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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 genericproc
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Task management.
  36.  */
  37.  
  38. #include <main/uinit.h>
  39. #include <proc/thread.h>
  40. #include <proc/task.h>
  41. #include <proc/uarg.h>
  42. #include <mm/as.h>
  43. #include <mm/slab.h>
  44. #include <synch/spinlock.h>
  45. #include <arch.h>
  46. #include <panic.h>
  47. #include <adt/btree.h>
  48. #include <adt/list.h>
  49. #include <ipc/ipc.h>
  50. #include <security/cap.h>
  51. #include <memstr.h>
  52. #include <print.h>
  53. #include <lib/elf.h>
  54. #include <errno.h>
  55. #include <syscall/copy.h>
  56. #include <console/klog.h>
  57.  
  58. #ifndef LOADED_PROG_STACK_PAGES_NO
  59. #define LOADED_PROG_STACK_PAGES_NO 1
  60. #endif
  61.  
  62. /** Spinlock protecting the tasks_btree B+tree. */
  63. SPINLOCK_INITIALIZE(tasks_lock);
  64.  
  65. /** B+tree of active tasks.
  66.  *
  67.  * The task is guaranteed to exist after it was found in the tasks_btree as long as:
  68.  * @li the tasks_lock is held,
  69.  * @li the task's lock is held when task's lock is acquired before releasing tasks_lock or
  70.  * @li the task's refcount is greater than 0
  71.  *
  72.  */
  73. btree_t tasks_btree;
  74.  
  75. static task_id_t task_counter = 0;
  76.  
  77. static void ktaskclnp(void *arg);
  78. static void ktaskgc(void *arg);
  79.  
  80. /** Initialize tasks
  81.  *
  82.  * Initialize kernel tasks support.
  83.  *
  84.  */
  85. void task_init(void)
  86. {
  87.     TASK = NULL;
  88.     btree_create(&tasks_btree);
  89. }
  90.  
  91.  
  92. /** Create new task
  93.  *
  94.  * Create new task with no threads.
  95.  *
  96.  * @param as Task's address space.
  97.  * @param name Symbolic name.
  98.  *
  99.  * @return New task's structure
  100.  *
  101.  */
  102. task_t *task_create(as_t *as, char *name)
  103. {
  104.     ipl_t ipl;
  105.     task_t *ta;
  106.     int i;
  107.    
  108.     ta = (task_t *) malloc(sizeof(task_t), 0);
  109.  
  110.     task_create_arch(ta);
  111.  
  112.     spinlock_initialize(&ta->lock, "task_ta_lock");
  113.     list_initialize(&ta->th_head);
  114.     ta->as = as;
  115.     ta->name = name;
  116.     ta->main_thread = NULL;
  117.     ta->refcount = 0;
  118.     ta->context = CONTEXT;
  119.  
  120.     ta->capabilities = 0;
  121.     ta->accept_new_threads = true;
  122.     ta->cycles = 0;
  123.    
  124.     ipc_answerbox_init(&ta->answerbox);
  125.     for (i = 0; i < IPC_MAX_PHONES; i++)
  126.         ipc_phone_init(&ta->phones[i]);
  127.     if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context, ta->context)))
  128.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  129.     atomic_set(&ta->active_calls, 0);
  130.  
  131.     mutex_initialize(&ta->futexes_lock);
  132.     btree_create(&ta->futexes);
  133.    
  134.     ipl = interrupts_disable();
  135.  
  136.     /*
  137.      * Increment address space reference count.
  138.      * TODO: Reconsider the locking scheme.
  139.      */
  140.     mutex_lock(&as->lock);
  141.     as->refcount++;
  142.     mutex_unlock(&as->lock);
  143.  
  144.     spinlock_lock(&tasks_lock);
  145.  
  146.     ta->taskid = ++task_counter;
  147.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  148.  
  149.     spinlock_unlock(&tasks_lock);
  150.     interrupts_restore(ipl);
  151.  
  152.     return ta;
  153. }
  154.  
  155. /** Destroy task.
  156.  *
  157.  * @param t Task to be destroyed.
  158.  */
  159. void task_destroy(task_t *t)
  160. {
  161.     task_destroy_arch(t);
  162.     btree_destroy(&t->futexes);
  163.  
