arch/tile/include/asm/futex.h

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * These routines make two important assumptions:
  15  *
  16  * 1. atomic_t is really an int and can be freely cast back and forth
  17  *    (validated in __init_atomic_per_cpu).
  18  *
  19  * 2. userspace uses sys_cmpxchg() for all atomic operations, thus using
  20  *    the same locking convention that all the kernel atomic routines use.
  21  */
  22
  23 #ifndef _ASM_TILE_FUTEX_H
  24 #define _ASM_TILE_FUTEX_H
  25
  26 #ifndef __ASSEMBLY__
  27
  28 #include <linux/futex.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/errno.h>
  31
  32 extern struct __get_user futex_set(int *v, int i);
  33 extern struct __get_user futex_add(int *v, int n);
  34 extern struct __get_user futex_or(int *v, int n);
  35 extern struct __get_user futex_andn(int *v, int n);
  36 extern struct __get_user futex_cmpxchg(int *v, int o, int n);
  37
  38 #ifndef __tilegx__
  39 extern struct __get_user futex_xor(int *v, int n);
  40 #else
  41 static inline struct __get_user futex_xor(int __user *uaddr, int n)
  42 {
  43         struct __get_user asm_ret = __get_user_4(uaddr);
  44         if (!asm_ret.err) {
  45                 int oldval, newval;
  46                 do {
  47                         oldval = asm_ret.val;
  48                         newval = oldval ^ n;
  49                         asm_ret = futex_cmpxchg(uaddr, oldval, newval);
  50                 } while (asm_ret.err == 0 && oldval != asm_ret.val);
  51         }
  52         return asm_ret;
  53 }
  54 #endif
  55
  56 static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
  57 {
  58         int op = (encoded_op >> 28) & 7;
  59         int cmp = (encoded_op >> 24) & 15;
  60         int oparg = (encoded_op << 8) >> 20;
  61         int cmparg = (encoded_op << 20) >> 20;
  62         int ret;
  63         struct __get_user asm_ret;
  64
  65         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  66                 oparg = 1 << oparg;
  67
  68         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
  69                 return -EFAULT;
  70
  71         pagefault_disable();
  72         switch (op) {
  73         case FUTEX_OP_SET:
  74                 asm_ret = futex_set(uaddr, oparg);
  75                 break;
  76         case FUTEX_OP_ADD:
  77                 asm_ret = futex_add(uaddr, oparg);
  78                 break;
  79         case FUTEX_OP_OR:
  80                 asm_ret = futex_or(uaddr, oparg);
  81                 break;
  82         case FUTEX_OP_ANDN:
  83                 asm_ret = futex_andn(uaddr, oparg);
  84                 break;
  85         case FUTEX_OP_XOR:
  86                 asm_ret = futex_xor(uaddr, oparg);
  87                 break;
  88         default:
  89                 asm_ret.err = -ENOSYS;
  90         }
  91         pagefault_enable();
  92
  93         ret = asm_ret.err;
  94
  95         if (!ret) {
  96                 switch (cmp) {
  97                 case FUTEX_OP_CMP_EQ:
  98                         ret = (asm_ret.val == cmparg);
  99                         break;
 100                 case FUTEX_OP_CMP_NE:
 101                         ret = (asm_ret.val != cmparg);
 102                         break;
 103                 case FUTEX_OP_CMP_LT:
 104                         ret = (asm_ret.val < cmparg);
 105                         break;
 106                 case FUTEX_OP_CMP_GE:
 107                         ret = (asm_ret.val >= cmparg);
 108                         break;
 109                 case FUTEX_OP_CMP_LE:
 110                         ret = (asm_ret.val <= cmparg);
 111                         break;
 112                 case FUTEX_OP_CMP_GT:
 113                         ret = (asm_ret.val > cmparg);
 114                         break;
 115                 default:
 116                         ret = -ENOSYS;
 117                 }
 118         }
 119         return ret;
 120 }
 121
 122 static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
 123                                                 int newval)
 124 {
 125         struct __get_user asm_ret;
 126
 127         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 128                 return -EFAULT;
 129
 130         asm_ret = futex_cmpxchg(uaddr, oldval, newval);
 131         return asm_ret.err ? asm_ret.err : asm_ret.val;
 132 }
 133
 134 #endif /* !__ASSEMBLY__ */
 135
 136 #endif /* _ASM_TILE_FUTEX_H */