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Commit 10b88270 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Linus Torvalds
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Add cmpxchg_local to blackfin, replace __cmpxchg by generic cmpxchg 



Use the new generic cmpxchg_local (disables interrupt). Also use the generic
cmpxchg as fallback if SMP is not set since nobody seems to know why __cmpxchg
has been implemented in assembly in the first place thather than in plain C.

Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Michael Frysinger <michael.frysinger@analog.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5e86c11d

include/asm-blackfin/system.h

+11 −46
Original line number Diff line number Diff line
@@ -183,55 +183,20 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, 
	return tmp;

}



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



/*

 * Atomic compare and exchange.  Compare OLD with MEM, if identical,

 * store NEW in MEM.  Return the initial value in MEM.  Success is

 * indicated by comparing RETURN with OLD.

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

 * them available.

 */

static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,

				      unsigned long new, int size)

{

	unsigned long tmp = 0;

	unsigned long flags = 0;



	local_irq_save(flags);



	switch (size) {

	case 1:

		__asm__ __volatile__

			("%0 = b%3 (z);\n\t"

			 "CC = %1 == %0;\n\t"

			 "IF !CC JUMP 1f;\n\t"

			 "b%3 = %2;\n\t"

			 "1:\n\t"

			 : "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");

		break;

	case 2:

		__asm__ __volatile__

			("%0 = w%3 (z);\n\t"

			 "CC = %1 == %0;\n\t"

			 "IF !CC JUMP 1f;\n\t"

			 "w%3 = %2;\n\t"

			 "1:\n\t"

			 : "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");

		break;

	case 4:

		__asm__ __volatile__

			("%0 = %3;\n\t"

			 "CC = %1 == %0;\n\t"

			 "IF !CC JUMP 1f;\n\t"

			 "%3 = %2;\n\t"

			 "1:\n\t"

			 : "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");

		break;

	}

	local_irq_restore(flags);

	return tmp;

}



#define cmpxchg(ptr,o,n)\

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

#define cmpxchg_local(ptr, o, n)				  	       \

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

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

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



#ifndef CONFIG_SMP

#include <asm-generic/cmpxchg.h>

#endif



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