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    Subject[patch 23/28] Add cmpxchg_local to sh, use generic cmpxchg() instead of cmpxchg_u32
    Use the new generic cmpxchg_local (disables interrupt). Also use the generic
    cmpxchg as fallback if SMP is not set.

    Since cmpxchg_u32 is _exactly_ the cmpxchg_local generic implementation, remove
    it and use the generic version instead.

    Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
    CC: clameter@sgi.com
    CC: lethal@linux-sh.org
    ---
    include/asm-sh/system.h | 52 ++++++++++++------------------------------------
    1 file changed, 14 insertions(+), 38 deletions(-)

    Index: linux-2.6-lttng/include/asm-sh/system.h
    ===================================================================
    --- linux-2.6-lttng.orig/include/asm-sh/system.h 2007-10-31 17:32:43.000000000 -0400
    +++ linux-2.6-lttng/include/asm-sh/system.h 2007-10-31 18:27:24.000000000 -0400
    @@ -199,47 +199,23 @@ extern void __xchg_called_with_bad_point
    __xchg__res; \
    })

    -#define xchg(ptr,x) \
    - ((__typeof__(*(ptr)))__xchg((ptr),(unsigned long)(x), sizeof(*(ptr))))
    +#define xchg(ptr, x) \
    + ((__typeof__(*(ptr)))__xchg((ptr), (unsigned long)(x), sizeof(*(ptr))))

    -static inline unsigned long __cmpxchg_u32(volatile int * m, unsigned long old,
    - unsigned long new)
    -{
    - __u32 retval;
    - unsigned long flags;
    -
    - local_irq_save(flags);
    - retval = *m;
    - if (retval == old)
    - *m = new;
    - local_irq_restore(flags); /* implies memory barrier */
    - return retval;
    -}
    -
    -/* 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);
    -
    -#define __HAVE_ARCH_CMPXCHG 1
    +#include <asm-generic/cmpxchg-local.h>

    -static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
    - unsigned long new, int size)
    -{
    - switch (size) {
    - case 4:
    - return __cmpxchg_u32(ptr, old, new);
    - }
    - __cmpxchg_called_with_bad_pointer();
    - 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_generic((ptr), (unsigned long)(o),\
    + (unsigned long)(n), sizeof(*(ptr))))
    +#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))

    -#define cmpxchg(ptr,o,n) \
    - ({ \
    - __typeof__(*(ptr)) _o_ = (o); \
    - __typeof__(*(ptr)) _n_ = (n); \
    - (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
    - (unsigned long)_n_, sizeof(*(ptr))); \
    - })
    +#ifndef CONFIG_SMP
    +#include <asm-generic/cmpxchg.h>
    +#endif

    extern void die(const char *str, struct pt_regs *regs, long err) __attribute__ ((noreturn));

    --
    Mathieu Desnoyers
    Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
    OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
    -
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