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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.  
  128. /** Clock routine
  129.  *
  130.  * Clock routine executed from clock interrupt handler
  131.  * (assuming interrupts_disable()'d). Runs expired timeouts
  132.  * and preemptive scheduling.
  133.  *
  134.  */
  135. void clock(void)
  136. {
  137.     timeout_t *h;
  138.     timeout_handler_t f;
  139.     void *arg;
  140.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  141.     uint64_t *i = &(CPU->timeout_active_tree.base);
  142.     uint64_t absolute_clock_ticks = *i + missed_clock_ticks;
  143.     avltree_node_t *expnode;
  144.  
  145.     /*
  146.      * To avoid lock ordering problems,
  147.      * run all expired timeouts as you visit them.
  148.      */
  149.  
  150.     for (; *i <= absolute_clock_ticks; (*i)++) {
  151.         /*
  152.          * Basetime is encreased by missed clock ticks + 1 !!
  153.          */
  154.        
  155.         clock_update_counters();
  156.         spinlock_lock(&CPU->timeoutlock);
  157.    
  158.    
  159.         /*
  160.          * Check whether first timeout (with the smallest key in the tree) time out. If so perform
  161.          * callback function and try next timeout (more timeouts can have same timeout).
  162.          */
  163.         while ((expnode = avltree_find_min(&CPU->timeout_active_tree)) != NULL) {
  164.             h = avltree_get_instance(expnode,timeout_t,node);
  165.             spinlock_lock(&h->lock);
  166.             if (expnode->key != *i) {
  167.                 spinlock_unlock(&h->lock);
  168.                 break;
  169.             }
  170.            
  171.             /*
  172.              * Delete minimal key from the tree and repair tree structure in
  173.              * logarithmic time.
  174.              */
  175.             avltree_delete_min(&CPU->timeout_active_tree);
  176.  
  177.             f = h->handler;
  178.             arg = h->arg;
  179.             timeout_reinitialize(h);
  180.             spinlock_unlock(&h->lock); 
  181.             spinlock_unlock(&CPU->timeoutlock);
  182.  
  183.             f(arg);
  184.  
  185.             spinlock_lock(&CPU->timeoutlock);
  186.         }
  187.         spinlock_unlock(&CPU->timeoutlock);
  188.     }
  189.  
  190.     CPU->missed_clock_ticks = 0;
  191.  
  192.     /*
  193.      * Do CPU usage accounting and find out whether to preempt THREAD.
  194.      */
  195.     if (THREAD) {
  196.         uint64_t ticks;
  197.        
  198.         spinlock_lock(&CPU->lock);
  199.         CPU->needs_relink += 1 + missed_clock_ticks;
  200.         spinlock_unlock(&CPU->lock);   
  201.    
  202.         spinlock_lock(&THREAD->lock);
  203.         if ((ticks = THREAD->ticks)) {
  204.             if (ticks >= 1 + missed_clock_ticks)
  205.                 THREAD->ticks -= 1 + missed_clock_ticks;
  206.             else
  207.                 THREAD->ticks = 0;
  208.         }
  209.         spinlock_unlock(&THREAD->lock);
  210.        
  211.         if (!ticks && !PREEMPTION_DISABLED) {
  212.             scheduler();
  213.         }
  214.     }
  215. }
  216.  
  217. #elif defined CONFIG_TIMEOUT_EXTAVL_TREE
  218.  
  219. /** Clock routine
  220.  *
  221.  * Clock routine executed from clock interrupt handler
  222.  * (assuming interrupts_disable()'d). Runs expired timeouts
  223.  * and preemptive scheduling.
  224.  *
  225.  */
  226. void clock(void)
  227. {
  228.     timeout_t *h;
  229.     timeout_handler_t f;
  230.     void *arg;
  231.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  232.     uint64_t *i = &(CPU->timeout_active_tree.base);
  233.     uint64_t absolute_clock_ticks = *i + missed_clock_ticks;
  234.     extavltree_node_t *expnode;
  235.  
  236.     /*
  237.      * To avoid lock ordering problems,
  238.      * run all expired timeouts as you visit them.
  239.      */
  240.  
