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
167
168
169
170
171
|
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Vineetg: August 2010: From Android kernel work
*/
#ifndef _ASM_FUTEX_H
#define _ASM_FUTEX_H
#include <linux/futex.h>
#include <linux/preempt.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#ifdef CONFIG_ARC_HAS_LLSC
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
\
smp_mb(); \
__asm__ __volatile__( \
"1: llock %1, [%2] \n" \
insn "\n" \
"2: scond %0, [%2] \n" \
" bnz 1b \n" \
" mov %0, 0 \n" \
"3: \n" \
" .section .fixup,\"ax\" \n" \
" .align 4 \n" \
"4: mov %0, %4 \n" \
" j 3b \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" .align 4 \n" \
" .word 1b, 4b \n" \
" .word 2b, 4b \n" \
" .previous \n" \
\
: "=&r" (ret), "=&r" (oldval) \
: "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
: "cc", "memory"); \
smp_mb() \
#else /* !CONFIG_ARC_HAS_LLSC */
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
\
smp_mb(); \
__asm__ __volatile__( \
"1: ld %1, [%2] \n" \
insn "\n" \
"2: st %0, [%2] \n" \
" mov %0, 0 \n" \
"3: \n" \
" .section .fixup,\"ax\" \n" \
" .align 4 \n" \
"4: mov %0, %4 \n" \
" j 3b \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" .align 4 \n" \
" .word 1b, 4b \n" \
" .word 2b, 4b \n" \
" .previous \n" \
\
: "=&r" (ret), "=&r" (oldval) \
: "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
: "cc", "memory"); \
smp_mb() \
#endif
static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
u32 __user *uaddr)
{
int oldval = 0, ret;
#ifndef CONFIG_ARC_HAS_LLSC
preempt_disable(); /* to guarantee atomic r-m-w of futex op */
#endif
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
/* oldval = *uaddr; *uaddr += oparg ; ret = *uaddr */
__futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
pagefault_enable();
#ifndef CONFIG_ARC_HAS_LLSC
preempt_enable();
#endif
if (!ret)
*oval = oldval;
return ret;
}
/*
* cmpxchg of futex (pagefaults disabled by caller)
* Return 0 for success, -EFAULT otherwise
*/
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 expval,
u32 newval)
{
int ret = 0;
u32 existval;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
#ifndef CONFIG_ARC_HAS_LLSC
preempt_disable(); /* to guarantee atomic r-m-w of futex op */
#endif
smp_mb();
__asm__ __volatile__(
#ifdef CONFIG_ARC_HAS_LLSC
"1: llock %1, [%4] \n"
" brne %1, %2, 3f \n"
"2: scond %3, [%4] \n"
" bnz 1b \n"
#else
"1: ld %1, [%4] \n"
" brne %1, %2, 3f \n"
"2: st %3, [%4] \n"
#endif
"3: \n"
" .section .fixup,\"ax\" \n"
"4: mov %0, %5 \n"
" j 3b \n"
" .previous \n"
" .section __ex_table,\"a\" \n"
" .align 4 \n"
" .word 1b, 4b \n"
" .word 2b, 4b \n"
" .previous\n"
: "+&r"(ret), "=&r"(existval)
: "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT)
: "cc", "memory");
smp_mb();
#ifndef CONFIG_ARC_HAS_LLSC
preempt_enable();
#endif
*uval = existval;
return ret;
}
#endif
|
