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
|
/*
* Atomic operations for the Hexagon architecture
*
* Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H
#include <linux/types.h>
#include <asm/cmpxchg.h>
#define ATOMIC_INIT(i) { (i) }
#define atomic_set(v, i) ((v)->counter = (i))
/**
* atomic_read - reads a word, atomically
* @v: pointer to atomic value
*
* Assumes all word reads on our architecture are atomic.
*/
#define atomic_read(v) ((v)->counter)
/**
* atomic_xchg - atomic
* @v: pointer to memory to change
* @new: new value (technically passed in a register -- see xchg)
*/
#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
/**
* atomic_cmpxchg - atomic compare-and-exchange values
* @v: pointer to value to change
* @old: desired old value to match
* @new: new value to put in
*
* Parameters are then pointer, value-in-register, value-in-register,
* and the output is the old value.
*
* Apparently this is complicated for archs that don't support
* the memw_locked like we do (or it's broken or whatever).
*
* Kind of the lynchpin of the rest of the generically defined routines.
* Remember V2 had that bug with dotnew predicate set by memw_locked.
*
* "old" is "expected" old val, __oldval is actual old value
*/
static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
int __oldval;
asm volatile(
"1: %0 = memw_locked(%1);\n"
" { P0 = cmp.eq(%0,%2);\n"
" if (!P0.new) jump:nt 2f; }\n"
" memw_locked(%1,P0) = %3;\n"
" if (!P0) jump 1b;\n"
"2:\n"
: "=&r" (__oldval)
: "r" (&v->counter), "r" (old), "r" (new)
: "memory", "p0"
);
return __oldval;
}
static inline int atomic_add_return(int i, atomic_t *v)
{
int output;
__asm__ __volatile__ (
"1: %0 = memw_locked(%1);\n"
" %0 = add(%0,%2);\n"
" memw_locked(%1,P3)=%0;\n"
" if !P3 jump 1b;\n"
: "=&r" (output)
: "r" (&v->counter), "r" (i)
: "memory", "p3"
);
return output;
}
#define atomic_add(i, v) atomic_add_return(i, (v))
static inline int atomic_sub_return(int i, atomic_t *v)
{
int output;
__asm__ __volatile__ (
"1: %0 = memw_locked(%1);\n"
" %0 = sub(%0,%2);\n"
" memw_locked(%1,P3)=%0\n"
" if !P3 jump 1b;\n"
: "=&r" (output)
: "r" (&v->counter), "r" (i)
: "memory", "p3"
);
return output;
}
#define atomic_sub(i, v) atomic_sub_return(i, (v))
/**
* __atomic_add_unless - add unless the number is a given value
* @v: pointer to value
* @a: amount to add
* @u: unless value is equal to u
*
* Returns old value.
*
*/
static inline int __atomic_add_unless(atomic_t *v, int a, int u)
{
int __oldval;
register int tmp;
asm volatile(
"1: %0 = memw_locked(%2);"
" {"
" p3 = cmp.eq(%0, %4);"
" if (p3.new) jump:nt 2f;"
" %1 = add(%0, %3);"
" }"
" memw_locked(%2, p3) = %1;"
" {"
" if !p3 jump 1b;"
" }"
"2:"
: "=&r" (__oldval), "=&r" (tmp)
: "r" (v), "r" (a), "r" (u)
: "memory", "p3"
);
return __oldval;
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
#define atomic_inc(v) atomic_add(1, (v))
#define atomic_dec(v) atomic_sub(1, (v))
#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
#define atomic_sub_and_test(i, v) (atomic_sub_return(i, (v)) == 0)
#define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
#define atomic_inc_return(v) (atomic_add_return(1, v))
#define atomic_dec_return(v) (atomic_sub_return(1, v))
#endif
|
