrop to work around bug where compiler
+            // might not realize the store through `ptr` through self.set_len()
+            // don't alias.
+            let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+            // Write all elements except the last one
+            for _ in 1..n {
+                ptr::write(ptr, value.next());
+                ptr = ptr.offset(1);
+                // Increment the length in every step in case next() panics
+                local_len.increment_len(1);
+            }
+
+            if n > 0 {
+                // We can write the last element directly without cloning needlessly
+                ptr::write(ptr, value.last());
+                local_len.increment_len(1);
+            }
+
+            // len set by scope guard
+            Ok(())
+        }
+    }
 }
 
 impl<T: PartialEq, A: Allocator> Vec<T, A> {
@@ -2662,6 +2941,34 @@ impl<T, A: Allocator> Vec<T, A> {
         }
     }
 
+    // leaf method to which various SpecFrom/SpecExtend implementations delegate when
+    // they have no further optimizations to apply
+    fn try_extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) -> Result<(), TryReserveError> {
+        // This is the case for a general iterator.
+        //
+        // This function should be the moral equivalent of:
+        //
+        //      for item in iterator {
+        //          self.push(item);
+        //      }
+        while let Some(element) = iterator.next() {
+            let len = self.len();
+            if len == self.capacity() {
+                let (lower, _) = iterator.size_hint();
+                self.try_reserve(lower.saturating_add(1))?;
+            }
+            unsafe {
+                ptr::write(self.as_mut_ptr().add(len), element);
+                // Since next() executes user code which can panic we have to bump the length
+                // after each step.
+                // NB can't overflow since we would have had to alloc the address space
+                self.set_len(len + 1);
+            }
+        }
+
+        Ok(())
+    }
+
     /// Creates a splicing iterator that replaces the specified range in the vector
     /// with the given `replace_with` iterator and yields the removed items.
     /// `replace_with` does not need to be the same length as `range`.
diff --git a/rust/alloc/vec/partial_eq.rs b/rust/alloc/vec/partial_eq.rs
index 50e140961050..273e99bed488 100644
--- a/rust/alloc/vec/partial_eq.rs
+++ b/rust/alloc/vec/partial_eq.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::alloc::Allocator;
 #[cfg(not(no_global_oom_handling))]
 use crate::borrow::Cow;
diff --git a/rust/alloc/vec/set_len_on_drop.rs b/rust/alloc/vec/set_len_on_drop.rs
index 8b66bc812129..448bf5076a0b 100644
--- a/rust/alloc/vec/set_len_on_drop.rs
+++ b/rust/alloc/vec/set_len_on_drop.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
 //
 // The idea is: The length field in SetLenOnDrop is a local variable
diff --git a/rust/alloc/vec/spec_extend.rs b/rust/alloc/vec/spec_extend.rs
index c3b4534096de..729f4bb1709f 100644
--- a/rust/alloc/vec/spec_extend.rs
+++ b/rust/alloc/vec/spec_extend.rs
@@ -1,4 +1,7 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::alloc::Allocator;
+use crate::collections::{TryReserveError, TryReserveErrorKind};
 use core::iter::TrustedLen;
 use core::ptr::{self};
 use core::slice::{self};
@@ -6,10 +9,17 @@ use core::slice::{self};
 use super::{IntoIter, SetLenOnDrop, Vec};
 
 // Specialization trait used for Vec::extend
+#[cfg(not(no_global_oom_handling))]
 pub(super) trait SpecExtend<T, I> {
     fn spec_extend(&mut self, iter: I);
 }
 
+// Specialization trait used for Vec::try_extend
+pub(super) trait TrySpecExtend<T, I> {
+    fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError>;
+}
+
+#[cfg(not(no_global_oom_handling))]
 impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
 where
     I: Iterator<Item = T>,
@@ -19,6 +29,16 @@ where
     }
 }
 
+impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
+where
+    I: Iterator<Item = T>,
+{
+    default fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError> {
+        self.try_extend_desugared(iter)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
 impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
 where
     I: TrustedLen<Item = T>,
@@ -57,6 +77,41 @@ where
     }
 }
 
+impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
+where
+    I: TrustedLen<Item = T>,
+{
+    default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
+        // This is the case for a TrustedLen iterator.
+        let (low, high) = iterator.size_hint();
+        if let Some(additional) = high {
+            debug_assert_eq!(
+                low,
+                additional,
+                "TrustedLen iterator's size hint is not exact: {:?}",
+                (low, high)
+            );
+            self.try_reserve(additional)?;
+            unsafe {
+                let mut ptr = self.as_mut_ptr().add(self.len());
+                let mut local_len = SetLenOnDrop::new(&mut self.len);
+                iterator.for_each(move |element| {
+                    ptr::write(ptr, element);
+                    ptr = ptr.offset(1);
+                    // Since the loop executes user code which can panic we have to bump the pointer
+                    // after each step.
+                    // NB can't overflow since we would have had to alloc the address space
+                    local_len.increment_len(1);
+                });
+            }
+            Ok(())
+        } else {
+            Err(TryReserveErrorKind::CapacityOverflow.into())
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
 impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
     fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
         unsafe {
@@ -66,6 +121,17 @@ impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
     }
 }
 
+impl<T, A: Allocator> TrySpecExtend<T, IntoIter<T>> for Vec<T, A> {
+    fn try_spec_extend(&mut self, mut iterator: IntoIter<T>) -> Result<(), TryReserveError> {
+        unsafe {
+            self.try_append_elements(iterator.as_slice() as _)?;
+        }
+        iterator.ptr = iterator.end;
+        Ok(())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
 impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
 where
     I: Iterator<Item = &'a T>,
@@ -76,6 +142,17 @@ where
     }
 }
 
+impl<'a, T: 'a, I, A: Allocator + 'a> TrySpecExtend<&'a T, I> for Vec<T, A>
+where
+    I: Iterator<Item = &'a T>,
+    T: Clone,
+{
+    default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
+        self.try_spec_extend(iterator.cloned())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
 impl<'a, T: 'a, A: Allocator + 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
 where
     T: Copy,
@@ -85,3 +162,13 @@ where
         unsafe { self.append_elements(slice) };
     }
 }
+
+impl<'a, T: 'a, A: Allocator + 'a> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+where
+    T: Copy,
+{
+    fn try_spec_extend(&mut self, iterator: slice::Iter<'a, T>) -> Result<(), TryReserveError> {
+        let slice = iterator.as_slice();
+        unsafe { self.try_append_elements(slice) }
+    }
+}
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 09/25] rust: add `build_error` crate
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (6 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 08/25] rust: adapt `alloc` crate to the kernel Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 10/25] rust: add `macros` crate Miguel Ojeda
                   ` (13 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Gary Guo, Alex Gaynor, Wedson Almeida Filho

From: Gary Guo <gary@garyguo.net>

The `build_error` crate provides the `build_error` function which
is then used to provide the `build_error!` and the `build_assert!`
macros.

`build_assert!` is intended to be used when `static_assert!` cannot
be used, e.g. when the condition refers to generic parameters or
parameters of an inline function.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/build_error.rs | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 rust/build_error.rs

diff --git a/rust/build_error.rs b/rust/build_error.rs
new file mode 100644
index 000000000000..34e589149d3e
--- /dev/null
+++ b/rust/build_error.rs
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Build-time error.
+//!
+//! This crate provides a function `build_error`, which will panic in
+//! compile-time if executed in const context, and will cause a build error
+//! if not executed at compile time and the optimizer does not optimise away the
+//! call.
+//!
+//! It is used by `build_assert!` in the kernel crate, allowing checking of
+//! conditions that could be checked statically, but could not be enforced in
+//! Rust yet (e.g. perform some checks in const functions, but those
+//! functions could still be called in the runtime).
+
+#![no_std]
+
+/// Panics if executed in const context, or triggers a build error if not.
+#[inline(never)]
+#[cold]
+#[no_mangle]
+#[track_caller]
+pub const fn build_error(msg: &'static str) -> ! {
+    panic!("{}", msg);
+}
+
+#[cfg(CONFIG_RUST_BUILD_ASSERT_WARN)]
+#[link_section = ".gnu.warning.build_error"]
+#[used]
+static BUILD_ERROR_WARNING: [u8; 45] = *b"call to build_error present after compilation";
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 10/25] rust: add `macros` crate
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (7 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 09/25] rust: add `build_error` crate Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 13/25] rust: export generated symbols Miguel Ojeda
                   ` (12 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Finn Behrens, Adam Bratschi-Kaye,
	Wedson Almeida Filho, Sumera Priyadarsini, Gary Guo,
	Matthew Bakhtiari

This crate contains all the procedural macros ("proc macros")
shared by all the kernel.

Procedural macros allow to create syntax extensions. They run at
compile-time and can consume as well as produce Rust syntax.

For instance, the `module!` macro that is used by Rust modules
is implemented here. It allows to easily declare the equivalent
information to the `MODULE_*` macros in C modules, e.g.:

    module! {
        type: RustMinimal,
        name: b"rust_minimal",
        author: b"Rust for Linux Contributors",
        description: b"Rust minimal sample",
        license: b"GPL",
    }

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/macros/helpers.rs |  79 ++++++
 rust/macros/lib.rs     |  94 ++++++
 rust/macros/module.rs  | 631 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 804 insertions(+)
 create mode 100644 rust/macros/helpers.rs
 create mode 100644 rust/macros/lib.rs
 create mode 100644 rust/macros/module.rs

diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
new file mode 100644
index 000000000000..ad210563e5a6
--- /dev/null
+++ b/rust/macros/helpers.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Group, TokenTree};
+
+pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
+    if let Some(TokenTree::Ident(ident)) = it.next() {
+        Some(ident.to_string())
+    } else {
+        None
+    }
+}
+
+pub(crate) fn try_literal(it: &mut token_stream::IntoIter) -> Option<String> {
+    if let Some(TokenTree::Literal(literal)) = it.next() {
+        Some(literal.to_string())
+    } else {
+        None
+    }
+}
+
+pub(crate) fn try_byte_string(it: &mut token_stream::IntoIter) -> Option<String> {
+    try_literal(it).and_then(|byte_string| {
+        if byte_string.starts_with("b\"") && byte_string.ends_with('\"') {
+            Some(byte_string[2..byte_string.len() - 1].to_string())
+        } else {
+            None
+        }
+    })
+}
+
+pub(crate) fn expect_ident(it: &mut token_stream::IntoIter) -> String {
+    try_ident(it).expect("Expected Ident")
+}
+
+pub(crate) fn expect_punct(it: &mut token_stream::IntoIter) -> char {
+    if let TokenTree::Punct(punct) = it.next().expect("Reached end of token stream for Punct") {
+        punct.as_char()
+    } else {
+        panic!("Expected Punct");
+    }
+}
+
+pub(crate) fn expect_literal(it: &mut token_stream::IntoIter) -> String {
+    try_literal(it).expect("Expected Literal")
+}
+
+pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group {
+    if let TokenTree::Group(group) = it.next().expect("Reached end of token stream for Group") {
+        group
+    } else {
+        panic!("Expected Group");
+    }
+}
+
+pub(crate) fn expect_byte_string(it: &mut token_stream::IntoIter) -> String {
+    try_byte_string(it).expect("Expected byte string")
+}
+
+pub(crate) fn expect_end(it: &mut token_stream::IntoIter) {
+    if it.next().is_some() {
+        panic!("Expected end");
+    }
+}
+
+pub(crate) fn get_literal(it: &mut token_stream::IntoIter, expected_name: &str) -> String {
+    assert_eq!(expect_ident(it), expected_name);
+    assert_eq!(expect_punct(it), ':');
+    let literal = expect_literal(it);
+    assert_eq!(expect_punct(it), ',');
+    literal
+}
+
+pub(crate) fn get_byte_string(it: &mut token_stream::IntoIter, expected_name: &str) -> String {
+    assert_eq!(expect_ident(it), expected_name);
+    assert_eq!(expect_punct(it), ':');
+    let byte_string = expect_byte_string(it);
+    assert_eq!(expect_punct(it), ',');
+    byte_string
+}
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
new file mode 100644
index 000000000000..d4ac221387a1
--- /dev/null
+++ b/rust/macros/lib.rs
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Crate for all kernel procedural macros.
+
+mod helpers;
+mod module;
+
+use proc_macro::TokenStream;
+
+/// Declares a kernel module.
+///
+/// The `type` argument should be a type which implements the [`Module`]
+/// trait. Also accepts various forms of kernel metadata.
+///
+/// C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+///
+/// [`Module`]: ../kernel/trait.Module.html
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// module!{
+///     type: MyModule,
+///     name: b"my_kernel_module",
+///     author: b"Rust for Linux Contributors",
+///     description: b"My very own kernel module!",
+///     license: b"GPL",
+///     params: {
+///        my_i32: i32 {
+///            default: 42,
+///            permissions: 0o000,
+///            description: b"Example of i32",
+///        },
+///        writeable_i32: i32 {
+///            default: 42,
+///            permissions: 0o644,
+///            description: b"Example of i32",
+///        },
+///    },
+/// }
+///
+/// struct MyModule;
+///
+/// impl kernel::Module for MyModule {
+///     fn init() -> Result<Self> {
+///         // If the parameter is writeable, then the kparam lock must be
+///         // taken to read the parameter:
+///         {
+///             let lock = THIS_MODULE.kernel_param_lock();
+///             pr_info!("i32 param is:  {}\n", writeable_i32.read(&lock));
+///         }
+///         // If the parameter is read only, it can be read without locking
+///         // the kernel parameters:
+///         pr_info!("i32 param is:  {}\n", my_i32.read());
+///         Ok(Self)
+///     }
+/// }
+/// ```
+///
+/// # Supported argument types
+///   - `type`: type which implements the [`Module`] trait (required).
+///   - `name`: byte array of the name of the kernel module (required).
+///   - `author`: byte array of the author of the kernel module.
+///   - `description`: byte array of the description of the kernel module.
+///   - `license`: byte array of the license of the kernel module (required).
+///   - `alias`: byte array of alias name of the kernel module.
+///   - `alias_rtnl_link`: byte array of the `rtnl_link_alias` of the kernel module (mutually exclusive with `alias`).
+///   - `params`: parameters for the kernel module, as described below.
+///
+/// # Supported parameter types
+///
+///   - `bool`: Corresponds to C `bool` param type.
+///   - `i8`: No equivalent C param type.
+///   - `u8`: Corresponds to C `char` param type.
+///   - `i16`: Corresponds to C `short` param type.
+///   - `u16`: Corresponds to C `ushort` param type.
+///   - `i32`: Corresponds to C `int` param type.
+///   - `u32`: Corresponds to C `uint` param type.
+///   - `i64`: No equivalent C param type.
+///   - `u64`: Corresponds to C `ullong` param type.
+///   - `isize`: No equivalent C param type.
+///   - `usize`: No equivalent C param type.
+///   - `str`: Corresponds to C `charp` param type. Reading returns a byte slice.
+///   - `ArrayParam<T,N>`: Corresponds to C parameters created using `module_param_array`. An array
+///     of `T`'s of length at **most** `N`.
+///
+/// `invbool` is unsupported: it was only ever used in a few modules.
+/// Consider using a `bool` and inverting the logic instead.
+#[proc_macro]
+pub fn module(ts: TokenStream) -> TokenStream {
+    module::module(ts)
+}
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
new file mode 100644
index 000000000000..323934b24e7f
--- /dev/null
+++ b/rust/macros/module.rs
@@ -0,0 +1,631 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Delimiter, Group, Literal, TokenStream, TokenTree};
+
+use crate::helpers::*;
+
+#[derive(Clone, PartialEq)]
+enum ParamType {
+    Ident(String),
+    Array { vals: String, max_length: usize },
+}
+
+fn expect_array_fields(it: &mut token_stream::IntoIter) -> ParamType {
+    assert_eq!(expect_punct(it), '<');
+    let vals = expect_ident(it);
+    assert_eq!(expect_punct(it), ',');
+    let max_length_str = expect_literal(it);
+    let max_length = max_length_str
+        .parse::<usize>()
+        .expect("Expected usize length");
+    assert_eq!(expect_punct(it), '>');
+    ParamType::Array { vals, max_length }
+}
+
+fn expect_type(it: &mut token_stream::IntoIter) -> ParamType {
+    if let TokenTree::Ident(ident) = it
+        .next()
+        .expect("Reached end of token stream for param type")
+    {
+        match ident.to_string().as_ref() {
+            "ArrayParam" => expect_array_fields(it),
+            _ => ParamType::Ident(ident.to_string()),
+        }
+    } else {
+        panic!("Expected Param Type")
+    }
+}
+
+struct ModInfoBuilder<'a> {
+    module: &'a str,
+    counter: usize,
+    buffer: String,
+}
+
+impl<'a> ModInfoBuilder<'a> {
+    fn new(module: &'a str) -> Self {
+        ModInfoBuilder {
+            module,
+            counter: 0,
+            buffer: String::new(),
+        }
+    }
+
+    fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
+        use std::fmt::Write;
+
+        let string = if builtin {
+            // Built-in modules prefix their modinfo strings by `module.`.
+            format!(
+                "{module}.{field}={content}\0",
+                module = self.module,
+                field = field,
+                content = content
+            )
+        } else {
+            // Loadable modules' modinfo strings go as-is.
+            format!("{field}={content}\0", field = field, content = content)
+        };
+
+        write!(
+            &mut self.buffer,
+            "
+                {cfg}
+                #[doc(hidden)]
+                #[link_section = \".modinfo\"]
+                #[used]
+                pub static __{module}_{counter}: [u8; {length}] = *{string};
+            ",
+            cfg = if builtin {
+                "#[cfg(not(MODULE))]"
+            } else {
+                "#[cfg(MODULE)]"
+            },
+            module = self.module,
+            counter = self.counter,
+            length = string.len(),
+            string = Literal::byte_string(string.as_bytes()),
+        )
+        .unwrap();
+
+        self.counter += 1;
+    }
+
+    fn emit_only_builtin(&mut self, field: &str, content: &str) {
+        self.emit_base(field, content, true)
+    }
+
+    fn emit_only_loadable(&mut self, field: &str, content: &str) {
+        self.emit_base(field, content, false)
+    }
+
+    fn emit(&mut self, field: &str, content: &str) {
+        self.emit_only_builtin(field, content);
+        self.emit_only_loadable(field, content);
+    }
+
+    fn emit_param(&mut self, field: &str, param: &str, content: &str) {
+        let content = format!("{param}:{content}", param = param, content = content);
+        self.emit(field, &content);
+    }
+}
+
+fn permissions_are_readonly(perms: &str) -> bool {
+    let (radix, digits) = if let Some(n) = perms.strip_prefix("0x") {
+        (16, n)
+    } else if let Some(n) = perms.strip_prefix("0o") {
+        (8, n)
+    } else if let Some(n) = perms.strip_prefix("0b") {
+        (2, n)
+    } else {
+        (10, perms)
+    };
+    match u32::from_str_radix(digits, radix) {
+        Ok(perms) => perms & 0o222 == 0,
+        Err(_) => false,
+    }
+}
+
+fn param_ops_path(param_type: &str) -> &'static str {
+    match param_type {
+        "bool" => "kernel::module_param::PARAM_OPS_BOOL",
+        "i8" => "kernel::module_param::PARAM_OPS_I8",
+        "u8" => "kernel::module_param::PARAM_OPS_U8",
+        "i16" => "kernel::module_param::PARAM_OPS_I16",
+        "u16" => "kernel::module_param::PARAM_OPS_U16",
+        "i32" => "kernel::module_param::PARAM_OPS_I32",
+        "u32" => "kernel::module_param::PARAM_OPS_U32",
+        "i64" => "kernel::module_param::PARAM_OPS_I64",
+        "u64" => "kernel::module_param::PARAM_OPS_U64",
+        "isize" => "kernel::module_param::PARAM_OPS_ISIZE",
+        "usize" => "kernel::module_param::PARAM_OPS_USIZE",
+        "str" => "kernel::module_param::PARAM_OPS_STR",
+        t => panic!("Unrecognized type {}", t),
+    }
+}
+
+fn try_simple_param_val(
+    param_type: &str,
+) -> Box<dyn Fn(&mut token_stream::IntoIter) -> Option<String>> {
+    match param_type {
+        "bool" => Box::new(try_ident),
+        "str" => Box::new(|param_it| {
+            try_byte_string(param_it)
+                .map(|s| format!("kernel::module_param::StringParam::Ref(b\"{}\")", s))
+        }),
+        _ => Box::new(try_literal),
+    }
+}
+
+fn get_default(param_type: &ParamType, param_it: &mut token_stream::IntoIter) -> String {
+    let try_param_val = match param_type {
+        ParamType::Ident(ref param_type)
+        | ParamType::Array {
+            vals: ref param_type,
+            max_length: _,
+        } => try_simple_param_val(param_type),
+    };
+    assert_eq!(expect_ident(param_it), "default");
+    assert_eq!(expect_punct(param_it), ':');
+    let default = match param_type {
+        ParamType::Ident(_) => try_param_val(param_it).expect("Expected default param value"),
+        ParamType::Array {
+            vals: _,
+            max_length: _,
+        } => {
+            let group = expect_group(param_it);
+            assert_eq!(group.delimiter(), Delimiter::Bracket);
+            let mut default_vals = Vec::new();
+            let mut it = group.stream().into_iter();
+
+            while let Some(default_val) = try_param_val(&mut it) {
+                default_vals.push(default_val);
+                match it.next() {
+                    Some(TokenTree::Punct(punct)) => assert_eq!(punct.as_char(), ','),
+                    None => break,
+                    _ => panic!("Expected ',' or end of array default values"),
+                }
+            }
+
+            let mut default_array = "kernel::module_param::ArrayParam::create(&[".to_string();
+            default_array.push_str(
+                &default_vals
+                    .iter()
+                    .map(|val| val.to_string())
+                    .collect::<Vec<String>>()
+                    .join(","),
+            );
+            default_array.push_str("])");
+            default_array
+        }
+    };
+    assert_eq!(expect_punct(param_it), ',');
+    default
+}
+
+fn generated_array_ops_name(vals: &str, max_length: usize) -> String {
+    format!(
+        "__generated_array_ops_{vals}_{max_length}",
+        vals = vals,
+        max_length = max_length
+    )
+}
+
+#[derive(Debug, Default)]
+struct ModuleInfo {
+    type_: String,
+    license: String,
+    name: String,
+    author: Option<String>,
+    description: Option<String>,
+    alias: Option<String>,
+    params: Option<Group>,
+}
+
+impl ModuleInfo {
+    fn parse(it: &mut token_stream::IntoIter) -> Self {
+        let mut info = ModuleInfo::default();
+
+        const EXPECTED_KEYS: &[&str] = &[
+            "type",
+            "name",
+            "author",
+            "description",
+            "license",
+            "alias",
+            "alias_rtnl_link",
+            "params",
+        ];
+        const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
+        let mut seen_keys = Vec::new();
+
+        loop {
+            let key = match it.next() {
+                Some(TokenTree::Ident(ident)) => ident.to_string(),
+                Some(_) => panic!("Expected Ident or end"),
+                None => break,
+            };
+
+            if seen_keys.contains(&key) {
+                panic!(
+                    "Duplicated key \"{}\". Keys can only be specified once.",
+                    key
+                );
+            }
+
+            assert_eq!(expect_punct(it), ':');
+
+            match key.as_str() {
+                "type" => info.type_ = expect_ident(it),
+                "name" => info.name = expect_byte_string(it),
+                "author" => info.author = Some(expect_byte_string(it)),
+                "description" => info.description = Some(expect_byte_string(it)),
+                "license" => info.license = expect_byte_string(it),
+                "alias" => info.alias = Some(expect_byte_string(it)),
+                "alias_rtnl_link" => {
+                    info.alias = Some(format!("rtnl-link-{}", expect_byte_string(it)))
+                }
+                "params" => info.params = Some(expect_group(it)),
+                _ => panic!(
+                    "Unknown key \"{}\". Valid keys are: {:?}.",
+                    key, EXPECTED_KEYS
+                ),
+            }
+
+            assert_eq!(expect_punct(it), ',');
+
+            seen_keys.push(key);
+        }
+
+        expect_end(it);
+
+        for key in REQUIRED_KEYS {
+            if !seen_keys.iter().any(|e| e == key) {
+                panic!("Missing required key \"{}\".", key);
+            }
+        }
+
+        let mut ordered_keys: Vec<&str> = Vec::new();
+        for key in EXPECTED_KEYS {
+            if seen_keys.iter().any(|e| e == key) {
+                ordered_keys.push(key);
+            }
+        }
+
+        if seen_keys != ordered_keys {
+            panic!(
+                "Keys are not ordered as expected. Order them like: {:?}.",
+                ordered_keys
+            );
+        }
+
+        info
+    }
+}
+
+pub(crate) fn module(ts: TokenStream) -> TokenStream {
+    let mut it = ts.into_iter();
+
+    let info = ModuleInfo::parse(&mut it);
+
+    let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
+    if let Some(author) = info.author {
+        modinfo.emit("author", &author);
+    }
+    if let Some(description) = info.description {
+        modinfo.emit("description", &description);
+    }
+    modinfo.emit("license", &info.license);
+    if let Some(alias) = info.alias {
+        modinfo.emit("alias", &alias);
+    }
+
+    // Built-in modules also export the `file` modinfo string.
+    let file =
+        std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
+    modinfo.emit_only_builtin("file", &file);
+
+    let mut array_types_to_generate = Vec::new();
+    if let Some(params) = info.params {
+        assert_eq!(params.delimiter(), Delimiter::Brace);
+
+        let mut it = params.stream().into_iter();
+
+        loop {
+            let param_name = match it.next() {
+                Some(TokenTree::Ident(ident)) => ident.to_string(),
+                Some(_) => panic!("Expected Ident or end"),
+                None => break,
+            };
+
+            assert_eq!(expect_punct(&mut it), ':');
+            let param_type = expect_type(&mut it);
+            let group = expect_group(&mut it);
+            assert_eq!(expect_punct(&mut it), ',');
+
+            assert_eq!(group.delimiter(), Delimiter::Brace);
+
+            let mut param_it = group.stream().into_iter();
+            let param_default = get_default(&param_type, &mut param_it);
+            let param_permissions = get_literal(&mut param_it, "permissions");
+            let param_description = get_byte_string(&mut param_it, "description");
+            expect_end(&mut param_it);
+
+            // TODO: More primitive types.
+            // TODO: Other kinds: unsafes, etc.
+            let (param_kernel_type, ops): (String, _) = match param_type {
+                ParamType::Ident(ref param_type) => (
+                    param_type.to_string(),
+                    param_ops_path(param_type).to_string(),
+                ),
+                ParamType::Array {
+                    ref vals,
+                    max_length,
+                } => {
+                    array_types_to_generate.push((vals.clone(), max_length));
+                    (
+                        format!("__rust_array_param_{}_{}", vals, max_length),
+                        generated_array_ops_name(vals, max_length),
+                    )
+                }
+            };
+
+            modinfo.emit_param("parmtype", &param_name, &param_kernel_type);
+            modinfo.emit_param("parm", &param_name, &param_description);
+            let param_type_internal = match param_type {
+                ParamType::Ident(ref param_type) => match param_type.as_ref() {
+                    "str" => "kernel::module_param::StringParam".to_string(),
+                    other => other.to_string(),
+                },
+                ParamType::Array {
+                    ref vals,
+                    max_length,
+                } => format!(
+                    "kernel::module_param::ArrayParam<{vals}, {max_length}>",
+                    vals = vals,
+                    max_length = max_length
+                ),
+            };
+            let read_func = if permissions_are_readonly(&param_permissions) {
+                format!(
+                    "
+                        fn read(&self) -> &<{param_type_internal} as kernel::module_param::ModuleParam>::Value {{
+                            // SAFETY: Parameters do not need to be locked because they are read only or sysfs is not enabled.
+                            unsafe {{ <{param_type_internal} as kernel::module_param::ModuleParam>::value(&__{name}_{param_name}_value) }}
+                        }}
+                    ",
+                    name = info.name,
+                    param_name = param_name,
+                    param_type_internal = param_type_internal,
+                )
+            } else {
+                format!(
+                    "
+                        fn read<'lck>(&self, lock: &'lck kernel::KParamGuard) -> &'lck <{param_type_internal} as kernel::module_param::ModuleParam>::Value {{
+                            // SAFETY: Parameters are locked by `KParamGuard`.
+                            unsafe {{ <{param_type_internal} as kernel::module_param::ModuleParam>::value(&__{name}_{param_name}_value) }}
+                        }}
+                    ",
+                    name = info.name,
+                    param_name = param_name,
+                    param_type_internal = param_type_internal,
+                )
+            };
+            let kparam = format!(
+                "
+                    kernel::bindings::kernel_param__bindgen_ty_1 {{
+                        arg: unsafe {{ &__{name}_{param_name}_value }} as *const _ as *mut kernel::c_types::c_void,
+                    }},
+                ",
+                name = info.name,
+                param_name = param_name,
+            );
+            modinfo.buffer.push_str(
+                &format!(
+                    "
+                    static mut __{name}_{param_name}_value: {param_type_internal} = {param_default};
+
+                    struct __{name}_{param_name};
+
+                    impl __{name}_{param_name} {{ {read_func} }}
+
+                    const {param_name}: __{name}_{param_name} = __{name}_{param_name};
+
+                    // Note: the C macro that generates the static structs for the `__param` section
+                    // asks for them to be `aligned(sizeof(void *))`. However, that was put in place
+                    // in 2003 in commit 38d5b085d2 (\"[PATCH] Fix over-alignment problem on x86-64\")
+                    // to undo GCC over-alignment of static structs of >32 bytes. It seems that is
+                    // not the case anymore, so we simplify to a transparent representation here
+                    // in the expectation that it is not needed anymore.
+                    // TODO: Revisit this to confirm the above comment and remove it if it happened.
+                    #[repr(transparent)]
+                    struct __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param);
+
+                    unsafe impl Sync for __{name}_{param_name}_RacyKernelParam {{
+                    }}
+
+                    #[cfg(not(MODULE))]
+                    const __{name}_{param_name}_name: *const kernel::c_types::c_char = b\"{name}.{param_name}\\0\" as *const _ as *const kernel::c_types::c_char;
+
+                    #[cfg(MODULE)]
+                    const __{name}_{param_name}_name: *const kernel::c_types::c_char = b\"{param_name}\\0\" as *const _ as *const kernel::c_types::c_char;
+
+                    #[link_section = \"__param\"]
+                    #[used]
+                    static __{name}_{param_name}_struct: __{name}_{param_name}_RacyKernelParam = __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param {{
+                        name: __{name}_{param_name}_name,
+                        // SAFETY: `__this_module` is constructed by the kernel at load time and will not be freed until the module is unloaded.
+                        #[cfg(MODULE)]
+                        mod_: unsafe {{ &kernel::bindings::__this_module as *const _ as *mut _ }},
+                        #[cfg(not(MODULE))]
+                        mod_: core::ptr::null_mut(),
+                        ops: unsafe {{ &{ops} }} as *const kernel::bindings::kernel_param_ops,
+                        perm: {permissions},
+                        level: -1,
+                        flags: 0,
+                        __bindgen_anon_1: {kparam}
+                    }});
+                    ",
+                    name = info.name,
+                    param_type_internal = param_type_internal,
+                    read_func = read_func,
+                    param_default = param_default,
+                    param_name = param_name,
+                    ops = ops,
+                    permissions = param_permissions,
+                    kparam = kparam,
+                )
+            );
+        }
+    }
+
+    let mut generated_array_types = String::new();
+
+    for (vals, max_length) in array_types_to_generate {
+        let ops_name = generated_array_ops_name(&vals, max_length);
+        generated_array_types.push_str(&format!(
+            "
+                kernel::make_param_ops!(
+                    {ops_name},
+                    kernel::module_param::ArrayParam<{vals}, {{ {max_length} }}>
+                );
+            ",
+            ops_name = ops_name,
+            vals = vals,
+            max_length = max_length,
+        ));
+    }
+
+    format!(
+        "
+            /// The module name.
+            ///
+            /// Used by the printing macros, e.g. [`info!`].
+            const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
+
+            /// The \"Rust loadable module\" mark, for `scripts/is_rust_module.sh`.
+            //
+            // This may be best done another way later on, e.g. as a new modinfo
+            // key or a new section. For the moment, keep it simple.
+            #[cfg(MODULE)]
+            #[doc(hidden)]
+            #[used]
+            static __IS_RUST_MODULE: () = ();
+
+            static mut __MOD: Option<{type_}> = None;
+
+            // SAFETY: `__this_module` is constructed by the kernel at load time and will not be freed until the module is unloaded.
+            #[cfg(MODULE)]
+            static THIS_MODULE: kernel::ThisModule = unsafe {{ kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _) }};
+            #[cfg(not(MODULE))]
+            static THIS_MODULE: kernel::ThisModule = unsafe {{ kernel::ThisModule::from_ptr(core::ptr::null_mut()) }};
+
+            // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
+            #[cfg(MODULE)]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn init_module() -> kernel::c_types::c_int {{
+                __init()
+            }}
+
+            #[cfg(MODULE)]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn cleanup_module() {{
+                __exit()
+            }}
+
+            // Built-in modules are initialized through an initcall pointer
+            // and the identifiers need to be unique.
+            #[cfg(not(MODULE))]
+            #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
+            #[doc(hidden)]
+            #[link_section = \"{initcall_section}\"]
+            #[used]
+            pub static __{name}_initcall: extern \"C\" fn() -> kernel::c_types::c_int = __{name}_init;
+
+            #[cfg(not(MODULE))]
+            #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
+            core::arch::global_asm!(
+                r#\".section \"{initcall_section}\", \"a\"
+                __{name}_initcall:
+                    .long   __{name}_init - .
+                    .previous
+                \"#
+            );
+
+            #[cfg(not(MODULE))]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn __{name}_init() -> kernel::c_types::c_int {{
+                __init()
+            }}
+
+            #[cfg(not(MODULE))]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn __{name}_exit() {{
+                __exit()
+            }}
+
+            fn __init() -> kernel::c_types::c_int {{
+                match <{type_} as kernel::Module>::init(kernel::c_str!(\"{name}\"), &THIS_MODULE) {{
+                    Ok(m) => {{
+                        unsafe {{
+                            __MOD = Some(m);
+                        }}
+                        return 0;
+                    }}
+                    Err(e) => {{
+                        return e.to_kernel_errno();
+                    }}
+                }}
+            }}
+
+            fn __exit() {{
+                unsafe {{
+                    // Invokes `drop()` on `__MOD`, which should be used for cleanup.
+                    __MOD = None;
+                }}
+            }}
+
+            {modinfo}
+
+            {generated_array_types}
+        ",
+        type_ = info.type_,
+        name = info.name,
+        modinfo = modinfo.buffer,
+        generated_array_types = generated_array_types,
+        initcall_section = ".initcall6.init"
+    ).parse().expect("Error parsing formatted string into token stream.")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_permissions_are_readonly() {
+        assert!(permissions_are_readonly("0b000000000"));
+        assert!(permissions_are_readonly("0o000"));
+        assert!(permissions_are_readonly("000"));
+        assert!(permissions_are_readonly("0x000"));
+
+        assert!(!permissions_are_readonly("0b111111111"));
+        assert!(!permissions_are_readonly("0o777"));
+        assert!(!permissions_are_readonly("511"));
+        assert!(!permissions_are_readonly("0x1ff"));
+
+        assert!(permissions_are_readonly("0o014"));
+        assert!(permissions_are_readonly("0o015"));
+
+        assert!(!permissions_are_readonly("0o214"));
+        assert!(!permissions_are_readonly("0o024"));
+        assert!(!permissions_are_readonly("0o012"));
+
+        assert!(!permissions_are_readonly("0o315"));
+        assert!(!permissions_are_readonly("0o065"));
+        assert!(!permissions_are_readonly("0o017"));
+    }
+}
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 13/25] rust: export generated symbols
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (8 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 10/25] rust: add `macros` crate Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 14/25] vsprintf: add new `%pA` format specifier Miguel Ojeda
                   ` (11 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Wedson Almeida Filho

All symbols are reexported reusing the `EXPORT_SYMBOL_GPL` macro
from C. The lists of symbols are generated on the fly.

There are three main sets of symbols to distinguish:

  - The ones from the `core` and `alloc` crates (from the Rust
    standard library). The code is licensed as Apache/MIT.

  - The ones from our abstractions in the `kernel` crate.

  - The helpers (already exported since they are not generated).

We export everything as GPL. This ensures we do not mistakenly
expose GPL kernel symbols/features as non-GPL, even indirectly.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/exports.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 rust/exports.c

diff --git a/rust/exports.c b/rust/exports.c
new file mode 100644
index 000000000000..fe3dcfdd6fbf
--- /dev/null
+++ b/rust/exports.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A hack to export Rust symbols for loadable modules without having to redo
+ * the entire `include/linux/export.h` logic in Rust.
+ *
+ * This requires the Rust's new/future `v0` mangling scheme because the default
+ * one ("legacy") uses invalid characters for C identifiers (thus we cannot use
+ * the `EXPORT_SYMBOL_*` macros).
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ */
+
+#include <linux/module.h>
+
+#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym);
+
+#include "exports_core_generated.h"
+#include "exports_alloc_generated.h"
+#include "exports_kernel_generated.h"
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 14/25] vsprintf: add new `%pA` format specifier
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (9 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 13/25] rust: export generated symbols Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side Miguel Ojeda
                   ` (10 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Gary Guo, Kees Cook, Petr Mladek, Alex Gaynor,
	Wedson Almeida Filho, Steven Rostedt, Sergey Senozhatsky,
	Andy Shevchenko, Rasmus Villemoes, Jonathan Corbet, linux-doc

From: Gary Guo <gary@garyguo.net>

This patch adds a format specifier `%pA` to `vsprintf` which formats
a pointer as `core::fmt::Arguments`. Doing so allows us to directly
format to the internal buffer of `printf`, so we do not have to use
a temporary buffer on the stack to pre-assemble the message on
the Rust side.

