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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 <synch/waitq.h>
  46. #include <arch.h>
  47. #include <panic.h>
  48. #include <adt/btree.h>
  49. #include <adt/list.h>
  50. #include <ipc/ipc.h>
  51. #include <security/cap.h>
  52. #include <memstr.h>
  53. #include <print.h>
  54. #include <lib/elf.h>
  55. #include <errno.h>
  56. #include <func.h>
  57. #include <syscall/copy.h>
  58. #include <console/klog.h>
  59.  
  60. #ifndef LOADED_PROG_STACK_PAGES_NO
  61. #define LOADED_PROG_STACK_PAGES_NO 1
  62. #endif
  63.  
  64. /** Spinlock protecting the tasks_btree B+tree. */
  65. SPINLOCK_INITIALIZE(tasks_lock);
  66.  
  67. /** B+tree of active tasks.
  68.  *
  69.  * The task is guaranteed to exist after it was found in the tasks_btree as
  70.  * long as:
  71.  * @li the tasks_lock is held,
  72.  * @li the task's lock is held when task's lock is acquired before releasing
  73.  *     tasks_lock or
  74.  * @li the task's refcount is greater than 0
  75.  *
  76.  */
  77. btree_t tasks_btree;
  78.  
  79. static task_id_t task_counter = 0;
  80.  
  81. static void ktaskclnp(void *arg);
  82. static void ktaskgc(void *arg);
  83.  
  84. /** Initialize tasks
  85.  *
  86.  * Initialize kernel tasks support.
  87.  *
  88.  */
  89. void task_init(void)
  90. {
  91.     TASK = NULL;
  92.     btree_create(&tasks_btree);
  93. }
  94.  
  95.  
  96. /** Create new task
  97.  *
  98.  * Create new task with no threads.
  99.  *
  100.  * @param as Task's address space.
  101.  * @param name Symbolic name.
  102.  *
  103.  * @return New task's structure
  104.  *
  105.  */
  106. task_t *task_create(as_t *as, char *name)
  107. {
  108.     ipl_t ipl;
  109.     task_t *ta;
  110.     int i;
  111.    
  112.     ta = (task_t *) malloc(sizeof(task_t), 0);
  113.  
  114.     task_create_arch(ta);
  115.  
  116.     spinlock_initialize(&ta->lock, "task_ta_lock");
  117.     list_initialize(&ta->th_head);
  118.     ta->as = as;
  119.     ta->name = name;
  120.     ta->main_thread = NULL;
  121.     ta->refcount = 0;
  122.     ta->context = CONTEXT;
  123.  
  124.     ta->capabilities = 0;
  125.     ta->accept_new_threads = true;
  126.     ta->cycles = 0;
  127.    
  128.     ipc_answerbox_init(&ta->answerbox);
  129.     for (i = 0; i < IPC_MAX_PHONES; i++)
  130.         ipc_phone_init(&ta->phones[i]);
  131.     if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context,
  132.         ta->context)))
  133.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  134.     atomic_set(&ta->active_calls, 0);
  135.  
  136.     mutex_initialize(&ta->futexes_lock);
  137.     btree_create(&ta->futexes);
  138.    
  139.     ipl = interrupts_disable();
  140.  
  141.     /*
  142.      * Increment address space reference count.
  143.      * TODO: Reconsider the locking scheme.
  144.      */
  145.     mutex_lock(&as->lock);
  146.     as->refcount++;
  147.     mutex_unlock(&as->lock);
  148.  
  149.     spinlock_lock(&tasks_lock);
  150.  
  151.     ta->taskid = ++task_counter;
  152.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  153.  
  154.     spinlock_unlock(&tasks_lock);
  155.     interrupts_restore(ipl);
  156.  
  157.     return ta;
  158. }
  159.  
  160. /** Destroy task.
  161.  *
  162.  * @param t Task to be destroyed.
  163.  */
  164. void task_destroy(task_t *t)
  165. {
  166.     task_destroy_arch(t);
  167.     btree_destroy(&t->futexes);
  168.  
  169.     mutex_lock_active(&t->as->lock);
  170.     if (--t->as->refcount == 0) {
  171.         mutex_unlock(&t->as->lock);
  172.         as_destroy(t->as);
  173.         /*
  174.          * t->as is destroyed.
