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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup time
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   High-level clock interrupt handler.
  36.  *
  37.  * This file contains the clock() function which is the source
  38.  * of preemption. It is also responsible for executing expired
  39.  * timeouts.
  40.  */
  41.  
  42. #include <time/clock.h>
  43. #include <time/timeout.h>
  44. #include <config.h>
  45. #include <synch/spinlock.h>
  46. #include <synch/waitq.h>
  47. #include <func.h>
  48. #include <proc/scheduler.h>
  49. #include <cpu.h>
  50. #include <arch.h>
  51. #include <adt/list.h>
  52. #include <atomic.h>
  53. #include <proc/thread.h>
  54. #include <sysinfo/sysinfo.h>
  55. #include <arch/barrier.h>
  56. #include <mm/frame.h>
  57. #include <ddi/ddi.h>
  58.  
  59. /* Pointer to variable with uptime */
  60. uptime_t *uptime;
  61.  
  62. /** Physical memory area of the real time clock */
  63. static parea_t clock_parea;
  64.  
  65. /* Variable holding fragment of second, so that we would update
  66.  * seconds correctly
  67.  */
  68. static unative_t secfrag = 0;
  69.  
  70. /** Initialize realtime clock counter
  71.  *
  72.  * The applications (and sometimes kernel) need to access accurate
  73.  * information about realtime data. We allocate 1 page with these
  74.  * data and update it periodically.
  75.  */
  76. void clock_counter_init(void)
  77. {
  78.     void *faddr;
  79.  
  80.     faddr = frame_alloc(ONE_FRAME, FRAME_ATOMIC);
  81.     if (!faddr)
  82.         panic("Cannot allocate page for clock");
  83.    
  84.     uptime = (uptime_t *) PA2KA(faddr);
  85.    
  86.     uptime->seconds1 = 0;
  87.     uptime->seconds2 = 0;
  88.     uptime->useconds = 0;
  89.  
  90.     clock_parea.pbase = (uintptr_t) faddr;
  91.     clock_parea.vbase = (uintptr_t) uptime;
  92.     clock_parea.frames = 1;
  93.     clock_parea.cacheable = true;
  94.     ddi_parea_register(&clock_parea);
  95.  
  96.     /*
  97.      * Prepare information for the userspace so that it can successfully
  98.      * physmem_map() the clock_parea.
  99.      */
  100.     sysinfo_set_item_val("clock.cacheable", NULL, (unative_t) true);
  101.     sysinfo_set_item_val("clock.faddr", NULL, (unative_t) faddr);
  102. }
  103.  
  104.  
  105. /** Update public counters
  106.  *
  107.  * Update it only on first processor
  108.  * TODO: Do we really need so many write barriers?
  109.  */
  110. static void clock_update_counters(void)
  111. {
  112.     if (CPU->id == 0) {
  113.         secfrag += 1000000 / HZ;
  114.         if (secfrag >= 1000000) {
  115.             secfrag -= 1000000;
  116.             uptime->seconds1++;
  117.             write_barrier();
  118.             uptime->useconds = secfrag;
  119.             write_barrier();
  120.             uptime->seconds2 = uptime->seconds1;
  121.         } else
  122.             uptime->useconds += 1000000 / HZ;
  123.     }
  124. }
  125.  
  126. #if defined CONFIG_TIMEOUT_AVL_TREE || \
  127.     defined CONFIG_TIMEOUT_EXTAVL_TREE
  128.  
  129. /** Clock routine
  130.  *
  131.  * Clock routine executed from clock interrupt handler
  132.  * (assuming interrupts_disable()'d). Runs expired timeouts
  133.  * and preemptive scheduling.
  134.  *
  135.  */
  136. void clock(void)
  137. {
  138.     timeout_t *h;
  139.     timeout_handler_t f;
  140.     void *arg;
  141.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  142.     uint64_t *i = &(CPU->timeout_active_tree.base);
  143.     uint64_t absolute_clock_ticks = *i + missed_clock_ticks;
  144. #if defined CONFIG TIMEOUT_AVL_TREE
  145.     avltree_node_t *expnode;
  146. #elif defined CONFIG_TIMEOUT_EXTAVL_TREE
  147.     extavltree_node_t *expnode;
  148. #endif
  149.  
