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         ".section __ex_table,\"a\"\n" \
  27         ".align 3\n" \
  28         PPC_LONG "1b,4b,2b,4b\n" \
  29         ".previous" \
  30         : "=&r" (oldval), "=&r" (ret) \
  31         : "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
  32         : "cr0", "memory")
  33
  34 static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
  35 {
  36         int op = (encoded_op >> 28) & 7;
  37         int cmp = (encoded_op >> 24) & 15;
  38         int oparg = (encoded_op << 8) >> 20;
  39         int cmparg = (encoded_op << 20) >> 20;
  40         int oldval = 0, ret;
  41         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  42                 oparg = 1 << oparg;
  43
  44         if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
  45                 return -EFAULT;
  46
  47         pagefault_disable();
  48
  49         switch (op) {
  50         case FUTEX_OP_SET:
  51                 __futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
  52                 break;
  53         case FUTEX_OP_ADD:
  54                 __futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
  55                 break;
  56         case FUTEX_OP_OR:
  57                 __futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
  58                 break;
  59         case FUTEX_OP_ANDN:
  60                 __futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
  61                 break;
  62         case FUTEX_OP_XOR:
  63                 __futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
  64                 break;
  65         default:
  66                 ret = -ENOSYS;
  67         }
  68
  69         pagefault_enable();
  70
  71         if (!ret) {
  72                 switch (cmp) {
  73                 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
  74                 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
  75                 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
  76                 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
  77                 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
  78                 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
  79                 default: ret = -ENOSYS;
  80                 }
  81         }
  82         return ret;
  83 }
  84
  85 static inline int
  86 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
  87                               u32 oldval, u32 newval)
  88 {
  89         int ret = 0;
  90         u32 prev;
  91
  92         if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
  93                 return -EFAULT;
  94
  95         __asm__ __volatile__ (
  96         PPC_ATOMIC_ENTRY_BARRIER
  97 "1:     lwarx   %1,0,%3         # futex_atomic_cmpxchg_inatomic\n\
  98         cmpw    0,%1,%4\n\
  99         bne-    3f\n"
 100         PPC405_ERR77(0,%3)
 101 "2:     stwcx.  %5,0,%3\n\
 102         bne-    1b\n"
 103         PPC_ATOMIC_EXIT_BARRIER
 104 "3:     .section .fixup,\"ax\"\n\
 105 4:      li      %0,%6\n\
 106         b       3b\n\
 107         .previous\n\
 108         .section __ex_table,\"a\"\n\
 109         .align 3\n\
 110         " PPC_LONG "1b,4b,2b,4b\n\
 111         .previous" \
 112         : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
 113         : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
 114         : "cc", "memory");
 115
 116         *uval = prev;
 117         return ret;
 118 }
 119
 120 #endif /* __KERNEL__ */
 121 #endif /* _ASM_POWERPC_FUTEX_H */