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| author | Will Deacon <will@kernel.org> | 2019-10-15 17:30:47 -0700 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-07-21 10:50:35 +0100 |
| commit | b78b331a3f5c0773171dadd6bbfa2a2242b45604 (patch) | |
| tree | 6e9a048a1026a379b549760c863e636539e10863 /include/asm-generic/rwonce.h | |
| parent | e506ea451254ab17e0bf918ca36232fec2a9b10c (diff) | |
| download | lwn-b78b331a3f5c0773171dadd6bbfa2a2242b45604.tar.gz lwn-b78b331a3f5c0773171dadd6bbfa2a2242b45604.zip | |
asm/rwonce: Allow __READ_ONCE to be overridden by the architecture
The meat and potatoes of READ_ONCE() is defined by the __READ_ONCE()
macro, which uses a volatile casts in an attempt to avoid tearing of
byte, halfword, word and double-word accesses. Allow this to be
overridden by the architecture code in the case that things like memory
barriers are also required.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'include/asm-generic/rwonce.h')
| -rw-r--r-- | include/asm-generic/rwonce.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-generic/rwonce.h b/include/asm-generic/rwonce.h index 87584379da43..04586b55a7c2 100644 --- a/include/asm-generic/rwonce.h +++ b/include/asm-generic/rwonce.h @@ -43,7 +43,9 @@ * atomicity or dependency ordering guarantees. Note that this may result * in tears! */ +#ifndef __READ_ONCE #define __READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x)) +#endif #define __READ_ONCE_SCALAR(x) \ ({ \ |