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Commit 4ed67a53 authored by Russell King's avatar Russell King
Browse files

ARM: v6k: select cmpxchg code sequences according to V6 variants 



If CONFIG_CPU_V6 is enabled, we must avoid the byte/halfword/doubleword
exclusive operations, which aren't implemented before V6K.  Use the
generic versions (or omit them) instead.

If CONFIG_CPU_V6 is not set, but CONFIG_CPU_32v6K is enabled, we have
the K extnesions, so use these new instructions.

Acked-by: default avatarTony Lindgren <tony@atomide.com>
Tested-by: default avatarSourav Poddar <sourav.poddar@ti.com>
Tested-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 7db44c75

arch/arm/include/asm/system.h

+9 −8
Original line number Diff line number Diff line
@@ -347,6 +347,7 @@ void cpu_idle_wait(void); 
#include <asm-generic/cmpxchg-local.h>



#if __LINUX_ARM_ARCH__ < 6

/* min ARCH < ARMv6 */



#ifdef CONFIG_SMP

#error "SMP is not supported on this platform"
@@ -365,7 +366,7 @@ void cpu_idle_wait(void); 
#include <asm-generic/cmpxchg.h>

#endif



#else	/* __LINUX_ARM_ARCH__ >= 6 */

#else	/* min ARCH >= ARMv6 */



extern void __bad_cmpxchg(volatile void *ptr, int size);
@@ -379,7 +380,7 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 
	unsigned long oldval, res;



	switch (size) {

#ifdef CONFIG_CPU_32v6K

#ifndef CONFIG_CPU_V6	/* min ARCH >= ARMv6K */

	case 1:

		do {

			asm volatile("@ __cmpxchg1\n"
@@ -404,7 +405,7 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 
				: "memory", "cc");

		} while (res);

		break;

#endif /* CONFIG_CPU_32v6K */

#endif

	case 4:

		do {

			asm volatile("@ __cmpxchg4\n"
@@ -450,12 +451,12 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr, 
	unsigned long ret;



	switch (size) {

#ifndef CONFIG_CPU_32v6K

#ifdef CONFIG_CPU_V6	/* min ARCH == ARMv6 */

	case 1:

	case 2:

		ret = __cmpxchg_local_generic(ptr, old, new, size);

		break;

#endif	/* !CONFIG_CPU_32v6K */

#endif

	default:

		ret = __cmpxchg(ptr, old, new, size);

	}
@@ -469,7 +470,7 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr, 
				       (unsigned long)(n),		\

				       sizeof(*(ptr))))



#ifdef CONFIG_CPU_32v6K

#ifndef CONFIG_CPU_V6	/* min ARCH >= ARMv6K */



/*

 * Note : ARMv7-M (currently unsupported by Linux) does not support
@@ -524,11 +525,11 @@ static inline unsigned long long __cmpxchg64_mb(volatile void *ptr, 
					 (unsigned long long)(o),	\

					 (unsigned long long)(n)))



#else	/* !CONFIG_CPU_32v6K */

#else /* min ARCH = ARMv6 */



#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))



#endif	/* CONFIG_CPU_32v6K */

#endif



#endif	/* __LINUX_ARM_ARCH__ >= 6 */