LXR linux/arch/powerpc/include/asm/futex.h

   1#ifndef _ASM_POWERPC_FUTEX_H
   2#define _ASM_POWERPC_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/synch.h>
  10#include <asm/asm-compat.h>
  11
  12#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
  13  __asm__ __volatile ( \
  14        PPC_RELEASE_BARRIER \
  15"1:     lwarx   %0,0,%2\n" \
  16        insn \
  17        PPC405_ERR77(0, %2) \
  18"2:     stwcx.  %1,0,%2\n" \
  19        "bne-   1b\n" \
  20        "li     %1,0\n" \
  21"3:     .section .fixup,\"ax\"\n" \
  22"4:     li      %1,%3\n" \
  23        "b      3b\n" \
  24        ".previous\n" \
  25        ".section __ex_table,\"a\"\n" \
  26        ".align 3\n" \
  27        PPC_LONG "1b,4b,2b,4b\n" \
  28        ".previous" \
  29        : "=&r" (oldval), "=&r" (ret) \
  30        : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
  31        : "cr0", "memory")
  32
  33static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
  34{
  35        int op = (encoded_op >> 28) & 7;
  36        int cmp = (encoded_op >> 24) & 15;
  37        int oparg = (encoded_op << 8) >> 20;
  38        int cmparg = (encoded_op << 20) >> 20;
  39        int oldval = 0, ret;
  40        if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  41                oparg = 1 << oparg;
  42
  43        if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
  44                return -EFAULT;
  45
  46        pagefault_disable();
  47
  48        switch (op) {
  49        case FUTEX_OP_SET:
  50                __futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
  51                break;
  52        case FUTEX_OP_ADD:
  53                __futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
  54                break;
  55        case FUTEX_OP_OR:
  56                __futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
  57                break;
  58        case FUTEX_OP_ANDN:
  59                __futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
  60                break;
  61        case FUTEX_OP_XOR:
  62                __futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
  63                break;
  64        default:
  65                ret = -ENOSYS;
  66        }
  67
  68        pagefault_enable();
  69
  70        if (!ret) {
  71                switch (cmp) {
  72                case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  73                case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  74                case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  75                case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  76                case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  77                case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  78                default: ret = -ENOSYS;
  79                }
  80        }
  81        return ret;
  82}
  83
  84static inline int
  85futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
  86                              u32 oldval, u32 newval)
  87{
  88        int ret = 0;
  89        u32 prev;
  90
  91        if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  92                return -EFAULT;
  93
  94        __asm__ __volatile__ (
  95        PPC_RELEASE_BARRIER
  96"1:     lwarx   %1,0,%3         # futex_atomic_cmpxchg_inatomic\n\
  97        cmpw    0,%1,%4\n\
  98        bne-    3f\n"
  99        PPC405_ERR77(0,%3)
 100"2:     stwcx.  %5,0,%3\n\
 101        bne-    1b\n"
 102        PPC_ACQUIRE_BARRIER
 103"3:     .section .fixup,\"ax\"\n\
 1044:      li      %0,%6\n\
 105        b       3b\n\
 106        .previous\n\
 107        .section __ex_table,\"a\"\n\
 108        .align 3\n\
 109        " PPC_LONG "1b,4b,2b,4b\n\
 110        .previous" \
 111        : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
 112        : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
 113        : "cc", "memory");
 114
 115        *uval = prev;
 116        return ret;
 117}
 118
 119#endif /* __KERNEL__ */
 120#endif /* _ASM_POWERPC_FUTEX_H */
 121