  150.     /*
  151.      * To avoid lock ordering problems,
  152.      * run all expired timeouts as you visit them.
  153.      */
  154.  
  155.     for (; *i <= absolute_clock_ticks; (*i)++) {
  156.         /*
  157.          * Basetime is encreased by missed clock ticks + 1 !!
  158.          */
  159.        
  160.         clock_update_counters();
  161.         spinlock_lock(&CPU->timeoutlock);
  162.        
  163.         /*
  164.          * Check whether first timeout in list time out. If so perform callback function and try
  165.          * next timeout (more timeouts can have same timeout).
  166.          */
  167.         while ((expnode = CPU->timeout_active_tree.head.next) != &(CPU->timeout_active_tree.head)) {
  168.             h = extavltree_get_instance(expnode,timeout_t,node);
  169.             spinlock_lock(&h->lock);
  170.             if (expnode->key != *i) {
  171.                 spinlock_unlock(&h->lock);
  172.                 break;
  173.             }
  174.            
  175.             /*
  176.              * Delete first node in the list and repair tree structure in
  177.              * constant time.
  178.              */
  179. #if defined CONFIG TIMEOUT_AVL_TREE
  180.             avltree_delete_min(&CPU->timeout_active_tree);
  181. #elif defined CONFIG_TIMEOUT_EXTAVL_TREE
  182.             extavltree_delete_min(&CPU->timeout_active_tree);
  183. #endif
  184.  
  185.             f = h->handler;
  186.             arg = h->arg;
  187.             timeout_reinitialize(h);
  188.             spinlock_unlock(&h->lock); 
  189.             spinlock_unlock(&CPU->timeoutlock);
  190.  
  191.             f(arg);
  192.  
  193.             spinlock_lock(&CPU->timeoutlock);
  194.         }
  195.         spinlock_unlock(&CPU->timeoutlock);
  196.     }
  197.  
  198.     CPU->missed_clock_ticks = 0;
  199.  
  200.     /*
  201.      * Do CPU usage accounting and find out whether to preempt THREAD.
  202.      */
  203.     if (THREAD) {
  204.         uint64_t ticks;
  205.        
  206.         spinlock_lock(&CPU->lock);
  207.         CPU->needs_relink += 1 + missed_clock_ticks;
  208.         spinlock_unlock(&CPU->lock);   
  209.    
  210.         spinlock_lock(&THREAD->lock);
  211.         if ((ticks = THREAD->ticks)) {
  212.             if (ticks >= 1 + missed_clock_ticks)
  213.                 THREAD->ticks -= 1 + missed_clock_ticks;
  214.             else
  215.                 THREAD->ticks = 0;
  216.         }
  217.         spinlock_unlock(&THREAD->lock);
  218.        
  219.         if (!ticks && !PREEMPTION_DISABLED) {
  220.             scheduler();
  221.         }
  222.     }
  223. }
  224.  
  225. #elif defined CONFIG_TIMEOUT_EXTAVLREL_TREE
  226.  
  227. /** Clock routine
  228.  *
  229.  * Clock routine executed from clock interrupt handler
  230.  * (assuming interrupts_disable()'d). Runs expired timeouts
  231.  * and preemptive scheduling.
  232.  *
  233.  */
  234. void clock(void)
  235. {
  236.     extavltree_node_t *expnode;
  237.     timeout_t *h;
  238.     timeout_handler_t f;
  239.     void *arg;
  240.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  241.     int i;
  242.  
  243.     /*
  244.      * To avoid lock ordering problems,
  245.      * run all expired timeouts as you visit them.
  246.      */
  247.     for (i = 0; i <= missed_clock_ticks; i++) {
  248.         clock_update_counters();
  249.         spinlock_lock(&CPU->timeoutlock);
  250.  
  251.         /*
  252.          * Check whether first timeout in list time out. If so perform callback function and try
  253.          * next timeout (more timeouts can have same timeout).
  254.          */
  255.         while ((expnode = CPU->timeout_active_tree.head.next) != &(CPU->timeout_active_tree.head)) {
  256.             h = list_get_instance(l, timeout_t, link);
  257.             spinlock_lock(&h->lock);
  258.             if (expnode->key != 0) {
  259.                 expnode->key--;
  260.                 spinlock_unlock(&h->lock);
  261.                 break;
  262.             }
  263.            