  175.          */
  176.     } else
  177.         mutex_unlock(&t->as->lock);
  178.    
  179.     free(t);
  180.     TASK = NULL;
  181. }
  182.  
  183. /** Create new task with 1 thread and run it
  184.  *
  185.  * @param program_addr Address of program executable image.
  186.  * @param name Program name.
  187.  *
  188.  * @return Task of the running program or NULL on error.
  189.  */
  190. task_t * task_run_program(void *program_addr, char *name)
  191. {
  192.     as_t *as;
  193.     as_area_t *a;
  194.     int rc;
  195.     thread_t *t1, *t2;
  196.     task_t *task;
  197.     uspace_arg_t *kernel_uarg;
  198.  
  199.     as = as_create(0);
  200.     ASSERT(as);
  201.  
  202.     rc = elf_load((elf_header_t *) program_addr, as);
  203.     if (rc != EE_OK) {
  204.         as_destroy(as);
  205.         return NULL;
  206.     }
  207.    
  208.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  209.     kernel_uarg->uspace_entry =
  210.         (void *) ((elf_header_t *) program_addr)->e_entry;
  211.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  212.     kernel_uarg->uspace_thread_function = NULL;
  213.     kernel_uarg->uspace_thread_arg = NULL;
  214.     kernel_uarg->uspace_uarg = NULL;
  215.    
  216.     task = task_create(as, name);
  217.     ASSERT(task);
  218.  
  219.     /*
  220.      * Create the data as_area.
  221.      */
  222.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  223.         LOADED_PROG_STACK_PAGES_NO * PAGE_SIZE, USTACK_ADDRESS,
  224.         AS_AREA_ATTR_NONE, &anon_backend, NULL);
  225.  
  226.     /*
  227.      * Create the main thread.
  228.      */
  229.     t1 = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
  230.         "uinit", false);
  231.     ASSERT(t1);
  232.    
  233.     /*
  234.      * Create killer thread for the new task.
  235.      */
  236.     t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc", true);
  237.     ASSERT(t2);
  238.     thread_ready(t2);
  239.  
  240.     thread_ready(t1);
  241.  
  242.     return task;
  243. }
  244.  
  245. /** Syscall for reading task ID from userspace.
  246.  *
  247.  * @param uspace_task_id Userspace address of 8-byte buffer where to store
  248.  * current task ID.
  249.  *
  250.  * @return 0 on success or an error code from @ref errno.h.
  251.  */
  252. unative_t sys_task_get_id(task_id_t *uspace_task_id)
  253. {
  254.     /*
  255.      * No need to acquire lock on TASK because taskid
  256.      * remains constant for the lifespan of the task.
  257.      */
  258.     return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid,
  259.         sizeof(TASK->taskid));
  260. }
  261.  
  262. /** Find task structure corresponding to task ID.
  263.  *
  264.  * The tasks_lock must be already held by the caller of this function
  265.  * and interrupts must be disabled.
  266.  *
  267.  * @param id Task ID.
  268.  *
  269.  * @return Task structure address or NULL if there is no such task ID.
  270.  */
  271. task_t *task_find_by_id(task_id_t id)
  272. {
  273.     btree_node_t *leaf;
  274.    
  275.     return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
  276. }
  277.  
  278. /** Get accounting data of given task.
  279.  *
  280.  * Note that task lock of 't' must be already held and
  281.  * interrupts must be already disabled.
  282.  *
  283.  * @param t Pointer to thread.
  284.  *
  285.  */
  286. uint64_t task_get_accounting(task_t *t)
  287. {
  288.     /* Accumulated value of task */
  289.     uint64_t ret = t->cycles;
  290.    
  291.     /* Current values of threads */
  292.     link_t *cur;
  293.     for (cur = t->th_head.next; cur != &t->th_head; cur = cur->next) {
  294.         thread_t *thr = list_get_instance(cur, thread_t, th_link);
  295.        
  296.         spinlock_lock(&thr->lock);
  297.         /* Process only counted threads */
  298.         if (!thr->uncounted) {
  299.             if (thr == THREAD) {
  300.                 /* Update accounting of current thread */
  301.                 thread_update_accounting();
  302.             }
  303.             ret += thr->cycles;
  304.         }
  305.         spinlock_unlock(&thr->lock);
  306.     }
  307.    
