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| author | Uros Bizjak <ubizjak@gmail.com> | 2023-09-25 16:50:23 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-10-09 18:14:15 +0200 |
| commit | e01cc1e8c2ad73cebb980878ede5584e0f2688f7 (patch) | |
| tree | ee93283bb168d049096a9415bfee8efd99efabe1 /include/linux/atomic | |
| parent | fdb8b7a1af31d69ee1c8ddc02926cb409eaaecc3 (diff) | |
| download | lwn-e01cc1e8c2ad73cebb980878ede5584e0f2688f7.tar.gz lwn-e01cc1e8c2ad73cebb980878ede5584e0f2688f7.zip | |
locking/atomic: Add generic support for sync_try_cmpxchg() and its fallback
Provide the generic sync_try_cmpxchg() function from the
raw_ prefixed version, also adding explicit instrumentation.
The patch amends existing scripts to generate sync_try_cmpxchg()
locking primitive and its raw_sync_try_cmpxchg() fallback, while
leaving existing macros from the try_cmpxchg() family unchanged.
The target can define its own arch_sync_try_cmpxchg() to override the
generic version of raw_sync_try_cmpxchg(). This allows the target
to generate more optimal assembly than the generic version.
Additionally, the patch renames two scripts to better reflect
whet they really do.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'include/linux/atomic')
| -rw-r--r-- | include/linux/atomic/atomic-arch-fallback.h | 15 | ||||
| -rw-r--r-- | include/linux/atomic/atomic-instrumented.h | 10 |
2 files changed, 23 insertions, 2 deletions
diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h index b83ef19da13d..5e95faa959c4 100644 --- a/include/linux/atomic/atomic-arch-fallback.h +++ b/include/linux/atomic/atomic-arch-fallback.h @@ -428,6 +428,19 @@ extern void raw_cmpxchg128_relaxed_not_implemented(void); #define raw_sync_cmpxchg arch_sync_cmpxchg +#ifdef arch_sync_try_cmpxchg +#define raw_sync_try_cmpxchg arch_sync_try_cmpxchg +#else +#define raw_sync_try_cmpxchg(_ptr, _oldp, _new) \ +({ \ + typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + ___r = raw_sync_cmpxchg((_ptr), ___o, (_new)); \ + if (unlikely(___r != ___o)) \ + *___op = ___r; \ + likely(___r == ___o); \ +}) +#endif + /** * raw_atomic_read() - atomic load with relaxed ordering * @v: pointer to atomic_t @@ -4649,4 +4662,4 @@ raw_atomic64_dec_if_positive(atomic64_t *v) } #endif /* _LINUX_ATOMIC_FALLBACK_H */ -// 2fdd6702823fa842f9cea57a002e6e4476ae780c +// eec048affea735b8464f58e6d96992101f8f85f1 diff --git a/include/linux/atomic/atomic-instrumented.h b/include/linux/atomic/atomic-instrumented.h index d401b406ef7c..54d7bbe0aeaa 100644 --- a/include/linux/atomic/atomic-instrumented.h +++ b/include/linux/atomic/atomic-instrumented.h @@ -4998,6 +4998,14 @@ atomic_long_dec_if_positive(atomic_long_t *v) raw_try_cmpxchg128_local(__ai_ptr, __ai_oldp, __VA_ARGS__); \ }) +#define sync_try_cmpxchg(ptr, ...) \ +({ \ + typeof(ptr) __ai_ptr = (ptr); \ + kcsan_mb(); \ + instrument_atomic_read_write(__ai_ptr, sizeof(*__ai_ptr)); \ + raw_sync_try_cmpxchg(__ai_ptr, __VA_ARGS__); \ +}) + #endif /* _LINUX_ATOMIC_INSTRUMENTED_H */ -// 1568f875fef72097413caab8339120c065a39aa4 +// 2cc4bc990fef44d3836ec108f11b610f3f438184 |