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/tags/0.2.0/kernel/generic/src/proc/task.c
0,0 → 1,491
/*
* 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.
*/
 
/**
* @file task.c
* @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 <synch/spinlock.h>
#include <arch.h>
#include <panic.h>
#include <adt/btree.h>
#include <adt/list.h>
#include <ipc/ipc.h>
#include <security/cap.h>
#include <memstr.h>
#include <print.h>
#include <elf.h>
#include <errno.h>
#include <syscall/copy.h>
#include <console/klog.h>
 
#ifndef LOADED_PROG_STACK_PAGES_NO
#define LOADED_PROG_STACK_PAGES_NO 1
#endif
 
/** Spinlock protecting the tasks_btree B+tree. */
SPINLOCK_INITIALIZE(tasks_lock);
 
/** B+tree of active tasks.
*
* The task is guaranteed to exist after it was found in the tasks_btree 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 grater than 0
*
*/
btree_t tasks_btree;
 
static task_id_t task_counter = 0;
 
static void ktaskclnp(void *arg);
static void ktaskgc(void *arg);
 
/** Initialize tasks
*
* Initialize kernel tasks support.
*
*/
void task_init(void)
{
TASK = NULL;
btree_create(&tasks_btree);
}
 
 
/** 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;
ta->main_thread = NULL;
ta->refcount = 0;
 
ta->capabilities = 0;
ta->accept_new_threads = true;
ipc_answerbox_init(&ta->answerbox);
for (i=0; i < IPC_MAX_PHONES;i++)
ipc_phone_init(&ta->phones[i]);
if (ipc_phone_0)
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.
* TODO: Reconsider the locking scheme.
*/
mutex_lock(&as->lock);
as->refcount++;
mutex_unlock(&as->lock);
 
spinlock_lock(&tasks_lock);
 
ta->taskid = ++task_counter;
btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
 
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
 
return ta;
}
 
/** Destroy task.
*
* @param t Task to be destroyed.
*/
void task_destroy(task_t *t)
{
task_destroy_arch(t);
btree_destroy(&t->futexes);
 
mutex_lock_active(&t->as->lock);
if (--t->as->refcount == 0) {
mutex_unlock(&t->as->lock);
as_destroy(t->as);
/*
* t->as is destroyed.
*/
} else {
mutex_unlock(&t->as->lock);
}
free(t);
TASK = NULL;
}
 
/** Create new task with 1 thread and run it
*
* @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_run_program(void *program_addr, char *name)
{
as_t *as;
as_area_t *a;
int rc;
thread_t *t1, *t2;
task_t *task;
uspace_arg_t *kernel_uarg;
 
as = as_create(0);
ASSERT(as);
 
rc = elf_load((elf_header_t *) program_addr, as);
if (rc != EE_OK) {
as_destroy(as);
return NULL;
}
kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
kernel_uarg->uspace_entry = (void *) ((elf_header_t *) program_addr)->e_entry;
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.
*/
t1 = thread_create(uinit, kernel_uarg, task, 0, "uinit");
ASSERT(t1);
/*
* Create killer thread for the new task.
*/
t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc");
ASSERT(t2);
thread_ready(t2);
 
thread_ready(t1);
 
return task;
}
 
/** 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.
*/
__native 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 (__native) copy_to_uspace(uspace_task_id, &TASK->taskid, sizeof(TASK->taskid));
}
 
/** 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)
{
btree_node_t *leaf;
return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
}
 
/** Kill task.
*
* @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;
thread_t *t;
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_lock(&ta->lock);
ta->refcount++;
spinlock_unlock(&ta->lock);
 
btree_remove(&tasks_btree, ta->taskid, NULL);
spinlock_unlock(&tasks_lock);
t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp");
spinlock_lock(&ta->lock);
ta->accept_new_threads = false;
ta->refcount--;
 
/*
* Interrupt all threads except this one.
*/
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);
if (thr == t)
continue;
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);
if (t)
thread_ready(t);
 
return 0;
}
 
/** Print task list */
void task_print_list(void)
{
link_t *cur;
ipl_t ipl;
/* Messing with thread structures, avoid deadlock */
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
 
for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head; cur = cur->next) {
btree_node_t *node;
int i;
node = list_get_instance(cur, btree_node_t, leaf_link);
for (i = 0; i < node->keys; i++) {
task_t *t;
int j;
 
t = (task_t *) node->value[i];
spinlock_lock(&t->lock);
printf("%s(%lld): address=%#zX, as=%#zX, ActiveCalls: %zd",
t->name, t->taskid, t, t->as, atomic_get(&t->active_calls));
for (j=0; j < IPC_MAX_PHONES; j++) {
if (t->phones[j].callee)
printf(" Ph(%zd): %#zX ", j, t->phones[j].callee);
}
printf("\n");
spinlock_unlock(&t->lock);
}
}
 
