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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. /** Kill all tasks except the current task.
  97.  *
  98.  */
  99. void task_done(void)
  100. {
  101.     task_t *t;
  102.     do { /* Repeat until there are any tasks except TASK */
  103.        
  104.         /* Messing with task structures, avoid deadlock */
  105.         ipl_t ipl = interrupts_disable();
  106.         spinlock_lock(&tasks_lock);
  107.        
  108.         t = NULL;
  109.         link_t *cur;
  110.         for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head; cur = cur->next) {
  111.             btree_node_t *node = list_get_instance(cur, btree_node_t, leaf_link);
  112.            
  113.             unsigned int i;
  114.             for (i = 0; i < node->keys; i++) {
  115.                 if ((task_t *) node->value[i] != TASK) {
  116.                     t = (task_t *) node->value[i];
  117.                     break;
  118.                 }
  119.             }
  120.         }
  121.        
  122.         if (t != NULL) {
  123.             task_id_t id = t->taskid;
  124.            
  125.             spinlock_unlock(&tasks_lock);
  126.             interrupts_restore(ipl);
  127.            
  128. #ifdef CONFIG_DEBUG
  129.             printf("Killing task %llu\n", id);
  130. #endif         
  131.             task_kill(id);
  132.         } else {
  133.             spinlock_unlock(&tasks_lock);
  134.             interrupts_restore(ipl);
  135.         }
  136.        
  137.     } while (t != NULL);
  138. }
  139.  
  140. /** Create new task
  141.  *
  142.  * Create new task with no threads.
  143.  *
  144.  * @param as Task's address space.
  145.  * @param name Symbolic name.
  146.  *
  147.  * @return New task's structure
  148.  *
  149.  */
  150. task_t *task_create(as_t *as, char *name)
  151. {
  152.     ipl_t ipl;
  153.     task_t *ta;
  154.     int i;
  155.    
  156.     ta = (task_t *) malloc(sizeof(task_t), 0);
  157.  
  158.     task_create_arch(ta);
  159.  
  160.     spinlock_initialize(&ta->lock, "task_ta_lock");
  161.     list_initialize(&ta->th_head);
  162.     ta->as = as;
  163.     ta->name = name;
  164.     ta->main_thread = NULL;
  165.     ta->refcount = 0;
  166.     ta->context = CONTEXT;
  167.  
  168.     ta->capabilities = 0;
  169.     ta->accept_new_threads = true;
  170.     ta->cycles = 0;
  171.    
  172.     ipc_answerbox_init(&ta->answerbox);
  173.     for (i = 0; i < IPC_MAX_PHONES; i++)
  174.         ipc_phone_init(&ta->phones[i]);
  175.     if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context,
  176.         ta->context)))
  177.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  178.     atomic_set(&ta->active_calls, 0);
  179.  
  180.     mutex_initialize(&ta->futexes_lock);
  181.     btree_create(&ta->futexes);
  182.    
  183.     ipl = interrupts_disable();
  184.  
  185.     /*
  186.      * Increment address space reference count.
  187.      */
  188.     atomic_inc(&as->refcount);
  189.  
  190.     spinlock_lock(&tasks_lock);
  191.  
  192.     ta->taskid = ++task_counter;
  193.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  194.  
  195.     spinlock_unlock(&tasks_lock);
  196.     interrupts_restore(ipl);
  197.  
  198.     return ta;
  199. }
  200.  
  201. /** Destroy task.
  202.  *
  203.  * @param t Task to be destroyed.
  204.  */
  205. void task_destroy(task_t *t)
  206. {
  207.     task_destroy_arch(t);
  208.     btree_destroy(&t->futexes);
  209.  
  210.     if (atomic_predec(&t->as->refcount) == 0)
  211.         as_destroy(t->as);
  212.    
  213.     free(t);
  214.     TASK = NULL;
  215. }
  216.  
  217. /** Create new task with 1 thread and run it
  218.  *
  219.  * @param program_addr Address of program executable image.
  220.  * @param name Program name.
  221.  *
  222.  * @return Task of the running program or NULL on error.
