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

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _UAPI_ASM_IA64_CMPXCHG_H
   3 #define _UAPI_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 #include <asm/gcc_intrin.h>
  19
  20 /*
  21  * This function doesn't exist, so you'll get a linker error if
  22  * something tries to do an invalid xchg().
  23  */
  24 extern void ia64_xchg_called_with_bad_pointer(void);
  25
  26 #define __xchg(x, ptr, size)                                            \
  27 ({                                                                      \
  28         unsigned long __xchg_result;                                    \
  29                                                                         \
  30         switch (size) {                                                 \
  31         case 1:                                                         \
  32                 __xchg_result = ia64_xchg1((__u8 __force *)ptr, x);     \
  33                 break;                                                  \
  34                                                                         \
  35         case 2:                                                         \
  36                 __xchg_result = ia64_xchg2((__u16 __force *)ptr, x);    \
  37                 break;                                                  \
  38                                                                         \
  39         case 4:                                                         \
  40                 __xchg_result = ia64_xchg4((__u32 __force *)ptr, x);    \
  41                 break;                                                  \
  42                                                                         \
  43         case 8:                                                         \
  44                 __xchg_result = ia64_xchg8((__u64 __force *)ptr, x);    \
  45                 break;                                                  \
  46         default:                                                        \
  47                 ia64_xchg_called_with_bad_pointer();                    \
  48         }                                                               \
  49         (__typeof__ (*(ptr)) __force) __xchg_result;                    \
  50 })
  51
  52 #ifndef __KERNEL__
  53 #define xchg(ptr, x)                                                    \
  54 ({(__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr)));})
  55 #endif
  56
  57 /*
  58  * Atomic compare and exchange.  Compare OLD with MEM, if identical,
  59  * store NEW in MEM.  Return the initial value in MEM.  Success is
  60  * indicated by comparing RETURN with OLD.
  61  */
  62
  63 /*
  64  * This function doesn't exist, so you'll get a linker error
  65  * if something tries to do an invalid cmpxchg().
  66  */
  67 extern long ia64_cmpxchg_called_with_bad_pointer(void);
  68
  69 #define ia64_cmpxchg(sem, ptr, old, new, size)                          \
  70 ({                                                                      \
  71         __u64 _o_, _r_;                                                 \
  72                                                                         \
  73         switch (size) {                                                 \
  74         case 1:                                                         \
  75                 _o_ = (__u8) (long __force) (old);                      \
  76                 break;                                                  \
  77         case 2:                                                         \
  78                 _o_ = (__u16) (long __force) (old);                     \
  79                 break;                                                  \
  80         case 4:                                                         \
  81                 _o_ = (__u32) (long __force) (old);                     \
  82                 break;                                                  \
  83         case 8:                                                         \
  84                 _o_ = (__u64) (long __force) (old);                     \
  85                 break;                                                  \
  86         default:                                                        \
  87                 break;                                                  \
  88         }                                                               \
  89         switch (size) {                                                 \
  90         case 1:                                                         \
  91                 _r_ = ia64_cmpxchg1_##sem((__u8 __force *) ptr, new, _o_);      \
  92                 break;                                                  \
  93                                                                         \
  94         case 2:                                                         \
  95                 _r_ = ia64_cmpxchg2_##sem((__u16 __force *) ptr, new, _o_);     \
  96                 break;                                                  \
  97                                                                         \
  98         case 4:                                                         \
  99                 _r_ = ia64_cmpxchg4_##sem((__u32 __force *) ptr, new, _o_);     \
 100                 break;                                                  \
 101                                                                         \
 102         case 8:                                                         \
 103                 _r_ = ia64_cmpxchg8_##sem((__u64 __force *) ptr, new, _o_);     \
 104                 break;                                                  \
 105                                                                         \
 106         default:                                                        \
 107                 _r_ = ia64_cmpxchg_called_with_bad_pointer();           \
 108                 break;                                                  \
 109         }                                                               \
 110         (__typeof__(old) __force) _r_;                                  \
 111 })
 112
 113 #define cmpxchg_acq(ptr, o, n)  \
 114         ia64_cmpxchg(acq, (ptr), (o), (n), sizeof(*(ptr)))
 115 #define cmpxchg_rel(ptr, o, n)  \
 116         ia64_cmpxchg(rel, (ptr), (o), (n), sizeof(*(ptr)))
 117
 118 /*
 119  * Worse still - early processor implementations actually just ignored
 120  * the acquire/release and did a full fence all the time.  Unfortunately
 121  * this meant a lot of badly written code that used .acq when they really
 122  * wanted .rel became legacy out in the wild - so when we made a cpu
 123  * that strictly did the .acq or .rel ... all that code started breaking - so
 124  * we had to back-pedal and keep the "legacy" behavior of a full fence :-(
 125  */
 126
 127 #ifndef __KERNEL__
 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 #endif
 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 /* _UAPI_ASM_IA64_CMPXCHG_H */