source: mainline/kernel/generic/src/proc/task.c@ 33c0c649

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 33c0c649 was 95155b0c, checked in by Martin Decky <martin@…>, 19 years ago

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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. */
64SPINLOCK_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 */
74btree_t tasks_btree;
75
76static task_id_t task_counter = 0;
77
78static void ktaskclnp(void *arg);
79static void ktaskgc(void *arg);
80
81/** Initialize tasks
82 *
83 * Initialize kernel tasks support.
84 *
85 */
86void 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 */
103task_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 */
160void 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 */
186task_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 */
245unative_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 */
263task_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 */
278uint64_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 */
307int 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 */
370void 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. */
415void 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
424loop:
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 */
492void ktaskgc(void *arg)
493{
494 thread_t *t = (thread_t *) arg;
495loop:
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 */
508more_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 */
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