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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 <atomic.h>
  45. #include <synch/spinlock.h>
  46. #include <synch/waitq.h>
  47. #include <arch.h>
  48. #include <panic.h>
  49. #include <adt/btree.h>
  50. #include <adt/list.h>
  51. #include <ipc/ipc.h>
  52. #include <security/cap.h>
  53. #include <memstr.h>
  54. #include <print.h>
  55. #include <lib/elf.h>
  56. #include <errno.h>
  57. #include <func.h>
  58. #include <syscall/copy.h>
  59. #include <console/klog.h>
  60.  
  61. #ifndef LOADED_PROG_STACK_PAGES_NO
  62. #define LOADED_PROG_STACK_PAGES_NO 1
  63. #endif
  64.  
  65. /** Spinlock protecting the tasks_btree B+tree. */
  66. SPINLOCK_INITIALIZE(tasks_lock);
  67.  
  68. /** B+tree of active tasks.
  69.  *
  70.  * The task is guaranteed to exist after it was found in the tasks_btree as
  71.  * long as:
  72.  * @li the tasks_lock is held,
  73.  * @li the task's lock is held when task's lock is acquired before releasing
  74.  *     tasks_lock or
  75.  * @li the task's refcount is greater than 0
  76.  *
  77.  */
  78. btree_t tasks_btree;
  79.  
  80. static task_id_t task_counter = 0;
  81.  
  82. static void ktaskclnp(void *arg);
  83. static void ktaskgc(void *arg);
  84.  
  85. /** Initialize tasks
  86.  *
  87.  * Initialize kernel tasks support.
  88.  *
  89.  */
  90. void task_init(void)
  91. {
  92.     TASK = NULL;
  93.     btree_create(&tasks_btree);
  94. }
  95.  
  96.  
  97. /** Create new task
  98.  *
  99.  * Create new task with no threads.
  100.  *
  101.  * @param as Task's address space.
  102.  * @param name Symbolic name.
  103.  *
  104.  * @return New task's structure
  105.  *
  106.  */
  107. task_t *task_create(as_t *as, char *name)
  108. {
  109.     ipl_t ipl;
  110.     task_t *ta;
  111.     int i;
  112.    
  113.     ta = (task_t *) malloc(sizeof(task_t), 0);
  114.  
  115.     task_create_arch(ta);
  116.  
  117.     spinlock_initialize(&ta->lock, "task_ta_lock");
  118.     list_initialize(&ta->th_head);
  119.     ta->as = as;
  120.     ta->name = name;
  121.     ta->main_thread = NULL;
  122.     ta->refcount = 0;
  123.     ta->context = CONTEXT;
  124.  
  125.     ta->capabilities = 0;
  126.     ta->accept_new_threads = true;
  127.     ta->cycles = 0;
  128.    
  129.     ipc_answerbox_init(&ta->answerbox);
  130.     for (i = 0; i < IPC_MAX_PHONES; i++)
  131.         ipc_phone_init(&ta->phones[i]);
  132.     if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context,
  133.         ta->context)))
  134.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  135.     atomic_set(&ta->active_calls, 0);
  136.  
  137.     mutex_initialize(&ta->futexes_lock);
  138.     btree_create(&ta->futexes);
  139.    
  140.     ipl = interrupts_disable();
  141.  
  142.     /*
  143.      * Increment address space reference count.
  144.      */
  145.     atomic_inc(&as->refcount);
  146.  
  147.     spinlock_lock(&tasks_lock);
  148.  
  149.     ta->taskid = ++task_counter;
  150.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  151.  
  152.     spinlock_unlock(&tasks_lock);
  153.     interrupts_restore(ipl);
  154.  
  155.     return ta;
  156. }
  157.  
  158. /** Destroy task.
  159.  *
  160.  * @param t Task to be destroyed.
  161.  */
  162. void task_destroy(task_t *t)
  163. {
  164.     task_destroy_arch(t);
  165.     btree_destroy(&t->futexes);
  166.  
  167.     if (atomic_predec(&t->as->refcount) == 0)
  168.         as_destroy(t->as);
  169.    
  170.     free(t);
  171.     TASK = NULL;
  172. }
  173.  
  174. /** Create new task with 1 thread and run it
  175.  *
  176.  * @param program_addr Address of program executable image.
  177.  * @param name Program name.
  178.  *
  179.  * @return Task of the running program or NULL on error.
  180.  */
  181. task_t * task_run_program(void *program_addr, char *name)
  182. {
  183.     as_t *as;
  184.     as_area_t *a;
  185.     int rc;
  186.     thread_t *t1, *t2;
  187.     task_t *task;
  188.     uspace_arg_t *kernel_uarg;
  189.  
  190.     as = as_create(0);
  191.     ASSERT(as);
  192.  
  193.     rc = elf_load((elf_header_t *) program_addr, as);
  194.     if (rc != EE_OK) {
  195.         as_destroy(as);
  196.         return NULL;
  197.     }
  198.    
