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_RELEASE_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         "li     %1,0\n" \
  21 "3:     .section .fixup,\"ax\"\n" \
  22 "4:     li      %1,%3\n" \
  23         "b      3b\n" \
  24         ".previous\n" \
  25         ".section __ex_table,\"a\"\n" \
  26         ".align 3\n" \
  27         PPC_LONG "1b,4b,2b,4b\n" \
  28         ".previous" \
  29         : "=&r" (oldval), "=&r" (ret) \
  30         : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
  31         : "cr0", "memory")
  32
  33 static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
  34 {
  35         int op = (encoded_op >> 28) & 7;
  36         int cmp = (encoded_op >> 24) & 15;
  37         int oparg = (encoded_op << 8) >> 20;
  38         int cmparg = (encoded_op << 20) >> 20;
  39         int oldval = 0, ret;
  40         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  41                 oparg = 1 << oparg;
  42
  43         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
  44                 return -EFAULT;
  45
  46         pagefault_disable();
  47
  48         switch (op) {
  49         case FUTEX_OP_SET:
  50                 __futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
  51                 break;
  52         case FUTEX_OP_ADD:
  53                 __futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
  54                 break;
  55         case FUTEX_OP_OR:
  56                 __futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
  57                 break;
  58         case FUTEX_OP_ANDN:
  59                 __futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
  60                 break;
  61         case FUTEX_OP_XOR:
  62                 __futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
  63                 break;
  64         default:
  65                 ret = -ENOSYS;
  66         }
  67
  68         pagefault_enable();
  69
  70         if (!ret) {
  71                 switch (cmp) {
  72                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  73                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  74                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  75                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  76                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  77                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  78                 default: ret = -ENOSYS;
  79                 }
  80         }
  81         return ret;
  82 }
  83
  84 static inline int
  85 futex_atomic_cmpxchg_inatomic(int *uval, int __user *uaddr,
  86                               int oldval, int newval)
  87 {
  88         int ret = 0, prev;
  89
  90         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
  91                 return -EFAULT;
  92
  93         __asm__ __volatile__ (
  94         PPC_RELEASE_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_ACQUIRE_BARRIER
 102 "3:     .section .fixup,\"ax\"\n\
 103 4:      li      %0,%6\n\
 104         b       3b\n\
 105         .previous\n\
 106         .section __ex_table,\"a\"\n\
 107         .align 3\n\
 108         " PPC_LONG "1b,4b,2b,4b\n\
 109         .previous" \
 110         : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
 111         : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
 112         : "cc", "memory");
 113
 114         *uval = prev;
 115         return ret;
 116 }
 117
 118 #endif /* __KERNEL__ */
 119 #endif /* _ASM_POWERPC_FUTEX_H */