arch/unicore32/include/asm/futex.h

   1 /*
   2  * linux/arch/unicore32/include/asm/futex.h
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #ifndef __UNICORE_FUTEX_H__
  14 #define __UNICORE_FUTEX_H__
  15
  16 #ifdef __KERNEL__
  17
  18 #include <linux/futex.h>
  19 #include <linux/preempt.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/errno.h>
  22
  23 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)      \
  24         __asm__ __volatile__(                                   \
  25         "1:     ldw.u   %1, [%2]\n"                             \
  26         "       " insn "\n"                                     \
  27         "2:     stw.u   %0, [%2]\n"                             \
  28         "       mov     %0, #0\n"                               \
  29         "3:\n"                                                  \
  30         "       .pushsection __ex_table,\"a\"\n"                \
  31         "       .align  3\n"                                    \
  32         "       .long   1b, 4f, 2b, 4f\n"                       \
  33         "       .popsection\n"                                  \
  34         "       .pushsection .fixup,\"ax\"\n"                   \
  35         "4:     mov     %0, %4\n"                               \
  36         "       b       3b\n"                                   \
  37         "       .popsection"                                    \
  38         : "=&r" (ret), "=&r" (oldval)                           \
  39         : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT)              \
  40         : "cc", "memory")
  41
  42 static inline int
  43 futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
  44 {
  45         int op = (encoded_op >> 28) & 7;
  46         int cmp = (encoded_op >> 24) & 15;
  47         int oparg = (encoded_op << 8) >> 20;
  48         int cmparg = (encoded_op << 20) >> 20;
  49         int oldval = 0, ret;
  50
  51         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  52                 oparg = 1 << oparg;
  53
  54         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
  55                 return -EFAULT;
  56
  57         pagefault_disable();    /* implies preempt_disable() */
  58
  59         switch (op) {
  60         case FUTEX_OP_SET:
  61                 __futex_atomic_op("mov  %0, %3", ret, oldval, uaddr, oparg);
  62                 break;
  63         case FUTEX_OP_ADD:
  64                 __futex_atomic_op("add  %0, %1, %3", ret, oldval, uaddr, oparg);
  65                 break;
  66         case FUTEX_OP_OR:
  67                 __futex_atomic_op("or   %0, %1, %3", ret, oldval, uaddr, oparg);
  68                 break;
  69         case FUTEX_OP_ANDN:
  70                 __futex_atomic_op("and  %0, %1, %3",
  71                                 ret, oldval, uaddr, ~oparg);
  72                 break;
  73         case FUTEX_OP_XOR:
  74                 __futex_atomic_op("xor  %0, %1, %3", ret, oldval, uaddr, oparg);
  75                 break;
  76         default:
  77                 ret = -ENOSYS;
  78         }
  79
  80         pagefault_enable();     /* subsumes preempt_enable() */
  81
  82         if (!ret) {
  83                 switch (cmp) {
  84                 case FUTEX_OP_CMP_EQ:
  85                         ret = (oldval == cmparg);
  86                         break;
  87                 case FUTEX_OP_CMP_NE:
  88                         ret = (oldval != cmparg);
  89                         break;
  90                 case FUTEX_OP_CMP_LT:
  91                         ret = (oldval <  cmparg);
  92                         break;
  93                 case FUTEX_OP_CMP_GE:
  94                         ret = (oldval >= cmparg);
  95                         break;
  96                 case FUTEX_OP_CMP_LE:
  97                         ret = (oldval <= cmparg);
  98                         break;
  99                 case FUTEX_OP_CMP_GT:
 100                         ret = (oldval >  cmparg);
 101                         break;
 102                 default:
 103                         ret = -ENOSYS;
 104                 }
 105         }
 106         return ret;
 107 }
 108
 109 static inline int
 110 futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 111 {
 112         int val;
 113
 114         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 115                 return -EFAULT;
 116
 117         pagefault_disable();    /* implies preempt_disable() */
 118
 119         __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
 120         "1:     ldw.u   %0, [%3]\n"
 121         "       cmpxor.a        %0, %1\n"
 122         "       bne     3f\n"
 123         "2:     stw.u   %2, [%3]\n"
 124         "3:\n"
 125         "       .pushsection __ex_table,\"a\"\n"
 126         "       .align  3\n"
 127         "       .long   1b, 4f, 2b, 4f\n"
 128         "       .popsection\n"
 129         "       .pushsection .fixup,\"ax\"\n"
 130         "4:     mov     %0, %4\n"
 131         "       b       3b\n"
 132         "       .popsection"
 133         : "=&r" (val)
 134         : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
 135         : "cc", "memory");
 136
 137         pagefault_enable();     /* subsumes preempt_enable() */
 138
 139         return val;
 140 }
 141
 142 #endif /* __KERNEL__ */
 143 #endif /* __UNICORE_FUTEX_H__ */