  199.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  200.     kernel_uarg->uspace_entry =
  201.         (void *) ((elf_header_t *) program_addr)->e_entry;
  202.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  203.     kernel_uarg->uspace_thread_function = NULL;
  204.     kernel_uarg->uspace_thread_arg = NULL;
  205.     kernel_uarg->uspace_uarg = NULL;
  206.    
  207.     task = task_create(as, name);
  208.     ASSERT(task);
  209.  
  210.     /*
  211.      * Create the data as_area.
  212.      */
  213.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  214.         LOADED_PROG_STACK_PAGES_NO * PAGE_SIZE, USTACK_ADDRESS,
  215.         AS_AREA_ATTR_NONE, &anon_backend, NULL);
  216.  
  217.     /*
  218.      * Create the main thread.
  219.      */
  220.     t1 = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
  221.         "uinit", false);
  222.     ASSERT(t1);
  223.    
  224.     /*
  225.      * Create killer thread for the new task.
  226.      */
  227.     t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc", true);
  228.     ASSERT(t2);
  229.     thread_ready(t2);
  230.  
  231.     thread_ready(t1);
  232.  
  233.     return task;
  234. }
  235.  
  236. /** Syscall for reading task ID from userspace.
  237.  *
  238.  * @param uspace_task_id Userspace address of 8-byte buffer where to store
  239.  * current task ID.
  240.  *
  241.  * @return 0 on success or an error code from @ref errno.h.
  242.  */
  243. unative_t sys_task_get_id(task_id_t *uspace_task_id)
  244. {
  245.     /*
  246.      * No need to acquire lock on TASK because taskid
  247.      * remains constant for the lifespan of the task.
  248.      */
  249.     return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid,
  250.         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 of '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) {
  291.                 /* Update accounting of current thread */
  292.                 thread_update_accounting();
  293.             }
  294.             ret += thr->cycles;
  295.         }
  296.         spinlock_unlock(&thr->lock);
  297.     }
  298.    
  299.     return ret;
  300. }
  301.  
  302. /** Kill task.
  303.  *
  304.  * @param id ID of the task to be killed.
  305.  *
  306.  * @return 0 on success or an error code from errno.h
  307.  */
  308. int task_kill(task_id_t id)
  309. {
  310.     ipl_t ipl;
  311.     task_t *ta;
  312.     thread_t *t;
  313.     link_t *cur;
  314.  
  315.     if (id == 1)
  316.         return EPERM;
  317.    
  318.     ipl = interrupts_disable();
  319.     spinlock_lock(&tasks_lock);
  320.  
  321.     if (!(ta = task_find_by_id(id))) {
  322.         spinlock_unlock(&tasks_lock);
  323.         interrupts_restore(ipl);
  324.         return ENOENT;
  325.     }
  326.  
  327.     spinlock_lock(&ta->lock);
  328.     ta->refcount++;
  329.     spinlock_unlock(&ta->lock);
  330.  
  331.     btree_remove(&tasks_btree, ta->taskid, NULL);
  332.     spinlock_unlock(&tasks_lock);
  333.    
  334.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp", true);
  335.    
  336.     spinlock_lock(&ta->lock);
  337.     ta->accept_new_threads = false;
  338.     ta->refcount--;
  339.  
  340.     /*
  341.      * Interrupt all threads except ktaskclnp.
  342.      */
  343.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  344.         thread_t *thr;
  345.         bool  sleeping = false;
  346.        
  347.         thr = list_get_instance(cur, thread_t, th_link);
  348.         if (thr == t)
  349.             continue;
  350.            
  351.         spinlock_lock(&thr->lock);
  352.         thr->interrupted = true;
  353.         if (thr->state == Sleeping)
  354.             sleeping = true;
  355.         spinlock_unlock(&thr->lock);
  356.        
  357.         if (sleeping)
  358.             waitq_interrupt_sleep(thr);
  359.     }
  360.    
  361.     spinlock_unlock(&ta->lock);
  362.     interrupts_restore(ipl);
  363.    
  364.     if (t)
  365.         thread_ready(t);
  366.  
  367.     return 0;
  368. }
  369.  
  370. /** Print task list */
  371. void task_print_list(void)
  372. {
  373.     link_t *cur;
  374.     ipl_t ipl;
  375.    
  376.     /* Messing with thread structures, avoid deadlock */
  377.     ipl = interrupts_disable();
  378.     spinlock_lock(&tasks_lock);
  379.    
  380.     printf("taskid name       ctx address    as         cycles     threads "
  381.         "calls  callee\n");
  382.     printf("------ ---------- --- ---------- ---------- ---------- ------- "        "------ ------>\n");
  383.  
  384.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head;
  385.         cur = cur->next) {
  386.         btree_node_t *node;
  387.         unsigned int i;
  388.        
  389.         node = list_get_instance(cur, btree_node_t, leaf_link);
  390.         for (i = 0; i < node->keys; i++) {
  391.             task_t *t;
  392.             int j;
  393.  
  394.             t = (task_t *) node->value[i];
  395.        
  396.             spinlock_lock(&t->lock);
  397.            