  241.     for (; *i <= absolute_clock_ticks; (*i)++) {
  242.         /*
  243.          * Basetime is encreased by missed clock ticks + 1 !!
  244.          */
  245.        
  246.         clock_update_counters();
  247.         spinlock_lock(&CPU->timeoutlock);
  248.        
  249.         /*
  250.          * Check whether first timeout in list time out. If so perform callback function and try
  251.          * next timeout (more timeouts can have same timeout).
  252.          */
  253.         while ((expnode = CPU->timeout_active_tree.head.next) != &(CPU->timeout_active_tree.head)) {
  254.             h = extavltree_get_instance(expnode,timeout_t,node);
  255.             spinlock_lock(&h->lock);
  256.             if (expnode->key != *i) {
  257.                 spinlock_unlock(&h->lock);
  258.                 break;
  259.             }
  260.            
  261.             /*
  262.              * Delete first node in the list and repair tree structure in
  263.              * constant time.
  264.              */
  265.             extavltree_delete_min(&CPU->timeout_active_tree);
  266.  
  267.             f = h->handler;
  268.             arg = h->arg;
  269.             timeout_reinitialize(h);
  270.             spinlock_unlock(&h->lock); 
  271.             spinlock_unlock(&CPU->timeoutlock);
  272.  
  273.             f(arg);
  274.  
  275.             spinlock_lock(&CPU->timeoutlock);
  276.         }
  277.         spinlock_unlock(&CPU->timeoutlock);
  278.     }
  279.  
  280.     CPU->missed_clock_ticks = 0;
  281.  
  282.     /*
  283.      * Do CPU usage accounting and find out whether to preempt THREAD.
  284.      */
  285.     if (THREAD) {
  286.         uint64_t ticks;
  287.        
  288.         spinlock_lock(&CPU->lock);
  289.         CPU->needs_relink += 1 + missed_clock_ticks;
  290.         spinlock_unlock(&CPU->lock);   
  291.    
  292.         spinlock_lock(&THREAD->lock);
  293.         if ((ticks = THREAD->ticks)) {
  294.             if (ticks >= 1 + missed_clock_ticks)
  295.                 THREAD->ticks -= 1 + missed_clock_ticks;
  296.             else
  297.                 THREAD->ticks = 0;
  298.         }
  299.         spinlock_unlock(&THREAD->lock);
  300.        
  301.         if (!ticks && !PREEMPTION_DISABLED) {
  302.             scheduler();
  303.         }
  304.     }
  305. }
  306.  
  307. #elif defined CONFIG_TIMEOUT_EXTAVLREL_TREE
  308.  
  309. /** Clock routine
  310.  *
  311.  * Clock routine executed from clock interrupt handler
  312.  * (assuming interrupts_disable()'d). Runs expired timeouts
  313.  * and preemptive scheduling.
  314.  *
  315.  */
  316. void clock(void)
  317. {
  318.     extavlreltree_node_t *expnode;
  319.     timeout_t *h;
  320.     timeout_handler_t f;
  321.     void *arg;
  322.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  323.     int i;
  324.  
  325.     /*
  326.      * To avoid lock ordering problems,
  327.      * run all expired timeouts as you visit them.
  328.      */
  329.     for (i = 0; i <= missed_clock_ticks; i++) {
  330.         clock_update_counters();
  331.         spinlock_lock(&CPU->timeoutlock);
  332.  
  333.         /*
  334.          * Check whether first timeout in list time out. If so perform callback function and try
  335.          * next timeout (more timeouts can have same timeout).
  336.          */
  337.         while ((expnode = CPU->timeout_active_tree.head.next) != &(CPU->timeout_active_tree.head)) {
  338.             h = extavlreltree_get_instance(expnode,timeout_t,node);
  339.             spinlock_lock(&h->lock);
  340.             if (expnode->key != 0) {
  341.                 expnode->key--;
  342.                 spinlock_unlock(&h->lock);
  343.                 break;
  344.             }
  345.            
  346.             /*
  347.              * Delete first node in the list and repair tree structure in
  348.              * constant time. Be careful of expnode's key, it must be 0!
  349.              */
  350.             extavlreltree_delete_min(&CPU->timeout_active_tree);
  351.            