This specifier is intended only to be used from Rust and not for C, so
`checkpatch.pl` is intentionally unchanged to catch any misuse.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 Documentation/core-api/printk-formats.rst | 10 ++++++++++
 lib/vsprintf.c                            | 13 +++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 5e89497ba314..dbe1aacc79d0 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -625,6 +625,16 @@ Examples::
 	%p4cc	Y10  little-endian (0x20303159)
 	%p4cc	NV12 big-endian (0xb231564e)
 
+Rust
+----
+
+::
+
+	%pA
+
+Only intended to be used from Rust code to format ``core::fmt::Arguments``.
+Do *not* use it from C.
+
 Thanks
 ======
 
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 40d26a07a133..00f71f91d991 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2270,6 +2270,9 @@ int __init no_hash_pointers_enable(char *str)
 }
 early_param("no_hash_pointers", no_hash_pointers_enable);
 
+/* Used for Rust formatting ('%pA'). */
+char *rust_fmt_argument(char *buf, char *end, void *ptr);
+
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
  * by an extra set of alphanumeric characters that are extended format
@@ -2396,6 +2399,10 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
  *
  * Note: The default behaviour (unadorned %p) is to hash the address,
  * rendering it useful as a unique identifier.
+ *
+ * There is also a '%pA' format specifier, but it is only intended to be used
+ * from Rust code to format core::fmt::Arguments. Do *not* use it from C.
+ * See rust/kernel/print.rs for details.
  */
 static noinline_for_stack
 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
@@ -2468,6 +2475,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 		return device_node_string(buf, end, ptr, spec, fmt + 1);
 	case 'f':
 		return fwnode_string(buf, end, ptr, spec, fmt + 1);
+	case 'A':
+		if (!IS_ENABLED(CONFIG_RUST)) {
+			WARN_ONCE(1, "Please remove %%pA from non-Rust code\n");
+			return error_string(buf, end, "(%pA?)", spec);
+		}
+		return rust_fmt_argument(buf, end, ptr);
 	case 'x':
 		return pointer_string(buf, end, ptr, spec);
 	case 'e':
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (10 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 14/25] vsprintf: add new `%pA` format specifier Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:17   ` Joe Perches
  2022-05-23  2:01 ` [PATCH v7 16/25] scripts: checkpatch: enable language-independent checks for Rust Miguel Ojeda
                   ` (9 subsequent siblings)
  21 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Kees Cook, Alex Gaynor, Wedson Almeida Filho, Andy Whitcroft,
	Joe Perches, Dwaipayan Ray, Lukas Bulwahn

The `%pA` format specifier is only intended to be used from Rust.

`checkpatch.pl` already gives a warning for invalid specificers:

    WARNING: Invalid vsprintf pointer extension '%pA'

With this change, we introduce an error message with further
explanation:

    ERROR: '%pA' is only intended to be used from Rust code

Suggested-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 scripts/checkpatch.pl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 577e02998701..457d544b0b9d 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6784,6 +6784,10 @@ sub process {
 					my $stat_real = get_stat_real($linenr, $lc);
 					my $ext_type = "Invalid";
 					my $use = "";
+					if ($bad_specifier =~ /pA/) {
+						ERROR("VSPRINTF_RUST",
+							"'\%pA' is only intended to be used from Rust code\n" . "$here\n$stat_real\n");
+					}
 					if ($bad_specifier =~ /p[Ff]/) {
 						$use = " - use %pS instead";
 						$use =~ s/pS/ps/ if ($bad_specifier =~ /pf/);
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 16/25] scripts: checkpatch: enable language-independent checks for Rust
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (11 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 17/25] scripts: add `rustdoc_test_{builder,gen}.py` scripts Miguel Ojeda
                   ` (8 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Wedson Almeida Filho, Andy Whitcroft, Joe Perches,
	Dwaipayan Ray, Lukas Bulwahn

Include Rust in the "source code files" category, so that
the language-independent tests are checked for Rust too,
and teach `checkpatch` about the comment style for Rust files.

This enables the malformed SPDX check, the misplaced SPDX license
tag check, the long line checks, the lines without a newline check
and the embedded filename check.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 scripts/checkpatch.pl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 457d544b0b9d..923e82467fe5 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3615,7 +3615,7 @@ sub process {
 				my $comment = "";
 				if ($realfile =~ /\.(h|s|S)$/) {
 					$comment = '/*';
-				} elsif ($realfile =~ /\.(c|dts|dtsi)$/) {
+				} elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) {
 					$comment = '//';
 				} elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) {
 					$comment = '#';
@@ -3663,7 +3663,7 @@ sub process {
 		}
 
 # check we are in a valid source file if not then ignore this hunk
-		next if ($realfile !~ /\.(h|c|s|S|sh|dtsi|dts)$/);
+		next if ($realfile !~ /\.(h|c|rs|s|S|sh|dtsi|dts)$/);
 
 # check for using SPDX-License-Identifier on the wrong line number
 		if ($realline != $checklicenseline &&
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 17/25] scripts: add `rustdoc_test_{builder,gen}.py` scripts
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (12 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 16/25] scripts: checkpatch: enable language-independent checks for Rust Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 18/25] scripts: add `generate_rust_analyzer.py` scripts Miguel Ojeda
                   ` (7 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Wedson Almeida Filho

Rust documentation tests are typically examples of usage of any
item (e.g. function, struct, module...). They are very convenient
because they are just written alongside the documentation, e.g.:

    /// Sums two numbers.
    ///
    /// # Examples
    ///
    /// ```
    /// assert_eq!(mymod::f(10, 20), 30);
    /// ```
    pub fn f(a: i32, b: i32) -> i32 {
        a + b
    }

These scripts are used to transform Rust documentation tests into
KUnit tests, so that they can be run in-kernel. In turn, this allows
us to run tests that use kernel APIs.

In particular, the test builder receives `rustdoc`-generated tests,
parses them and stores the result. Then, the test generator takes
the saved results and generates a KUnit suite where each original
documentation test is a test case.

For the moment, this is only done for the `kernel` crate, but
the plan is to generalize it for other crates and modules.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 scripts/rustdoc_test_builder.py |  59 ++++++++++++
 scripts/rustdoc_test_gen.py     | 164 ++++++++++++++++++++++++++++++++
 2 files changed, 223 insertions(+)
 create mode 100755 scripts/rustdoc_test_builder.py
 create mode 100755 scripts/rustdoc_test_gen.py

diff --git a/scripts/rustdoc_test_builder.py b/scripts/rustdoc_test_builder.py
new file mode 100755
index 000000000000..d9b47a5c54fc
--- /dev/null
+++ b/scripts/rustdoc_test_builder.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""rustdoc_test_builder - Test builder for `rustdoc`-generated tests.
+"""
+
+import json
+import pathlib
+import re
+import sys
+
+RUST_DIR = pathlib.Path("rust")
+TESTS_DIR = RUST_DIR / "test" / "doctests" / "kernel"
+
+# `[^\s]*` removes the prefix (e.g. `_doctest_main_`) plus any
+# leading path (for `O=` builds).
+MAIN_RE = re.compile(
+    r"^"
+    r"fn main\(\) { "
+    r"#\[allow\(non_snake_case\)\] "
+    r"fn ([^\s]*rust_kernel_([a-zA-Z0-9_]+))\(\) {"
+    r"$"
+)
+
+def main():
+    found_main = False
+    test_header = ""
+    test_body = ""
+    for line in sys.stdin.readlines():
+        main_match = MAIN_RE.match(line)
+        if main_match:
+            if found_main:
+                raise Exception("More than one `main` line found.")
+            found_main = True
+            function_name = main_match.group(1)
+            test_name = f"rust_kernel_doctest_{main_match.group(2)}"
+            continue
+
+        if found_main:
+            test_body += line
+        else:
+            test_header += line
+
+    if not found_main:
+        raise Exception("No `main` line found.")
+
+    call_line = f"}} {function_name}() }}"
+    if not test_body.endswith(call_line):
+        raise Exception("Unexpected end of test body.")
+    test_body = test_body[:-len(call_line)]
+
+    with open(TESTS_DIR / f"{test_name}.json", "w") as fd:
+        json.dump({
+            "name": test_name,
+            "header": test_header,
+            "body": test_body,
+        }, fd, sort_keys=True, indent=4)
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/rustdoc_test_gen.py b/scripts/rustdoc_test_gen.py
new file mode 100755
index 000000000000..ad9a94293ab5
--- /dev/null
+++ b/scripts/rustdoc_test_gen.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""rustdoc_test_gen - Generates KUnit tests from saved `rustdoc`-generated tests.
+"""
+
+import json
+import os
+import pathlib
+
+RUST_DIR = pathlib.Path("rust")
+TESTS_DIR = RUST_DIR / "test" / "doctests" / "kernel"
+
+RUST_FILE = RUST_DIR / "doctests_kernel_generated.rs"
+C_FILE = RUST_DIR / "doctests_kernel_generated_kunit.c"
+
+RUST_TEMPLATE_TEST = """
+/// Generated `{test_name}` KUnit test case from a Rust documentation test.
+#[no_mangle]
+pub fn {test_name}(__kunit_test: *mut kernel::bindings::kunit) {{
+    /// Provides mutual exclusion (see `# Implementation` notes).
+    static __KUNIT_TEST_MUTEX: kernel::sync::smutex::Mutex<()> =
+        kernel::sync::smutex::Mutex::new(());
+
+    /// Saved argument (see `# Implementation` notes).
+    static __KUNIT_TEST: core::sync::atomic::AtomicPtr<kernel::bindings::kunit> =
+        core::sync::atomic::AtomicPtr::new(core::ptr::null_mut());
+
+    let __kunit_test_mutex_guard = __KUNIT_TEST_MUTEX.lock();
+    __KUNIT_TEST.store(__kunit_test, core::sync::atomic::Ordering::SeqCst);
+
+    /// Overrides the usual [`assert!`] macro with one that calls KUnit instead.
+    macro_rules! assert {{
+        ($cond:expr $(,)?) => {{{{
+            kernel::kunit_assert!(
+                __KUNIT_TEST.load(core::sync::atomic::Ordering::SeqCst),
+                $cond
+            );
+        }}}}
+    }}
+
+    /// Overrides the usual [`assert_eq!`] macro with one that calls KUnit instead.
+    macro_rules! assert_eq {{
+        ($left:expr, $right:expr $(,)?) => {{{{
+            kernel::kunit_assert_eq!(
+                __KUNIT_TEST.load(core::sync::atomic::Ordering::SeqCst),
+                $left,
+                $right
+            );
+        }}}}
+    }}
+
+    // Many tests need the prelude, so provide it by default.
+    use kernel::prelude::*;
+
+    {test_body}
+}}
+"""
+RUST_TEMPLATE = """// SPDX-License-Identifier: GPL-2.0
+
+//! `kernel` crate documentation tests.
+
+// # Implementation
+//
+// KUnit gives us a context in the form of the `kunit_test` parameter that one
+// needs to pass back to other KUnit functions and macros.
+//
+// However, we want to keep this as an implementation detail because:
+//
+//   - Test code should not care about the implementation.
+//
+//   - Documentation looks worse if it needs to carry extra details unrelated
+//     to the piece being described.
+//
+//   - Test code should be able to define functions and call them, without
+//     having to carry the context (since functions cannot capture dynamic
+//     environment).
+//
+//   - Later on, we may want to be able to test non-kernel code (e.g. `core`,
+//     `alloc` or external crates) which likely use the standard library
+//     `assert*!` macros.
+//
+// For this reason, `static`s are used in the generated code to save the
+// argument which then gets read by the asserting macros. These macros then
+// call back into KUnit, instead of panicking.
+//
+// To avoid depending on whether KUnit allows to run tests concurrently and/or
+// reentrantly, we ensure mutual exclusion on our end. To ensure a single test
+// being killed does not trigger failure of every other test (timing out),
+// we provide different `static`s per test (which also allow for concurrent
+// execution, though KUnit runs them sequentially).
+//
+// Furthermore, since test code may create threads and assert from them, we use
+// an `AtomicPtr` to hold the context (though each test only writes once before
+// threads may be created).
+
+{rust_header}
+
+const __LOG_PREFIX: &[u8] = b"rust_kernel_doctests\\0";
+
+{rust_tests}
+"""
+
+C_TEMPLATE_TEST_DECLARATION = "void {test_name}(struct kunit *);\n"
+C_TEMPLATE_TEST_CASE = "    KUNIT_CASE({test_name}),\n"
+C_TEMPLATE = """// SPDX-License-Identifier: GPL-2.0
+/*
+ * `kernel` crate documentation tests.
+ */
+
+#include <kunit/test.h>
+
+{c_test_declarations}
+
+static struct kunit_case test_cases[] = {{
+    {c_test_cases}
+    {{ }}
+}};
+
+static struct kunit_suite test_suite = {{
+    .name = "rust_kernel_doctests",
+    .test_cases = test_cases,
+}};
+
+kunit_test_suite(test_suite);
+
+MODULE_LICENSE("GPL");
+"""
+
+def main():
+    rust_header = set()
+    rust_tests = ""
+    c_test_declarations = ""
+    c_test_cases = ""
+    for filename in sorted(os.listdir(TESTS_DIR)):
+        with open(TESTS_DIR / filename, "r") as fd:
+            test = json.load(fd)
+            for line in test["header"].strip().split("\n"):
+                rust_header.add(line)
+            rust_tests += RUST_TEMPLATE_TEST.format(
+                test_name = test["name"],
+                test_body = test["body"]
+            )
+            c_test_declarations += C_TEMPLATE_TEST_DECLARATION.format(
+                test_name = test["name"]
+            )
+            c_test_cases += C_TEMPLATE_TEST_CASE.format(
+                test_name = test["name"]
+            )
+    rust_header = sorted(rust_header)
+
+    with open(RUST_FILE, "w") as fd:
+        fd.write(RUST_TEMPLATE.format(
+            rust_header = "\n".join(rust_header).strip(),
+            rust_tests = rust_tests.strip(),
+        ))
+
+    with open(C_FILE, "w") as fd:
+        fd.write(C_TEMPLATE.format(
+            c_test_declarations=c_test_declarations.strip(),
+            c_test_cases=c_test_cases.strip(),
+        ))
+
+if __name__ == "__main__":
+    main()
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 18/25] scripts: add `generate_rust_analyzer.py` scripts
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (13 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 17/25] scripts: add `rustdoc_test_{builder,gen}.py` scripts Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 19/25] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
                   ` (6 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Finn Behrens, Wedson Almeida Filho, Gary Guo,
	Boris-Chengbiao Zhou

The `generate_rust_analyzer.py` script generates the configuration
file (`rust-project.json`) for rust-analyzer.

rust-analyzer is a modular compiler frontend for the Rust language.
It provides an LSP server which can be used in editors such as
VS Code, Emacs or Vim.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 scripts/generate_rust_analyzer.py | 134 ++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100755 scripts/generate_rust_analyzer.py

diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
new file mode 100755
index 000000000000..37c049fb18f2
--- /dev/null
+++ b/scripts/generate_rust_analyzer.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""generate_rust_analyzer - Generates the `rust-project.json` file for `rust-analyzer`.
+"""
+
+import argparse
+import json
+import logging
+import pathlib
+import sys
+
+def generate_crates(srctree, objtree, sysroot_src):
+    # Generate the configuration list.
+    cfg = []
+    with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
+        for line in fd:
+            line = line.replace("--cfg=", "")
+            line = line.replace("\n", "")
+            cfg.append(line)
+
+    # Now fill the crates list -- dependencies need to come first.
+    #
+    # Avoid O(n^2) iterations by keeping a map of indexes.
+    crates = []
+    crates_indexes = {}
+
+    def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
+        crates_indexes[display_name] = len(crates)
+        crates.append({
+            "display_name": display_name,
+            "root_module": str(root_module),
+            "is_workspace_member": is_workspace_member,
+            "is_proc_macro": is_proc_macro,
+            "deps": [{"crate": crates_indexes[dep], "name": dep} for dep in deps],
+            "cfg": cfg,
+            "edition": "2021",
+            "env": {
+                "RUST_MODFILE": "This is only for rust-analyzer"
+            }
+        })
+
+    # First, the ones in `rust/` since they are a bit special.
+    append_crate(
+        "core",
+        sysroot_src / "core" / "src" / "lib.rs",
+        [],
+        is_workspace_member=False,
+    )
+
+    append_crate(
+        "compiler_builtins",
+        srctree / "rust" / "compiler_builtins.rs",
+        [],
+    )
+
+    append_crate(
+        "alloc",
+        srctree / "rust" / "alloc" / "lib.rs",
+        ["core", "compiler_builtins"],
+    )
+
+    append_crate(
+        "macros",
+        srctree / "rust" / "macros" / "lib.rs",
+        [],
+        is_proc_macro=True,
+    )
+    crates[-1]["proc_macro_dylib_path"] = "rust/libmacros.so"
+
+    append_crate(
+        "build_error",
+        srctree / "rust" / "build_error.rs",
+        ["core", "compiler_builtins"],
+    )
+
+    append_crate(
+        "kernel",
+        srctree / "rust" / "kernel" / "lib.rs",
+        ["core", "alloc", "macros", "build_error"],
+        cfg=cfg,
+    )
+    crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True))
+    crates[-1]["source"] = {
+        "include_dirs": [
+            str(srctree / "rust" / "kernel"),
+            str(objtree / "rust")
+        ],
+        "exclude_dirs": [],
+    }
+
+    # Then, the rest outside of `rust/`.
+    #
+    # We explicitly mention the top-level folders we want to cover.
+    for folder in ("samples", "drivers"):
+        for path in (srctree / folder).rglob("*.rs"):
+            logging.info("Checking %s", path)
+            name = path.name.replace(".rs", "")
+
+            # Skip those that are not crate roots.
+            if f"{name}.o" not in open(path.parent / "Makefile").read():
+                continue
+
+            logging.info("Adding %s", name)
+            append_crate(
+                name,
+                path,
+                ["core", "alloc", "kernel"],
+                cfg=cfg,
+            )
+
+    return crates
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument("srctree", type=pathlib.Path)
+    parser.add_argument("objtree", type=pathlib.Path)
+    parser.add_argument("sysroot_src", type=pathlib.Path)
+    args = parser.parse_args()
+
+    logging.basicConfig(
+        format="[%(asctime)s] [%(levelname)s] %(message)s",
+        level=logging.INFO if args.verbose else logging.WARNING
+    )
+
+    rust_project = {
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src),
+        "sysroot_src": str(args.sysroot_src),
+    }
+
+    json.dump(rust_project, sys.stdout, sort_keys=True, indent=4)
+
+if __name__ == "__main__":
+    main()
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 19/25] scripts: decode_stacktrace: demangle Rust symbols
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (14 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 18/25] scripts: add `generate_rust_analyzer.py` scripts Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 20/25] docs: add Rust documentation Miguel Ojeda
                   ` (5 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Kees Cook, Alex Gaynor, Wedson Almeida Filho

Recent versions of both Binutils (`c++filt`) and LLVM (`llvm-cxxfilt`)
provide Rust v0 mangling support.

Reviewed-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
I would like to use this patch for discussing the demangling topic.

The last discussion took place in v6:

    https://lore.kernel.org/lkml/20220507052451.12890-18-ojeda@kernel.org/

The following discusses the different approaches we could take.


# Leave demangling to userspace

This is the easiest and less invasive approach, the one implemented
by this patch.

The `decode_stacktrace.sh` script is already needed to map
the offsets to the source code. Therefore, we could also take
the chance to demangle the symbols here.

With this approach, we do not need to introduce any change in the
`vsprintf` machinery and we minimize the risk of breaking user tools.

Note that, if we take this approach, it is likely we want to ask
for a minimum version of either of the tools (since there may be
users of the script that do not have recent enough toolchains).


# Demangling in kernelspace on-the-fly

That is, at backtrace print time, we demangle the Rust symbols.

The size of the code that would be needed is fairly small; around
5 KiB using the "official" library (written in Rust), e.g.:

    text    data    bss     dec      hex    filename
    7799976 1689820 2129920 11619716 b14d84 vmlinux
    7801111 1693916 2129920 11624947 b161f3 vmlinux + demangling

We can remove a few bits from the official library, e.g. punycode
support that we do not need (all our identifiers will be ASCII),
but it does not make a substantial difference.

The official library performs the demangling without requiring
allocations. However, of course, it will increased our stack usage
and complexity, specially considering a stack dump may be requested
in not ideal conditions.

Furthermore, this approach (and the ones below) likely require adding
a new `%p` specifier (or a new modifier to existing ones) if we do
not want to affect non-backtrace uses of the `B`/`S` ones. Also,
it is unclear whether we should write the demangled versions in an
extra, different line or replace the real symbol -- we could be
breaking user tools relying on parsing backtraces (e.g. our own
`decode_stacktrace.sh`). For instance, they could be relying on
having real symbols there, or may break due to e.g. spaces.


# Demangling at compile-time

This implies having kallsyms demangle all the Rust symbols.

The size of this data is around the same order of magnitude of the
non-demangled ones. However, this is notably more than the demangling
code (see previous point), e.g. 120 KiB (uncompressed) in a
small kernel.

This approach also brings the same concerns regarding modifying
the backtrace printing (see previous point).


# Demangling at compile-time and substituting symbols by hashes

One variation of the previous alternative is avoiding the mangled
names inside the kernel, by hashing them. This would avoid having
to support "big symbols" and would also reduce the size of the
kallsyms tables, while still allowing to link modules.

However, if we do not have the real symbols around, then we do not
have the possibility of providing both the mangled and demangled
versions in the backtrace, which brings us back to the issues
related to breaking userspace tools. There are also other places
other than backtraces using "real" symbols that users may be
relying on, such as `/proc/*/stack`.


 scripts/decode_stacktrace.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index 5fbad61fe490..f3c7b506d440 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -8,6 +8,14 @@ usage() {
 	echo "	$0 -r <release> | <vmlinux> [<base path>|auto] [<modules path>]"
 }
 
+# Try to find a Rust demangler
+if type llvm-cxxfilt >/dev/null 2>&1 ; then
+	cppfilt=llvm-cxxfilt
+elif type c++filt >/dev/null 2>&1 ; then
+	cppfilt=c++filt
+	cppfilt_opts=-i
+fi
+
 if [[ $1 == "-r" ]] ; then
 	vmlinux=""
 	basepath="auto"
@@ -169,6 +177,12 @@ parse_symbol() {
 	# In the case of inlines, move everything to same line
 	code=${code//$'\n'/' '}
 
+	# Demangle if the name looks like a Rust symbol and if
+	# we got a Rust demangler
+	if [[ $name =~ ^_R && $cppfilt != "" ]] ; then
+		name=$("$cppfilt" "$cppfilt_opts" "$name")
+	fi
+
 	# Replace old address with pretty line numbers
 	symbol="$segment$name ($code)"
 }
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 20/25] docs: add Rust documentation
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (15 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 19/25] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
                   ` (4 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Kees Cook, Alex Gaynor, Finn Behrens, Adam Bratschi-Kaye,
	Wedson Almeida Filho, Michael Ellerman, Sven Van Asbroeck,
	Wu XiangCheng, Gary Guo, Boris-Chengbiao Zhou, Yuki Okushi,
	Wei Liu, Daniel Xu, Julian Merkle, Jonathan Corbet,
	Masahiro Yamada, Michal Marek, Nick Desaulniers, linux-doc,
	linux-kbuild

Most of the documentation for Rust is written within the source code
itself, as it is idiomatic for Rust projects. This applies to both
the shared infrastructure at `rust/` as well as any other Rust module
(e.g. drivers) written across the kernel.

However, these documents contain general information that does not
fit particularly well in the source code, like the Quick Start guide.

It also contains an asset (SVG logo) used for the `rustdoc` target
and a few other small changes elsewhere in the documentation folder.

Reviewed-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Wu XiangCheng <bobwxc@email.cn>
Signed-off-by: Wu XiangCheng <bobwxc@email.cn>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Co-developed-by: Yuki Okushi <jtitor@2k36.org>
Signed-off-by: Yuki Okushi <jtitor@2k36.org>
Co-developed-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Co-developed-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Co-developed-by: Julian Merkle <me@jvmerkle.de>
Signed-off-by: Julian Merkle <me@jvmerkle.de>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 Documentation/doc-guide/kernel-doc.rst     |   3 +
 Documentation/index.rst                    |   1 +
 Documentation/kbuild/kbuild.rst            |  17 ++
 Documentation/kbuild/makefiles.rst         |  50 ++++-
 Documentation/process/changes.rst          |  41 ++++
 Documentation/rust/arch-support.rst        |  25 +++
 Documentation/rust/coding-guidelines.rst   | 216 +++++++++++++++++++
 Documentation/rust/general-information.rst |  79 +++++++
 Documentation/rust/index.rst               |  22 ++
 Documentation/rust/quick-start.rst         | 232 +++++++++++++++++++++
 10 files changed, 682 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/rust/arch-support.rst
 create mode 100644 Documentation/rust/coding-guidelines.rst
 create mode 100644 Documentation/rust/general-information.rst
 create mode 100644 Documentation/rust/index.rst
 create mode 100644 Documentation/rust/quick-start.rst

diff --git a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst
index 79aaa55d6bcf..cde7aa67e76f 100644
--- a/Documentation/doc-guide/kernel-doc.rst
+++ b/Documentation/doc-guide/kernel-doc.rst
@@ -11,6 +11,9 @@ when it is embedded in source files.
    reasons. The kernel source contains tens of thousands of kernel-doc
    comments. Please stick to the style described here.
 
+.. note:: kernel-doc does not cover Rust code: please see
+   Documentation/rust/general-information.rst instead.
+
 The kernel-doc structure is extracted from the comments, and proper
 `Sphinx C Domain`_ function and type descriptions with anchors are
 generated from them. The descriptions are filtered for special kernel-doc
diff --git a/Documentation/index.rst b/Documentation/index.rst
index 1988c19d9daf..ee639a500278 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -82,6 +82,7 @@ merged much easier.
    maintainer/index
    fault-injection/index
    livepatch/index
+   rust/index
 
 
 Kernel API documentation
diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
index ef19b9c13523..08f575e6236c 100644
--- a/Documentation/kbuild/kbuild.rst
+++ b/Documentation/kbuild/kbuild.rst
@@ -48,6 +48,10 @@ KCFLAGS
 -------
 Additional options to the C compiler (for built-in and modules).
 
+KRUSTFLAGS
+----------
+Additional options to the Rust compiler (for built-in and modules).
+
 CFLAGS_KERNEL
 -------------
 Additional options for $(CC) when used to compile
@@ -57,6 +61,15 @@ CFLAGS_MODULE
 -------------
 Additional module specific options to use for $(CC).
 
+RUSTFLAGS_KERNEL
+----------------
+Additional options for $(RUSTC) when used to compile
+code that is compiled as built-in.
+
+RUSTFLAGS_MODULE
+----------------
+Additional module specific options to use for $(RUSTC).
+
 LDFLAGS_MODULE
 --------------
 Additional options used for $(LD) when linking modules.
@@ -69,6 +82,10 @@ HOSTCXXFLAGS
 ------------
 Additional flags to be passed to $(HOSTCXX) when building host programs.
 
+HOSTRUSTFLAGS
+-------------
+Additional flags to be passed to $(HOSTRUSTC) when building host programs.
+
 HOSTLDFLAGS
 -----------
 Additional flags to be passed when linking host programs.
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 11a296e52d68..5ea1e72d89c8 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -29,8 +29,9 @@ This document describes the Linux kernel Makefiles.
 	   --- 4.1 Simple Host Program
 	   --- 4.2 Composite Host Programs
 	   --- 4.3 Using C++ for host programs
-	   --- 4.4 Controlling compiler options for host programs
-	   --- 4.5 When host programs are actually built
+	   --- 4.4 Using Rust for host programs
+	   --- 4.5 Controlling compiler options for host programs
+	   --- 4.6 When host programs are actually built
 
 	=== 5 Userspace Program support
 	   --- 5.1 Simple Userspace Program
@@ -835,7 +836,24 @@ Both possibilities are described in the following.
 		qconf-cxxobjs := qconf.o
 		qconf-objs    := check.o
 
-4.4 Controlling compiler options for host programs
+4.4 Using Rust for host programs
+--------------------------------
+
+	Kbuild offers support for host programs written in Rust. However,
+	since a Rust toolchain is not mandatory for kernel compilation,
+	it may only be used in scenarios where Rust is required to be
+	available (e.g. when  ``CONFIG_RUST`` is enabled).
+
+	Example::
+
+		hostprogs     := target
+		target-rust   := y
+
+	Kbuild will compile ``target`` using ``target.rs`` as the crate root,
+	located in the same directory as the ``Makefile``. The crate may
+	consist of several source files (see ``samples/rust/hostprogs``).
+
+4.5 Controlling compiler options for host programs
 --------------------------------------------------
 
 	When compiling host programs, it is possible to set specific flags.
@@ -867,7 +885,7 @@ Both possibilities are described in the following.
 	When linking qconf, it will be passed the extra option
 	"-L$(QTDIR)/lib".
 
-4.5 When host programs are actually built
+4.6 When host programs are actually built
 -----------------------------------------
 
 	Kbuild will only build host-programs when they are referenced
@@ -1181,6 +1199,17 @@ When kbuild executes, the following steps are followed (roughly):
 	The first example utilises the trick that a config option expands
 	to 'y' when selected.
 
+    KBUILD_RUSTFLAGS
+	$(RUSTC) compiler flags
+
+	Default value - see top level Makefile
+	Append or modify as required per architecture.
+
+	Often, the KBUILD_RUSTFLAGS variable depends on the configuration.
+
+	Note that target specification file generation (for ``--target``)
+	is handled in ``scripts/generate_rust_target.rs``.
+
     KBUILD_AFLAGS_KERNEL
 	Assembler options specific for built-in
 
@@ -1208,6 +1237,19 @@ When kbuild executes, the following steps are followed (roughly):
 	are used for $(CC).
 	From commandline CFLAGS_MODULE shall be used (see kbuild.rst).
 
+    KBUILD_RUSTFLAGS_KERNEL
+	$(RUSTC) options specific for built-in
+
+	$(KBUILD_RUSTFLAGS_KERNEL) contains extra Rust compiler flags used to
+	compile resident kernel code.
+
+    KBUILD_RUSTFLAGS_MODULE
+	Options for $(RUSTC) when building modules
+
+	$(KBUILD_RUSTFLAGS_MODULE) is used to add arch-specific options that
+	are used for $(RUSTC).
+	From commandline RUSTFLAGS_MODULE shall be used (see kbuild.rst).
+
     KBUILD_LDFLAGS_MODULE
 	Options for $(LD) when linking modules
 
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index a337e8eabfe1..a886ac497266 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -31,6 +31,8 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
+Rust (optional)        1.60.0           rustc --version
+bindgen (optional)     0.56.0           bindgen --version
 GNU make               3.81             make --version
 binutils               2.23             ld -v
 flex                   2.5.35           flex --version
@@ -78,6 +80,29 @@ kernels. Older releases aren't guaranteed to work, and we may drop workarounds
 from the kernel that were used to support older versions. Please see additional
 docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`.
 
+Rust (optional)
+---------------
+
+A particular version of the Rust toolchain is required. Newer versions may or
+may not work because the kernel depends on some unstable Rust features, for
+the moment.
+
+Each Rust toolchain comes with several "components", some of which are required
+(like ``rustc``) and some that are optional. The ``rust-src`` component (which
+is optional) needs to be installed to build the kernel. Other components are
+useful for developing.
+
+Please see Documentation/rust/quick-start.rst for instructions on how to
+satisfy the build requirements of Rust support. In particular, the ``Makefile``
+target ``rustavailable`` is useful to check why the Rust toolchain may not
+be detected.
+
+bindgen (optional)
+------------------
+
+``bindgen`` is used to generate the Rust bindings to the C side of the kernel.
+It depends on ``libclang``.
+
 Make
 ----
 
@@ -340,6 +365,12 @@ Sphinx
 Please see :ref:`sphinx_install` in :ref:`Documentation/doc-guide/sphinx.rst <sphinxdoc>`
 for details about Sphinx requirements.
 
+rustdoc
+-------
+
+``rustdoc`` is used to generate the documentation for Rust code. Please see
+Documentation/rust/general-information.rst for more information.
+
 Getting updated software
 ========================
 
@@ -356,6 +387,16 @@ Clang/LLVM
 
 - :ref:`Getting LLVM <getting_llvm>`.
 
