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    Subject[patch 14/28] New cmpxchg_local (optimized for UP case) for m32r
    Add __xchg_local, xchg_local (define), __cmpxchg_local_u32, __cmpxchg_local,
    cmpxchg_local(macro).

    cmpxchg_local and cmpxchg64_local will use the architecture specific
    __cmpxchg_local_u32 for 32 bits arguments, and use the generic
    __cmpxchg_local_generic for 8, 16 and 64 bits arguments.

    Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
    Acked-by: Hirokazu Takata <takata@linux-m32r.org>
    CC: clameter@sgi.com
    CC: linux-m32r@ml.linux-m32r.org
    ---
    include/asm-m32r/system.h | 103 +++++++++++++++++++++++++++++++++++++++++++---
    1 file changed, 97 insertions(+), 6 deletions(-)

    Index: linux-2.6-lttng/include/asm-m32r/system.h
    ===================================================================
    --- linux-2.6-lttng.orig/include/asm-m32r/system.h 2007-08-07 14:31:52.000000000 -0400
    +++ linux-2.6-lttng/include/asm-m32r/system.h 2007-08-07 14:55:02.000000000 -0400
    @@ -123,6 +123,9 @@ static inline void local_irq_disable(voi

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

    #ifdef CONFIG_SMP
    extern void __xchg_called_with_bad_pointer(void);
    @@ -196,6 +199,42 @@ __xchg(unsigned long x, volatile void *
    return (tmp);
    }

    +static __always_inline unsigned long
    +__xchg_local(unsigned long x, volatile void * ptr, int size)
    +{
    + unsigned long flags;
    + unsigned long tmp = 0;
    +
    + local_irq_save(flags);
    +
    + switch (size) {
    + case 1:
    + __asm__ __volatile__ (
    + "ldb %0, @%2 \n\t"
    + "stb %1, @%2 \n\t"
    + : "=&r" (tmp) : "r" (x), "r" (ptr) : "memory");
    + break;
    + case 2:
    + __asm__ __volatile__ (
    + "ldh %0, @%2 \n\t"
    + "sth %1, @%2 \n\t"
    + : "=&r" (tmp) : "r" (x), "r" (ptr) : "memory");
    + break;
    + case 4:
    + __asm__ __volatile__ (
    + "ld %0, @%2 \n\t"
    + "st %1, @%2 \n\t"
    + : "=&r" (tmp) : "r" (x), "r" (ptr) : "memory");
    + break;
    + default:
    + __xchg_called_with_bad_pointer();
    + }
    +
    + local_irq_restore(flags);
    +
    + return (tmp);
    +}
    +
    #define __HAVE_ARCH_CMPXCHG 1

    static inline unsigned long
    @@ -228,6 +267,37 @@ __cmpxchg_u32(volatile unsigned int *p,
    return retval;
    }

    +static inline unsigned long
    +__cmpxchg_local_u32(volatile unsigned int *p, unsigned int old,
    + unsigned int new)
    +{
    + unsigned long flags;
    + unsigned int retval;
    +
    + local_irq_save(flags);
    + __asm__ __volatile__ (
    + DCACHE_CLEAR("%0", "r4", "%1")
    + "ld %0, @%1; \n"
    + " bne %0, %2, 1f; \n"
    + "st %3, @%1; \n"
    + " bra 2f; \n"
    + " .fillinsn \n"
    + "1:"
    + "st %0, @%1; \n"
    + " .fillinsn \n"
    + "2:"
    + : "=&r" (retval)
    + : "r" (p), "r" (old), "r" (new)
    + : "cbit", "memory"
    +#ifdef CONFIG_CHIP_M32700_TS1
    + , "r4"
    +#endif /* CONFIG_CHIP_M32700_TS1 */
    + );
    + local_irq_restore(flags);
    +
    + 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);
    @@ -248,12 +318,33 @@ __cmpxchg(volatile void *ptr, unsigned l
    }

    #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))); \
    - })
    + (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)(o), \
    + (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_local_u32(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))

    #endif /* __KERNEL__ */

    --
    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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