From: "tip-bot2 for Marco Elver" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Marco Elver <elver@google.com>, Borislav Petkov <bp@suse.de>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Will Deacon <will@kernel.org>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: locking/kcsan] compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE()
Date: Fri, 22 May 2020 16:08:46 -0000 [thread overview]
Message-ID: <159016372659.17951.9279233583704092655.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200521142047.169334-9-elver@google.com>
The following commit has been merged into the locking/kcsan branch of tip:
Commit-ID: 777f73c4e79106d45b304f6af0d31917864dbdf1
Gitweb: https://git.kernel.org/tip/777f73c4e79106d45b304f6af0d31917864dbdf1
Author: Marco Elver <elver@google.com>
AuthorDate: Thu, 21 May 2020 16:20:44 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Fri, 22 May 2020 15:19:53 +02:00
compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE()
The volatile accesses no longer need to be wrapped in data_race()
because compilers that emit instrumentation distinguishing volatile
accesses are required for KCSAN.
Consequently, the explicit kcsan_check_atomic*() are no longer required
either since the compiler emits instrumentation distinguishing the
volatile accesses.
Finally, simplify __READ_ONCE_SCALAR() and remove __WRITE_ONCE_SCALAR().
[ bp: Convert commit message to passive voice. ]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20200521142047.169334-9-elver@google.com
---
include/linux/compiler.h | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 17c98b2..7444f02 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -228,9 +228,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#define __READ_ONCE_SCALAR(x) \
({ \
- typeof(x) *__xp = &(x); \
- __unqual_scalar_typeof(x) __x = data_race(__READ_ONCE(*__xp)); \
- kcsan_check_atomic_read(__xp, sizeof(*__xp)); \
+ __unqual_scalar_typeof(x) __x = __READ_ONCE(x); \
smp_read_barrier_depends(); \
(typeof(x))__x; \
})
@@ -246,17 +244,10 @@ do { \
*(volatile typeof(x) *)&(x) = (val); \
} while (0)
-#define __WRITE_ONCE_SCALAR(x, val) \
-do { \
- typeof(x) *__xp = &(x); \
- kcsan_check_atomic_write(__xp, sizeof(*__xp)); \
- data_race(({ __WRITE_ONCE(*__xp, val); 0; })); \
-} while (0)
-
#define WRITE_ONCE(x, val) \
do { \
compiletime_assert_rwonce_type(x); \
- __WRITE_ONCE_SCALAR(x, val); \
+ __WRITE_ONCE(x, val); \
} while (0)
#ifdef CONFIG_KASAN
next prev parent reply other threads:[~2020-05-22 16:08 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-21 14:20 [PATCH -tip v3 00/11] Fix KCSAN for new ONCE (require Clang 11) Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 01/11] ubsan, kcsan: don't combine sanitizer with kcov on clang Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 02/11] kcsan: Avoid inserting __tsan_func_entry/exit if possible Marco Elver
2020-05-22 16:08 ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 03/11] kcsan: Support distinguishing volatile accesses Marco Elver
2020-05-22 10:26 ` Borislav Petkov
2020-05-22 10:34 ` Marco Elver
2020-05-22 10:47 ` Borislav Petkov
2020-05-22 16:08 ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 04/11] kcsan: Pass option tsan-instrument-read-before-write to Clang Marco Elver
2020-05-22 16:08 ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 05/11] kcsan: Remove 'noinline' from __no_kcsan_or_inline Marco Elver
2020-05-29 17:07 ` Peter Zijlstra
2020-05-29 18:36 ` Marco Elver
2020-05-29 18:59 ` Peter Zijlstra
2020-05-21 14:20 ` [PATCH -tip v3 06/11] kcsan: Restrict supported compilers Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 07/11] kcsan: Update Documentation to change " Marco Elver
2020-05-22 16:08 ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 08/11] READ_ONCE, WRITE_ONCE: Remove data_race() and unnecessary checks Marco Elver
2020-05-22 16:08 ` tip-bot2 for Marco Elver [this message]
2020-05-21 14:20 ` [PATCH -tip v3 09/11] data_race: Avoid nested statement expression Marco Elver
2020-05-21 20:21 ` Nick Desaulniers
2020-05-26 10:42 ` Arnd Bergmann
2020-05-26 12:02 ` Will Deacon
2020-05-26 12:19 ` Arnd Bergmann
2020-05-26 13:12 ` Marco Elver
2020-05-26 17:33 ` Marco Elver
2020-05-26 19:00 ` Arnd Bergmann
2020-05-26 23:10 ` Arnd Bergmann
2020-05-27 7:22 ` Will Deacon
2020-05-27 7:44 ` Marco Elver
2020-05-27 9:26 ` Arnd Bergmann
2020-05-28 12:53 ` Stephen Rothwell
2020-05-26 21:36 ` Peter Zijlstra
2020-05-21 14:20 ` [PATCH -tip v3 10/11] compiler.h: Move function attributes to compiler_types.h Marco Elver
2020-05-22 16:08 ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 11/11] compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining Marco Elver
2020-05-22 16:08 ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-22 11:35 ` [PATCH -tip v3 00/11] Fix KCSAN for new ONCE (require Clang 11) Peter Zijlstra
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