Subversion Repositories HelenOS

Rev

Rev 2227 | Rev 2504 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  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;
  111.             cur != &tasks_btree.leaf_head; cur = cur->next) {
  112.             btree_node_t *node;
  113.            
  114.             node = list_get_instance(cur, btree_node_t, leaf_link);
  115.            
  116.             unsigned int i;
  117.             for (i = 0; i < node->keys; i++) {
  118.                 if ((task_t *) node->value[i] != TASK) {
  119.                     t = (task_t *) node->value[i];
  120.                     break;
  121.                 }
  122.             }
  123.         }
  124.        
  125.         if (t != NULL) {
  126.             task_id_t id = t->taskid;
  127.            
  128.             spinlock_unlock(&tasks_lock);
  129.             interrupts_restore(ipl);
  130.            
  131. #ifdef CONFIG_DEBUG
  132.             printf("Killing task %llu\n", id);
  133. #endif         
  134.             task_kill(id);
  135.         } else {
  136.             spinlock_unlock(&tasks_lock);
  137.             interrupts_restore(ipl);
  138.         }
  139.        
  140.     } while (t != NULL);
  141. }
  142.  
  143. /** Create new task
  144.  *
  145.  * Create new task with no threads.
  146.  *
  147.  * @param as Task's address space.
  148.  * @param name Symbolic name.
  149.  *
  150.  * @return New task's structure
  151.  *
  152.  */
  153. task_t *task_create(as_t *as, char *name)
  154. {
  155.     ipl_t ipl;
  156.     task_t *ta;
  157.     int i;
  158.    
  159.     ta = (task_t *) malloc(sizeof(task_t), 0);
  160.  
  161.     task_create_arch(ta);
  162.  
  163.     spinlock_initialize(&ta->lock, "task_ta_lock");
  164.     list_initialize(&ta->th_head);
  165.     ta->as = as;
  166.     ta->name = name;
  167.     ta->main_thread = NULL;
  168.     ta->refcount = 0;
  169.     ta->context = CONTEXT;
  170.  
  171.     ta->capabilities = 0;
  172.     ta->accept_new_threads = true;
  173.     ta->cycles = 0;
  174.    
  175.     ipc_answerbox_init(&ta->answerbox);
  176.     for (i = 0; i < IPC_MAX_PHONES; i++)
  177.         ipc_phone_init(&ta->phones[i]);
  178.     if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context,
  179.         ta->context)))
  180.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  181.     atomic_set(&ta->active_calls, 0);
  182.  
  183.     mutex_initialize(&ta->futexes_lock);
  184.     btree_create(&ta->futexes);
  185.    
  186.     ipl = interrupts_disable();
  187.  
  188.     /*
  189.      * Increment address space reference count.
  190.      */
  191.     atomic_inc(&as->refcount);
  192.  
  193.     spinlock_lock(&tasks_lock);
  194.  
  195.     ta->taskid = ++task_counter;
  196.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  197.  
  198.     spinlock_unlock(&tasks_lock);
  199.     interrupts_restore(ipl);
  200.  
  201.     return ta;
  202. }
  203.  
  204. /** Destroy task.
  205.  *
  206.  * @param t Task to be destroyed.
  207.  */
  208. void task_destroy(task_t *t)
  209. {
  210.     task_destroy_arch(t);
  211.     btree_destroy(&t->futexes);
  212.  
  213.     if (atomic_predec(&t->as->refcount) == 0)
  214.         as_destroy(t->as);
  215.    
  216.     free(t);
  217.     TASK = NULL;
  218. }
  219.  
  220. /** Create new task with 1 thread and run it
  221.  *
  222.  * @param program_addr Address of program executable image.
  223.  * @param name Program name.
  224.  *
  225.  * @return Task of the running program or NULL on error.
  226.  */
  227. task_t *task_run_program(void *program_addr, char *name)
  228. {
  229.     as_t *as;
  230.     as_area_t *a;
  231.     int rc;
  232.     thread_t *t1, *t2;
  233.     task_t *task;
  234.     uspace_arg_t *kernel_uarg;
  235.  