+Rust
+----
+
+- Documentation/rust/quick-start.rst.
+
+bindgen
+-------
+
+- Documentation/rust/quick-start.rst.
+
 Make
 ----
 
diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst
new file mode 100644
index 000000000000..79ebad889720
--- /dev/null
+++ b/Documentation/rust/arch-support.rst
@@ -0,0 +1,25 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Arch Support
+============
+
+Currently, the Rust compiler (``rustc``) uses LLVM for code generation,
+which limits the supported architectures that can be targeted. In addition,
+support for building the kernel with LLVM/Clang varies (please see
+Documentation/kbuild/llvm.rst). This support is needed for ``bindgen``
+which uses ``libclang``.
+
+Below is a general summary of architectures that currently work. Level of
+support corresponds to ``S`` values in the ``MAINTAINERS`` file.
+
+============  ================  ==============================================
+Architecture  Level of support  Constraints
+============  ================  ==============================================
+``arm``       Maintained        ``armv6`` and compatible only,
+                                ``RUST_OPT_LEVEL >= 2``.
+``arm64``     Maintained        None.
+``powerpc``   Maintained        ``ppc64le`` only, ``RUST_OPT_LEVEL < 2``
+                                requires ``CONFIG_THREAD_SHIFT=15``.
+``riscv``     Maintained        ``riscv64`` only.
+``x86``       Maintained        ``x86_64`` only.
+============  ================  ==============================================
diff --git a/Documentation/rust/coding-guidelines.rst b/Documentation/rust/coding-guidelines.rst
new file mode 100644
index 000000000000..aa8ed082613e
--- /dev/null
+++ b/Documentation/rust/coding-guidelines.rst
@@ -0,0 +1,216 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Coding Guidelines
+=================
+
+This document describes how to write Rust code in the kernel.
+
+
+Style & formatting
+------------------
+
+The code should be formatted using ``rustfmt``. In this way, a person
+contributing from time to time to the kernel does not need to learn and
+remember one more style guide. More importantly, reviewers and maintainers
+do not need to spend time pointing out style issues anymore, and thus
+less patch roundtrips may be needed to land a change.
+
+.. note:: Conventions on comments and documentation are not checked by
+  ``rustfmt``. Thus those are still needed to be taken care of.
+
+The default settings of ``rustfmt`` are used. This means the idiomatic Rust
+style is followed. For instance, 4 spaces are used for indentation rather
+than tabs.
+
+It is convenient to instruct editors/IDEs to format while typing,
+when saving or at commit time. However, if for some reason reformatting
+the entire kernel Rust sources is needed at some point, the following can be
+run::
+
+	make LLVM=1 rustfmt
+
+It is also possible to check if everything is formatted (printing a diff
+otherwise), for instance for a CI, with::
+
+	make LLVM=1 rustfmtcheck
+
+Like ``clang-format`` for the rest of the kernel, ``rustfmt`` works on
+individual files, and does not require a kernel configuration. Sometimes it may
+even work with broken code.
+
+
+Comments
+--------
+
+"Normal" comments (i.e. ``//``, rather than code documentation which starts
+with ``///`` or ``//!``) are written in Markdown the same way as documentation
+comments are, even though they will not be rendered. This improves consistency,
+simplifies the rules and allows to move content between the two kinds of
+comments more easily. For instance:
+
+.. code-block:: rust
+
+	// `object` is ready to be handled now.
+	f(object);
+
+Furthermore, just like documentation, comments are capitalized at the beginning
+of a sentence and ended with a period (even if it is a single sentence). This
+includes ``// SAFETY:``, ``// TODO:`` and other "tagged" comments, e.g.:
+
+.. code-block:: rust
+
+	// FIXME: The error should be handled properly.
+
+Comments should not be used for documentation purposes: comments are intended
+for implementation details, not users. This distinction is useful even if the
+reader of the source file is both an implementor and a user of an API. In fact,
+sometimes it is useful to use both comments and documentation at the same time.
+For instance, for a ``TODO`` list or to comment on the documentation itself.
+For the latter case, comments can be inserted in the middle; that is, closer to
+the line of documentation to be commented. For any other case, comments are
+written after the documentation, e.g.:
+
+.. code-block:: rust
+
+	/// Returns a new [`Foo`].
+	///
+	/// # Examples
+	///
+	// TODO: Find a better example.
+	/// ```
+	/// let foo = f(42);
+	/// ```
+	// FIXME: Use fallible approach.
+	pub fn f(x: i32) -> Foo {
+	    // ...
+	}
+
+One special kind of comments are the ``// SAFETY:`` comments. These must appear
+before every ``unsafe`` block, and they explain why the code inside the block is
+correct/sound, i.e. why it cannot trigger undefined behavior in any case, e.g.:
+
+.. code-block:: rust
+
+	// SAFETY: `p` is valid by the safety requirements.
+	unsafe { *p = 0; }
+
+``// SAFETY:`` comments are not to be confused with the ``# Safety`` sections
+in code documentation. ``# Safety`` sections specify the contract that callers
+(for functions) or implementors (for traits) need to abide by. ``// SAFETY:``
+comments show why a call (for functions) or implementation (for traits) actually
+respects the preconditions stated in a ``# Safety`` section or the language
+reference.
+
+
+Code documentation
+------------------
+
+Rust kernel code is not documented like C kernel code (i.e. via kernel-doc).
+Instead, the usual system for documenting Rust code is used: the ``rustdoc``
+tool, which uses Markdown (a lightweight markup language).
+
+To learn Markdown, there are many guides available out there. For instance,
+the one at:
+
+	https://commonmark.org/help/
+
+This is how a well-documented Rust function may look like:
+
+.. code-block:: rust
+
+	/// Returns the contained [`Some`] value, consuming the `self` value,
+	/// without checking that the value is not [`None`].
+	///
+	/// # Safety
+	///
+	/// Calling this method on [`None`] is *[undefined behavior]*.
+	///
+	/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+	///
+	/// # Examples
+	///
+	/// ```
+	/// let x = Some("air");
+	/// assert_eq!(unsafe { x.unwrap_unchecked() }, "air");
+	/// ```
+	pub unsafe fn unwrap_unchecked(self) -> T {
+	    match self {
+	        Some(val) => val,
+
+	        // SAFETY: The safety contract must be upheld by the caller.
+	        None => unsafe { hint::unreachable_unchecked() },
+	    }
+	}
+
+This example showcases a few ``rustdoc`` features and some conventions followed
+in the kernel:
+
+  - The first paragraph must be a single sentence briefly describing what
+    the documented item does. Further explanations must go in extra paragraphs.
+
+  - Unsafe functions must document their safety preconditions under
+    a ``# Safety`` section.
+
+  - While not shown here, if a function may panic, the conditions under which
+    that happens must be described under a ``# Panics`` section.
+
+    Please note that panicking should be very rare and used only with a good
+    reason. In almost all cases, a fallible approach should be used, typically
+    returning a ``Result``.
+
+  - If providing examples of usage would help readers, they must be written in
+    a section called ``# Examples``.
+
+  - Rust items (functions, types, constants...) must be linked appropriately
+    (``rustdoc`` will create a link automatically).
+
+  - Any ``unsafe`` block must be preceded by a ``// SAFETY:`` comment
+    describing why the code inside is sound.
+
+    While sometimes the reason might look trivial and therefore unneeded,
+    writing these comments is not just a good way of documenting what has been
+    taken into account, but most importantly, it provides a way to know that
+    there are no *extra* implicit constraints.
+
+To learn more about how to write documentation for Rust and extra features,
+please take a look at the ``rustdoc`` book at:
+
+	https://doc.rust-lang.org/rustdoc/how-to-write-documentation.html
+
+
+Naming
+------
+
+Rust kernel code follows the usual Rust naming conventions:
+
+	https://rust-lang.github.io/api-guidelines/naming.html
+
+When existing C concepts (e.g. macros, functions, objects...) are wrapped into
+a Rust abstraction, a name as close as reasonably possible to the C side should
+be used in order to avoid confusion and to improve readability when switching
+back and forth between the C and Rust sides. For instance, macros such as
+``pr_info`` from C are named the same in the Rust side.
+
+Having said that, casing should be adjusted to follow the Rust naming
+conventions, and namespacing introduced by modules and types should not be
+repeated in the item names. For instance, when wrapping constants like:
+
+.. code-block:: c
+
+	#define GPIO_LINE_DIRECTION_IN	0
+	#define GPIO_LINE_DIRECTION_OUT	1
+
+The equivalent in Rust may look like (ignoring documentation):
+
+.. code-block:: rust
+
+	pub mod gpio {
+	    pub enum LineDirection {
+	        In = bindings::GPIO_LINE_DIRECTION_IN as _,
+	        Out = bindings::GPIO_LINE_DIRECTION_OUT as _,
+	    }
+	}
+
+That is, the equivalent of ``GPIO_LINE_DIRECTION_IN`` would be referred to as
+``gpio::LineDirection::In``. In particular, it should not be named
+``gpio::gpio_line_direction::GPIO_LINE_DIRECTION_IN``.
diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
new file mode 100644
index 000000000000..49029ee82e55
--- /dev/null
+++ b/Documentation/rust/general-information.rst
@@ -0,0 +1,79 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+General Information
+===================
+
+This document contains useful information to know when working with
+the Rust support in the kernel.
+
+
+Code documentation
+------------------
+
+Rust kernel code is documented using ``rustdoc``, its built-in documentation
+generator.
+
+The generated HTML docs include integrated search, linked items (e.g. types,
+functions, constants), source code, etc. They may be read at (TODO: link when
+in mainline and generated alongside the rest of the documentation):
+
+	http://kernel.org/
+
+The docs can also be easily generated and read locally. This is quite fast
+(same order as compiling the code itself) and no special tools or environment
+are needed. This has the added advantage that they will be tailored to
+the particular kernel configuration used. To generate them, use the ``rustdoc``
+target with the same invocation used for compilation, e.g.::
+
+	make LLVM=1 rustdoc
+
+To read the docs locally in your web browser, run e.g.::
+
+	xdg-open rust/doc/kernel/index.html
+
+To learn about how to write the documentation, please see coding-guidelines.rst.
+
+
+Extra lints
+-----------
+
+While ``rustc`` is a very helpful compiler, some extra lints and analyses are
+available via ``clippy``, a Rust linter. To enable it, pass ``CLIPPY=1`` to
+the same invocation used for compilation, e.g.::
+
+	make LLVM=1 CLIPPY=1
+
+Please note that Clippy may change code generation, thus it should not be
+enabled while building a production kernel.
+
+
+Abstractions vs. bindings
+-------------------------
+
+Abstractions are Rust code wrapping kernel functionality from the C side.
+
+In order to use functions and types from the C side, bindings are created.
+Bindings are the declarations for Rust of those functions and types from
+the C side.
+
+For instance, one may write a ``Mutex`` abstraction in Rust which wraps
+a ``struct mutex`` from the C side and calls its functions through the bindings.
+
+Abstractions are not available for all the kernel internal APIs and concepts,
+but it is intended that coverage is expanded as time goes on. "Leaf" modules
+(e.g. drivers) should not use the C bindings directly. Instead, subsystems
+should provide as-safe-as-possible abstractions as needed.
+
+
+Conditional compilation
+-----------------------
+
+Rust code has access to conditional compilation based on the kernel
+configuration:
+
+.. code-block:: rust
+
+	#[cfg(CONFIG_X)]       // Enabled               (`y` or `m`)
+	#[cfg(CONFIG_X="y")]   // Enabled as a built-in (`y`)
+	#[cfg(CONFIG_X="m")]   // Enabled as a module   (`m`)
+	#[cfg(not(CONFIG_X))]  // Disabled
diff --git a/Documentation/rust/index.rst b/Documentation/rust/index.rst
new file mode 100644
index 000000000000..4ae8c66b94fa
--- /dev/null
+++ b/Documentation/rust/index.rst
@@ -0,0 +1,22 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Rust
+====
+
+Documentation related to Rust within the kernel. To start using Rust
+in the kernel, please read the quick-start.rst guide.
+
+.. toctree::
+    :maxdepth: 1
+
+    quick-start
+    general-information
+    coding-guidelines
+    arch-support
+
+.. only::  subproject and html
+
+   Indices
+   =======
+
+   * :ref:`genindex`
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
new file mode 100644
index 000000000000..13b7744b1e27
--- /dev/null
+++ b/Documentation/rust/quick-start.rst
@@ -0,0 +1,232 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Quick Start
+===========
+
+This document describes how to get started with kernel development in Rust.
+
+
+Requirements: Building
+----------------------
+
+This section explains how to fetch the tools needed for building.
+
+Some of these requirements might be available from Linux distributions
+under names like ``rustc``, ``rust-src``, ``rust-bindgen``, etc. However,
+at the time of writing, they are likely not to be recent enough unless
+the distribution tracks the latest releases.
+
+To easily check whether the requirements are met, the following target
+can be used::
+
+	make LLVM=1 rustavailable
+
+This triggers the same logic used by Kconfig to determine whether
+``RUST_IS_AVAILABLE`` should be enabled; but it also explains why not
+if that is the case.
+
+
+rustc
+*****
+
+A particular version of the Rust compiler is required. Newer versions may or
+may not work because, for the moment, the kernel depends on some unstable
+Rust features.
+
+If ``rustup`` is being used, enter the checked out source code directory
+and run::
+
+	rustup override set $(scripts/min-tool-version.sh rustc)
+
+Otherwise, fetch a standalone installer or install ``rustup`` from:
+
+	https://www.rust-lang.org
+
+
+Rust standard library source
+****************************
+
+The Rust standard library source is required because the build system will
+cross-compile ``core`` and ``alloc``.
+
+If ``rustup`` is being used, run::
+
+	rustup component add rust-src
+
+The components are installed per toolchain, thus upgrading the Rust compiler
+version later on requires re-adding the component.
+
+Otherwise, if a standalone installer is used, the Rust repository may be cloned
+into the installation folder of the toolchain::
+
+	git clone --recurse-submodules \
+		--branch $(scripts/min-tool-version.sh rustc) \
+		https://github.com/rust-lang/rust \
+		$(rustc --print sysroot)/lib/rustlib/src/rust
+
+In this case, upgrading the Rust compiler version later on requires manually
+updating this clone.
+
+
+libclang
+********
+
+``libclang`` (part of LLVM) is used by ``bindgen`` to understand the C code
+in the kernel, which means LLVM needs to be installed; like when the kernel
+is compiled with ``CC=clang`` or ``LLVM=1``.
+
+Linux distributions are likely to have a suitable one available, so it is
+best to check that first.
+
+There are also some binaries for several systems and architectures uploaded at:
+
+	https://releases.llvm.org/download.html
+
+Otherwise, building LLVM takes quite a while, but it is not a complex process:
+
+	https://llvm.org/docs/GettingStarted.html#getting-the-source-code-and-building-llvm
+
+Please see Documentation/kbuild/llvm.rst for more information and further ways
+to fetch pre-built releases and distribution packages.
+
+
+bindgen
+*******
+
+The bindings to the C side of the kernel are generated at build time using
+the ``bindgen`` tool. A particular version is required.
+
+Install it via (note that this will download and build the tool from source)::
+
+	cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen
+
+
+Requirements: Developing
+------------------------
+
+This section explains how to fetch the tools needed for developing. That is,
+they are not needed when just building the kernel.
+
+
+rustfmt
+*******
+
+The ``rustfmt`` tool is used to automatically format all the Rust kernel code,
+including the generated C bindings (for details, please see
+coding-guidelines.rst).
+
+If ``rustup`` is being used, its ``default`` profile already installs the tool,
+thus nothing needs to be done. If another profile is being used, the component
+can be installed manually::
+
+	rustup component add rustfmt
+
+The standalone installers also come with ``rustfmt``.
+
+
+clippy
+******
+
+``clippy`` is a Rust linter. Running it provides extra warnings for Rust code.
+It can be run by passing ``CLIPPY=1`` to ``make`` (for details, please see
+general-information.rst).
+
+If ``rustup`` is being used, its ``default`` profile already installs the tool,
+thus nothing needs to be done. If another profile is being used, the component
+can be installed manually::
+
+	rustup component add clippy
+
+The standalone installers also come with ``clippy``.
+
+
+cargo
+*****
+
+``cargo`` is the Rust native build system. It is currently required to run
+the tests since it is used to build a custom standard library that contains
+the facilities provided by the custom ``alloc`` in the kernel. The tests can
+be run using the ``rusttest`` Make target.
+
+If ``rustup`` is being used, all the profiles already install the tool,
+thus nothing needs to be done.
+
+The standalone installers also come with ``cargo``.
+
+
+rustdoc
+*******
+
+``rustdoc`` is the documentation tool for Rust. It generates pretty HTML
+documentation for Rust code (for details, please see
+general-information.rst).
+
+``rustdoc`` is also used to test the examples provided in documented Rust code
+(called doctests or documentation tests). The ``rusttest`` Make target uses
+this feature.
+
+If ``rustup`` is being used, all the profiles already install the tool,
+thus nothing needs to be done.
+
+The standalone installers also come with ``rustdoc``.
+
+
+rust-analyzer
+*************
+
+The `rust-analyzer <https://rust-analyzer.github.io/>`_ language server can
+be used with many editors to enable syntax highlighting, completion, go to
+definition, and other features.
+
+``rust-analyzer`` needs a configuration file, ``rust-project.json``, which
+can be generated by the ``rust-analyzer`` Make target.
+
+
+Configuration
+-------------
+
+``Rust support`` (``CONFIG_RUST``) needs to be enabled in the ``General setup``
+menu. The option is only shown if a suitable Rust toolchain is found (see
+above), as long as the other requirements are met. In turn, this will make
+visible the rest of options that depend on Rust.
+
+Afterwards, go to::
+
+	Kernel hacking
+	    -> Sample kernel code
+	        -> Rust samples
+
+And enable some sample modules either as built-in or as loadable.
+
+
+Building
+--------
+
+Building a kernel with a complete LLVM toolchain is the best supported setup
+at the moment. That is::
+
+	make LLVM=1
+
+For architectures that do not support a full LLVM toolchain, use::
+
+	make CC=clang
+
+Using GCC also works for some configurations, but it is very experimental at
+the moment.
+
+
+Hacking
+-------
+
+To dive deeper, take a look at the source code of the samples
+at ``samples/rust/``, the Rust support code under ``rust/`` and
+the ``Rust hacking`` menu under ``Kernel hacking``.
+
+If GDB/Binutils is used and Rust symbols are not getting demangled, the reason
+is the toolchain does not support Rust's new v0 mangling scheme yet.
+There are a few ways out:
+
+  - Install a newer release (GDB >= 10.2, Binutils >= 2.36).
+
+  - Some versions of GDB (e.g. vanilla GDB 10.1) are able to use
+    the pre-demangled names embedded in the debug info (``CONFIG_DEBUG_INFO``).
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 21/25] Kbuild: add Rust support
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (16 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 20/25] docs: add Rust documentation Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23 18:44   ` Nick Desaulniers
                     ` (2 more replies)
  2022-05-23  2:01 ` [PATCH v7 22/25] samples: add Rust examples Miguel Ojeda
                   ` (3 subsequent siblings)
  21 siblings, 3 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Finn Behrens, Adam Bratschi-Kaye,
	Wedson Almeida Filho, Michael Ellerman, Sven Van Asbroeck,
	Gary Guo, Boris-Chengbiao Zhou, Boqun Feng, Douglas Su,
	Dariusz Sosnowski, Antonio Terceiro, Daniel Xu, Miguel Cano,
	David Gow, Masahiro Yamada, Michal Marek, Nick Desaulniers,
	Russell King, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Paul Walmsley,
	Palmer Dabbelt, Albert Ou, Richard Weinberger, Anton Ivanov,
	Johannes Berg, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	Dave Hansen, x86, H. Peter Anvin, linux-kbuild, linux-arm-kernel,
	linuxppc-dev, linux-riscv, linux-um

Having all the new files in place, we now enable Rust support
in the build system, including `Kconfig` entries related to Rust,
the Rust configuration printer, the target specification
generation script, the version detection script and a few
other bits.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Douglas Su <d0u9.su@outlook.com>
Signed-off-by: Douglas Su <d0u9.su@outlook.com>
Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Co-developed-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Co-developed-by: Miguel Cano <macanroj@gmail.com>
Signed-off-by: Miguel Cano <macanroj@gmail.com>
Co-developed-by: David Gow <davidgow@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 .gitignore                                   |   5 +
 .rustfmt.toml                                |  12 +
 Makefile                                     | 175 +++++++-
 arch/Kconfig                                 |   6 +
 arch/arm/Kconfig                             |   1 +
 arch/arm64/Kconfig                           |   1 +
 arch/powerpc/Kconfig                         |   1 +
 arch/riscv/Kconfig                           |   1 +
 arch/riscv/Makefile                          |   5 +
 arch/um/Kconfig                              |   1 +
 arch/x86/Kconfig                             |   1 +
 arch/x86/Makefile                            |  14 +
 init/Kconfig                                 |  45 ++-
 lib/Kconfig.debug                            | 155 ++++++++
 rust/.gitignore                              |  10 +
 rust/Makefile                                | 398 +++++++++++++++++++
 rust/bindgen_parameters                      |  17 +
 scripts/.gitignore                           |   1 +
 scripts/Kconfig.include                      |   6 +-
 scripts/Makefile                             |   3 +
 scripts/Makefile.build                       |  60 +++
 scripts/Makefile.debug                       |  10 +
 scripts/Makefile.host                        |  34 +-
 scripts/Makefile.lib                         |  12 +
 scripts/Makefile.modfinal                    |   8 +-
 scripts/cc-version.sh                        |  12 +-
 scripts/generate_rust_target.rs              | 227 +++++++++++
 scripts/is_rust_module.sh                    |  13 +
 scripts/kconfig/confdata.c                   |  75 ++++
 scripts/min-tool-version.sh                  |   6 +
 scripts/rust-is-available-bindgen-libclang.h |   2 +
 scripts/rust-is-available.sh                 | 158 ++++++++
 32 files changed, 1452 insertions(+), 23 deletions(-)
 create mode 100644 .rustfmt.toml
 create mode 100644 rust/.gitignore
 create mode 100644 rust/Makefile
 create mode 100644 rust/bindgen_parameters
 create mode 100644 scripts/generate_rust_target.rs
 create mode 100755 scripts/is_rust_module.sh
 create mode 100644 scripts/rust-is-available-bindgen-libclang.h
 create mode 100755 scripts/rust-is-available.sh

diff --git a/.gitignore b/.gitignore
index 7afd412dadd2..48c68948f476 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,6 +37,7 @@
 *.o
 *.o.*
 *.patch
+*.rmeta
 *.s
 *.so
 *.so.dbg
@@ -96,6 +97,7 @@ modules.order
 !.gitattributes
 !.gitignore
 !.mailmap
+!.rustfmt.toml
 
 #
 # Generated include files
@@ -161,3 +163,6 @@ x509.genkey
 
 # Documentation toolchain
 sphinx_*/
+
+# Rust analyzer configuration
+/rust-project.json
diff --git a/.rustfmt.toml b/.rustfmt.toml
new file mode 100644
index 000000000000..3de5cc497465
--- /dev/null
+++ b/.rustfmt.toml
@@ -0,0 +1,12 @@
+edition = "2021"
+newline_style = "Unix"
+
+# Unstable options that help catching some mistakes in formatting and that we may want to enable
+# when they become stable.
+#
+# They are kept here since they are useful to run from time to time.
+#format_code_in_doc_comments = true
+#reorder_impl_items = true
+#comment_width = 100
+#wrap_comments = true
+#normalize_comments = true
diff --git a/Makefile b/Makefile
index 7d5b0bfe7960..ce17ec71f89b 100644
--- a/Makefile
+++ b/Makefile
@@ -120,6 +120,15 @@ endif
 
 export KBUILD_CHECKSRC
 
+# Enable "clippy" (a linter) as part of the Rust compilation.
+#
+# Use 'make CLIPPY=1' to enable it.
+ifeq ("$(origin CLIPPY)", "command line")
+  KBUILD_CLIPPY := $(CLIPPY)
+endif
+
+export KBUILD_CLIPPY
+
 # Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
 # directory of external module to build. Setting M= takes precedence.
 ifeq ("$(origin M)", "command line")
@@ -267,7 +276,7 @@ no-dot-config-targets := $(clean-targets) \
 			 cscope gtags TAGS tags help% %docs check% coccicheck \
 			 $(version_h) headers headers_% archheaders archscripts \
 			 %asm-generic kernelversion %src-pkg dt_binding_check \
-			 outputmakefile
+			 outputmakefile rustavailable rustfmt rustfmtcheck
 # Installation targets should not require compiler. Unfortunately, vdso_install
 # is an exception where build artifacts may be updated. This must be fixed.
 no-compiler-targets := $(no-dot-config-targets) install dtbs_install \
@@ -436,6 +445,7 @@ else
 HOSTCC	= gcc
 HOSTCXX	= g++
 endif
+HOSTRUSTC = rustc
 
 KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
 			 -O2 -fomit-frame-pointer -std=gnu11 \
@@ -443,8 +453,26 @@ KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
 KBUILD_USERCFLAGS  := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
 KBUILD_USERLDFLAGS := $(USERLDFLAGS)
 
+# These flags apply to all Rust code in the tree, including the kernel and
+# host programs.
+export rust_common_flags := --edition=2021 \
+			    -Zbinary_dep_depinfo=y \
+			    -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \
+			    -Dunreachable_pub -Dnon_ascii_idents \
+			    -Wmissing_docs \
+			    -Drustdoc::missing_crate_level_docs \
+			    -Dclippy::correctness -Dclippy::style \
+			    -Dclippy::suspicious -Dclippy::complexity \
+			    -Dclippy::perf \
+			    -Dclippy::let_unit_value -Dclippy::mut_mut \
+			    -Dclippy::needless_bitwise_bool \
+			    -Dclippy::needless_continue \
+			    -Wclippy::dbg_macro
+
 KBUILD_HOSTCFLAGS   := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
 KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
+KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \
+			-Zallow-features= $(HOSTRUSTFLAGS)
 KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 
@@ -469,6 +497,12 @@ OBJDUMP		= $(CROSS_COMPILE)objdump
 READELF		= $(CROSS_COMPILE)readelf
 STRIP		= $(CROSS_COMPILE)strip
 endif
+RUSTC		= rustc
+RUSTDOC		= rustdoc
+RUSTFMT		= rustfmt
+CLIPPY_DRIVER	= clippy-driver
+BINDGEN		= bindgen
+CARGO		= cargo
 PAHOLE		= pahole
 RESOLVE_BTFIDS	= $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
 LEX		= flex
@@ -494,9 +528,11 @@ CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 		  -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
 NOSTDINC_FLAGS :=
 CFLAGS_MODULE   =
+RUSTFLAGS_MODULE =
 AFLAGS_MODULE   =
 LDFLAGS_MODULE  =
 CFLAGS_KERNEL	=
+RUSTFLAGS_KERNEL =
 AFLAGS_KERNEL	=
 LDFLAGS_vmlinux =
 
@@ -525,15 +561,42 @@ KBUILD_CFLAGS   := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
 		   -Werror=return-type -Wno-format-security \
 		   -std=gnu11
 KBUILD_CPPFLAGS := -D__KERNEL__
+KBUILD_RUSTFLAGS := $(rust_common_flags) \
+		    --target=$(objtree)/rust/target.json \
+		    -Cpanic=abort -Cembed-bitcode=n -Clto=n \
+		    -Cforce-unwind-tables=n -Ccodegen-units=1 \
+		    -Csymbol-mangling-version=v0 \
+		    -Crelocation-model=static \
+		    -Zfunction-sections=n \
+		    -Dclippy::float_arithmetic
+
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
+KBUILD_RUSTFLAGS_KERNEL :=
 KBUILD_AFLAGS_MODULE  := -DMODULE
 KBUILD_CFLAGS_MODULE  := -DMODULE
+KBUILD_RUSTFLAGS_MODULE := --cfg MODULE
 KBUILD_LDFLAGS_MODULE :=
 KBUILD_LDFLAGS :=
 CLANG_FLAGS :=
 
+ifeq ($(KBUILD_CLIPPY),1)
+	RUSTC_OR_CLIPPY_QUIET := CLIPPY
+	RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER)
+else
+	RUSTC_OR_CLIPPY_QUIET := RUSTC
+	RUSTC_OR_CLIPPY = $(RUSTC)
+endif
+
+ifdef RUST_LIB_SRC
+	export RUST_LIB_SRC
+endif
+
+export RUSTC_BOOTSTRAP := 1
+
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
+export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
+export HOSTRUSTC KBUILD_HOSTRUSTFLAGS
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
@@ -542,9 +605,10 @@ export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
+export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
-export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
-export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
+export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE
+export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL
 export PAHOLE_FLAGS
 
 # Files to ignore in find ... statements
@@ -725,7 +789,7 @@ $(KCONFIG_CONFIG):
 #
 # Do not use $(call cmd,...) here. That would suppress prompts from syncconfig,
 # so you cannot notice that Kconfig is waiting for the user input.
-%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG)
+%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG)
 	$(Q)$(kecho) "  SYNC    $@"
 	$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
 else # !may-sync-config
@@ -754,12 +818,28 @@ KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
 KBUILD_CFLAGS += -O2
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 2
 else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
 KBUILD_CFLAGS += -O3
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 3
 else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 KBUILD_CFLAGS += -Os
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := s
 endif
 
+# Always set `debug-assertions` and `overflow-checks` because their default
+# depends on `opt-level` and `debug-assertions`, respectively.
+KBUILD_RUSTFLAGS += -Cdebug-assertions=$(if $(CONFIG_RUST_DEBUG_ASSERTIONS),y,n)
+KBUILD_RUSTFLAGS += -Coverflow-checks=$(if $(CONFIG_RUST_OVERFLOW_CHECKS),y,n)
+KBUILD_RUSTFLAGS += -Copt-level=$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C),$(KBUILD_RUSTFLAGS_OPT_LEVEL_MAP))$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_0),0)$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_1),1)$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_2),2)$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_3),3)$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_S),s)$\
+	$(if $(CONFIG_RUST_OPT_LEVEL_Z),z)
+
 # Tell gcc to never replace conditional load with a non-conditional one
 ifdef CONFIG_CC_IS_GCC
 # gcc-10 renamed --param=allow-store-data-races=0 to
@@ -789,6 +869,9 @@ KBUILD_CFLAGS += $(stackp-flags-y)
 KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
 KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
 
+KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
+KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y)
+
 ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += -Qunused-arguments
 # The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
@@ -806,12 +889,15 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
 
 ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
+KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
 else
 # Some targets (ARM with Thumb2, for example), can't be built with frame
 # pointers.  For those, we don't have FUNCTION_TRACER automatically
 # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
 # incompatible with -fomit-frame-pointer with current GCC, so we don't use
 # -fomit-frame-pointer with FUNCTION_TRACER.
+# In the Rust target specification, "frame-pointer" is set explicitly
+# to "may-omit".
 ifndef CONFIG_FUNCTION_TRACER
 KBUILD_CFLAGS	+= -fomit-frame-pointer
 endif
@@ -876,8 +962,10 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH
 KBUILD_CFLAGS += -fno-inline-functions-called-once
 endif
 
+# `rustc`'s `-Zfunction-sections` applies to data too (as of 1.59.0).
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
 KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
+KBUILD_RUSTFLAGS_KERNEL += -Zfunction-sections=y
 LDFLAGS_vmlinux += --gc-sections
 endif
 
@@ -1019,10 +1107,11 @@ include $(addprefix $(srctree)/, $(include-y))
 # Do not add $(call cc-option,...) below this line. When you build the kernel
 # from the clean source tree, the GCC plugins do not exist at this point.
 
-# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
+# Add user supplied CPPFLAGS, AFLAGS, CFLAGS and RUSTFLAGS as the last assignments
 KBUILD_CPPFLAGS += $(KCPPFLAGS)
 KBUILD_AFLAGS   += $(KAFLAGS)
 KBUILD_CFLAGS   += $(KCFLAGS)
+KBUILD_RUSTFLAGS += $(KRUSTFLAGS)
 
 KBUILD_LDFLAGS_MODULE += --build-id=sha1
 LDFLAGS_vmlinux += --build-id=sha1
@@ -1091,6 +1180,7 @@ export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps
 ifeq ($(KBUILD_EXTMOD),)
 core-y			+= kernel/ certs/ mm/ fs/ ipc/ security/ crypto/
 core-$(CONFIG_BLOCK)	+= block/
+core-$(CONFIG_RUST)	+= rust/
 
 vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, \
 		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
@@ -1195,6 +1285,10 @@ prepare0: archprepare
 
 # All the preparing..
 prepare: prepare0
+ifdef CONFIG_RUST
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v
+	$(Q)$(MAKE) $(build)=rust
+endif
 
 PHONY += remove-stale-files
 remove-stale-files:
@@ -1483,7 +1577,7 @@ endif # CONFIG_MODULES
 # Directories & files removed with 'make clean'
 CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \
 	       modules.builtin modules.builtin.modinfo modules.nsdeps \
-	       compile_commands.json .thinlto-cache
+	       compile_commands.json .thinlto-cache rust/test rust/doc
 
 # Directories & files removed with 'make mrproper'
 MRPROPER_FILES += include/config include/generated          \
@@ -1494,7 +1588,8 @@ MRPROPER_FILES += include/config include/generated          \
 		  certs/signing_key.pem \
 		  certs/x509.genkey \
 		  vmlinux-gdb.py \
-		  *.spec
+		  *.spec \
+		  rust/target.json rust/libmacros.so
 
 # clean - Delete most, but leave enough to build external modules
 #
@@ -1519,6 +1614,9 @@ $(mrproper-dirs):
 
 mrproper: clean $(mrproper-dirs)
 	$(call cmd,rmfiles)
+	@find . $(RCS_FIND_IGNORE) \
+		\( -name '*.rmeta' \) \
+		-type f -print | xargs rm -f
 
 # distclean
 #
@@ -1606,6 +1704,23 @@ help:
 	@echo  '  kselftest-merge   - Merge all the config dependencies of'
 	@echo  '		      kselftest to existing .config.'
 	@echo  ''
+	@echo  'Rust targets:'
+	@echo  '  rustavailable   - Checks whether the Rust toolchain is'
+	@echo  '		    available and, if not, explains why.'
+	@echo  '  rustfmt	  - Reformat all the Rust code in the kernel'
+	@echo  '  rustfmtcheck	  - Checks if all the Rust code in the kernel'
+	@echo  '		    is formatted, printing a diff otherwise.'
+	@echo  '  rustdoc	  - Generate Rust documentation'
+	@echo  '		    (requires kernel .config)'
+	@echo  '  rusttest        - Runs the Rust tests'
+	@echo  '                    (requires kernel .config; downloads external repos)'
+	@echo  '  rust-analyzer	  - Generate rust-project.json rust-analyzer support file'
+	@echo  '		    (requires kernel .config)'
+	@echo  '  dir/file.[os]   - Build specified target only'
+	@echo  '  dir/file.i      - Build macro expanded source, similar to C preprocessing'
+	@echo  '                    (run with RUSTFMT=n to skip reformatting if needed)'
+	@echo  '  dir/file.ll     - Build the LLVM assembly file'
+	@echo  ''
 	@$(if $(dtstree), \
 		echo 'Devicetree:'; \
 		echo '* dtbs             - Build device tree blobs for enabled boards'; \
@@ -1677,6 +1792,52 @@ PHONY += $(DOC_TARGETS)
 $(DOC_TARGETS):
 	$(Q)$(MAKE) $(build)=Documentation $@
 
+
+# Rust targets
+# ---------------------------------------------------------------------------
+
+# "Is Rust available?" target
+PHONY += rustavailable
+rustavailable:
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v && echo >&2 "Rust is available!"
+
+# Documentation target
+#
+# Using the singular to avoid running afoul of `no-dot-config-targets`.
+PHONY += rustdoc
+rustdoc: prepare
+	$(Q)$(MAKE) $(build)=rust $@
+
+# Testing target
+PHONY += rusttest
+rusttest: prepare
+	$(Q)$(MAKE) $(build)=rust $@
+
+# Formatting targets
+PHONY += rustfmt rustfmtcheck
+
+# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream.
+#
+# We match using absolute paths since `find` does not resolve them
+# when matching, which is a problem when e.g. `srctree` is `..`.
+# We `grep` afterwards in order to remove the directory entry itself.
+rustfmt:
+	$(Q)find $(abs_srctree) -type f -name '*.rs' \
+		-o -path $(abs_srctree)/rust/alloc -prune \
+		-o -path $(abs_objtree)/rust/test -prune \
+		| grep -Fv $(abs_srctree)/rust/alloc \
+		| grep -Fv $(abs_objtree)/rust/test \
+		| grep -Fv generated \
+		| xargs $(RUSTFMT) $(rustfmt_flags)
+
+rustfmtcheck: rustfmt_flags = --check
+rustfmtcheck: rustfmt
+
+# IDE support targets
+PHONY += rust-analyzer
+rust-analyzer:
+	$(Q)$(MAKE) $(build)=rust $@
+
 # Misc
 # ---------------------------------------------------------------------------
 
diff --git a/arch/Kconfig b/arch/Kconfig
index 31c4fdc4a4ba..89d27b2a86dd 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -344,6 +344,12 @@ config HAVE_RSEQ
 	  This symbol should be selected by an architecture if it
 	  supports an implementation of restartable sequences.
 
+config HAVE_RUST
+	bool
+	help
+	  This symbol should be selected by an architecture if it
+	  supports Rust.
+
 config HAVE_FUNCTION_ARG_ACCESS_API
 	bool
 	help
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2e8091e2d8a8..1d0005080aeb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -116,6 +116,7 @@ config ARM
 	select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RSEQ
+	select HAVE_RUST if CPU_32v6 || CPU_32v6K
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UID16
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 20ea89d9ac2f..308cff85f5cb 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -198,6 +198,7 @@ config ARM64
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select MMU_GATHER_RCU_TABLE_FREE
 	select HAVE_RSEQ
+	select HAVE_RUST
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_KPROBES
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 174edabb74fa..ffbad38204b9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -239,6 +239,7 @@ config PPC
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_RUST			if PPC64 && CPU_LITTLE_ENDIAN
 	select HAVE_SETUP_PER_CPU_AREA		if PPC64
 	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 00fd9c548f26..63f7258984f3 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -101,6 +101,7 @@ config RISCV
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RUST if 64BIT
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 7d81102cffd4..663ae53b5597 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -26,6 +26,8 @@ ifeq ($(CONFIG_ARCH_RV64I),y)
 	KBUILD_CFLAGS += -mabi=lp64
 	KBUILD_AFLAGS += -mabi=lp64
 
+	KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv64
+
 	KBUILD_LDFLAGS += -melf64lriscv
 else
 	BITS := 32
@@ -33,6 +35,9 @@ else
 
 	KBUILD_CFLAGS += -mabi=ilp32
 	KBUILD_AFLAGS += -mabi=ilp32
+
+	KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv32
+
 	KBUILD_LDFLAGS += -melf32lriscv
 endif
 
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 4d398b80aea8..c9e76243c0b9 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -24,6 +24,7 @@ config UML
 	select TRACE_IRQFLAGS_SUPPORT
 	select TTY # Needed for line.c
 	select HAVE_ARCH_VMAP_STACK
+	select HAVE_RUST			if X86_64
 
 config MMU
 	bool
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4bed3abf444d..8d4e30f07a7d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -252,6 +252,7 @@ config X86
 	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
 	select HAVE_PREEMPT_DYNAMIC_CALL
 	select HAVE_RSEQ
+	select HAVE_RUST			if X86_64
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_USER_RETURN_NOTIFIER
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 63d50f65b828..5ac9b324751d 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -21,6 +21,8 @@ ifdef CONFIG_CC_IS_CLANG
 RETPOLINE_CFLAGS	:= -mretpoline-external-thunk
 RETPOLINE_VDSO_CFLAGS	:= -mretpoline
 endif
+RETPOLINE_RUSTFLAGS	:= -Ctarget-feature=+retpoline-external-thunk
+
 export RETPOLINE_CFLAGS
 export RETPOLINE_VDSO_CFLAGS
 
@@ -61,6 +63,8 @@ export BITS
 #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
 #
 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
+KBUILD_RUSTFLAGS += -Ctarget-feature=-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2
+KBUILD_RUSTFLAGS += -Ctarget-feature=-3dnow,-3dnowa,-avx,-avx2,+soft-float
 
 ifeq ($(CONFIG_X86_KERNEL_IBT),y)
 #
@@ -148,8 +152,17 @@ else
         cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
         KBUILD_CFLAGS += $(cflags-y)
 
+        rustflags-$(CONFIG_MK8)		+= -Ctarget-cpu=k8
+        rustflags-$(CONFIG_MPSC)	+= -Ctarget-cpu=nocona
+        rustflags-$(CONFIG_MCORE2)	+= -Ctarget-cpu=core2
+        rustflags-$(CONFIG_MATOM)	+= -Ctarget-cpu=atom
+        rustflags-$(CONFIG_GENERIC_CPU)	+= -Ztune-cpu=generic
+        KBUILD_RUSTFLAGS += $(rustflags-y)
+
         KBUILD_CFLAGS += -mno-red-zone
         KBUILD_CFLAGS += -mcmodel=kernel
+        KBUILD_RUSTFLAGS += -Cno-redzone=y
+        KBUILD_RUSTFLAGS += -Ccode-model=kernel
 endif
 
 #
@@ -185,6 +198,7 @@ ifdef CONFIG_RETPOLINE
   ifndef CONFIG_CC_IS_CLANG
     KBUILD_CFLAGS += -fno-jump-tables
   endif
+  KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS)
 endif
 
 ifdef CONFIG_SLS
diff --git a/init/Kconfig b/init/Kconfig
index ddcbefe535e9..3457cf596588 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -60,6 +60,17 @@ config LLD_VERSION
 	default $(ld-version) if LD_IS_LLD
 	default 0
 
+config RUST_IS_AVAILABLE
+	def_bool $(success,$(srctree)/scripts/rust-is-available.sh)
+	help
+	  This shows whether a suitable Rust toolchain is available (found).
+
+	  Please see Documentation/rust/quick-start.rst for instructions on how
+	  to satify the build requirements of Rust support.
+
+	  In particular, the Makefile target 'rustavailable' is useful to check
+	  why the Rust toolchain is not being detected.
+
 config CC_CAN_LINK
 	bool
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
@@ -146,7 +157,8 @@ config WERROR
 	default COMPILE_TEST
 	help
 	  A kernel build should not cause any compiler warnings, and this
-	  enables the '-Werror' flag to enforce that rule by default.
+	  enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
+	  to enforce that rule by default.
 
