root/arch/s390/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_S390_FUTEX_H
   3 #define _ASM_S390_FUTEX_H
   4 
   5 #include <linux/uaccess.h>
   6 #include <linux/futex.h>
   7 #include <asm/mmu_context.h>
   8 #include <asm/errno.h>
   9 
  10 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
  11         asm volatile(                                                   \
  12                 "   sacf  256\n"                                        \
  13                 "0: l     %1,0(%6)\n"                                   \
  14                 "1:"insn                                                \
  15                 "2: cs    %1,%2,0(%6)\n"                                \
  16                 "3: jl    1b\n"                                         \
  17                 "   lhi   %0,0\n"                                       \
  18                 "4: sacf  768\n"                                        \
  19                 EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b)         \
  20                 : "=d" (ret), "=&d" (oldval), "=&d" (newval),           \
  21                   "=m" (*uaddr)                                         \
  22                 : "0" (-EFAULT), "d" (oparg), "a" (uaddr),              \
  23                   "m" (*uaddr) : "cc");
  24 
  25 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
  26                 u32 __user *uaddr)
  27 {
  28         int oldval = 0, newval, ret;
  29         mm_segment_t old_fs;
  30 
  31         old_fs = enable_sacf_uaccess();
  32         pagefault_disable();
  33         switch (op) {
  34         case FUTEX_OP_SET:
  35                 __futex_atomic_op("lr %2,%5\n",
  36                                   ret, oldval, newval, uaddr, oparg);
  37                 break;
  38         case FUTEX_OP_ADD:
  39                 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
  40                                   ret, oldval, newval, uaddr, oparg);
  41                 break;
  42         case FUTEX_OP_OR:
  43                 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
  44                                   ret, oldval, newval, uaddr, oparg);
  45                 break;
  46         case FUTEX_OP_ANDN:
  47                 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
  48                                   ret, oldval, newval, uaddr, oparg);
  49                 break;
  50         case FUTEX_OP_XOR:
  51                 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
  52                                   ret, oldval, newval, uaddr, oparg);
  53                 break;
  54         default:
  55                 ret = -ENOSYS;
  56         }
  57         pagefault_enable();
  58         disable_sacf_uaccess(old_fs);
  59 
  60         if (!ret)
  61                 *oval = oldval;
  62 
  63         return ret;
  64 }
  65 
  66 static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
  67                                                 u32 oldval, u32 newval)
  68 {
  69         mm_segment_t old_fs;
  70         int ret;
  71 
  72         old_fs = enable_sacf_uaccess();
  73         asm volatile(
  74                 "   sacf 256\n"
  75                 "0: cs   %1,%4,0(%5)\n"
  76                 "1: la   %0,0\n"
  77                 "2: sacf 768\n"
  78                 EX_TABLE(0b,2b) EX_TABLE(1b,2b)
  79                 : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
  80                 : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
  81                 : "cc", "memory");
  82         disable_sacf_uaccess(old_fs);
  83         *uval = oldval;
  84         return ret;
  85 }
  86 
  87 #endif /* _ASM_S390_FUTEX_H */