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
}
 
/** Kernel thread used to cleanup the task after it is killed. */
void ktaskclnp(void *arg)
{
ipl_t ipl;
thread_t *t = NULL, *main_thread;
link_t *cur;
bool again;
 
thread_detach(THREAD);
 
loop:
ipl = interrupts_disable();
spinlock_lock(&TASK->lock);
main_thread = TASK->main_thread;
/*
* Find a thread to join.
*/
again = false;
for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
t = list_get_instance(cur, thread_t, th_link);
 
spinlock_lock(&t->lock);
if (t == THREAD) {
spinlock_unlock(&t->lock);
continue;
} else if (t == main_thread) {
spinlock_unlock(&t->lock);
continue;
} else if (t->join_type != None) {
spinlock_unlock(&t->lock);
again = true;
continue;
} else {
t->join_type = TaskClnp;
spinlock_unlock(&t->lock);
again = false;
break;
}
}
spinlock_unlock(&TASK->lock);
interrupts_restore(ipl);
if (again) {
/*
* Other cleanup (e.g. ktaskgc) is in progress.
*/
scheduler();
goto loop;
}
if (t != THREAD) {
ASSERT(t != main_thread); /* uninit is joined and detached in ktaskgc */
thread_join(t);
thread_detach(t);
goto loop; /* go for another thread */
}
/*
* Now there are no other threads in this task
* and no new threads can be created.
*/
ipc_cleanup();
futex_cleanup();
klog_printf("Cleanup of task %lld completed.", TASK->taskid);
}
 
/** Kernel task used to kill a userspace task when its main thread exits.
*
* This thread waits until the main userspace thread (i.e. uninit) exits.
* When this happens, the task is killed. In the meantime, exited threads
* are garbage collected.
*
* @param arg Pointer to the thread structure of the task's main thread.
*/
void ktaskgc(void *arg)
{
thread_t *t = (thread_t *) arg;
loop:
/*
* Userspace threads cannot detach themselves,
* therefore the thread pointer is guaranteed to be valid.
*/
if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) == ESYNCH_TIMEOUT) { /* sleep uninterruptibly here! */
ipl_t ipl;
link_t *cur;
thread_t *thr = NULL;
/*
* The join timed out. Try to do some garbage collection of Undead threads.
*/
more_gc:
ipl = interrupts_disable();
spinlock_lock(&TASK->lock);
for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
thr = list_get_instance(cur, thread_t, th_link);
spinlock_lock(&thr->lock);
if (thr->state == Undead && thr->join_type == None) {
thr->join_type = TaskGC;
spinlock_unlock(&thr->lock);
break;
}
spinlock_unlock(&thr->lock);
thr = NULL;
}
spinlock_unlock(&TASK->lock);
if (thr) {
thread_join(thr);
thread_detach(thr);
scheduler();
goto more_gc;
}
goto loop;
}
thread_detach(t);
task_kill(TASK->taskid);
}
/tags/0.2.0/kernel/generic/src/proc/thread.c
0,0 → 1,614
/*
* 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.
*/
 
/**
* @file thread.c
* @brief Thread management functions.
*/
 
#include <proc/scheduler.h>
#include <proc/thread.h>
#include <proc/task.h>
#include <proc/uarg.h>
#include <mm/frame.h>
#include <mm/page.h>
#include <arch/asm.h>
#include <arch.h>
#include <synch/synch.h>
#include <synch/spinlock.h>
#include <synch/waitq.h>
#include <synch/rwlock.h>
#include <cpu.h>
#include <func.h>
#include <context.h>
#include <adt/btree.h>
#include <adt/list.h>
#include <typedefs.h>
#include <time/clock.h>
#include <config.h>
#include <arch/interrupt.h>
#include <smp/ipi.h>
#include <arch/faddr.h>
#include <atomic.h>
#include <memstr.h>
#include <print.h>
#include <mm/slab.h>
#include <debug.h>
#include <main/uinit.h>
#include <syscall/copy.h>
#include <errno.h>
 
 
/** Thread states */
char *thread_states[] = {
"Invalid",
"Running",
"Sleeping",
"Ready",
"Entering",
"Exiting",
"Undead"
};
 
/** Lock protecting the threads_btree B+tree. For locking rules, see declaration thereof. */
SPINLOCK_INITIALIZE(threads_lock);
 
/** B+tree of all threads.
*
* When a thread is found in the threads_btree B+tree, it is guaranteed to exist as long
* as the threads_lock is held.
*/
btree_t threads_btree;
 
SPINLOCK_INITIALIZE(tidlock);
__u32 last_tid = 0;
 
static slab_cache_t *thread_slab;
#ifdef ARCH_HAS_FPU
slab_cache_t *fpu_context_slab;
#endif
 
/** Thread wrapper
*
* This wrapper is provided to ensure that every thread
* makes a call to thread_exit() when its implementing
* function returns.
*
* interrupts_disable() is assumed.
*
*/
static void cushion(void)
{
void (*f)(void *) = THREAD->thread_code;
void *arg = THREAD->thread_arg;
 
