/*
* Copyright (c) 2001-2004 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup genericproc
* @{
*/
/**
* @file
* @brief Task management.
*/
#include <main/uinit.h>
#include <proc/thread.h>
#include <proc/task.h>
#include <proc/uarg.h>
#include <mm/as.h>
#include <mm/slab.h>
#include <atomic.h>
#include <synch/spinlock.h>
#include <synch/waitq.h>
#include <arch.h>
#include <panic.h>
#include <adt/avl.h>
#include <adt/btree.h>
#include <adt/list.h>
#include <ipc/ipc.h>
#include <security/cap.h>
#include <memstr.h>
#include <print.h>
#include <lib/elf.h>
#include <errno.h>
#include <func.h>
#include <syscall/copy.h>
#ifndef LOADED_PROG_STACK_PAGES_NO
#define LOADED_PROG_STACK_PAGES_NO 1
#endif
/** Spinlock protecting the tasks_tree AVL tree. */
SPINLOCK_INITIALIZE(tasks_lock);
/** AVL tree of active tasks.
*
* The task is guaranteed to exist after it was found in the tasks_tree as
* long as:
* @li the tasks_lock is held,
* @li the task's lock is held when task's lock is acquired before releasing
* tasks_lock or
* @li the task's refcount is greater than 0
*
*/
avltree_t tasks_tree;
static task_id_t task_counter = 0;
/**
* Points to the binary image used as the program loader. All non-initial
* tasks are created from this executable image.
*/
void *program_loader = NULL;
/** Initialize tasks
*
* Initialize kernel tasks support.
*
*/
void task_init(void)
{
TASK = NULL;
avltree_create(&tasks_tree);
}
/*
* The idea behind this walker is to remember a single task different from TASK.
*/
static bool task_done_walker(avltree_node_t *node, void *arg)
{
task_t *t = avltree_get_instance(node, task_t, tasks_tree_node);
task_t **tp = (task_t **) arg;
if (t != TASK) {
*tp = t;
return false; /* stop walking */
}
return true; /* continue the walk */
}
/** Kill all tasks except the current task.
*
*/
void task_done(void)
{
task_t *t;
do { /* Repeat until there are any tasks except TASK */
/* Messing with task structures, avoid deadlock */
ipl_t ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
t = NULL;
avltree_walk(&tasks_tree, task_done_walker, &t);
if (t != NULL) {
task_id_t id = t->taskid;
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
#ifdef CONFIG_DEBUG
printf("Killing task %llu\n", id
); #endif
task_kill(id);
thread_usleep(10000);
} else {
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
}
} while (t != NULL);
}
/** Create new task
*
* Create new task with no threads.
*
* @param as Task's address space.
* @param name Symbolic name.
*
* @return New task's structure
*
*/
task_t *task_create(as_t *as, char *name)
{
ipl_t ipl;
task_t *ta;
int i;
ta
= (task_t
*) malloc(sizeof(task_t
), 0);
task_create_arch(ta);
spinlock_initialize(&ta->lock, "task_ta_lock");
list_initialize(&ta->th_head);
ta->as = as;
ta->name = name;
atomic_set(&ta->refcount, 0);
atomic_set(&ta->lifecount, 0);
ta->context = CONTEXT;
ta->capabilities = 0;
ta->cycles = 0;
ipc_answerbox_init(&ta->answerbox, ta);
for (i = 0; i < IPC_MAX_PHONES; i++)
ipc_phone_init(&ta->phones[i]);
if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context,
ta->context)))
ipc_phone_connect(&ta->phones[0], ipc_phone_0);
atomic_set(&ta->active_calls, 0);
mutex_initialize(&ta->futexes_lock);
btree_create(&ta->futexes);
ipl = interrupts_disable();
/*
* Increment address space reference count.
*/
atomic_inc(&as->refcount);
spinlock_lock(&tasks_lock);
ta->taskid = ++task_counter;
avltree_node_initialize(&ta->tasks_tree_node);
ta->tasks_tree_node.key = ta->taskid;
avltree_insert(&tasks_tree, &ta->tasks_tree_node);
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ta;
}
/** Destroy task.
*
* @param t Task to be destroyed.
*/
void task_destroy(task_t *t)
{
/*
* Remove the task from the task B+tree.
