arch/xtensa/include/asm/futex.h

   1 /*
   2  * Atomic futex routines
   3  *
   4  * Based on the PowerPC implementataion
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Copyright (C) 2013 TangoTec Ltd.
  11  *
  12  * Baruch Siach <baruch@tkos.co.il>
  13  */
  14
  15 #ifndef _ASM_XTENSA_FUTEX_H
  16 #define _ASM_XTENSA_FUTEX_H
  17
  18 #include <linux/futex.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/errno.h>
  21
  22 #if XCHAL_HAVE_EXCLUSIVE
  23 #define __futex_atomic_op(insn, ret, old, uaddr, arg)   \
  24         __asm__ __volatile(                             \
  25         "1:     l32ex   %[oldval], %[addr]\n"           \
  26                 insn "\n"                               \
  27         "2:     s32ex   %[newval], %[addr]\n"           \
  28         "       getex   %[newval]\n"                    \
  29         "       beqz    %[newval], 1b\n"                \
  30         "       movi    %[newval], 0\n"                 \
  31         "3:\n"                                          \
  32         "       .section .fixup,\"ax\"\n"               \
  33         "       .align 4\n"                             \
  34         "       .literal_position\n"                    \
  35         "5:     movi    %[oldval], 3b\n"                \
  36         "       movi    %[newval], %[fault]\n"          \
  37         "       jx      %[oldval]\n"                    \
  38         "       .previous\n"                            \
  39         "       .section __ex_table,\"a\"\n"            \
  40         "       .long 1b, 5b, 2b, 5b\n"                 \
  41         "       .previous\n"                            \
  42         : [oldval] "=&r" (old), [newval] "=&r" (ret)    \
  43         : [addr] "r" (uaddr), [oparg] "r" (arg),        \
  44           [fault] "I" (-EFAULT)                         \
  45         : "memory")
  46 #elif XCHAL_HAVE_S32C1I
  47 #define __futex_atomic_op(insn, ret, old, uaddr, arg)   \
  48         __asm__ __volatile(                             \
  49         "1:     l32i    %[oldval], %[addr], 0\n"        \
  50                 insn "\n"                               \
  51         "       wsr     %[oldval], scompare1\n"         \
  52         "2:     s32c1i  %[newval], %[addr], 0\n"        \
  53         "       bne     %[newval], %[oldval], 1b\n"     \
  54         "       movi    %[newval], 0\n"                 \
  55         "3:\n"                                          \
  56         "       .section .fixup,\"ax\"\n"               \
  57         "       .align 4\n"                             \
  58         "       .literal_position\n"                    \
  59         "5:     movi    %[oldval], 3b\n"                \
  60         "       movi    %[newval], %[fault]\n"          \
  61         "       jx      %[oldval]\n"                    \
  62         "       .previous\n"                            \
  63         "       .section __ex_table,\"a\"\n"            \
  64         "       .long 1b, 5b, 2b, 5b\n"                 \
  65         "       .previous\n"                            \
  66         : [oldval] "=&r" (old), [newval] "=&r" (ret)    \
  67         : [addr] "r" (uaddr), [oparg] "r" (arg),        \
  68           [fault] "I" (-EFAULT)                         \
  69         : "memory")
  70 #endif
  71
  72 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
  73                 u32 __user *uaddr)
  74 {
  75 #if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
  76         int oldval = 0, ret;
  77
  78         pagefault_disable();
  79
  80         switch (op) {
  81         case FUTEX_OP_SET:
  82                 __futex_atomic_op("mov %[newval], %[oparg]",
  83                                   ret, oldval, uaddr, oparg);
  84                 break;
  85         case FUTEX_OP_ADD:
  86                 __futex_atomic_op("add %[newval], %[oldval], %[oparg]",
  87                                   ret, oldval, uaddr, oparg);
  88                 break;
  89         case FUTEX_OP_OR:
  90                 __futex_atomic_op("or %[newval], %[oldval], %[oparg]",
  91                                   ret, oldval, uaddr, oparg);
  92                 break;
  93         case FUTEX_OP_ANDN:
  94                 __futex_atomic_op("and %[newval], %[oldval], %[oparg]",
  95                                   ret, oldval, uaddr, ~oparg);
  96                 break;
  97         case FUTEX_OP_XOR:
  98                 __futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
  99                                   ret, oldval, uaddr, oparg);
 100                 break;
 101         default:
 102                 ret = -ENOSYS;
 103         }
 104
 105         pagefault_enable();
 106
 107         if (!ret)
 108                 *oval = oldval;
 109
 110         return ret;
 111 #else
 112         return -ENOSYS;
 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 -ENOSYS;
 164 #endif
 165 }
 166
 167 #endif /* _ASM_XTENSA_FUTEX_H */