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 #define arch_futex_atomic_op_inuser arch_futex_atomic_op_inuser
  20 #define futex_atomic_cmpxchg_inatomic futex_atomic_cmpxchg_inatomic
  21 #include <asm-generic/futex.h>
  22
  23 #if XCHAL_HAVE_EXCLUSIVE
  24 #define __futex_atomic_op(insn, ret, old, uaddr, arg)   \
  25         __asm__ __volatile(                             \
  26         "1:     l32ex   %[oldval], %[addr]\n"           \
  27                 insn "\n"                               \
  28         "2:     s32ex   %[newval], %[addr]\n"           \
  29         "       getex   %[newval]\n"                    \
  30         "       beqz    %[newval], 1b\n"                \
  31         "       movi    %[newval], 0\n"                 \
  32         "3:\n"                                          \
  33         "       .section .fixup,\"ax\"\n"               \
  34         "       .align 4\n"                             \
  35         "       .literal_position\n"                    \
  36         "5:     movi    %[oldval], 3b\n"                \
  37         "       movi    %[newval], %[fault]\n"          \
  38         "       jx      %[oldval]\n"                    \
  39         "       .previous\n"                            \
  40         "       .section __ex_table,\"a\"\n"            \
  41         "       .long 1b, 5b, 2b, 5b\n"                 \
  42         "       .previous\n"                            \
  43         : [oldval] "=&r" (old), [newval] "=&r" (ret)    \
  44         : [addr] "r" (uaddr), [oparg] "r" (arg),        \
  45           [fault] "I" (-EFAULT)                         \
  46         : "memory")
  47 #elif XCHAL_HAVE_S32C1I
  48 #define __futex_atomic_op(insn, ret, old, uaddr, arg)   \
  49         __asm__ __volatile(                             \
  50         "1:     l32i    %[oldval], %[mem]\n"            \
  51                 insn "\n"                               \
  52         "       wsr     %[oldval], scompare1\n"         \
  53         "2:     s32c1i  %[newval], %[mem]\n"            \
  54         "       bne     %[newval], %[oldval], 1b\n"     \
  55         "       movi    %[newval], 0\n"                 \
  56         "3:\n"                                          \
  57         "       .section .fixup,\"ax\"\n"               \
  58         "       .align 4\n"                             \
  59         "       .literal_position\n"                    \
  60         "5:     movi    %[oldval], 3b\n"                \
  61         "       movi    %[newval], %[fault]\n"          \
  62         "       jx      %[oldval]\n"                    \
  63         "       .previous\n"                            \
  64         "       .section __ex_table,\"a\"\n"            \
  65         "       .long 1b, 5b, 2b, 5b\n"                 \
  66         "       .previous\n"                            \
  67         : [oldval] "=&r" (old), [newval] "=&r" (ret),   \
  68           [mem] "+m" (*(uaddr))                         \
  69         : [oparg] "r" (arg), [fault] "I" (-EFAULT)      \
  70         : "memory")
  71 #endif
  72
  73 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
  74                 u32 __user *uaddr)
  75 {
  76 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
  77         int oldval = 0, ret;
  78
  79         if (!access_ok(uaddr, sizeof(u32)))
  80                 return -EFAULT;
  81
  82         switch (op) {
  83         case FUTEX_OP_SET:
  84                 __futex_atomic_op("mov %[newval], %[oparg]",
  85                                   ret, oldval, uaddr, oparg);
  86                 break;
  87         case FUTEX_OP_ADD:
  88                 __futex_atomic_op("add %[newval], %[oldval], %[oparg]",
  89                                   ret, oldval, uaddr, oparg);
  90                 break;
  91         case FUTEX_OP_OR:
  92                 __futex_atomic_op("or %[newval], %[oldval], %[oparg]",
  93                                   ret, oldval, uaddr, oparg);
  94                 break;
  95         case FUTEX_OP_ANDN:
  96                 __futex_atomic_op("and %[newval], %[oldval], %[oparg]",
  97                                   ret, oldval, uaddr, ~oparg);
  98                 break;
  99         case FUTEX_OP_XOR:
 100                 __futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
 101                                   ret, oldval, uaddr, oparg);
 102                 break;
 103         default:
 104                 ret = -ENOSYS;
 105         }
 106
 107         if (!ret)
 108                 *oval = oldval;
 109
 110         return ret;
 111 #else
 112         return futex_atomic_op_inuser_local(op, oparg, oval, uaddr);
 113 #endif
 114 }
 115
 116 static inline int
 117 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 118                               u32 oldval, u32 newval)
 119 {
 120 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
 121         unsigned long tmp;
 122         int ret = 0;
 123
 124         if (!access_ok(uaddr, sizeof(u32)))
 125                 return -EFAULT;
 126
 127         __asm__ __volatile__ (
 128         "       # futex_atomic_cmpxchg_inatomic\n"
 129 #if XCHAL_HAVE_EXCLUSIVE
 130         "1:     l32ex   %[tmp], %[addr]\n"
 131         "       s32i    %[tmp], %[uval], 0\n"
 132         "       bne     %[tmp], %[oldval], 2f\n"
 133         "       mov     %[tmp], %[newval]\n"
 134         "3:     s32ex   %[tmp], %[addr]\n"
 135         "       getex   %[tmp]\n"
 136         "       beqz    %[tmp], 1b\n"
 137 #elif XCHAL_HAVE_S32C1I
 138         "       wsr     %[oldval], scompare1\n"
 139         "1:     s32c1i  %[newval], %[addr], 0\n"
 140         "       s32i    %[newval], %[uval], 0\n"
 141 #endif
 142         "2:\n"
 143         "       .section .fixup,\"ax\"\n"
 144         "       .align 4\n"
 145         "       .literal_position\n"
 146         "4:     movi    %[tmp], 2b\n"
 147         "       movi    %[ret], %[fault]\n"
 148         "       jx      %[tmp]\n"
 149         "       .previous\n"
 150         "       .section __ex_table,\"a\"\n"
 151         "       .long 1b, 4b\n"
 152 #if XCHAL_HAVE_EXCLUSIVE
 153         "       .long 3b, 4b\n"
 154 #endif
 155         "       .previous\n"
 156         : [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
 157         : [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
 158           [fault] "I" (-EFAULT)
 159         : "memory");
 160
 161         return ret;
 162 #else
 163         return futex_atomic_cmpxchg_inatomic_local(uval, uaddr, oldval, newval);
 164 #endif
 165 }
 166
 167 #endif /* _ASM_XTENSA_FUTEX_H */