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

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _ASM_IA64_CMPXCHG_H
   3 #define _ASM_IA64_CMPXCHG_H
   4
   5 /*
   6  * Compare/Exchange, forked from asm/intrinsics.h
   7  * which was:
   8  *
   9  *      Copyright (C) 2002-2003 Hewlett-Packard Co
  10  *      David Mosberger-Tang <davidm@hpl.hp.com>
  11  */
  12
  13 #ifndef __ASSEMBLY__
  14
  15 #include <linux/types.h>
  16 /* include compiler specific intrinsics */
  17 #include <asm/ia64regs.h>
  18 #ifdef __INTEL_COMPILER
  19 # include <asm/intel_intrin.h>
  20 #else
  21 # include <asm/gcc_intrin.h>
  22 #endif
  23
  24 /*
  25  * This function doesn't exist, so you'll get a linker error if
  26  * something tries to do an invalid xchg().
  27  */
  28 extern void ia64_xchg_called_with_bad_pointer(void);
  29
  30 #define __xchg(x, ptr, size)                                            \
  31 ({                                                                      \
  32         unsigned long __xchg_result;                                    \
  33                                                                         \
  34         switch (size) {                                                 \
  35         case 1:                                                         \
  36                 __xchg_result = ia64_xchg1((__u8 *)ptr, x);             \
  37                 break;                                                  \
  38                                                                         \
  39         case 2:                                                         \
  40                 __xchg_result = ia64_xchg2((__u16 *)ptr, x);            \
  41                 break;                                                  \
  42                                                                         \
  43         case 4:                                                         \
  44                 __xchg_result = ia64_xchg4((__u32 *)ptr, x);            \
  45                 break;                                                  \
  46                                                                         \
  47         case 8:                                                         \
  48                 __xchg_result = ia64_xchg8((__u64 *)ptr, x);            \
  49                 break;                                                  \
  50         default:                                                        \
  51                 ia64_xchg_called_with_bad_pointer();                    \
  52         }                                                               \
  53         __xchg_result;                                                  \
  54 })
  55
  56 #define xchg(ptr, x)                                                    \
  57 ((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
  58
  59 /*
  60  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  61  * store NEW in MEM.  Return the initial value in MEM.  Success is
  62  * indicated by comparing RETURN with OLD.
  63  */
  64
  65 /*
  66  * This function doesn't exist, so you'll get a linker error
  67  * if something tries to do an invalid cmpxchg().
  68  */
  69 extern long ia64_cmpxchg_called_with_bad_pointer(void);
  70
  71 #define ia64_cmpxchg(sem, ptr, old, new, size)                          \
  72 ({                                                                      \
  73         __u64 _o_, _r_;                                                 \
  74                                                                         \
  75         switch (size) {                                                 \
  76         case 1:                                                         \
  77                 _o_ = (__u8) (long) (old);                              \
  78                 break;                                                  \
  79         case 2:                                                         \
  80                 _o_ = (__u16) (long) (old);                             \
  81                 break;                                                  \
  82         case 4:                                                         \
  83                 _o_ = (__u32) (long) (old);                             \
  84                 break;                                                  \
  85         case 8:                                                         \
  86                 _o_ = (__u64) (long) (old);                             \
  87                 break;                                                  \
  88         default:                                                        \
  89                 break;                                                  \
  90         }                                                               \
  91         switch (size) {                                                 \
  92         case 1:                                                         \
  93                 _r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_);      \
  94                 break;                                                  \
  95                                                                         \
  96         case 2:                                                         \
  97                 _r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_);     \
  98                 break;                                                  \
  99                                                                         \
 100         case 4:                                                         \
 101                 _r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_);     \
 102                 break;                                                  \
 103                                                                         \
 104         case 8:                                                         \
 105                 _r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_);     \
 106                 break;                                                  \
 107                                                                         \
 108         default:                                                        \
 109                 _r_ = ia64_cmpxchg_called_with_bad_pointer();           \
 110                 break;                                                  \
 111         }                                                               \
 112         (__typeof__(old)) _r_;                                          \
 113 })
 114
 115 #define cmpxchg_acq(ptr, o, n)  \
 116         ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
 117 #define cmpxchg_rel(ptr, o, n)  \
 118         ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
 119
 120 /*
 121  * Worse still - early processor implementations actually just ignored
 122  * the acquire/release and did a full fence all the time.  Unfortunately
 123  * this meant a lot of badly written code that used .acq when they really
 124  * wanted .rel became legacy out in the wild - so when we made a cpu
 125  * that strictly did the .acq or .rel ... all that code started breaking - so
 126  * we had to back-pedal and keep the "legacy" behavior of a full fence :-(
 127  */
 128
 129 /* for compatibility with other platforms: */
 130 #define cmpxchg(ptr, o, n)      cmpxchg_acq((ptr), (o), (n))
 131 #define cmpxchg64(ptr, o, n)    cmpxchg_acq((ptr), (o), (n))
 132
 133 #define cmpxchg_local           cmpxchg
 134 #define cmpxchg64_local         cmpxchg64
 135
 136 #ifdef CONFIG_IA64_DEBUG_CMPXCHG
 137 # define CMPXCHG_BUGCHECK_DECL  int _cmpxchg_bugcheck_count = 128;
 138 # define CMPXCHG_BUGCHECK(v)                                            \
 139 do {                                                                    \
 140         if (_cmpxchg_bugcheck_count-- <= 0) {                           \
 141                 void *ip;                                               \
 142                 extern int printk(const char *fmt, ...);                \
 143                 ip = (void *) ia64_getreg(_IA64_REG_IP);                \
 144                 printk("CMPXCHG_BUGCHECK: stuck at %p on word %p\n", ip, (v));\
 145                 break;                                                  \
 146         }                                                               \
 147 } while (0)
 148 #else /* !CONFIG_IA64_DEBUG_CMPXCHG */
 149 # define CMPXCHG_BUGCHECK_DECL
 150 # define CMPXCHG_BUGCHECK(v)
 151 #endif /* !CONFIG_IA64_DEBUG_CMPXCHG */
 152
 153 #endif /* !__ASSEMBLY__ */
 154
 155 #endif /* _ASM_IA64_CMPXCHG_H */