From: Benjamin Gray <bgray@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: ajd@linux.ibm.com, peterz@infradead.org,
Benjamin Gray <bgray@linux.ibm.com>,
npiggin@gmail.com, ardb@kernel.org, jbaron@akamai.com,
rostedt@goodmis.org, jpoimboe@kernel.org
Subject: [PATCH v3 0/6] Out-of-line static calls for powerpc64 ELF V2
Date: Wed, 5 Oct 2022 16:32:28 +1100 [thread overview]
Message-ID: <20221005053234.29312-1-bgray@linux.ibm.com> (raw)
Implementation of out-of-line static calls for PowerPC 64-bit ELF V2 ABI.
Static calls patch an indirect branch into a direct branch at runtime.
Out-of-line specifically has a caller directly call a trampoline, and
the trampoline gets patched to directly call the target.
Previous versions here:
V2: https://lore.kernel.org/all/20220926064316.765967-1-bgray@linux.ibm.com/
V1: https://lore.kernel.org/all/20220916062330.430468-1-bgray@linux.ibm.com/
Changed for V3:
[general]
* Rebased on top of
https://lore.kernel.org/all/0df84a2eea551c1d000c34c36d0c1d23cbe26a97.1664289176.git.christophe.leroy@csgroup.eu/
for removing the separate CONFIG_STRICT_KERNEL_RWX cases. Can rebase back onto next if necessary.
* Some some minor refactoring/style fixes throughout
[1/6]
* Code patching rewritten again
* This time it only adds support for what is needed:
* int or long sized writes only
* assumed within a cacheline (static call pointers are aligned
for atomic updates, instructions are aligned anyway)
* unconditional instruction syncing because non-instruction
patching is not used in any performance sensitive paths
* similarly, dword case is marked unlikely. ftrace activation is biggest
performance concern, and it only uses non-prefixed instructions.
* Should be zero difference on 32-bit, minor differences on 64-bit
* Design doesn't need to be revisited unless specifically 1 or 2 byte
patching is needed. Most such patches can be emulated by read-update-store
of 4 bytes. Non-cacheline safe patches can be split similarly (they
can't have atomicity requirements if they aren't aligned).
[3/6]
* Refactored to use patch_branch (thx Christophe)
[5/6]
* Required .localentry NAME, 1 directive guarded by toolchain version check
* Removed #ifdef's from static call implementation. Added sign_extend_long to
support this.
* Fixed a bug in ppc_function_toc handling of lis case & made it more verbose
to make such errors stand out more. New layout splits into calculating required
values, and then applying them in two steps.
[6/6]
* Replaced SAVE_REGS/RESTORE_REGS macros with functions
* Reduced global register usage of tests
* Support running on 32-bit as well
Benjamin Gray (6):
powerpc/code-patching: Implement generic text patching function
powerpc/module: Handle caller-saved TOC in module linker
powerpc/module: Optimise nearby branches in ELF V2 ABI stub
static_call: Move static call selftest to static_call_selftest.c
powerpc/64: Add support for out-of-line static calls
powerpc: Add tests for out-of-line static calls
arch/powerpc/Kconfig | 26 ++-
arch/powerpc/include/asm/code-patching.h | 30 +++
arch/powerpc/include/asm/static_call.h | 80 ++++++-
arch/powerpc/kernel/Makefile | 4 +-
arch/powerpc/kernel/module_64.c | 26 ++-
arch/powerpc/kernel/static_call.c | 183 +++++++++++++++-
arch/powerpc/kernel/static_call_test.c | 263 +++++++++++++++++++++++
arch/powerpc/kernel/static_call_test.h | 56 +++++
arch/powerpc/lib/code-patching.c | 73 +++++--
kernel/Makefile | 1 +
kernel/static_call_inline.c | 43 ----
kernel/static_call_selftest.c | 41 ++++
12 files changed, 753 insertions(+), 73 deletions(-)
create mode 100644 arch/powerpc/kernel/static_call_test.c
create mode 100644 arch/powerpc/kernel/static_call_test.h
create mode 100644 kernel/static_call_selftest.c
base-commit: 9a5e80596e50f1ab19fecb2d337e7ea3287ee083
--
2.37.3
next reply other threads:[~2022-10-05 5:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-05 5:32 Benjamin Gray [this message]
2022-10-05 5:32 ` [PATCH v3 1/6] powerpc/code-patching: Implement generic text patching function Benjamin Gray
2022-10-05 17:55 ` Christophe Leroy
2022-10-06 3:36 ` Benjamin Gray
2022-10-06 9:19 ` Christophe Leroy
2022-10-06 21:53 ` Benjamin Gray
2022-10-05 5:32 ` [PATCH v3 2/6] powerpc/module: Handle caller-saved TOC in module linker Benjamin Gray
2022-10-05 19:18 ` Christophe Leroy
2022-10-06 3:51 ` Andrew Donnellan
2022-10-06 4:39 ` Benjamin Gray
2022-10-05 5:32 ` [PATCH v3 3/6] powerpc/module: Optimise nearby branches in ELF V2 ABI stub Benjamin Gray
2022-10-05 19:21 ` Christophe Leroy
2022-10-06 8:24 ` Andrew Donnellan
2022-10-05 5:32 ` [PATCH v3 4/6] static_call: Move static call selftest to static_call_selftest.c Benjamin Gray
2022-10-05 19:22 ` Christophe Leroy
2022-10-05 5:32 ` [PATCH v3 5/6] powerpc/64: Add support for out-of-line static calls Benjamin Gray
2022-10-05 19:38 ` Christophe Leroy
2022-10-06 0:39 ` Michael Ellerman
2022-10-06 5:01 ` Benjamin Gray
2022-10-06 18:22 ` Segher Boessenkool
2022-10-06 18:38 ` Christophe Leroy
2022-10-06 20:45 ` Segher Boessenkool
2022-10-06 20:50 ` Christophe Leroy
2022-10-06 21:04 ` Segher Boessenkool
2022-10-05 5:32 ` [PATCH v3 6/6] powerpc: Add tests " Benjamin Gray
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