  164.     mutex_lock_active(&t->as->lock);
  165.     if (--t->as->refcount == 0) {
  166.         mutex_unlock(&t->as->lock);
  167.         as_destroy(t->as);
  168.         /*
  169.          * t->as is destroyed.
  170.          */
  171.     } else
  172.         mutex_unlock(&t->as->lock);
  173.    
  174.     free(t);
  175.     TASK = NULL;
  176. }
  177.  
  178. /** Create new task with 1 thread and run it
  179.  *
  180.  * @param program_addr Address of program executable image.
  181.  * @param name Program name.
  182.  *
  183.  * @return Task of the running program or NULL on error.
  184.  */
  185. task_t * task_run_program(void *program_addr, char *name)
  186. {
  187.     as_t *as;
  188.     as_area_t *a;
  189.     int rc;
  190.     thread_t *t1, *t2;
  191.     task_t *task;
  192.     uspace_arg_t *kernel_uarg;
  193.  
  194.     as = as_create(0);
  195.     ASSERT(as);
  196.  
  197.     rc = elf_load((elf_header_t *) program_addr, as);
  198.     if (rc != EE_OK) {
  199.         as_destroy(as);
  200.         return NULL;
  201.     }
  202.    
  203.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  204.     kernel_uarg->uspace_entry = (void *) ((elf_header_t *) program_addr)->e_entry;
  205.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  206.     kernel_uarg->uspace_thread_function = NULL;
  207.     kernel_uarg->uspace_thread_arg = NULL;
  208.     kernel_uarg->uspace_uarg = NULL;
  209.    
  210.     task = task_create(as, name);
  211.     ASSERT(task);
  212.  
  213.     /*
  214.      * Create the data as_area.
  215.      */
  216.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  217.         LOADED_PROG_STACK_PAGES_NO*PAGE_SIZE,
  218.         USTACK_ADDRESS, AS_AREA_ATTR_NONE, &anon_backend, NULL);
  219.  
  220.     /*
  221.      * Create the main thread.
  222.      */
  223.     t1 = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE, "uinit", false);
  224.     ASSERT(t1);
  225.    
  226.     /*
  227.      * Create killer thread for the new task.
  228.      */
  229.     t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc", true);
  230.     ASSERT(t2);
  231.     thread_ready(t2);
  232.  
  233.     thread_ready(t1);
  234.  
  235.     return task;
  236. }
  237.  
  238. /** Syscall for reading task ID from userspace.
  239.  *
  240.  * @param uspace_task_id Userspace address of 8-byte buffer where to store current task ID.
  241.  *
  242.  * @return 0 on success or an error code from @ref errno.h.
  243.  */
  244. unative_t sys_task_get_id(task_id_t *uspace_task_id)
  245. {
  246.     /*
  247.      * No need to acquire lock on TASK because taskid
  248.      * remains constant for the lifespan of the task.
  249.      */
  250.     return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid, sizeof(TASK->taskid));
  251. }
  252.  
  253. /** Find task structure corresponding to task ID.
  254.  *
  255.  * The tasks_lock must be already held by the caller of this function
  256.  * and interrupts must be disabled.
  257.  *
  258.  * @param id Task ID.
  259.  *
  260.  * @return Task structure address or NULL if there is no such task ID.
  261.  */
  262. task_t *task_find_by_id(task_id_t id)
  263. {
  264.     btree_node_t *leaf;
  265.    
  266.     return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
  267. }
  268.  
  269. /** Get accounting data of given task.
  270.  *
  271.  * Note that task_lock on @t must be already held and
  272.  * interrupts must be already disabled.
  273.  *
  274.  * @param t Pointer to thread.
  275.  *
  276.  */
  277. uint64_t task_get_accounting(task_t *t)
  278. {
  279.     /* Accumulated value of task */
  280.     uint64_t ret = t->cycles;
  281.    
  282.     /* Current values of threads */
  283.     link_t *cur;
  284.     for (cur = t->th_head.next; cur != &t->th_head; cur = cur->next) {
  285.         thread_t *thr = list_get_instance(cur, thread_t, th_link);
  286.        
  287.         spinlock_lock(&thr->lock);
  288.         /* Process only counted threads */
  289.         if (!thr->uncounted) {
  290.             if (thr == THREAD) /* Update accounting of current thread */
  291.                 thread_update_accounting();
  292.             ret += thr->cycles;
  293.         }
  294.         spinlock_unlock(&thr->lock);
  295.     }
  296.    
