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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 | |||
29 | #include <arch.h> |
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30 | |||
111 | palkovsky | 31 | #include <arch/atomic.h> |
153 | jermar | 32 | #include <arch/barrier.h> |
1 | jermar | 33 | #include <synch/spinlock.h> |
223 | jermar | 34 | #include <preemption.h> |
195 | vana | 35 | #include <print.h> |
1 | jermar | 36 | |
37 | #ifdef __SMP__ |
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38 | |||
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 | |||
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 | |||
223 | jermar | 50 | preemption_disable(); |
1 | jermar | 51 | while (test_and_set(&sl->val)) { |
52 | if (i++ > 300000) { |
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15 | jermar | 53 | printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller); |
1 | jermar | 54 | i = 0; |
55 | } |
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56 | } |
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153 | jermar | 57 | CS_ENTER_BARRIER(); |
1 | jermar | 58 | |
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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223 | jermar | 63 | preemption_disable(); |
64 | |||
1 | jermar | 65 | /* |
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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153 | jermar | 70 | CS_ENTER_BARRIER(); |
1 | jermar | 71 | } |
72 | #endif |
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73 | |||
74 | int spinlock_trylock(spinlock_t *sl) |
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75 | { |
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153 | jermar | 76 | int rc; |
77 | |||
223 | jermar | 78 | preemption_disable(); |
153 | jermar | 79 | rc = !test_and_set(&sl->val); |
80 | CS_ENTER_BARRIER(); |
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223 | jermar | 81 | |
82 | if (!rc) |
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83 | preemption_enable(); |
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153 | jermar | 84 | |
85 | return rc; |
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1 | jermar | 86 | } |
87 | |||
88 | void spinlock_unlock(spinlock_t *sl) |
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89 | { |
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153 | jermar | 90 | CS_LEAVE_BARRIER(); |
1 | jermar | 91 | sl->val = 0; |
223 | jermar | 92 | preemption_enable(); |
1 | jermar | 93 | } |
94 | |||
95 | #endif |