/* this is where each thread wakes up after its creation */
spinlock_unlock(&THREAD->lock);
interrupts_enable();
 
f(arg);
thread_exit();
/* not reached */
}
 
/** Initialization and allocation for thread_t structure */
static int thr_constructor(void *obj, int kmflags)
{
thread_t *t = (thread_t *)obj;
pfn_t pfn;
int status;
 
spinlock_initialize(&t->lock, "thread_t_lock");
link_initialize(&t->rq_link);
link_initialize(&t->wq_link);
link_initialize(&t->th_link);
#ifdef ARCH_HAS_FPU
# ifdef CONFIG_FPU_LAZY
t->saved_fpu_context = NULL;
# else
t->saved_fpu_context = slab_alloc(fpu_context_slab,kmflags);
if (!t->saved_fpu_context)
return -1;
# endif
#endif
 
pfn = frame_alloc_rc(STACK_FRAMES, FRAME_KA | kmflags,&status);
if (status) {
#ifdef ARCH_HAS_FPU
if (t->saved_fpu_context)
slab_free(fpu_context_slab,t->saved_fpu_context);
#endif
return -1;
}
t->kstack = (__u8 *)PA2KA(PFN2ADDR(pfn));
 
return 0;
}
 
/** Destruction of thread_t object */
static int thr_destructor(void *obj)
{
thread_t *t = (thread_t *)obj;
 
frame_free(ADDR2PFN(KA2PA(t->kstack)));
#ifdef ARCH_HAS_FPU
if (t->saved_fpu_context)
slab_free(fpu_context_slab,t->saved_fpu_context);
#endif
return 1; /* One page freed */
}
 
/** Initialize threads
*
* Initialize kernel threads support.
*
*/
void thread_init(void)
{
THREAD = NULL;
atomic_set(&nrdy,0);
thread_slab = slab_cache_create("thread_slab",
sizeof(thread_t),0,
thr_constructor, thr_destructor, 0);
#ifdef ARCH_HAS_FPU
fpu_context_slab = slab_cache_create("fpu_slab",
sizeof(fpu_context_t),
FPU_CONTEXT_ALIGN,
NULL, NULL, 0);
#endif
 
btree_create(&threads_btree);
}
 
/** Make thread ready
*
* Switch thread t to the ready state.
*
* @param t Thread to make ready.
*
*/
void thread_ready(thread_t *t)
{
cpu_t *cpu;
runq_t *r;
ipl_t ipl;
int i, avg;
 
ipl = interrupts_disable();
 
spinlock_lock(&t->lock);
 
ASSERT(! (t->state == Ready));
 
i = (t->priority < RQ_COUNT -1) ? ++t->priority : t->priority;
cpu = CPU;
if (t->flags & X_WIRED) {
cpu = t->cpu;
}
t->state = Ready;
spinlock_unlock(&t->lock);
/*
* Append t to respective ready queue on respective processor.
*/
r = &cpu->rq[i];
spinlock_lock(&r->lock);
list_append(&t->rq_link, &r->rq_head);
r->n++;
spinlock_unlock(&r->lock);
 
atomic_inc(&nrdy);
avg = atomic_get(&nrdy) / config.cpu_active;
atomic_inc(&cpu->nrdy);
 
interrupts_restore(ipl);
}
 
/** Destroy thread memory structure
*
* Detach thread from all queues, cpus etc. and destroy it.
*
* Assume thread->lock is held!!
*/
void thread_destroy(thread_t *t)
{
bool destroy_task = false;
 
ASSERT(t->state == Exiting || t->state == Undead);
ASSERT(t->task);
ASSERT(t->cpu);
 
spinlock_lock(&t->cpu->lock);
if(t->cpu->fpu_owner==t)
t->cpu->fpu_owner=NULL;
spinlock_unlock(&t->cpu->lock);
 
spinlock_unlock(&t->lock);
 
spinlock_lock(&threads_lock);
btree_remove(&threads_btree, (btree_key_t) ((__address ) t), NULL);
spinlock_unlock(&threads_lock);
 
/*
* Detach from the containing task.
*/
spinlock_lock(&t->task->lock);
list_remove(&t->th_link);
if (--t->task->refcount == 0) {
t->task->accept_new_threads = false;
destroy_task = true;
}
spinlock_unlock(&t->task->lock);
if (destroy_task)
task_destroy(t->task);
slab_free(thread_slab, t);
}
 
/** Create new thread
*
* Create a new thread.
*
* @param func Thread's implementing function.
* @param arg Thread's implementing function argument.
* @param task Task to which the thread belongs.
* @param flags Thread flags.
* @param name Symbolic name.
*
* @return New thread's structure on success, NULL on failure.
*
*/
thread_t *thread_create(void (* func)(void *), void *arg, task_t *task, int flags, char *name)
{
thread_t *t;
ipl_t ipl;
t = (thread_t *) slab_alloc(thread_slab, 0);
if (!t)
return NULL;
 