  352.             f = h->handler;
  353.             arg = h->arg;
  354.             timeout_reinitialize(h);
  355.             spinlock_unlock(&h->lock); 
  356.             spinlock_unlock(&CPU->timeoutlock);
  357.  
  358.             f(arg);
  359.  
  360.             spinlock_lock(&CPU->timeoutlock);
  361.         }
  362.         spinlock_unlock(&CPU->timeoutlock);
  363.     }
  364.     CPU->missed_clock_ticks = 0;
  365.  
  366.     /*
  367.      * Do CPU usage accounting and find out whether to preempt THREAD.
  368.      */
  369.  
  370.     if (THREAD) {
  371.         uint64_t ticks;
  372.        
  373.         spinlock_lock(&CPU->lock);
  374.         CPU->needs_relink += 1 + missed_clock_ticks;
  375.         spinlock_unlock(&CPU->lock);   
  376.    
  377.         spinlock_lock(&THREAD->lock);
  378.         if ((ticks = THREAD->ticks)) {
  379.             if (ticks >= 1 + missed_clock_ticks)
  380.                 THREAD->ticks -= 1 + missed_clock_ticks;
  381.             else
  382.                 THREAD->ticks = 0;
  383.         }
  384.         spinlock_unlock(&THREAD->lock);
  385.        
  386.         if (!ticks && !PREEMPTION_DISABLED) {
  387.             scheduler();
  388.         }
  389.     }
  390. }
  391.  
  392.  
  393.  
  394. #else
  395.  
  396.  
  397. /** Clock routine
  398.  *
  399.  * Clock routine executed from clock interrupt handler
  400.  * (assuming interrupts_disable()'d). Runs expired timeouts
  401.  * and preemptive scheduling.
  402.  *
  403.  */
  404. void clock(void)
  405. {
  406.     link_t *l;
  407.     timeout_t *h;
  408.     timeout_handler_t f;
  409.     void *arg;
  410.     count_t missed_clock_ticks = CPU->missed_clock_ticks;
  411.     int i;
  412.  
  413.     /*
  414.      * To avoid lock ordering problems,
  415.      * run all expired timeouts as you visit them.
  416.      */
  417.     for (i = 0; i <= missed_clock_ticks; i++) {
  418.         clock_update_counters();
  419.         spinlock_lock(&CPU->timeoutlock);
  420.         while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) {
  421.             h = list_get_instance(l, timeout_t, link);
  422.             spinlock_lock(&h->lock);
  423.             if (h->ticks-- != 0) {
  424.                 spinlock_unlock(&h->lock);
  425.                 break;
  426.             }
  427.             list_remove(l);
  428.             f = h->handler;
  429.             arg = h->arg;
  430.             timeout_reinitialize(h);
  431.             spinlock_unlock(&h->lock); 
  432.             spinlock_unlock(&CPU->timeoutlock);
  433.  
  434.             f(arg);
  435.  
  436.             spinlock_lock(&CPU->timeoutlock);
  437.         }
  438.         spinlock_unlock(&CPU->timeoutlock);
  439.     }
  440.     CPU->missed_clock_ticks = 0;
  441.  
  442.     /*
  443.      * Do CPU usage accounting and find out whether to preempt THREAD.
  444.      */
  445.  
  446.     if (THREAD) {
  447.         uint64_t ticks;
  448.        
  449.         spinlock_lock(&CPU->lock);
  450.         CPU->needs_relink += 1 + missed_clock_ticks;
  451.         spinlock_unlock(&CPU->lock);   
  452.    
  453.         spinlock_lock(&THREAD->lock);
  454.         if ((ticks = THREAD->ticks)) {
  455.             if (ticks >= 1 + missed_clock_ticks)
  456.                 THREAD->ticks -= 1 + missed_clock_ticks;
  457.             else
  458.                 THREAD->ticks = 0;
  459.         }
  460.         spinlock_unlock(&THREAD->lock);
  461.        
  462.         if (!ticks && !PREEMPTION_DISABLED) {
  463.             scheduler();
  464.         }
  465.     }
  466. }
  467.  
  468. #endif
  469. /** @}
  470.  */
  471.