arch/alpha/include/asm/futex.h

   1 #ifndef _ASM_ALPHA_FUTEX_H
   2 #define _ASM_ALPHA_FUTEX_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/futex.h>
   7 #include <linux/uaccess.h>
   8 #include <asm/errno.h>
   9 #include <asm/barrier.h>
  10
  11 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)      \
  12         __asm__ __volatile__(                                   \
  13                 __ASM_SMP_MB                                    \
  14         "1:     ldl_l   %0,0(%2)\n"                             \
  15                 insn                                            \
  16         "2:     stl_c   %1,0(%2)\n"                             \
  17         "       beq     %1,4f\n"                                \
  18         "       mov     $31,%1\n"                               \
  19         "3:     .subsection 2\n"                                \
  20         "4:     br      1b\n"                                   \
  21         "       .previous\n"                                    \
  22         "       .section __ex_table,\"a\"\n"                    \
  23         "       .long   1b-.\n"                                 \
  24         "       lda     $31,3b-1b(%1)\n"                        \
  25         "       .long   2b-.\n"                                 \
  26         "       lda     $31,3b-2b(%1)\n"                        \
  27         "       .previous\n"                                    \
  28         :       "=&r" (oldval), "=&r"(ret)                      \
  29         :       "r" (uaddr), "r"(oparg)                         \
  30         :       "memory")
  31
  32 static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
  33 {
  34         int op = (encoded_op >> 28) & 7;
  35         int cmp = (encoded_op >> 24) & 15;
  36         int oparg = (encoded_op << 8) >> 20;
  37         int cmparg = (encoded_op << 20) >> 20;
  38         int oldval = 0, ret;
  39         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  40                 oparg = 1 << oparg;
  41
  42         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  43                 return -EFAULT;
  44
  45         pagefault_disable();
  46
  47         switch (op) {
  48         case FUTEX_OP_SET:
  49                 __futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
  50                 break;
  51         case FUTEX_OP_ADD:
  52                 __futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
  53                 break;
  54         case FUTEX_OP_OR:
  55                 __futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
  56                 break;
  57         case FUTEX_OP_ANDN:
  58                 __futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
  59                 break;
  60         case FUTEX_OP_XOR:
  61                 __futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
  62                 break;
  63         default:
  64                 ret = -ENOSYS;
  65         }
  66
  67         pagefault_enable();
  68
  69         if (!ret) {
  70                 switch (cmp) {
  71                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  72                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  73                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  74                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  75                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  76                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  77                 default: ret = -ENOSYS;
  78                 }
  79         }
  80         return ret;
  81 }
  82
  83 static inline int
  84 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
  85                               u32 oldval, u32 newval)
  86 {
  87         int ret = 0, cmp;
  88         u32 prev;
  89
  90         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  91                 return -EFAULT;
  92
  93         __asm__ __volatile__ (
  94                 __ASM_SMP_MB
  95         "1:     ldl_l   %1,0(%3)\n"
  96         "       cmpeq   %1,%4,%2\n"
  97         "       beq     %2,3f\n"
  98         "       mov     %5,%2\n"
  99         "2:     stl_c   %2,0(%3)\n"
 100         "       beq     %2,4f\n"
 101         "3:     .subsection 2\n"
 102         "4:     br      1b\n"
 103         "       .previous\n"
 104         "       .section __ex_table,\"a\"\n"
 105         "       .long   1b-.\n"
 106         "       lda     $31,3b-1b(%0)\n"
 107         "       .long   2b-.\n"
 108         "       lda     $31,3b-2b(%0)\n"
 109         "       .previous\n"
 110         :       "+r"(ret), "=&r"(prev), "=&r"(cmp)
 111         :       "r"(uaddr), "r"((long)(int)oldval), "r"(newval)
 112         :       "memory");
 113
 114         *uval = prev;
 115         return ret;
 116 }
 117
 118 #endif /* __KERNEL__ */
 119 #endif /* _ASM_ALPHA_FUTEX_H */