Subversion Repositories HelenOS

Rev

Rev 2927 | Rev 4346 | Go to most recent revision | Only display areas with differences | Ignore whitespace | Details | Blame | Last modification | View Log | RSS feed

Rev 2927 Rev 3149
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
void spinlock_lock_debug(spinlock_t *sl)
76
void spinlock_lock_debug(spinlock_t *sl)
77
{
77
{
78
    count_t i = 0;
78
    count_t i = 0;
79
    char *symbol;
79
    char *symbol;
80
    bool deadlock_reported = false;
80
    bool deadlock_reported = false;
81
 
81
 
82
    preemption_disable();
82
    preemption_disable();
83
    while (test_and_set(&sl->val)) {
83
    while (test_and_set(&sl->val)) {
84
 
84
 
85
        /*
85
        /*
86
         * We need to be careful about printf_lock and fb_lock.
86
         * We need to be careful about printf_lock and fb_lock.
87
         * Both of them are used to report deadlocks via
87
         * Both of them are used to report deadlocks via
88
         * printf() and fb_putchar().
88
         * printf() and fb_putchar().
89
         *
89
         *
90
         * We trust our code that there is no possible deadlock
90
         * We trust our code that there is no possible deadlock
91
         * caused by these two locks (except when an exception
91
         * caused by these two locks (except when an exception
92
         * is triggered for instance by printf() or fb_putchar()).
92
         * is triggered for instance by printf() or fb_putchar()).
93
         * However, we encountered false positives caused by very
93
         * However, we encountered false positives caused by very
94
         * slow VESA framebuffer interaction (especially when
94
         * slow VESA framebuffer interaction (especially when
95
         * run in a simulator) that caused problems with both
95
         * run in a simulator) that caused problems with both
96
         * printf_lock and fb_lock.
96
         * printf_lock and fb_lock.
97
         *
97
         *
98
         * Possible deadlocks on both printf_lock and fb_lock
98
         * Possible deadlocks on both printf_lock and fb_lock
99
         * are therefore not reported as they would cause an
99
         * are therefore not reported as they would cause an
100
         * infinite recursion.
100
         * infinite recursion.
101
         */
101
         */
102
        if (sl == &printf_lock)
102
        if (sl == &printf_lock)
103
            continue;
103
            continue;
104
#ifdef CONFIG_FB
104
#ifdef CONFIG_FB
105
        if (sl == &fb_lock)
105
        if (sl == &fb_lock)
106
            continue;
106
            continue;
107
#endif
107
#endif
108
        if (i++ > DEADLOCK_THRESHOLD) {
108
        if (i++ > DEADLOCK_THRESHOLD) {
109
            printf("cpu%d: looping on spinlock %.*p:%s, "
109
            printf("cpu%u: looping on spinlock %" PRIp ":%s, caller=%" PRIp,
110
                "caller=%.*p", CPU->id, sizeof(uintptr_t) * 2, sl,
-
 
111
                sl->name, sizeof(uintptr_t) * 2, CALLER);
110
                CPU->id, sl, sl->name, CALLER);
112
            symbol = get_symtab_entry(CALLER);
111
            symbol = get_symtab_entry(CALLER);
113
            if (symbol)
112
            if (symbol)
114
                printf("(%s)", symbol);
113
                printf("(%s)", symbol);
115
            printf("\n");
114
            printf("\n");
116
            i = 0;
115
            i = 0;
117
            deadlock_reported = true;
116
            deadlock_reported = true;
118
        }
117
        }
119
    }
118
    }
120
 
119
 
121
    if (deadlock_reported)
120
    if (deadlock_reported)
122
        printf("cpu%d: not deadlocked\n", CPU->id);
121
        printf("cpu%u: not deadlocked\n", CPU->id);
123
 
122
 
124
    /*
123
    /*
125
     * Prevent critical section code from bleeding out this way up.
124
     * Prevent critical section code from bleeding out this way up.
126
     */
125
     */
127
    CS_ENTER_BARRIER();
126
    CS_ENTER_BARRIER();
128
}
127
}
129
#endif
128
#endif
130
 
129
 
131
/** Lock spinlock conditionally
130
/** Lock spinlock conditionally
132
 *
131
 *
133
 * Lock spinlock conditionally.
132
 * Lock spinlock conditionally.
134
 * If the spinlock is not available at the moment,
133
 * If the spinlock is not available at the moment,
135
 * signal failure.
134
 * signal failure.
136
 *
135
 *
137
 * @param sl Pointer to spinlock_t structure.
136
 * @param sl Pointer to spinlock_t structure.
138
 *
137
 *
139
 * @return Zero on failure, non-zero otherwise.
138
 * @return Zero on failure, non-zero otherwise.
140
 */
139
 */
141
int spinlock_trylock(spinlock_t *sl)
140
int spinlock_trylock(spinlock_t *sl)
142
{
141
{
143
    int rc;
142
    int rc;
144
   
143
   
145
    preemption_disable();
144
    preemption_disable();
146
    rc = !test_and_set(&sl->val);
145
    rc = !test_and_set(&sl->val);
147
 
146
 
148
    /*
147
    /*
149
     * Prevent critical section code from bleeding out this way up.
148
     * Prevent critical section code from bleeding out this way up.
150
     */
149
     */
151
    CS_ENTER_BARRIER();
150
    CS_ENTER_BARRIER();
152
 
151
 
153
    if (!rc)
152
    if (!rc)
154
        preemption_enable();
153
        preemption_enable();
155
   
154
   
156
    return rc;
155
    return rc;
157
}
156
}
158
 
157
 
159
#endif
158
#endif
160
 
159
 
161
/** @}
160
/** @}
162
 */
161
 */
163
 
162