thread_create_arch(t);
/* Not needed, but good for debugging */
memsetb((__address)t->kstack, THREAD_STACK_SIZE * 1<<STACK_FRAMES, 0);
ipl = interrupts_disable();
spinlock_lock(&tidlock);
t->tid = ++last_tid;
spinlock_unlock(&tidlock);
interrupts_restore(ipl);
context_save(&t->saved_context);
context_set(&t->saved_context, FADDR(cushion), (__address) t->kstack, THREAD_STACK_SIZE);
the_initialize((the_t *) t->kstack);
ipl = interrupts_disable();
t->saved_context.ipl = interrupts_read();
interrupts_restore(ipl);
memcpy(t->name, name, THREAD_NAME_BUFLEN);
t->thread_code = func;
t->thread_arg = arg;
t->ticks = -1;
t->priority = -1; /* start in rq[0] */
t->cpu = NULL;
t->flags = 0;
t->state = Entering;
t->call_me = NULL;
t->call_me_with = NULL;
timeout_initialize(&t->sleep_timeout);
t->sleep_interruptible = false;
t->sleep_queue = NULL;
t->timeout_pending = 0;
 
t->in_copy_from_uspace = false;
t->in_copy_to_uspace = false;
 
t->interrupted = false;
t->join_type = None;
t->detached = false;
waitq_initialize(&t->join_wq);
t->rwlock_holder_type = RWLOCK_NONE;
t->task = task;
t->fpu_context_exists = 0;
t->fpu_context_engaged = 0;
/*
* Attach to the containing task.
*/
spinlock_lock(&task->lock);
if (!task->accept_new_threads) {
spinlock_unlock(&task->lock);
slab_free(thread_slab, t);
return NULL;
}
list_append(&t->th_link, &task->th_head);
if (task->refcount++ == 0)
task->main_thread = t;
spinlock_unlock(&task->lock);
 
/*
* Register this thread in the system-wide list.
*/
ipl = interrupts_disable();
spinlock_lock(&threads_lock);
btree_insert(&threads_btree, (btree_key_t) ((__address) t), (void *) t, NULL);
spinlock_unlock(&threads_lock);
interrupts_restore(ipl);
return t;
}
 
/** Make thread exiting
*
* End current thread execution and switch it to the exiting
* state. All pending timeouts are executed.
*
*/
void thread_exit(void)
{
ipl_t ipl;
 
restart:
ipl = interrupts_disable();
spinlock_lock(&THREAD->lock);
if (THREAD->timeout_pending) { /* busy waiting for timeouts in progress */
spinlock_unlock(&THREAD->lock);
interrupts_restore(ipl);
goto restart;
}
THREAD->state = Exiting;
spinlock_unlock(&THREAD->lock);
scheduler();
 
/* Not reached */
while (1)
;
}
 
 
/** Thread sleep
*
* Suspend execution of the current thread.
*
* @param sec Number of seconds to sleep.
*
*/
void thread_sleep(__u32 sec)
{
thread_usleep(sec*1000000);
}
 
/** Wait for another thread to exit.
*
* @param t Thread to join on exit.
* @param usec Timeout in microseconds.
* @param flags Mode of operation.
*
* @return An error code from errno.h or an error code from synch.h.
*/
int thread_join_timeout(thread_t *t, __u32 usec, int flags)
{
ipl_t ipl;
int rc;
 
if (t == THREAD)
return EINVAL;
 
/*
* Since thread join can only be called once on an undetached thread,
* the thread pointer is guaranteed to be still valid.
*/
ipl = interrupts_disable();
spinlock_lock(&t->lock);
 
ASSERT(!t->detached);
(void) waitq_sleep_prepare(&t->join_wq);
spinlock_unlock(&t->lock);
rc = waitq_sleep_timeout_unsafe(&t->join_wq, usec, flags);
waitq_sleep_finish(&t->join_wq, rc, ipl);
return rc;
}
 
/** Detach thread.
*
* Mark the thread as detached, if the thread is already in the Undead state,
* deallocate its resources.
*
* @param t Thread to be detached.
*/
void thread_detach(thread_t *t)
{
ipl_t ipl;
 
/*
* Since the thread is expected to not be already detached,
* pointer to it must be still valid.
*/
ipl = interrupts_disable();
spinlock_lock(&t->lock);
ASSERT(!t->detached);
if (t->state == Undead) {
thread_destroy(t); /* unlocks &t->lock */
interrupts_restore(ipl);
return;
} else {
t->detached = true;
}
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
}
 
/** Thread usleep
*
* Suspend execution of the current thread.
*
* @param usec Number of microseconds to sleep.
*
*/
void thread_usleep(__u32 usec)
{
waitq_t wq;
waitq_initialize(&wq);
 
(void) waitq_sleep_timeout(&wq, usec, SYNCH_FLAGS_NON_BLOCKING);
}
 
/** Register thread out-of-context invocation
*
* Register a function and its argument to be executed
* on next context switch to the current thread.
*
* @param call_me Out-of-context function.
* @param call_me_with Out-of-context function argument.
*
*/
void thread_register_call_me(void (* call_me)(void *), void *call_me_with)
{
ipl_t ipl;
ipl = interrupts_disable();
spinlock_lock(&THREAD->lock);
THREAD->call_me = call_me;
THREAD->call_me_with = call_me_with;
spinlock_unlock(&THREAD->lock);
interrupts_restore(ipl);
}
 