  308.     return ret;
  309. }
  310.  
  311. /** Kill task.
  312.  *
  313.  * @param id ID of the task to be killed.
  314.  *
  315.  * @return 0 on success or an error code from errno.h
  316.  */
  317. int task_kill(task_id_t id)
  318. {
  319.     ipl_t ipl;
  320.     task_t *ta;
  321.     thread_t *t;
  322.     link_t *cur;
  323.  
  324.     if (id == 1)
  325.         return EPERM;
  326.    
  327.     ipl = interrupts_disable();
  328.     spinlock_lock(&tasks_lock);
  329.  
  330.     if (!(ta = task_find_by_id(id))) {
  331.         spinlock_unlock(&tasks_lock);
  332.         interrupts_restore(ipl);
  333.         return ENOENT;
  334.     }
  335.  
  336.     spinlock_lock(&ta->lock);
  337.     ta->refcount++;
  338.     spinlock_unlock(&ta->lock);
  339.  
  340.     btree_remove(&tasks_btree, ta->taskid, NULL);
  341.     spinlock_unlock(&tasks_lock);
  342.    
  343.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp", true);
  344.    
  345.     spinlock_lock(&ta->lock);
  346.     ta->accept_new_threads = false;
  347.     ta->refcount--;
  348.  
  349.     /*
  350.      * Interrupt all threads except ktaskclnp.
  351.      */
  352.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  353.         thread_t *thr;
  354.         bool  sleeping = false;
  355.        
  356.         thr = list_get_instance(cur, thread_t, th_link);
  357.         if (thr == t)
  358.             continue;
  359.            
  360.         spinlock_lock(&thr->lock);
  361.         thr->interrupted = true;
  362.         if (thr->state == Sleeping)
  363.             sleeping = true;
  364.         spinlock_unlock(&thr->lock);
  365.        
  366.         if (sleeping)
  367.             waitq_interrupt_sleep(thr);
  368.     }
  369.    
  370.     spinlock_unlock(&ta->lock);
  371.     interrupts_restore(ipl);
  372.    
  373.     if (t)
  374.         thread_ready(t);
  375.  
  376.     return 0;
  377. }
  378.  
  379. /** Print task list */
  380. void task_print_list(void)
  381. {
  382.     link_t *cur;
  383.     ipl_t ipl;
  384.    
  385.     /* Messing with thread structures, avoid deadlock */
  386.     ipl = interrupts_disable();
  387.     spinlock_lock(&tasks_lock);
  388.    
  389.     printf("taskid name       ctx address    as         cycles     threads "
  390.         "calls  callee\n");
  391.     printf("------ ---------- --- ---------- ---------- ---------- ------- "        "------ ------>\n");
  392.  
  393.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head;
  394.         cur = cur->next) {
  395.         btree_node_t *node;
  396.         int i;
  397.        
  398.         node = list_get_instance(cur, btree_node_t, leaf_link);
  399.         for (i = 0; i < node->keys; i++) {
  400.             task_t *t;
  401.             int j;
  402.  
  403.             t = (task_t *) node->value[i];
  404.        
  405.             spinlock_lock(&t->lock);
  406.            
  407.             uint64_t cycles;
  408.             char suffix;
  409.             order(task_get_accounting(t), &cycles, &suffix);
  410.            
  411.             printf("%-6lld %-10s %-3ld %#10zx %#10zx %9llu%c %7zd "
  412.                 "%6zd", t->taskid, t->name, t->context, t, t->as,
  413.                 cycles, suffix, t->refcount,
  414.                 atomic_get(&t->active_calls));
  415.             for (j = 0; j < IPC_MAX_PHONES; j++) {
  416.                 if (t->phones[j].callee)
  417.                     printf(" %zd:%#zx", j,
  418.                         t->phones[j].callee);
  419.             }
  420.             printf("\n");
  421.            
  422.             spinlock_unlock(&t->lock);
  423.         }
  424.     }
  425.  
  426.     spinlock_unlock(&tasks_lock);
  427.     interrupts_restore(ipl);
  428. }
  429.  
