WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/synch/spinlock.c


/*
 * Copyright (C) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <synch/spinlock.h>
#include <atomic.h>
#include <arch/barrier.h>
#include <arch.h>
#include <preemption.h>
#include <print.h>
#include <debug.h>
#include <symtab.h>
 
#ifdef CONFIG_SMP
 
/** Initialize spinlock
 *
 * Initialize spinlock.
 *
 * @param sl Pointer to spinlock_t structure.
 */
void spinlock_initialize(spinlock_t *sl, char *name)
{
    atomic_set(&sl->val, 0);
#ifdef CONFIG_DEBUG_SPINLOCK
    sl->name = name;
#endif  
}
 
/** Lock spinlock
 *
 * Lock spinlock.
 * This version has limitted ability to report
 * possible occurence of deadlock.
 *
 * @param sl Pointer to spinlock_t structure.
 */
#ifdef CONFIG_DEBUG_SPINLOCK
void spinlock_lock_debug(spinlock_t *sl)
{
    count_t i = 0;
    char *symbol;
    bool deadlock_reported = false;
 
    preemption_disable();
    while (test_and_set(&sl->val)) {
        if (i++ > 300000 && sl!=&printflock) {
            printf("cpu%d: looping on spinlock %p:%s, caller=%p",
                   CPU->id, sl, sl->name, CALLER);
            symbol = get_symtab_entry(CALLER);
            if (symbol)
                printf("(%s)", symbol);
            printf("\n");
            i = 0;
            deadlock_reported = true;
        }
    }
 
    if (deadlock_reported)
        printf("cpu%d: not deadlocked\n", CPU->id);
 
    /*
     * Prevent critical section code from bleeding out this way up.
     */
    CS_ENTER_BARRIER();
}
#endif
 
/** Lock spinlock conditionally
 *
 * Lock spinlock conditionally.
 * If the spinlock is not available at the moment,
 * signal failure.
 *
 * @param sl Pointer to spinlock_t structure.
 *
 * @return Zero on failure, non-zero otherwise.
 */
int spinlock_trylock(spinlock_t *sl)
{
    int rc;
   
    preemption_disable();
    rc = !test_and_set(&sl->val);
 
    /*
     * Prevent critical section code from bleeding out this way up.
     */
    CS_ENTER_BARRIER();
 
    if (!rc)
        preemption_enable();
   
    return rc;
}
 
#endif
 

Rev 1100	Rev 1104
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 <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	#include <symtab.h>	36	#include <symtab.h>
37		37
38	#ifdef CONFIG_SMP	38	#ifdef CONFIG_SMP
39		39
40	/** Initialize spinlock	40	/** Initialize spinlock
41	*	41	*
42	* Initialize spinlock.	42	* Initialize spinlock.
43	*	43	*
44	* @param sl Pointer to spinlock_t structure.	44	* @param sl Pointer to spinlock_t structure.
45	*/	45	*/
46	void spinlock_initialize(spinlock_t sl, char name)	46	void spinlock_initialize(spinlock_t sl, char name)
47	{	47	{
48	atomic_set(&sl->val, 0);	48	atomic_set(&sl->val, 0);
49	#ifdef CONFIG_DEBUG_SPINLOCK	49	#ifdef CONFIG_DEBUG_SPINLOCK
50	sl->name = name;	50	sl->name = name;
51	#endif	51	#endif
52	}	52	}
53		53
54	/** Lock spinlock	54	/** Lock spinlock
55	*	55	*
56	* Lock spinlock.	56	* Lock spinlock.
57	* This version has limitted ability to report	57	* This version has limitted ability to report
58	* possible occurence of deadlock.	58	* possible occurence of deadlock.
59	*	59	*
60	* @param sl Pointer to spinlock_t structure.	60	* @param sl Pointer to spinlock_t structure.
61	*/	61	*/
62	#ifdef CONFIG_DEBUG_SPINLOCK	62	#ifdef CONFIG_DEBUG_SPINLOCK
63	void spinlock_lock_debug(spinlock_t *sl)	63	void spinlock_lock_debug(spinlock_t *sl)
64	{	64	{
65	count_t i = 0;	65	count_t i = 0;
66	char *symbol;	66	char *symbol;
67	bool deadlock_reported = false;	67	bool deadlock_reported = false;
68		68
69	preemption_disable();	69	preemption_disable();
70	while (test_and_set(&sl->val)) {	70	while (test_and_set(&sl->val)) {
71	if (i++ > 300000 && sl!=&printflock) {	71	if (i++ > 300000 && sl!=&printflock) {
72	printf("cpu%d: looping on spinlock %p:%s, caller=%p",	72	printf("cpu%d: looping on spinlock %p:%s, caller=%p",
73	CPU->id, sl, sl->name, CALLER);	73	CPU->id, sl, sl->name, CALLER);
74	symbol = get_symtab_entry(CALLER);	74	symbol = get_symtab_entry(CALLER);
75	if (symbol)	75	if (symbol)
76	printf("(%s)", symbol);	76	printf("(%s)", symbol);
77	printf("\n");	77	printf("\n");
78	i = 0;	78	i = 0;
79	deadlock_reported = true;	79	deadlock_reported = true;
80	}	80	}
81	}	81	}
82		82
83	if (deadlock_reported)	83	if (deadlock_reported)
84	printf("cpu%d: not deadlocked\n", CPU->id);	84	printf("cpu%d: not deadlocked\n", CPU->id);
85		85
86	/*	86	/*
87	* Prevent critical section code from bleeding out this way up.	87	* Prevent critical section code from bleeding out this way up.
88	*/	88	*/
89	CS_ENTER_BARRIER();	89	CS_ENTER_BARRIER();
90	}	90	}
91	#endif	91	#endif
92		92
93	/** Lock spinlock conditionally	93	/** Lock spinlock conditionally
94	*	94	*
95	* Lock spinlock conditionally.	95	* Lock spinlock conditionally.
96	* If the spinlock is not available at the moment,	96	* If the spinlock is not available at the moment,
97	* signal failure.	97	* signal failure.
98	*	98	*
99	* @param sl Pointer to spinlock_t structure.	99	* @param sl Pointer to spinlock_t structure.
100	*	100	*
101	* @return Zero on failure, non-zero otherwise.	101	* @return Zero on failure, non-zero otherwise.
102	*/	102	*/
103	int spinlock_trylock(spinlock_t *sl)	103	int spinlock_trylock(spinlock_t *sl)
104	{	104	{
105	int rc;	105	int rc;
106		106
107	preemption_disable();	107	preemption_disable();
108	rc = !test_and_set(&sl->val);	108	rc = !test_and_set(&sl->val);
109		109
110	/*	110	/*
111	* Prevent critical section code from bleeding out this way up.	111	* Prevent critical section code from bleeding out this way up.
112	*/	112	*/
113	CS_ENTER_BARRIER();	113	CS_ENTER_BARRIER();
114		114
115	if (!rc)	115	if (!rc)
116	preemption_enable();	116	preemption_enable();
117		117
118	return rc;	118	return rc;
119	}	119	}
120		120
121	#endif	121	#endif
122		122

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/synch/spinlock.c – Rev 1100 → 1104