 	  However, if you have a new (or very old) compiler with odd and
 	  unusual warnings, or you have some architecture with problems,
@@ -2045,6 +2057,37 @@ config PROFILING
 	  Say Y here to enable the extended profiling support mechanisms used
 	  by profilers.
 
+config RUST
+	bool "Rust support"
+	depends on HAVE_RUST
+	depends on RUST_IS_AVAILABLE
+	depends on !MODVERSIONS
+	depends on !GCC_PLUGINS
+	depends on !DEBUG_INFO_BTF
+	select CONSTRUCTORS
+	help
+	  Enables Rust support in the kernel.
+
+	  This allows other Rust-related options, like drivers written in Rust,
+	  to be selected.
+
+	  It is also required to be able to load external kernel modules
+	  written in Rust.
+
+	  See Documentation/rust/ for more information.
+
+	  If unsure, say N.
+
+config RUSTC_VERSION_TEXT
+	string
+	depends on RUST
+	default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
+
+config BINDGEN_VERSION_TEXT
+	string
+	depends on RUST
+	default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
+
 #
 # Place an empty function call at each tracepoint site. Can be
 # dynamically changed for a probe function.
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 075cd25363ac..bfc28f52b603 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2760,6 +2760,161 @@ config HYPERV_TESTING
 
 endmenu # "Kernel Testing and Coverage"
 
+menu "Rust hacking"
+
+config RUST_DEBUG_ASSERTIONS
+	bool "Debug assertions"
+	depends on RUST
+	help
+	  Enables rustc's `-Cdebug-assertions` codegen option.
+
+	  This flag lets you turn `cfg(debug_assertions)` conditional
+	  compilation on or off. This can be used to enable extra debugging
+	  code in development but not in production. For example, it controls
+	  the behavior of the standard library's `debug_assert!` macro.
+
+	  Note that this will apply to all Rust code, including `core`.
+
+	  If unsure, say N.
+
+config RUST_OVERFLOW_CHECKS
+	bool "Overflow checks"
+	default y
+	depends on RUST
+	help
+	  Enables rustc's `-Coverflow-checks` codegen option.
+
+	  This flag allows you to control the behavior of runtime integer
+	  overflow. When overflow-checks are enabled, a Rust panic will occur
+	  on overflow.
+
+	  Note that this will apply to all Rust code, including `core`.
+
+	  If unsure, say Y.
+
+choice
+	prompt "Optimization level"
+	default RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C
+	depends on RUST
+	help
+	  Controls rustc's `-Copt-level` codegen option.
+
+	  This flag controls the optimization level.
+
+	  If unsure, say "Similar as chosen for C".
+
+config RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C
+	bool "Similar as chosen for C"
+	help
+	  This choice will pick a similar optimization level as chosen in
+	  the "Compiler optimization level" for C:
+
+	      -O2 is currently mapped to -Copt-level=2
+	      -O3 is currently mapped to -Copt-level=3
+	      -Os is currently mapped to -Copt-level=s
+
+	  The mapping may change over time to follow the intended semantics
+	  of the choice for C as sensibly as possible.
+
+	  This is the default.
+
+config RUST_OPT_LEVEL_0
+	bool "No optimizations (-Copt-level=0)"
+	help
+	  Not recommended for most purposes. It may come in handy for debugging
+	  suspected optimizer bugs, unexpected undefined behavior, etc.
+
+	  Note that this level will *not* enable debug assertions nor overflow
+	  checks on its own (like it happens when interacting with rustc
+	  directly). Use the corresponding configuration options to control
+	  that instead, orthogonally.
+
+	  Note this level may cause excessive stack usage, which can lead to stack
+	  overflow and subsequent crashes.
+
+config RUST_OPT_LEVEL_1
+	bool "Basic optimizations (-Copt-level=1)"
+	help
+	  Useful for debugging without getting too lost, but without
+	  the overhead and boilerplate of no optimizations at all.
+
+	  Note this level may cause excessive stack usage, which can lead to stack
+	  overflow and subsequent crashes.
+
+config RUST_OPT_LEVEL_2
+	bool "Some optimizations (-Copt-level=2)"
+	help
+	  The sensible choice in most cases.
+
+config RUST_OPT_LEVEL_3
+	bool "All optimizations (-Copt-level=3)"
+	help
+	  Yet more performance (hopefully).
+
+config RUST_OPT_LEVEL_S
+	bool "Optimize for size (-Copt-level=s)"
+	help
+	  Smaller kernel, ideally without too much performance loss.
+
+config RUST_OPT_LEVEL_Z
+	bool "Optimize for size, no loop vectorization (-Copt-level=z)"
+	help
+	  Like the previous level, but also turn off loop vectorization.
+
+endchoice
+
+choice
+	prompt "Build-time assertions"
+	default RUST_BUILD_ASSERT_ALLOW if RUST_OPT_LEVEL_0
+	default RUST_BUILD_ASSERT_DENY if !RUST_OPT_LEVEL_0
+	depends on RUST
+	help
+	  Controls how are `build_error!` and `build_assert!` handled during build.
+
+	  If calls to them exist in the binary, it may indicate a violated invariant
+	  or that the optimizer failed to verify the invariant during compilation.
+	  You can choose to abort compilation or ignore them during build and let the
+	  check be carried to runtime.
+
+	  If optimizations are turned off, you cannot select "Deny".
+
+	  If unsure, say "Deny".
+
+config RUST_BUILD_ASSERT_ALLOW
+	bool "Allow"
+	help
+	  Unoptimized calls to `build_error!` will be converted to `panic!`
+	  and checked at runtime.
+
+config RUST_BUILD_ASSERT_WARN
+	bool "Warn"
+	help
+	  Unoptimized calls to `build_error!` will be converted to `panic!`
+	  and checked at runtime, but warnings will be generated when building.
+
+config RUST_BUILD_ASSERT_DENY
+	bool "Deny"
+	depends on !RUST_OPT_LEVEL_0
+	help
+	  Unoptimized calls to `build_error!` will abort compilation.
+
+endchoice
+
+config RUST_KERNEL_KUNIT_TEST
+	bool "KUnit test for the `kernel` crate" if !KUNIT_ALL_TESTS
+	depends on RUST && KUNIT=y
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the documentation tests of the `kernel` crate
+	  as KUnit tests.
+
+	  For more information on KUnit and unit tests in general,
+	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
+
+endmenu # "Rust"
+
 source "Documentation/Kconfig"
 
 endmenu # Kernel hacking
diff --git a/rust/.gitignore b/rust/.gitignore
new file mode 100644
index 000000000000..89b602d91109
--- /dev/null
+++ b/rust/.gitignore
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+target.json
+bindings_generated.rs
+bindings_helpers_generated.rs
+exports_*_generated.h
+doctests_kernel_generated.rs
+doctests_kernel_generated_kunit.c
+doc/
+test/
diff --git a/rust/Makefile b/rust/Makefile
new file mode 100644
index 000000000000..a7dc37027fe2
--- /dev/null
+++ b/rust/Makefile
@@ -0,0 +1,398 @@
+# SPDX-License-Identifier: GPL-2.0
+
+always-$(CONFIG_RUST) += target.json
+no-clean-files += target.json
+
+obj-$(CONFIG_RUST) += core.o compiler_builtins.o
+always-$(CONFIG_RUST) += exports_core_generated.h
+
+# Missing prototypes are expected in the helpers since these are exported
+# for Rust only, thus there is no header nor prototypes.
+obj-$(CONFIG_RUST) += helpers.o
+CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations
+
+always-$(CONFIG_RUST) += libmacros.so
+no-clean-files += libmacros.so
+
+always-$(CONFIG_RUST) += bindings_generated.rs bindings_helpers_generated.rs
+obj-$(CONFIG_RUST) += alloc.o kernel.o
+always-$(CONFIG_RUST) += exports_alloc_generated.h exports_kernel_generated.h
+
+ifdef CONFIG_RUST_BUILD_ASSERT_DENY
+always-$(CONFIG_RUST) += build_error.o
+else
+obj-$(CONFIG_RUST) += build_error.o
+endif
+
+obj-$(CONFIG_RUST) += exports.o
+
+obj-$(CONFIG_RUST_KERNEL_KUNIT_TEST) += doctests_kernel_generated.o
+obj-$(CONFIG_RUST_KERNEL_KUNIT_TEST) += doctests_kernel_generated_kunit.o
+
+# Avoids running `$(RUSTC)` for the sysroot when it may not be available.
+ifdef CONFIG_RUST
+
+# `$(rust_flags)` is passed in case the user added `--sysroot`.
+rustc_sysroot := $(shell $(RUSTC) $(rust_flags) --print sysroot)
+rustc_host_target := $(shell $(RUSTC) --version --verbose | grep -F 'host: ' | cut -d' ' -f2)
+RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library
+
+ifeq ($(quiet),silent_)
+cargo_quiet=-q
+rust_test_quiet=-q
+rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
+else ifeq ($(quiet),quiet_)
+rust_test_quiet=-q
+rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
+else
+cargo_quiet=--verbose
+endif
+
+core-cfgs = \
+    --cfg no_fp_fmt_parse
+
+alloc-cfgs = \
+    --cfg no_global_oom_handling \
+    --cfg no_rc \
+    --cfg no_sync
+
+quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
+      cmd_rustdoc = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTDOC) $(if $(rustdoc_host),$(rust_common_flags),$(rust_flags)) \
+		$(rustc_target_flags) -L$(objtree)/$(obj) \
+		--output $(objtree)/$(obj)/doc \
+		--crate-name $(subst rustdoc-,,$@) \
+		@$(objtree)/include/generated/rustc_cfg $<
+
+# The `html_logo_url` and `html_favicon_url` forms of the `doc` attribute
+# can be used to specify a custom logo. However:
+#   - The given value is used as-is, thus it cannot be relative or a local file
+#     (unlike the non-custom case) since the generated docs have subfolders.
+#   - It requires adding it to every crate.
+#   - It requires changing `core` which comes from the sysroot.
+#
+# Using `-Zcrate-attr` would solve the last two points, but not the first.
+# The https://github.com/rust-lang/rfcs/pull/3226 RFC suggests two new
+# command-like flags to solve the issue. Meanwhile, we use the non-custom case
+# and then retouch the generated files.
+rustdoc: rustdoc-core rustdoc-macros rustdoc-compiler_builtins \
+    rustdoc-alloc rustdoc-kernel
+	$(Q)cp $(srctree)/Documentation/logo.gif $(objtree)/$(obj)/doc
+	$(Q)find $(objtree)/$(obj)/doc -name '*.html' -type f -print0 | xargs -0 sed -Ei \
+		-e 's:rust-logo\.svg:logo.gif:g' \
+		-e 's:rust-logo\.png:logo.gif:g' \
+		-e 's:favicon\.svg:logo.gif:g' \
+		-e 's:<link rel="alternate icon" type="image/png" href="[./]*favicon-(16x16|32x32)\.png">::g'
+
+rustdoc-macros: private rustdoc_host = yes
+rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \
+    --extern proc_macro
+rustdoc-macros: $(src)/macros/lib.rs FORCE
+	$(call if_changed,rustdoc)
+
+rustdoc-core: private rustc_target_flags = $(core-cfgs)
+rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE
+	$(call if_changed,rustdoc)
+
+rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE
+	$(call if_changed,rustdoc)
+
+# We need to allow `rustdoc::broken_intra_doc_links` because some
+# `no_global_oom_handling` functions refer to non-`no_global_oom_handling`
+# functions. Ideally `rustdoc` would have a way to distinguish broken links
+# due to things that are "configured out" vs. entirely non-existing ones.
+rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \
+    -Arustdoc::broken_intra_doc_links
+rustdoc-alloc: $(src)/alloc/lib.rs rustdoc-core rustdoc-compiler_builtins FORCE
+	$(call if_changed,rustdoc)
+
+rustdoc-kernel: private rustc_target_flags = --extern alloc \
+    --extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so
+rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \
+    rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \
+    $(obj)/bindings_generated.rs $(obj)/bindings_helpers_generated.rs FORCE
+	$(call if_changed,rustdoc)
+
+quiet_cmd_rustc_test_library = RUSTC TL $<
+      cmd_rustc_test_library = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTC) $(rust_common_flags) \
+		@$(objtree)/include/generated/rustc_cfg $(rustc_target_flags) \
+		--crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \
+		--out-dir $(objtree)/$(obj)/test --cfg testlib \
+		--sysroot $(objtree)/$(obj)/test/sysroot \
+		-L$(objtree)/$(obj)/test \
+		--crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $<
+
+rusttestlib-build_error: $(src)/build_error.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test_library)
+
+rusttestlib-macros: private rustc_target_flags = --extern proc_macro
+rusttestlib-macros: private rustc_test_library_proc = yes
+rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test_library)
+
+quiet_cmd_rustdoc_test = RUSTDOC T $<
+      cmd_rustdoc_test = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTDOC) --test $(rust_common_flags) \
+		@$(objtree)/include/generated/rustc_cfg \
+		$(rustc_target_flags) $(rustdoc_test_target_flags) \
+		--sysroot $(objtree)/$(obj)/test/sysroot $(rustdoc_test_quiet) \
+		-L$(objtree)/$(obj)/test --output $(objtree)/$(obj)/doc \
+		--crate-name $(subst rusttest-,,$@) $<
+
+quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $<
+      cmd_rustdoc_test_kernel = \
+	rm -rf $(objtree)/$(obj)/test/doctests/kernel; \
+	mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTDOC) --test $(rust_flags) \
+		@$(objtree)/include/generated/rustc_cfg \
+		-L$(objtree)/$(obj) --extern alloc --extern kernel \
+		--extern build_error --extern macros \
+		--no-run --crate-name kernel -Zunstable-options \
+		--test-builder $(srctree)/scripts/rustdoc_test_builder.py \
+		$< $(rustdoc_test_kernel_quiet); \
+	$(srctree)/scripts/rustdoc_test_gen.py
+
+%/doctests_kernel_generated.rs %/doctests_kernel_generated_kunit.c: $(src)/kernel/lib.rs $(obj)/kernel.o FORCE
+	$(call if_changed,rustdoc_test_kernel)
+
+# We cannot use `-Zpanic-abort-tests` because some tests are dynamic,
+# so for the moment we skip `-Cpanic=abort`.
+quiet_cmd_rustc_test = RUSTC T  $<
+      cmd_rustc_test = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTC) --test $(rust_common_flags) \
+		@$(objtree)/include/generated/rustc_cfg \
+		$(rustc_target_flags) --out-dir $(objtree)/$(obj)/test \
+		--sysroot $(objtree)/$(obj)/test/sysroot \
+		-L$(objtree)/$(obj)/test \
+		--crate-name $(subst rusttest-,,$@) $<; \
+	$(objtree)/$(obj)/test/$(subst rusttest-,,$@) $(rust_test_quiet) \
+		$(rustc_test_run_flags)
+
+rusttest: rusttest-macros rusttest-kernel
+
+# This prepares a custom sysroot with our custom `alloc` instead of
+# the standard one.
+#
+# This requires several hacks:
+#   - Unlike `core` and `alloc`, `std` depends on more than a dozen crates,
+#     including third-party crates that need to be downloaded, plus custom
+#     `build.rs` steps. Thus hardcoding things here is not maintainable.
+#   - `cargo` knows how to build the standard library, but it is an unstable
+#     feature so far (`-Zbuild-std`).
+#   - `cargo` only considers the use case of building the standard library
+#     to use it in a given package. Thus we need to create a dummy package
+#     and pick the generated libraries from there.
+#   - Since we only keep a subset of upstream `alloc` in-tree, we need
+#     to recreate it on the fly by putting our sources on top.
+#   - The usual ways of modifying the dependency graph in `cargo` do not seem
+#     to apply for the `-Zbuild-std` steps, thus we have to mislead it
+#     by modifying the sources in the sysroot.
+#   - To avoid messing with the user's Rust installation, we create a clone
+#     of the sysroot. However, `cargo` ignores `RUSTFLAGS` in the `-Zbuild-std`
+#     steps, thus we use a wrapper binary passed via `RUSTC` to pass the flag.
+#
+# In the future, we hope to avoid the whole ordeal by either:
+#   - Making the `test` crate not depend on `std` (either improving upstream
+#     or having our own custom crate).
+#   - Making the tests run in kernel space (requires the previous point).
+#   - Making `std` and friends be more like a "normal" crate, so that
+#     `-Zbuild-std` and related hacks are not needed.
+quiet_cmd_rustsysroot = RUSTSYSROOT
+      cmd_rustsysroot = \
+	rm -rf $(objtree)/$(obj)/test; \
+	mkdir -p $(objtree)/$(obj)/test; \
+	cp -a $(rustc_sysroot) $(objtree)/$(obj)/test/sysroot; \
+	cp -r $(srctree)/$(src)/alloc/* \
+		$(objtree)/$(obj)/test/sysroot/lib/rustlib/src/rust/library/alloc/src; \
+	echo '\#!/bin/sh' > $(objtree)/$(obj)/test/rustc_sysroot; \
+	echo "$(RUSTC) --sysroot=$(abspath $(objtree)/$(obj)/test/sysroot) \"\$$@\"" \
+		>> $(objtree)/$(obj)/test/rustc_sysroot; \
+	chmod u+x $(objtree)/$(obj)/test/rustc_sysroot; \
+	$(CARGO) -q new $(objtree)/$(obj)/test/dummy; \
+	RUSTC=$(objtree)/$(obj)/test/rustc_sysroot $(CARGO) $(cargo_quiet) \
+		test -Zbuild-std --target $(rustc_host_target) \
+		--manifest-path $(objtree)/$(obj)/test/dummy/Cargo.toml; \
+	rm $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib/*; \
+	cp $(objtree)/$(obj)/test/dummy/target/$(rustc_host_target)/debug/deps/* \
+		$(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib
+
+rusttest-prepare: FORCE
+	$(call if_changed,rustsysroot)
+
+rusttest-macros: private rustc_target_flags = --extern proc_macro
+rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro
+rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test)
+	$(call if_changed,rustdoc_test)
+
+rusttest-kernel: private rustc_target_flags = --extern alloc \
+    --extern build_error --extern macros
+rusttest-kernel: private rustc_test_run_flags = --skip bindgen_test_layout_
+rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \
+    rusttestlib-build_error rusttestlib-macros FORCE
+	$(call if_changed,rustc_test)
+	$(call if_changed,rustc_test_library)
+
+filechk_rust_target = $(objtree)/scripts/generate_rust_target < $<
+
+$(obj)/target.json: $(objtree)/include/config/auto.conf FORCE
+	$(call filechk,rust_target)
+
+ifdef CONFIG_CC_IS_CLANG
+bindgen_c_flags = $(c_flags)
+else
+# bindgen relies on libclang to parse C. Ideally, bindgen would support a GCC
+# plugin backend and/or the Clang driver would be perfectly compatible with GCC.
+#
+# For the moment, here we are tweaking the flags on the fly. This is a hack,
+# and some kernel configurations may not work (e.g. `GCC_PLUGIN_RANDSTRUCT`
+# if we end up using one of those structs).
+bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
+	-mskip-rax-setup -mgeneral-regs-only -msign-return-address=% \
+	-mindirect-branch=thunk-extern -mindirect-branch-register \
+	-mrecord-mcount -mabi=lp64 -mstack-protector-guard% -mtraceback=no \
+	-mno-pointers-to-nested-functions -mno-string -mno-strict-align \
+	-mstrict-align \
+	-fconserve-stack -falign-jumps=% -falign-loops=% \
+	-femit-struct-debug-baseonly -fno-ipa-cp-clone -fno-ipa-sra \
+	-fno-partial-inlining -fplugin-arg-arm_ssp_per_task_plugin-% \
+	-fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \
+	-fzero-call-used-regs=% -fno-stack-clash-protection \
+	-fno-inline-functions-called-once \
+	--param=% --param asan-%
+
+# Derived from `scripts/Makefile.clang`.
+BINDGEN_TARGET_arm	:= arm-linux-gnueabi
+BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
+BINDGEN_TARGET_powerpc	:= powerpc64le-linux-gnu
+BINDGEN_TARGET_riscv	:= riscv64-linux-gnu
+BINDGEN_TARGET_x86	:= x86_64-linux-gnu
+BINDGEN_TARGET		:= $(BINDGEN_TARGET_$(SRCARCH))
+
+# All warnings are inhibited since GCC builds are very experimental,
+# many GCC warnings are not supported by Clang, they may only appear in
+# some configurations, with new GCC versions, etc.
+bindgen_extra_c_flags = -w --target=$(BINDGEN_TARGET)
+
+bindgen_c_flags = $(filter-out $(bindgen_skip_c_flags), $(c_flags)) \
+	$(bindgen_extra_c_flags)
+endif
+
+ifdef CONFIG_LTO
+bindgen_c_flags_lto = $(filter-out $(CC_FLAGS_LTO), $(bindgen_c_flags))
+else
+bindgen_c_flags_lto = $(bindgen_c_flags)
+endif
+
+bindgen_c_flags_final = $(bindgen_c_flags_lto)
+
+quiet_cmd_bindgen = BINDGEN $@
+      cmd_bindgen = \
+	$(BINDGEN) $< $(bindgen_target_flags) \
+		--use-core --with-derive-default --ctypes-prefix c_types \
+		--no-debug '.*' \
+		--size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE \
+		$(bindgen_target_cflags) $(bindgen_target_extra)
+
+$(obj)/bindings_generated.rs: private bindgen_target_flags = \
+    $(shell grep -v '^\#\|^$$' $(srctree)/$(src)/bindgen_parameters)
+$(obj)/bindings_generated.rs: $(src)/kernel/bindings_helper.h \
+    $(src)/bindgen_parameters FORCE
+	$(call if_changed_dep,bindgen)
+
+# See `CFLAGS_REMOVE_helpers.o` above. In addition, Clang on C does not warn
+# with `-Wmissing-declarations` (unlike GCC), so it is not strictly needed here
+# given it is `libclang`; but for consistency, future Clang changes and/or
+# a potential future GCC backend for `bindgen`, we disable it too.
+$(obj)/bindings_helpers_generated.rs: private bindgen_target_flags = \
+    --blacklist-type '.*' --whitelist-var '' \
+    --whitelist-function 'rust_helper_.*'
+$(obj)/bindings_helpers_generated.rs: private bindgen_target_cflags = \
+    -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
+$(obj)/bindings_helpers_generated.rs: private bindgen_target_extra = ; \
+    sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/#[link_name="rust_helper_\1"]\n    pub fn \1/g' $@
+$(obj)/bindings_helpers_generated.rs: $(src)/helpers.c FORCE
+	$(call if_changed_dep,bindgen)
+
+quiet_cmd_exports = EXPORTS $@
+      cmd_exports = \
+	$(NM) -p --defined-only $< \
+		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
+		| xargs -Isymbol \
+		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
+
+$(obj)/exports_core_generated.h: $(obj)/core.o FORCE
+	$(call if_changed,exports)
+
+$(obj)/exports_alloc_generated.h: $(obj)/alloc.o FORCE
+	$(call if_changed,exports)
+
+$(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
+	$(call if_changed,exports)
+
+quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
+      cmd_rustc_procmacro = \
+	$(RUSTC_OR_CLIPPY) $(rust_common_flags) \
+		--emit=dep-info,link --extern proc_macro \
+		--crate-type proc-macro --out-dir $(objtree)/$(obj) \
+		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
+	mv $(objtree)/$(obj)/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+
+# Procedural macros can only be used with the `rustc` that compiled it.
+# Therefore, to get `libmacros.so` automatically recompiled when the compiler
+# version changes, we add `core.o` as a dependency (even if it is not needed).
+$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE
+	$(call if_changed_dep,rustc_procmacro)
+
+quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@
+      cmd_rustc_library = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \
+		$(filter-out $(skip_flags),$(rust_flags) $(rustc_target_flags)) \
+		--emit=dep-info,obj,metadata --crate-type rlib \
+		--out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \
+		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
+	mv $(objtree)/$(obj)/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile) \
+	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
+
+rust-analyzer:
+	$(Q)$(srctree)/scripts/generate_rust_analyzer.py $(srctree) $(objtree) \
+		$(RUST_LIB_SRC) > $(objtree)/rust-project.json
+
+$(obj)/core.o: private skip_clippy = 1
+$(obj)/core.o: private skip_flags = -Dunreachable_pub
+$(obj)/core.o: private rustc_target_flags = $(core-cfgs)
+$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs $(obj)/target.json FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'
+$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/alloc.o: private skip_clippy = 1
+$(obj)/alloc.o: private skip_flags = -Dunreachable_pub
+$(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs)
+$(obj)/alloc.o: $(src)/alloc/lib.rs $(obj)/compiler_builtins.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/kernel.o: private rustc_target_flags = --extern alloc \
+    --extern build_error --extern macros
+$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \
+    $(obj)/libmacros.so $(obj)/bindings_generated.rs \
+    $(obj)/bindings_helpers_generated.rs FORCE
+	$(call if_changed_dep,rustc_library)
+
+endif # CONFIG_RUST
diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
new file mode 100644
index 000000000000..6c77865e8345
--- /dev/null
+++ b/rust/bindgen_parameters
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+
+--opaque-type xregs_state
+--opaque-type desc_struct
+--opaque-type arch_lbr_state
+--opaque-type local_apic
+
+# `try` is a reserved keyword since Rust 2018; solved in `bindgen` v0.59.2,
+# commit 2aed6b021680 ("context: Escape the try keyword properly").
+--opaque-type kunit_try_catch
+
+# If SMP is disabled, `arch_spinlock_t` is defined as a ZST which triggers a Rust
+# warning. We don't need to peek into it anyway.
+--opaque-type spinlock
+
+# `seccomp`'s comment gets understood as a doctest
+--no-doc-comments
diff --git a/scripts/.gitignore b/scripts/.gitignore
index eed308bef604..b7aec8eb1bd4 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 /asn1_compiler
 /bin2c
+/generate_rust_target
 /insert-sys-cert
 /kallsyms
 /module.lds
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index 0496efd6e117..83e850321eb6 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -36,12 +36,12 @@ ld-option = $(success,$(LD) -v $(1))
 as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -)
 
 # check if $(CC) and $(LD) exist
-$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
+$(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found)
 $(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
 
-# Get the compiler name, version, and error out if it is not supported.
+# Get the C compiler name, version, and error out if it is not supported.
 cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC))
-$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not supported.)
+$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this C compiler is not supported.)
 cc-name := $(shell,set -- $(cc-info) && echo $1)
 cc-version := $(shell,set -- $(cc-info) && echo $2)
 
diff --git a/scripts/Makefile b/scripts/Makefile
index ce5aa9030b74..a278345e7820 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -10,6 +10,9 @@ hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT)		+= sorttable
 hostprogs-always-$(CONFIG_ASN1)				+= asn1_compiler
 hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT)		+= sign-file
 hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE)	+= insert-sys-cert
+hostprogs-always-$(CONFIG_RUST)				+= generate_rust_target
+
+generate_rust_target-rust := y
 
 HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
 HOSTLDLIBS_sorttable = -lpthread
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 33c1ed581522..533631753b16 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -26,6 +26,7 @@ EXTRA_CPPFLAGS :=
 EXTRA_LDFLAGS  :=
 asflags-y  :=
 ccflags-y  :=
+rustflags-y :=
 cppflags-y :=
 ldflags-y  :=
 
@@ -324,6 +325,65 @@ quiet_cmd_cc_lst_c = MKLST   $@
 $(obj)/%.lst: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_lst_c)
 
+# Compile Rust sources (.rs)
+# ---------------------------------------------------------------------------
+
+rust_allowed_features := allocator_api,bench_black_box,concat_idents,generic_associated_types
+
+rust_common_cmd = \
+	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
+	-Zallow-features=$(rust_allowed_features) \
+	-Zcrate-attr=no_std \
+	-Zcrate-attr='feature($(rust_allowed_features))' \
+	--extern alloc --extern kernel \
+	--crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
+	--crate-name $(basename $(notdir $@))
+
+rust_handle_depfile = \
+	mv $(obj)/$(basename $(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+
+# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
+# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
+# the compiler shows a warning if it is not 1. However, if we ever stop
+# requesting it explicitly and we start using some other `--emit` that does not
+# imply it (and for which codegen is performed), then we would be out of sync,
+# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
+# would not match each other.
+
+quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_o_rs = \
+	$(rust_common_cmd) --emit=dep-info,obj $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.o: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_o_rs)
+
+quiet_cmd_rustc_i_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_i_rs = \
+	$(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
+	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
+	$(rust_handle_depfile)
+
+$(obj)/%.i: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_i_rs)
+
+quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_s_rs = \
+	$(rust_common_cmd) --emit=dep-info,asm $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.s: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_s_rs)
+
+quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_ll_rs = \
+	$(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.ll: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_ll_rs)
+
 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------
 
diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
index 9f39b0130551..fe87389d52c0 100644
--- a/scripts/Makefile.debug
+++ b/scripts/Makefile.debug
@@ -1,4 +1,5 @@
 DEBUG_CFLAGS	:=
+DEBUG_RUSTFLAGS	:=
 
 ifdef CONFIG_DEBUG_INFO_SPLIT
 DEBUG_CFLAGS	+= -gsplit-dwarf
@@ -10,6 +11,12 @@ ifndef CONFIG_AS_IS_LLVM
 KBUILD_AFLAGS	+= -Wa,-gdwarf-2
 endif
 
+ifdef CONFIG_DEBUG_INFO_REDUCED
+DEBUG_RUSTFLAGS += -Cdebuginfo=1
+else
+DEBUG_RUSTFLAGS += -Cdebuginfo=2
+endif
+
 ifndef CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
 dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4
 dwarf-version-$(CONFIG_DEBUG_INFO_DWARF5) := 5
@@ -31,3 +38,6 @@ endif
 
 KBUILD_CFLAGS += $(DEBUG_CFLAGS)
 export DEBUG_CFLAGS
+
+KBUILD_RUSTFLAGS += $(DEBUG_RUSTFLAGS)
+export DEBUG_RUSTFLAGS
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 278b4d6ac945..da133780b751 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -22,6 +22,8 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
 # to preprocess a data file.
 #
 # Both C and C++ are supported, but preferred language is C for such utilities.
+# Rust is also supported, but it may only be used in scenarios where a Rust
+# toolchain is required to be available (e.g. when  `CONFIG_RUST` is enabled).
 #
 # Sample syntax (see Documentation/kbuild/makefiles.rst for reference)
 # hostprogs := bin2hex
@@ -37,15 +39,20 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
 # qconf-objs      := menu.o
 # Will compile qconf as a C++ program, and menu as a C program.
 # They are linked as C++ code to the executable qconf
+#
+# hostprogs   := target
+# target-rust := y
+# Will compile `target` as a Rust program, using `target.rs` as the crate root.
+# The crate may consist of several source files.
 
