linux/arch/frv/include/asm/cmpxchg.h
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   1/* xchg and cmpxchg operation emulation for FR-V
   2 *
   3 * For an explanation of how atomic ops work in this arch, see:
   4 *   Documentation/frv/atomic-ops.txt
   5 *
   6 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   7 * Written by David Howells (dhowells@redhat.com)
   8 *
   9 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License
  11 * as published by the Free Software Foundation; either version
  12 * 2 of the License, or (at your option) any later version.
  13 */
  14#ifndef _ASM_CMPXCHG_H
  15#define _ASM_CMPXCHG_H
  16
  17#include <linux/types.h>
  18
  19/*****************************************************************************/
  20/*
  21 * exchange value with memory
  22 */
  23extern uint64_t __xchg_64(uint64_t i, volatile void *v);
  24
  25#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
  26
  27#define xchg(ptr, x)                                                            \
  28({                                                                              \
  29        __typeof__(ptr) __xg_ptr = (ptr);                                       \
  30        __typeof__(*(ptr)) __xg_orig;                                           \
  31                                                                                \
  32        switch (sizeof(__xg_orig)) {                                            \
  33        case 4:                                                                 \
  34                asm volatile(                                                   \
  35                        "swap%I0 %M0,%1"                                        \
  36                        : "+m"(*__xg_ptr), "=r"(__xg_orig)                      \
  37                        : "1"(x)                                                \
  38                        : "memory"                                              \
  39                        );                                                      \
  40                break;                                                          \
  41                                                                                \
  42        default:                                                                \
  43                __xg_orig = (__typeof__(__xg_orig))0;                           \
  44                asm volatile("break");                                          \
  45                break;                                                          \
  46        }                                                                       \
  47                                                                                \
  48        __xg_orig;                                                              \
  49})
  50
  51#else
  52
  53extern uint32_t __xchg_32(uint32_t i, volatile void *v);
  54
  55#define xchg(ptr, x)                                                                            \
  56({                                                                                              \
  57        __typeof__(ptr) __xg_ptr = (ptr);                                                       \
  58        __typeof__(*(ptr)) __xg_orig;                                                           \
  59                                                                                                \
  60        switch (sizeof(__xg_orig)) {                                                            \
  61        case 4: __xg_orig = (__typeof__(*(ptr))) __xchg_32((uint32_t) x, __xg_ptr);     break;  \
  62        default:                                                                                \
  63                __xg_orig = (__typeof__(__xg_orig))0;                                                                   \
  64                asm volatile("break");                                                          \
  65                break;                                                                          \
  66        }                                                                                       \
  67        __xg_orig;                                                                              \
  68})
  69
  70#endif
  71
  72#define tas(ptr) (xchg((ptr), 1))
  73
  74/*****************************************************************************/
  75/*
  76 * compare and conditionally exchange value with memory
  77 * - if (*ptr == test) then orig = *ptr; *ptr = test;
  78 * - if (*ptr != test) then orig = *ptr;
  79 */
  80extern uint64_t __cmpxchg_64(uint64_t test, uint64_t new, volatile uint64_t *v);
  81
  82#ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS
  83
  84#define cmpxchg(ptr, test, new)                                                 \
  85({                                                                              \
  86        __typeof__(ptr) __xg_ptr = (ptr);                                       \
  87        __typeof__(*(ptr)) __xg_orig, __xg_tmp;                                 \
  88        __typeof__(*(ptr)) __xg_test = (test);                                  \
  89        __typeof__(*(ptr)) __xg_new = (new);                                    \
  90                                                                                \
  91        switch (sizeof(__xg_orig)) {                                            \
  92        case 4:                                                                 \
  93                asm volatile(                                                   \
  94                        "0:                                             \n"     \
  95                        "       orcc            gr0,gr0,gr0,icc3        \n"     \
  96                        "       ckeq            icc3,cc7                \n"     \
  97                        "       ld.p            %M0,%1                  \n"     \
  98                        "       orcr            cc7,cc7,cc3             \n"     \
  99                        "       sub%I4cc        %1,%4,%2,icc0           \n"     \
 100                        "       bne             icc0,#0,1f              \n"     \
 101                        "       cst.p           %3,%M0          ,cc3,#1 \n"     \
 102                        "       corcc           gr29,gr29,gr0   ,cc3,#1 \n"     \
 103                        "       beq             icc3,#0,0b              \n"     \
 104                        "1:                                             \n"     \
 105                        : "+U"(*__xg_ptr), "=&r"(__xg_orig), "=&r"(__xg_tmp)    \
 106                        : "r"(__xg_new), "NPr"(__xg_test)                       \
 107                        : "memory", "cc7", "cc3", "icc3", "icc0"                \
 108                        );                                                      \
 109                break;                                                          \
 110                                                                                \
 111        default:                                                                \
 112                __xg_orig = (__typeof__(__xg_orig))0;                           \
 113                asm volatile("break");                                          \
 114                break;                                                          \
 115        }                                                                       \
 116                                                                                \
 117        __xg_orig;                                                              \
 118})
 119
 120#else
 121
 122extern uint32_t __cmpxchg_32(uint32_t *v, uint32_t test, uint32_t new);
 123
 124#define cmpxchg(ptr, test, new)                                                 \
 125({                                                                              \
 126        __typeof__(ptr) __xg_ptr = (ptr);                                       \
 127        __typeof__(*(ptr)) __xg_orig;                                           \
 128        __typeof__(*(ptr)) __xg_test = (test);                                  \
 129        __typeof__(*(ptr)) __xg_new = (new);                                    \
 130                                                                                \
 131        switch (sizeof(__xg_orig)) {                                            \
 132        case 4: __xg_orig = (__force __typeof__(*ptr))                          \
 133                        __cmpxchg_32((__force uint32_t *)__xg_ptr,              \
 134                                         (__force uint32_t)__xg_test,           \
 135                                         (__force uint32_t)__xg_new); break;    \
 136        default:                                                                \
 137                __xg_orig = (__typeof__(__xg_orig))0;                           \
 138                asm volatile("break");                                          \
 139                break;                                                          \
 140        }                                                                       \
 141                                                                                \
 142        __xg_orig;                                                              \
 143})
 144
 145#endif
 146
 147#include <asm-generic/cmpxchg-local.h>
 148
 149static inline unsigned long __cmpxchg_local(volatile void *ptr,
 150                                      unsigned long old,
 151                                      unsigned long new, int size)
 152{
 153        switch (size) {
 154        case 4:
 155                return cmpxchg((unsigned long *)ptr, old, new);
 156        default:
 157                return __cmpxchg_local_generic(ptr, old, new, size);
 158        }
 159
 160        return old;
 161}
 162
 163/*
 164 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 165 * them available.
 166 */
 167#define cmpxchg_local(ptr, o, n)                                        \
 168        ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 169                        (unsigned long)(n), sizeof(*(ptr))))
 170#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 171
 172#endif /* _ASM_CMPXCHG_H */
 173