arch/xtensa/include/asm/futex.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Atomic futex routines
   4  *
   5  * Based on the PowerPC implementataion
   6  *
   7  * Copyright (C) 2013 TangoTec Ltd.
   8  *
   9  * Baruch Siach <baruch@tkos.co.il>
  10  */
  11
  12 #ifndef _ASM_XTENSA_FUTEX_H
  13 #define _ASM_XTENSA_FUTEX_H
  14
  15 #include <linux/futex.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/errno.h>
  18
  19 #if XCHAL_HAVE_EXCLUSIVE
  20 #define __futex_atomic_op(insn, ret, old, uaddr, arg)   \
  21         __asm__ __volatile(                             \
  22         "1:     l32ex   %[oldval], %[addr]\n"           \
  23                 insn "\n"                               \
  24         "2:     s32ex   %[newval], %[addr]\n"           \
  25         "       getex   %[newval]\n"                    \
  26         "       beqz    %[newval], 1b\n"                \
  27         "       movi    %[newval], 0\n"                 \
  28         "3:\n"                                          \
  29         "       .section .fixup,\"ax\"\n"               \
  30         "       .align 4\n"                             \
  31         "       .literal_position\n"                    \
  32         "5:     movi    %[oldval], 3b\n"                \
  33         "       movi    %[newval], %[fault]\n"          \
  34         "       jx      %[oldval]\n"                    \
  35         "       .previous\n"                            \
  36         "       .section __ex_table,\"a\"\n"            \
  37         "       .long 1b, 5b, 2b, 5b\n"                 \
  38         "       .previous\n"                            \
  39         : [oldval] "=&r" (old), [newval] "=&r" (ret)    \
  40         : [addr] "r" (uaddr), [oparg] "r" (arg),        \
  41           [fault] "I" (-EFAULT)                         \
  42         : "memory")
  43 #elif XCHAL_HAVE_S32C1I
  44 #define __futex_atomic_op(insn, ret, old, uaddr, arg)   \
  45         __asm__ __volatile(                             \
  46         "1:     l32i    %[oldval], %[addr], 0\n"        \
  47                 insn "\n"                               \
  48         "       wsr     %[oldval], scompare1\n"         \
  49         "2:     s32c1i  %[newval], %[addr], 0\n"        \
  50         "       bne     %[newval], %[oldval], 1b\n"     \
  51         "       movi    %[newval], 0\n"                 \
  52         "3:\n"                                          \
  53         "       .section .fixup,\"ax\"\n"               \
  54         "       .align 4\n"                             \
  55         "       .literal_position\n"                    \
  56         "5:     movi    %[oldval], 3b\n"                \
  57         "       movi    %[newval], %[fault]\n"          \
  58         "       jx      %[oldval]\n"                    \
  59         "       .previous\n"                            \
  60         "       .section __ex_table,\"a\"\n"            \
  61         "       .long 1b, 5b, 2b, 5b\n"                 \
  62         "       .previous\n"                            \
  63         : [oldval] "=&r" (old), [newval] "=&r" (ret)    \
  64         : [addr] "r" (uaddr), [oparg] "r" (arg),        \
  65           [fault] "I" (-EFAULT)                         \
  66         : "memory")
  67 #endif
  68
  69 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
  70                 u32 __user *uaddr)
  71 {
  72 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
  73         int oldval = 0, ret;
  74
  75         pagefault_disable();
  76
  77         switch (op) {
  78         case FUTEX_OP_SET:
  79                 __futex_atomic_op("mov %[newval], %[oparg]",
  80                                   ret, oldval, uaddr, oparg);
  81                 break;
  82         case FUTEX_OP_ADD:
  83                 __futex_atomic_op("add %[newval], %[oldval], %[oparg]",
  84                                   ret, oldval, uaddr, oparg);
  85                 break;
  86         case FUTEX_OP_OR:
  87                 __futex_atomic_op("or %[newval], %[oldval], %[oparg]",
  88                                   ret, oldval, uaddr, oparg);
  89                 break;
  90         case FUTEX_OP_ANDN:
  91                 __futex_atomic_op("and %[newval], %[oldval], %[oparg]",
  92                                   ret, oldval, uaddr, ~oparg);
  93                 break;
  94         case FUTEX_OP_XOR:
  95                 __futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
  96                                   ret, oldval, uaddr, oparg);
  97                 break;
  98         default:
  99                 ret = -ENOSYS;
 100         }
 101
 102         pagefault_enable();
 103
 104         if (!ret)
 105                 *oval = oldval;
 106
 107         return ret;
 108 #else
 109         return -ENOSYS;
 110 #endif
 111 }
 112
 113 static inline int
 114 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 115                               u32 oldval, u32 newval)
 116 {
 117 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
 118         unsigned long tmp;
 119         int ret = 0;
 120
 121         if (!access_ok(uaddr, sizeof(u32)))
 122                 return -EFAULT;
 123
 124         __asm__ __volatile__ (
 125         "       # futex_atomic_cmpxchg_inatomic\n"
 126 #if XCHAL_HAVE_EXCLUSIVE
 127         "1:     l32ex   %[tmp], %[addr]\n"
 128         "       s32i    %[tmp], %[uval], 0\n"
 129         "       bne     %[tmp], %[oldval], 2f\n"
 130         "       mov     %[tmp], %[newval]\n"
 131         "3:     s32ex   %[tmp], %[addr]\n"
 132         "       getex   %[tmp]\n"
 133         "       beqz    %[tmp], 1b\n"
 134 #elif XCHAL_HAVE_S32C1I
 135         "       wsr     %[oldval], scompare1\n"
 136         "1:     s32c1i  %[newval], %[addr], 0\n"
 137         "       s32i    %[newval], %[uval], 0\n"
 138 #endif
 139         "2:\n"
 140         "       .section .fixup,\"ax\"\n"
 141         "       .align 4\n"
 142         "       .literal_position\n"
 143         "4:     movi    %[tmp], 2b\n"
 144         "       movi    %[ret], %[fault]\n"
 145         "       jx      %[tmp]\n"
 146         "       .previous\n"
 147         "       .section __ex_table,\"a\"\n"
 148         "       .long 1b, 4b\n"
 149 #if XCHAL_HAVE_EXCLUSIVE
 150         "       .long 3b, 4b\n"
 151 #endif
 152         "       .previous\n"
 153         : [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
 154         : [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
 155           [fault] "I" (-EFAULT)
 156         : "memory");
 157
 158         return ret;
 159 #else
 160         return -ENOSYS;
 161 #endif
 162 }
 163
 164 #endif /* _ASM_XTENSA_FUTEX_H */