 # C code
 # Executables compiled from a single .c file
 host-csingle	:= $(foreach m,$(hostprogs), \
-			$(if $($(m)-objs)$($(m)-cxxobjs),,$(m)))
+			$(if $($(m)-objs)$($(m)-cxxobjs)$($(m)-rust),,$(m)))
 
 # C executables linked based on several .o files
 host-cmulti	:= $(foreach m,$(hostprogs),\
-		   $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m))))
+		   $(if $($(m)-cxxobjs)$($(m)-rust),,$(if $($(m)-objs),$(m))))
 
 # Object (.o) files compiled from .c files
 host-cobjs	:= $(sort $(foreach m,$(hostprogs),$($(m)-objs)))
@@ -58,11 +65,17 @@ host-cxxmulti	:= $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m)))
 # C++ Object (.o) files compiled from .cc files
 host-cxxobjs	:= $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
 
+# Rust code
+# Executables compiled from a single Rust crate (which may consist of
+# one or more .rs files)
+host-rust	:= $(foreach m,$(hostprogs),$(if $($(m)-rust),$(m)))
+
 host-csingle	:= $(addprefix $(obj)/,$(host-csingle))
 host-cmulti	:= $(addprefix $(obj)/,$(host-cmulti))
 host-cobjs	:= $(addprefix $(obj)/,$(host-cobjs))
 host-cxxmulti	:= $(addprefix $(obj)/,$(host-cxxmulti))
 host-cxxobjs	:= $(addprefix $(obj)/,$(host-cxxobjs))
+host-rust	:= $(addprefix $(obj)/,$(host-rust))
 
 #####
 # Handle options to gcc. Support building with separate output directory
@@ -71,6 +84,8 @@ _hostc_flags   = $(KBUILD_HOSTCFLAGS)   $(HOST_EXTRACFLAGS)   \
                  $(HOSTCFLAGS_$(target-stem).o)
 _hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
                  $(HOSTCXXFLAGS_$(target-stem).o)
+_hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
+                  $(HOSTRUSTFLAGS_$(target-stem))
 
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
@@ -82,6 +97,7 @@ endif
 
 hostc_flags    = -Wp,-MMD,$(depfile) $(_hostc_flags)
 hostcxx_flags  = -Wp,-MMD,$(depfile) $(_hostcxx_flags)
+hostrust_flags = $(_hostrust_flags)
 
 #####
 # Compile programs on the host
@@ -128,5 +144,17 @@ quiet_cmd_host-cxxobjs	= HOSTCXX $@
 $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
 	$(call if_changed_dep,host-cxxobjs)
 
+# Create executable from a single Rust crate (which may consist of
+# one or more `.rs` files)
+# host-rust -> Executable
+quiet_cmd_host-rust	= HOSTRUSTC $@
+      cmd_host-rust	= \
+	$(HOSTRUSTC) $(hostrust_flags) --emit=dep-info,link \
+		--out-dir=$(obj)/ $<; \
+	mv $(obj)/$(target-stem).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+$(host-rust): $(obj)/%: $(src)/%.rs FORCE
+	$(call if_changed_dep,host-rust)
+
 targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \
-	   $(host-cxxmulti) $(host-cxxobjs)
+	   $(host-cxxmulti) $(host-cxxobjs) $(host-rust)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 9f69ecdd7977..f3e623f242df 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -8,6 +8,7 @@ ldflags-y  += $(EXTRA_LDFLAGS)
 # flags that take effect in current and sub directories
 KBUILD_AFLAGS += $(subdir-asflags-y)
 KBUILD_CFLAGS += $(subdir-ccflags-y)
+KBUILD_RUSTFLAGS += $(subdir-rustflags-y)
 
 # Figure out what we need to build from the various variables
 # ===========================================================================
@@ -128,6 +129,10 @@ _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
                      $(filter-out $(ccflags-remove-y), \
                          $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(ccflags-y)) \
                      $(CFLAGS_$(target-stem).o))
+_rust_flags    = $(filter-out $(RUSTFLAGS_REMOVE_$(target-stem).o), \
+                     $(filter-out $(rustflags-remove-y), \
+                         $(KBUILD_RUSTFLAGS) $(rustflags-y)) \
+                     $(RUSTFLAGS_$(target-stem).o))
 _a_flags       = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \
                      $(filter-out $(asflags-remove-y), \
                          $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(asflags-y)) \
@@ -202,6 +207,11 @@ modkern_cflags =                                          \
 		$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 		$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL) $(modfile_flags))
 
+modkern_rustflags =                                              \
+	$(if $(part-of-module),                                   \
+		$(KBUILD_RUSTFLAGS_MODULE) $(RUSTFLAGS_MODULE), \
+		$(KBUILD_RUSTFLAGS_KERNEL) $(RUSTFLAGS_KERNEL))
+
 modkern_aflags = $(if $(part-of-module),				\
 			$(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE),	\
 			$(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL))
@@ -211,6 +221,8 @@ c_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 		 $(_c_flags) $(modkern_cflags)                           \
 		 $(basename_flags) $(modname_flags)
 
+rust_flags     = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg
+
 a_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 		 $(_a_flags) $(modkern_aflags)
 
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 7f39599e9fae..670d7997a38b 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -39,11 +39,13 @@ quiet_cmd_ld_ko_o = LD [M]  $@
 
 quiet_cmd_btf_ko = BTF [M] $@
       cmd_btf_ko = 							\
-	if [ -f vmlinux ]; then						\
+	if [ ! -f vmlinux ]; then					\
+		printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
+	elif [ -n "$(CONFIG_RUST)" ] && $(srctree)/scripts/is_rust_module.sh $@; then 		\
+		printf "Skipping BTF generation for %s because it's a Rust module\n" $@ 1>&2; \
+	else								\
 		LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \
 		$(RESOLVE_BTFIDS) -b vmlinux $@; 			\
-	else								\
-		printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
 	fi;
 
 # Same as newer-prereqs, but allows to exclude specified extra dependencies
diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh
index f1952c522466..2401c86fcf53 100755
--- a/scripts/cc-version.sh
+++ b/scripts/cc-version.sh
@@ -1,13 +1,13 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 #
-# Print the compiler name and its version in a 5 or 6-digit form.
+# Print the C compiler name and its version in a 5 or 6-digit form.
 # Also, perform the minimum version check.
 
 set -e
 
-# Print the compiler name and some version components.
-get_compiler_info()
+# Print the C compiler name and some version components.
+get_c_compiler_info()
 {
 	cat <<- EOF | "$@" -E -P -x c - 2>/dev/null
 	#if defined(__clang__)
@@ -32,7 +32,7 @@ get_canonical_version()
 
 # $@ instead of $1 because multiple words might be given, e.g. CC="ccache gcc".
 orig_args="$@"
-set -- $(get_compiler_info "$@")
+set -- $(get_c_compiler_info "$@")
 
 name=$1
 
@@ -52,7 +52,7 @@ ICC)
 	min_version=$($min_tool_version icc)
 	;;
 *)
-	echo "$orig_args: unknown compiler" >&2
+	echo "$orig_args: unknown C compiler" >&2
 	exit 1
 	;;
 esac
@@ -62,7 +62,7 @@ min_cversion=$(get_canonical_version $min_version)
 
 if [ "$cversion" -lt "$min_cversion" ]; then
 	echo >&2 "***"
-	echo >&2 "*** Compiler is too old."
+	echo >&2 "*** C compiler is too old."
 	echo >&2 "***   Your $name version:    $version"
 	echo >&2 "***   Minimum $name version: $min_version"
 	echo >&2 "***"
diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
new file mode 100644
index 000000000000..c146a3407183
--- /dev/null
+++ b/scripts/generate_rust_target.rs
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The custom target specification file generator for `rustc`.
+//!
+//! To configure a target from scratch, a JSON-encoded file has to be passed
+//! to `rustc` (introduced in [RFC 131]). These options and the file itself are
+//! unstable. Eventually, `rustc` should provide a way to do this in a stable
+//! manner. For instance, via command-line arguments. Therefore, this file
+//! should avoid using keys which can be set via `-C` or `-Z` options.
+//!
+//! [RFC 131]: https://rust-lang.github.io/rfcs/0131-target-specification.html
+
+use std::{
+    collections::HashMap,
+    fmt::{Display, Formatter, Result},
+    io::BufRead,
+};
+
+enum Value {
+    Boolean(bool),
+    Number(i32),
+    String(String),
+    Object(Object),
+}
+
+type Object = Vec<(String, Value)>;
+
+/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
+/// enough for this purpose.
+impl Display for Value {
+    fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
+        match self {
+            Value::Boolean(boolean) => write!(formatter, "{}", boolean),
+            Value::Number(number) => write!(formatter, "{}", number),
+            Value::String(string) => write!(formatter, "\"{}\"", string),
+            Value::Object(object) => {
+                formatter.write_str("{")?;
+                if let [ref rest @ .., ref last] = object[..] {
+                    for (key, value) in rest {
+                        write!(formatter, "\"{}\": {},", key, value)?;
+                    }
+                    write!(formatter, "\"{}\": {}", last.0, last.1)?;
+                }
+                formatter.write_str("}")
+            }
+        }
+    }
+}
+
+struct TargetSpec(Object);
+
+impl TargetSpec {
+    fn new() -> TargetSpec {
+        TargetSpec(Vec::new())
+    }
+}
+
+trait Push<T> {
+    fn push(&mut self, key: &str, value: T);
+}
+
+impl Push<bool> for TargetSpec {
+    fn push(&mut self, key: &str, value: bool) {
+        self.0.push((key.to_string(), Value::Boolean(value)));
+    }
+}
+
+impl Push<i32> for TargetSpec {
+    fn push(&mut self, key: &str, value: i32) {
+        self.0.push((key.to_string(), Value::Number(value)));
+    }
+}
+
+impl Push<String> for TargetSpec {
+    fn push(&mut self, key: &str, value: String) {
+        self.0.push((key.to_string(), Value::String(value)));
+    }
+}
+
+impl Push<&str> for TargetSpec {
+    fn push(&mut self, key: &str, value: &str) {
+        self.push(key, value.to_string());
+    }
+}
+
+impl Push<Object> for TargetSpec {
+    fn push(&mut self, key: &str, value: Object) {
+        self.0.push((key.to_string(), Value::Object(value)));
+    }
+}
+
+impl Display for TargetSpec {
+    fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
+        // We add some newlines for clarity.
+        formatter.write_str("{\n")?;
+        if let [ref rest @ .., ref last] = self.0[..] {
+            for (key, value) in rest {
+                write!(formatter, "    \"{}\": {},\n", key, value)?;
+            }
+            write!(formatter, "    \"{}\": {}\n", last.0, last.1)?;
+        }
+        formatter.write_str("}")
+    }
+}
+
+struct KernelConfig(HashMap<String, String>);
+
+impl KernelConfig {
+    /// Parses `include/config/auto.conf` from `stdin`.
+    fn from_stdin() -> KernelConfig {
+        let mut result = HashMap::new();
+
+        let stdin = std::io::stdin();
+        let mut handle = stdin.lock();
+        let mut line = String::new();
+
+        loop {
+            line.clear();
+
+            if handle.read_line(&mut line).unwrap() == 0 {
+                break;
+            }
+
+            if line.starts_with('#') {
+                continue;
+            }
+
+            let (key, value) = line.split_once('=').expect("Missing `=` in line.");
+            result.insert(key.to_string(), value.trim_end_matches('\n').to_string());
+        }
+
+        KernelConfig(result)
+    }
+
+    /// Does the option exist in the configuration (any value)?
+    ///
+    /// The argument must be passed without the `CONFIG_` prefix.
+    /// This avoids repetition and it also avoids `fixdep` making us
+    /// depend on it.
+    fn has(&self, option: &str) -> bool {
+        let option = "CONFIG_".to_owned() + option;
+        self.0.contains_key(&option)
+    }
+}
+
+fn main() {
+    let cfg = KernelConfig::from_stdin();
+    let mut ts = TargetSpec::new();
+
+    // `llvm-target`s are taken from `scripts/Makefile.clang`.
+    if cfg.has("ARM") {
+        ts.push("arch", "arm");
+        ts.push(
+            "data-layout",
+            "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64",
+        );
+        ts.push("features", "+strict-align,+v6");
+        ts.push("llvm-target", "arm-linux-gnueabi");
+        ts.push("max-atomic-width", 64);
+        ts.push("target-mcount", "\\u0001__gnu_mcount_nc");
+        ts.push("target-pointer-width", "32");
+    } else if cfg.has("ARM64") {
+        ts.push("arch", "aarch64");
+        ts.push(
+            "data-layout",
+            "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128",
+        );
+        ts.push("disable-redzone", true);
+        ts.push("features", "+strict-align,-neon,-fp-armv8");
+        ts.push("llvm-target", "aarch64-linux-gnu");
+        ts.push("max-atomic-width", 128);
+        ts.push("target-pointer-width", "64");
+    } else if cfg.has("PPC") {
+        ts.push("arch", "powerpc64");
+        ts.push("code-model", "large");
+        ts.push("data-layout", "e-m:e-i64:64-n32:64");
+        ts.push("features", "-altivec,-vsx,-hard-float");
+        ts.push("llvm-target", "powerpc64le-linux-gnu");
+        ts.push("max-atomic-width", 64);
+        ts.push("target-mcount", "_mcount");
+        ts.push("target-pointer-width", "64");
+    } else if cfg.has("RISCV") {
+        if cfg.has("64BIT") {
+            ts.push("arch", "riscv64");
+            ts.push("data-layout", "e-m:e-p:64:64-i64:64-i128:128-n64-S128");
+            ts.push("llvm-target", "riscv64-linux-gnu");
+            ts.push("target-pointer-width", "64");
+        } else {
+            ts.push("arch", "riscv32");
+            ts.push("data-layout", "e-m:e-p:32:32-i64:64-n32-S128");
+            ts.push("llvm-target", "riscv32-linux-gnu");
+            ts.push("target-pointer-width", "32");
+        }
+        ts.push("code-model", "medium");
+        ts.push("disable-redzone", true);
+        let mut features = "+m,+a".to_string();
+        if cfg.has("RISCV_ISA_C") {
+            features += ",+c";
+        }
+        ts.push("features", features);
+    } else if cfg.has("X86_64") {
+        ts.push("arch", "x86_64");
+        ts.push(
+            "data-layout",
+            "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128",
+        );
+        ts.push("llvm-target", "x86_64-linux-gnu");
+        ts.push("target-pointer-width", "64");
+    } else {
+        panic!("Unsupported architecture");
+    }
+
+    ts.push("emit-debug-gdb-scripts", false);
+    ts.push("frame-pointer", "may-omit");
+    ts.push(
+        "stack-probes",
+        vec![("kind".to_string(), Value::String("none".to_string()))],
+    );
+
+    // Everything else is LE, whether `CPU_LITTLE_ENDIAN` is declared or not
+    // (e.g. x86). It is also `rustc`'s default.
+    if cfg.has("CPU_BIG_ENDIAN") {
+        ts.push("target-endian", "big");
+    }
+
+    println!("{}", ts);
+}
diff --git a/scripts/is_rust_module.sh b/scripts/is_rust_module.sh
new file mode 100755
index 000000000000..277a64d07f22
--- /dev/null
+++ b/scripts/is_rust_module.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# is_rust_module.sh module.ko
+#
+# Returns `0` if `module.ko` is a Rust module, `1` otherwise.
+
+set -e
+
+# Using the `16_` prefix ensures other symbols with the same substring
+# are not picked up (even if it would be unlikely). The last part is
+# used just in case LLVM decides to use the `.` suffix.
+${NM} "$*" | grep -qE '^[0-9a-fA-F]+ r _R[^[:space:]]+16___IS_RUST_MODULE[^[:space:]]*$'
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index c4340c90e172..b7c9f1dd5e42 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -216,6 +216,13 @@ static const char *conf_get_autoheader_name(void)
 	return name ? name : "include/generated/autoconf.h";
 }
 
+static const char *conf_get_rustccfg_name(void)
+{
+	char *name = getenv("KCONFIG_RUSTCCFG");
+
+	return name ? name : "include/generated/rustc_cfg";
+}
+
 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 {
 	char *p2;
@@ -605,6 +612,9 @@ static const struct comment_style comment_style_c = {
 
 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
 {
+	if (!cs)
+		return;
+
 	fprintf(fp, "%s\n", cs->prefix);
 
 	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
@@ -745,6 +755,65 @@ static void print_symbol_for_c(FILE *fp, struct symbol *sym)
 	free(escaped);
 }
 
+static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
+{
+	const char *val;
+	const char *val_prefix = "";
+	char *val_prefixed = NULL;
+	size_t val_prefixed_len;
+	char *escaped = NULL;
+
+	if (sym->type == S_UNKNOWN)
+		return;
+
+	val = sym_get_string_value(sym);
+
+	switch (sym->type) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		/*
+		 * We do not care about disabled ones, i.e. no need for
+		 * what otherwise are "comments" in other printers.
+		 */
+		if (*val == 'n')
+			return;
+
+		/*
+		 * To have similar functionality to the C macro `IS_ENABLED()`
+		 * we provide an empty `--cfg CONFIG_X` here in both `y`
+		 * and `m` cases.
+		 *
+		 * Then, the common `fprintf()` below will also give us
+		 * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
+		 * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
+		 */
+		fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
+		break;
+	case S_HEX:
+		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
+			val_prefix = "0x";
+		break;
+	default:
+		break;
+	}
+
+	if (strlen(val_prefix) > 0) {
+		val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
+		val_prefixed = xmalloc(val_prefixed_len);
+		snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
+		val = val_prefixed;
+	}
+
+	/* All values get escaped: the `--cfg` option only takes strings */
+	escaped = escape_string_value(val);
+	val = escaped;
+
+	fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
+
+	free(escaped);
+	free(val_prefixed);
+}
+
 /*
  * Write out a minimal config.
  * All values that has default values are skipped as this is redundant.
@@ -1132,6 +1201,12 @@ int conf_write_autoconf(int overwrite)
 	if (ret)
 		return ret;
 
+	ret = __conf_write_autoconf(conf_get_rustccfg_name(),
+				    print_symbol_for_rustccfg,
+				    NULL);
+	if (ret)
+		return ret;
+
 	/*
 	 * Create include/config/auto.conf. This must be the last step because
 	 * Kbuild has a dependency on auto.conf and this marks the successful
diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
index 7c20252a90c6..53fe64856015 100755
--- a/scripts/min-tool-version.sh
+++ b/scripts/min-tool-version.sh
@@ -31,6 +31,12 @@ llvm)
 		echo 11.0.0
 	fi
 	;;
+rustc)
+	echo 1.60.0
+	;;
+bindgen)
+	echo 0.56.0
+	;;
 *)
 	echo "$1: unknown tool" >&2
 	exit 1
diff --git a/scripts/rust-is-available-bindgen-libclang.h b/scripts/rust-is-available-bindgen-libclang.h
new file mode 100644
index 000000000000..0ef6db10d674
--- /dev/null
+++ b/scripts/rust-is-available-bindgen-libclang.h
@@ -0,0 +1,2 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#pragma message("clang version " __clang_version__)
diff --git a/scripts/rust-is-available.sh b/scripts/rust-is-available.sh
new file mode 100755
index 000000000000..6bd395167d0f
--- /dev/null
+++ b/scripts/rust-is-available.sh
@@ -0,0 +1,158 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Tests whether a suitable Rust toolchain is available.
+#
+# Pass `-v` for human output and more checks (as warnings).
+
+set -e
+
+min_tool_version=$(dirname $0)/min-tool-version.sh
+
+# Convert the version string x.y.z to a canonical up-to-7-digits form.
+#
+# Note that this function uses one more digit (compared to other
+# instances in other version scripts) to give a bit more space to
+# `rustc` since it will reach 1.100.0 in late 2026.
+get_canonical_version()
+{
+	IFS=.
+	set -- $1
+	echo $((100000 * $1 + 100 * $2 + $3))
+}
+
+# Check that the Rust compiler exists.
+if ! command -v "$RUSTC" >/dev/null; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust compiler '$RUSTC' could not be found."
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+
+# Check that the Rust bindings generator exists.
+if ! command -v "$BINDGEN" >/dev/null; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust bindings generator '$BINDGEN' could not be found."
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+
+# Check that the Rust compiler version is suitable.
+#
+# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
+rust_compiler_version=$( \
+	LC_ALL=C "$RUSTC" --version 2>/dev/null \
+		| head -n 1 \
+		| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+rust_compiler_min_version=$($min_tool_version rustc)
+rust_compiler_cversion=$(get_canonical_version $rust_compiler_version)
+rust_compiler_min_cversion=$(get_canonical_version $rust_compiler_min_version)
+if [ "$rust_compiler_cversion" -lt "$rust_compiler_min_cversion" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust compiler '$RUSTC' is too old."
+		echo >&2 "***   Your version:    $rust_compiler_version"
+		echo >&2 "***   Minimum version: $rust_compiler_min_version"
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+if [ "$1" = -v ] && [ "$rust_compiler_cversion" -gt "$rust_compiler_min_cversion" ]; then
+	echo >&2 "***"
+	echo >&2 "*** Rust compiler '$RUSTC' is too new. This may or may not work."
+	echo >&2 "***   Your version:     $rust_compiler_version"
+	echo >&2 "***   Expected version: $rust_compiler_min_version"
+	echo >&2 "***"
+fi
+
+# Check that the Rust bindings generator is suitable.
+#
+# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
+rust_bindings_generator_version=$( \
+	LC_ALL=C "$BINDGEN" --version 2>/dev/null \
+		| head -n 1 \
+		| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+rust_bindings_generator_min_version=$($min_tool_version bindgen)
+rust_bindings_generator_cversion=$(get_canonical_version $rust_bindings_generator_version)
+rust_bindings_generator_min_cversion=$(get_canonical_version $rust_bindings_generator_min_version)
+if [ "$rust_bindings_generator_cversion" -lt "$rust_bindings_generator_min_cversion" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust bindings generator '$BINDGEN' is too old."
+		echo >&2 "***   Your version:    $rust_bindings_generator_version"
+		echo >&2 "***   Minimum version: $rust_bindings_generator_min_version"
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+if [ "$1" = -v ] && [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cversion" ]; then
+	echo >&2 "***"
+	echo >&2 "*** Rust bindings generator '$BINDGEN' is too new. This may or may not work."
+	echo >&2 "***   Your version:     $rust_bindings_generator_version"
+	echo >&2 "***   Expected version: $rust_bindings_generator_min_version"
+	echo >&2 "***"
+fi
+
+# Check that the `libclang` used by the Rust bindings generator is suitable.
+bindgen_libclang_version=$( \
+	LC_ALL=C "$BINDGEN" $(dirname $0)/rust-is-available-bindgen-libclang.h 2>&1 >/dev/null \
+		| grep -F 'clang version ' \
+		| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+bindgen_libclang_min_version=$($min_tool_version llvm)
+bindgen_libclang_cversion=$(get_canonical_version $bindgen_libclang_version)
+bindgen_libclang_min_cversion=$(get_canonical_version $bindgen_libclang_min_version)
+if [ "$bindgen_libclang_cversion" -lt "$bindgen_libclang_min_cversion" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') is too old."
+		echo >&2 "***   Your version:    $bindgen_libclang_version"
+		echo >&2 "***   Minimum version: $bindgen_libclang_min_version"
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+
+# If the C compiler is Clang, then we can also check whether its version
+# matches the `libclang` version used by the Rust bindings generator.
+#
+# In the future, we might be able to perform a full version check, see
+# https://github.com/rust-lang/rust-bindgen/issues/2138.
+if [ "$1" = -v ]; then
+	cc_name=$($(dirname $0)/cc-version.sh "$CC" | cut -f1 -d' ')
+	if [ "$cc_name" = Clang ]; then
+		clang_version=$( \
+			LC_ALL=C "$CC" --version 2>/dev/null \
+				| sed -nE '1s:.*version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
+		)
+		if [ "$clang_version" != "$bindgen_libclang_version" ]; then
+			echo >&2 "***"
+			echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') version does not match Clang's. This may be a problem."
+			echo >&2 "***   libclang version: $bindgen_libclang_version"
+			echo >&2 "***   Clang version:    $clang_version"
+			echo >&2 "***"
+		fi
+	fi
+fi
+
+# Check that the source code for the `core` standard library exists.
+#
+# `$KRUSTFLAGS` is passed in case the user added `--sysroot`.
+rustc_sysroot=$("$RUSTC" $KRUSTFLAGS --print sysroot)
+rustc_src=${RUST_LIB_SRC:-"$rustc_sysroot/lib/rustlib/src/rust/library"}
+rustc_src_core="$rustc_src/core/src/lib.rs"
+if [ ! -e "$rustc_src_core" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Source code for the 'core' standard library could not be found"
+		echo >&2 "*** at '$rustc_src_core'."
+		echo >&2 "***"
+	fi
+	exit 1
+fi
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 22/25] samples: add Rust examples
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (17 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 23/25] MAINTAINERS: Rust Miguel Ojeda
                   ` (2 subsequent siblings)
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Alex Gaynor, Finn Behrens, Wedson Almeida Filho,
	Sven Van Asbroeck, Gary Guo, Boris-Chengbiao Zhou, Ayaan Zaidi,
	Milan Landaverde

A set of Rust modules that showcase how Rust modules look like
and how to use the abstracted kernel features, as well as
an example of a Rust host program with several modules.

These samples also double as tests in the CI.

The semaphore sample comes with a C version for comparison.

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Co-developed-by: Ayaan Zaidi <zaidi.ayaan@gmail.com>
Signed-off-by: Ayaan Zaidi <zaidi.ayaan@gmail.com>
Co-developed-by: Milan Landaverde <milan@mdaverde.com>
Signed-off-by: Milan Landaverde <milan@mdaverde.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 samples/Kconfig                        |   2 +
 samples/Makefile                       |   1 +
 samples/rust/Kconfig                   | 140 ++++++++++++++++
 samples/rust/Makefile                  |  16 ++
 samples/rust/hostprogs/.gitignore      |   3 +
 samples/rust/hostprogs/Makefile        |   5 +
 samples/rust/hostprogs/a.rs            |   7 +
 samples/rust/hostprogs/b.rs            |   5 +
 samples/rust/hostprogs/single.rs       |  12 ++
 samples/rust/rust_chrdev.rs            |  50 ++++++
 samples/rust/rust_minimal.rs           |  35 ++++
 samples/rust/rust_miscdev.rs           | 143 +++++++++++++++++
 samples/rust/rust_module_parameters.rs |  69 ++++++++
 samples/rust/rust_netfilter.rs         |  54 +++++++
 samples/rust/rust_platform.rs          |  22 +++
 samples/rust/rust_print.rs             |  54 +++++++
 samples/rust/rust_random.rs            |  60 +++++++
 samples/rust/rust_semaphore.rs         | 171 ++++++++++++++++++++
 samples/rust/rust_semaphore_c.c        | 212 +++++++++++++++++++++++++
 samples/rust/rust_stack_probing.rs     |  36 +++++
 samples/rust/rust_sync.rs              |  93 +++++++++++
 21 files changed, 1190 insertions(+)
 create mode 100644 samples/rust/Kconfig
 create mode 100644 samples/rust/Makefile
 create mode 100644 samples/rust/hostprogs/.gitignore
 create mode 100644 samples/rust/hostprogs/Makefile
 create mode 100644 samples/rust/hostprogs/a.rs
 create mode 100644 samples/rust/hostprogs/b.rs
 create mode 100644 samples/rust/hostprogs/single.rs
 create mode 100644 samples/rust/rust_chrdev.rs
 create mode 100644 samples/rust/rust_minimal.rs
 create mode 100644 samples/rust/rust_miscdev.rs
 create mode 100644 samples/rust/rust_module_parameters.rs
 create mode 100644 samples/rust/rust_netfilter.rs
 create mode 100644 samples/rust/rust_platform.rs
 create mode 100644 samples/rust/rust_print.rs
 create mode 100644 samples/rust/rust_random.rs
 create mode 100644 samples/rust/rust_semaphore.rs
 create mode 100644 samples/rust/rust_semaphore_c.c
 create mode 100644 samples/rust/rust_stack_probing.rs
 create mode 100644 samples/rust/rust_sync.rs

diff --git a/samples/Kconfig b/samples/Kconfig
index 470ee3baf2e1..0d81c00289ee 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -263,6 +263,8 @@ config SAMPLE_CORESIGHT_SYSCFG
 	  This demonstrates how a user may create their own CoreSight
 	  configurations and easily load them into the system at runtime.
 