  223.  */
  224. task_t * task_run_program(void *program_addr, char *name)
  225. {
  226.     as_t *as;
  227.     as_area_t *a;
  228.     int rc;
  229.     thread_t *t1, *t2;
  230.     task_t *task;
  231.     uspace_arg_t *kernel_uarg;
  232.  
  233.     as = as_create(0);
  234.     ASSERT(as);
  235.  
  236.     rc = elf_load((elf_header_t *) program_addr, as);
  237.     if (rc != EE_OK) {
  238.         as_destroy(as);
  239.         return NULL;
  240.     }
  241.    
  242.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  243.     kernel_uarg->uspace_entry =
  244.         (void *) ((elf_header_t *) program_addr)->e_entry;
  245.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  246.     kernel_uarg->uspace_thread_function = NULL;
  247.     kernel_uarg->uspace_thread_arg = NULL;
  248.     kernel_uarg->uspace_uarg = NULL;
  249.    
  250.     task = task_create(as, name);
  251.     ASSERT(task);
  252.  
  253.     /*
  254.      * Create the data as_area.
  255.      */
  256.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  257.         LOADED_PROG_STACK_PAGES_NO * PAGE_SIZE, USTACK_ADDRESS,
  258.         AS_AREA_ATTR_NONE, &anon_backend, NULL);
  259.  
  260.     /*
  261.      * Create the main thread.
  262.      */
  263.     t1 = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
  264.         "uinit", false);
  265.     ASSERT(t1);
  266.    
  267.     /*
  268.      * Create killer thread for the new task.
  269.      */
  270.     t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc", true);
  271.     ASSERT(t2);
  272.     thread_ready(t2);
  273.  
  274.     thread_ready(t1);
  275.  
  276.     return task;
  277. }
  278.  
  279. /** Syscall for reading task ID from userspace.
  280.  *
  281.  * @param uspace_task_id Userspace address of 8-byte buffer where to store
  282.  * current task ID.
  283.  *
  284.  * @return 0 on success or an error code from @ref errno.h.
  285.  */
  286. unative_t sys_task_get_id(task_id_t *uspace_task_id)
  287. {
  288.     /*
  289.      * No need to acquire lock on TASK because taskid
  290.      * remains constant for the lifespan of the task.
  291.      */
  292.     return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid,
  293.         sizeof(TASK->taskid));
  294. }
  295.  
  296. /** Find task structure corresponding to task ID.
  297.  *
  298.  * The tasks_lock must be already held by the caller of this function
  299.  * and interrupts must be disabled.
  300.  *
  301.  * @param id Task ID.
  302.  *
  303.  * @return Task structure address or NULL if there is no such task ID.
  304.  */
  305. task_t *task_find_by_id(task_id_t id)
  306. {
  307.     btree_node_t *leaf;
  308.    
  309.     return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
  310. }
  311.  
  312. /** Get accounting data of given task.
  313.  *
  314.  * Note that task lock of 't' must be already held and
  315.  * interrupts must be already disabled.
  316.  *
  317.  * @param t Pointer to thread.
  318.  *
  319.  */
  320. uint64_t task_get_accounting(task_t *t)
  321. {
  322.     /* Accumulated value of task */
  323.     uint64_t ret = t->cycles;
  324.    
  325.     /* Current values of threads */
  326.     link_t *cur;
  327.     for (cur = t->th_head.next; cur != &t->th_head; cur = cur->next) {
  328.         thread_t *thr = list_get_instance(cur, thread_t, th_link);
  329.        
  330.         spinlock_lock(&thr->lock);
  331.         /* Process only counted threads */
  332.         if (!thr->uncounted) {
  333.             if (thr == THREAD) {
  334.                 /* Update accounting of current thread */
  335.                 thread_update_accounting();
  336.             }
  337.             ret += thr->cycles;
  338.         }
  339.         spinlock_unlock(&thr->lock);
  340.     }
  341.    
  342.     return ret;
  343. }
  344.  
  345. /** Kill task.
  346.  *
  347.  * @param id ID of the task to be killed.
