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 #define __HAVE_ARCH_CMPXCHG 1
  65
  66 /*
  67  * This function doesn't exist, so you'll get a linker error
  68  * if something tries to do an invalid cmpxchg().
  69  */
  70 extern long ia64_cmpxchg_called_with_bad_pointer(void);
  71
  72 #define ia64_cmpxchg(sem, ptr, old, new, size)                          \
  73 ({                                                                      \
  74         __u64 _o_, _r_;                                                 \
  75                                                                         \
  76         switch (size) {                                                 \
  77         case 1:                                                         \
  78                 _o_ = (__u8) (long) (old);                              \
  79                 break;                                                  \
  80         case 2:                                                         \
  81                 _o_ = (__u16) (long) (old);                             \
  82                 break;                                                  \
  83         case 4:                                                         \
  84                 _o_ = (__u32) (long) (old);                             \
  85                 break;                                                  \
  86         case 8:                                                         \
  87                 _o_ = (__u64) (long) (old);                             \
  88                 break;                                                  \
  89         default:                                                        \
  90                 break;                                                  \
  91         }                                                               \
  92         switch (size) {                                                 \
  93         case 1:                                                         \
  94                 _r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_);      \
  95                 break;                                                  \
  96                                                                         \
  97         case 2:                                                         \
  98                 _r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_);     \
  99                 break;                                                  \
 100                                                                         \
 101         case 4:                                                         \
 102                 _r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_);     \
 103                 break;                                                  \
 104                                                                         \
 105         case 8:                                                         \
 106                 _r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_);     \
 107                 break;                                                  \
 108                                                                         \
 109         default:                                                        \
 110                 _r_ = ia64_cmpxchg_called_with_bad_pointer();           \
 111                 break;                                                  \
 112         }                                                               \
 113         (__typeof__(old)) _r_;                                          \
 114 })
 115
 116 #define cmpxchg_acq(ptr, o, n)  \
 117         ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
 118 #define cmpxchg_rel(ptr, o, n)  \
 119         ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
 120
 121 /*
 122  * Worse still - early processor implementations actually just ignored
 123  * the acquire/release and did a full fence all the time.  Unfortunately
 124  * this meant a lot of badly written code that used .acq when they really
 125  * wanted .rel became legacy out in the wild - so when we made a cpu
 126  * that strictly did the .acq or .rel ... all that code started breaking - so
 127  * we had to back-pedal and keep the "legacy" behavior of a full fence :-(
 128  */
 129
 130 /* for compatibility with other platforms: */
 131 #define cmpxchg(ptr, o, n)      cmpxchg_acq((ptr), (o), (n))
 132 #define cmpxchg64(ptr, o, n)    cmpxchg_acq((ptr), (o), (n))
 133
 134 #define cmpxchg_local           cmpxchg
 135 #define cmpxchg64_local         cmpxchg64
 136
 137 #ifdef CONFIG_IA64_DEBUG_CMPXCHG
 138 # define CMPXCHG_BUGCHECK_DECL  int _cmpxchg_bugcheck_count = 128;
 139 # define CMPXCHG_BUGCHECK(v)                                            \
 140 do {                                                                    \
 141         if (_cmpxchg_bugcheck_count-- <= 0) {                           \
 142                 void *ip;                                               \
 143                 extern int printk(const char *fmt, ...);                \
 144                 ip = (void *) ia64_getreg(_IA64_REG_IP);                \
 145                 printk("CMPXCHG_BUGCHECK: stuck at %p on word %p\n", ip, (v));\
 146                 break;                                                  \
 147         }                                                               \
 148 } while (0)
 149 #else /* !CONFIG_IA64_DEBUG_CMPXCHG */
 150 # define CMPXCHG_BUGCHECK_DECL
 151 # define CMPXCHG_BUGCHECK(v)
 152 #endif /* !CONFIG_IA64_DEBUG_CMPXCHG */
 153
 154 #endif /* !__ASSEMBLY__ */
 155
 156 #endif /* _ASM_IA64_CMPXCHG_H */