  297.     return ret;
  298. }
  299.  
  300. /** Kill task.
  301.  *
  302.  * @param id ID of the task to be killed.
  303.  *
  304.  * @return 0 on success or an error code from errno.h
  305.  */
  306. int task_kill(task_id_t id)
  307. {
  308.     ipl_t ipl;
  309.     task_t *ta;
  310.     thread_t *t;
  311.     link_t *cur;
  312.  
  313.     if (id == 1)
  314.         return EPERM;
  315.    
  316.     ipl = interrupts_disable();
  317.     spinlock_lock(&tasks_lock);
  318.  
  319.     if (!(ta = task_find_by_id(id))) {
  320.         spinlock_unlock(&tasks_lock);
  321.         interrupts_restore(ipl);
  322.         return ENOENT;
  323.     }
  324.  
  325.     spinlock_lock(&ta->lock);
  326.     ta->refcount++;
  327.     spinlock_unlock(&ta->lock);
  328.  
  329.     btree_remove(&tasks_btree, ta->taskid, NULL);
  330.     spinlock_unlock(&tasks_lock);
  331.    
  332.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp", true);
  333.    
  334.     spinlock_lock(&ta->lock);
  335.     ta->accept_new_threads = false;
  336.     ta->refcount--;
  337.  
  338.     /*
  339.      * Interrupt all threads except ktaskclnp.
  340.      */
  341.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  342.         thread_t *thr;
  343.         bool  sleeping = false;
  344.        
  345.         thr = list_get_instance(cur, thread_t, th_link);
  346.         if (thr == t)
  347.             continue;
  348.            
  349.         spinlock_lock(&thr->lock);
  350.         thr->interrupted = true;
  351.         if (thr->state == Sleeping)
  352.             sleeping = true;
  353.         spinlock_unlock(&thr->lock);
  354.        
  355.         if (sleeping)
  356.             waitq_interrupt_sleep(thr);
  357.     }
  358.    
  359.     spinlock_unlock(&ta->lock);
  360.     interrupts_restore(ipl);
  361.    
  362.     if (t)
  363.         thread_ready(t);
  364.  
  365.     return 0;
  366. }
  367.  
  368. /** Print task list */
  369. void task_print_list(void)
  370. {
  371.     link_t *cur;
  372.     ipl_t ipl;
  373.    
  374.     /* Messing with thread structures, avoid deadlock */
  375.     ipl = interrupts_disable();
  376.     spinlock_lock(&tasks_lock);
  377.    
  378.     printf("taskid name       ctx address    as         cycles     threads calls  callee\n");
  379.     printf("------ ---------- --- ---------- ---------- ---------- ------- ------ ------>\n");
  380.  
  381.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head; cur = cur->next) {
  382.         btree_node_t *node;
  383.         int i;
  384.        
  385.         node = list_get_instance(cur, btree_node_t, leaf_link);
  386.         for (i = 0; i < node->keys; i++) {
  387.             task_t *t;
  388.             int j;
  389.  
  390.             t = (task_t *) node->value[i];
  391.        
  392.             spinlock_lock(&t->lock);
  393.            
  394.             uint64_t cycles = task_get_accounting(t);
  395.             char suffix;
  396.            
  397.             if (cycles > 1000000000000000000LL) {
  398.                 cycles = cycles / 1000000000000000000LL;
  399.                 suffix = 'E';
  400.             } else if (cycles > 1000000000000LL) {
  401.                 cycles = cycles / 1000000000000LL;
  402.                 suffix = 'T';
  403.             } else if (cycles > 1000000LL) {
  404.                 cycles = cycles / 1000000LL;
  405.                 suffix = 'M';
  406.             } else
  407.                 suffix = ' ';
  408.            
  409.             printf("%-6lld %-10s %-3ld %#10zx %#10zx %9llu%c %7zd %6zd", t->taskid, t->name, t->context, t, t->as, cycles, suffix, t->refcount, atomic_get(&t->active_calls));
  410.             for (j = 0; j < IPC_MAX_PHONES; j++) {
  411.                 if (t->phones[j].callee)
  412.                     printf(" %zd:%#zx", j, t->phones[j].callee);
  413.             }
  414.             printf("\n");
  415.            
  416.             spinlock_unlock(&t->lock);
  417.         }
  418.     }
  419.  
