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1 | /* |
1 | /* |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | #include <synch/spinlock.h> |
29 | #include <synch/spinlock.h> |
30 | #include <arch/atomic.h> |
30 | #include <arch/atomic.h> |
31 | #include <arch/barrier.h> |
31 | #include <arch/barrier.h> |
32 | #include <arch.h> |
32 | #include <arch.h> |
33 | #include <preemption.h> |
33 | #include <preemption.h> |
34 | #include <print.h> |
34 | #include <print.h> |
35 | #include <debug.h> |
35 | #include <debug.h> |
36 | 36 | ||
37 | #ifdef CONFIG_SMP |
37 | #ifdef CONFIG_SMP |
38 | 38 | ||
39 | /** Initialize spinlock |
39 | /** Initialize spinlock |
40 | * |
40 | * |
41 | * Initialize spinlock. |
41 | * Initialize spinlock. |
42 | * |
42 | * |
43 | * @param sl Pointer to spinlock_t structure. |
43 | * @param sl Pointer to spinlock_t structure. |
44 | */ |
44 | */ |
45 | void spinlock_initialize(spinlock_t *sl) |
45 | void spinlock_initialize(spinlock_t *sl) |
46 | { |
46 | { |
47 | sl->val = 0; |
47 | sl->val = 0; |
48 | } |
48 | } |
49 | 49 | ||
50 | #ifdef CONFIG_DEBUG_SPINLOCK |
50 | #ifdef CONFIG_DEBUG_SPINLOCK |
51 | /** Lock spinlock |
51 | /** Lock spinlock |
52 | * |
52 | * |
53 | * Lock spinlock. |
53 | * Lock spinlock. |
54 | * This version has limitted ability to report |
54 | * This version has limitted ability to report |
55 | * possible occurence of deadlock. |
55 | * possible occurence of deadlock. |
56 | * |
56 | * |
57 | * @param sl Pointer to spinlock_t structure. |
57 | * @param sl Pointer to spinlock_t structure. |
58 | */ |
58 | */ |
59 | void spinlock_lock(spinlock_t *sl) |
59 | void spinlock_lock(spinlock_t *sl) |
60 | { |
60 | { |
61 | int i = 0; |
61 | int i = 0; |
62 | __address caller = ((__u32 *) &sl)[-1]; |
62 | __address caller = ((__u32 *) &sl)[-1]; |
63 | 63 | ||
64 | preemption_disable(); |
64 | preemption_disable(); |
65 | while (test_and_set(&sl->val)) { |
65 | while (test_and_set(&sl->val)) { |
66 | if (i++ > 300000) { |
66 | if (i++ > 300000) { |
67 | printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller); |
67 | printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller); |
68 | i = 0; |
68 | i = 0; |
69 | } |
69 | } |
70 | } |
70 | } |
71 | 71 | ||
72 | /* |
72 | /* |
73 | * Prevent critical section code from bleeding out this way up. |
73 | * Prevent critical section code from bleeding out this way up. |
74 | */ |
74 | */ |
75 | CS_ENTER_BARRIER(); |
75 | CS_ENTER_BARRIER(); |
76 | 76 | ||
77 | } |
77 | } |
78 | 78 | ||
79 | #else |
79 | #else |
80 | 80 | ||
81 | /** Lock spinlock |
81 | /** Lock spinlock |
82 | * |
82 | * |
83 | * Lock spinlock. |
83 | * Lock spinlock. |
84 | * |
84 | * |
85 | * @param sl Pointer to spinlock_t structure. |
85 | * @param sl Pointer to spinlock_t structure. |
86 | */ |
86 | */ |
87 | void spinlock_lock(spinlock_t *sl) |
87 | void spinlock_lock(spinlock_t *sl) |
88 | { |
88 | { |
89 | preemption_disable(); |
89 | preemption_disable(); |
90 | 90 | ||
91 | /* |
91 | /* |
92 | * Each architecture has its own efficient/recommended |
92 | * Each architecture has its own efficient/recommended |
93 | * implementation of spinlock. |
93 | * implementation of spinlock. |
94 | */ |
94 | */ |
95 | spinlock_arch(&sl->val); |
95 | spinlock_arch(&sl->val); |
96 | 96 | ||
97 | /* |
97 | /* |
98 | * Prevent critical section code from bleeding out this way up. |
98 | * Prevent critical section code from bleeding out this way up. |
99 | */ |
99 | */ |
100 | CS_ENTER_BARRIER(); |
100 | CS_ENTER_BARRIER(); |
101 | } |
101 | } |
102 | #endif |
102 | #endif |
103 | 103 | ||
104 | /** Lock spinlock conditionally |
104 | /** Lock spinlock conditionally |
105 | * |
105 | * |
106 | * Lock spinlock conditionally. |
106 | * Lock spinlock conditionally. |
107 | * If the spinlock is not available at the moment, |
107 | * If the spinlock is not available at the moment, |
108 | * signal failure. |
108 | * signal failure. |
109 | * |
109 | * |
110 | * @param sl Pointer to spinlock_t structure. |
110 | * @param sl Pointer to spinlock_t structure. |
111 | * |
111 | * |
112 | * @return Zero on failure, non-zero otherwise. |
112 | * @return Zero on failure, non-zero otherwise. |
113 | */ |
113 | */ |
114 | int spinlock_trylock(spinlock_t *sl) |
114 | int spinlock_trylock(spinlock_t *sl) |
115 | { |
115 | { |
116 | int rc; |
116 | int rc; |
117 | 117 | ||
118 | preemption_disable(); |
118 | preemption_disable(); |
119 | rc = !test_and_set(&sl->val); |
119 | rc = !test_and_set(&sl->val); |
120 | 120 | ||
121 | /* |
121 | /* |
122 | * Prevent critical section code from bleeding out this way up. |
122 | * Prevent critical section code from bleeding out this way up. |
123 | */ |
123 | */ |
124 | CS_ENTER_BARRIER(); |
124 | CS_ENTER_BARRIER(); |
125 | 125 | ||
126 | if (!rc) |
126 | if (!rc) |
127 | preemption_enable(); |
127 | preemption_enable(); |
128 | 128 | ||
129 | return rc; |
129 | return rc; |
130 | } |
130 | } |
131 | 131 | ||
132 | /** Unlock spinlock |
132 | /** Unlock spinlock |
133 | * |
133 | * |
134 | * Unlock spinlock. |
134 | * Unlock spinlock. |
135 | * |
135 | * |
136 | * @param sl Pointer to spinlock_t structure. |
136 | * @param sl Pointer to spinlock_t structure. |
137 | */ |
137 | */ |
138 | void spinlock_unlock(spinlock_t *sl) |
138 | void spinlock_unlock(spinlock_t *sl) |
139 | { |
139 | { |
140 | ASSERT(sl->val != 0); |
140 | ASSERT(sl->val != 0); |
141 | 141 | ||
142 | /* |
142 | /* |
143 | * Prevent critical section code from bleeding out this way down. |
143 | * Prevent critical section code from bleeding out this way down. |
144 | */ |
144 | */ |
145 | CS_LEAVE_BARRIER(); |
145 | CS_LEAVE_BARRIER(); |
146 | 146 | ||
147 | sl->val = 0; |
147 | sl->val = 0; |
148 | preemption_enable(); |
148 | preemption_enable(); |
149 | } |
149 | } |
150 | 150 | ||
151 | #endif |
151 | #endif |
152 | 152 |