  264.             /*
  265.              * Delete first node in the list and repair tree structure in
  266.              * constant time. Be careful of expnode's key, it must be 0!
  267.              */
  268.             extavltree_delete_min(&CPU->timeout_active_tree);
  269.            
  270.             f = h->handler;
  271.             arg = h->arg;
  272.             timeout_reinitialize(h);
  273.             spinlock_unlock(&h->lock); 
  274.             spinlock_unlock(&CPU->timeoutlock);
  275.  
  276.             f(arg);
  277.  
  278.             spinlock_lock(&CPU->timeoutlock);
  279.         }
  280.         spinlock_unlock(&CPU->timeoutlock);
  281.     }
  282.     CPU->missed_clock_ticks = 0;
  283.  
  284.     /*
  285.      * Do CPU usage accounting and find out whether to preempt THREAD.
  286.      */
  287.  
  288.     if (THREAD) {
  289.         uint64_t ticks;
  290.        
  291.         spinlock_lock(&CPU->lock);
  292.         CPU->needs_relink += 1 + missed_clock_ticks;
  293.         spinlock_unlock(&CPU->lock);   
  294.    
  295.         spinlock_lock(&THREAD->lock);
  296.         if ((ticks = THREAD->ticks)) {
  297.             if (ticks >= 1 + missed_clock_ticks)
  298.                 THREAD->ticks -= 1 + missed_clock_ticks;
  299.             else
  300.                 THREAD->ticks = 0;
  301.         }
  302.         spinlock_unlock(&THREAD->lock);
  303.        
  304.         if (!ticks && !PREEMPTION_DISABLED) {
  305.             scheduler();
  306.         }
  307.     }
  308. }
  309.  
  310.  
  311.  
  312. #else
  313.  
  314.  
  315. /** Clock routine
  316.  *
  317.  * Clock routine executed from clock interrupt handler
  318.  * (assuming interrupts_disable()'d). Runs expired timeouts
  319.  * and preemptive scheduling.
  320.  *
  321.  */
  322. void clock(void)
  323. {
  324.     link_t *l;
  325.     timeout_t *h;
  326.     timeout_handler_t f;
  327.     void *arg;
  328.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  329.     int i;
  330.  
  331.     /*
  332.      * To avoid lock ordering problems,
  333.      * run all expired timeouts as you visit them.
  334.      */
  335.     for (i = 0; i <= missed_clock_ticks; i++) {
  336.         clock_update_counters();
  337.         spinlock_lock(&CPU->timeoutlock);
  338.         while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) {
  339.             h = list_get_instance(l, timeout_t, link);
  340.             spinlock_lock(&h->lock);
  341.             if (h->ticks-- != 0) {
  342.                 spinlock_unlock(&h->lock);
  343.                 break;
  344.             }
  345.             list_remove(l);
  346.             f = h->handler;
  347.             arg = h->arg;
  348.             timeout_reinitialize(h);
  349.             spinlock_unlock(&h->lock); 
  350.             spinlock_unlock(&CPU->timeoutlock);
  351.  
  352.             f(arg);
  353.  
  354.             spinlock_lock(&CPU->timeoutlock);
  355.         }
  356.         spinlock_unlock(&CPU->timeoutlock);
  357.     }
  358.     CPU->missed_clock_ticks = 0;
  359.  
  360.     /*
  361.      * Do CPU usage accounting and find out whether to preempt THREAD.
  362.      */
  363.  
  364.     if (THREAD) {
  365.         uint64_t ticks;
  366.        
  367.         spinlock_lock(&CPU->lock);
  368.         CPU->needs_relink += 1 + missed_clock_ticks;
  369.         spinlock_unlock(&CPU->lock);   
  370.    
  371.         spinlock_lock(&THREAD->lock);
  372.         if ((ticks = THREAD->ticks)) {
  373.             if (ticks >= 1 + missed_clock_ticks)
  374.                 THREAD->ticks -= 1 + missed_clock_ticks;
  375.             else
  376.                 THREAD->ticks = 0;
  377.         }
  378.         spinlock_unlock(&THREAD->lock);
  379.        
  380.         if (!ticks && !PREEMPTION_DISABLED) {
  381.             scheduler();
  382.         }
  383.     }
  384. }
  385.  
  386. #endif
  387. /** @}
  388.  */
  389.