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1 | jermar | 1 | /* |
2071 | jermar | 2 | * Copyright (c) 2001-2004 Jakub Jermar |
1 | jermar | 3 | * All rights reserved. |
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 | |||
1731 | jermar | 29 | /** @addtogroup time |
1702 | cejka | 30 | * @{ |
31 | */ |
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32 | |||
1264 | jermar | 33 | /** |
1702 | cejka | 34 | * @file |
1264 | jermar | 35 | * @brief High-level clock interrupt handler. |
36 | * |
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37 | * This file contains the clock() function which is the source |
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38 | * of preemption. It is also responsible for executing expired |
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39 | * timeouts. |
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40 | */ |
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41 | |||
1 | jermar | 42 | #include <time/clock.h> |
43 | #include <time/timeout.h> |
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44 | #include <config.h> |
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45 | #include <synch/spinlock.h> |
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46 | #include <synch/waitq.h> |
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47 | #include <func.h> |
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48 | #include <proc/scheduler.h> |
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49 | #include <cpu.h> |
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50 | #include <arch.h> |
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788 | jermar | 51 | #include <adt/list.h> |
1104 | jermar | 52 | #include <atomic.h> |
391 | jermar | 53 | #include <proc/thread.h> |
1434 | palkovsky | 54 | #include <sysinfo/sysinfo.h> |
3862 | rimsky | 55 | #include <arch/asm.h> |
1434 | palkovsky | 56 | #include <arch/barrier.h> |
2015 | jermar | 57 | #include <mm/frame.h> |
58 | #include <ddi/ddi.h> |
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1 | jermar | 59 | |
2275 | decky | 60 | /* Pointer to variable with uptime */ |
61 | uptime_t *uptime; |
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62 | |||
63 | /** Physical memory area of the real time clock */ |
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2015 | jermar | 64 | static parea_t clock_parea; |
65 | |||
1434 | palkovsky | 66 | /* Variable holding fragment of second, so that we would update |
67 | * seconds correctly |
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68 | */ |
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1780 | jermar | 69 | static unative_t secfrag = 0; |
1434 | palkovsky | 70 | |
71 | /** Initialize realtime clock counter |
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72 | * |
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73 | * The applications (and sometimes kernel) need to access accurate |
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74 | * information about realtime data. We allocate 1 page with these |
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75 | * data and update it periodically. |
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76 | */ |
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77 | void clock_counter_init(void) |
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78 | { |
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79 | void *faddr; |
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80 | |||
2015 | jermar | 81 | faddr = frame_alloc(ONE_FRAME, FRAME_ATOMIC); |
1434 | palkovsky | 82 | if (!faddr) |
83 | panic("Cannot allocate page for clock"); |
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84 | |||
2275 | decky | 85 | uptime = (uptime_t *) PA2KA(faddr); |
86 | |||
87 | uptime->seconds1 = 0; |
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88 | uptime->seconds2 = 0; |
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89 | uptime->useconds = 0; |
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1434 | palkovsky | 90 | |
2015 | jermar | 91 | clock_parea.pbase = (uintptr_t) faddr; |
2275 | decky | 92 | clock_parea.vbase = (uintptr_t) uptime; |
2015 | jermar | 93 | clock_parea.frames = 1; |
94 | clock_parea.cacheable = true; |
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95 | ddi_parea_register(&clock_parea); |
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96 | |||
97 | /* |
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98 | * Prepare information for the userspace so that it can successfully |
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99 | * physmem_map() the clock_parea. |
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100 | */ |
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101 | sysinfo_set_item_val("clock.cacheable", NULL, (unative_t) true); |
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102 | sysinfo_set_item_val("clock.faddr", NULL, (unative_t) faddr); |
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1434 | palkovsky | 103 | } |
104 | |||
105 | |||
106 | /** Update public counters |
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107 | * |
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108 | * Update it only on first processor |
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109 | * TODO: Do we really need so many write barriers? |
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110 | */ |
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111 | static void clock_update_counters(void) |
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112 | { |
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113 | if (CPU->id == 0) { |
