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Commit 9623b373 authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
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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: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 5bfe8cb6

include/asm-arm/system.h

+19 −21
Original line number Diff line number Diff line
@@ -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 mb()			barrier()

#define rmb()			barrier()

#define wmb()			barrier()

#define read_barrier_depends()	do { } while(0)

#define set_mb(var, value)  do { var = value; mb(); } 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