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| author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2009-05-25 20:58:00 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-05-28 19:39:27 +0100 |
| commit | bac4e960b5ce2453d862beaf20e59aa68af3b43a (patch) | |
| tree | 69ba3b450a769fa4a613a1f8c4e6454cdcfae5aa /arch/arm/kernel/entry-armv.S | |
| parent | 290815710b51de23f9ed6799d3e0bb762d4f907c (diff) | |
| download | op-kernel-dev-bac4e960b5ce2453d862beaf20e59aa68af3b43a.zip op-kernel-dev-bac4e960b5ce2453d862beaf20e59aa68af3b43a.tar.gz | |
[ARM] barriers: improve xchg, bitops and atomic SMP barriers
Mathieu Desnoyers pointed out that the ARM barriers were lacking:
- cmpxchg, xchg and atomic add return need memory barriers on
architectures which can reorder the relative order in which memory
read/writes can be seen between CPUs, which seems to include recent
ARM architectures. Those barriers are currently missing on ARM.
- test_and_xxx_bit were missing SMP barriers.
So put these barriers in. Provide separate atomic_add/atomic_sub
operations which do not require barriers.
Reported-Reviewed-and-Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/entry-armv.S')
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index d662a2f..83b1da6 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -815,10 +815,7 @@ __kuser_helper_start: */ __kuser_memory_barrier: @ 0xffff0fa0 - -#if __LINUX_ARM_ARCH__ >= 6 && defined(CONFIG_SMP) - mcr p15, 0, r0, c7, c10, 5 @ dmb -#endif + smp_dmb usr_ret lr .align 5 |
