linux/arch/alpha/include/asm/futex.h
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   1#ifndef _ASM_ALPHA_FUTEX_H
   2#define _ASM_ALPHA_FUTEX_H
   3
   4#ifdef __KERNEL__
   5
   6#include <linux/futex.h>
   7#include <linux/uaccess.h>
   8#include <asm/errno.h>
   9#include <asm/barrier.h>
  10
  11#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)      \
  12        __asm__ __volatile__(                                   \
  13                __ASM_SMP_MB                                    \
  14        "1:     ldl_l   %0,0(%2)\n"                             \
  15                insn                                            \
  16        "2:     stl_c   %1,0(%2)\n"                             \
  17        "       beq     %1,4f\n"                                \
  18        "       mov     $31,%1\n"                               \
  19        "3:     .subsection 2\n"                                \
  20        "4:     br      1b\n"                                   \
  21        "       .previous\n"                                    \
  22        "       .section __ex_table,\"a\"\n"                    \
  23        "       .long   1b-.\n"                                 \
  24        "       lda     $31,3b-1b(%1)\n"                        \
  25        "       .long   2b-.\n"                                 \
  26        "       lda     $31,3b-2b(%1)\n"                        \
  27        "       .previous\n"                                    \
  28        :       "=&r" (oldval), "=&r"(ret)                      \
  29        :       "r" (uaddr), "r"(oparg)                         \
  30        :       "memory")
  31
  32static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
  33{
  34        int op = (encoded_op >> 28) & 7;
  35        int cmp = (encoded_op >> 24) & 15;
  36        int oparg = (encoded_op << 8) >> 20;
  37        int cmparg = (encoded_op << 20) >> 20;
  38        int oldval = 0, ret;
  39        if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  40                oparg = 1 << oparg;
  41
  42        if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  43                return -EFAULT;
  44
  45        pagefault_disable();
  46
  47        switch (op) {
  48        case FUTEX_OP_SET:
  49                __futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
  50                break;
  51        case FUTEX_OP_ADD:
  52                __futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
  53                break;
  54        case FUTEX_OP_OR:
  55                __futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
  56                break;
  57        case FUTEX_OP_ANDN:
  58                __futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
  59                break;
  60        case FUTEX_OP_XOR:
  61                __futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
  62                break;
  63        default:
  64                ret = -ENOSYS;
  65        }
  66
  67        pagefault_enable();
  68
  69        if (!ret) {
  70                switch (cmp) {
  71                case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  72                case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  73                case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  74                case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  75                case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  76                case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  77                default: ret = -ENOSYS;
  78                }
  79        }
  80        return ret;
  81}
  82
  83static inline int
  84futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
  85                              u32 oldval, u32 newval)
  86{
  87        int ret = 0, cmp;
  88        u32 prev;
  89
  90        if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  91                return -EFAULT;
  92
  93        __asm__ __volatile__ (
  94                __ASM_SMP_MB
  95        "1:     ldl_l   %1,0(%3)\n"
  96        "       cmpeq   %1,%4,%2\n"
  97        "       beq     %2,3f\n"
  98        "       mov     %5,%2\n"
  99        "2:     stl_c   %2,0(%3)\n"
 100        "       beq     %2,4f\n"
 101        "3:     .subsection 2\n"
 102        "4:     br      1b\n"
 103        "       .previous\n"
 104        "       .section __ex_table,\"a\"\n"
 105        "       .long   1b-.\n"
 106        "       lda     $31,3b-1b(%0)\n"
 107        "       .long   2b-.\n"
 108        "       lda     $31,3b-2b(%0)\n"
 109        "       .previous\n"
 110        :       "+r"(ret), "=&r"(prev), "=&r"(cmp)
 111        :       "r"(uaddr), "r"((long)(int)oldval), "r"(newval)
 112        :       "memory");
 113
 114        *uval = prev;
 115        return ret;
 116}
 117
 118#endif /* __KERNEL__ */
 119#endif /* _ASM_ALPHA_FUTEX_H */
 120
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