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| author | Will Deacon <will.deacon@arm.com> | 2011-03-04 12:38:54 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-03-09 21:40:18 +0000 |
| commit | 5dab26af1bacad9a7189d904fbc8b4fe8e95dd81 (patch) | |
| tree | 246c70038035ee4a0505f2b043ecb3c73018b01b /arch/arm/include/asm/processor.h | |
| parent | fcbdc5fe6ebe07d502c9b652cb63376bcc4227ac (diff) | |
| download | op-kernel-dev-5dab26af1bacad9a7189d904fbc8b4fe8e95dd81.zip op-kernel-dev-5dab26af1bacad9a7189d904fbc8b4fe8e95dd81.tar.gz | |
ARM: 6784/1: errata: no automatic Store Buffer drain on Cortex-A9
On revisions of the Cortex-A9 prior to r2p0, the Store Buffer does not
have any automatic draining mechanism and therefore a livelock may occur
if an external agent continuously polls a memory location waiting to
observe an update.
This workaround defines cpu_relax() as smp_mb(), preventing correctly
written polling loops from denying visibility of updates to memory.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/processor.h')
| -rw-r--r-- | arch/arm/include/asm/processor.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index 67357ba..7a1f03c 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -95,7 +95,7 @@ extern void release_thread(struct task_struct *); unsigned long get_wchan(struct task_struct *p); -#if __LINUX_ARM_ARCH__ == 6 +#if __LINUX_ARM_ARCH__ == 6 || defined(CONFIG_ARM_ERRATA_754327) #define cpu_relax() smp_mb() #else #define cpu_relax() barrier() |
