arch/loongarch/include/asm/futex.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
   4  */
   5 #ifndef _ASM_FUTEX_H
   6 #define _ASM_FUTEX_H
   7
   8 #include <linux/futex.h>
   9 #include <linux/uaccess.h>
  10 #include <asm/barrier.h>
  11 #include <asm/compiler.h>
  12 #include <asm/errno.h>
  13
  14 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)              \
  15 {                                                                       \
  16         __asm__ __volatile__(                                           \
  17         "1:     ll.w    %1, %4 # __futex_atomic_op\n"           \
  18         "       " insn  "                               \n"     \
  19         "2:     sc.w    $t0, %2                         \n"     \
  20         "       beq     $t0, $zero, 1b                  \n"     \
  21         "3:                                             \n"     \
  22         "       .section .fixup,\"ax\"                  \n"     \
  23         "4:     li.w    %0, %6                          \n"     \
  24         "       b       3b                              \n"     \
  25         "       .previous                               \n"     \
  26         "       .section __ex_table,\"a\"               \n"     \
  27         "       "__UA_ADDR "\t1b, 4b                    \n"     \
  28         "       "__UA_ADDR "\t2b, 4b                    \n"     \
  29         "       .previous                               \n"     \
  30         : "=r" (ret), "=&r" (oldval),                           \
  31           "=ZC" (*uaddr)                                        \
  32         : "0" (0), "ZC" (*uaddr), "Jr" (oparg),                 \
  33           "i" (-EFAULT)                                         \
  34         : "memory", "t0");                                      \
  35 }
  36
  37 static inline int
  38 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
  39 {
  40         int oldval = 0, ret = 0;
  41
  42         pagefault_disable();
  43
  44         switch (op) {
  45         case FUTEX_OP_SET:
  46                 __futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
  47                 break;
  48         case FUTEX_OP_ADD:
  49                 __futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
  50                 break;
  51         case FUTEX_OP_OR:
  52                 __futex_atomic_op("or   $t0, %1, %z5", ret, oldval, uaddr, oparg);
  53                 break;
  54         case FUTEX_OP_ANDN:
  55                 __futex_atomic_op("and  $t0, %1, %z5", ret, oldval, uaddr, ~oparg);
  56                 break;
  57         case FUTEX_OP_XOR:
  58                 __futex_atomic_op("xor  $t0, %1, %z5", ret, oldval, uaddr, oparg);
  59                 break;
  60         default:
  61                 ret = -ENOSYS;
  62         }
  63
  64         pagefault_enable();
  65
  66         if (!ret)
  67                 *oval = oldval;
  68
  69         return ret;
  70 }
  71
  72 static inline int
  73 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
  74 {
  75         int ret = 0;
  76         u32 val = 0;
  77
  78         if (!access_ok(uaddr, sizeof(u32)))
  79                 return -EFAULT;
  80
  81         __asm__ __volatile__(
  82         "# futex_atomic_cmpxchg_inatomic                        \n"
  83         "1:     ll.w    %1, %3                                  \n"
  84         "       bne     %1, %z4, 3f                             \n"
  85         "       or      $t0, %z5, $zero                         \n"
  86         "2:     sc.w    $t0, %2                                 \n"
  87         "       beq     $zero, $t0, 1b                          \n"
  88         "3:                                                     \n"
  89         __WEAK_LLSC_MB
  90         "       .section .fixup,\"ax\"                          \n"
  91         "4:     li.d    %0, %6                                  \n"
  92         "       b       3b                                      \n"
  93         "       .previous                                       \n"
  94         "       .section __ex_table,\"a\"                       \n"
  95         "       "__UA_ADDR "\t1b, 4b                            \n"
  96         "       "__UA_ADDR "\t2b, 4b                            \n"
  97         "       .previous                                       \n"
  98         : "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
  99         : GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
 100           "i" (-EFAULT)
 101         : "memory", "t0");
 102
 103         *uval = val;
 104
 105         return ret;
 106 }
 107
 108 #endif /* _ASM_FUTEX_H */