  348.  *
  349.  * @return 0 on success or an error code from errno.h
  350.  */
  351. int task_kill(task_id_t id)
  352. {
  353.     ipl_t ipl;
  354.     task_t *ta;
  355.     thread_t *t;
  356.     link_t *cur;
  357.  
  358.     if (id == 1)
  359.         return EPERM;
  360.    
  361.     ipl = interrupts_disable();
  362.     spinlock_lock(&tasks_lock);
  363.  
  364.     if (!(ta = task_find_by_id(id))) {
  365.         spinlock_unlock(&tasks_lock);
  366.         interrupts_restore(ipl);
  367.         return ENOENT;
  368.     }
  369.  
  370.     spinlock_lock(&ta->lock);
  371.     ta->refcount++;
  372.     spinlock_unlock(&ta->lock);
  373.  
  374.     btree_remove(&tasks_btree, ta->taskid, NULL);
  375.     spinlock_unlock(&tasks_lock);
  376.    
  377.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp", true);
  378.    
  379.     spinlock_lock(&ta->lock);
  380.     ta->accept_new_threads = false;
  381.     ta->refcount--;
  382.  
  383.     /*
  384.      * Interrupt all threads except ktaskclnp.
  385.      */
  386.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  387.         thread_t *thr;
  388.         bool  sleeping = false;
  389.        
  390.         thr = list_get_instance(cur, thread_t, th_link);
  391.         if (thr == t)
  392.             continue;
  393.            
  394.         spinlock_lock(&thr->lock);
  395.         thr->interrupted = true;
  396.         if (thr->state == Sleeping)
  397.             sleeping = true;
  398.         spinlock_unlock(&thr->lock);
  399.        
  400.         if (sleeping)
  401.             waitq_interrupt_sleep(thr);
  402.     }
  403.    
  404.     spinlock_unlock(&ta->lock);
  405.     interrupts_restore(ipl);
  406.    
  407.     if (t)
  408.         thread_ready(t);
  409.  
  410.     return 0;
  411. }
  412.  
  413. /** Print task list */
  414. void task_print_list(void)
  415. {
  416.     link_t *cur;
  417.     ipl_t ipl;
  418.    
  419.     /* Messing with task structures, avoid deadlock */
  420.     ipl = interrupts_disable();
  421.     spinlock_lock(&tasks_lock);
  422.    
  423.     printf("taskid name       ctx address    as         cycles     threads "
  424.         "calls  callee\n");
  425.     printf("------ ---------- --- ---------- ---------- ---------- ------- "        "------ ------>\n");
  426.  
  427.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head;
  428.         cur = cur->next) {
  429.         btree_node_t *node;
  430.         unsigned int i;
  431.        
  432.         node = list_get_instance(cur, btree_node_t, leaf_link);
  433.         for (i = 0; i < node->keys; i++) {
  434.             task_t *t;
  435.             int j;
  436.  
  437.             t = (task_t *) node->value[i];
  438.        
  439.             spinlock_lock(&t->lock);
  440.            
  441.             uint64_t cycles;
  442.             char suffix;
  443.             order(task_get_accounting(t), &cycles, &suffix);
  444.            
  445.             printf("%-6llu %-10s %-3ld %#10zx %#10zx %9llu%c %7zd "
  446.                 "%6zd", t->taskid, t->name, t->context, t, t->as,
  447.                 cycles, suffix, t->refcount,
  448.                 atomic_get(&t->active_calls));
  449.             for (j = 0; j < IPC_MAX_PHONES; j++) {
  450.                 if (t->phones[j].callee)
  451.                     printf(" %zd:%#zx", j,
  452.                         t->phones[j].callee);
  453.             }
  454.             printf("\n");
  455.            
  456.             spinlock_unlock(&t->lock);
  457.         }
  458.     }
  459.  
  460.     spinlock_unlock(&tasks_lock);
  461.     interrupts_restore(ipl);
  462. }
  463.  
  464. /** Kernel thread used to cleanup the task after it is killed. */
  465. void ktaskclnp(void *arg)
  466. {
  467.     ipl_t ipl;
  468.     thread_t *t = NULL, *main_thread;
  469.     link_t *cur;
  470.     bool again;
  471.  