+source "samples/rust/Kconfig"
+
 endif # SAMPLES
 
 config HAVE_SAMPLE_FTRACE_DIRECT
diff --git a/samples/Makefile b/samples/Makefile
index 701e912ab5af..9832ef3f8fcb 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -35,3 +35,4 @@ subdir-$(CONFIG_SAMPLE_WATCH_QUEUE)	+= watch_queue
 obj-$(CONFIG_DEBUG_KMEMLEAK_TEST)	+= kmemleak/
 obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
 obj-$(CONFIG_SAMPLE_FPROBE)		+= fprobe/
+obj-$(CONFIG_SAMPLES_RUST)		+= rust/
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
new file mode 100644
index 000000000000..4f90f8d69351
--- /dev/null
+++ b/samples/rust/Kconfig
@@ -0,0 +1,140 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig SAMPLES_RUST
+	bool "Rust samples"
+	depends on RUST
+	help
+	  You can build sample Rust kernel code here.
+
+	  If unsure, say N.
+
+if SAMPLES_RUST
+
+config SAMPLE_RUST_MINIMAL
+	tristate "Minimal"
+	help
+	  This option builds the Rust minimal module sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_minimal.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_PRINT
+	tristate "Printing macros"
+	help
+	  This option builds the Rust printing macros sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_print.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_MODULE_PARAMETERS
+	tristate "Module parameters"
+	help
+	  This option builds the Rust module parameters sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_module_parameters.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SYNC
+	tristate "Synchronisation primitives"
+	help
+	  This option builds the Rust synchronisation primitives sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_sync.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_CHRDEV
+	tristate "Character device"
+	help
+	  This option builds the Rust character device sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_chrdev.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_MISCDEV
+	tristate "Miscellaneous device"
+	help
+	  This option builds the Rust miscellaneous device sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_miscdev.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_STACK_PROBING
+	tristate "Stack probing"
+	help
+	  This option builds the Rust stack probing sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_stack_probing.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SEMAPHORE
+	tristate "Semaphore"
+	help
+	  This option builds the Rust semaphore sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_semaphore.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SEMAPHORE_C
+	tristate "Semaphore (in C, for comparison)"
+	help
+	  This option builds the Rust semaphore sample (in C, for comparison).
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_semaphore_c.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_RANDOM
+	tristate "Random"
+	help
+	  This option builds the Rust random sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_random.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_PLATFORM
+	tristate "Platform device driver"
+	help
+	  This option builds the Rust platform device driver sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_platform.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_NETFILTER
+	tristate "Network filter module"
+	help
+	  This option builds the Rust netfilter module sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_netfilter.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_HOSTPROGS
+	bool "Host programs"
+	help
+	  This option builds the Rust host program samples.
+
+	  If unsure, say N.
+
+endif # SAMPLES_RUST
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
new file mode 100644
index 000000000000..fb5a205ebb8c
--- /dev/null
+++ b/samples/rust/Makefile
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
+obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_MODULE_PARAMETERS)	+= rust_module_parameters.o
+obj-$(CONFIG_SAMPLE_RUST_SYNC)			+= rust_sync.o
+obj-$(CONFIG_SAMPLE_RUST_CHRDEV)		+= rust_chrdev.o
+obj-$(CONFIG_SAMPLE_RUST_MISCDEV)		+= rust_miscdev.o
+obj-$(CONFIG_SAMPLE_RUST_STACK_PROBING)		+= rust_stack_probing.o
+obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE)		+= rust_semaphore.o
+obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE_C)		+= rust_semaphore_c.o
+obj-$(CONFIG_SAMPLE_RUST_RANDOM)		+= rust_random.o
+obj-$(CONFIG_SAMPLE_RUST_PLATFORM)		+= rust_platform.o
+obj-$(CONFIG_SAMPLE_RUST_NETFILTER)		+= rust_netfilter.o
+
+subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
diff --git a/samples/rust/hostprogs/.gitignore b/samples/rust/hostprogs/.gitignore
new file mode 100644
index 000000000000..a6c173da5048
--- /dev/null
+++ b/samples/rust/hostprogs/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+single
diff --git a/samples/rust/hostprogs/Makefile b/samples/rust/hostprogs/Makefile
new file mode 100644
index 000000000000..8ddcbd7416db
--- /dev/null
+++ b/samples/rust/hostprogs/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+hostprogs-always-y := single
+
+single-rust := y
diff --git a/samples/rust/hostprogs/a.rs b/samples/rust/hostprogs/a.rs
new file mode 100644
index 000000000000..f7a4a3d0f4e0
--- /dev/null
+++ b/samples/rust/hostprogs/a.rs
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample: module `a`.
+
+pub(crate) fn f(x: i32) {
+    println!("The number is {}.", x);
+}
diff --git a/samples/rust/hostprogs/b.rs b/samples/rust/hostprogs/b.rs
new file mode 100644
index 000000000000..c1675890648f
--- /dev/null
+++ b/samples/rust/hostprogs/b.rs
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample: module `b`.
+
+pub(crate) const CONSTANT: i32 = 42;
diff --git a/samples/rust/hostprogs/single.rs b/samples/rust/hostprogs/single.rs
new file mode 100644
index 000000000000..8c48a119339a
--- /dev/null
+++ b/samples/rust/hostprogs/single.rs
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample.
+
+mod a;
+mod b;
+
+fn main() {
+    println!("Hello world!");
+
+    a::f(b::CONSTANT);
+}
diff --git a/samples/rust/rust_chrdev.rs b/samples/rust/rust_chrdev.rs
new file mode 100644
index 000000000000..9f5d564671ea
--- /dev/null
+++ b/samples/rust/rust_chrdev.rs
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust character device sample.
+
+use kernel::prelude::*;
+use kernel::{chrdev, file};
+
+module! {
+    type: RustChrdev,
+    name: b"rust_chrdev",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust character device sample",
+    license: b"GPL",
+}
+
+struct RustFile;
+
+impl file::Operations for RustFile {
+    kernel::declare_file_operations!();
+
+    fn open(_shared: &(), _file: &file::File) -> Result {
+        Ok(())
+    }
+}
+
+struct RustChrdev {
+    _dev: Pin<Box<chrdev::Registration<2>>>,
+}
+
+impl kernel::Module for RustChrdev {
+    fn init(name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust character device sample (init)\n");
+
+        let mut chrdev_reg = chrdev::Registration::new_pinned(name, 0, module)?;
+
+        // Register the same kind of device twice, we're just demonstrating
+        // that you can use multiple minors. There are two minors in this case
+        // because its type is `chrdev::Registration<2>`
+        chrdev_reg.as_mut().register::<RustFile>()?;
+        chrdev_reg.as_mut().register::<RustFile>()?;
+
+        Ok(RustChrdev { _dev: chrdev_reg })
+    }
+}
+
+impl Drop for RustChrdev {
+    fn drop(&mut self) {
+        pr_info!("Rust character device sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs
new file mode 100644
index 000000000000..6e1a926c6f62
--- /dev/null
+++ b/samples/rust/rust_minimal.rs
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust minimal sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: RustMinimal,
+    name: b"rust_minimal",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust minimal sample",
+    license: b"GPL",
+}
+
+struct RustMinimal {
+    message: String,
+}
+
+impl kernel::Module for RustMinimal {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust minimal sample (init)\n");
+        pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
+
+        Ok(RustMinimal {
+            message: "on the heap!".try_to_owned()?,
+        })
+    }
+}
+
+impl Drop for RustMinimal {
+    fn drop(&mut self) {
+        pr_info!("My message is {}\n", self.message);
+        pr_info!("Rust minimal sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_miscdev.rs b/samples/rust/rust_miscdev.rs
new file mode 100644
index 000000000000..d1bf3c61f5ce
--- /dev/null
+++ b/samples/rust/rust_miscdev.rs
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust miscellaneous device sample.
+
+use kernel::prelude::*;
+use kernel::{
+    file::{self, File},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    miscdev,
+    sync::{CondVar, Mutex, Ref, RefBorrow, UniqueRef},
+};
+
+module! {
+    type: RustMiscdev,
+    name: b"rust_miscdev",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust miscellaneous device sample",
+    license: b"GPL",
+}
+
+const MAX_TOKENS: usize = 3;
+
+struct SharedStateInner {
+    token_count: usize,
+}
+
+struct SharedState {
+    state_changed: CondVar,
+    inner: Mutex<SharedStateInner>,
+}
+
+impl SharedState {
+    fn try_new() -> Result<Ref<Self>> {
+        let mut state = Pin::from(UniqueRef::try_new(Self {
+            // SAFETY: `condvar_init!` is called below.
+            state_changed: unsafe { CondVar::new() },
+            // SAFETY: `mutex_init!` is called below.
+            inner: unsafe { Mutex::new(SharedStateInner { token_count: 0 }) },
+        })?);
+
+        // SAFETY: `state_changed` is pinned when `state` is.
+        let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.state_changed) };
+        kernel::condvar_init!(pinned, "SharedState::state_changed");
+
+        // SAFETY: `inner` is pinned when `state` is.
+        let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.inner) };
+        kernel::mutex_init!(pinned, "SharedState::inner");
+
+        Ok(state.into())
+    }
+}
+
+struct Token;
+impl file::Operations for Token {
+    type Data = Ref<SharedState>;
+    type OpenData = Ref<SharedState>;
+
+    kernel::declare_file_operations!(read, write);
+
+    fn open(shared: &Ref<SharedState>, _file: &File) -> Result<Self::Data> {
+        Ok(shared.clone())
+    }
+
+    fn read(
+        shared: RefBorrow<'_, SharedState>,
+        _: &File,
+        data: &mut impl IoBufferWriter,
+        offset: u64,
+    ) -> Result<usize> {
+        // Succeed if the caller doesn't provide a buffer or if not at the start.
+        if data.is_empty() || offset != 0 {
+            return Ok(0);
+        }
+
+        {
+            let mut inner = shared.inner.lock();
+
+            // Wait until we are allowed to decrement the token count or a signal arrives.
+            while inner.token_count == 0 {
+                if shared.state_changed.wait(&mut inner) {
+                    return Err(EINTR);
+                }
+            }
+
+            // Consume a token.
+            inner.token_count -= 1;
+        }
+
+        // Notify a possible writer waiting.
+        shared.state_changed.notify_all();
+
+        // Write a one-byte 1 to the reader.
+        data.write_slice(&[1u8; 1])?;
+        Ok(1)
+    }
+
+    fn write(
+        shared: RefBorrow<'_, SharedState>,
+        _: &File,
+        data: &mut impl IoBufferReader,
+        _offset: u64,
+    ) -> Result<usize> {
+        {
+            let mut inner = shared.inner.lock();
+
+            // Wait until we are allowed to increment the token count or a signal arrives.
+            while inner.token_count == MAX_TOKENS {
+                if shared.state_changed.wait(&mut inner) {
+                    return Err(EINTR);
+                }
+            }
+
+            // Increment the number of token so that a reader can be released.
+            inner.token_count += 1;
+        }
+
+        // Notify a possible reader waiting.
+        shared.state_changed.notify_all();
+        Ok(data.len())
+    }
+}
+
+struct RustMiscdev {
+    _dev: Pin<Box<miscdev::Registration<Token>>>,
+}
+
+impl kernel::Module for RustMiscdev {
+    fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust miscellaneous device sample (init)\n");
+
+        let state = SharedState::try_new()?;
+
+        Ok(RustMiscdev {
+            _dev: miscdev::Registration::new_pinned(fmt!("{name}"), state)?,
+        })
+    }
+}
+
+impl Drop for RustMiscdev {
+    fn drop(&mut self) {
+        pr_info!("Rust miscellaneous device sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_module_parameters.rs b/samples/rust/rust_module_parameters.rs
new file mode 100644
index 000000000000..12fe5e738e83
--- /dev/null
+++ b/samples/rust/rust_module_parameters.rs
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust module parameters sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: RustModuleParameters,
+    name: b"rust_module_parameters",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust module parameters sample",
+    license: b"GPL",
+    params: {
+        my_bool: bool {
+            default: true,
+            permissions: 0,
+            description: b"Example of bool",
+        },
+        my_i32: i32 {
+            default: 42,
+            permissions: 0o644,
+            description: b"Example of i32",
+        },
+        my_str: str {
+            default: b"default str val",
+            permissions: 0o644,
+            description: b"Example of a string param",
+        },
+        my_usize: usize {
+            default: 42,
+            permissions: 0o644,
+            description: b"Example of usize",
+        },
+        my_array: ArrayParam<i32, 3> {
+            default: [0, 1],
+            permissions: 0,
+            description: b"Example of array",
+        },
+    },
+}
+
+struct RustModuleParameters;
+
+impl kernel::Module for RustModuleParameters {
+    fn init(_name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust module parameters sample (init)\n");
+
+        {
+            let lock = module.kernel_param_lock();
+            pr_info!("Parameters:\n");
+            pr_info!("  my_bool:    {}\n", my_bool.read());
+            pr_info!("  my_i32:     {}\n", my_i32.read(&lock));
+            pr_info!(
+                "  my_str:     {}\n",
+                core::str::from_utf8(my_str.read(&lock))?
+            );
+            pr_info!("  my_usize:   {}\n", my_usize.read(&lock));
+            pr_info!("  my_array:   {:?}\n", my_array.read());
+        }
+
+        Ok(RustModuleParameters)
+    }
+}
+
+impl Drop for RustModuleParameters {
+    fn drop(&mut self) {
+        pr_info!("Rust module parameters sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_netfilter.rs b/samples/rust/rust_netfilter.rs
new file mode 100644
index 000000000000..4bd5c07fee8c
--- /dev/null
+++ b/samples/rust/rust_netfilter.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust netfilter sample.
+
+use kernel::net;
+use kernel::net::filter::{self as netfilter, inet, Disposition, Family};
+use kernel::prelude::*;
+
+module! {
+    type: RustNetfilter,
+    name: b"rust_netfilter",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust netfilter sample",
+    license: b"GPL",
+}
+
+struct RustNetfilter {
+    _in: Pin<Box<netfilter::Registration<Self>>>,
+    _out: Pin<Box<netfilter::Registration<Self>>>,
+}
+
+impl netfilter::Filter for RustNetfilter {
+    fn filter(_: (), skb: &net::SkBuff) -> Disposition {
+        let data = skb.head_data();
+        pr_info!(
+            "packet headlen={}, len={}, first bytes={:02x?}\n",
+            data.len(),
+            skb.len(),
+            &data[..core::cmp::min(10, data.len())]
+        );
+        Disposition::Accept
+    }
+}
+
+impl kernel::Module for RustNetfilter {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        Ok(Self {
+            _in: netfilter::Registration::new_pinned(
+                Family::INet(inet::Hook::PreRouting),
+                0,
+                net::init_ns().into(),
+                None,
+                (),
+            )?,
+            _out: netfilter::Registration::new_pinned(
+                Family::INet(inet::Hook::PostRouting),
+                0,
+                net::init_ns().into(),
+                None,
+                (),
+            )?,
+        })
+    }
+}
diff --git a/samples/rust/rust_platform.rs b/samples/rust/rust_platform.rs
new file mode 100644
index 000000000000..f62784676919
--- /dev/null
+++ b/samples/rust/rust_platform.rs
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust platform device driver sample.
+
+use kernel::{module_platform_driver, of, platform, prelude::*};
+
+module_platform_driver! {
+    type: Driver,
+    name: b"rust_platform",
+    license: b"GPL",
+}
+
+struct Driver;
+impl platform::Driver for Driver {
+    kernel::define_of_id_table! {(), [
+        (of::DeviceId::Compatible(b"rust,sample"), None),
+    ]}
+
+    fn probe(_dev: &mut platform::Device, _id_info: Option<&Self::IdInfo>) -> Result {
+        Ok(())
+    }
+}
diff --git a/samples/rust/rust_print.rs b/samples/rust/rust_print.rs
new file mode 100644
index 000000000000..30d96e025d89
--- /dev/null
+++ b/samples/rust/rust_print.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust printing macros sample.
+
+use kernel::prelude::*;
+use kernel::{pr_cont, str::CStr, ThisModule};
+
+module! {
+    type: RustPrint,
+    name: b"rust_print",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust printing macros sample",
+    license: b"GPL",
+}
+
+struct RustPrint;
+
+impl kernel::Module for RustPrint {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust printing macros sample (init)\n");
+
+        pr_emerg!("Emergency message (level 0) without args\n");
+        pr_alert!("Alert message (level 1) without args\n");
+        pr_crit!("Critical message (level 2) without args\n");
+        pr_err!("Error message (level 3) without args\n");
+        pr_warn!("Warning message (level 4) without args\n");
+        pr_notice!("Notice message (level 5) without args\n");
+        pr_info!("Info message (level 6) without args\n");
+
+        pr_info!("A line that");
+        pr_cont!(" is continued");
+        pr_cont!(" without args\n");
+
+        pr_emerg!("{} message (level {}) with args\n", "Emergency", 0);
+        pr_alert!("{} message (level {}) with args\n", "Alert", 1);
+        pr_crit!("{} message (level {}) with args\n", "Critical", 2);
+        pr_err!("{} message (level {}) with args\n", "Error", 3);
+        pr_warn!("{} message (level {}) with args\n", "Warning", 4);
+        pr_notice!("{} message (level {}) with args\n", "Notice", 5);
+        pr_info!("{} message (level {}) with args\n", "Info", 6);
+
+        pr_info!("A {} that", "line");
+        pr_cont!(" is {}", "continued");
+        pr_cont!(" with {}\n", "args");
+
+        Ok(RustPrint)
+    }
+}
+
+impl Drop for RustPrint {
+    fn drop(&mut self) {
+        pr_info!("Rust printing macros sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_random.rs b/samples/rust/rust_random.rs
new file mode 100644
index 000000000000..8ec87119aa9b
--- /dev/null
+++ b/samples/rust/rust_random.rs
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust random device.
+//!
+//! Adapted from Alex Gaynor's original available at
+//! <https://github.com/alex/just-use/blob/master/src/lib.rs>.
+
+use kernel::{
+    file::{self, File},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    prelude::*,
+};
+
+module_misc_device! {
+    type: RandomFile,
+    name: b"rust_random",
+    author: b"Rust for Linux Contributors",
+    description: b"Just use /dev/urandom: Now with early-boot safety",
+    license: b"GPL",
+}
+
+struct RandomFile;
+
+impl file::Operations for RandomFile {
+    kernel::declare_file_operations!(read, write, read_iter, write_iter);
+
+    fn open(_data: &(), _file: &File) -> Result {
+        Ok(())
+    }
+
+    fn read(_this: (), file: &File, buf: &mut impl IoBufferWriter, _: u64) -> Result<usize> {
+        let total_len = buf.len();
+        let mut chunkbuf = [0; 256];
+
+        while !buf.is_empty() {
+            let len = chunkbuf.len().min(buf.len());
+            let chunk = &mut chunkbuf[0..len];
+
+            if file.is_blocking() {
+                kernel::random::getrandom(chunk)?;
+            } else {
+                kernel::random::getrandom_nonblock(chunk)?;
+            }
+            buf.write_slice(chunk)?;
+        }
+        Ok(total_len)
+    }
+
+    fn write(_this: (), _file: &File, buf: &mut impl IoBufferReader, _: u64) -> Result<usize> {
+        let total_len = buf.len();
+        let mut chunkbuf = [0; 256];
+        while !buf.is_empty() {
+            let len = chunkbuf.len().min(buf.len());
+            let chunk = &mut chunkbuf[0..len];
+            buf.read_slice(chunk)?;
+            kernel::random::add_randomness(chunk);
+        }
+        Ok(total_len)
+    }
+}
diff --git a/samples/rust/rust_semaphore.rs b/samples/rust/rust_semaphore.rs
new file mode 100644
index 000000000000..702ac1fcb48a
--- /dev/null
+++ b/samples/rust/rust_semaphore.rs
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust semaphore sample.
+//!
+//! A counting semaphore that can be used by userspace.
+//!
+//! The count is incremented by writes to the device. A write of `n` bytes results in an increment
+//! of `n`. It is decremented by reads; each read results in the count being decremented by 1. If
+//! the count is already zero, a read will block until another write increments it.
+//!
+//! This can be used in user space from the shell for example  as follows (assuming a node called
+//! `semaphore`): `cat semaphore` decrements the count by 1 (waiting for it to become non-zero
+//! before decrementing); `echo -n 123 > semaphore` increments the semaphore by 3, potentially
+//! unblocking up to 3 blocked readers.
+
+use core::sync::atomic::{AtomicU64, Ordering};
+use kernel::{
+    condvar_init, declare_file_operations,
+    file::{self, File, IoctlCommand, IoctlHandler},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    miscdev::Registration,
+    mutex_init,
+    prelude::*,
+    sync::{CondVar, Mutex, Ref, UniqueRef},
+    user_ptr::{UserSlicePtrReader, UserSlicePtrWriter},
+};
+
+module! {
+    type: RustSemaphore,
+    name: b"rust_semaphore",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust semaphore sample",
+    license: b"GPL",
+}
+
+struct SemaphoreInner {
+    count: usize,
+    max_seen: usize,
+}
+
+struct Semaphore {
+    changed: CondVar,
+    inner: Mutex<SemaphoreInner>,
+}
+
+struct FileState {
+    read_count: AtomicU64,
+    shared: Ref<Semaphore>,
+}
+
+impl FileState {
+    fn consume(&self) -> Result {
+        let mut inner = self.shared.inner.lock();
+        while inner.count == 0 {
+            if self.shared.changed.wait(&mut inner) {
+                return Err(EINTR);
+            }
+        }
+        inner.count -= 1;
+        Ok(())
+    }
+}
+
+impl file::Operations for FileState {
+    type Data = Box<Self>;
+    type OpenData = Ref<Semaphore>;
+
+    declare_file_operations!(read, write, ioctl);
+
+    fn open(shared: &Ref<Semaphore>, _file: &File) -> Result<Box<Self>> {
+        Ok(Box::try_new(Self {
+            read_count: AtomicU64::new(0),
+            shared: shared.clone(),
+        })?)
+    }
+
+    fn read(this: &Self, _: &File, data: &mut impl IoBufferWriter, offset: u64) -> Result<usize> {
+        if data.is_empty() || offset > 0 {
+            return Ok(0);
+        }
+        this.consume()?;
+        data.write_slice(&[0u8; 1])?;
+        this.read_count.fetch_add(1, Ordering::Relaxed);
+        Ok(1)
+    }
+
+    fn write(this: &Self, _: &File, data: &mut impl IoBufferReader, _offs: u64) -> Result<usize> {
+        {
+            let mut inner = this.shared.inner.lock();
+            inner.count = inner.count.saturating_add(data.len());
+            if inner.count > inner.max_seen {
+                inner.max_seen = inner.count;
+            }
+        }
+
+        this.shared.changed.notify_all();
+        Ok(data.len())
+    }
+
+    fn ioctl(this: &Self, file: &File, cmd: &mut IoctlCommand) -> Result<i32> {
+        cmd.dispatch::<Self>(this, file)
+    }
+}
+
+struct RustSemaphore {
+    _dev: Pin<Box<Registration<FileState>>>,
+}
+
+impl kernel::Module for RustSemaphore {
+    fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust semaphore sample (init)\n");
+
+        let mut sema = Pin::from(UniqueRef::try_new(Semaphore {
+            // SAFETY: `condvar_init!` is called below.
+            changed: unsafe { CondVar::new() },
+
+            // SAFETY: `mutex_init!` is called below.
+            inner: unsafe {
+                Mutex::new(SemaphoreInner {
+                    count: 0,
+                    max_seen: 0,
+                })
+            },
+        })?);
+
+        // SAFETY: `changed` is pinned when `sema` is.
+        let pinned = unsafe { sema.as_mut().map_unchecked_mut(|s| &mut s.changed) };
+        condvar_init!(pinned, "Semaphore::changed");
+
+        // SAFETY: `inner` is pinned when `sema` is.
+        let pinned = unsafe { sema.as_mut().map_unchecked_mut(|s| &mut s.inner) };
+        mutex_init!(pinned, "Semaphore::inner");
+
+        Ok(Self {
+            _dev: Registration::new_pinned(fmt!("{name}"), sema.into())?,
+        })
+    }
+}
+
+impl Drop for RustSemaphore {
+    fn drop(&mut self) {
+        pr_info!("Rust semaphore sample (exit)\n");
+    }
+}
+
+const IOCTL_GET_READ_COUNT: u32 = 0x80086301;
+const IOCTL_SET_READ_COUNT: u32 = 0x40086301;
+
+impl IoctlHandler for FileState {
+    type Target<'a> = &'a Self;
+
+    fn read(this: &Self, _: &File, cmd: u32, writer: &mut UserSlicePtrWriter) -> Result<i32> {
+        match cmd {
+            IOCTL_GET_READ_COUNT => {
+                writer.write(&this.read_count.load(Ordering::Relaxed))?;
+                Ok(0)
+            }
+            _ => Err(EINVAL),
+        }
+    }
+
+    fn write(this: &Self, _: &File, cmd: u32, reader: &mut UserSlicePtrReader) -> Result<i32> {
+        match cmd {
+            IOCTL_SET_READ_COUNT => {
+                this.read_count.store(reader.read()?, Ordering::Relaxed);
+                Ok(0)
+            }
+            _ => Err(EINVAL),
+        }
+    }
+}
diff --git a/samples/rust/rust_semaphore_c.c b/samples/rust/rust_semaphore_c.c
new file mode 100644
index 000000000000..7672b0b4c105
--- /dev/null
+++ b/samples/rust/rust_semaphore_c.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Rust semaphore sample (in C, for comparison)
+ *
+ * This is a C implementation of `rust_semaphore.rs`. Refer to the description
+ * in that file for details on the device.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/refcount.h>
+#include <linux/wait.h>
+
+#define IOCTL_GET_READ_COUNT _IOR('c', 1, u64)
+#define IOCTL_SET_READ_COUNT _IOW('c', 1, u64)
+
+struct semaphore_state {
+	struct kref ref;
+	struct miscdevice miscdev;
+	wait_queue_head_t changed;
+	struct mutex mutex;
+	size_t count;
+	size_t max_seen;
+};
+
+struct file_state {
+	atomic64_t read_count;
+	struct semaphore_state *shared;
+};
+
+static int semaphore_consume(struct semaphore_state *state)
+{
+	DEFINE_WAIT(wait);
+
+	mutex_lock(&state->mutex);
+	while (state->count == 0) {
+		prepare_to_wait(&state->changed, &wait, TASK_INTERRUPTIBLE);
+		mutex_unlock(&state->mutex);
+		schedule();
+		finish_wait(&state->changed, &wait);
+		if (signal_pending(current))
+			return -EINTR;
+		mutex_lock(&state->mutex);
+	}
+
+	state->count--;
+	mutex_unlock(&state->mutex);
+
+	return 0;
+}
+
+static int semaphore_open(struct inode *nodp, struct file *filp)
+{
+	struct semaphore_state *shared =
+		container_of(filp->private_data, struct semaphore_state, miscdev);
+	struct file_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	kref_get(&shared->ref);
+	state->shared = shared;
+	atomic64_set(&state->read_count, 0);
+
+	filp->private_data = state;
+
+	return 0;
+}
+
+static ssize_t semaphore_write(struct file *filp, const char __user *buffer, size_t count,
+			       loff_t *ppos)
+{
+	struct file_state *state = filp->private_data;
+	struct semaphore_state *shared = state->shared;
+
+	mutex_lock(&shared->mutex);
+
+	shared->count += count;
+	if (shared->count < count)
+		shared->count = SIZE_MAX;
+
+	if (shared->count > shared->max_seen)
+		shared->max_seen = shared->count;
+
+	mutex_unlock(&shared->mutex);
+
+	wake_up_all(&shared->changed);
+
+	return count;
+}
+
+static ssize_t semaphore_read(struct file *filp, char __user *buffer,
+			      size_t count, loff_t *ppos)
+{
+	struct file_state *state = filp->private_data;
+	char c = 0;
+	int ret;
+
+	if (count == 0 || *ppos > 0)
+		return 0;
+
+	ret = semaphore_consume(state->shared);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(buffer, &c, sizeof(c)))
+		return -EFAULT;
+
+	atomic64_add(1, &state->read_count);
+	*ppos += 1;
+	return 1;
+}
+
+static long semaphore_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct file_state *state = filp->private_data;
+	void __user *buffer = (void __user *)arg;
+	u64 value;
+
+	switch (cmd) {
+	case IOCTL_GET_READ_COUNT:
+		value = atomic64_read(&state->read_count);
+		if (copy_to_user(buffer, &value, sizeof(value)))
+			return -EFAULT;
+		return 0;
+	case IOCTL_SET_READ_COUNT:
+		if (copy_from_user(&value, buffer, sizeof(value)))
+			return -EFAULT;
+		atomic64_set(&state->read_count, value);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static void semaphore_free(struct kref *kref)
+{
+	struct semaphore_state *device;
+
+	device = container_of(kref, struct semaphore_state, ref);
+	kfree(device);
+}
+
+static int semaphore_release(struct inode *nodp, struct file *filp)
+{
+	struct file_state *state = filp->private_data;
+
+	kref_put(&state->shared->ref, semaphore_free);
+	kfree(state);
+	return 0;
+}
+
+static const struct file_operations semaphore_fops = {
+	.owner = THIS_MODULE,
+	.open = semaphore_open,
+	.read = semaphore_read,
+	.write = semaphore_write,
+	.compat_ioctl = semaphore_ioctl,
+	.release = semaphore_release,
+};
+
+static struct semaphore_state *device;
+
+static int __init semaphore_init(void)
+{
+	int ret;
+	struct semaphore_state *state;
+
+	pr_info("Rust semaphore sample (in C, for comparison) (init)\n");
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	mutex_init(&state->mutex);
+	kref_init(&state->ref);
+	init_waitqueue_head(&state->changed);
+
+	state->miscdev.fops = &semaphore_fops;
+	state->miscdev.minor = MISC_DYNAMIC_MINOR;
+	state->miscdev.name = "semaphore";
+
+	ret = misc_register(&state->miscdev);
+	if (ret < 0) {
+		kfree(state);
+		return ret;
+	}
+
+	device = state;
+
+	return 0;
+}
+
+static void __exit semaphore_exit(void)
+{
+	pr_info("Rust semaphore sample (in C, for comparison) (exit)\n");
+
+	misc_deregister(&device->miscdev);
+	kref_put(&device->ref, semaphore_free);
+}
+
+module_init(semaphore_init);
+module_exit(semaphore_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rust for Linux Contributors");
+MODULE_DESCRIPTION("Rust semaphore sample (in C, for comparison)");
diff --git a/samples/rust/rust_stack_probing.rs b/samples/rust/rust_stack_probing.rs
new file mode 100644
index 000000000000..1448fe8e1b56
--- /dev/null
+++ b/samples/rust/rust_stack_probing.rs
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust stack probing sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: RustStackProbing,
+    name: b"rust_stack_probing",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust stack probing sample",
+    license: b"GPL",
+}
+
+struct RustStackProbing;
+
+impl kernel::Module for RustStackProbing {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust stack probing sample (init)\n");
+
+        // Including this large variable on the stack will trigger
+        // stack probing on the supported archs.
+        // This will verify that stack probing does not lead to
+        // any errors if we need to link `__rust_probestack`.
+        let x: [u64; 514] = core::hint::black_box([5; 514]);
+        pr_info!("Large array has length: {}\n", x.len());
+
+        Ok(RustStackProbing)
+    }
+}
+
+impl Drop for RustStackProbing {
+    fn drop(&mut self) {
+        pr_info!("Rust stack probing sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_sync.rs b/samples/rust/rust_sync.rs
new file mode 100644
index 000000000000..46637ace2f7f
--- /dev/null
+++ b/samples/rust/rust_sync.rs
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust synchronisation primitives sample.
+
+use kernel::prelude::*;
+use kernel::{
+    condvar_init, mutex_init, spinlock_init,
+    sync::{CondVar, Mutex, SpinLock},
+};
+
+module! {
+    type: RustSync,
+    name: b"rust_sync",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust synchronisation primitives sample",
+    license: b"GPL",
+}
+
+kernel::init_static_sync! {
+    static SAMPLE_MUTEX: Mutex<u32> = 10;
+    static SAMPLE_CONDVAR: CondVar;
+}
+
+struct RustSync;
+
+impl kernel::Module for RustSync {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust synchronisation primitives sample (init)\n");
+
+        // Test mutexes.
+        {
+            // SAFETY: `init` is called below.
+            let mut data = Pin::from(Box::try_new(unsafe { Mutex::new(0) })?);
+            mutex_init!(data.as_mut(), "RustSync::init::data1");
+            *data.lock() = 10;
+            pr_info!("Value: {}\n", *data.lock());
+
+            // SAFETY: `init` is called below.
+            let mut cv = Pin::from(Box::try_new(unsafe { CondVar::new() })?);
+            condvar_init!(cv.as_mut(), "RustSync::init::cv1");
+
+            {
+                let mut guard = data.lock();
+                while *guard != 10 {
+                    let _ = cv.wait(&mut guard);
+                }
+            }
+            cv.notify_one();
+            cv.notify_all();
+            cv.free_waiters();
+        }
+
+        // Test static mutex + condvar.
+        *SAMPLE_MUTEX.lock() = 20;
+
+        {
+            let mut guard = SAMPLE_MUTEX.lock();
+            while *guard != 20 {
+                let _ = SAMPLE_CONDVAR.wait(&mut guard);
+            }
+        }
+
+        // Test spinlocks.
+        {
+            // SAFETY: `init` is called below.
+            let mut data = Pin::from(Box::try_new(unsafe { SpinLock::new(0) })?);
+            spinlock_init!(data.as_mut(), "RustSync::init::data2");
+            *data.lock() = 10;
+            pr_info!("Value: {}\n", *data.lock());
+
+            // SAFETY: `init` is called below.
+            let mut cv = Pin::from(Box::try_new(unsafe { CondVar::new() })?);
+            condvar_init!(cv.as_mut(), "RustSync::init::cv2");
+            {
+                let mut guard = data.lock();
+                while *guard != 10 {
+                    let _ = cv.wait(&mut guard);
+                }
+            }
+            cv.notify_one();
+            cv.notify_all();
+            cv.free_waiters();
+        }
+
+        Ok(RustSync)
+    }
+}
+
+impl Drop for RustSync {
+    fn drop(&mut self) {
+        pr_info!("Rust synchronisation primitives sample (exit)\n");
+    }
+}
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 23/25] MAINTAINERS: Rust
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (18 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 22/25] samples: add Rust examples Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-05-23  2:01 ` [PATCH v7 24/25] [RFC] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda
  2022-07-16 12:42 ` [PATCH v7 00/25] Rust support Conor Dooley
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Kees Cook, Alex Gaynor, Wedson Almeida Filho

Miguel, Alex and Wedson will be maintaining the Rust support.

Reviewed-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 MAINTAINERS | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index f468864fd268..b2c41b2ed14e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17149,6 +17149,21 @@ L:	linux-rdma@vger.kernel.org
 S:	Maintained
 F:	drivers/infiniband/ulp/rtrs/
 
+RUST
+M:	Miguel Ojeda <ojeda@kernel.org>
+M:	Alex Gaynor <alex.gaynor@gmail.com>
+M:	Wedson Almeida Filho <wedsonaf@google.com>
+L:	rust-for-linux@vger.kernel.org
+S:	Supported
+W:	https://github.com/Rust-for-Linux/linux
+B:	https://github.com/Rust-for-Linux/linux/issues
+T:	git https://github.com/Rust-for-Linux/linux.git rust-next
+F:	Documentation/rust/
+F:	rust/
+F:	samples/rust/
+F:	scripts/*rust*
+K:	\b(?i:rust)\b
+
 RXRPC SOCKETS (AF_RXRPC)
 M:	David Howells <dhowells@redhat.com>
 M:	Marc Dionne <marc.dionne@auristor.com>
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* [PATCH v7 24/25] [RFC] drivers: gpio: PrimeCell PL061 in Rust
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (19 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 23/25] MAINTAINERS: Rust Miguel Ojeda
@ 2022-05-23  2:01 ` Miguel Ojeda
  2022-07-16 12:42 ` [PATCH v7 00/25] Rust support Conor Dooley
  21 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-23  2:01 UTC (permalink / raw)
  To: Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Miguel Ojeda,
	Wedson Almeida Filho, Linus Walleij, Bartosz Golaszewski,
	linux-gpio

From: Wedson Almeida Filho <wedsonaf@google.com>

A port to Rust of the PrimeCell PL061 GPIO driver.

This module is a work in progress and will be sent for review later
on, as well as separately from the Rust support.

However, it is included to show how an actual working module
written in Rust may look like.

Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 drivers/gpio/Kconfig            |   8 +
 drivers/gpio/Makefile           |   1 +
 drivers/gpio/gpio_pl061_rust.rs | 370 ++++++++++++++++++++++++++++++++
 3 files changed, 379 insertions(+)
 create mode 100644 drivers/gpio/gpio_pl061_rust.rs

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 45764ec3b2eb..ad99b96f6d79 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -481,6 +481,14 @@ config GPIO_PL061
 	help
 	  Say yes here to support the PrimeCell PL061 GPIO device.
 
+config GPIO_PL061_RUST
+	tristate "PrimeCell PL061 GPIO support written in Rust"
+	depends on ARM_AMBA && RUST
+	select IRQ_DOMAIN
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support the PrimeCell PL061 GPIO device
+
 config GPIO_PMIC_EIC_SPRD
 	tristate "Spreadtrum PMIC EIC support"
 	depends on MFD_SC27XX_PMIC || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 14352f6dfe8e..30141fec12be 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -118,6 +118,7 @@ obj-$(CONFIG_GPIO_PCIE_IDIO_24)		+= gpio-pcie-idio-24.o
 obj-$(CONFIG_GPIO_PCI_IDIO_16)		+= gpio-pci-idio-16.o
 obj-$(CONFIG_GPIO_PISOSR)		+= gpio-pisosr.o
 obj-$(CONFIG_GPIO_PL061)		+= gpio-pl061.o
+obj-$(CONFIG_GPIO_PL061_RUST)		+= gpio_pl061_rust.o
 obj-$(CONFIG_GPIO_PMIC_EIC_SPRD)	+= gpio-pmic-eic-sprd.o
 obj-$(CONFIG_GPIO_PXA)			+= gpio-pxa.o
 obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)	+= gpio-raspberrypi-exp.o
diff --git a/drivers/gpio/gpio_pl061_rust.rs b/drivers/gpio/gpio_pl061_rust.rs
new file mode 100644
index 000000000000..908914080442
--- /dev/null
+++ b/drivers/gpio/gpio_pl061_rust.rs
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Driver for the ARM PrimeCell(tm) General Purpose Input/Output (PL061).
+//!
+//! Based on the C driver written by Baruch Siach <baruch@tkos.co.il>.
+
+use kernel::{
+    amba, bit, bits_iter, define_amba_id_table, device, gpio,
+    io_mem::IoMem,
+    irq::{self, ExtraResult, IrqData, LockedIrqData},
+    power,
+    prelude::*,
+    sync::{RawSpinLock, Ref, RefBorrow},
+};
+
+const GPIODIR: usize = 0x400;
+const GPIOIS: usize = 0x404;
+const GPIOIBE: usize = 0x408;
+const GPIOIEV: usize = 0x40C;
+const GPIOIE: usize = 0x410;
+const GPIOMIS: usize = 0x418;
+const GPIOIC: usize = 0x41C;
+const GPIO_SIZE: usize = 0x1000;
+
+const PL061_GPIO_NR: u16 = 8;
+
+#[derive(Default)]
+struct ContextSaveRegs {
+    gpio_data: u8,
+    gpio_dir: u8,
+    gpio_is: u8,
+    gpio_ibe: u8,
+    gpio_iev: u8,
+    gpio_ie: u8,
+}
+
+#[derive(Default)]
+struct PL061DataInner {
+    csave_regs: ContextSaveRegs,
+}
+
+struct PL061Data {
+    dev: device::Device,
+    inner: RawSpinLock<PL061DataInner>,
+}
+
+struct PL061Resources {
+    base: IoMem<GPIO_SIZE>,
+    parent_irq: u32,
+}
+
+type PL061Registrations = gpio::RegistrationWithIrqChip<PL061Device>;
+
+type DeviceData = device::Data<PL061Registrations, PL061Resources, PL061Data>;
+
+struct PL061Device;
+
+impl gpio::Chip for PL061Device {
+    type Data = Ref<DeviceData>;
+
+    kernel::declare_gpio_chip_operations!(
+        get_direction,
+        direction_input,
+        direction_output,
+        get,
+        set
+    );
+
+    fn get_direction(data: RefBorrow<'_, DeviceData>, offset: u32) -> Result<gpio::LineDirection> {
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        Ok(if pl061.base.readb(GPIODIR) & bit(offset) != 0 {
+            gpio::LineDirection::Out
+        } else {
+            gpio::LineDirection::In
+        })
+    }
+
+    fn direction_input(data: RefBorrow<'_, DeviceData>, offset: u32) -> Result {
+        let _guard = data.inner.lock_irqdisable();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        let mut gpiodir = pl061.base.readb(GPIODIR);
+        gpiodir &= !bit(offset);
+        pl061.base.writeb(gpiodir, GPIODIR);
+        Ok(())
+    }
+
+    fn direction_output(data: RefBorrow<'_, DeviceData>, offset: u32, value: bool) -> Result {
+        let woffset = bit(offset + 2).into();
+        let _guard = data.inner.lock_irqdisable();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        pl061.base.try_writeb((value as u8) << offset, woffset)?;
+        let mut gpiodir = pl061.base.readb(GPIODIR);
+        gpiodir |= bit(offset);
+        pl061.base.writeb(gpiodir, GPIODIR);
+
+        // gpio value is set again, because pl061 doesn't allow to set value of a gpio pin before
+        // configuring it in OUT mode.
+        pl061.base.try_writeb((value as u8) << offset, woffset)?;
+        Ok(())
+    }
+
+    fn get(data: RefBorrow<'_, DeviceData>, offset: u32) -> Result<bool> {
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        Ok(pl061.base.try_readb(bit(offset + 2).into())? != 0)
+    }
+
+    fn set(data: RefBorrow<'_, DeviceData>, offset: u32, value: bool) {
+        if let Some(pl061) = data.resources() {
+            let woffset = bit(offset + 2).into();
+            let _ = pl061.base.try_writeb((value as u8) << offset, woffset);
+        }
+    }
+}
+
+impl gpio::ChipWithIrqChip for PL061Device {
+    fn handle_irq_flow(
+        data: RefBorrow<'_, DeviceData>,
+        desc: &irq::Descriptor,
+        domain: &irq::Domain,
+    ) {
+        let chained = desc.enter_chained();
+
+        if let Some(pl061) = data.resources() {
+            let pending = pl061.base.readb(GPIOMIS);
+            for offset in bits_iter(pending) {
+                domain.generic_handle_chained(offset, &chained);
+            }
+        }
+    }
+}
+
+impl irq::Chip for PL061Device {
+    type Data = Ref<DeviceData>;
+
+    kernel::declare_irq_chip_operations!(set_type, set_wake);
+
+    fn set_type(
+        data: RefBorrow<'_, DeviceData>,
+        irq_data: &mut LockedIrqData,
+        trigger: u32,
+    ) -> Result<ExtraResult> {
+        let offset = irq_data.hwirq();
+        let bit = bit(offset);
+
+        if offset >= PL061_GPIO_NR.into() {
+            return Err(EINVAL);
+        }
+
+        if trigger & (irq::Type::LEVEL_HIGH | irq::Type::LEVEL_LOW) != 0
+            && trigger & (irq::Type::EDGE_RISING | irq::Type::EDGE_FALLING) != 0
+        {
+            dev_err!(
+                data.dev,
+                "trying to configure line {} for both level and edge detection, choose one!\n",
+                offset
+            );
+            return Err(EINVAL);
+        }
+
+        let _guard = data.inner.lock_irqdisable();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+
+        let mut gpioiev = pl061.base.readb(GPIOIEV);
+        let mut gpiois = pl061.base.readb(GPIOIS);
+        let mut gpioibe = pl061.base.readb(GPIOIBE);
+
+        if trigger & (irq::Type::LEVEL_HIGH | irq::Type::LEVEL_LOW) != 0 {
+            let polarity = trigger & irq::Type::LEVEL_HIGH != 0;
+
+            // Disable edge detection.
+            gpioibe &= !bit;
+            // Enable level detection.
+            gpiois |= bit;
+            // Select polarity.
+            if polarity {
+                gpioiev |= bit;
+            } else {
+                gpioiev &= !bit;
+            }
+            irq_data.set_level_handler();
+            dev_dbg!(
+                data.dev,
+                "line {}: IRQ on {} level\n",
+                offset,
+                if polarity { "HIGH" } else { "LOW" }
+            );
+        } else if (trigger & irq::Type::EDGE_BOTH) == irq::Type::EDGE_BOTH {
+            // Disable level detection.
+            gpiois &= !bit;
+            // Select both edges, settings this makes GPIOEV be ignored.
+            gpioibe |= bit;
+            irq_data.set_edge_handler();
+            dev_dbg!(data.dev, "line {}: IRQ on both edges\n", offset);
+        } else if trigger & (irq::Type::EDGE_RISING | irq::Type::EDGE_FALLING) != 0 {
+            let rising = trigger & irq::Type::EDGE_RISING != 0;
+
+            // Disable level detection.
+            gpiois &= !bit;
+            // Clear detection on both edges.
+            gpioibe &= !bit;
+            // Select edge.
+            if rising {
+                gpioiev |= bit;
+            } else {
+                gpioiev &= !bit;
+            }
+            irq_data.set_edge_handler();
+            dev_dbg!(
+                data.dev,
+                "line {}: IRQ on {} edge\n",
+                offset,
+                if rising { "RISING" } else { "FALLING}" }
+            );
+        } else {
+            // No trigger: disable everything.
+            gpiois &= !bit;
+            gpioibe &= !bit;
+            gpioiev &= !bit;
+            irq_data.set_bad_handler();
+            dev_warn!(data.dev, "no trigger selected for line {}\n", offset);
+        }
+
+        pl061.base.writeb(gpiois, GPIOIS);
+        pl061.base.writeb(gpioibe, GPIOIBE);
+        pl061.base.writeb(gpioiev, GPIOIEV);
+
+        Ok(ExtraResult::None)
+    }
+
+    fn mask(data: RefBorrow<'_, DeviceData>, irq_data: &IrqData) {
+        let mask = bit(irq_data.hwirq() % irq::HwNumber::from(PL061_GPIO_NR));
+        let _guard = data.inner.lock();
+        if let Some(pl061) = data.resources() {
+            let gpioie = pl061.base.readb(GPIOIE) & !mask;
+            pl061.base.writeb(gpioie, GPIOIE);
+        }
+    }
+
+    fn unmask(data: RefBorrow<'_, DeviceData>, irq_data: &IrqData) {
+        let mask = bit(irq_data.hwirq() % irq::HwNumber::from(PL061_GPIO_NR));
+        let _guard = data.inner.lock();
+        if let Some(pl061) = data.resources() {
+            let gpioie = pl061.base.readb(GPIOIE) | mask;
+            pl061.base.writeb(gpioie, GPIOIE);
+        }
+    }
+
+    // This gets called from the edge IRQ handler to ACK the edge IRQ in the GPIOIC
+    // (interrupt-clear) register. For level IRQs this is not needed: these go away when the level
+    // signal goes away.
+    fn ack(data: RefBorrow<'_, DeviceData>, irq_data: &IrqData) {
+        let mask = bit(irq_data.hwirq() % irq::HwNumber::from(PL061_GPIO_NR));
+        let _guard = data.inner.lock();
+        if let Some(pl061) = data.resources() {
+            pl061.base.writeb(mask.into(), GPIOIC);
+        }
+    }
+
+    fn set_wake(data: RefBorrow<'_, DeviceData>, _irq_data: &IrqData, on: bool) -> Result {
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        irq::set_wake(pl061.parent_irq, on)
+    }
+}
+
+impl amba::Driver for PL061Device {
+    type Data = Ref<DeviceData>;
+    type PowerOps = Self;
+
+    define_amba_id_table! {(), [
+        ({id: 0x00041061, mask: 0x000fffff}, None),
+    ]}
+
+    fn probe(dev: &mut amba::Device, _data: Option<&Self::IdInfo>) -> Result<Ref<DeviceData>> {
+        let res = dev.take_resource().ok_or(ENXIO)?;
+        let irq = dev.irq(0).ok_or(ENXIO)?;
+
+        let mut data = kernel::new_device_data!(
+            gpio::RegistrationWithIrqChip::new(),
+            PL061Resources {
+                // SAFETY: This device doesn't support DMA.
+                base: unsafe { IoMem::try_new(res)? },
+                parent_irq: irq,
+            },
+            PL061Data {
+                dev: device::Device::from_dev(dev),
+                // SAFETY: We call `rawspinlock_init` below.
+                inner: unsafe { RawSpinLock::new(PL061DataInner::default()) },
+            },
+            "PL061::Registrations"
+        )?;
+
+        // SAFETY: General part of the data is pinned when `data` is.
+        let gen_inner = unsafe { data.as_mut().map_unchecked_mut(|d| &mut (**d).inner) };
+        kernel::rawspinlock_init!(gen_inner, "PL061Data::inner");
+
+        let data = Ref::<DeviceData>::from(data);
+
+        data.resources().ok_or(ENXIO)?.base.writeb(0, GPIOIE); // disable irqs
+
+        data.registrations()
+            .ok_or(ENXIO)?
+            .as_pinned_mut()
+            .register::<Self>(PL061_GPIO_NR, None, dev, data.clone(), irq)?;
+
+        dev_info!(data.dev, "PL061 GPIO chip registered\n");
+
+        Ok(data)
+    }
+}
+
+impl power::Operations for PL061Device {
+    type Data = Ref<DeviceData>;
+
+    fn suspend(data: RefBorrow<'_, DeviceData>) -> Result {
+        let mut inner = data.inner.lock();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        inner.csave_regs.gpio_data = 0;
+        inner.csave_regs.gpio_dir = pl061.base.readb(GPIODIR);
+        inner.csave_regs.gpio_is = pl061.base.readb(GPIOIS);
+        inner.csave_regs.gpio_ibe = pl061.base.readb(GPIOIBE);
+        inner.csave_regs.gpio_iev = pl061.base.readb(GPIOIEV);
+        inner.csave_regs.gpio_ie = pl061.base.readb(GPIOIE);
+
+        for offset in 0..PL061_GPIO_NR {
+            if inner.csave_regs.gpio_dir & bit(offset) != 0 {
+                if let Ok(v) = <Self as gpio::Chip>::get(data, offset.into()) {
+                    inner.csave_regs.gpio_data |= (v as u8) << offset;
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    fn resume(data: RefBorrow<'_, DeviceData>) -> Result {
+        let inner = data.inner.lock();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+
+        for offset in 0..PL061_GPIO_NR {
+            if inner.csave_regs.gpio_dir & bit(offset) != 0 {
+                let value = inner.csave_regs.gpio_data & bit(offset) != 0;
+                let _ = <Self as gpio::Chip>::direction_output(data, offset.into(), value);
+            } else {
+                let _ = <Self as gpio::Chip>::direction_input(data, offset.into());
+            }
+        }
+
+        pl061.base.writeb(inner.csave_regs.gpio_is, GPIOIS);
+        pl061.base.writeb(inner.csave_regs.gpio_ibe, GPIOIBE);
+        pl061.base.writeb(inner.csave_regs.gpio_iev, GPIOIEV);
+        pl061.base.writeb(inner.csave_regs.gpio_ie, GPIOIE);
+
+        Ok(())
+    }
+
+    fn freeze(data: RefBorrow<'_, DeviceData>) -> Result {
+        Self::suspend(data)
+    }
+
+    fn restore(data: RefBorrow<'_, DeviceData>) -> Result {
+        Self::resume(data)
+    }
+}
+
+module_amba_driver! {
+    type: PL061Device,
+    name: b"pl061_gpio",
+    author: b"Wedson Almeida Filho",
+    license: b"GPL",
+}
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side
  2022-05-23  2:01 ` [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side Miguel Ojeda
@ 2022-05-23  2:17   ` Joe Perches
  2022-05-24 16:35     ` Miguel Ojeda
  0 siblings, 1 reply; 50+ messages in thread
From: Joe Perches @ 2022-05-23  2:17 UTC (permalink / raw)
  To: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman
  Cc: rust-for-linux, linux-kernel, Jarkko Sakkinen, Kees Cook,
	Alex Gaynor, Wedson Almeida Filho, Andy Whitcroft, Dwaipayan Ray,
	Lukas Bulwahn

On Mon, 2022-05-23 at 04:01 +0200, Miguel Ojeda wrote:
> The `%pA` format specifier is only intended to be used from Rust.
> 
> `checkpatch.pl` already gives a warning for invalid specificers:
> 
>     WARNING: Invalid vsprintf pointer extension '%pA'
> 
> With this change, we introduce an error message with further
> explanation:
> 
>     ERROR: '%pA' is only intended to be used from Rust code
> 
> Suggested-by: Kees Cook <keescook@chromium.org>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

How many developers are required for a trivial patch?