  236.     as = as_create(0);
  237.     ASSERT(as);
  238.  
  239.     rc = elf_load((elf_header_t *) program_addr, as);
  240.     if (rc != EE_OK) {
  241.         as_destroy(as);
  242.         return NULL;
  243.     }
  244.    
  245.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  246.     kernel_uarg->uspace_entry =
  247.         (void *) ((elf_header_t *) program_addr)->e_entry;
  248.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  249.     kernel_uarg->uspace_thread_function = NULL;
  250.     kernel_uarg->uspace_thread_arg = NULL;
  251.     kernel_uarg->uspace_uarg = NULL;
  252.    
  253.     task = task_create(as, name);
  254.     ASSERT(task);
  255.  
  256.     /*
  257.      * Create the data as_area.
  258.      */
  259.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  260.         LOADED_PROG_STACK_PAGES_NO * PAGE_SIZE, USTACK_ADDRESS,
  261.         AS_AREA_ATTR_NONE, &anon_backend, NULL);
  262.  
  263.     /*
  264.      * Create the main thread.
  265.      */
  266.     t1 = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
  267.         "uinit", false);
  268.     ASSERT(t1);
  269.    
  270.     /*
  271.      * Create killer thread for the new task.
  272.      */
  273.     t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc", true);
  274.     ASSERT(t2);
  275.     thread_ready(t2);
  276.  
  277.     thread_ready(t1);
  278.  
  279.     return task;
  280. }
  281.  
  282. /** Syscall for reading task ID from userspace.
  283.  *
  284.  * @param uspace_task_id Userspace address of 8-byte buffer where to store
  285.  * current task ID.
  286.  *
  287.  * @return 0 on success or an error code from @ref errno.h.
  288.  */
  289. unative_t sys_task_get_id(task_id_t *uspace_task_id)
  290. {
  291.     /*
  292.      * No need to acquire lock on TASK because taskid
  293.      * remains constant for the lifespan of the task.
  294.      */
  295.     return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid,
  296.         sizeof(TASK->taskid));
  297. }
  298.  
  299. /** Find task structure corresponding to task ID.
  300.  *
  301.  * The tasks_lock must be already held by the caller of this function
  302.  * and interrupts must be disabled.
  303.  *
  304.  * @param id Task ID.
  305.  *
  306.  * @return Task structure address or NULL if there is no such task ID.
  307.  */
  308. task_t *task_find_by_id(task_id_t id)
  309. {
  310.     btree_node_t *leaf;
  311.    
  312.     return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
  313. }
  314.  
  315. /** Get accounting data of given task.
  316.  *
  317.  * Note that task lock of 't' must be already held and
  318.  * interrupts must be already disabled.
  319.  *
  320.  * @param t Pointer to thread.
  321.  *
  322.  */
  323. uint64_t task_get_accounting(task_t *t)
  324. {
  325.     /* Accumulated value of task */
  326.     uint64_t ret = t->cycles;
  327.    
  328.     /* Current values of threads */
  329.     link_t *cur;
  330.     for (cur = t->th_head.next; cur != &t->th_head; cur = cur->next) {
  331.         thread_t *thr = list_get_instance(cur, thread_t, th_link);
  332.        
  333.         spinlock_lock(&thr->lock);
  334.         /* Process only counted threads */
  335.         if (!thr->uncounted) {
  336.             if (thr == THREAD) {
  337.                 /* Update accounting of current thread */
  338.                 thread_update_accounting();
  339.             }
  340.             ret += thr->cycles;
  341.         }
  342.         spinlock_unlock(&thr->lock);
  343.     }
  344.    
  345.     return ret;
  346. }
  347.  
  348. /** Kill task.
  349.  *
  350.  * @param id ID of the task to be killed.
  351.  *
  352.  * @return 0 on success or an error code from errno.h
  353.  */
  354. int task_kill(task_id_t id)
  355. {
  356.     ipl_t ipl;
  357.     task_t *ta;
  358.     thread_t *t;
  359.     link_t *cur;
  360.  
