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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 | /** @addtogroup sync |
29 | /** @addtogroup sync |
30 | * @{ |
30 | * @{ |
31 | */ |
31 | */ |
32 | 32 | ||
33 | /** |
33 | /** |
34 | * @file |
34 | * @file |
35 | * @brief Spinlocks. |
35 | * @brief Spinlocks. |
36 | */ |
36 | */ |
37 | 37 | ||
38 | #include <synch/spinlock.h> |
38 | #include <synch/spinlock.h> |
39 | #include <atomic.h> |
39 | #include <atomic.h> |
40 | #include <arch/barrier.h> |
40 | #include <arch/barrier.h> |
41 | #include <arch.h> |
41 | #include <arch.h> |
42 | #include <preemption.h> |
42 | #include <preemption.h> |
43 | #include <print.h> |
43 | #include <print.h> |
44 | #include <debug.h> |
44 | #include <debug.h> |
45 | #include <symtab.h> |
45 | #include <symtab.h> |
46 | 46 | ||
47 | #ifdef CONFIG_FB |
47 | #ifdef CONFIG_FB |
48 | #include <genarch/fb/fb.h> |
48 | #include <genarch/fb/fb.h> |
49 | #endif |
49 | #endif |
50 | 50 | ||
51 | #ifdef CONFIG_SMP |
51 | #ifdef CONFIG_SMP |
52 | 52 | ||
53 | /** Initialize spinlock |
53 | /** Initialize spinlock |
54 | * |
54 | * |
55 | * Initialize spinlock. |
55 | * Initialize spinlock. |
56 | * |
56 | * |
57 | * @param sl Pointer to spinlock_t structure. |
57 | * @param sl Pointer to spinlock_t structure. |
58 | */ |
58 | */ |
59 | void spinlock_initialize(spinlock_t *sl, char *name) |
59 | void spinlock_initialize(spinlock_t *sl, char *name) |
60 | { |
60 | { |
61 | atomic_set(&sl->val, 0); |
61 | atomic_set(&sl->val, 0); |
62 | #ifdef CONFIG_DEBUG_SPINLOCK |
62 | #ifdef CONFIG_DEBUG_SPINLOCK |
63 | sl->name = name; |
63 | sl->name = name; |
64 | #endif |
64 | #endif |
65 | } |
65 | } |
66 | 66 | ||
67 | /** Lock spinlock |
67 | /** Lock spinlock |
68 | * |
68 | * |
69 | * Lock spinlock. |
69 | * Lock spinlock. |
70 | * This version has limitted ability to report |
70 | * This version has limitted ability to report |
71 | * possible occurence of deadlock. |
71 | * possible occurence of deadlock. |
72 | * |
72 | * |
73 | * @param sl Pointer to spinlock_t structure. |
73 | * @param sl Pointer to spinlock_t structure. |
74 | */ |
74 | */ |
75 | #ifdef CONFIG_DEBUG_SPINLOCK |
75 | #ifdef CONFIG_DEBUG_SPINLOCK |
76 | #define DEADLOCK_THRESHOLD 100000000 |
76 | #define DEADLOCK_THRESHOLD 100000000 |
77 | void spinlock_lock_debug(spinlock_t *sl) |
77 | void spinlock_lock_debug(spinlock_t *sl) |
78 | { |
78 | { |
79 | count_t i = 0; |
79 | count_t i = 0; |
80 | char *symbol; |
80 | char *symbol; |
81 | bool deadlock_reported = false; |
81 | bool deadlock_reported = false; |
82 | 82 | ||
83 | preemption_disable(); |
83 | preemption_disable(); |
84 | while (test_and_set(&sl->val)) { |
84 | while (test_and_set(&sl->val)) { |
85 | 85 | ||
86 | /* |
86 | /* |
87 | * We need to be careful about printflock and fb_lock. |
87 | * We need to be careful about printflock and fb_lock. |
88 | * Both of them are used to report deadlocks via |
88 | * Both of them are used to report deadlocks via |
89 | * printf() and fb_putchar(). |
89 | * printf() and fb_putchar(). |
90 | * |
90 | * |
91 | * We trust our code that there is no possible deadlock |
91 | * We trust our code that there is no possible deadlock |
92 | * caused by these two locks (except when an exception |
92 | * caused by these two locks (except when an exception |
93 | * is triggered for instance by printf() or fb_putchar()). |
93 | * is triggered for instance by printf() or fb_putchar()). |
94 | * However, we encountered false positives caused by very |
94 | * However, we encountered false positives caused by very |