*/
spinlock_lock(&tasks_lock);
avltree_delete(&tasks_tree, &t->tasks_tree_node);
spinlock_unlock(&tasks_lock);
/*
* Perform architecture specific task destruction.
*/
task_destroy_arch(t);
/*
* Free up dynamically allocated state.
*/
btree_destroy(&t->futexes);
/*
* Drop our reference to the address space.
*/
if (atomic_predec(&t->as->refcount) == 0)
as_destroy(t->as);
TASK = NULL;
}
/** Create new task with 1 thread and run it
*
* @param as Address space containing a binary program image.
* @param entry_addr Program entry-point address in program address space.
* @param name Program name.
*
* @return Task of the running program or NULL on error.
*/
task_t *task_create_from_as(as_t *as, uintptr_t entry_addr, char *name)
{
as_area_t *a;
thread_t *t;
task_t *task;
uspace_arg_t *kernel_uarg;
kernel_uarg
= (uspace_arg_t
*) malloc(sizeof(uspace_arg_t
), 0); kernel_uarg->uspace_entry = (void *) entry_addr;
kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
kernel_uarg->uspace_thread_function = NULL;
kernel_uarg->uspace_thread_arg = NULL;
kernel_uarg->uspace_uarg = NULL;
task = task_create(as, name);
ASSERT(task);
/*
* Create the data as_area.
*/
a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
LOADED_PROG_STACK_PAGES_NO * PAGE_SIZE, USTACK_ADDRESS,
AS_AREA_ATTR_NONE, &anon_backend, NULL);
/*
* Create the main thread.
*/
t = thread_create(uinit, kernel_uarg, task, THREAD_FLAG_USPACE,
"uinit", false);
ASSERT(t);
return task;
}
/** Parse an executable image in the physical memory.
*
* If the image belongs to a program loader, it is registered as such,
* (and *task is set to NULL). Otherwise a task is created from the
* executable image. The task is returned in *task.
*
* @param program_addr Address of program executable image.
* @param name Program name.
* @param task Where to store the pointer to the newly created task.
*
* @return EOK on success or negative error code.
*/
int task_parse_initial(void *program_addr, char *name, task_t **task)
{
as_t *as;
unsigned int rc;
as = as_create(0);
ASSERT(as);
rc = elf_load((elf_header_t *) program_addr, as, 0);
if (rc != EE_OK) {
as_destroy(as);
*task = NULL;
if (rc != EE_LOADER)
return ENOTSUP;
/* Register image as the program loader */
ASSERT(program_loader == NULL);
program_loader = program_addr;
return EOK;
}
*task = task_create_from_as(as, ((elf_header_t *) program_addr)->e_entry,
name);
return EOK;
}
/** Create a task from the program loader image.
*
* @param program_addr Address of program executable image.
* @param name Program name.
*
* @return Task of the running program or NULL on error.
*/
task_t *task_create_from_loader(char *name)
{
as_t *as;
unsigned int rc;
as = as_create(0);
ASSERT(as);
rc = elf_load((elf_header_t *) program_loader, as, ELD_F_LOADER);
if (rc != EE_OK) {
as_destroy(as);
return NULL;
}
return task_create_from_as(
as, ((elf_header_t *) program_loader)->e_entry, name);
}
/** Make task ready.
*
* Switch task's thread to the ready state.
*
* @param ta Task to make ready.
*/
void task_ready(task_t *t)
{
thread_t *th;
th = list_get_instance(t->th_head.next, thread_t, th_link);
thread_ready(th);
}
/** Syscall for reading task ID from userspace.
*
* @param uspace_task_id Userspace address of 8-byte buffer where to store
* current task ID.
*
* @return 0 on success or an error code from @ref errno.h.
*/
unative_t sys_task_get_id(task_id_t *uspace_task_id)
{
/*
* No need to acquire lock on TASK because taskid
* remains constant for the lifespan of the task.
*/
return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid,
sizeof(TASK->taskid));
}
/** Syscall for creating a new task from userspace.
*
* Creates a new task from the program loader image and stores its
* task id into the provided buffer.
*
* @param uspace_task_id Userspace address of 8-byte buffer where to store
* current task ID.
*
* @return 0 on success or an error code from @ref errno.h.
