Annotation of prex-old/sys/kern/task.c, Revision 1.1
1.1 ! nbrk 1: /*-
! 2: * Copyright (c) 2005-2007, Kohsuke Ohtani
! 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: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice, this list of conditions and the following disclaimer in the
! 12: * documentation and/or other materials provided with the distribution.
! 13: * 3. Neither the name of the author nor the names of any co-contributors
! 14: * may be used to endorse or promote products derived from this software
! 15: * without specific prior written permission.
! 16: *
! 17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
! 18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
! 21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 27: * SUCH DAMAGE.
! 28: */
! 29:
! 30: /*
! 31: * task.c - task management routines
! 32: */
! 33:
! 34: #include <kernel.h>
! 35: #include <kmem.h>
! 36: #include <sched.h>
! 37: #include <thread.h>
! 38: #include <ipc.h>
! 39: #include <vm.h>
! 40: #include <page.h>
! 41: #include <task.h>
! 42:
! 43: /*
! 44: * Kernel task.
! 45: * kern_task acts as a list head of all tasks in the system.
! 46: */
! 47: struct task kern_task;
! 48:
! 49: /**
! 50: * task_create - create a new task.
! 51: *
! 52: * The child task will inherit some task states from its parent.
! 53: *
! 54: * Inherit status:
! 55: * Child data Inherit from parent ?
! 56: * ----------------- ---------------------
! 57: * Task name No
! 58: * Object list No
! 59: * Threads No
! 60: * Memory map New/Duplicate/Share
! 61: * Suspend count No
! 62: * Exception handler Yes
! 63: * Capability Yes
! 64: *
! 65: * If vm_option is VM_COPY, the child task will have the same memory
! 66: * image with the parent task. Especially, text region and read-only
! 67: * region are physically shared among them. VM_COPY is supported only
! 68: * with MMU system.
! 69: * The child task initially contains no threads.
! 70: */
! 71: int
! 72: task_create(task_t parent, int vm_option, task_t *child)
! 73: {
! 74: task_t task;
! 75: vm_map_t map = NULL;
! 76: int err = 0;
! 77:
! 78: switch (vm_option) {
! 79: case VM_NEW:
! 80: case VM_SHARE:
! 81: #ifdef CONFIG_MMU
! 82: case VM_COPY:
! 83: #endif
! 84: break;
! 85: default:
! 86: return EINVAL;
! 87: }
! 88: sched_lock();
! 89: if (!task_valid(parent)) {
! 90: err = ESRCH;
! 91: goto out;
! 92: }
! 93: if (cur_task() != &kern_task) {
! 94: if(!task_access(parent)) {
! 95: err = EPERM;
! 96: goto out;
! 97: }
! 98: /*
! 99: * Set zero as child task id before copying parent's
! 100: * memory space. So, the child task can identify
! 101: * whether it is a child.
! 102: */
! 103: task = 0;
! 104: if (umem_copyout(&task, child, sizeof(task_t))) {
! 105: err = EFAULT;
! 106: goto out;
! 107: }
! 108: }
! 109:
! 110: if ((task = kmem_alloc(sizeof(struct task))) == NULL) {
! 111: err = ENOMEM;
! 112: goto out;
! 113: }
! 114: memset(task, 0, sizeof(struct task));
! 115:
! 116: /*
! 117: * Setup VM mapping.
! 118: */
! 119: switch (vm_option) {
! 120: case VM_NEW:
! 121: map = vm_create();
! 122: break;
! 123: case VM_SHARE:
! 124: vm_reference(parent->map);
! 125: map = parent->map;
! 126: break;
! 127: case VM_COPY:
! 128: map = vm_fork(parent->map);
! 129: break;
! 130: }
! 131: if (map == NULL) {
! 132: kmem_free(task);
! 133: err = ENOMEM;
! 134: goto out;
! 135: }
! 136: /*
! 137: * Fill initial task data.
! 138: */
! 139: task->map = map;
! 140: task->exc_handler = parent->exc_handler;
! 141: task->capability = parent->capability;
! 142: task->parent = parent;
! 143: task->magic = TASK_MAGIC;
! 144: list_init(&task->objects);
! 145: list_init(&task->threads);
! 146: list_insert(&kern_task.link, &task->link);
! 147:
! 148: if (cur_task() == &kern_task)
! 149: *child = task;
! 150: else
! 151: err = umem_copyout(&task, child, sizeof(task_t));
! 152: out:
! 153: sched_unlock();
! 154: return err;
! 155: }
! 156:
! 157: /*
! 158: * Terminate the specified task.
! 159: */
! 160: int
! 161: task_terminate(task_t task)
! 162: {
! 163: int err = 0;
! 164: list_t head, n;
! 165: thread_t th;
! 166: object_t obj;
! 167:
! 168: sched_lock();
! 169: if (!task_valid(task)) {
! 170: sched_unlock();
! 171: return ESRCH;
! 172: }
! 173: if (!task_access(task)) {
! 174: sched_unlock();
! 175: return EPERM;
! 176: }
! 177:
! 178: /* Invalidate the task. */
! 179: task->magic = 0;
! 180:
! 181: /*
! 182: * Terminate all threads except a current thread.