  361.     if (id == 1)
  362.         return EPERM;
  363.    
  364.     ipl = interrupts_disable();
  365.     spinlock_lock(&tasks_lock);
  366.  
  367.     if (!(ta = task_find_by_id(id))) {
  368.         spinlock_unlock(&tasks_lock);
  369.         interrupts_restore(ipl);
  370.         return ENOENT;
  371.     }
  372.  
  373.     spinlock_lock(&ta->lock);
  374.     ta->refcount++;
  375.     spinlock_unlock(&ta->lock);
  376.  
  377.     btree_remove(&tasks_btree, ta->taskid, NULL);
  378.     spinlock_unlock(&tasks_lock);
  379.    
  380.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp", true);
  381.    
  382.     spinlock_lock(&ta->lock);
  383.     ta->accept_new_threads = false;
  384.     ta->refcount--;
  385.  
  386.     /*
  387.      * Interrupt all threads except ktaskclnp.
  388.      */
  389.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  390.         thread_t *thr;
  391.         bool  sleeping = false;
  392.        
  393.         thr = list_get_instance(cur, thread_t, th_link);
  394.         if (thr == t)
  395.             continue;
  396.            
  397.         spinlock_lock(&thr->lock);
  398.         thr->interrupted = true;
  399.         if (thr->state == Sleeping)
  400.             sleeping = true;
  401.         spinlock_unlock(&thr->lock);
  402.        
  403.         if (sleeping)
  404.             waitq_interrupt_sleep(thr);
  405.     }
  406.    
  407.     spinlock_unlock(&ta->lock);
  408.     interrupts_restore(ipl);
  409.    
  410.     if (t)
  411.         thread_ready(t);
  412.  
  413.     return 0;
  414. }
  415.  
  416. /** Print task list */
  417. void task_print_list(void)
  418. {
  419.     link_t *cur;
  420.     ipl_t ipl;
  421.    
  422.     /* Messing with task structures, avoid deadlock */
  423.     ipl = interrupts_disable();
  424.     spinlock_lock(&tasks_lock);
  425.    
  426.     printf("taskid name       ctx address    as         cycles     threads "
  427.         "calls  callee\n");
  428.     printf("------ ---------- --- ---------- ---------- ---------- ------- "        "------ ------>\n");
  429.  
  430.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head;
  431.         cur = cur->next) {
  432.         btree_node_t *node;
  433.         unsigned int i;
  434.        
  435.         node = list_get_instance(cur, btree_node_t, leaf_link);
  436.         for (i = 0; i < node->keys; i++) {
  437.             task_t *t;
  438.             int j;
  439.  
  440.             t = (task_t *) node->value[i];
  441.        
  442.             spinlock_lock(&t->lock);
  443.            
  444.             uint64_t cycles;
  445.             char suffix;
  446.             order(task_get_accounting(t), &cycles, &suffix);
  447.            
  448.             printf("%-6llu %-10s %-3ld %#10zx %#10zx %9llu%c %7zd "
  449.                 "%6zd", t->taskid, t->name, t->context, t, t->as,
  450.                 cycles, suffix, t->refcount,
  451.                 atomic_get(&t->active_calls));
  452.             for (j = 0; j < IPC_MAX_PHONES; j++) {
  453.                 if (t->phones[j].callee)
  454.                     printf(" %zd:%#zx", j,
  455.                         t->phones[j].callee);
  456.             }
  457.             printf("\n");
  458.            
  459.             spinlock_unlock(&t->lock);
  460.         }
  461.     }
  462.  
  463.     spinlock_unlock(&tasks_lock);
  464.     interrupts_restore(ipl);
  465. }
  466.  
  467. /** Kernel thread used to cleanup the task after it is killed. */
  468. void ktaskclnp(void *arg)
  469. {
  470.     ipl_t ipl;
  471.     thread_t *t = NULL, *main_thread;
  472.     link_t *cur;
  473.     bool again;
  474.  
  475.     thread_detach(THREAD);
  476.  