/** Print list of threads debug info */
void thread_print_list(void)
{
link_t *cur;
ipl_t ipl;
/* Messing with thread structures, avoid deadlock */
ipl = interrupts_disable();
spinlock_lock(&threads_lock);
 
for (cur = threads_btree.leaf_head.next; cur != &threads_btree.leaf_head; cur = cur->next) {
btree_node_t *node;
int i;
 
node = list_get_instance(cur, btree_node_t, leaf_link);
for (i = 0; i < node->keys; i++) {
thread_t *t;
t = (thread_t *) node->value[i];
printf("%s: address=%#zX, tid=%zd, state=%s, task=%#zX, code=%#zX, stack=%#zX, cpu=",
t->name, t, t->tid, thread_states[t->state], t->task, t->thread_code, t->kstack);
if (t->cpu)
printf("cpu%zd", t->cpu->id);
else
printf("none");
if (t->state == Sleeping) {
printf(", kst=%#zX", t->kstack);
printf(", wq=%#zX", t->sleep_queue);
}
printf("\n");
}
}
 
spinlock_unlock(&threads_lock);
interrupts_restore(ipl);
}
 
/** Check whether thread exists.
*
* Note that threads_lock must be already held and
* interrupts must be already disabled.
*
* @param t Pointer to thread.
*
* @return True if thread t is known to the system, false otherwise.
*/
bool thread_exists(thread_t *t)
{
btree_node_t *leaf;
return btree_search(&threads_btree, (btree_key_t) ((__address) t), &leaf) != NULL;
}
 
/** Process syscall to create new thread.
*
*/
__native sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name)
{
thread_t *t;
char namebuf[THREAD_NAME_BUFLEN];
uspace_arg_t *kernel_uarg;
__u32 tid;
int rc;
 
rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
if (rc != 0)
return (__native) rc;
 
kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
rc = copy_from_uspace(kernel_uarg, uspace_uarg, sizeof(uspace_arg_t));
if (rc != 0) {
free(kernel_uarg);
return (__native) rc;
}
 
if ((t = thread_create(uinit, kernel_uarg, TASK, 0, namebuf))) {
tid = t->tid;
thread_ready(t);
return (__native) tid;
} else {
free(kernel_uarg);
}
 
return (__native) ENOMEM;
}
 
/** Process syscall to terminate thread.
*
*/
__native sys_thread_exit(int uspace_status)
{
thread_exit();
/* Unreachable */
return 0;
}
/tags/0.2.0/kernel/generic/src/proc/scheduler.c
0,0 → 1,694
/*
* 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.
*/
 
/**
* @file scheduler.c
* @brief Scheduler and load balancing.
*
* This file contains the scheduler and kcpulb kernel thread which
* performs load-balancing of per-CPU run queues.
*/
 
#include <proc/scheduler.h>
#include <proc/thread.h>
#include <proc/task.h>
#include <mm/frame.h>
#include <mm/page.h>
#include <mm/as.h>
#include <time/delay.h>
#include <arch/asm.h>
#include <arch/faddr.h>
#include <atomic.h>
#include <synch/spinlock.h>
#include <config.h>
#include <context.h>
#include <func.h>
#include <arch.h>
#include <adt/list.h>
#include <panic.h>
#include <typedefs.h>
#include <cpu.h>
#include <print.h>
#include <debug.h>
 
static void before_task_runs(void);
static void before_thread_runs(void);
static void after_thread_ran(void);
static void scheduler_separated_stack(void);
 
atomic_t nrdy; /**< Number of ready threads in the system. */
 
/** Carry out actions before new task runs. */
void before_task_runs(void)
{
before_task_runs_arch();
}
 
/** Take actions before new thread runs.
*
* Perform actions that need to be
* taken before the newly selected
* tread is passed control.
*
* THREAD->lock is locked on entry
*
*/
void before_thread_runs(void)
{
before_thread_runs_arch();
#ifdef CONFIG_FPU_LAZY
if(THREAD==CPU->fpu_owner)
fpu_enable();
else
fpu_disable();
#else
fpu_enable();
if (THREAD->fpu_context_exists)
fpu_context_restore(THREAD->saved_fpu_context);
else {
fpu_init();
THREAD->fpu_context_exists=1;
}
#endif
}
 
/** Take actions after THREAD had run.
*
* Perform actions that need to be
* taken after the running thread
* had been preempted by the scheduler.
*
* THREAD->lock is locked on entry
*
*/
void after_thread_ran(void)
{
after_thread_ran_arch();
}
 
#ifdef CONFIG_FPU_LAZY
void scheduler_fpu_lazy_request(void)
{
restart:
fpu_enable();
spinlock_lock(&CPU->lock);
 
