/*
* 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 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/cycle.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/avl.h>
#include <adt/list.h>
#include <time/clock.h>
#include <time/timeout.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>
#include <console/klog.h>
/** Thread states */
char *thread_states[] = {
"Invalid",
"Running",
"Sleeping",
"Ready",
"Entering",
"Exiting",
"Lingering"
};
/** Lock protecting the threads_tree AVL tree.
*
* For locking rules, see declaration thereof.
*/
SPINLOCK_INITIALIZE(threads_lock);
/** ALV tree of all threads.
*
* When a thread is found in the threads_tree AVL tree, it is guaranteed to
* exist as long as the threads_lock is held.
*/
avltree_t threads_tree;
SPINLOCK_INITIALIZE(tidlock);
thread_id_t 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;
THREAD->last_cycle = get_cycle();
/* This is where each thread wakes up after its creation */
spinlock_unlock(&THREAD->lock);
interrupts_enable();
f(arg);
/* Accumulate accounting to the task */
ipl_t ipl = interrupts_disable();
spinlock_lock(&THREAD->lock);
if (!THREAD->uncounted) {
thread_update_accounting();
uint64_t cycles = THREAD->cycles;
THREAD->cycles = 0;
spinlock_unlock(&THREAD->lock);
spinlock_lock(&TASK->lock);
TASK->cycles += cycles;
spinlock_unlock(&TASK->lock);
} else
spinlock_unlock(&THREAD->lock);
interrupts_restore(ipl);
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;
spinlock_initialize(&t->lock, "thread_t_lock");
link_initialize(&t->rq_link);
link_initialize(&t->wq_link);
link_initialize(&t->th_link);
/* call the architecture-specific part of the constructor */
thr_constructor_arch(t);
#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
t->kstack = (uint8_t *) frame_alloc(STACK_FRAMES, FRAME_KA | kmflags);
if (!t->kstack) {
#ifdef ARCH_HAS_FPU
if (t->saved_fpu_context)
slab_free(fpu_context_slab, t->saved_fpu_context);
#endif
return -1;
}
return 0;
}
/** Destruction of thread_t object */
static int thr_destructor(void *obj)
{
thread_t *t = (thread_t *) obj;
/* call the architecture-specific part of the destructor */
thr_destructor_arch(t);
frame_free(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
avltree_create(&threads_tree);
}
/** 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 & THREAD_FLAG_WIRED) {
ASSERT(t->cpu != NULL);
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);
}
/** 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.
* @param uncounted Thread's accounting doesn't affect accumulated task
* accounting.
*
* @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, bool uncounted)
{
thread_t *t;
ipl_t ipl;
t = (thread_t *) slab_alloc(thread_slab, 0);
if (!t)
return NULL;
/* Not needed, but good for debugging */
memsetb((uintptr_t) 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), (uintptr_t) 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->cycles = 0;
t->uncounted = uncounted;
t->priority = -1; /* start in rq[0] */
t->cpu = NULL;
t->flags = flags;
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;
avltree_node_initialize(&t->threads_tree_node);
t->threads_tree_node.key = (uintptr_t) t;
/* Init debugging stuff */
waitq_initialize(&t->go_wq);
t->debug_go_call = NULL;
t->uspace_state = NULL;
t->debug_stop = true;
t->debug_active = false;
/* might depend on previous initialization */
thread_create_arch(t);
if (!(flags & THREAD_FLAG_NOATTACH))
thread_attach(t, task);
return t;
}
/** 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)
{
ASSERT(t->state == Exiting || t->state == Lingering);
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);
avltree_delete(&threads_tree, &t->threads_tree_node);
spinlock_unlock(&threads_lock);
/*
* Detach from the containing task.
*/
spinlock_lock(&t->task->lock);
list_remove(&t->th_link);
spinlock_unlock(&t->task->lock);
/*
* t is guaranteed to be the very last thread of its task.
* It is safe to destroy the task.
