include/asm-x86_64/futex.h

   1 #ifndef _ASM_FUTEX_H
   2 #define _ASM_FUTEX_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/futex.h>
   7 #include <asm/errno.h>
   8 #include <asm/system.h>
   9 #include <asm/uaccess.h>
  10
  11 #define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
  12   __asm__ __volatile (                                          \
  13 "1:     " insn "\n"                                             \
  14 "2:     .section .fixup,\"ax\"\n\
  15 3:      mov     %3, %1\n\
  16         jmp     2b\n\
  17         .previous\n\
  18         .section __ex_table,\"a\"\n\
  19         .align  8\n\
  20         .quad   1b,3b\n\
  21         .previous"                                              \
  22         : "=r" (oldval), "=r" (ret), "=m" (*uaddr)              \
  23         : "i" (-EFAULT), "m" (*uaddr), "0" (oparg), "1" (0))
  24
  25 #define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
  26   __asm__ __volatile (                                          \
  27 "1:     movl    %2, %0\n\
  28         movl    %0, %3\n"                                       \
  29         insn "\n"                                               \
  30 "2:     " LOCK_PREFIX "cmpxchgl %3, %2\n\
  31         jnz     1b\n\
  32 3:      .section .fixup,\"ax\"\n\
  33 4:      mov     %5, %1\n\
  34         jmp     3b\n\
  35         .previous\n\
  36         .section __ex_table,\"a\"\n\
  37         .align  8\n\
  38         .quad   1b,4b,2b,4b\n\
  39         .previous"                                              \
  40         : "=&a" (oldval), "=&r" (ret), "=m" (*uaddr),           \
  41           "=&r" (tem)                                           \
  42         : "r" (oparg), "i" (-EFAULT), "m" (*uaddr), "1" (0))
  43
  44 static inline int
  45 futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  46 {
  47         int op = (encoded_op >> 28) & 7;
  48         int cmp = (encoded_op >> 24) & 15;
  49         int oparg = (encoded_op << 8) >> 20;
  50         int cmparg = (encoded_op << 20) >> 20;
  51         int oldval = 0, ret, tem;
  52         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  53                 oparg = 1 << oparg;
  54
  55         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  56                 return -EFAULT;
  57
  58         inc_preempt_count();
  59
  60         switch (op) {
  61         case FUTEX_OP_SET:
  62                 __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
  63                 break;
  64         case FUTEX_OP_ADD:
  65                 __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
  66                                    uaddr, oparg);
  67                 break;
  68         case FUTEX_OP_OR:
  69                 __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
  70                 break;
  71         case FUTEX_OP_ANDN:
  72                 __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
  73                 break;
  74         case FUTEX_OP_XOR:
  75                 __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
  76                 break;
  77         default:
  78                 ret = -ENOSYS;
  79         }
  80
  81         dec_preempt_count();
  82
  83         if (!ret) {
  84                 switch (cmp) {
  85                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  86                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  87                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  88                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  89                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  90                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  91                 default: ret = -ENOSYS;
  92                 }
  93         }
  94         return ret;
  95 }
  96
  97 #endif
  98 #endif