From: Miguel Ojeda <ojeda@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, patches@lists.linux.dev,
Jarkko Sakkinen <jarkko@kernel.org>,
Miguel Ojeda <ojeda@kernel.org>, Gary Guo <gary@garyguo.net>,
Kees Cook <keescook@chromium.org>, Petr Mladek <pmladek@suse.com>,
Alex Gaynor <alex.gaynor@gmail.com>,
Wedson Almeida Filho <wedsonaf@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org
Subject: [PATCH v9 14/27] vsprintf: add new `%pA` format specifier
Date: Fri, 5 Aug 2022 17:41:59 +0200 [thread overview]
Message-ID: <20220805154231.31257-15-ojeda@kernel.org> (raw)
In-Reply-To: <20220805154231.31257-1-ojeda@kernel.org>
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 3c1853a9d1c0..c414a8d9f1ea 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2246,6 +2246,9 @@ 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
@@ -2372,6 +2375,10 @@ 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,
@@ -2444,6 +2451,12 @@ 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':
--
2.37.1
next prev parent reply other threads:[~2022-08-05 15:46 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-05 15:41 [PATCH v9 00/27] Rust support Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 01/27] kallsyms: use `sizeof` instead of hardcoded size Miguel Ojeda
2022-08-05 16:48 ` Geert Stappers
2022-08-05 18:46 ` Miguel Ojeda
2022-08-05 22:40 ` Konstantin Shelekhin
2022-08-17 19:36 ` Kees Cook
2022-08-18 9:03 ` Konstantin Shelekhin
2022-08-18 16:03 ` Kees Cook
2022-09-27 12:48 ` Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 02/27] kallsyms: avoid hardcoding buffer size Miguel Ojeda
2022-08-17 19:37 ` Kees Cook
2022-08-18 16:50 ` Geert Stappers
2022-08-05 15:41 ` [PATCH v9 03/27] kallsyms: add static relationship between `KSYM_NAME_LEN{,_BUFFER}` Miguel Ojeda
2022-08-17 19:39 ` Kees Cook
2022-08-17 19:50 ` Boqun Feng
2022-08-17 20:31 ` Kees Cook
2022-08-17 20:45 ` Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 04/27] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 05/27] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 06/27] rust: add C helpers Miguel Ojeda
2022-08-17 19:44 ` Kees Cook
2022-08-17 20:22 ` Miguel Ojeda
2022-08-17 20:34 ` Kees Cook
2022-08-17 21:44 ` Miguel Ojeda
2022-08-17 23:56 ` Kees Cook
2022-08-18 16:03 ` Miguel Ojeda
2022-08-18 16:08 ` Kees Cook
2022-08-18 17:01 ` Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 07/27] rust: import upstream `alloc` crate Miguel Ojeda
2022-08-17 20:07 ` Kees Cook
2022-08-17 21:00 ` Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 08/27] rust: adapt `alloc` crate to the kernel Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 09/27] rust: add `compiler_builtins` crate Miguel Ojeda
2022-08-17 20:08 ` Kees Cook
2022-08-22 23:55 ` Nick Desaulniers
2022-08-24 18:38 ` Nick Desaulniers
2022-08-29 17:11 ` Gary Guo
2022-08-05 15:41 ` [PATCH v9 10/27] rust: add `macros` crate Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 11/27] rust: add `bindings` crate Miguel Ojeda
2022-08-05 15:41 ` [PATCH v9 12/27] rust: add `kernel` crate Miguel Ojeda
2022-08-06 10:24 ` Konstantin Shelekhin
2022-08-06 11:22 ` Miguel Ojeda
2022-08-06 12:15 ` Konstantin Shelekhin
2022-08-06 14:57 ` Matthew Wilcox
2022-09-19 14:07 ` Wedson Almeida Filho
2022-09-19 16:09 ` Linus Torvalds
2022-09-19 17:20 ` Linus Torvalds
2022-09-19 18:05 ` Wedson Almeida Filho
2022-09-19 20:42 ` Linus Torvalds
2022-09-19 22:35 ` Wedson Almeida Filho
2022-09-19 23:39 ` Linus Torvalds
2022-09-19 23:50 ` Alex Gaynor
2022-09-19 23:58 ` Linus Torvalds
2022-09-20 0:15 ` Linus Torvalds
2022-09-20 15:55 ` Eric W. Biederman
2022-09-20 22:39 ` Gary Guo
2022-09-21 6:42 ` comex
2022-09-21 14:19 ` Boqun Feng
2022-10-03 2:03 ` comex
2022-09-20 0:40 ` Boqun Feng
2022-10-03 4:17 ` Kyle Strand
2022-09-20 0:41 ` Wedson Almeida Filho
2022-09-21 11:23 ` Konstantin Shelekhin
2022-09-21 11:46 ` Greg KH
2022-08-05 15:41 ` [PATCH v9 13/27] rust: export generated symbols Miguel Ojeda
2022-08-17 20:11 ` Kees Cook
2022-08-05 15:41 ` Miguel Ojeda [this message]
2022-08-05 15:42 ` [PATCH v9 15/27] scripts: checkpatch: diagnose uses of `%pA` in the C side as errors Miguel Ojeda
2022-08-05 15:42 ` [PATCH v9 16/27] scripts: checkpatch: enable language-independent checks for Rust Miguel Ojeda
2022-08-17 20:12 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 17/27] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-08-05 15:42 ` [PATCH v9 18/27] scripts: add `generate_rust_analyzer.py` Miguel Ojeda
2022-08-17 20:13 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 19/27] scripts: add `generate_rust_target.rs` Miguel Ojeda
2022-08-17 20:14 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 20/27] scripts: add `rust_is_available.sh` Miguel Ojeda
2022-08-17 20:18 ` Kees Cook
2022-08-17 20:40 ` Miguel Ojeda
2022-08-22 20:09 ` Nick Desaulniers
2022-08-23 12:12 ` Miguel Ojeda
2022-08-23 12:16 ` Miguel Ojeda
2022-08-05 15:42 ` [PATCH v9 21/27] scripts: add `is_rust_module.sh` Miguel Ojeda
2022-08-17 20:19 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 22/27] rust: add `.rustfmt.toml` Miguel Ojeda
2022-08-17 20:19 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 23/27] Kbuild: add Rust support Miguel Ojeda
2022-08-17 20:26 ` Kees Cook
2022-08-17 20:56 ` Miguel Ojeda
2022-08-22 22:35 ` Nick Desaulniers
2022-09-12 16:07 ` Masahiro Yamada
2022-09-12 16:18 ` Miguel Ojeda
2022-09-13 6:37 ` Masahiro Yamada
2022-08-05 15:42 ` [PATCH v9 24/27] docs: add Rust documentation Miguel Ojeda
2022-08-05 15:42 ` [PATCH v9 25/27] x86: enable initial Rust support Miguel Ojeda
2022-08-17 20:27 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 26/27] samples: add first Rust examples Miguel Ojeda
2022-08-06 13:14 ` Konstantin Shelekhin
2022-08-17 21:02 ` Miguel Ojeda
2022-08-18 9:04 ` Konstantin Shelekhin
2022-08-17 20:28 ` Kees Cook
2022-08-05 15:42 ` [PATCH v9 27/27] MAINTAINERS: Rust Miguel Ojeda
2022-08-17 20:28 ` Kees Cook
2022-08-17 20:43 ` Miguel Ojeda
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