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/*
* 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->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;
}