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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 | |||
1702 | cejka | 29 | /** @defgroup others Others |
30 | * @ingroup kernel |
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31 | * @{ |
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32 | * @} |
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33 | */ |
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34 | |||
1704 | cejka | 35 | /** @addtogroup generic generic |
1702 | cejka | 36 | * @{ |
37 | */ |
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38 | |||
1264 | jermar | 39 | /** |
1702 | cejka | 40 | * @file |
1264 | jermar | 41 | * @brief High-level clock interrupt handler. |
42 | * |
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43 | * This file contains the clock() function which is the source |
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44 | * of preemption. It is also responsible for executing expired |
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45 | * timeouts. |
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46 | */ |
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47 | |||
1 | jermar | 48 | #include <time/clock.h> |
49 | #include <time/timeout.h> |
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50 | #include <arch/types.h> |
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51 | #include <config.h> |
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52 | #include <synch/spinlock.h> |
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53 | #include <synch/waitq.h> |
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54 | #include <func.h> |
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55 | #include <proc/scheduler.h> |
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56 | #include <cpu.h> |
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57 | #include <arch.h> |
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788 | jermar | 58 | #include <adt/list.h> |
1104 | jermar | 59 | #include <atomic.h> |
391 | jermar | 60 | #include <proc/thread.h> |
1434 | palkovsky | 61 | #include <sysinfo/sysinfo.h> |
62 | #include <arch/barrier.h> |
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1 | jermar | 63 | |
1434 | palkovsky | 64 | /* Pointers to public variables with time */ |
65 | struct ptime { |
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1438 | palkovsky | 66 | __native seconds1; |
1434 | palkovsky | 67 | __native useconds; |
1438 | palkovsky | 68 | __native seconds2; |
1434 | palkovsky | 69 | }; |
70 | struct ptime *public_time; |
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71 | /* Variable holding fragment of second, so that we would update |
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72 | * seconds correctly |
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73 | */ |
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74 | static __native secfrag = 0; |
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75 | |||
76 | /** Initialize realtime clock counter |
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77 | * |
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78 | * The applications (and sometimes kernel) need to access accurate |
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79 | * information about realtime data. We allocate 1 page with these |
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80 | * data and update it periodically. |
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81 | * |
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82 | * |
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83 | */ |
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84 | void clock_counter_init(void) |
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85 | { |
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86 | void *faddr; |
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87 | |||
88 | faddr = (void *)PFN2ADDR(frame_alloc(0, FRAME_ATOMIC)); |
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89 | if (!faddr) |
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90 | panic("Cannot allocate page for clock"); |
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91 | |||
92 | public_time = (struct ptime *)PA2KA(faddr); |
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93 | |||
94 | /* TODO: We would need some arch dependent settings here */ |
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1438 | palkovsky | 95 | public_time->seconds1 = 0; |
96 | public_time->seconds2 = 0; |
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1434 | palkovsky | 97 | public_time->useconds = 0; |
98 | |||
99 | sysinfo_set_item_val("clock.faddr", NULL, (__native)faddr); |
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100 | } |
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101 | |||
102 | |||
103 | /** Update public counters |
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104 | * |
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105 | * Update it only on first processor |
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106 | * TODO: Do we really need so many write barriers? |
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107 | */ |
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108 | static void clock_update_counters(void) |
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109 | { |
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110 | if (CPU->id == 0) { |
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111 | secfrag += 1000000/HZ; |
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112 | if (secfrag >= 1000000) { |
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1438 | palkovsky | 113 | secfrag -= 1000000; |
114 | public_time->seconds1++; |
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1434 | palkovsky | 115 | write_barrier(); |
1438 | palkovsky | 116 | public_time->useconds = secfrag; |
117 | write_barrier(); |
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118 | public_time->seconds2 = public_time->seconds1; |
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1434 | palkovsky | 119 | } else |
120 | public_time->useconds += 1000000/HZ; |
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121 | } |
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122 | } |
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123 | |||
107 | decky | 124 | /** Clock routine |
125 | * |
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126 | * Clock routine executed from clock interrupt handler |
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413 | jermar | 127 | * (assuming interrupts_disable()'d). Runs expired timeouts |
107 | decky | 128 | * and preemptive scheduling. |
129 | * |
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1 | jermar | 130 | */ |
131 | void clock(void) |
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132 | { |
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133 | link_t *l; |
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134 | timeout_t *h; |
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411 | jermar | 135 | timeout_handler_t f; |
1 | jermar | 136 | void *arg; |
1457 | jermar | 137 | count_t missed_clock_ticks = CPU->missed_clock_ticks; |
1431 | jermar | 138 | int i; |
1 | jermar | 139 | |
140 | /* |
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141 | * To avoid lock ordering problems, |
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142 | * run all expired timeouts as you visit them. |
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143 | */ |
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1457 | jermar | 144 | for (i = 0; i <= missed_clock_ticks; i++) { |
1434 | palkovsky | 145 | clock_update_counters(); |
1431 | jermar | 146 | spinlock_lock(&CPU->timeoutlock); |
147 | while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
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148 | h = list_get_instance(l, timeout_t, link); |
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149 | spinlock_lock(&h->lock); |
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150 | if (h->ticks-- != 0) { |
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151 | spinlock_unlock(&h->lock); |
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152 | break; |
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153 | } |
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154 | list_remove(l); |
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155 | f = h->handler; |
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156 | arg = h->arg; |
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157 | timeout_reinitialize(h); |
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158 | spinlock_unlock(&h->lock); |
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159 | spinlock_unlock(&CPU->timeoutlock); |
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160 | |||
161 | f(arg); |
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162 | |||
163 | spinlock_lock(&CPU->timeoutlock); |
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1 | jermar | 164 | } |
15 | jermar | 165 | spinlock_unlock(&CPU->timeoutlock); |
1 | jermar | 166 | } |
1431 | jermar | 167 | CPU->missed_clock_ticks = 0; |
1 | jermar | 168 | |
169 | /* |
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15 | jermar | 170 | * Do CPU usage accounting and find out whether to preempt THREAD. |
1 | jermar | 171 | */ |
172 | |||
15 | jermar | 173 | if (THREAD) { |
221 | jermar | 174 | __u64 ticks; |
175 | |||
15 | jermar | 176 | spinlock_lock(&CPU->lock); |
1457 | jermar | 177 | CPU->needs_relink += 1 + missed_clock_ticks; |
15 | jermar | 178 | spinlock_unlock(&CPU->lock); |
1 | jermar | 179 | |
15 | jermar | 180 | spinlock_lock(&THREAD->lock); |
1457 | jermar | 181 | if ((ticks = THREAD->ticks)) { |
182 | if (ticks >= 1 + missed_clock_ticks) |
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183 | THREAD->ticks -= 1 + missed_clock_ticks; |
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184 | else |
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185 | THREAD->ticks = 0; |
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186 | } |
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221 | jermar | 187 | spinlock_unlock(&THREAD->lock); |
188 | |||
189 | if (!ticks && !PREEMPTION_DISABLED) { |
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1 | jermar | 190 | scheduler(); |
191 | } |
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192 | } |
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193 | |||
194 | } |
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1702 | cejka | 195 | |
196 | /** @} |
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197 | */ |
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198 |