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Commit 85fdbe1b authored by Gunnar Larisch's avatar Gunnar Larisch Committed by Linus Torvalds
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Add cmpxchg_local to ppc 



Add a local processor version of cmpxchg for ppc.

Implements __cmpxchg_u32_local and uses it for 32 bits cmpxchg_local.
It uses the non NMI safe cmpxchg_local_generic for 1, 2 and 8 bytes
cmpxchg_local.

Signed-off-by: default avatarGunnar Larisch <gl@denx.de>
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent df80c8c5

include/asm-ppc/system.h

+49 −2
Original line number Diff line number Diff line
@@ -209,12 +209,34 @@ __cmpxchg_u32(volatile unsigned int *p, unsigned int old, unsigned int new) 
	return prev;

}



static inline unsigned long

__cmpxchg_u32_local(volatile unsigned int *p, unsigned int old,

	unsigned int new)

{

	unsigned int prev;



	__asm__ __volatile__ ("\n\

1:	lwarx	%0,0,%2 \n\

	cmpw	0,%0,%3 \n\

	bne	2f \n"

	PPC405_ERR77(0,%2)

"	stwcx.	%4,0,%2 \n\

	bne-	1b\n"

"2:"

	: "=&r" (prev), "=m" (*p)

	: "r" (p), "r" (old), "r" (new), "m" (*p)

	: "cc", "memory");



	return prev;

}



/* This function doesn't exist, so you'll get a linker error

   if something tries to do an invalid cmpxchg().  */

extern void __cmpxchg_called_with_bad_pointer(void);



static __inline__ unsigned long

__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)

__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,

	unsigned int size)

{

	switch (size) {

	case 4:
@@ -236,6 +258,31 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) 
				    (unsigned long)_n_, sizeof(*(ptr))); \

  })



#include <asm-generic/cmpxchg-local.h>



static inline unsigned long __cmpxchg_local(volatile void *ptr,

				      unsigned long old,

				      unsigned long new, int size)

{

	switch (size) {

	case 4:

		return __cmpxchg_u32_local(ptr, old, new);

	default:

		return __cmpxchg_local_generic(ptr, old, new, size);

	}



	return old;

}



/*

 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make

 * them available.

 */

#define cmpxchg_local(ptr, o, n)				  	\

	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\

			(unsigned long)(n), sizeof(*(ptr))))

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



#define arch_align_stack(x) (x)



#endif /* __KERNEL__ */