  430. /** Kernel thread used to cleanup the task after it is killed. */
  431. void ktaskclnp(void *arg)
  432. {
  433.     ipl_t ipl;
  434.     thread_t *t = NULL, *main_thread;
  435.     link_t *cur;
  436.     bool again;
  437.  
  438.     thread_detach(THREAD);
  439.  
  440. loop:
  441.     ipl = interrupts_disable();
  442.     spinlock_lock(&TASK->lock);
  443.    
  444.     main_thread = TASK->main_thread;
  445.    
  446.     /*
  447.      * Find a thread to join.
  448.      */
  449.     again = false;
  450.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  451.         t = list_get_instance(cur, thread_t, th_link);
  452.  
  453.         spinlock_lock(&t->lock);
  454.         if (t == THREAD) {
  455.             spinlock_unlock(&t->lock);
  456.             continue;
  457.         } else if (t == main_thread) {
  458.             spinlock_unlock(&t->lock);
  459.             continue;
  460.         } else if (t->join_type != None) {
  461.             spinlock_unlock(&t->lock);
  462.             again = true;
  463.             continue;
  464.         } else {
  465.             t->join_type = TaskClnp;
  466.             spinlock_unlock(&t->lock);
  467.             again = false;
  468.             break;
  469.         }
  470.     }
  471.    
  472.     spinlock_unlock(&TASK->lock);
  473.     interrupts_restore(ipl);
  474.    
  475.     if (again) {
  476.         /*
  477.          * Other cleanup (e.g. ktaskgc) is in progress.
  478.          */
  479.         scheduler();
  480.         goto loop;
  481.     }
  482.    
  483.     if (t != THREAD) {
  484.         ASSERT(t != main_thread);   /* uninit is joined and detached
  485.                          * in ktaskgc */
  486.         thread_join(t);
  487.         thread_detach(t);
  488.         goto loop;          /* go for another thread */
  489.     }
  490.    
  491.     /*
  492.      * Now there are no other threads in this task
  493.      * and no new threads can be created.
  494.      */
  495.  
  496.     ipc_cleanup();
  497.     futex_cleanup();
  498.     klog_printf("Cleanup of task %lld completed.", TASK->taskid);
  499. }
  500.  
  501. /** Kernel thread used to kill the userspace task when its main thread exits.
  502.  *
  503.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  504.  * When this happens, the task is killed. In the meantime, exited threads
  505.  * are garbage collected.
  506.  *
  507.  * @param arg Pointer to the thread structure of the task's main thread.
  508.  */
  509. void ktaskgc(void *arg)
  510. {
  511.     thread_t *t = (thread_t *) arg;
  512. loop:  
  513.     /*
  514.      * Userspace threads cannot detach themselves,
  515.      * therefore the thread pointer is guaranteed to be valid.
  516.      */
  517.     if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) ==
  518.         ESYNCH_TIMEOUT) {   /* sleep uninterruptibly here! */
  519.         ipl_t ipl;
  520.         link_t *cur;
  521.         thread_t *thr = NULL;
  522.    
  523.         /*
  524.          * The join timed out. Try to do some garbage collection of
  525.          * Undead threads.
  526.          */
  527. more_gc:       
  528.         ipl = interrupts_disable();
  529.         spinlock_lock(&TASK->lock);
  530.        
  531.         for (cur = TASK->th_head.next; cur != &TASK->th_head;
  532.             cur = cur->next) {
  533.             thr = list_get_instance(cur, thread_t, th_link);
  534.             spinlock_lock(&thr->lock);
  535.             if (thr != t && thr->state == Undead &&
  536.                 thr->join_type == None) {
  537.                 thr->join_type = TaskGC;
  538.                 spinlock_unlock(&thr->lock);
  539.                 break;
  540.             }
  541.             spinlock_unlock(&thr->lock);
  542.             thr = NULL;
  543.         }
  544.         spinlock_unlock(&TASK->lock);
  545.         interrupts_restore(ipl);
  546.        
  547.         if (thr) {
  548.             thread_join(thr);
  549.             thread_detach(thr);
  550.             scheduler();
  551.             goto more_gc;
  552.         }
  553.            
  554.         goto loop;
  555.     }
  556.     thread_detach(t);
  557.     task_kill(TASK->taskid);
  558. }
  559.  
  560. /** @}
  561.  */
  562.