include/asm-i386/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/processor.h>
  10 #include <asm/uaccess.h>
  11
  12 #define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
  13   __asm__ __volatile (                                          \
  14 "1:     " insn "\n"                                             \
  15 "2:     .section .fixup,\"ax\"\n\
  16 3:      mov     %3, %1\n\
  17         jmp     2b\n\
  18         .previous\n\
  19         .section __ex_table,\"a\"\n\
  20         .align  8\n\
  21         .long   1b,3b\n\
  22         .previous"                                              \
  23         : "=r" (oldval), "=r" (ret), "+m" (*uaddr)              \
  24         : "i" (-EFAULT), "0" (oparg), "1" (0))
  25
  26 #define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
  27   __asm__ __volatile (                                          \
  28 "1:     movl    %2, %0\n\
  29         movl    %0, %3\n"                                       \
  30         insn "\n"                                               \
  31 "2:     " LOCK_PREFIX "cmpxchgl %3, %2\n\
  32         jnz     1b\n\
  33 3:      .section .fixup,\"ax\"\n\
  34 4:      mov     %5, %1\n\
  35         jmp     3b\n\
  36         .previous\n\
  37         .section __ex_table,\"a\"\n\
  38         .align  8\n\
  39         .long   1b,4b,2b,4b\n\
  40         .previous"                                              \
  41         : "=&a" (oldval), "=&r" (ret), "+m" (*uaddr),           \
  42           "=&r" (tem)                                           \
  43         : "r" (oparg), "i" (-EFAULT), "1" (0))
  44
  45 static inline int
  46 futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  47 {
  48         int op = (encoded_op >> 28) & 7;
  49         int cmp = (encoded_op >> 24) & 15;
  50         int oparg = (encoded_op << 8) >> 20;
  51         int cmparg = (encoded_op << 20) >> 20;
  52         int oldval = 0, ret, tem;
  53         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  54                 oparg = 1 << oparg;
  55
  56         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  57                 return -EFAULT;
  58
  59         inc_preempt_count();
  60
  61         if (op == FUTEX_OP_SET)
  62                 __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
  63         else {
  64 #ifndef CONFIG_X86_BSWAP
  65                 if (boot_cpu_data.x86 == 3)
  66                         ret = -ENOSYS;
  67                 else
  68 #endif
  69                 switch (op) {
  70                 case FUTEX_OP_ADD:
  71                         __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret,
  72                                            oldval, uaddr, oparg);
  73                         break;
  74                 case FUTEX_OP_OR:
  75                         __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr,
  76                                            oparg);
  77                         break;
  78                 case FUTEX_OP_ANDN:
  79                         __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr,
  80                                            ~oparg);
  81                         break;
  82                 case FUTEX_OP_XOR:
  83                         __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr,
  84                                            oparg);
  85                         break;
  86                 default:
  87                         ret = -ENOSYS;
  88                 }
  89         }
  90
  91         dec_preempt_count();
  92
  93         if (!ret) {
  94                 switch (cmp) {
  95                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  96                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  97                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  98                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  99                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
 100                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
 101                 default: ret = -ENOSYS;
 102                 }
 103         }
 104         return ret;
 105 }
 106
 107 static inline int
 108 futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 109 {
 110         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 111                 return -EFAULT;
 112
 113         __asm__ __volatile__(
 114                 "1:     " LOCK_PREFIX "cmpxchgl %3, %1          \n"
 115
 116                 "2:     .section .fixup, \"ax\"                 \n"
 117                 "3:     mov     %2, %0                          \n"
 118                 "       jmp     2b                              \n"
 119                 "       .previous                               \n"
 120
 121                 "       .section __ex_table, \"a\"              \n"
 122                 "       .align  8                               \n"
 123                 "       .long   1b,3b                           \n"
 124                 "       .previous                               \n"
 125
 126                 : "=a" (oldval), "+m" (*uaddr)
 127                 : "i" (-EFAULT), "r" (newval), "0" (oldval)
 128                 : "memory"
 129         );
 130
 131         return oldval;
 132 }
 133
 134 #endif
 135 #endif