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -6784,6 +6784,10 @@ sub process {
>  					my $stat_real = get_stat_real($linenr, $lc);
>  					my $ext_type = "Invalid";
>  					my $use = "";
> +					if ($bad_specifier =~ /pA/) {
> +						ERROR("VSPRINTF_RUST",
> +							"'\%pA' is only intended to be used from Rust code\n" . "$here\n$stat_real\n");
> +					}
>  					if ($bad_specifier =~ /p[Ff]/) {

and this should now use elsif

>  						$use = " - use %pS instead";
>  						$use =~ s/pS/ps/ if ($bad_specifier =~ /pf/);



^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 04/25] kunit: take `kunit_assert` as `const`
  2022-05-23  2:01 ` [PATCH v7 04/25] kunit: take `kunit_assert` as `const` Miguel Ojeda
@ 2022-05-23 17:15   ` Daniel Latypov
  2022-05-23 18:14     ` Shuah Khan
  0 siblings, 1 reply; 50+ messages in thread
From: Daniel Latypov @ 2022-05-23 17:15 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Jarkko Sakkinen, Brendan Higgins, linux-kselftest, kunit-dev

On Sun, May 22, 2022 at 7:03 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> The `kunit_do_failed_assertion` function passes its
> `struct kunit_assert` argument to `kunit_fail`. This one,
> in turn, calls its `format` field passing the assert again
> as a `const` pointer.
>
> Therefore, the whole chain may be made `const`.
>
> Reviewed-by: Daniel Latypov <dlatypov@google.com>
> Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> This is a prerequisite patch, independently submitted at:
>
>     https://lore.kernel.org/lkml/20220502093625.GA23225@kernel.org/

FYI, we'd asked Shuah to pick this patch up in her "kunit" branch.
It's applied here:
https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/commit/?h=kunit&id=7466886b400b1904ce30fa311904849e314a2cf4

It had previously seemed unclear if this series could make it for the
5.19 merge window (but it now looks like there's interest in trying it
out early on).

Daniel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 04/25] kunit: take `kunit_assert` as `const`
  2022-05-23 17:15   ` Daniel Latypov
@ 2022-05-23 18:14     ` Shuah Khan
  2022-05-24 12:37       ` Miguel Ojeda
  0 siblings, 1 reply; 50+ messages in thread
From: Shuah Khan @ 2022-05-23 18:14 UTC (permalink / raw)
  To: Daniel Latypov, Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Jarkko Sakkinen, Brendan Higgins, linux-kselftest, kunit-dev,
	Shuah Khan

On 5/23/22 11:15 AM, Daniel Latypov wrote:
> On Sun, May 22, 2022 at 7:03 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>>
>> The `kunit_do_failed_assertion` function passes its
>> `struct kunit_assert` argument to `kunit_fail`. This one,
>> in turn, calls its `format` field passing the assert again
>> as a `const` pointer.
>>
>> Therefore, the whole chain may be made `const`.
>>
>> Reviewed-by: Daniel Latypov <dlatypov@google.com>
>> Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
>> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
>> ---
>> This is a prerequisite patch, independently submitted at:
>>
>>      https://lore.kernel.org/lkml/20220502093625.GA23225@kernel.org/
> 
> FYI, we'd asked Shuah to pick this patch up in her "kunit" branch.
> It's applied here:
> https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/commit/?h=kunit&id=7466886b400b1904ce30fa311904849e314a2cf4
> 
> It had previously seemed unclear if this series could make it for the
> 5.19 merge window (but it now looks like there's interest in trying it
> out early on).
> 
> Daniel
> 

I am just about send pull request with this patch included.

thanks,
-- Shuah

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 06/25] rust: add `compiler_builtins` crate
  2022-05-23  2:01 ` [PATCH v7 06/25] rust: add `compiler_builtins` crate Miguel Ojeda
@ 2022-05-23 18:37   ` Nick Desaulniers
  2022-05-23 23:41     ` Gary Guo
  2022-05-24 12:29     ` Miguel Ojeda
  0 siblings, 2 replies; 50+ messages in thread
From: Nick Desaulniers @ 2022-05-23 18:37 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Jarkko Sakkinen, Alex Gaynor, Wedson Almeida Filho,
	Sven Van Asbroeck, Gary Guo

On Sun, May 22, 2022 at 7:03 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Rust provides `compiler_builtins` as a port of LLVM's `compiler-rt`.
> Since we do not need the vast majority of them, we avoid the
> dependency by providing our own crate.
>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
> Co-developed-by: Gary Guo <gary@garyguo.net>
> Signed-off-by: Gary Guo <gary@garyguo.net>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>  rust/compiler_builtins.rs | 57 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 rust/compiler_builtins.rs
>
> diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
> new file mode 100644
> index 000000000000..80ca4c0dcd24
> --- /dev/null
> +++ b/rust/compiler_builtins.rs
> @@ -0,0 +1,57 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! Our own `compiler_builtins`.
> +//!
> +//! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`].
> +//! Since we do not need the vast majority of them, we avoid the dependency
> +//! by providing this file.
> +//!
> +//! At the moment, some builtins are required that should not be. For instance,
> +//! [`core`] has 128-bit integers functionality which we should not be compiling
> +//! in. We will work with upstream [`core`] to provide feature flags to disable
> +//! the parts we do not need. For the moment, we define them to [`panic!`] at

^ Any progress on this? Got any links to any feature requests or bug reports.

Also, I'm not sure my concern about explicit build failures for C code
was ever addressed?  We have a constant problem with `long long`
division on ARCH=arm32 and ARCH=i386 in C code.
https://lore.kernel.org/lkml/CAKwvOdk+A2PBdjSFVUhj4xyCGCKujtej1uPgywQgrKPiK2ksPw@mail.gmail.com/

> +//! runtime for simplicity to catch mistakes, instead of performing surgery
> +//! on `core.o`.
> +//!
> +//! In any case, all these symbols are weakened to ensure we do not override
> +//! those that may be provided by the rest of the kernel.
> +//!
> +//! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins
> +//! [`compiler-rt`]: https://compiler-rt.llvm.org/
> +
> +#![feature(compiler_builtins)]
> +#![compiler_builtins]
> +#![no_builtins]
> +#![no_std]
> +
> +macro_rules! define_panicking_intrinsics(
> +    ($reason: tt, { $($ident: ident, )* }) => {
> +        $(
> +            #[doc(hidden)]
> +            #[no_mangle]
> +            pub extern "C" fn $ident() {
> +                panic!($reason);
> +            }
> +        )*
> +    }
> +);
> +
> +define_panicking_intrinsics!("`i128` should not be used", {
> +    __ashrti3,
> +    __muloti4,
> +    __multi3,
> +});
> +
> +define_panicking_intrinsics!("`u128` should not be used", {
> +    __ashlti3,
> +    __lshrti3,
> +    __udivmodti4,
> +    __udivti3,
> +    __umodti3,
> +});
> +
> +#[cfg(target_arch = "arm")]
> +define_panicking_intrinsics!("`u64` division/modulo should not be used", {
> +    __aeabi_uldivmod,
> +    __mulodi4,
> +});
> --
> 2.36.1
>


-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 21/25] Kbuild: add Rust support
  2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
@ 2022-05-23 18:44   ` Nick Desaulniers
  2022-05-24 15:12     ` Miguel Ojeda
  2022-05-25 22:25   ` Nick Desaulniers
  2022-07-16  8:21   ` Masahiro Yamada
  2 siblings, 1 reply; 50+ messages in thread
From: Nick Desaulniers @ 2022-05-23 18:44 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Jarkko Sakkinen, Alex Gaynor, Finn Behrens, Adam Bratschi-Kaye,
	Wedson Almeida Filho, Michael Ellerman, Sven Van Asbroeck,
	Gary Guo, Boris-Chengbiao Zhou, Boqun Feng, Douglas Su,
	Dariusz Sosnowski, Antonio Terceiro, Daniel Xu, Miguel Cano,
	David Gow, Masahiro Yamada, Michal Marek, Russell King,
	Catalin Marinas, Will Deacon, Benjamin Herrenschmidt,
	Paul Mackerras, Paul Walmsley, Palmer Dabbelt, Albert Ou,
	Richard Weinberger, Anton Ivanov, Johannes Berg, Thomas Gleixner,
	Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
	linux-kbuild, linux-arm-kernel, linuxppc-dev, linux-riscv,
	linux-um

> +choice
> +       prompt "Optimization level"
> +       default RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C
> +       depends on RUST
> +       help
> +         Controls rustc's `-Copt-level` codegen option.
> +
> +         This flag controls the optimization level.
> +
> +         If unsure, say "Similar as chosen for C".
> +
> +config RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C
> +       bool "Similar as chosen for C"
> +       help
> +         This choice will pick a similar optimization level as chosen in
> +         the "Compiler optimization level" for C:
> +
> +             -O2 is currently mapped to -Copt-level=2
> +             -O3 is currently mapped to -Copt-level=3
> +             -Os is currently mapped to -Copt-level=s
> +
> +         The mapping may change over time to follow the intended semantics
> +         of the choice for C as sensibly as possible.
> +
> +         This is the default.
> +
> +config RUST_OPT_LEVEL_0
> +       bool "No optimizations (-Copt-level=0)"
> +       help
> +         Not recommended for most purposes. It may come in handy for debugging
> +         suspected optimizer bugs, unexpected undefined behavior, etc.
> +
> +         Note that this level will *not* enable debug assertions nor overflow
> +         checks on its own (like it happens when interacting with rustc
> +         directly). Use the corresponding configuration options to control
> +         that instead, orthogonally.
> +
> +         Note this level may cause excessive stack usage, which can lead to stack
> +         overflow and subsequent crashes.
> +
> +config RUST_OPT_LEVEL_1
> +       bool "Basic optimizations (-Copt-level=1)"
> +       help
> +         Useful for debugging without getting too lost, but without
> +         the overhead and boilerplate of no optimizations at all.
> +
> +         Note this level may cause excessive stack usage, which can lead to stack
> +         overflow and subsequent crashes.
> +
> +config RUST_OPT_LEVEL_2
> +       bool "Some optimizations (-Copt-level=2)"
> +       help
> +         The sensible choice in most cases.
> +
> +config RUST_OPT_LEVEL_3
> +       bool "All optimizations (-Copt-level=3)"
> +       help
> +         Yet more performance (hopefully).
> +
> +config RUST_OPT_LEVEL_S
> +       bool "Optimize for size (-Copt-level=s)"
> +       help
> +         Smaller kernel, ideally without too much performance loss.
> +
> +config RUST_OPT_LEVEL_Z
> +       bool "Optimize for size, no loop vectorization (-Copt-level=z)"
> +       help
> +         Like the previous level, but also turn off loop vectorization.

I'm super not into having the rust optimization level differ from the
C optimization level.  This is just someone having too much fun
wrapping every compiler flag in a kbuild option.  Either folks wan't
smaller size or more optimizations. Allowing for RUST_OPT_LEVEL_S and
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE or RUST_OPT_LEVEL_3 and
CONFIG_CC_OPTIMIZE_FOR_SIZE is just wacky nonsense that's going to
make randconfig bug reports more confusing to tease out.
-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size
  2022-05-23  2:01 ` [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size Miguel Ojeda
@ 2022-05-23 19:45   ` Jarkko Sakkinen
  2022-05-23 19:55     ` Jarkko Sakkinen
  2022-05-24 16:21     ` Miguel Ojeda
  0 siblings, 2 replies; 50+ messages in thread
From: Jarkko Sakkinen @ 2022-05-23 19:45 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Boqun Feng, Kees Cook

On Mon, May 23, 2022 at 04:01:14AM +0200, Miguel Ojeda wrote:
> From: Boqun Feng <boqun.feng@gmail.com>
> 
> This makes it easier to update the size later on.
> 

This does not really conform to [1].

E.g.

"Declare KSY_NAME_LEN, which describes the maximum length for a kernel
symbol read by kallsyms from the input.  In read_symbol(), define the 
buffer to be of length "KSY_NAME_LEN + 1", which includes the terminator
character."

would be better.

> Furthermore, a static assert is added to ensure both are updated
> when that happens. The relationship used is one that keeps the new
> size (512+1) close to the original buffer size (500).

You must split this then into two patches:

1. A patch that re-defines the length with KSYM_NAME_LEN, i.e.
   #define KSYM_NAME_LEN 499
2. A patch which increases the size and reasoning for that.

Right now bundles two separate changes, which does not conform to [2].

BR, Jarkko

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size
  2022-05-23 19:45   ` Jarkko Sakkinen
@ 2022-05-23 19:55     ` Jarkko Sakkinen
  2022-05-24 16:21     ` Miguel Ojeda
  1 sibling, 0 replies; 50+ messages in thread
From: Jarkko Sakkinen @ 2022-05-23 19:55 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Boqun Feng, Kees Cook

On Mon, May 23, 2022 at 10:45:11PM +0300, Jarkko Sakkinen wrote:
> On Mon, May 23, 2022 at 04:01:14AM +0200, Miguel Ojeda wrote:
> > From: Boqun Feng <boqun.feng@gmail.com>
> > 
> > This makes it easier to update the size later on.
> > 
> 
> This does not really conform to [1].
> 
> E.g.
> 
> "Declare KSY_NAME_LEN, which describes the maximum length for a kernel
> symbol read by kallsyms from the input.  In read_symbol(), define the 
> buffer to be of length "KSY_NAME_LEN + 1", which includes the terminator
> character."
> 
> would be better.
> 
> > Furthermore, a static assert is added to ensure both are updated
> > when that happens. The relationship used is one that keeps the new
> > size (512+1) close to the original buffer size (500).
> 
> You must split this then into two patches:
> 
> 1. A patch that re-defines the length with KSYM_NAME_LEN, i.e.
>    #define KSYM_NAME_LEN 499
> 2. A patch which increases the size and reasoning for that.
> 
> Right now bundles two separate changes, which does not conform to [2].
> 
> BR, Jarkko

The URL's:

[1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-changes
[2] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#separate-your-changes

BR, Jarkko

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 02/25] kallsyms: support "big" kernel symbols
  2022-05-23  2:01 ` [PATCH v7 02/25] kallsyms: support "big" kernel symbols Miguel Ojeda
@ 2022-05-23 20:30   ` Jarkko Sakkinen
  0 siblings, 0 replies; 50+ messages in thread
From: Jarkko Sakkinen @ 2022-05-23 20:30 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Kees Cook, Alex Gaynor, Wedson Almeida Filho, Gary Guo,
	Boqun Feng, Matthew Wilcox

On Mon, May 23, 2022 at 04:01:15AM +0200, Miguel Ojeda wrote:
> Rust symbols can become quite long due to namespacing introduced
> by modules, types, traits, generics, etc.
> 
> Increasing to 255 is not enough in some cases, and therefore
> we need to introduce longer lengths to the symbol table.

s/we need to//

> 
> In order to avoid increasing all lengths to 2 bytes (since most
> of them are small, including many Rust ones), we use ULEB128 to

s/we//

> keep smaller symbols in 1 byte, with the rest in 2 bytes.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Co-developed-by: Gary Guo <gary@garyguo.net>
> Signed-off-by: Gary Guo <gary@garyguo.net>
> Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Co-developed-by: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> This is a prerequisite patch, independently submitted at:
> 
>     https://lore.kernel.org/lkml/20220506203443.24721-3-ojeda@kernel.org/
> 
>  kernel/kallsyms.c  | 26 ++++++++++++++++++++++----
>  scripts/kallsyms.c | 29 ++++++++++++++++++++++++++---
>  2 files changed, 48 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
> index 79f2eb617a62..e8d2262ef2d2 100644
> --- a/kernel/kallsyms.c
> +++ b/kernel/kallsyms.c
> @@ -69,12 +69,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off,
>  	data = &kallsyms_names[off];
>  	len = *data;
>  	data++;
> +	off++;
> +
> +	/* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
> +	if ((len & 0x80) != 0) {
> +		len = (len & 0x7F) | (*data << 7);
> +		data++;
> +		off++;
> +	}
>  
>  	/*
>  	 * Update the offset to return the offset for the next symbol on
>  	 * the compressed stream.
>  	 */
> -	off += len + 1;
> +	off += len;
>  
>  	/*
>  	 * For every byte on the compressed symbol data, copy the table
> @@ -127,7 +135,7 @@ static char kallsyms_get_symbol_type(unsigned int off)
>  static unsigned int get_symbol_offset(unsigned long pos)
>  {
>  	const u8 *name;
> -	int i;
> +	int i, len;
>  
>  	/*
>  	 * Use the closest marker we have. We have markers every 256 positions,
> @@ -141,8 +149,18 @@ static unsigned int get_symbol_offset(unsigned long pos)
>  	 * so we just need to add the len to the current pointer for every
>  	 * symbol we wish to skip.
>  	 */
> -	for (i = 0; i < (pos & 0xFF); i++)
> -		name = name + (*name) + 1;
> +	for (i = 0; i < (pos & 0xFF); i++) {
> +		len = *name;
> +
> +		/*
> +		 * If MSB is 1, it is a "big" symbol, so we need to look into
> +		 * the next byte (and skip it, too).
> +		 */
> +		if ((len & 0x80) != 0)
> +			len = ((len & 0x7F) | (name[1] << 7)) + 1;
> +
> +		name = name + len + 1;
> +	}
>  
>  	return name - kallsyms_names;
>  }
> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index 82d6508bdf29..7e99799aa7b9 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -480,12 +480,35 @@ static void write_src(void)
>  		if ((i & 0xFF) == 0)
>  			markers[i >> 8] = off;
>  
> -		printf("\t.byte 0x%02x", table[i]->len);
> +		/* There cannot be any symbol of length zero. */
> +		if (table[i]->len == 0) {
> +			fprintf(stderr, "kallsyms failure: "
> +				"unexpected zero symbol length\n");
> +			exit(EXIT_FAILURE);
> +		}
> +
> +		/* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
> +		if (table[i]->len > 0x3FFF) {
> +			fprintf(stderr, "kallsyms failure: "
> +				"unexpected huge symbol length\n");
> +			exit(EXIT_FAILURE);
> +		}
> +
> +		/* Encode length with ULEB128. */
> +		if (table[i]->len <= 0x7F) {
> +			/* Most symbols use a single byte for the length. */
> +			printf("\t.byte 0x%02x", table[i]->len);
> +			off += table[i]->len + 1;
> +		} else {
> +			/* "Big" symbols use two bytes. */
> +			printf("\t.byte 0x%02x, 0x%02x",
> +				(table[i]->len & 0x7F) | 0x80,
> +				(table[i]->len >> 7) & 0x7F);
> +			off += table[i]->len + 2;
> +		}
>  		for (k = 0; k < table[i]->len; k++)
>  			printf(", 0x%02x", table[i]->sym[k]);
>  		printf("\n");
> -
> -		off += table[i]->len + 1;
>  	}
>  	printf("\n");
>  
> -- 
> 2.36.1
> 

BR, Jarkko

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512
  2022-05-23  2:01 ` [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
@ 2022-05-23 20:31   ` Jarkko Sakkinen
  2022-05-24 18:07     ` Miguel Ojeda
  0 siblings, 1 reply; 50+ messages in thread
From: Jarkko Sakkinen @ 2022-05-23 20:31 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Kees Cook, Petr Mladek, Alex Gaynor, Wedson Almeida Filho,
	Gary Guo, Boqun Feng, Josh Poimboeuf, Jiri Kosina,
	Miroslav Benes, Joe Lawrence, Peter Zijlstra, Ingo Molnar,
	Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
	Jiri Olsa, Namhyung Kim, live-patching, linux-perf-users

On Mon, May 23, 2022 at 04:01:16AM +0200, Miguel Ojeda wrote:
> Rust symbols can become quite long due to namespacing introduced
> by modules, types, traits, generics, etc. For instance,
> the following code:
> 
>     pub mod my_module {
>         pub struct MyType;
>         pub struct MyGenericType<T>(T);
> 
>         pub trait MyTrait {
>             fn my_method() -> u32;
>         }
> 
>         impl MyTrait for MyGenericType<MyType> {
>             fn my_method() -> u32 {
>                 42
>             }
>         }
>     }
> 
> generates a symbol of length 96 when using the upcoming v0 mangling scheme:
> 
>     _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method
> 
> At the moment, Rust symbols may reach up to 300 in length.
> Setting 512 as the maximum seems like a reasonable choice to
> keep some headroom.

There's no description what the patch does.

> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Co-developed-by: Gary Guo <gary@garyguo.net>
> Signed-off-by: Gary Guo <gary@garyguo.net>
> Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> This is a prerequisite patch, independently submitted at:
> 
>     https://lore.kernel.org/lkml/20220506203443.24721-4-ojeda@kernel.org/
> 
>  include/linux/kallsyms.h            | 2 +-
>  kernel/livepatch/core.c             | 4 ++--
>  scripts/kallsyms.c                  | 4 ++--
>  tools/include/linux/kallsyms.h      | 2 +-
>  tools/lib/perf/include/perf/event.h | 2 +-
>  tools/lib/symbol/kallsyms.h         | 2 +-
>  6 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
> index ce1bd2fbf23e..e5ad6e31697d 100644
> --- a/include/linux/kallsyms.h
> +++ b/include/linux/kallsyms.h
> @@ -15,7 +15,7 @@
>  
>  #include <asm/sections.h>
>  
> -#define KSYM_NAME_LEN 128
> +#define KSYM_NAME_LEN 512
>  #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \
>  			(KSYM_NAME_LEN - 1) + \
>  			2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index bc475e62279d..ec06ce59d728 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
>  	 * we use the smallest/strictest upper bound possible (56, based on
>  	 * the current definition of MODULE_NAME_LEN) to prevent overflows.
>  	 */
> -	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
> +	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
>  
>  	relas = (Elf_Rela *) relasec->sh_addr;
>  	/* For each rela in this klp relocation section */
> @@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
>  
>  		/* Format: .klp.sym.sym_objname.sym_name,sympos */
>  		cnt = sscanf(strtab + sym->st_name,
> -			     ".klp.sym.%55[^.].%127[^,],%lu",
> +			     ".klp.sym.%55[^.].%511[^,],%lu",
>  			     sym_objname, sym_name, &sympos);
>  		if (cnt != 3) {
>  			pr_err("symbol %s has an incorrectly formatted name\n",
> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index 7e99799aa7b9..275044b840dc 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -30,10 +30,10 @@
>  #define _stringify_1(x)	#x
>  #define _stringify(x)	_stringify_1(x)
>  
> -#define KSYM_NAME_LEN		128
> +#define KSYM_NAME_LEN		512
>  
>  /* A substantially bigger size than the current maximum. */
> -#define KSYM_NAME_LEN_BUFFER	512
> +#define KSYM_NAME_LEN_BUFFER	2048
>  _Static_assert(
>  	KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
>  	"Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
> diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
> index efb6c3f5f2a9..5a37ccbec54f 100644
> --- a/tools/include/linux/kallsyms.h
> +++ b/tools/include/linux/kallsyms.h
> @@ -6,7 +6,7 @@
>  #include <stdio.h>
>  #include <unistd.h>
>  
> -#define KSYM_NAME_LEN 128
> +#define KSYM_NAME_LEN 512
>  
>  struct module;
>  
> diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
> index e7758707cadd..116a80c31675 100644
> --- a/tools/lib/perf/include/perf/event.h
> +++ b/tools/lib/perf/include/perf/event.h
> @@ -95,7 +95,7 @@ struct perf_record_throttle {
>  };
>  
>  #ifndef KSYM_NAME_LEN
> -#define KSYM_NAME_LEN 256
> +#define KSYM_NAME_LEN 512
>  #endif
>  
>  struct perf_record_ksymbol {
> diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h
> index 72ab9870454b..542f9b059c3b 100644
> --- a/tools/lib/symbol/kallsyms.h
> +++ b/tools/lib/symbol/kallsyms.h
> @@ -7,7 +7,7 @@
>  #include <linux/types.h>
>  
>  #ifndef KSYM_NAME_LEN
> -#define KSYM_NAME_LEN 256
> +#define KSYM_NAME_LEN 512
>  #endif
>  
>  static inline u8 kallsyms2elf_binding(char type)
> -- 
> 2.36.1
> 

BR, Jarkko

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 06/25] rust: add `compiler_builtins` crate
  2022-05-23 18:37   ` Nick Desaulniers
@ 2022-05-23 23:41     ` Gary Guo
  2022-05-25 21:29       ` Nick Desaulniers
  2022-05-24 12:29     ` Miguel Ojeda
  1 sibling, 1 reply; 50+ messages in thread
From: Gary Guo @ 2022-05-23 23:41 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Jarkko Sakkinen, Alex Gaynor, Wedson Almeida Filho,
	Sven Van Asbroeck

On Mon, 23 May 2022 11:37:16 -0700
Nick Desaulniers <ndesaulniers@google.com> wrote:

> Also, I'm not sure my concern about explicit build failures for C code
> was ever addressed?  We have a constant problem with `long long`
> division on ARCH=arm32 and ARCH=i386 in C code.
> https://lore.kernel.org/lkml/CAKwvOdk+A2PBdjSFVUhj4xyCGCKujtej1uPgywQgrKPiK2ksPw@mail.gmail.com/
>
> > +#[cfg(target_arch = "arm")]
> > +define_panicking_intrinsics!("`u64` division/modulo should not be
> > used", {
> > +    __aeabi_uldivmod,
> > +    __mulodi4,
> > +});

Starting in LLVM 14 (used in Rust 1.60+), __mulodi4 will no longer be
generated. So that can be removed.

As for __aeabi_uldivmod, is there any reason that it can't just be
defined in arch/arm/lib? There are quite a few __aeabi functions already
defined there.

The source of __aeabi_uldivmod in compiler-rt seems quite simple, just
delegating to __uldivmoddi4. I think just changing that to
div64_u64_rem should do the job?

https://android.googlesource.com/toolchain/compiler-rt/+/release_32/lib/arm/aeabi_uldivmod.S

- Gary

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 06/25] rust: add `compiler_builtins` crate
  2022-05-23 18:37   ` Nick Desaulniers
  2022-05-23 23:41     ` Gary Guo
@ 2022-05-24 12:29     ` Miguel Ojeda
  1 sibling, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-24 12:29 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Jarkko Sakkinen, Alex Gaynor, Wedson Almeida Filho,
	Sven Van Asbroeck, Gary Guo

On Mon, May 23, 2022 at 8:37 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> ^ Any progress on this? Got any links to any feature requests or bug reports.

We got the floating point ones removed via a new feature flag
(https://github.com/rust-lang/rust/pull/86048) that Gary added (they
were already removed by the time of the message you link), so upstream
Rust is willing to add this sort of thing for us.

For the `i128`/`u128` ones, no change; but upstream Rust is aware of
this need (e.g. we presented them in the Rust CTCFT from November:
https://youtu.be/azcrUzeY3Pw?t=751).

See also https://github.com/Rust-for-Linux/linux/issues/2 and linked
issues there for more information.

> Also, I'm not sure my concern about explicit build failures for C code
> was ever addressed?  We have a constant problem with `long long`
> division on ARCH=arm32 and ARCH=i386 in C code.
> https://lore.kernel.org/lkml/CAKwvOdk+A2PBdjSFVUhj4xyCGCKujtej1uPgywQgrKPiK2ksPw@mail.gmail.com/

In my reply to that message I mentioned that the goal is to avoid the
panicking intrinsics to begin with. We already removed some, so I
would try to continue down that path. If that proves not possible,
then yeah, we would need something different.

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 04/25] kunit: take `kunit_assert` as `const`
  2022-05-23 18:14     ` Shuah Khan
@ 2022-05-24 12:37       ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-24 12:37 UTC (permalink / raw)
  To: Shuah Khan, Daniel Latypov
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Jarkko Sakkinen, Brendan Higgins,
	open list:KERNEL SELFTEST FRAMEWORK, KUnit Development

On Mon, May 23, 2022 at 8:14 PM Shuah Khan <skhan@linuxfoundation.org> wrote:
>
> On 5/23/22 11:15 AM, Daniel Latypov wrote:
> >
> > FYI, we'd asked Shuah to pick this patch up in her "kunit" branch.
> > It's applied here:
> > https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/commit/?h=kunit&id=7466886b400b1904ce30fa311904849e314a2cf4
> >
> > It had previously seemed unclear if this series could make it for the
> > 5.19 merge window (but it now looks like there's interest in trying it
> > out early on).
>
> I am just about send pull request with this patch included.

Thank you, Daniel and Shuah!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 21/25] Kbuild: add Rust support
  2022-05-23 18:44   ` Nick Desaulniers
@ 2022-05-24 15:12     ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-24 15:12 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Jarkko Sakkinen, Alex Gaynor, Finn Behrens,
	Adam Bratschi-Kaye, Wedson Almeida Filho, Michael Ellerman,
	Sven Van Asbroeck, Gary Guo, Boris-Chengbiao Zhou, Boqun Feng,
	Douglas Su, Dariusz Sosnowski, Antonio Terceiro, Daniel Xu,
	Miguel Cano, David Gow, Masahiro Yamada, Michal Marek,
	Russell King, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Paul Walmsley,
	Palmer Dabbelt, Albert Ou, Richard Weinberger, Anton Ivanov,
	Johannes Berg, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
	Dave Hansen, maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
	H. Peter Anvin, Linux Kbuild mailing list, Linux ARM,
	linuxppc-dev, linux-riscv, linux-um

On Mon, May 23, 2022 at 8:45 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> I'm super not into having the rust optimization level differ from the
> C optimization level.  This is just someone having too much fun
> wrapping every compiler flag in a kbuild option.  Either folks wan't

I mean, `Makefile`s are not my favorite pastime... :)

> smaller size or more optimizations. Allowing for RUST_OPT_LEVEL_S and
> CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE or RUST_OPT_LEVEL_3 and
> CONFIG_CC_OPTIMIZE_FOR_SIZE is just wacky nonsense that's going to
> make randconfig bug reports more confusing to tease out.

I think what is important is to decide whether extra levels, for C and
Rust, should be kept compile-able/maintained or not (I also replied in
the `-O1` for C thread [1]).

Note that the Rust side can be compiled as `-O0` or `-O1` at the
moment, which is something we do not have for the C side; thus having
only the C == Rust option means we will not have a configuration with
those anymore.

For me it is less complex to not have them, and I have not heard more
opinions on this, either for or against (apart from that thread
suggesting `-O1` for the C side), so if nobody else chimes in, I will
remove them.

[1] https://lore.kernel.org/lkml/CANiq72kySVvOQ7eqwe0Jzz3V0JTtrcqODHR9Ty4-sfDMdzP6XQ@mail.gmail.com/

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size
  2022-05-23 19:45   ` Jarkko Sakkinen
  2022-05-23 19:55     ` Jarkko Sakkinen
@ 2022-05-24 16:21     ` Miguel Ojeda
  2022-05-26  4:54       ` Jarkko Sakkinen
  1 sibling, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-24 16:21 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Boqun Feng, Kees Cook

On Mon, May 23, 2022 at 9:46 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> "Declare KSY_NAME_LEN, which describes the maximum length for a kernel
> symbol read by kallsyms from the input.  In read_symbol(), define the
> buffer to be of length "KSY_NAME_LEN + 1", which includes the terminator
> character."
>
> would be better.

Note that the patch is not declaring `KSYM_NAME_LEN`, but a new
constant for a fairly arbitrarily sized for an input buffer.

I am all for detailed commit messages, and I agree this can be
expanded. However, I think the first sentence of what you wrote should
be part of the docs of the constant, and the second one sounds like it
could be a comment on the code. Something like "Introduce
KSYM_NAME_LEN_BUFFER in place of the previously hardcoded size of the
input buffer (...)" would be better for a reviewer.

> You must split this then into two patches:

Note that the size is not really being increased in a meaningful way
-- the important bit is the introduction of the relationship between
constants. The changes are all meant as a replacement for the
previously hardcoded constant, so I don't think the split is a "must",
but we can do it.

We can even split this into 3 patches: clean up the unneeded `sizeof`,
replace (and, importantly, document) the hardcoded constant, and
finally introduce the relationship.

Thanks for taking a look!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side
  2022-05-23  2:17   ` Joe Perches
@ 2022-05-24 16:35     ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-24 16:35 UTC (permalink / raw)
  To: Joe Perches
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Jarkko Sakkinen, Kees Cook, Alex Gaynor,
	Wedson Almeida Filho, Andy Whitcroft, Dwaipayan Ray,
	Lukas Bulwahn

On Mon, May 23, 2022 at 4:17 AM Joe Perches <joe@perches.com> wrote:
>
> How many developers are required for a trivial patch?

We are sending the core series as a team, so by default I acknowledge
all the maintainers. But yeah, I could drop some of the
Co-developed-by's.

> and this should now use elsif

Yeah, will change.

By the way, I also thought about skipping the warning if the error is
there, e.g. wrapping everything else in an `else`, if you prefer.

Thanks for the very quick review!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512
  2022-05-23 20:31   ` Jarkko Sakkinen
@ 2022-05-24 18:07     ` Miguel Ojeda
  2022-05-27 16:25       ` Jarkko Sakkinen
  0 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-24 18:07 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Kees Cook, Petr Mladek, Alex Gaynor,
	Wedson Almeida Filho, Gary Guo, Boqun Feng, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Joe Lawrence, Peter Zijlstra,
	Ingo Molnar, Arnaldo Carvalho de Melo, Mark Rutland,
	Alexander Shishkin, Jiri Olsa, Namhyung Kim, live-patching,
	linux-perf-users

On Mon, May 23, 2022 at 10:33 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> There's no description what the patch does.

I am not sure what you mean. Both the subject and the last paragraph
describe what the patch does, while the rest gives the rationale
behind it.

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 06/25] rust: add `compiler_builtins` crate
  2022-05-23 23:41     ` Gary Guo
@ 2022-05-25 21:29       ` Nick Desaulniers
  0 siblings, 0 replies; 50+ messages in thread
From: Nick Desaulniers @ 2022-05-25 21:29 UTC (permalink / raw)
  To: Gary Guo
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Jarkko Sakkinen, Alex Gaynor, Wedson Almeida Filho,
	Sven Van Asbroeck, Linux ARM, Arnd Bergmann

 On Mon, May 23, 2022 at 4:42 PM Gary Guo <gary@garyguo.net> wrote:
>
> On Mon, 23 May 2022 11:37:16 -0700
> Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> > Also, I'm not sure my concern about explicit build failures for C code
> > was ever addressed?  We have a constant problem with `long long`
> > division on ARCH=arm32 and ARCH=i386 in C code.
> > https://lore.kernel.org/lkml/CAKwvOdk+A2PBdjSFVUhj4xyCGCKujtej1uPgywQgrKPiK2ksPw@mail.gmail.com/
> >
> > > +#[cfg(target_arch = "arm")]
> > > +define_panicking_intrinsics!("`u64` division/modulo should not be
> > > used", {
> > > +    __aeabi_uldivmod,
> > > +    __mulodi4,
> > > +});
>
> Starting in LLVM 14 (used in Rust 1.60+), __mulodi4 will no longer be
> generated. So that can be removed.

