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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 | |||
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> |
1 | jermar | 36 | |
458 | decky | 37 | #ifdef CONFIG_SMP |
1 | jermar | 38 | |
383 | jermar | 39 | /** Initialize spinlock |
40 | * |
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41 | * Initialize spinlock. |
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42 | * |
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43 | * @param sl Pointer to spinlock_t structure. |
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44 | */ |
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1 | jermar | 45 | void spinlock_initialize(spinlock_t *sl) |
46 | { |
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47 | sl->val = 0; |
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48 | } |
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49 | |||
458 | decky | 50 | #ifdef CONFIG_DEBUG_SPINLOCK |
383 | jermar | 51 | /** Lock spinlock |
52 | * |
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53 | * Lock spinlock. |
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54 | * This version has limitted ability to report |
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55 | * possible occurence of deadlock. |
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56 | * |
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57 | * @param sl Pointer to spinlock_t structure. |
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58 | */ |
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1 | jermar | 59 | void spinlock_lock(spinlock_t *sl) |
60 | { |
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61 | int i = 0; |
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62 | __address caller = ((__u32 *) &sl)[-1]; |
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63 | |||
223 | jermar | 64 | preemption_disable(); |
1 | jermar | 65 | while (test_and_set(&sl->val)) { |
66 | if (i++ > 300000) { |
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15 | jermar | 67 | printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller); |
1 | jermar | 68 | i = 0; |
69 | } |
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70 | } |
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383 | jermar | 71 | |
72 | /* |
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73 | * Prevent critical section code from bleeding out this way up. |
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74 | */ |
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153 | jermar | 75 | CS_ENTER_BARRIER(); |
1 | jermar | 76 | |
77 | } |
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383 | jermar | 78 | |
1 | jermar | 79 | #else |
383 | jermar | 80 | |
81 | /** Lock spinlock |
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82 | * |
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83 | * Lock spinlock. |
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84 | * |
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85 | * @param sl Pointer to spinlock_t structure. |
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86 | */ |
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1 | jermar | 87 | void spinlock_lock(spinlock_t *sl) |
88 | { |
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223 | jermar | 89 | preemption_disable(); |
90 | |||
1 | jermar | 91 | /* |
92 | * Each architecture has its own efficient/recommended |
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93 | * implementation of spinlock. |
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94 | */ |
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95 | spinlock_arch(&sl->val); |
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383 | jermar | 96 | |
97 | /* |
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98 | * Prevent critical section code from bleeding out this way up. |
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99 | */ |
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153 | jermar | 100 | CS_ENTER_BARRIER(); |
1 | jermar | 101 | } |
102 | #endif |
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103 | |||
383 | jermar | 104 | /** Lock spinlock conditionally |
105 | * |
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106 | * Lock spinlock conditionally. |
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107 | * If the spinlock is not available at the moment, |
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108 | * signal failure. |
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109 | * |
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110 | * @param sl Pointer to spinlock_t structure. |
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111 | * |
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112 | * @return Zero on failure, non-zero otherwise. |
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113 | */ |
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1 | jermar | 114 | int spinlock_trylock(spinlock_t *sl) |
115 | { |
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153 | jermar | 116 | int rc; |
117 | |||
223 | jermar | 118 | preemption_disable(); |
153 | jermar | 119 | rc = !test_and_set(&sl->val); |
383 | jermar | 120 | |
121 | /* |
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122 | * Prevent critical section code from bleeding out this way up. |
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123 | */ |
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153 | jermar | 124 | CS_ENTER_BARRIER(); |
223 | jermar | 125 | |
126 | if (!rc) |
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127 | preemption_enable(); |
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153 | jermar | 128 | |
129 | return rc; |
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1 | jermar | 130 | } |
131 | |||
383 | jermar | 132 | /** Unlock spinlock |
133 | * |
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134 | * Unlock spinlock. |
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135 | * |
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136 | * @param sl Pointer to spinlock_t structure. |
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137 | */ |
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1 | jermar | 138 | void spinlock_unlock(spinlock_t *sl) |
139 | { |
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383 | jermar | 140 | ASSERT(sl->val != 0); |
141 | |||
142 | /* |
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143 | * Prevent critical section code from bleeding out this way down. |
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144 | */ |
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153 | jermar | 145 | CS_LEAVE_BARRIER(); |
383 | jermar | 146 | |
1 | jermar | 147 | sl->val = 0; |
223 | jermar | 148 | preemption_enable(); |
1 | jermar | 149 | } |
150 | |||
151 | #endif |