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| 1 | jermar | 1 | /* |
| 2 | * Copyright (C) 2001-2004 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 1264 | jermar | 29 | /** |
| 30 | * @file spinlock.c |
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| 31 | * @brief Spinlocks. |
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| 32 | */ |
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| 33 | |||
| 383 | jermar | 34 | #include <synch/spinlock.h> |
| 1104 | jermar | 35 | #include <atomic.h> |
| 153 | jermar | 36 | #include <arch/barrier.h> |
| 383 | jermar | 37 | #include <arch.h> |
| 223 | jermar | 38 | #include <preemption.h> |
| 195 | vana | 39 | #include <print.h> |
| 383 | jermar | 40 | #include <debug.h> |
| 552 | palkovsky | 41 | #include <symtab.h> |
| 1 | jermar | 42 | |
| 458 | decky | 43 | #ifdef CONFIG_SMP |
| 1 | jermar | 44 | |
| 383 | jermar | 45 | /** Initialize spinlock |
| 46 | * |
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| 47 | * Initialize spinlock. |
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| 48 | * |
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| 49 | * @param sl Pointer to spinlock_t structure. |
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| 50 | */ |
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| 552 | palkovsky | 51 | void spinlock_initialize(spinlock_t *sl, char *name) |
| 1 | jermar | 52 | { |
| 625 | palkovsky | 53 | atomic_set(&sl->val, 0); |
| 552 | palkovsky | 54 | #ifdef CONFIG_DEBUG_SPINLOCK |
| 55 | sl->name = name; |
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| 56 | #endif |
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| 1 | jermar | 57 | } |
| 58 | |||
| 383 | jermar | 59 | /** Lock spinlock |
| 60 | * |
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| 61 | * Lock spinlock. |
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| 62 | * This version has limitted ability to report |
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| 63 | * possible occurence of deadlock. |
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| 64 | * |
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| 65 | * @param sl Pointer to spinlock_t structure. |
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| 66 | */ |
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| 1100 | palkovsky | 67 | #ifdef CONFIG_DEBUG_SPINLOCK |
| 68 | void spinlock_lock_debug(spinlock_t *sl) |
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| 1 | jermar | 69 | { |
| 557 | jermar | 70 | count_t i = 0; |
| 552 | palkovsky | 71 | char *symbol; |
| 557 | jermar | 72 | bool deadlock_reported = false; |
| 1 | jermar | 73 | |
| 223 | jermar | 74 | preemption_disable(); |
| 1 | jermar | 75 | while (test_and_set(&sl->val)) { |
| 787 | palkovsky | 76 | if (i++ > 300000 && sl!=&printflock) { |
| 1224 | cejka | 77 | printf("cpu%d: looping on spinlock %.*p:%s, caller=%.*p", |
| 78 | CPU->id, sizeof(__address) * 2, sl, sl->name, sizeof(__address) * 2, CALLER); |
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| 622 | palkovsky | 79 | symbol = get_symtab_entry(CALLER); |
| 552 | palkovsky | 80 | if (symbol) |
| 81 | printf("(%s)", symbol); |
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| 82 | printf("\n"); |
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| 1 | jermar | 83 | i = 0; |
| 557 | jermar | 84 | deadlock_reported = true; |
| 1 | jermar | 85 | } |
| 86 | } |
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| 383 | jermar | 87 | |
| 557 | jermar | 88 | if (deadlock_reported) |
| 89 | printf("cpu%d: not deadlocked\n", CPU->id); |
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| 90 | |||
| 383 | jermar | 91 | /* |
| 92 | * Prevent critical section code from bleeding out this way up. |
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| 93 | */ |
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| 153 | jermar | 94 | CS_ENTER_BARRIER(); |
| 1 | jermar | 95 | } |
| 96 | #endif |
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| 97 | |||
| 383 | jermar | 98 | /** Lock spinlock conditionally |
| 99 | * |
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| 100 | * Lock spinlock conditionally. |
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| 101 | * If the spinlock is not available at the moment, |
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| 102 | * signal failure. |
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| 103 | * |
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| 104 | * @param sl Pointer to spinlock_t structure. |
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| 105 | * |
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| 106 | * @return Zero on failure, non-zero otherwise. |
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| 107 | */ |
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| 1 | jermar | 108 | int spinlock_trylock(spinlock_t *sl) |
| 109 | { |
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| 153 | jermar | 110 | int rc; |
| 111 | |||
| 223 | jermar | 112 | preemption_disable(); |
| 153 | jermar | 113 | rc = !test_and_set(&sl->val); |
| 383 | jermar | 114 | |
| 115 | /* |
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| 116 | * Prevent critical section code from bleeding out this way up. |
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| 117 | */ |
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| 153 | jermar | 118 | CS_ENTER_BARRIER(); |
| 223 | jermar | 119 | |
| 120 | if (!rc) |
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| 121 | preemption_enable(); |
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| 153 | jermar | 122 | |
| 123 | return rc; |
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| 1 | jermar | 124 | } |
| 125 | |||
| 126 | #endif |