  472.     thread_detach(THREAD);
  473.  
  474. loop:
  475.     ipl = interrupts_disable();
  476.     spinlock_lock(&TASK->lock);
  477.    
  478.     main_thread = TASK->main_thread;
  479.    
  480.     /*
  481.      * Find a thread to join.
  482.      */
  483.     again = false;
  484.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  485.         t = list_get_instance(cur, thread_t, th_link);
  486.  
  487.         spinlock_lock(&t->lock);
  488.         if (t == THREAD) {
  489.             spinlock_unlock(&t->lock);
  490.             continue;
  491.         } else if (t == main_thread) {
  492.             spinlock_unlock(&t->lock);
  493.             continue;
  494.         } else if (t->join_type != None) {
  495.             spinlock_unlock(&t->lock);
  496.             again = true;
  497.             continue;
  498.         } else {
  499.             t->join_type = TaskClnp;
  500.             spinlock_unlock(&t->lock);
  501.             again = false;
  502.             break;
  503.         }
  504.     }
  505.    
  506.     spinlock_unlock(&TASK->lock);
  507.     interrupts_restore(ipl);
  508.    
  509.     if (again) {
  510.         /*
  511.          * Other cleanup (e.g. ktaskgc) is in progress.
  512.          */
  513.         scheduler();
  514.         goto loop;
  515.     }
  516.    
  517.     if (t != THREAD) {
  518.         ASSERT(t != main_thread);   /* uninit is joined and detached
  519.                          * in ktaskgc */
  520.         thread_join(t);
  521.         thread_detach(t);
  522.         goto loop;          /* go for another thread */
  523.     }
  524.    
  525.     /*
  526.      * Now there are no other threads in this task
  527.      * and no new threads can be created.
  528.      */
  529.  
  530.     ipc_cleanup();
  531.     futex_cleanup();
  532.     klog_printf("Cleanup of task %llu completed.", TASK->taskid);
  533. }
  534.  
  535. /** Kernel thread used to kill the userspace task when its main thread exits.
  536.  *
  537.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  538.  * When this happens, the task is killed. In the meantime, exited threads
  539.  * are garbage collected.
  540.  *
  541.  * @param arg Pointer to the thread structure of the task's main thread.
  542.  */
  543. void ktaskgc(void *arg)
  544. {
  545.     thread_t *t = (thread_t *) arg;
  546. loop:  
  547.     /*
  548.      * Userspace threads cannot detach themselves,
  549.      * therefore the thread pointer is guaranteed to be valid.
  550.      */
  551.     if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) ==
  552.         ESYNCH_TIMEOUT) {   /* sleep uninterruptibly here! */
  553.         ipl_t ipl;
  554.         link_t *cur;
  555.         thread_t *thr = NULL;
  556.    
  557.         /*
  558.          * The join timed out. Try to do some garbage collection of
  559.          * Undead threads.
  560.          */
  561. more_gc:       
  562.         ipl = interrupts_disable();
  563.         spinlock_lock(&TASK->lock);
  564.        
  565.         for (cur = TASK->th_head.next; cur != &TASK->th_head;
  566.             cur = cur->next) {
  567.             thr = list_get_instance(cur, thread_t, th_link);
  568.             spinlock_lock(&thr->lock);
  569.             if (thr != t && thr->state == Undead &&
  570.                 thr->join_type == None) {
  571.                 thr->join_type = TaskGC;
  572.                 spinlock_unlock(&thr->lock);
  573.                 break;
  574.             }
  575.             spinlock_unlock(&thr->lock);
  576.             thr = NULL;
  577.         }
  578.         spinlock_unlock(&TASK->lock);
  579.         interrupts_restore(ipl);
  580.        
  581.         if (thr) {
  582.             thread_join(thr);
  583.             thread_detach(thr);
  584.             scheduler();
  585.             goto more_gc;
  586.         }
  587.            
  588.         goto loop;
  589.     }
  590.     thread_detach(t);
  591.     task_kill(TASK->taskid);
  592. }
  593.  
  594. /** @}
  595.  */
  596.