Linux Kernel  3.7.1
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futex.h
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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 */