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| author | Catalin Marinas <catalin.marinas@arm.com> | 2013-05-31 16:30:58 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-01-09 12:24:20 -0800 |
| commit | 42b5bb47a62b7b2d8cd0b9af58f914c5e83ef76e (patch) | |
| tree | 1a57e454dce9bd9243dcbe832b94258e6abd3fa1 | |
| parent | 11b81802921618b02122855db021a63df7d9fd49 (diff) | |
| download | linux-3.10-42b5bb47a62b7b2d8cd0b9af58f914c5e83ef76e.tar.gz linux-3.10-42b5bb47a62b7b2d8cd0b9af58f914c5e83ef76e.tar.bz2 linux-3.10-42b5bb47a62b7b2d8cd0b9af58f914c5e83ef76e.zip | |
arm64: spinlock: retry trylock operation if strex fails on free lock
commit 4ecf7ccb1973fd826456b6ab1e6dfafe9023c753 upstream.
An exclusive store instruction may fail for reasons other than lock
contention (e.g. a cache eviction during the critical section) so, in
line with other architectures using similar exclusive instructions
(alpha, mips, powerpc), retry the trylock operation if the lock appears
to be free but the strex reported failure.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Tony Thompson <anthony.thompson@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/include/asm/spinlock.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index 7065e920149..0defa0728a9 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -59,9 +59,10 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) unsigned int tmp; asm volatile( - " ldaxr %w0, %1\n" + "2: ldaxr %w0, %1\n" " cbnz %w0, 1f\n" " stxr %w0, %w2, %1\n" + " cbnz %w0, 2b\n" "1:\n" : "=&r" (tmp), "+Q" (lock->lock) : "r" (1) |