Subversion Repositories HelenOS

Rev

Rev 534 | Rev 557 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
1 jermar 1 
/*
2 
 * Copyright (C) 2001-2004 Jakub Jermar
3 
 * All rights reserved.
4 
 *
5 
 * Redistribution and use in source and binary forms, with or without
6 
 * modification, are permitted provided that the following conditions
7 
 * are met:
8 
 *
9 
 * - Redistributions of source code must retain the above copyright
10 
 *   notice, this list of conditions and the following disclaimer.
11 
 * - Redistributions in binary form must reproduce the above copyright
12 
 *   notice, this list of conditions and the following disclaimer in the
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
15 
 *   derived from this software without specific prior written permission.
16 
 *
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
19 
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
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
26 
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 
 */
28 
 
383 jermar 29 
#include <synch/spinlock.h>
111 palkovsky 30 
#include <arch/atomic.h>
153 jermar 31 
#include <arch/barrier.h>
383 jermar 32 
#include <arch.h>
223 jermar 33 
#include <preemption.h>
195 vana 34 
#include <print.h>
383 jermar 35 
#include <debug.h>
552 palkovsky 36 
#include <symtab.h>
1 jermar 37 
 
458 decky 38 
#ifdef CONFIG_SMP
1 jermar 39 
 
383 jermar 40 
/** Initialize spinlock
41 
 *
42 
 * Initialize spinlock.
43 
 *
44 
 * @param sl Pointer to spinlock_t structure.
45 
 */
552 palkovsky 46 
void spinlock_initialize(spinlock_t *sl, char *name)
1 jermar 47 
{
48 
    sl->val = 0;
552 palkovsky 49 
#ifdef CONFIG_DEBUG_SPINLOCK
50 
    sl->name = name;
51 
#endif 
1 jermar 52 
}
53 
 
458 decky 54 
#ifdef CONFIG_DEBUG_SPINLOCK
383 jermar 55 
/** Lock spinlock
56 
 *
57 
 * Lock spinlock.
58 
 * This version has limitted ability to report
59 
 * possible occurence of deadlock.
60 
 *
61 
 * @param sl Pointer to spinlock_t structure.
62 
 */
1 jermar 63 
void spinlock_lock(spinlock_t *sl)
64 
{
65 
    int i = 0;
552 palkovsky 66 
    __address caller = ((__address *) &sl)[-1];
67 
    char *symbol;
1 jermar 68 
 
223 jermar 69 
    preemption_disable();
1 jermar 70 
    while (test_and_set(&sl->val)) {
71 
        if (i++ > 300000) {
552 palkovsky 72 
            printf("cpu%d: looping on spinlock %p:%s, caller=%p",
73 
                   CPU->id, sl, sl->name, caller);
74 
            symbol = get_symtab_entry(caller);
75 
            if (symbol)
76 
                printf("(%s)", symbol);
77 
            printf("\n");
1 jermar 78 
            i = 0;
79 
        }
80 
    }
383 jermar 81 
 
82 
    /*
83 
     * Prevent critical section code from bleeding out this way up.
84 
     */
153 jermar 85 
    CS_ENTER_BARRIER();
1 jermar 86 
 
87 
}
383 jermar 88 
 
1 jermar 89 
#else
383 jermar 90 
 
91 
/** Lock spinlock
92 
 *
93 
 * Lock spinlock.
94 
 *
95 
 * @param sl Pointer to spinlock_t structure.
96 
 */
1 jermar 97 
void spinlock_lock(spinlock_t *sl)
98 
{
223 jermar 99 
    preemption_disable();
100 
 
1 jermar 101 
    /*
102 
     * Each architecture has its own efficient/recommended
103 
     * implementation of spinlock.
104 
     */
105 
    spinlock_arch(&sl->val);
383 jermar 106 
 
107 
    /*
108 
     * Prevent critical section code from bleeding out this way up.
109 
     */
153 jermar 110 
    CS_ENTER_BARRIER();
1 jermar 111 
}
112 
#endif
113 
 
383 jermar 114 
/** Lock spinlock conditionally
115 
 *
116 
 * Lock spinlock conditionally.
117 
 * If the spinlock is not available at the moment,
118 
 * signal failure.
119 
 *
120 
 * @param sl Pointer to spinlock_t structure.
121 
 *
122 
 * @return Zero on failure, non-zero otherwise.
123 
 */
1 jermar 124 
int spinlock_trylock(spinlock_t *sl)
125 
{
153 jermar 126 
    int rc;
127 
 
223 jermar 128 
    preemption_disable();
153 jermar 129 
    rc = !test_and_set(&sl->val);
383 jermar 130 
 
131 
    /*
132 
     * Prevent critical section code from bleeding out this way up.
133 
     */
153 jermar 134 
    CS_ENTER_BARRIER();
223 jermar 135 
 
136 
    if (!rc)
137 
        preemption_enable();
153 jermar 138 
 
139 
    return rc;
1 jermar 140 
}
141 
 
383 jermar 142 
/** Unlock spinlock
143 
 *
144 
 * Unlock spinlock.
145 
 *
146 
 * @param sl Pointer to spinlock_t structure.
147 
 */
1 jermar 148 
void spinlock_unlock(spinlock_t *sl)
149 
{
383 jermar 150 
    ASSERT(sl->val != 0);
151 
 
152 
    /*
153 
     * Prevent critical section code from bleeding out this way down.
154 
     */
153 jermar 155 
    CS_LEAVE_BARRIER();
383 jermar 156 
 
1 jermar 157 
    sl->val = 0;
223 jermar 158 
    preemption_enable();
1 jermar 159 
}
160 
 
161 
#endif