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[ARM] 4241/1: Define mb() as compiler barrier on a uniprocessor system 

Currently, the mb() is defined as a DMB operation on ARMv6, even for
UP systems. This patch defines mb() as a compiler barrier only. For
the SMP case, the smp_* variants should be used anyway and the patch
defines them as DMB.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas 2007-02-28 12:30:38 +01:00 committed by Russell King
parent 5bfe8cb621
commit 9623b3732d
1 changed files with 19 additions and 21 deletions
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40
include/asm-arm/system.h
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@ -167,11 +167,25 @@ extern unsigned int user_debug;
: : "r" (0) : "memory")
#define dmb() __asm__ __volatile__ ("" : : : "memory")
#endif
#define mb() dmb()
#define rmb() mb()
#define wmb() mb()
#define read_barrier_depends() do { } while(0)
#define set_mb(var, value) do { var = value; mb(); } while (0)
#define mb() barrier()
#define rmb() barrier()
#define wmb() barrier()
#define read_barrier_depends() do { } while(0)
#ifdef CONFIG_SMP
#define smp_mb() dmb()
#define smp_rmb() dmb()
#define smp_wmb() dmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() read_barrier_depends()
#endif /* CONFIG_SMP */
#define set_mb(var, value) do { var = value; smp_mb(); } while (0)
#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
@ -243,22 +257,6 @@ static inline void sched_cacheflush(void)
{
}
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() do { } while(0)
#endif /* CONFIG_SMP */
#if defined(CONFIG_CPU_SA1100) || defined(CONFIG_CPU_SA110)
/*
* On the StrongARM, "swp" is terminally broken since it bypasses the