  477. loop:
  478.     ipl = interrupts_disable();
  479.     spinlock_lock(&TASK->lock);
  480.    
  481.     main_thread = TASK->main_thread;
  482.    
  483.     /*
  484.      * Find a thread to join.
  485.      */
  486.     again = false;
  487.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  488.         t = list_get_instance(cur, thread_t, th_link);
  489.  
  490.         spinlock_lock(&t->lock);
  491.         if (t == THREAD) {
  492.             spinlock_unlock(&t->lock);
  493.             continue;
  494.         } else if (t == main_thread) {
  495.             spinlock_unlock(&t->lock);
  496.             continue;
  497.         } else if (t->join_type != None) {
  498.             spinlock_unlock(&t->lock);
  499.             again = true;
  500.             continue;
  501.         } else {
  502.             t->join_type = TaskClnp;
  503.             spinlock_unlock(&t->lock);
  504.             again = false;
  505.             break;
  506.         }
  507.     }
  508.    
  509.     spinlock_unlock(&TASK->lock);
  510.     interrupts_restore(ipl);
  511.    
  512.     if (again) {
  513.         /*
  514.          * Other cleanup (e.g. ktaskgc) is in progress.
  515.          */
  516.         scheduler();
  517.         goto loop;
  518.     }
  519.    
  520.     if (t != THREAD) {
  521.         ASSERT(t != main_thread);   /* uninit is joined and detached
  522.                          * in ktaskgc */
  523.         thread_join(t);
  524.         thread_detach(t);
  525.         goto loop;          /* go for another thread */
  526.     }
  527.    
  528.     /*
  529.      * Now there are no other threads in this task
  530.      * and no new threads can be created.
  531.      */
  532.  
  533.     ipc_cleanup();
  534.     futex_cleanup();
  535.     klog_printf("Cleanup of task %llu completed.", TASK->taskid);
  536. }
  537.  
  538. /** Kernel thread used to kill the userspace task when its main thread exits.
  539.  *
  540.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  541.  * When this happens, the task is killed. In the meantime, exited threads
  542.  * are garbage collected.
  543.  *
  544.  * @param arg Pointer to the thread structure of the task's main thread.
  545.  */
  546. void ktaskgc(void *arg)
  547. {
  548.     thread_t *t = (thread_t *) arg;
  549. loop:  
  550.     /*
  551.      * Userspace threads cannot detach themselves,
  552.      * therefore the thread pointer is guaranteed to be valid.
  553.      */
  554.     if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) ==
  555.         ESYNCH_TIMEOUT) {   /* sleep uninterruptibly here! */
  556.         ipl_t ipl;
  557.         link_t *cur;
  558.         thread_t *thr = NULL;
  559.    
  560.         /*
  561.          * The join timed out. Try to do some garbage collection of
  562.          * Undead threads.
  563.          */
  564. more_gc:       
  565.         ipl = interrupts_disable();
  566.         spinlock_lock(&TASK->lock);
  567.        
  568.         for (cur = TASK->th_head.next; cur != &TASK->th_head;
  569.             cur = cur->next) {
  570.             thr = list_get_instance(cur, thread_t, th_link);
  571.             spinlock_lock(&thr->lock);
  572.             if (thr != t && thr->state == Undead &&
  573.                 thr->join_type == None) {
  574.                 thr->join_type = TaskGC;
  575.                 spinlock_unlock(&thr->lock);
  576.                 break;
  577.             }
  578.             spinlock_unlock(&thr->lock);
  579.             thr = NULL;
  580.         }
  581.         spinlock_unlock(&TASK->lock);
  582.         interrupts_restore(ipl);
  583.        
  584.         if (thr) {
  585.             thread_join(thr);
  586.             thread_detach(thr);
  587.             scheduler();
  588.             goto more_gc;
  589.         }
  590.            
  591.         goto loop;
  592.     }
  593.     thread_detach(t);
  594.     task_kill(TASK->taskid);
  595. }
  596.  
  597. /** @}
  598.  */
  599.