release/src-rt-6.x.4708/linux/linux-2.6.36/include/asm-generic/cmpxchg-local.h

   1 /* Modified by Broadcom Corp. Portions Copyright (c) Broadcom Corp, 2012. */
   2 #ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
   3 #define __ASM_GENERIC_CMPXCHG_LOCAL_H
   4
   5 #include <linux/types.h>
   6
   7 #if defined(CONFIG_BUZZZ_FUNC)
   8 #ifndef __always_inline__
   9 #define __always_inline__ inline __attribute__((always_inline)) __attribute__((no_instrument_function))
  10 #endif
  11 #else   /* !CONFIG_BUZZZ_FUNC */
  12 #ifndef __always_inline__
  13 #define __always_inline__ inline
  14 #endif
  15 #endif  /* !CONFIG_BUZZZ_FUNC */
  16
  17 extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
  18
  19 /*
  20  * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
  21  * long parameter, supporting various types of architectures.
  22  */
  23 static __always_inline__ unsigned long __cmpxchg_local_generic(volatile void *ptr,
  24                 unsigned long old, unsigned long new, int size)
  25 {
  26         unsigned long flags, prev;
  27
  28         /*
  29          * Sanity checking, compile-time.
  30          */
  31         if (size == 8 && sizeof(unsigned long) != 8)
  32                 wrong_size_cmpxchg(ptr);
  33
  34         local_irq_save(flags);
  35         switch (size) {
  36         case 1: prev = *(u8 *)ptr;
  37                 if (prev == old)
  38                         *(u8 *)ptr = (u8)new;
  39                 break;
  40         case 2: prev = *(u16 *)ptr;
  41                 if (prev == old)
  42                         *(u16 *)ptr = (u16)new;
  43                 break;
  44         case 4: prev = *(u32 *)ptr;
  45                 if (prev == old)
  46                         *(u32 *)ptr = (u32)new;
  47                 break;
  48         case 8: prev = *(u64 *)ptr;
  49                 if (prev == old)
  50                         *(u64 *)ptr = (u64)new;
  51                 break;
  52         default:
  53                 wrong_size_cmpxchg(ptr);
  54         }
  55         local_irq_restore(flags);
  56         return prev;
  57 }
  58
  59 /*
  60  * Generic version of __cmpxchg64_local. Takes an u64 parameter.
  61  */
  62 static __always_inline__ u64 __cmpxchg64_local_generic(volatile void *ptr,
  63                 u64 old, u64 new)
  64 {
  65         u64 prev;
  66         unsigned long flags;
  67
  68         local_irq_save(flags);
  69         prev = *(u64 *)ptr;
  70         if (prev == old)
  71                 *(u64 *)ptr = new;
  72         local_irq_restore(flags);
  73         return prev;
  74 }
  75
  76 #endif