include/asm-s390/futex.h

   1 #ifndef _ASM_S390_FUTEX_H
   2 #define _ASM_S390_FUTEX_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/futex.h>
   7 #include <asm/errno.h>
   8 #include <asm/uaccess.h>
   9
  10 #ifndef __s390x__
  11 #define __futex_atomic_fixup \
  12                      ".section __ex_table,\"a\"\n"                      \
  13                      "   .align 4\n"                                    \
  14                      "   .long  0b,4b,2b,4b,3b,4b\n"                    \
  15                      ".previous"
  16 #else /* __s390x__ */
  17 #define __futex_atomic_fixup \
  18                      ".section __ex_table,\"a\"\n"                      \
  19                      "   .align 8\n"                                    \
  20                      "   .quad  0b,4b,2b,4b,3b,4b\n"                    \
  21                      ".previous"
  22 #endif /* __s390x__ */
  23
  24 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)      \
  25         asm volatile("   sacf 256\n"                                    \
  26                      "0: l   %1,0(%6)\n"                                \
  27                      "1: " insn                                         \
  28                      "2: cs  %1,%2,0(%6)\n"                             \
  29                      "3: jl  1b\n"                                      \
  30                      "   lhi %0,0\n"                                    \
  31                      "4: sacf 0\n"                                      \
  32                      __futex_atomic_fixup                               \
  33                      : "=d" (ret), "=&d" (oldval), "=&d" (newval),      \
  34                        "=m" (*uaddr)                                    \
  35                      : "0" (-EFAULT), "d" (oparg), "a" (uaddr),         \
  36                        "m" (*uaddr) : "cc" );
  37
  38 static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  39 {
  40         int op = (encoded_op >> 28) & 7;
  41         int cmp = (encoded_op >> 24) & 15;
  42         int oparg = (encoded_op << 8) >> 20;
  43         int cmparg = (encoded_op << 20) >> 20;
  44         int oldval = 0, newval, ret;
  45         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  46                 oparg = 1 << oparg;
  47
  48         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  49                 return -EFAULT;
  50
  51         inc_preempt_count();
  52
  53         switch (op) {
  54         case FUTEX_OP_SET:
  55                 __futex_atomic_op("lr %2,%5\n",
  56                                   ret, oldval, newval, uaddr, oparg);
  57                 break;
  58         case FUTEX_OP_ADD:
  59                 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
  60                                   ret, oldval, newval, uaddr, oparg);
  61                 break;
  62         case FUTEX_OP_OR:
  63                 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
  64                                   ret, oldval, newval, uaddr, oparg);
  65                 break;
  66         case FUTEX_OP_ANDN:
  67                 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
  68                                   ret, oldval, newval, uaddr, oparg);
  69                 break;
  70         case FUTEX_OP_XOR:
  71                 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
  72                                   ret, oldval, newval, uaddr, oparg);
  73                 break;
  74         default:
  75                 ret = -ENOSYS;
  76         }
  77
  78         dec_preempt_count();
  79
  80         if (!ret) {
  81                 switch (cmp) {
  82                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  83                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  84                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  85                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  86                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  87                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  88                 default: ret = -ENOSYS;
  89                 }
  90         }
  91         return ret;
  92 }
  93
  94 static inline int
  95 futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
  96 {
  97         int ret;
  98
  99         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
 100                 return -EFAULT;
 101         asm volatile("   sacf 256\n"
 102                      "   cs   %1,%4,0(%5)\n"
 103                      "0: lr   %0,%1\n"
 104                      "1: sacf 0\n"
 105 #ifndef __s390x__
 106                      ".section __ex_table,\"a\"\n"
 107                      "   .align 4\n"
 108                      "   .long  0b,1b\n"
 109                      ".previous"
 110 #else /* __s390x__ */
 111                      ".section __ex_table,\"a\"\n"
 112                      "   .align 8\n"
 113                      "   .quad  0b,1b\n"
 114                      ".previous"
 115 #endif /* __s390x__ */
 116                      : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
 117                      : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
 118                      : "cc", "memory" );
 119         return oldval;
 120 }
 121
 122 #endif /* __KERNEL__ */
 123 #endif /* _ASM_S390_FUTEX_H */