! 183: */
! 184: head = &task->threads;
! 185: for (n = list_first(head); n != head; n = list_next(n)) {
! 186: th = list_entry(n, struct thread, task_link);
! 187: if (th != cur_thread)
! 188: thread_terminate(th);
! 189: }
! 190: /*
! 191: * Delete all objects owned by the target task.
! 192: */
! 193: head = &task->objects;
! 194: for (n = list_first(head); n != head; n = list_next(n)) {
! 195: /*
! 196: * A current task may not have the right to delete
! 197: * target objects. So, we set the owner of the object
! 198: * to the current task before deleting it.
! 199: */
! 200: obj = list_entry(n, struct object, task_link);
! 201: obj->owner = cur_task();
! 202: object_destroy(obj);
! 203: }
! 204: /*
! 205: * Release all other task related resources.
! 206: */
! 207: vm_terminate(task->map);
! 208: list_remove(&task->link);
! 209: kmem_free(task);
! 210:
! 211: if (task == cur_task()) {
! 212: cur_thread->task = NULL;
! 213: thread_terminate(cur_thread);
! 214: }
! 215: sched_unlock();
! 216: return err;
! 217: }
! 218:
! 219: task_t
! 220: task_self(void)
! 221: {
! 222:
! 223: return cur_task();
! 224: }
! 225:
! 226: /*
! 227: * Suspend a task.
! 228: */
! 229: int
! 230: task_suspend(task_t task)
! 231: {
! 232: list_t head, n;
! 233: thread_t th;
! 234: int err = 0;
! 235:
! 236: sched_lock();
! 237: if (!task_valid(task)) {
! 238: err = ESRCH;
! 239: } else if (!task_access(task)) {
! 240: err = EPERM;
! 241: } else if (++task->suspend_count == 1) {
! 242: /*
! 243: * Suspend all threads within the task.
! 244: */
! 245: head = &task->threads;
! 246: for (n = list_first(head); n != head; n = list_next(n)) {
! 247: th = list_entry(n, struct thread, task_link);
! 248: thread_suspend(th);
! 249: }
! 250: }
! 251: sched_unlock();
! 252: return err;
! 253: }
! 254:
! 255: /*
! 256: * Resume a task.
! 257: *
! 258: * A thread in the task will begin to run only when both
! 259: * thread suspend count and task suspend count become 0.
! 260: */
! 261: int
! 262: task_resume(task_t task)
! 263: {
! 264: list_t head, n;
! 265: thread_t th;
! 266: int err = 0;
! 267:
! 268: ASSERT(task != cur_task());
! 269:
! 270: sched_lock();
! 271: if (!task_valid(task)) {
! 272: err = ESRCH;
! 273: } else if (!task_access(task)) {
! 274: err = EPERM;
! 275: } else if (task->suspend_count == 0) {
! 276: err = EINVAL;
! 277: } else if (--task->suspend_count == 0) {
! 278: /*
! 279: * Resume all threads in the target task.
! 280: */
! 281: head = &task->threads;
! 282: for (n = list_first(head); n != head; n = list_next(n)) {
! 283: th = list_entry(n, struct thread, task_link);
! 284: thread_resume(th);
! 285: }
! 286: }
! 287: sched_unlock();
! 288: return err;
! 289: }
! 290:
! 291: /*
! 292: * Set task name.
! 293: *
! 294: * The naming service is separated from task_create() because
! 295: * the task name can be changed at anytime by exec().
! 296: */
! 297: int
! 298: task_name(task_t task, const char *name)
! 299: {
! 300: size_t len;
! 301: int err = 0;
! 302:
! 303: sched_lock();
! 304: if (!task_valid(task)) {
! 305: err = ESRCH;
! 306: } else if (!task_access(task)) {
! 307: err = EPERM;
! 308: } else {
! 309: if (cur_task() == &kern_task)
! 310: strlcpy(task->name, name, MAXTASKNAME);
! 311: else {
! 312: if (umem_strnlen(name, MAXTASKNAME, &len))
! 313: err = EFAULT;
! 314: else if (len >= MAXTASKNAME)
! 315: err = ENAMETOOLONG;
! 316: else
! 317: err = umem_copyin((void *)name, task->name,
! 318: len + 1);
! 319: }
! 320: }
! 321: sched_unlock();
! 322: return err;
! 323: }
! 324:
! 325: /*
! 326: * Get the capability of the specified task.
! 327: */
! 328: int
! 329: task_getcap(task_t task, cap_t *cap)
! 330: {
! 331: cap_t cur_cap;
! 332:
! 333: sched_lock();
! 334: if (!task_valid(task)) {
! 335: sched_unlock();
! 336: return ESRCH;
! 337: }
! 338: cur_cap = task->capability;
! 339: sched_unlock();
! 340:
! 341: return umem_copyout(&cur_cap, cap, sizeof(cap_t));
! 342: }
! 343:
! 344: /*
! 345: * Set the capability of the specified task.
