arch/nds32/include/asm/futex.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4 #ifndef __NDS32_FUTEX_H__
   5 #define __NDS32_FUTEX_H__
   6
   7 #include <linux/futex.h>
   8 #include <linux/uaccess.h>
   9 #include <asm/errno.h>
  10
  11 #define __futex_atomic_ex_table(err_reg)                        \
  12         "       .pushsection __ex_table,\"a\"\n"                \
  13         "       .align  3\n"                                    \
  14         "       .long   1b, 4f\n"                               \
  15         "       .long   2b, 4f\n"                               \
  16         "       .popsection\n"                                  \
  17         "       .pushsection .fixup,\"ax\"\n"                   \
  18         "4:     move    %0, " err_reg "\n"                      \
  19         "       b       3b\n"                                   \
  20         "       .popsection"
  21
  22 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
  23         smp_mb();                                               \
  24         asm volatile(                                   \
  25         "       movi    $ta, #0\n"                              \
  26         "1:     llw     %1, [%2+$ta]\n"                         \
  27         "       " insn "\n"                                     \
  28         "2:     scw     %0, [%2+$ta]\n"                         \
  29         "       beqz    %0, 1b\n"                               \
  30         "       movi    %0, #0\n"                               \
  31         "3:\n"                                                  \
  32         __futex_atomic_ex_table("%4")                           \
  33         : "=&r" (ret), "=&r" (oldval)                           \
  34         : "r" (uaddr), "r" (oparg), "i" (-EFAULT)               \
  35         : "cc", "memory")
  36 static inline int
  37 futex_atomic_cmpxchg_inatomic(u32 * uval, u32 __user * uaddr,
  38                               u32 oldval, u32 newval)
  39 {
  40         int ret = 0;
  41         u32 val, tmp, flags;
  42
  43         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  44                 return -EFAULT;
  45
  46         smp_mb();
  47         asm volatile ("       movi    $ta, #0\n"
  48                       "1:     llw     %1, [%6 + $ta]\n"
  49                       "       sub     %3, %1, %4\n"
  50                       "       cmovz   %2, %5, %3\n"
  51                       "       cmovn   %2, %1, %3\n"
  52                       "2:     scw     %2, [%6 + $ta]\n"
  53                       "       beqz    %2, 1b\n"
  54                       "3:\n                   " __futex_atomic_ex_table("%7")
  55                       :"+&r"(ret), "=&r"(val), "=&r"(tmp), "=&r"(flags)
  56                       :"r"(oldval), "r"(newval), "r"(uaddr), "i"(-EFAULT)
  57                       :"$ta", "memory");
  58         smp_mb();
  59
  60         *uval = val;
  61         return ret;
  62 }
  63
  64 static inline int
  65 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
  66 {
  67         int oldval = 0, ret;
  68
  69
  70         pagefault_disable();
  71         switch (op) {
  72         case FUTEX_OP_SET:
  73                 __futex_atomic_op("move %0, %3", ret, oldval, tmp, uaddr,
  74                                   oparg);
  75                 break;
  76         case FUTEX_OP_ADD:
  77                 __futex_atomic_op("add  %0, %1, %3", ret, oldval, tmp, uaddr,
  78                                   oparg);
  79                 break;
  80         case FUTEX_OP_OR:
  81                 __futex_atomic_op("or   %0, %1, %3", ret, oldval, tmp, uaddr,
  82                                   oparg);
  83                 break;
  84         case FUTEX_OP_ANDN:
  85                 __futex_atomic_op("and  %0, %1, %3", ret, oldval, tmp, uaddr,
  86                                   ~oparg);
  87                 break;
  88         case FUTEX_OP_XOR:
  89                 __futex_atomic_op("xor  %0, %1, %3", ret, oldval, tmp, uaddr,
  90                                   oparg);
  91                 break;
  92         default:
  93                 ret = -ENOSYS;
  94         }
  95
  96         pagefault_enable();
  97
  98         if (!ret)
  99                 *oval = oldval;
 100
 101         return ret;
 102 }
 103 #endif /* __NDS32_FUTEX_H__ */