include/asm-ppc64/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/memory.h>
   9 #include <asm/uaccess.h>
  10
  11 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
  12   __asm__ __volatile (SYNC_ON_SMP                               \
  13 "1:     lwarx   %0,0,%2\n"                                      \
  14         insn                                                    \
  15 "2:     stwcx.  %1,0,%2\n\
  16         bne-    1b\n\
  17         li      %1,0\n\
  18 3:      .section .fixup,\"ax\"\n\
  19 4:      li      %1,%3\n\
  20         b       3b\n\
  21         .previous\n\
  22         .section __ex_table,\"a\"\n\
  23         .align 3\n\
  24         .llong  1b,4b,2b,4b\n\
  25         .previous"                                              \
  26         : "=&r" (oldval), "=&r" (ret)                           \
  27         : "b" (uaddr), "i" (-EFAULT), "1" (oparg)               \
  28         : "cr0", "memory")
  29
  30 static inline int
  31 futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  32 {
  33         int op = (encoded_op >> 28) & 7;
  34         int cmp = (encoded_op >> 24) & 15;
  35         int oparg = (encoded_op << 8) >> 20;
  36         int cmparg = (encoded_op << 20) >> 20;
  37         int oldval = 0, ret;
  38         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  39                 oparg = 1 << oparg;
  40
  41         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  42                 return -EFAULT;
  43
  44         inc_preempt_count();
  45
  46         switch (op) {
  47         case FUTEX_OP_SET:
  48                 __futex_atomic_op("", ret, oldval, uaddr, oparg);
  49                 break;
  50         case FUTEX_OP_ADD:
  51                 __futex_atomic_op("add %1,%0,%1\n", ret, oldval, uaddr, oparg);
  52                 break;
  53         case FUTEX_OP_OR:
  54                 __futex_atomic_op("or %1,%0,%1\n", ret, oldval, uaddr, oparg);
  55                 break;
  56         case FUTEX_OP_ANDN:
  57                 __futex_atomic_op("andc %1,%0,%1\n", ret, oldval, uaddr, oparg);
  58                 break;
  59         case FUTEX_OP_XOR:
  60                 __futex_atomic_op("xor %1,%0,%1\n", ret, oldval, uaddr, oparg);
  61                 break;
  62         default:
  63                 ret = -ENOSYS;
  64         }
  65
  66         dec_preempt_count();
  67
  68         if (!ret) {
  69                 switch (cmp) {
  70                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  71                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  72                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  73                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  74                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  75                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  76                 default: ret = -ENOSYS;
  77                 }
  78         }
  79         return ret;
  80 }
  81
  82 #endif
  83 #endif