I'm familiar, but good catch. ;)
https://reviews.llvm.org/D108936
https://reviews.llvm.org/D108842
https://reviews.llvm.org/D108844
https://reviews.llvm.org/D112750
https://reviews.llvm.org/D108928
https://reviews.llvm.org/D108939
https://bugs.llvm.org/show_bug.cgi?id=28629
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103034

>
> As for __aeabi_uldivmod, is there any reason that it can't just be
> defined in arch/arm/lib? There are quite a few __aeabi functions already
> defined there.

Indeed.
arch/arm/kernel/armksyms.c and
arch/arm/lib/lib1funcs.S

This is the previous thread I recall w/ Linus:
https://lore.kernel.org/llvm/CAHk-=wiydA=Oay+NB2m2ewCHpPEcoU51qPFrzsekFoPu7QPtuw@mail.gmail.com/

If CONFIG_RUST provides those symbols, it will hide the linkage
failures that we try to use to spot & avoid 64b division that's open
coded using the / binary operator, rather than the kernel's do_div()
and friends.

>
> The source of __aeabi_uldivmod in compiler-rt seems quite simple, just
> delegating to __uldivmoddi4. I think just changing that to
> div64_u64_rem should do the job?

Maybe; send a patch and see what happens. There's probably other 32b
architectures that will need other symbols that also handle 64b
division though, so it's not as simple as providing __aeabi_uldivmod
for ARM.

There's probably someone from linux-arm-kernel that can provide
additional context.
https://lore.kernel.org/linux-arm-kernel/alpine.LFD.2.00.1104271305580.24613@xanadu.home/
is pretty old, but refers to policies that seem to pre-exist other
references to __aeabi_uldivmod on that list.

arch/nios2/kernel/nios2_ksyms.c exports __udivmoddi4, but it also
explicitly links against libgcc.  I'm guessing that's frowned upon,
but not out of the question relative to having the kernel ported to
the architecture at all.

>
> https://android.googlesource.com/toolchain/compiler-rt/+/release_32/lib/arm/aeabi_uldivmod.S

Here's the latest source.
https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/builtins/arm/aeabi_uldivmod.S
and __uldivmoddi4:
https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/builtins/udivmoddi4.c

By chance, does any of the rust code in this series use open coded
division w/ 64 bit operands (rather than using do_div) by accident?

I'm also curious about the panic message for 128b operands. IIUC,
those are functions that may have `long long` operands.  On 32b ARM,
which is ILP32, I'd have expected `long long` to be 64b, not 128b.
Message might be misleading.
-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 21/25] Kbuild: add Rust support
  2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
  2022-05-23 18:44   ` Nick Desaulniers
@ 2022-05-25 22:25   ` Nick Desaulniers
  2022-05-30 13:39     ` Miguel Ojeda
  2022-07-16  8:21   ` Masahiro Yamada
  2 siblings, 1 reply; 50+ messages in thread
From: Nick Desaulniers @ 2022-05-25 22:25 UTC (permalink / raw)
  To: Miguel Ojeda, Masahiro Yamada
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Jarkko Sakkinen, Alex Gaynor, Finn Behrens, Adam Bratschi-Kaye,
	Wedson Almeida Filho, Michael Ellerman, Sven Van Asbroeck,
	Gary Guo, Boris-Chengbiao Zhou, Boqun Feng, Douglas Su,
	Dariusz Sosnowski, Antonio Terceiro, Daniel Xu, Miguel Cano,
	David Gow, Michal Marek, Russell King, Catalin Marinas,
	Will Deacon, Benjamin Herrenschmidt, Paul Mackerras,
	Paul Walmsley, Palmer Dabbelt, Albert Ou, Richard Weinberger,
	Anton Ivanov, Johannes Berg, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, linux-kbuild,
	linux-arm-kernel, linuxppc-dev, linux-riscv, linux-um

On Sun, May 22, 2022 at 7:04 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> --- a/Makefile
> +++ b/Makefile
> @@ -120,6 +120,15 @@ endif
>
>  export KBUILD_CHECKSRC
>
> +# Enable "clippy" (a linter) as part of the Rust compilation.
> +#
> +# Use 'make CLIPPY=1' to enable it.
> +ifeq ("$(origin CLIPPY)", "command line")
> +  KBUILD_CLIPPY := $(CLIPPY)
> +endif

Is there a reason to not just turn clippy on always? Might be nicer to
start off with good practices by default. :^)

> @@ -1494,7 +1588,8 @@ MRPROPER_FILES += include/config include/generated          \
>                   certs/signing_key.pem \
>                   certs/x509.genkey \
>                   vmlinux-gdb.py \
> -                 *.spec
> +                 *.spec \
> +                 rust/target.json rust/libmacros.so
>
>  # clean - Delete most, but leave enough to build external modules
>  #
> @@ -1519,6 +1614,9 @@ $(mrproper-dirs):
>
>  mrproper: clean $(mrproper-dirs)
>         $(call cmd,rmfiles)
> +       @find . $(RCS_FIND_IGNORE) \
> +               \( -name '*.rmeta' \) \
> +               -type f -print | xargs rm -f

Are there *.rmeta directories that we _don't_ want to remove via `make
mrproper`? I'm curious why *.rmeta isn't just part of MRPROPER_FILES?

>
>  # distclean
>  #
> @@ -1606,6 +1704,23 @@ help:
>         @echo  '  kselftest-merge   - Merge all the config dependencies of'
>         @echo  '                      kselftest to existing .config.'
>         @echo  ''
> +       @echo  'Rust targets:'
> +       @echo  '  rustavailable   - Checks whether the Rust toolchain is'
> +       @echo  '                    available and, if not, explains why.'
> +       @echo  '  rustfmt         - Reformat all the Rust code in the kernel'
> +       @echo  '  rustfmtcheck    - Checks if all the Rust code in the kernel'
> +       @echo  '                    is formatted, printing a diff otherwise.'
> +       @echo  '  rustdoc         - Generate Rust documentation'
> +       @echo  '                    (requires kernel .config)'
> +       @echo  '  rusttest        - Runs the Rust tests'
> +       @echo  '                    (requires kernel .config; downloads external repos)'
> +       @echo  '  rust-analyzer   - Generate rust-project.json rust-analyzer support file'
> +       @echo  '                    (requires kernel .config)'
> +       @echo  '  dir/file.[os]   - Build specified target only'
> +       @echo  '  dir/file.i      - Build macro expanded source, similar to C preprocessing'
> +       @echo  '                    (run with RUSTFMT=n to skip reformatting if needed)'
> +       @echo  '  dir/file.ll     - Build the LLVM assembly file'

I don't think we need to repeat dir/* here again for rust. The
existing targets listed above (outside this hunk) make sense in both
contexts.

Does rustc really use .i as a conventional suffix for macro expanded
sources? (The C compiler might use the -x flag to override the guess
it would make based on the file extension; I'm curious if rustc can
ingest .i files or will it warn?)

> diff --git a/init/Kconfig b/init/Kconfig
> index ddcbefe535e9..3457cf596588 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> +config RUSTC_VERSION_TEXT
> +       string
> +       depends on RUST
> +       default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
> +
> +config BINDGEN_VERSION_TEXT
> +       string
> +       depends on RUST
> +       default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)

Are these two kconfigs used anywhere?

> diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
> index 0496efd6e117..83e850321eb6 100644
> --- a/scripts/Kconfig.include
> +++ b/scripts/Kconfig.include
> @@ -36,12 +36,12 @@ ld-option = $(success,$(LD) -v $(1))
>  as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -)
>
>  # check if $(CC) and $(LD) exist
> -$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
> +$(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found)

Not that it's important to do so, but a couple hunks s/compiler/C
compiler/. Those _could_ probably get submitted ahead of this, but not
important to do so.

> diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
> index 9f39b0130551..fe87389d52c0 100644
> --- a/scripts/Makefile.debug
> +++ b/scripts/Makefile.debug
> @@ -1,4 +1,5 @@
>  DEBUG_CFLAGS   :=
> +DEBUG_RUSTFLAGS        :=
>
>  ifdef CONFIG_DEBUG_INFO_SPLIT
>  DEBUG_CFLAGS   += -gsplit-dwarf
> @@ -10,6 +11,12 @@ ifndef CONFIG_AS_IS_LLVM
>  KBUILD_AFLAGS  += -Wa,-gdwarf-2
>  endif
>
> +ifdef CONFIG_DEBUG_INFO_REDUCED
> +DEBUG_RUSTFLAGS += -Cdebuginfo=1
> +else
> +DEBUG_RUSTFLAGS += -Cdebuginfo=2
> +endif
> +

How does enabling or disabling debug info work for rustc? I may have
missed it, but I was surprised to see no additional flags getting
passed to rustc based on CONFIG_DEBUG info.

> diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
> new file mode 100644
> index 000000000000..c146a3407183
> --- /dev/null
> +++ b/scripts/generate_rust_target.rs

Ah, that explains the host rust build infra.  Bravo! Hard coding the
target files was my major concern last I looked at the series. I'm
very happy to see it be generated properly from .config!

I haven't actually reviewed this yet, but it makes me significantly
more confident in the series to see this approach added. Good job
whoever wrote this.

> diff --git a/scripts/is_rust_module.sh b/scripts/is_rust_module.sh
> new file mode 100755
> index 000000000000..277a64d07f22
> --- /dev/null
> +++ b/scripts/is_rust_module.sh
> @@ -0,0 +1,13 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# is_rust_module.sh module.ko
> +#
> +# Returns `0` if `module.ko` is a Rust module, `1` otherwise.
> +
> +set -e
> +
> +# Using the `16_` prefix ensures other symbols with the same substring
> +# are not picked up (even if it would be unlikely). The last part is
> +# used just in case LLVM decides to use the `.` suffix.
> +${NM} "$*" | grep -qE '^[0-9a-fA-F]+ r _R[^[:space:]]+16___IS_RUST_MODULE[^[:space:]]*$'

Does `$(READELF) -p .comment foo.o` print anything about which
compiler was used? That seems less brittle IMO.

---

Modulo the RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C which I'm not a fan
of, this is looking good to me. Masahiro, what are your thoughts on
the build system support?
-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size
  2022-05-24 16:21     ` Miguel Ojeda
@ 2022-05-26  4:54       ` Jarkko Sakkinen
  0 siblings, 0 replies; 50+ messages in thread
From: Jarkko Sakkinen @ 2022-05-26  4:54 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Boqun Feng, Kees Cook

On Tue, May 24, 2022 at 06:21:14PM +0200, Miguel Ojeda wrote:
> On Mon, May 23, 2022 at 9:46 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
> >
> > "Declare KSY_NAME_LEN, which describes the maximum length for a kernel
> > symbol read by kallsyms from the input.  In read_symbol(), define the
> > buffer to be of length "KSY_NAME_LEN + 1", which includes the terminator
> > character."
> >
> > would be better.
> 
> Note that the patch is not declaring `KSYM_NAME_LEN`, but a new
> constant for a fairly arbitrarily sized for an input buffer.
> 
> I am all for detailed commit messages, and I agree this can be
> expanded. However, I think the first sentence of what you wrote should
> be part of the docs of the constant, and the second one sounds like it
> could be a comment on the code. Something like "Introduce
> KSYM_NAME_LEN_BUFFER in place of the previously hardcoded size of the
> input buffer (...)" would be better for a reviewer.

Inline comment would be sufficient a remainder, and actually a better
idea.

> > You must split this then into two patches:
> 
> Note that the size is not really being increased in a meaningful way
> -- the important bit is the introduction of the relationship between
> constants. The changes are all meant as a replacement for the
> previously hardcoded constant, so I don't think the split is a "must",
> but we can do it.
> 
> We can even split this into 3 patches: clean up the unneeded `sizeof`,
> replace (and, importantly, document) the hardcoded constant, and
> finally introduce the relationship.
> 
> Thanks for taking a look!
> 
> Cheers,
> Miguel

BR, Jarkko

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512
  2022-05-24 18:07     ` Miguel Ojeda
@ 2022-05-27 16:25       ` Jarkko Sakkinen
  2022-05-30 13:01         ` Miguel Ojeda
  0 siblings, 1 reply; 50+ messages in thread
From: Jarkko Sakkinen @ 2022-05-27 16:25 UTC (permalink / raw)
  To: Miguel Ojeda, David Howells
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	linux-kernel, Kees Cook, Petr Mladek, Alex Gaynor,
	Wedson Almeida Filho, Gary Guo, Boqun Feng, Josh Poimboeuf,
	Jiri Kosina, Miroslav Benes, Joe Lawrence, Peter Zijlstra,
	Ingo Molnar, Arnaldo Carvalho de Melo, Mark Rutland,
	Alexander Shishkin, Jiri Olsa, Namhyung Kim, live-patching,
	linux-perf-users

On Tue, 2022-05-24 at 20:07 +0200, Miguel Ojeda wrote:
> On Mon, May 23, 2022 at 10:33 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
> > 
> > There's no description what the patch does.
> 
> I am not sure what you mean. Both the subject and the last paragraph
> describe what the patch does, while the rest gives the rationale
> behind it.
> 
> Cheers,
> Miguel

The honest answer: I don't actually remember what I was thinking 
(other stuff stole my focus) but my comment neither makes much
sense to me. Please just ignore it, and apologies for causing
confusion.

There's something I'm looking into in my spare time right now.
I'm experimenting with interfacing keyring types to Rust. The
first step, I guess, is to provide a Rust abstraction for
assoc_array.

I've skimmed through the patch set and have now *rough* idea of
patterns and techniques. My opens are more on the process side
of things since there's no yet mainline subtree.

If I send a patch or patch sets, would this be a good workflow:

1. RFC tag.
2. In the cover letter denote the patch set version, which was
   used the baseline.

Linux keyring is without argument a kind of subsystem that would
hugely benefit of the Rust work, as it is both user space facing 
nd handling a vast amount of user's confidential data. 

BR, Jarkko

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512
  2022-05-27 16:25       ` Jarkko Sakkinen
@ 2022-05-30 13:01         ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-30 13:01 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: David Howells, Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman,
	rust-for-linux, linux-kernel, Kees Cook, Petr Mladek,
	Alex Gaynor, Wedson Almeida Filho, Gary Guo, Boqun Feng,
	Josh Poimboeuf, Jiri Kosina, Miroslav Benes, Joe Lawrence,
	Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
	Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
	live-patching, linux-perf-users

On Fri, May 27, 2022 at 6:27 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> The honest answer: I don't actually remember what I was thinking
> (other stuff stole my focus) but my comment neither makes much
> sense to me. Please just ignore it, and apologies for causing
> confusion.

No apologies needed!

> There's something I'm looking into in my spare time right now.
> I'm experimenting with interfacing keyring types to Rust. The
> first step, I guess, is to provide a Rust abstraction for
> assoc_array.
>
> I've skimmed through the patch set and have now *rough* idea of
> patterns and techniques. My opens are more on the process side
> of things since there's no yet mainline subtree.

Thanks a lot for taking a look and taking the initiative.

> If I send a patch or patch sets, would this be a good workflow:
>
> 1. RFC tag.
> 2. In the cover letter denote the patch set version, which was
>    used the baseline.

Sounds good to me. Alternatively, you can use a `--base=` pointing to
one of the commits in our `rust` branch.

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 21/25] Kbuild: add Rust support
  2022-05-25 22:25   ` Nick Desaulniers
@ 2022-05-30 13:39     ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-05-30 13:39 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: Miguel Ojeda, Masahiro Yamada, Linus Torvalds,
	Greg Kroah-Hartman, rust-for-linux, linux-kernel,
	Jarkko Sakkinen, Alex Gaynor, Finn Behrens, Adam Bratschi-Kaye,
	Wedson Almeida Filho, Michael Ellerman, Sven Van Asbroeck,
	Gary Guo, Boris-Chengbiao Zhou, Boqun Feng, Douglas Su,
	Dariusz Sosnowski, Antonio Terceiro, Daniel Xu, Miguel Cano,
	David Gow, Michal Marek, Russell King, Catalin Marinas,
	Will Deacon, Benjamin Herrenschmidt, Paul Mackerras,
	Paul Walmsley, Palmer Dabbelt, Albert Ou, Richard Weinberger,
	Anton Ivanov, Johannes Berg, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, Dave Hansen,
	maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT),
	H. Peter Anvin, Linux Kbuild mailing list, Linux ARM,
	linuxppc-dev, linux-riscv, linux-um

On Thu, May 26, 2022 at 12:25 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> Is there a reason to not just turn clippy on always? Might be nicer to
> start off with good practices by default. :^)

The idea crossed my mind too [1], but sadly Clippy disables some
optimizations and in general is not intended to be used for normal
compilation [2].

[1] https://github.com/rust-lang/rust-clippy/issues/8035
[2] https://github.com/rust-lang/rust-clippy/pull/8037

> Are there *.rmeta directories that we _don't_ want to remove via `make
> mrproper`? I'm curious why *.rmeta isn't just part of MRPROPER_FILES?

Putting them in `MRPROPER_FILES` would mean only those in a given
directory are removed (e.g. the root one), but the idea here is to
find them anywhere in the tree, since in the future we may have
library crates in different parts of the tree.

However, I am not sure I understand your first question in relation
with the second one -- if we put them in `MRPROPER_FILES`, that would
remove less, not more.

> I don't think we need to repeat dir/* here again for rust. The
> existing targets listed above (outside this hunk) make sense in both
> contexts.

The idea here is to document the differences (e.g. `RUSTFMT`) and that
we may have other targets in the future that do not apply to C (e.g.
MIR dump, if that happens to be useful).

But maybe I can fit that in the normal place and make it still look
good... I will give it a try.

> Does rustc really use .i as a conventional suffix for macro expanded
> sources? (The C compiler might use the -x flag to override the guess

It is not a conventional suffix at all as far as I am aware.

Maybe we should use a different one to aid editors and users anyway,
e.g. `.rsi`, similar to `.mi` for Objective-C `.m` files.

> it would make based on the file extension; I'm curious if rustc can
> ingest .i files or will it warn?)

The macro expanded output is not intended to be used as a compilable
input, but as a debugging aid only. I can note this there.

Having said that, `rustc` accepts the "preprocessed" output in the
sense that it will just treat them as normal source files (no flag
needed, and e.g. both `.i` and `.rsi` work); however, it may give new
diagnostics or may require extra flags to enable some compiler
features.

From a quick test, I managed to compile a "preprocessed" Rust kernel
module with only command-line changes. But if we really wanted to
support this, we would need to ask upstream Rust to actually support
it.

> Are these two kconfigs used anywhere?

Not for the moment, but it could still be useful when getting
`.config` reports (and we could add it to `LINUX_COMPILER` etc. in the
future).

> How does enabling or disabling debug info work for rustc? I may have
> missed it, but I was surprised to see no additional flags getting
> passed to rustc based on CONFIG_DEBUG info.

`-Cdebuginfo=` is the one; by default there is no debug info and that
option enables it (i.e. it is not just the level but the enablement
too).

(Note that in userspace, when compiling a common program, you will get
some debug info coming from the standard library and other
dependencies).

> Ah, that explains the host rust build infra.  Bravo! Hard coding the
> target files was my major concern last I looked at the series. I'm
> very happy to see it be generated properly from .config!
>
> I haven't actually reviewed this yet, but it makes me significantly
> more confident in the series to see this approach added. Good job
> whoever wrote this.

Thanks! I thought Rust would be a nice option for writing hostprogs,
though of course for the moment only programs that can assume Rust is
there may use it.

Note that non-x86 specific options need to be handled properly still
(e.g. move things between the arch Makefiles and the hostprog as
needed).

I would still want to see compilers come to some kind of common format
for this as we discussed other times, but... :)

> Does `$(READELF) -p .comment foo.o` print anything about which
> compiler was used? That seems less brittle IMO.

Currently, `rustc` does not add a `.comment` section; but we could
ask, I sent [3].

If debug info is enabled, another way is using the `DW_AT_language`
attribute, like `pahole` will be doing for a new option we need [4].
However, we would still need a way for the other case.

In any case, I am not sure something like `.comment` is less or more
brittle -- compilers could in theory change it (e.g. not emitting it),
while adding a symbol is something we control. So different kinds of
brittleness.

[3] https://github.com/rust-lang/rust/pull/97550
[4] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 21/25] Kbuild: add Rust support
  2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
  2022-05-23 18:44   ` Nick Desaulniers
  2022-05-25 22:25   ` Nick Desaulniers
@ 2022-07-16  8:21   ` Masahiro Yamada
  2022-07-16  8:57     ` Miguel Ojeda
  2 siblings, 1 reply; 50+ messages in thread
From: Masahiro Yamada @ 2022-07-16  8:21 UTC (permalink / raw)
  To: Miguel Ojeda
  Cc: Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	Linux Kernel Mailing List, Jarkko Sakkinen, Alex Gaynor,
	Finn Behrens, Adam Bratschi-Kaye, Wedson Almeida Filho,
	Michael Ellerman, Sven Van Asbroeck, Gary Guo,
	Boris-Chengbiao Zhou, Boqun Feng, Douglas Su, Dariusz Sosnowski,
	Antonio Terceiro, Daniel Xu, Miguel Cano, David Gow,
	Michal Marek, Nick Desaulniers, Russell King, Catalin Marinas,
	Will Deacon, Benjamin Herrenschmidt, Paul Mackerras,
	Paul Walmsley, Palmer Dabbelt, Albert Ou, Richard Weinberger,
	Anton Ivanov, Johannes Berg, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, Dave Hansen, X86 ML, H. Peter Anvin,
	Linux Kbuild mailing list, linux-arm-kernel, linuxppc-dev,
	open list:SIFIVE DRIVERS, linux-um

On Mon, May 23, 2022 at 11:04 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Having all the new files in place, we now enable Rust support
> in the build system, including `Kconfig` entries related to Rust,
> the Rust configuration printer, the target specification
> generation script, the version detection script and a few
> other bits.
>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Finn Behrens <me@kloenk.de>
> Signed-off-by: Finn Behrens <me@kloenk.de>
> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
> Co-developed-by: Gary Guo <gary@garyguo.net>
> Signed-off-by: Gary Guo <gary@garyguo.net>
> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
> Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Co-developed-by: Douglas Su <d0u9.su@outlook.com>
> Signed-off-by: Douglas Su <d0u9.su@outlook.com>
> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org>
> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org>
> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz>
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> Co-developed-by: Miguel Cano <macanroj@gmail.com>
> Signed-off-by: Miguel Cano <macanroj@gmail.com>
> Co-developed-by: David Gow <davidgow@google.com>
> Signed-off-by: David Gow <davidgow@google.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---





> +# Rust targets
> +# ---------------------------------------------------------------------------
> +
> +# "Is Rust available?" target
> +PHONY += rustavailable
> +rustavailable:
> +       $(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v && echo >&2 "Rust is available!"
> +

Is it intentional to print the successful message to stderr?



-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 21/25] Kbuild: add Rust support
  2022-07-16  8:21   ` Masahiro Yamada
@ 2022-07-16  8:57     ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-07-16  8:57 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Miguel Ojeda, Linus Torvalds, Greg Kroah-Hartman, rust-for-linux,
	Linux Kernel Mailing List, Jarkko Sakkinen, Alex Gaynor,
	Finn Behrens, Adam Bratschi-Kaye, Wedson Almeida Filho,
	Michael Ellerman, Sven Van Asbroeck, Gary Guo,
	Boris-Chengbiao Zhou, Boqun Feng, Douglas Su, Dariusz Sosnowski,
	Antonio Terceiro, Daniel Xu, Miguel Cano, David Gow,
	Michal Marek, Nick Desaulniers, Russell King, Catalin Marinas,
	Will Deacon, Benjamin Herrenschmidt, Paul Mackerras,
	Paul Walmsley, Palmer Dabbelt, Albert Ou, Richard Weinberger,
	Anton Ivanov, Johannes Berg, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, Dave Hansen, X86 ML, H. Peter Anvin,
	Linux Kbuild mailing list, linux-arm-kernel, linuxppc-dev,
	open list:SIFIVE DRIVERS, linux-um

Hi Masahiro,

On Sat, Jul 16, 2022 at 10:23 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Is it intentional to print the successful message to stderr?

I think it makes sense to change it to `stdout`, given the message is
the main point of running `rustavailable` for normal users, and those
that just want the status code may ignore it.

Thanks for taking a look again!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 00/25] Rust support
  2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
                   ` (20 preceding siblings ...)
  2022-05-23  2:01 ` [PATCH v7 24/25] [RFC] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda
@ 2022-07-16 12:42 ` Conor Dooley
  2022-07-16 13:36   ` Miguel Ojeda
  21 siblings, 1 reply; 50+ messages in thread
From: Conor Dooley @ 2022-07-16 12:42 UTC (permalink / raw)
  To: ojeda
  Cc: gregkh, jarkko, kunit-dev, linux-arm-kernel, linux-doc,
	linux-gpio, linux-kbuild, linux-kernel, linux-kselftest,
	linux-perf-users, linux-riscv, linux-um, linuxppc-dev,
	live-patching, rust-for-linux, torvalds

Hey,

Maybe I am just missing something blatantly obvious here, but trying
to build rust support in -next fails for me. I am using ClangBuiltLinux
clang version 15.0.0 5b0788fef86ed7008a11f6ee19b9d86d42b6fcfa and LLD
15.0.0. Is it just expected that building -next with rust support is
not a good idea?
My defconfig is the default RISC-V one plus:
CONFIG_RUST=y
CONFIG_SAMPLES=y
CONFIG_SAMPLES_RUST=y
CONFIG_SAMPLE_RUST_MINIMAL=y

Thanks,
Conor.

Fail log:
  UPD     rust/target.json
  BINDGEN rust/bindings_generated.rs
  BINDGEN rust/bindings_helpers_generated.rs
  RUSTC L rust/core.o
  EXPORTS rust/exports_core_generated.h
  RUSTC P rust/libmacros.so
  RUSTC L rust/compiler_builtins.o
  RUSTC L rust/alloc.o
  RUSTC L rust/build_error.o
  EXPORTS rust/exports_alloc_generated.h
  RUSTC L rust/kernel.o
error[E0428]: the name `maple_enode` is defined multiple times
     --> linux/rust/bindings_generated.rs:18009:1
      |
18006 | pub struct maple_enode {
      | ---------------------- previous definition of the type `maple_enode` here
...
18009 | pub type maple_enode = *mut maple_enode;
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `maple_enode` redefined here
      |
      = note: `maple_enode` must be defined only once in the type namespace of this module

error[E0428]: the name `maple_pnode` is defined multiple times
     --> linux/rust/bindings_generated.rs:18015:1
      |
18012 | pub struct maple_pnode {
      | ---------------------- previous definition of the type `maple_pnode` here
...
18015 | pub type maple_pnode = *mut maple_pnode;
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `maple_pnode` redefined here
      |
      = note: `maple_pnode` must be defined only once in the type namespace of this module

error[E0391]: cycle detected when expanding type alias `bindings::bindings_raw::maple_pnode`
     --> linux/rust/bindings_generated.rs:18015:29
      |
18015 | pub type maple_pnode = *mut maple_pnode;
      |                             ^^^^^^^^^^^
      |
      = note: ...which immediately requires expanding type alias `bindings::bindings_raw::maple_pnode` again
      = note: type aliases cannot be recursive
      = help: consider using a struct, enum, or union instead to break the cycle
      = help: see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information
note: cycle used when computing type of `bindings::bindings_raw::maple_range_64::parent`
     --> linux/rust/bindings_generated.rs:18058:22
      |
18058 |     pub parent: *mut maple_pnode,
      |                      ^^^^^^^^^^^

error[E0391]: cycle detected when expanding type alias `bindings::bindings_raw::maple_enode`
     --> linux/rust/bindings_generated.rs:18009:29
      |
18009 | pub type maple_enode = *mut maple_enode;
      |                             ^^^^^^^^^^^
      |
      = note: ...which immediately requires expanding type alias `bindings::bindings_raw::maple_enode` again
      = note: type aliases cannot be recursive
      = help: consider using a struct, enum, or union instead to break the cycle
      = help: see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information
note: cycle used when computing type of `bindings::bindings_raw::maple_topiary::next`
     --> linux/rust/bindings_generated.rs:18340:20
      |
18340 |     pub next: *mut maple_enode,
      |                    ^^^^^^^^^^^

error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
     --> linux/rust/bindings_generated.rs:18005:10
      |
18005 | #[derive(Copy, Clone)]
      |          ^^^^
      |          |
      |          impl doesn't use only types from inside the current crate
      |          `*mut [type error]` is not defined in the current crate
      |
      = note: define and implement a trait or new type instead
      = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
     --> linux/rust/bindings_generated.rs:18011:10
      |
18011 | #[derive(Copy, Clone)]
      |          ^^^^
      |          |
      |          impl doesn't use only types from inside the current crate
      |          `*mut [type error]` is not defined in the current crate
      |
      = note: define and implement a trait or new type instead
      = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
     --> linux/rust/bindings_generated.rs:18005:16
      |
18005 | #[derive(Copy, Clone)]
      |                ^^^^^
      |                |
      |                impl doesn't use only types from inside the current crate
      |                `*mut [type error]` is not defined in the current crate
      |
      = note: define and implement a trait or new type instead
      = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0117]: only traits defined in the current crate can be implemented for arbitrary types
     --> linux/rust/bindings_generated.rs:18011:16
      |
18011 | #[derive(Copy, Clone)]
      |                ^^^^^
      |                |
      |                impl doesn't use only types from inside the current crate
      |                `*mut [type error]` is not defined in the current crate
      |
      = note: define and implement a trait or new type instead
      = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 8 previous errors

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 00/25] Rust support
  2022-07-16 12:42 ` [PATCH v7 00/25] Rust support Conor Dooley
@ 2022-07-16 13:36   ` Miguel Ojeda
  2022-07-16 13:51     ` Conor.Dooley
  0 siblings, 1 reply; 50+ messages in thread
From: Miguel Ojeda @ 2022-07-16 13:36 UTC (permalink / raw)
  To: Conor Dooley
  Cc: Miguel Ojeda, Greg KH, Jarkko Sakkinen, KUnit Development,
	Linux ARM, Linux Doc Mailing List, open list:GPIO SUBSYSTEM,
	Linux Kbuild mailing list, linux-kernel,
	open list:KERNEL SELFTEST FRAMEWORK, linux-perf-users,
	linux-riscv, linux-um, linuxppc-dev, live-patching,
	rust-for-linux, Linus Torvalds

Hi Conor,

On Sat, Jul 16, 2022 at 2:42 PM Conor Dooley <conor@kernel.org> wrote:
>
> Maybe I am just missing something blatantly obvious here, but trying
> to build rust support in -next fails for me. I am using ClangBuiltLinux
> clang version 15.0.0 5b0788fef86ed7008a11f6ee19b9d86d42b6fcfa and LLD
> 15.0.0. Is it just expected that building -next with rust support is
> not a good idea?

Please see https://github.com/Rust-for-Linux/linux/issues/795 for
details about the maple tree issue.

I will update the `rust-next` branch next week with the new version of
the patches; but if you are interested in developing, please use the
development `rust` branch instead in GitHub for the moment.

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 00/25] Rust support
  2022-07-16 13:36   ` Miguel Ojeda
@ 2022-07-16 13:51     ` Conor.Dooley
  2022-07-16 13:56       ` Miguel Ojeda
  0 siblings, 1 reply; 50+ messages in thread
From: Conor.Dooley @ 2022-07-16 13:51 UTC (permalink / raw)
  To: miguel.ojeda.sandonis, conor
  Cc: ojeda, gregkh, jarkko, kunit-dev, linux-arm-kernel, linux-doc,
	linux-gpio, linux-kbuild, linux-kernel, linux-kselftest,
	linux-perf-users, linux-riscv, linux-um, linuxppc-dev,
	live-patching, rust-for-linux, torvalds

On 16/07/2022 14:36, Miguel Ojeda wrote:
> Hi Conor,
> 
> On Sat, Jul 16, 2022 at 2:42 PM Conor Dooley <conor@kernel.org> wrote:
>>
>> Maybe I am just missing something blatantly obvious here, but trying
>> to build rust support in -next fails for me. I am using ClangBuiltLinux
>> clang version 15.0.0 5b0788fef86ed7008a11f6ee19b9d86d42b6fcfa and LLD
>> 15.0.0. Is it just expected that building -next with rust support is
>> not a good idea?
> 
> Please see https://github.com/Rust-for-Linux/linux/issues/795 for
> details about the maple tree issue.

Ah right, sorry for the noise so. I checked the ml but didn't see a
report there.

> 
> I will update the `rust-next` branch next week with the new version of
> the patches; but if you are interested in developing, please use the
> development `rust` branch instead in GitHub for the moment.

Thanks Miguel, good to know! I'll just wait around for a new version.
Just been trying to get my CI etc in order for when rust support lands,
but it sounds like I should be okay as it's a known problem & not some
only-broken-on-riscv thing.

Thanks,
Conor.

^ permalink raw reply	[flat|nested] 50+ messages in thread

* Re: [PATCH v7 00/25] Rust support
  2022-07-16 13:51     ` Conor.Dooley
@ 2022-07-16 13:56       ` Miguel Ojeda
  0 siblings, 0 replies; 50+ messages in thread
From: Miguel Ojeda @ 2022-07-16 13:56 UTC (permalink / raw)
  To: Conor.Dooley
  Cc: Conor Dooley, Miguel Ojeda, Greg KH, Jarkko Sakkinen,
	KUnit Development, Linux ARM, Linux Doc Mailing List,
	open list:GPIO SUBSYSTEM, Linux Kbuild mailing list,
	linux-kernel, open list:KERNEL SELFTEST FRAMEWORK,
	linux-perf-users, linux-riscv, linux-um, linuxppc-dev,
	live-patching, rust-for-linux, Linus Torvalds

On Sat, Jul 16, 2022 at 3:51 PM <Conor.Dooley@microchip.com> wrote:
>
> Ah right, sorry for the noise so. I checked the ml but didn't see a
> report there.

No apologies needed -- thanks to you for the report, instead! :)

> Thanks Miguel, good to know! I'll just wait around for a new version.
> Just been trying to get my CI etc in order for when rust support lands,
> but it sounds like I should be okay as it's a known problem & not some
> only-broken-on-riscv thing.

Yeah, it is a simple `bindgen` issue. Thanks a lot for making the
effort to prepare your CI in advance!

Cheers,
Miguel

^ permalink raw reply	[flat|nested] 50+ messages in thread

end of thread, other threads:[~2022-07-16 13:56 UTC | newest]

Thread overview: 50+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-23  2:01 [PATCH v7 00/25] Rust support Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 01/25] kallsyms: avoid hardcoding the buffer size Miguel Ojeda
2022-05-23 19:45   ` Jarkko Sakkinen
2022-05-23 19:55     ` Jarkko Sakkinen
2022-05-24 16:21     ` Miguel Ojeda
2022-05-26  4:54       ` Jarkko Sakkinen
2022-05-23  2:01 ` [PATCH v7 02/25] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-05-23 20:30   ` Jarkko Sakkinen
2022-05-23  2:01 ` [PATCH v7 03/25] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-05-23 20:31   ` Jarkko Sakkinen
2022-05-24 18:07     ` Miguel Ojeda
2022-05-27 16:25       ` Jarkko Sakkinen
2022-05-30 13:01         ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 04/25] kunit: take `kunit_assert` as `const` Miguel Ojeda
2022-05-23 17:15   ` Daniel Latypov
2022-05-23 18:14     ` Shuah Khan
2022-05-24 12:37       ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 05/25] rust: add C helpers Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 06/25] rust: add `compiler_builtins` crate Miguel Ojeda
2022-05-23 18:37   ` Nick Desaulniers
2022-05-23 23:41     ` Gary Guo
2022-05-25 21:29       ` Nick Desaulniers
2022-05-24 12:29     ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 08/25] rust: adapt `alloc` crate to the kernel Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 09/25] rust: add `build_error` crate Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 10/25] rust: add `macros` crate Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 13/25] rust: export generated symbols Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 14/25] vsprintf: add new `%pA` format specifier Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side Miguel Ojeda
2022-05-23  2:17   ` Joe Perches
2022-05-24 16:35     ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 16/25] scripts: checkpatch: enable language-independent checks for Rust Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 17/25] scripts: add `rustdoc_test_{builder,gen}.py` scripts Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 18/25] scripts: add `generate_rust_analyzer.py` scripts Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 19/25] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 20/25] docs: add Rust documentation Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 21/25] Kbuild: add Rust support Miguel Ojeda
2022-05-23 18:44   ` Nick Desaulniers
2022-05-24 15:12     ` Miguel Ojeda
2022-05-25 22:25   ` Nick Desaulniers
2022-05-30 13:39     ` Miguel Ojeda
2022-07-16  8:21   ` Masahiro Yamada
2022-07-16  8:57     ` Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 22/25] samples: add Rust examples Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 23/25] MAINTAINERS: Rust Miguel Ojeda
2022-05-23  2:01 ` [PATCH v7 24/25] [RFC] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda
2022-07-16 12:42 ` [PATCH v7 00/25] Rust support Conor Dooley
2022-07-16 13:36   ` Miguel Ojeda
2022-07-16 13:51     ` Conor.Dooley
2022-07-16 13:56       ` Miguel Ojeda

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