include/asm-generic/futex.h

   1 #ifndef _ASM_GENERIC_FUTEX_H
   2 #define _ASM_GENERIC_FUTEX_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/futex.h>
   7 #include <asm/errno.h>
   8 #include <asm/uaccess.h>
   9
  10 static inline int
  11 futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  12 {
  13         int op = (encoded_op >> 28) & 7;
  14         int cmp = (encoded_op >> 24) & 15;
  15         int oparg = (encoded_op << 8) >> 20;
  16         int cmparg = (encoded_op << 20) >> 20;
  17         int oldval = 0, ret;
  18         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  19                 oparg = 1 << oparg;
  20
  21         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  22                 return -EFAULT;
  23
  24         inc_preempt_count();
  25
  26         switch (op) {
  27         case FUTEX_OP_SET:
  28         case FUTEX_OP_ADD:
  29         case FUTEX_OP_OR:
  30         case FUTEX_OP_ANDN:
  31         case FUTEX_OP_XOR:
  32         default:
  33                 ret = -ENOSYS;
  34         }
  35
  36         dec_preempt_count();
  37
  38         if (!ret) {
  39                 switch (cmp) {
  40                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  41                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  42                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  43                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  44                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  45                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  46                 default: ret = -ENOSYS;
  47                 }
  48         }
  49         return ret;
  50 }
  51
  52 #endif
  53 #endif