root/arch/alpha/include/asm/futex.h

INCLUDED FROM

DEFINITIONS

1. arch_futex_atomic_op_inuser
2. futex_atomic_cmpxchg_inatomic

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_ALPHA_FUTEX_H
   3 #define _ASM_ALPHA_FUTEX_H
   4 
   5 #ifdef __KERNEL__
   6 
   7 #include <linux/futex.h>
   8 #include <linux/uaccess.h>
   9 #include <asm/errno.h>
  10 #include <asm/barrier.h>
  11 
  12 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)      \
  13         __asm__ __volatile__(                                   \
  14                 __ASM_SMP_MB                                    \
  15         "1:     ldl_l   %0,0(%2)\n"                             \
  16                 insn                                            \
  17         "2:     stl_c   %1,0(%2)\n"                             \
  18         "       beq     %1,4f\n"                                \
  19         "       mov     $31,%1\n"                               \
  20         "3:     .subsection 2\n"                                \
  21         "4:     br      1b\n"                                   \
  22         "       .previous\n"                                    \
  23         EXC(1b,3b,$31,%1)                                       \
  24         EXC(2b,3b,$31,%1)                                       \
  25         :       "=&r" (oldval), "=&r"(ret)                      \
  26         :       "r" (uaddr), "r"(oparg)                         \
  27         :       "memory")
  28 
  29 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
  30                 u32 __user *uaddr)
  31 {
  32         int oldval = 0, ret;
  33 
  34         pagefault_disable();
  35 
  36         switch (op) {
  37         case FUTEX_OP_SET:
  38                 __futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
  39                 break;
  40         case FUTEX_OP_ADD:
  41                 __futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
  42                 break;
  43         case FUTEX_OP_OR:
  44                 __futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
  45                 break;
  46         case FUTEX_OP_ANDN:
  47                 __futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
  48                 break;
  49         case FUTEX_OP_XOR:
  50                 __futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
  51                 break;
  52         default:
  53                 ret = -ENOSYS;
  54         }
  55 
  56         pagefault_enable();
  57 
  58         if (!ret)
  59                 *oval = oldval;
  60 
  61         return ret;
  62 }
  63 
  64 static inline int
  65 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
  66                               u32 oldval, u32 newval)
  67 {
  68         int ret = 0, cmp;
  69         u32 prev;
  70 
  71         if (!access_ok(uaddr, sizeof(u32)))
  72                 return -EFAULT;
  73 
  74         __asm__ __volatile__ (
  75                 __ASM_SMP_MB
  76         "1:     ldl_l   %1,0(%3)\n"
  77         "       cmpeq   %1,%4,%2\n"
  78         "       beq     %2,3f\n"
  79         "       mov     %5,%2\n"
  80         "2:     stl_c   %2,0(%3)\n"
  81         "       beq     %2,4f\n"
  82         "3:     .subsection 2\n"
  83         "4:     br      1b\n"
  84         "       .previous\n"
  85         EXC(1b,3b,$31,%0)
  86         EXC(2b,3b,$31,%0)
  87         :       "+r"(ret), "=&r"(prev), "=&r"(cmp)
  88         :       "r"(uaddr), "r"((long)(int)oldval), "r"(newval)
  89         :       "memory");
  90 
  91         *uval = prev;
  92         return ret;
  93 }
  94 
  95 #endif /* __KERNEL__ */
  96 #endif /* _ASM_ALPHA_FUTEX_H */