git.oblomov.eu Git - linux-2.6/blob - include/asm-x86/futex_64.h

   1 #ifndef _ASM_FUTEX_H
   2 #define _ASM_FUTEX_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/futex.h>
   7
   8 #include <asm/asm.h>
   9 #include <asm/errno.h>
  10 #include <asm/system.h>
  11 #include <asm/uaccess.h>
  12
  13 #define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
  14   __asm__ __volatile (                                          \
  15 "1:     " insn "\n"                                             \
  16 "2:     .section .fixup,\"ax\"\n\
  17 3:      mov     %3, %1\n\
  18         jmp     2b\n\
  19         .previous\n\
  20         .section __ex_table,\"a\"\n\
  21         .align  8\n"                                            \
  22         _ASM_PTR "1b,3b\n                                       \
  23         .previous"                                              \
  24         : "=r" (oldval), "=r" (ret), "+m" (*uaddr)              \
  25         : "i" (-EFAULT), "0" (oparg), "1" (0))
  26
  27 #define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg)     \
  28   __asm__ __volatile (                                          \
  29 "1:     movl    %2, %0\n\
  30         movl    %0, %3\n"                                       \
  31         insn "\n"                                               \
  32 "2:     " LOCK_PREFIX "cmpxchgl %3, %2\n\
  33         jnz     1b\n\
  34 3:      .section .fixup,\"ax\"\n\
  35 4:      mov     %5, %1\n\
  36         jmp     3b\n\
  37         .previous\n\
  38         .section __ex_table,\"a\"\n\
  39         .align  8\n"                                            \
  40         _ASM_PTR "1b,4b,2b,4b\n                                 \
  41         .previous"                                              \
  42         : "=&a" (oldval), "=&r" (ret), "+m" (*uaddr),           \
  43           "=&r" (tem)                                           \
  44         : "r" (oparg), "i" (-EFAULT), "1" (0))
  45
  46 static inline int
  47 futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  48 {
  49         int op = (encoded_op >> 28) & 7;
  50         int cmp = (encoded_op >> 24) & 15;
  51         int oparg = (encoded_op << 8) >> 20;
  52         int cmparg = (encoded_op << 20) >> 20;
  53         int oldval = 0, ret, tem;
  54         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  55                 oparg = 1 << oparg;
  56
  57         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  58                 return -EFAULT;
  59
  60         pagefault_disable();
  61
  62         switch (op) {
  63         case FUTEX_OP_SET:
  64                 __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
  65                 break;
  66         case FUTEX_OP_ADD:
  67                 __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
  68                                    uaddr, oparg);
  69                 break;
  70         case FUTEX_OP_OR:
  71                 __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
  72                 break;
  73         case FUTEX_OP_ANDN:
  74                 __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
  75                 break;
  76         case FUTEX_OP_XOR:
  77                 __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
  78                 break;
  79         default:
  80                 ret = -ENOSYS;
  81         }
  82
  83         pagefault_enable();
  84
  85         if (!ret) {
  86                 switch (cmp) {
  87                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  88                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  89                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  90                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  91                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  92                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  93                 default: ret = -ENOSYS;
  94                 }
  95         }
  96         return ret;
  97 }
  98
  99 static inline int
 100 futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 101 {
 102         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 103                 return -EFAULT;
 104
 105         __asm__ __volatile__(
 106                 "1:     " LOCK_PREFIX "cmpxchgl %3, %1          \n"
 107
 108                 "2:     .section .fixup, \"ax\"                 \n"
 109                 "3:     mov     %2, %0                          \n"
 110                 "       jmp     2b                              \n"
 111                 "       .previous                               \n"
 112
 113                 "       .section __ex_table, \"a\"              \n"
 114                 "       .align  8                               \n"
 115                         _ASM_PTR " 1b,3b                        \n"
 116                 "       .previous                               \n"
 117
 118                 : "=a" (oldval), "+m" (*uaddr)
 119                 : "i" (-EFAULT), "r" (newval), "0" (oldval)
 120                 : "memory"
 121         );
 122
 123         return oldval;
 124 }
 125
 126 #endif
 127 #endif