| 1 | /*
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| 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 |
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| 29 | #include <arch.h>
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| 30 |
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| 31 | #include <arch/atomic.h>
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| 32 | #include <arch/barrier.h>
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| 33 | #include <synch/spinlock.h>
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| 34 | #include <preemption.h>
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| 35 | #include <print.h>
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| 36 |
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| 37 | #ifdef __SMP__
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| 38 |
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| 39 | void spinlock_initialize(spinlock_t *sl)
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| 40 | {
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| 41 | sl->val = 0;
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| 42 | }
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| 43 |
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| 44 | #ifdef DEBUG_SPINLOCK
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| 45 | void spinlock_lock(spinlock_t *sl)
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| 46 | {
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| 47 | int i = 0;
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| 48 | __address caller = ((__u32 *) &sl)[-1];
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| 49 |
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| 50 | preemption_disable();
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| 51 | while (test_and_set(&sl->val)) {
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| 52 | if (i++ > 300000) {
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| 53 | printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller);
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| 54 | i = 0;
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| 55 | }
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| 56 | }
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| 57 | CS_ENTER_BARRIER();
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| 58 |
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| 59 | }
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| 60 | #else
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| 61 | void spinlock_lock(spinlock_t *sl)
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| 62 | {
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| 63 | preemption_disable();
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| 64 |
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| 65 | /*
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| 66 | * Each architecture has its own efficient/recommended
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| 67 | * implementation of spinlock.
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| 68 | */
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| 69 | spinlock_arch(&sl->val);
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| 70 | CS_ENTER_BARRIER();
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| 71 | }
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| 72 | #endif
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| 73 |
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| 74 | int spinlock_trylock(spinlock_t *sl)
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| 75 | {
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| 76 | int rc;
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| 77 |
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| 78 | preemption_disable();
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| 79 | rc = !test_and_set(&sl->val);
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| 80 | CS_ENTER_BARRIER();
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| 81 |
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| 82 | if (!rc)
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| 83 | preemption_enable();
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| 84 |
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| 85 | return rc;
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| 86 | }
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| 87 |
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| 88 | void spinlock_unlock(spinlock_t *sl)
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| 89 | {
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| 90 | CS_LEAVE_BARRIER();
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| 91 | sl->val = 0;
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| 92 | preemption_enable();
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| 93 | }
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| 94 |
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| 95 | #endif
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