/* Save old context */
if (CPU->fpu_owner != NULL) {
spinlock_lock(&CPU->fpu_owner->lock);
fpu_context_save(CPU->fpu_owner->saved_fpu_context);
/* don't prevent migration */
CPU->fpu_owner->fpu_context_engaged=0;
spinlock_unlock(&CPU->fpu_owner->lock);
CPU->fpu_owner = NULL;
}
 
spinlock_lock(&THREAD->lock);
if (THREAD->fpu_context_exists) {
fpu_context_restore(THREAD->saved_fpu_context);
} else {
/* Allocate FPU context */
if (!THREAD->saved_fpu_context) {
/* Might sleep */
spinlock_unlock(&THREAD->lock);
spinlock_unlock(&CPU->lock);
THREAD->saved_fpu_context = slab_alloc(fpu_context_slab,
0);
/* We may have switched CPUs during slab_alloc */
goto restart;
}
fpu_init();
THREAD->fpu_context_exists=1;
}
CPU->fpu_owner=THREAD;
THREAD->fpu_context_engaged = 1;
spinlock_unlock(&THREAD->lock);
 
spinlock_unlock(&CPU->lock);
}
#endif
 
/** Initialize scheduler
*
* Initialize kernel scheduler.
*
*/
void scheduler_init(void)
{
}
 
/** Get thread to be scheduled
*
* Get the optimal thread to be scheduled
* according to thread accounting and scheduler
* policy.
*
* @return Thread to be scheduled.
*
*/
static thread_t *find_best_thread(void)
{
thread_t *t;
runq_t *r;
int i;
 
ASSERT(CPU != NULL);
 
loop:
interrupts_enable();
if (atomic_get(&CPU->nrdy) == 0) {
/*
* For there was nothing to run, the CPU goes to sleep
* until a hardware interrupt or an IPI comes.
* This improves energy saving and hyperthreading.
*/
 
/*
* An interrupt might occur right now and wake up a thread.
* In such case, the CPU will continue to go to sleep
* even though there is a runnable thread.
*/
 
cpu_sleep();
goto loop;
}
 
interrupts_disable();
for (i = 0; i<RQ_COUNT; i++) {
r = &CPU->rq[i];
spinlock_lock(&r->lock);
if (r->n == 0) {
/*
* If this queue is empty, try a lower-priority queue.
*/
spinlock_unlock(&r->lock);
continue;
}
 
atomic_dec(&CPU->nrdy);
atomic_dec(&nrdy);
r->n--;
 
/*
* Take the first thread from the queue.
*/
t = list_get_instance(r->rq_head.next, thread_t, rq_link);
list_remove(&t->rq_link);
 
spinlock_unlock(&r->lock);
 
spinlock_lock(&t->lock);
t->cpu = CPU;
 
t->ticks = us2ticks((i+1)*10000);
t->priority = i; /* correct rq index */
 
/*
* Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge.
*/
t->flags &= ~X_STOLEN;
spinlock_unlock(&t->lock);
 
return t;
}
goto loop;
 
}
 
/** Prevent rq starvation
*
* Prevent low priority threads from starving in rq's.
*
* When the function decides to relink rq's, it reconnects
* respective pointers so that in result threads with 'pri'
* greater or equal @start are moved to a higher-priority queue.
*
* @param start Threshold priority.
*
*/
static void relink_rq(int start)
{
link_t head;
runq_t *r;
int i, n;
 
list_initialize(&head);
spinlock_lock(&CPU->lock);
if (CPU->needs_relink > NEEDS_RELINK_MAX) {
for (i = start; i<RQ_COUNT-1; i++) {
/* remember and empty rq[i + 1] */
r = &CPU->rq[i + 1];
spinlock_lock(&r->lock);
list_concat(&head, &r->rq_head);
n = r->n;
r->n = 0;
spinlock_unlock(&r->lock);
/* append rq[i + 1] to rq[i] */
r = &CPU->rq[i];
spinlock_lock(&r->lock);
list_concat(&r->rq_head, &head);
r->n += n;
spinlock_unlock(&r->lock);
}
CPU->needs_relink = 0;
}
spinlock_unlock(&CPU->lock);
 
}
 
/** The scheduler
*
* The thread scheduling procedure.
* Passes control directly to
* scheduler_separated_stack().
*
*/
void scheduler(void)
{
volatile ipl_t ipl;
 
ASSERT(CPU != NULL);
 
ipl = interrupts_disable();
 
if (atomic_get(&haltstate))
halt();
if (THREAD) {
spinlock_lock(&THREAD->lock);
#ifndef CONFIG_FPU_LAZY
fpu_context_save(THREAD->saved_fpu_context);
#endif
if (!context_save(&THREAD->saved_context)) {
/*
* This is the place where threads leave scheduler();
*/
spinlock_unlock(&THREAD->lock);
interrupts_restore(THREAD->saved_context.ipl);
return;
}
 
/*
* Interrupt priority level of preempted thread is recorded here
* to facilitate scheduler() invocations from interrupts_disable()'d
* code (e.g. waitq_sleep_timeout()).
*/
THREAD->saved_context.ipl = ipl;
}
 