*/
unative_t sys_task_spawn(task_id_t *uspace_task_id)
{
task_t *t;
task_id_t fake_id;
int rc;
/* Before we even try creating the task, see if we can write the id */
rc = (unative_t) copy_to_uspace(uspace_task_id, &fake_id,
sizeof(fake_id));
if (rc != 0)
return rc;
t = task_create_from_loader("loader");
/* No need to aquire lock before task_ready() */
rc = (unative_t) copy_to_uspace(uspace_task_id, &t->taskid,
sizeof(t->taskid));
if (rc != 0) {
/* Ooops */
task_kill(t->taskid);
return rc;
}
task_ready(t);
return EOK;
}
/** Find task structure corresponding to task ID.
*
* The tasks_lock must be already held by the caller of this function
* and interrupts must be disabled.
*
* @param id Task ID.
*
* @return Task structure address or NULL if there is no such task ID.
*/
task_t *task_find_by_id(task_id_t id)
{
avltree_node_t *node;
node = avltree_search(&tasks_tree, (avltree_key_t) id);
if (node)
return avltree_get_instance(node, task_t, tasks_tree_node);
return NULL;
}
/** Get accounting data of given task.
*
* Note that task lock of 't' must be already held and
* interrupts must be already disabled.
*
* @param t Pointer to thread.
*
*/
uint64_t task_get_accounting(task_t *t)
{
/* Accumulated value of task */
uint64_t ret = t->cycles;
/* Current values of threads */
link_t *cur;
for (cur = t->th_head.next; cur != &t->th_head; cur = cur->next) {
thread_t *thr = list_get_instance(cur, thread_t, th_link);
spinlock_lock(&thr->lock);
/* Process only counted threads */
if (!thr->uncounted) {
if (thr == THREAD) {
/* Update accounting of current thread */
thread_update_accounting();
}
ret += thr->cycles;
}
spinlock_unlock(&thr->lock);
}
return ret;
}
/** Kill task.
*
* This function is idempotent.
* It signals all the task's threads to bail it out.
*
* @param id ID of the task to be killed.
*
* @return 0 on success or an error code from errno.h
*/
int task_kill(task_id_t id)
{
ipl_t ipl;
task_t *ta;
link_t *cur;
if (id == 1)
return EPERM;
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
if (!(ta = task_find_by_id(id))) {
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ENOENT;
}
spinlock_unlock(&tasks_lock);
/*
* Interrupt all threads except ktaskclnp.
*/
spinlock_lock(&ta->lock);
for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
thread_t *thr;
bool sleeping = false;
thr = list_get_instance(cur, thread_t, th_link);
spinlock_lock(&thr->lock);
thr->interrupted = true;
if (thr->state == Sleeping)
sleeping = true;
spinlock_unlock(&thr->lock);
if (sleeping)
waitq_interrupt_sleep(thr);
}
spinlock_unlock(&ta->lock);
interrupts_restore(ipl);
return 0;
}
static bool task_print_walker(avltree_node_t *node, void *arg)
{
task_t *t = avltree_get_instance(node, task_t, tasks_tree_node);
int j;
spinlock_lock(&t->lock);
uint64_t cycles;
char suffix;
order(task_get_accounting(t), &cycles, &suffix);
if (sizeof(void *) == 4)
printf("%-6llu %-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));
else
printf("%-6llu %-10s %-3ld %#18zx %#18zx %9llu%c %7zd %6zd", t->taskid, t->name, t->context, t, t->as, cycles, suffix,
t->refcount, atomic_get(&t->active_calls));
for (j = 0; j < IPC_MAX_PHONES; j++) {
if (t->phones[j].callee)
printf(" %zd:%#zx", j
, t
->phones
[j
].
callee); }
spinlock_unlock(&t->lock);
return true;
}
/** Print task list */
void task_print_list(void)
{
ipl_t ipl;
/* Messing with task structures, avoid deadlock */
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
if (sizeof(void *) == 4) {
printf("taskid name ctx address as " "cycles threads calls callee\n");
printf("------ ---------- --- ---------- ---------- " "---------- ------- ------ ------>\n");
} else {
printf("taskid name ctx address as " "cycles threads calls callee\n");
printf("------ ---------- --- ------------------ ------------------ " "---------- ------- ------ ------>\n");
}
avltree_walk(&tasks_tree, task_print_walker, NULL);
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
}
/** @}
*/