1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
#ifndef _ASM_ARM_FUTEX_H
#define _ASM_ARM_FUTEX_H
#ifdef __KERNEL__
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#define __futex_atomic_ex_table(err_reg) \
"3:\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
" .long 1b, 4f, 2b, 4f\n" \
" .popsection\n" \
" .pushsection .text.fixup,\"ax\"\n" \
" .align 2\n" \
"4: mov %0, " err_reg "\n" \
" b 3b\n" \
" .popsection"
#ifdef CONFIG_SMP
#define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
smp_mb(); \
prefetchw(uaddr); \
__asm__ __volatile__( \
"1: ldrex %1, [%3]\n" \
" " insn "\n" \
"2: strex %2, %0, [%3]\n" \
" teq %2, #0\n" \
" bne 1b\n" \
" mov %0, #0\n" \
__futex_atomic_ex_table("%5") \
: "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \
: "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \
: "cc", "memory")
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret;
u32 val;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
smp_mb();
/* Prefetching cannot fault */
prefetchw(uaddr);
__asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
"1: ldrex %1, [%4]\n"
" teq %1, %2\n"
" ite eq @ explicit IT needed for the 2b label\n"
"2: strexeq %0, %3, [%4]\n"
" movne %0, #0\n"
" teq %0, #0\n"
" bne 1b\n"
__futex_atomic_ex_table("%5")
: "=&r" (ret), "=&r" (val)
: "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
: "cc", "memory");
smp_mb();
*uval = val;
return ret;
}
#else /* !SMP, we can work around lack of atomic ops by disabling preemption */
#include <linux/preempt.h>
#include <asm/domain.h>
#define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
__asm__ __volatile__( \
"1: " TUSER(ldr) " %1, [%3]\n" \
" " insn "\n" \
"2: " TUSER(str) " %0, [%3]\n" \
" mov %0, #0\n" \
__futex_atomic_ex_table("%5") \
: "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \
: "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \
: "cc", "memory")
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
u32 val;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
__asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
"1: " TUSER(ldr) " %1, [%4]\n"
" teq %1, %2\n"
" it eq @ explicit IT needed for the 2b label\n"
"2: " TUSER(streq) " %3, [%4]\n"
__futex_atomic_ex_table("%5")
: "+r" (ret), "=&r" (val)
: "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
: "cc", "memory");
*uval = val;
return ret;
}
#endif /* !SMP */
static inline int
futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
{
int op = (encoded_op >> 28) & 7;
int cmp = (encoded_op >> 24) & 15;
int oparg = (encoded_op << 8) >> 20;
int cmparg = (encoded_op << 20) >> 20;
int oldval = 0, ret, tmp;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
pagefault_disable(); /* implies preempt_disable() */
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
pagefault_enable(); /* subsumes preempt_enable() */
if (!ret) {
switch (cmp) {
case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
default: ret = -ENOSYS;
}
}
return ret;
}
#endif /* __KERNEL__ */
#endif /* _ASM_ARM_FUTEX_H */
|
