kernel/arch/ia64/include/uapi/asm/cmpxchg.h

   1 #ifndef _ASM_IA64_CMPXCHG_H
   2 #define _ASM_IA64_CMPXCHG_H
   3
   4 /*
   5  * Compare/Exchange, forked from asm/intrinsics.h
   6  * which was:
   7  *
   8  *      Copyright (C) 2002-2003 Hewlett-Packard Co
   9  *      David Mosberger-Tang <davidm@hpl.hp.com>
  10  */
  11
  12 #ifndef __ASSEMBLY__
  13
  14 #include <linux/types.h>
  15 /* include compiler specific intrinsics */
  16 #include <asm/ia64regs.h>
  17 #ifdef __INTEL_COMPILER
  18 # include <asm/intel_intrin.h>
  19 #else
  20 # include <asm/gcc_intrin.h>
  21 #endif
  22
  23 /*
  24  * This function doesn't exist, so you'll get a linker error if
  25  * something tries to do an invalid xchg().
  26  */
  27 extern void ia64_xchg_called_with_bad_pointer(void);
  28
  29 #define __xchg(x, ptr, size)                                            \
  30 ({                                                                      \
  31         unsigned long __xchg_result;                                    \
  32                                                                         \
  33         switch (size) {                                                 \
  34         case 1:                                                         \
  35                 __xchg_result = ia64_xchg1((__u8 *)ptr, x);             \
  36                 break;                                                  \
  37                                                                         \
  38         case 2:                                                         \
  39                 __xchg_result = ia64_xchg2((__u16 *)ptr, x);            \
  40                 break;                                                  \
  41                                                                         \
  42         case 4:                                                         \
  43                 __xchg_result = ia64_xchg4((__u32 *)ptr, x);            \
  44                 break;                                                  \
  45                                                                         \
  46         case 8:                                                         \
  47                 __xchg_result = ia64_xchg8((__u64 *)ptr, x);            \
  48                 break;                                                  \
  49         default:                                                        \
  50                 ia64_xchg_called_with_bad_pointer();                    \
  51         }                                                               \
  52         __xchg_result;                                                  \
  53 })
  54
  55 #define xchg(ptr, x)                                                    \
  56 ((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
  57
  58 /*
  59  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  60  * store NEW in MEM.  Return the initial value in MEM.  Success is
  61  * indicated by comparing RETURN with OLD.
  62  */
  63
  64 /*
  65  * This function doesn't exist, so you'll get a linker error
  66  * if something tries to do an invalid cmpxchg().
  67  */
  68 extern long ia64_cmpxchg_called_with_bad_pointer(void);
  69
  70 #define ia64_cmpxchg(sem, ptr, old, new, size)                          \
  71 ({                                                                      \
  72         __u64 _o_, _r_;                                                 \
  73                                                                         \
  74         switch (size) {                                                 \
  75         case 1:                                                         \
  76                 _o_ = (__u8) (long) (old);                              \
  77                 break;                                                  \
  78         case 2:                                                         \
  79                 _o_ = (__u16) (long) (old);                             \
  80                 break;                                                  \
  81         case 4:                                                         \
  82                 _o_ = (__u32) (long) (old);                             \
  83                 break;                                                  \
  84         case 8:                                                         \
  85                 _o_ = (__u64) (long) (old);                             \
  86                 break;                                                  \
  87         default:                                                        \
  88                 break;                                                  \
  89         }                                                               \
  90         switch (size) {                                                 \
  91         case 1:                                                         \
  92                 _r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_);      \
  93                 break;                                                  \
  94                                                                         \
  95         case 2:                                                         \
  96                 _r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_);     \
  97                 break;                                                  \
  98                                                                         \
  99         case 4:                                                         \
 100                 _r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_);     \
 101                 break;                                                  \
 102                                                                         \
 103         case 8:                                                         \
 104                 _r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_);     \
 105                 break;                                                  \
 106                                                                         \
 107         default:                                                        \
 108                 _r_ = ia64_cmpxchg_called_with_bad_pointer();           \
 109                 break;                                                  \
 110         }                                                               \
 111         (__typeof__(old)) _r_;                                          \
 112 })
 113
 114 #define cmpxchg_acq(ptr, o, n)  \
 115         ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
 116 #define cmpxchg_rel(ptr, o, n)  \
 117         ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
 118
 119 /*
 120  * Worse still - early processor implementations actually just ignored
 121  * the acquire/release and did a full fence all the time.  Unfortunately
 122  * this meant a lot of badly written code that used .acq when they really
 123  * wanted .rel became legacy out in the wild - so when we made a cpu
 124  * that strictly did the .acq or .rel ... all that code started breaking - so
 125  * we had to back-pedal and keep the "legacy" behavior of a full fence :-(
 126  */
 127
 128 /* for compatibility with other platforms: */
 129 #define cmpxchg(ptr, o, n)      cmpxchg_acq((ptr), (o), (n))
 130 #define cmpxchg64(ptr, o, n)    cmpxchg_acq((ptr), (o), (n))
 131
 132 #define cmpxchg_local           cmpxchg
 133 #define cmpxchg64_local         cmpxchg64
 134
 135 #ifdef CONFIG_IA64_DEBUG_CMPXCHG
 136 # define CMPXCHG_BUGCHECK_DECL  int _cmpxchg_bugcheck_count = 128;
 137 # define CMPXCHG_BUGCHECK(v)                                            \
 138 do {                                                                    \
 139         if (_cmpxchg_bugcheck_count-- <= 0) {                           \
 140                 void *ip;                                               \
 141                 extern int printk(const char *fmt, ...);                \
 142                 ip = (void *) ia64_getreg(_IA64_REG_IP);                \
 143                 printk("CMPXCHG_BUGCHECK: stuck at %p on word %p\n", ip, (v));\
 144                 break;                                                  \
 145         }                                                               \
 146 } while (0)
 147 #else /* !CONFIG_IA64_DEBUG_CMPXCHG */
 148 # define CMPXCHG_BUGCHECK_DECL
 149 # define CMPXCHG_BUGCHECK(v)
 150 #endif /* !CONFIG_IA64_DEBUG_CMPXCHG */
 151
 152 #endif /* !__ASSEMBLY__ */
 153
 154 #endif /* _ASM_IA64_CMPXCHG_H */