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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: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Michael Frysinger <michael.frysinger@analog.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -183,55 +183,20 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
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return tmp;
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}
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#include <asm-generic/cmpxchg-local.h>
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/*
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* Atomic compare and exchange. Compare OLD with MEM, if identical,
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* store NEW in MEM. Return the initial value in MEM. Success is
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* indicated by comparing RETURN with OLD.
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* cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
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* them available.
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*/
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static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
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unsigned long new, int size)
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{
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unsigned long tmp = 0;
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unsigned long flags = 0;
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#define cmpxchg_local(ptr, o, n) \
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((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
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(unsigned long)(n), sizeof(*(ptr))))
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#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
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local_irq_save(flags);
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switch (size) {
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case 1:
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__asm__ __volatile__
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("%0 = b%3 (z);\n\t"
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"CC = %1 == %0;\n\t"
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"IF !CC JUMP 1f;\n\t"
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"b%3 = %2;\n\t"
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"1:\n\t"
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: "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");
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break;
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case 2:
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__asm__ __volatile__
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("%0 = w%3 (z);\n\t"
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"CC = %1 == %0;\n\t"
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"IF !CC JUMP 1f;\n\t"
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"w%3 = %2;\n\t"
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"1:\n\t"
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: "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");
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break;
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case 4:
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__asm__ __volatile__
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("%0 = %3;\n\t"
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"CC = %1 == %0;\n\t"
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"IF !CC JUMP 1f;\n\t"
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"%3 = %2;\n\t"
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"1:\n\t"
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: "=&d" (tmp) : "d" (old), "d" (new), "m" (*__xg(ptr)) : "memory");
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break;
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}
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local_irq_restore(flags);
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return tmp;
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}
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#define cmpxchg(ptr,o,n)\
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((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
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(unsigned long)(n),sizeof(*(ptr))))
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#ifndef CONFIG_SMP
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#include <asm-generic/cmpxchg.h>
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#endif
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#define prepare_to_switch() do { } while(0)
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