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2275 | decky | 114 | secfrag += 1000000 / HZ; |
1434 | palkovsky | 115 | if (secfrag >= 1000000) { |
1438 | palkovsky | 116 | secfrag -= 1000000; |
2275 | decky | 117 | uptime->seconds1++; |
1434 | palkovsky | 118 | write_barrier(); |
2275 | decky | 119 | uptime->useconds = secfrag; |
1438 | palkovsky | 120 | write_barrier(); |
2275 | decky | 121 | uptime->seconds2 = uptime->seconds1; |
1434 | palkovsky | 122 | } else |
2275 | decky | 123 | uptime->useconds += 1000000 / HZ; |
1434 | palkovsky | 124 | } |
125 | } |
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126 | |||
107 | decky | 127 | /** Clock routine |
128 | * |
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129 | * Clock routine executed from clock interrupt handler |
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413 | jermar | 130 | * (assuming interrupts_disable()'d). Runs expired timeouts |
107 | decky | 131 | * and preemptive scheduling. |
132 | * |
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1 | jermar | 133 | */ |
134 | void clock(void) |
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135 | { |
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136 | link_t *l; |
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137 | timeout_t *h; |
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411 | jermar | 138 | timeout_handler_t f; |
1 | jermar | 139 | void *arg; |
1457 | jermar | 140 | count_t missed_clock_ticks = CPU->missed_clock_ticks; |
2745 | decky | 141 | unsigned int i; |
1 | jermar | 142 | |
143 | /* |
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144 | * To avoid lock ordering problems, |
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145 | * run all expired timeouts as you visit them. |
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146 | */ |
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1457 | jermar | 147 | for (i = 0; i <= missed_clock_ticks; i++) { |
1434 | palkovsky | 148 | clock_update_counters(); |
1431 | jermar | 149 | spinlock_lock(&CPU->timeoutlock); |
150 | while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
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151 | h = list_get_instance(l, timeout_t, link); |
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152 | spinlock_lock(&h->lock); |
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153 | if (h->ticks-- != 0) { |
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154 | spinlock_unlock(&h->lock); |
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155 | break; |
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156 | } |
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157 | list_remove(l); |
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158 | f = h->handler; |
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159 | arg = h->arg; |
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160 | timeout_reinitialize(h); |
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161 | spinlock_unlock(&h->lock); |
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162 | spinlock_unlock(&CPU->timeoutlock); |
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163 | |||
164 | f(arg); |
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165 | |||
166 | spinlock_lock(&CPU->timeoutlock); |
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1 | jermar | 167 | } |
15 | jermar | 168 | spinlock_unlock(&CPU->timeoutlock); |
1 | jermar | 169 | } |
1431 | jermar | 170 | CPU->missed_clock_ticks = 0; |
1 | jermar | 171 | |
172 | /* |
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15 | jermar | 173 | * Do CPU usage accounting and find out whether to preempt THREAD. |
1 | jermar | 174 | */ |
175 | |||
15 | jermar | 176 | if (THREAD) { |
1780 | jermar | 177 | uint64_t ticks; |
221 | jermar | 178 | |
15 | jermar | 179 | spinlock_lock(&CPU->lock); |
1457 | jermar | 180 | CPU->needs_relink += 1 + missed_clock_ticks; |
15 | jermar | 181 | spinlock_unlock(&CPU->lock); |
1 | jermar | 182 | |
15 | jermar | 183 | spinlock_lock(&THREAD->lock); |
1457 | jermar | 184 | if ((ticks = THREAD->ticks)) { |
185 | if (ticks >= 1 + missed_clock_ticks) |
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186 | THREAD->ticks -= 1 + missed_clock_ticks; |
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187 | else |
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188 | THREAD->ticks = 0; |
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189 | } |
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221 | jermar | 190 | spinlock_unlock(&THREAD->lock); |
191 | |||
192 | if (!ticks && !PREEMPTION_DISABLED) { |
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3742 | rimsky | 193 | #ifdef CONFIG_UDEBUG |
194 | istate_t *istate; |
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195 | #endif |
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1 | jermar | 196 | scheduler(); |
3665 | rimsky | 197 | #ifdef CONFIG_UDEBUG |
198 | /* |
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199 | * Give udebug chance to stop the thread |
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3742 | rimsky | 200 | * before it begins executing userspace code. |
3665 | rimsky | 201 | */ |
3742 | rimsky | 202 | istate = THREAD->udebug.uspace_state; |
203 | if (istate && istate_from_uspace(istate)) |
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3665 | rimsky | 204 | udebug_before_thread_runs(); |
205 | #endif |
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1 | jermar | 206 | } |
207 | } |
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208 | |||
209 | } |
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1702 | cejka | 210 | |
1731 | jermar | 211 | /** @} |
1702 | cejka | 212 | */ |