! 346: */
! 347: int
! 348: task_setcap(task_t task, cap_t *cap)
! 349: {
! 350: cap_t new_cap;
! 351: int err = 0;
! 352:
! 353: if (!task_capable(CAP_SETPCAP))
! 354: return EPERM;
! 355:
! 356: sched_lock();
! 357: if (!task_valid(task)) {
! 358: err = ESRCH;
! 359: } else if (umem_copyin(cap, &new_cap, sizeof(cap_t))) {
! 360: err = EFAULT;
! 361: } else {
! 362: task->capability = new_cap;
! 363: }
! 364: sched_unlock();
! 365: return err;
! 366: }
! 367:
! 368: /*
! 369: * Check if the current task can access the specified task.
! 370: */
! 371: int
! 372: task_access(task_t task)
! 373: {
! 374:
! 375: return (task != &kern_task &&
! 376: (task == cur_task() || task->parent == cur_task() ||
! 377: task_capable(CAP_TASK)));
! 378: }
! 379:
! 380: /*
! 381: * Create and setup boot tasks.
! 382: */
! 383: void
! 384: task_bootstrap(void)
! 385: {
! 386: struct module *m;
! 387: task_t task;
! 388: thread_t th;
! 389: void *stack;
! 390: int i;
! 391:
! 392: m = &boot_info->tasks[0];
! 393: for (i = 0; i < boot_info->nr_tasks; i++, m++) {
! 394: /*
! 395: * Create a new task.
! 396: */
! 397: if (task_create(&kern_task, VM_NEW, &task))
! 398: break;
! 399: task_name(task, m->name);
! 400: if (vm_load(task->map, m, &stack))
! 401: break;
! 402:
! 403: /*
! 404: * Create and start a new thread.
! 405: */
! 406: if (thread_create(task, &th))
! 407: break;
! 408: stack = (void *)((u_long)stack + USTACK_SIZE - sizeof(int));
! 409: if (thread_load(th, (void (*)(void))m->entry, stack))
! 410: break;
! 411: thread_resume(th);
! 412: }
! 413: if (i != boot_info->nr_tasks)
! 414: panic("task_boot");
! 415: }
! 416:
! 417: #if defined(DEBUG) && defined(CONFIG_KDUMP)
! 418: void
! 419: task_dump(void)
! 420: {
! 421: list_t i, j;
! 422: task_t task;
! 423: int nobjs, nthreads;
! 424:
! 425: printk("Task dump:\n");
! 426: printk(" mod task nobjs nthrds vm map susp exc hdlr "
! 427: "cap name\n");
! 428: printk(" --- --------- ------ ------ -------- ---- -------- "
! 429: "-------- ------------\n");
! 430:
! 431: i = &kern_task.link;
! 432: do {
! 433: task = list_entry(i, struct task, link);
! 434:
! 435: nthreads = 0;
! 436: j = &task->threads;
! 437: j = list_next(j);
! 438: do {
! 439: nthreads++;
! 440: j = list_next(j);
! 441: } while (j != &task->threads);
! 442:
! 443: nobjs = 0;
! 444: j = &task->objects;
! 445: j = list_next(j);
! 446: do {
! 447: nobjs++;
! 448: j = list_next(j);
! 449: } while (j != &task->objects);
! 450:
! 451: printk(" %s %08x%c %3d %3d %08x %4d %08x %08x %s\n",
! 452: (task == &kern_task) ? "Knl" : "Usr",
! 453: task, (task == cur_task()) ? '*' : ' ', nobjs,
! 454: nthreads, task->map, task->suspend_count,
! 455: task->exc_handler, task->capability,
! 456: task->name ? task->name : "no name");
! 457:
! 458: i = list_next(i);
! 459: } while (i != &kern_task.link);
! 460: }
! 461:
! 462: void
! 463: boot_dump(void)
! 464: {
! 465: struct module *m;
! 466: int i;
! 467:
! 468: printk(" text base data base text size data size bss size "
! 469: "task name\n");
! 470: printk(" --------- --------- --------- --------- ---------- "
! 471: "----------\n");
! 472:
! 473: m = &boot_info->tasks[0];
! 474: for (i = 0; i < boot_info->nr_tasks; i++, m++) {
! 475: printk(" %8x %8x %8d %8d %8d %s\n",
! 476: m->text, m->data, m->textsz,
! 477: m->datasz, m->bsssz, m->name);
! 478: }
! 479: }
! 480: #endif
! 481:
! 482: void
! 483: task_init(void)
! 484: {
! 485: /*
! 486: * Create a kernel task as a first task in the system.
! 487: *
! 488: * Note: We assume the VM mapping for a kernel task has
! 489: * already been initialized in vm_init().
! 490: */
! 491: strlcpy(kern_task.name, "kernel", MAXTASKNAME);
! 492: list_init(&kern_task.link);
! 493: list_init(&kern_task.objects);
! 494: list_init(&kern_task.threads);
! 495: kern_task.capability = 0xffffffff;
! 496: kern_task.magic = TASK_MAGIC;
! 497: }
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