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