  420.     spinlock_unlock(&tasks_lock);
  421.     interrupts_restore(ipl);
  422. }
  423.  
  424. /** Kernel thread used to cleanup the task after it is killed. */
  425. void ktaskclnp(void *arg)
  426. {
  427.     ipl_t ipl;
  428.     thread_t *t = NULL, *main_thread;
  429.     link_t *cur;
  430.     bool again;
  431.  
  432.     thread_detach(THREAD);
  433.  
  434. loop:
  435.     ipl = interrupts_disable();
  436.     spinlock_lock(&TASK->lock);
  437.    
  438.     main_thread = TASK->main_thread;
  439.    
  440.     /*
  441.      * Find a thread to join.
  442.      */
  443.     again = false;
  444.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  445.         t = list_get_instance(cur, thread_t, th_link);
  446.  
  447.         spinlock_lock(&t->lock);
  448.         if (t == THREAD) {
  449.             spinlock_unlock(&t->lock);
  450.             continue;
  451.         } else if (t == main_thread) {
  452.             spinlock_unlock(&t->lock);
  453.             continue;
  454.         } else if (t->join_type != None) {
  455.             spinlock_unlock(&t->lock);
  456.             again = true;
  457.             continue;
  458.         } else {
  459.             t->join_type = TaskClnp;
  460.             spinlock_unlock(&t->lock);
  461.             again = false;
  462.             break;
  463.         }
  464.     }
  465.    
  466.     spinlock_unlock(&TASK->lock);
  467.     interrupts_restore(ipl);
  468.    
  469.     if (again) {
  470.         /*
  471.          * Other cleanup (e.g. ktaskgc) is in progress.
  472.          */
  473.         scheduler();
  474.         goto loop;
  475.     }
  476.    
  477.     if (t != THREAD) {
  478.         ASSERT(t != main_thread);   /* uninit is joined and detached in ktaskgc */
  479.         thread_join(t);
  480.         thread_detach(t);
  481.         goto loop;  /* go for another thread */
  482.     }
  483.    
  484.     /*
  485.      * Now there are no other threads in this task
  486.      * and no new threads can be created.
  487.      */
  488.  
  489.     ipc_cleanup();
  490.     futex_cleanup();
  491.     klog_printf("Cleanup of task %lld completed.", TASK->taskid);
  492. }
  493.  
  494. /** Kernel thread used to kill the userspace task when its main thread exits.
  495.  *
  496.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  497.  * When this happens, the task is killed. In the meantime, exited threads
  498.  * are garbage collected.
  499.  *
  500.  * @param arg Pointer to the thread structure of the task's main thread.
  501.  */
  502. void ktaskgc(void *arg)
  503. {
  504.     thread_t *t = (thread_t *) arg;
  505. loop:  
  506.     /*
  507.      * Userspace threads cannot detach themselves,
  508.      * therefore the thread pointer is guaranteed to be valid.
  509.      */
  510.     if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) == ESYNCH_TIMEOUT) {  /* sleep uninterruptibly here! */
  511.         ipl_t ipl;
  512.         link_t *cur;
  513.         thread_t *thr = NULL;
  514.    
  515.         /*
  516.          * The join timed out. Try to do some garbage collection of Undead threads.
  517.          */
  518. more_gc:       
  519.         ipl = interrupts_disable();
  520.         spinlock_lock(&TASK->lock);
  521.        
  522.         for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  523.             thr = list_get_instance(cur, thread_t, th_link);
  524.             spinlock_lock(&thr->lock);
  525.             if (thr != t && thr->state == Undead && thr->join_type == None) {
  526.                 thr->join_type = TaskGC;
  527.                 spinlock_unlock(&thr->lock);
  528.                 break;
  529.             }
  530.             spinlock_unlock(&thr->lock);
  531.             thr = NULL;
  532.         }
  533.         spinlock_unlock(&TASK->lock);
  534.         interrupts_restore(ipl);
  535.        
  536.         if (thr) {
  537.             thread_join(thr);
  538.             thread_detach(thr);
  539.             scheduler();
  540.             goto more_gc;
  541.         }
  542.            
  543.         goto loop;
  544.     }
  545.     thread_detach(t);
  546.     task_kill(TASK->taskid);
  547. }
  548.  
  549. /** @}
  550.  */
  551.