/*
* Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM
* and preemption counter. At this point THE could be coming either
* from THREAD's or CPU's stack.
*/
the_copy(THE, (the_t *) CPU->stack);
 
/*
* We may not keep the old stack.
* Reason: If we kept the old stack and got blocked, for instance, in
* find_best_thread(), the old thread could get rescheduled by another
* CPU and overwrite the part of its own stack that was also used by
* the scheduler on this CPU.
*
* Moreover, we have to bypass the compiler-generated POP sequence
* which is fooled by SP being set to the very top of the stack.
* Therefore the scheduler() function continues in
* scheduler_separated_stack().
*/
context_save(&CPU->saved_context);
context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE);
context_restore(&CPU->saved_context);
/* not reached */
}
 
/** Scheduler stack switch wrapper
*
* Second part of the scheduler() function
* using new stack. Handling the actual context
* switch to a new thread.
*
* Assume THREAD->lock is held.
*/
void scheduler_separated_stack(void)
{
int priority;
ASSERT(CPU != NULL);
if (THREAD) {
/* must be run after the switch to scheduler stack */
after_thread_ran();
 
switch (THREAD->state) {
case Running:
spinlock_unlock(&THREAD->lock);
thread_ready(THREAD);
break;
 
case Exiting:
repeat:
if (THREAD->detached) {
thread_destroy(THREAD);
} else {
/*
* The thread structure is kept allocated until somebody
* calls thread_detach() on it.
*/
if (!spinlock_trylock(&THREAD->join_wq.lock)) {
/*
* Avoid deadlock.
*/
spinlock_unlock(&THREAD->lock);
delay(10);
spinlock_lock(&THREAD->lock);
goto repeat;
}
_waitq_wakeup_unsafe(&THREAD->join_wq, false);
spinlock_unlock(&THREAD->join_wq.lock);
THREAD->state = Undead;
spinlock_unlock(&THREAD->lock);
}
break;
case Sleeping:
/*
* Prefer the thread after it's woken up.
*/
THREAD->priority = -1;
 
/*
* We need to release wq->lock which we locked in waitq_sleep().
* Address of wq->lock is kept in THREAD->sleep_queue.
*/
spinlock_unlock(&THREAD->sleep_queue->lock);
 
/*
* Check for possible requests for out-of-context invocation.
*/
if (THREAD->call_me) {
THREAD->call_me(THREAD->call_me_with);
THREAD->call_me = NULL;
THREAD->call_me_with = NULL;
}
 
spinlock_unlock(&THREAD->lock);
 
break;
 
default:
/*
* Entering state is unexpected.
*/
panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]);
break;
}
 
THREAD = NULL;
}
 
THREAD = find_best_thread();
spinlock_lock(&THREAD->lock);
priority = THREAD->priority;
spinlock_unlock(&THREAD->lock);
 
relink_rq(priority);
 
/*
* If both the old and the new task are the same, lots of work is avoided.
*/
if (TASK != THREAD->task) {
as_t *as1 = NULL;
as_t *as2;
 
if (TASK) {
spinlock_lock(&TASK->lock);
as1 = TASK->as;
spinlock_unlock(&TASK->lock);
}
 
spinlock_lock(&THREAD->task->lock);
as2 = THREAD->task->as;
spinlock_unlock(&THREAD->task->lock);
/*
* Note that it is possible for two tasks to share one address space.
*/
if (as1 != as2) {
/*
* Both tasks and address spaces are different.
* Replace the old one with the new one.
*/
as_switch(as1, as2);
}
TASK = THREAD->task;
before_task_runs();
}
 
spinlock_lock(&THREAD->lock);
THREAD->state = Running;
 
#ifdef SCHEDULER_VERBOSE
printf("cpu%d: tid %d (priority=%d,ticks=%lld,nrdy=%ld)\n", CPU->id, THREAD->tid, THREAD->priority, THREAD->ticks, atomic_get(&CPU->nrdy));
#endif
 
/*
* Some architectures provide late kernel PA2KA(identity)
* mapping in a page fault handler. However, the page fault
* handler uses the kernel stack of the running thread and
* therefore cannot be used to map it. The kernel stack, if
* necessary, is to be mapped in before_thread_runs(). This
* function must be executed before the switch to the new stack.
*/
before_thread_runs();
 
/*
* Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack.
*/
the_copy(THE, (the_t *) THREAD->kstack);
context_restore(&THREAD->saved_context);
/* not reached */
}
 
#ifdef CONFIG_SMP
/** Load balancing thread
*
* SMP load balancing thread, supervising thread supplies
* for the CPU it's wired to.
*
* @param arg Generic thread argument (unused).
*
*/
void kcpulb(void *arg)
{
thread_t *t;
int count, average, i, j, k = 0;
ipl_t ipl;
 