  398.             uint64_t cycles;
  399.             char suffix;
  400.             order(task_get_accounting(t), &cycles, &suffix);
  401.            
  402.             printf("%-6lld %-10s %-3ld %#10zx %#10zx %9llu%c %7zd "
  403.                 "%6zd", t->taskid, t->name, t->context, t, t->as,
  404.                 cycles, suffix, t->refcount,
  405.                 atomic_get(&t->active_calls));
  406.             for (j = 0; j < IPC_MAX_PHONES; j++) {
  407.                 if (t->phones[j].callee)
  408.                     printf(" %zd:%#zx", j,
  409.                         t->phones[j].callee);
  410.             }
  411.             printf("\n");
  412.            
  413.             spinlock_unlock(&t->lock);
  414.         }
  415.     }
  416.  
  417.     spinlock_unlock(&tasks_lock);
  418.     interrupts_restore(ipl);
  419. }
  420.  
  421. /** Kernel thread used to cleanup the task after it is killed. */
  422. void ktaskclnp(void *arg)
  423. {
  424.     ipl_t ipl;
  425.     thread_t *t = NULL, *main_thread;
  426.     link_t *cur;
  427.     bool again;
  428.  
  429.     thread_detach(THREAD);
  430.  
  431. loop:
  432.     ipl = interrupts_disable();
  433.     spinlock_lock(&TASK->lock);
  434.    
  435.     main_thread = TASK->main_thread;
  436.    
  437.     /*
  438.      * Find a thread to join.
  439.      */
  440.     again = false;
  441.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  442.         t = list_get_instance(cur, thread_t, th_link);
  443.  
  444.         spinlock_lock(&t->lock);
  445.         if (t == THREAD) {
  446.             spinlock_unlock(&t->lock);
  447.             continue;
  448.         } else if (t == main_thread) {
  449.             spinlock_unlock(&t->lock);
  450.             continue;
  451.         } else if (t->join_type != None) {
  452.             spinlock_unlock(&t->lock);
  453.             again = true;
  454.             continue;
  455.         } else {
  456.             t->join_type = TaskClnp;
  457.             spinlock_unlock(&t->lock);
  458.             again = false;
  459.             break;
  460.         }
  461.     }
  462.    
  463.     spinlock_unlock(&TASK->lock);
  464.     interrupts_restore(ipl);
  465.    
  466.     if (again) {
  467.         /*
  468.          * Other cleanup (e.g. ktaskgc) is in progress.
  469.          */
  470.         scheduler();
  471.         goto loop;
  472.     }
  473.    
  474.     if (t != THREAD) {
  475.         ASSERT(t != main_thread);   /* uninit is joined and detached
  476.                          * in ktaskgc */
  477.         thread_join(t);
  478.         thread_detach(t);
  479.         goto loop;          /* go for another thread */
  480.     }
  481.    
  482.     /*
  483.      * Now there are no other threads in this task
  484.      * and no new threads can be created.
  485.      */
  486.  
  487.     ipc_cleanup();
  488.     futex_cleanup();
  489.     klog_printf("Cleanup of task %lld completed.", TASK->taskid);
  490. }
  491.  
  492. /** Kernel thread used to kill the userspace task when its main thread exits.
  493.  *
  494.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  495.  * When this happens, the task is killed. In the meantime, exited threads
  496.  * are garbage collected.
  497.  *
  498.  * @param arg Pointer to the thread structure of the task's main thread.
  499.  */
  500. void ktaskgc(void *arg)
  501. {
  502.     thread_t *t = (thread_t *) arg;
  503. loop:  
  504.     /*
  505.      * Userspace threads cannot detach themselves,
  506.      * therefore the thread pointer is guaranteed to be valid.
  507.      */
  508.     if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) ==
  509.         ESYNCH_TIMEOUT) {   /* sleep uninterruptibly here! */
  510.         ipl_t ipl;
  511.         link_t *cur;
  512.         thread_t *thr = NULL;
  513.    
  514.         /*
  515.          * The join timed out. Try to do some garbage collection of
  516.          * 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;
  523.             cur = cur->next) {
  524.             thr = list_get_instance(cur, thread_t, th_link);
  525.             spinlock_lock(&thr->lock);
  526.             if (thr != t && thr->state == Undead &&
  527.                 thr->join_type == None) {
  528.                 thr->join_type = TaskGC;
  529.                 spinlock_unlock(&thr->lock);
  530.                 break;
  531.             }
  532.             spinlock_unlock(&thr->lock);
  533.             thr = NULL;
  534.         }
  535.         spinlock_unlock(&TASK->lock);
  536.         interrupts_restore(ipl);
  537.        
  538.         if (thr) {
  539.             thread_join(thr);
  540.             thread_detach(thr);
  541.             scheduler();
  542.             goto more_gc;
  543.         }
  544.            
  545.         goto loop;
  546.     }
  547.     thread_detach(t);
  548.     task_kill(TASK->taskid);
  549. }
  550.  
  551. /** @}
  552.  */
  553.