95 | * slow VESA framebuffer interaction (especially when |
95 | * slow VESA framebuffer interaction (especially when |
96 | * run in a simulator) that caused problems with both |
96 | * run in a simulator) that caused problems with both |
97 | * printflock and fb_lock. |
97 | * printflock and fb_lock. |
98 | * |
98 | * |
99 | * Possible deadlocks on both printflock and fb_lock |
99 | * Possible deadlocks on both printflock and fb_lock |
100 | * are therefore not reported as they would cause an |
100 | * are therefore not reported as they would cause an |
101 | * infinite recursion. |
101 | * infinite recursion. |
102 | */ |
102 | */ |
103 | if (sl == &printflock) |
103 | if (sl == &printflock) |
104 | continue; |
104 | continue; |
105 | #ifdef CONFIG_FB |
105 | #ifdef CONFIG_FB |
106 | if (sl == &fb_lock) |
106 | if (sl == &fb_lock) |
107 | continue; |
107 | continue; |
108 | #endif |
108 | #endif |
109 | if (i++ > DEADLOCK_THRESHOLD) { |
109 | if (i++ > DEADLOCK_THRESHOLD) { |
110 | printf("cpu%d: looping on spinlock %.*p:%s, caller=%.*p", |
110 | printf("cpu%d: looping on spinlock %.*p:%s, caller=%.*p", |
111 | CPU->id, sizeof(__address) * 2, sl, sl->name, sizeof(__address) * 2, CALLER); |
111 | CPU->id, sizeof(__address) * 2, sl, sl->name, sizeof(__address) * 2, CALLER); |
112 | symbol = get_symtab_entry(CALLER); |
112 | symbol = get_symtab_entry(CALLER); |
113 | if (symbol) |
113 | if (symbol) |
114 | printf("(%s)", symbol); |
114 | printf("(%s)", symbol); |
115 | printf("\n"); |
115 | printf("\n"); |
116 | i = 0; |
116 | i = 0; |
117 | deadlock_reported = true; |
117 | deadlock_reported = true; |
118 | } |
118 | } |
119 | } |
119 | } |
120 | 120 | ||
121 | if (deadlock_reported) |
121 | if (deadlock_reported) |
122 | printf("cpu%d: not deadlocked\n", CPU->id); |
122 | printf("cpu%d: not deadlocked\n", CPU->id); |
123 | 123 | ||
124 | /* |
124 | /* |
125 | * Prevent critical section code from bleeding out this way up. |
125 | * Prevent critical section code from bleeding out this way up. |
126 | */ |
126 | */ |
127 | CS_ENTER_BARRIER(); |
127 | CS_ENTER_BARRIER(); |
128 | } |
128 | } |
129 | #endif |
129 | #endif |
130 | 130 | ||
131 | /** Lock spinlock conditionally |
131 | /** Lock spinlock conditionally |
132 | * |
132 | * |
133 | * Lock spinlock conditionally. |
133 | * Lock spinlock conditionally. |
134 | * If the spinlock is not available at the moment, |
134 | * If the spinlock is not available at the moment, |
135 | * signal failure. |
135 | * signal failure. |
136 | * |
136 | * |
137 | * @param sl Pointer to spinlock_t structure. |
137 | * @param sl Pointer to spinlock_t structure. |
138 | * |
138 | * |
139 | * @return Zero on failure, non-zero otherwise. |
139 | * @return Zero on failure, non-zero otherwise. |
140 | */ |
140 | */ |
141 | int spinlock_trylock(spinlock_t *sl) |
141 | int spinlock_trylock(spinlock_t *sl) |
142 | { |
142 | { |
143 | int rc; |
143 | int rc; |
144 | 144 | ||
145 | preemption_disable(); |
145 | preemption_disable(); |
146 | rc = !test_and_set(&sl->val); |
146 | rc = !test_and_set(&sl->val); |
147 | 147 | ||
148 | /* |
148 | /* |
149 | * Prevent critical section code from bleeding out this way up. |
149 | * Prevent critical section code from bleeding out this way up. |
150 | */ |
150 | */ |
151 | CS_ENTER_BARRIER(); |
151 | CS_ENTER_BARRIER(); |
152 | 152 | ||
153 | if (!rc) |
153 | if (!rc) |
154 | preemption_enable(); |
154 | preemption_enable(); |
155 | 155 | ||
156 | return rc; |
156 | return rc; |
157 | } |
157 | } |
158 | 158 | ||
159 | #endif |
159 | #endif |
160 | 160 | ||
161 | /** @} |
161 | /** @} |
162 | */ |
162 | */ |
163 | - | ||
164 | 163 |