/*
* Detach kcpulb as nobody will call thread_join_timeout() on it.
*/
thread_detach(THREAD);
loop:
/*
* Work in 1s intervals.
*/
thread_sleep(1);
 
not_satisfied:
/*
* Calculate the number of threads that will be migrated/stolen from
* other CPU's. Note that situation can have changed between two
* passes. Each time get the most up to date counts.
*/
average = atomic_get(&nrdy) / config.cpu_active + 1;
count = average - atomic_get(&CPU->nrdy);
 
if (count <= 0)
goto satisfied;
 
/*
* Searching least priority queues on all CPU's first and most priority queues on all CPU's last.
*/
for (j=RQ_COUNT-1; j >= 0; j--) {
for (i=0; i < config.cpu_active; i++) {
link_t *l;
runq_t *r;
cpu_t *cpu;
 
cpu = &cpus[(i + k) % config.cpu_active];
 
/*
* Not interested in ourselves.
* Doesn't require interrupt disabling for kcpulb is X_WIRED.
*/
if (CPU == cpu)
continue;
if (atomic_get(&cpu->nrdy) <= average)
continue;
 
ipl = interrupts_disable();
r = &cpu->rq[j];
spinlock_lock(&r->lock);
if (r->n == 0) {
spinlock_unlock(&r->lock);
interrupts_restore(ipl);
continue;
}
t = NULL;
l = r->rq_head.prev; /* search rq from the back */
while (l != &r->rq_head) {
t = list_get_instance(l, thread_t, rq_link);
/*
* We don't want to steal CPU-wired threads neither threads already stolen.
* The latter prevents threads from migrating between CPU's without ever being run.
* We don't want to steal threads whose FPU context is still in CPU.
*/
spinlock_lock(&t->lock);
if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) {
/*
* Remove t from r.
*/
spinlock_unlock(&t->lock);
atomic_dec(&cpu->nrdy);
atomic_dec(&nrdy);
 
r->n--;
list_remove(&t->rq_link);
 
break;
}
spinlock_unlock(&t->lock);
l = l->prev;
t = NULL;
}
spinlock_unlock(&r->lock);
 
if (t) {
/*
* Ready t on local CPU
*/
spinlock_lock(&t->lock);
#ifdef KCPULB_VERBOSE
printf("kcpulb%d: TID %d -> cpu%d, nrdy=%ld, avg=%nd\n", CPU->id, t->tid, CPU->id, atomic_get(&CPU->nrdy), atomic_get(&nrdy) / config.cpu_active);
#endif
t->flags |= X_STOLEN;
t->state = Entering;
spinlock_unlock(&t->lock);
thread_ready(t);
 
interrupts_restore(ipl);
if (--count == 0)
goto satisfied;
/*
* We are not satisfied yet, focus on another CPU next time.
*/
k++;
continue;
}
interrupts_restore(ipl);
}
}
 
if (atomic_get(&CPU->nrdy)) {
/*
* Be a little bit light-weight and let migrated threads run.
*/
scheduler();
} else {
/*
* We failed to migrate a single thread.
* Give up this turn.
*/
goto loop;
}
goto not_satisfied;
 
satisfied:
goto loop;
}
 
#endif /* CONFIG_SMP */
 
 
/** Print information about threads & scheduler queues */
void sched_print_list(void)
{
ipl_t ipl;
int cpu,i;
runq_t *r;
thread_t *t;
link_t *cur;
 
/* We are going to mess with scheduler structures,
* let's not be interrupted */
ipl = interrupts_disable();
for (cpu=0;cpu < config.cpu_count; cpu++) {
 
if (!cpus[cpu].active)
continue;
 
spinlock_lock(&cpus[cpu].lock);
printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink);
for (i=0; i<RQ_COUNT; i++) {
r = &cpus[cpu].rq[i];
spinlock_lock(&r->lock);
if (!r->n) {
spinlock_unlock(&r->lock);
continue;
}
printf("\trq[%d]: ", i);
for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) {
t = list_get_instance(cur, thread_t, rq_link);
printf("%d(%s) ", t->tid,
thread_states[t->state]);
}
printf("\n");
spinlock_unlock(&r->lock);
}
spinlock_unlock(&cpus[cpu].lock);
}
interrupts_restore(ipl);
}
/tags/0.2.0/kernel/generic/src/proc/the.c
0,0 → 1,69
/*
* Copyright (C) 2005 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.
*/
 
/**
* @file the.c
* @brief THE structure functions.
*
* This file contains functions to manage the THE structure.
* The THE structure exists at the base address of every kernel
* stack and carries information about current settings
* (e.g. current CPU, current thread, task and address space
* and current preemption counter).
*/
 
#include <arch.h>
#include <typedefs.h>
 
 
/** Initialize THE structure
*
* Initialize THE structure passed as argument.
*
* @param the THE structure to be initialized.
*/
void the_initialize(the_t *the)
{
the->preemption_disabled = 0;
the->cpu = NULL;
the->thread = NULL;
the->task = NULL;
the->as = NULL;
}
 
/** Copy THE structure
*
* Copy the source THE structure to the destination THE structure.
*
* @param src The source THE structure.
* @param dst The destination THE structure.
*/
void the_copy(the_t *src, the_t *dst)
{
*dst = *src;
}