arch/powerpc/include/asm/futex.h

   1 #ifndef _ASM_POWERPC_FUTEX_H
   2 #define _ASM_POWERPC_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/synch.h>
  10 #include <asm/asm-compat.h>
  11
  12 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
  13   __asm__ __volatile ( \
  14         PPC_ATOMIC_ENTRY_BARRIER \
  15 "1:     lwarx   %0,0,%2\n" \
  16         insn \
  17         PPC405_ERR77(0, %2) \
  18 "2:     stwcx.  %1,0,%2\n" \
  19         "bne-   1b\n" \
  20         PPC_ATOMIC_EXIT_BARRIER \
  21         "li     %1,0\n" \
  22 "3:     .section .fixup,\"ax\"\n" \
  23 "4:     li      %1,%3\n" \
  24         "b      3b\n" \
  25         ".previous\n" \
  26         EX_TABLE(1b, 4b) \
  27         EX_TABLE(2b, 4b) \
  28         : "=&r" (oldval), "=&r" (ret) \
  29         : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
  30         : "cr0", "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("mr %1,%4\n", ret, oldval, uaddr, oparg);
  50                 break;
  51         case FUTEX_OP_ADD:
  52                 __futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
  53                 break;
  54         case FUTEX_OP_OR:
  55                 __futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
  56                 break;
  57         case FUTEX_OP_ANDN:
  58                 __futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
  59                 break;
  60         case FUTEX_OP_XOR:
  61                 __futex_atomic_op("xor %1,%0,%4\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;
  88         u32 prev;
  89
  90         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  91                 return -EFAULT;
  92
  93         __asm__ __volatile__ (
  94         PPC_ATOMIC_ENTRY_BARRIER
  95 "1:     lwarx   %1,0,%3         # futex_atomic_cmpxchg_inatomic\n\
  96         cmpw    0,%1,%4\n\
  97         bne-    3f\n"
  98         PPC405_ERR77(0,%3)
  99 "2:     stwcx.  %5,0,%3\n\
 100         bne-    1b\n"
 101         PPC_ATOMIC_EXIT_BARRIER
 102 "3:     .section .fixup,\"ax\"\n\
 103 4:      li      %0,%6\n\
 104         b       3b\n\
 105         .previous\n"
 106         EX_TABLE(1b, 4b)
 107         EX_TABLE(2b, 4b)
 108         : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
 109         : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
 110         : "cc", "memory");
 111
 112         *uval = prev;
 113         return ret;
 114 }
 115
 116 #endif /* __KERNEL__ */
 117 #endif /* _ASM_POWERPC_FUTEX_H */