*/
if (atomic_predec(&t->task->refcount) == 0)
task_destroy(t->task);
slab_free(thread_slab, t);
}
/** Make the thread visible to the system.
*
* Attach the thread structure to the current task and make it visible in the
* threads_tree.
*
* @param t Thread to be attached to the task.
* @param task Task to which the thread is to be attached.
*/
void thread_attach(thread_t *t, task_t *task)
{
ipl_t ipl;
/*
* Attach to the current task.
*/
ipl = interrupts_disable();
spinlock_lock(&task->lock);
atomic_inc(&task->refcount);
atomic_inc(&task->lifecount);
/* FIXME: this must be done very carefully.. an unstoppable
thread cannot appear just-so, it must be possible to catch it. */
if (t->flags & THREAD_FLAG_USPACE)
++task->not_stoppable_count;
list_append(&t->th_link, &task->th_head);
spinlock_unlock(&task->lock);
/*
* Register this thread in the system-wide list.
*/
spinlock_lock(&threads_lock);
avltree_insert(&threads_tree, &t->threads_tree_node);
spinlock_unlock(&threads_lock);
interrupts_restore(ipl);
}
/** Terminate thread.
*
* End current thread execution and switch it to the exiting state. All pending
* timeouts are executed.
*/
void thread_exit(void)
{
ipl_t ipl;
if (atomic_predec(&TASK->lifecount) == 0) {
/*
* We are the last thread in the task that still has not exited.
* With the exception of the moment the task was created, new
* threads can only be created by threads of the same task.
* We are safe to perform cleanup.
*/
if (THREAD->flags & THREAD_FLAG_USPACE) {
ipc_cleanup();
futex_cleanup();
klog_printf("Cleanup of task %llu completed.",
TASK->taskid);
}
}
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(uint32_t 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, uint32_t 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);
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
rc = waitq_sleep_timeout(&t->join_wq, usec, flags);
return rc;
}
/** Detach thread.
*
* Mark the thread as detached, if the thread is already in the Lingering
* state, deallocate its resources.
*
* @param t Thread to be detached.
*/
void thread_detach(thread_t *t)
{
ipl_t ipl;
/*
* Since the thread is expected not to be already detached,
* pointer to it must be still valid.
*/
ipl = interrupts_disable();
spinlock_lock(&t->lock);
ASSERT(!t->detached);
if (t->state == Lingering) {
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(uint32_t 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);
}
static bool thread_walker(avltree_node_t *node, void *arg)
{
thread_t *t;
t = avltree_get_instance(node, thread_t, threads_tree_node);
uint64_t cycles;
char suffix;
order(t->cycles, &cycles, &suffix);
if (sizeof(void *) == 4)
printf("%-6llu %-10s %#10zx %-8s %#10zx %-3ld %#10zx %#10zx %9llu%c ", t->tid, t->name, t, thread_states[t->state], t->task,
t->task->context, t->thread_code, t->kstack, cycles, suffix);
else
printf("%-6llu %-10s %#18zx %-8s %#18zx %-3ld %#18zx %#18zx %9llu%c ", t->tid, t->name, t, thread_states[t->state], t->task,
t->task->context, t->thread_code, t->kstack, cycles, suffix);
if (t->cpu)
else
if (t->state == Sleeping) {
if (sizeof(uintptr_t) == 4)
printf(" %#10zx", t
->sleep_queue
); else
printf(" %#18zx", t
->sleep_queue
); }
return true;
}
/** Print list of threads debug info */
void thread_print_list(void)
{
ipl_t ipl;
/* Messing with thread structures, avoid deadlock */
ipl = interrupts_disable();
spinlock_lock(&threads_lock);
if (sizeof(uintptr_t) == 4) {
printf("tid name address state task " "ctx code stack cycles cpu "
"waitqueue\n");
printf("------ ---------- ---------- -------- ---------- " "--- ---------- ---------- ---------- ---- "
"----------\n");
} else {
printf("tid name address state task " "ctx code stack cycles cpu "
"waitqueue\n");
printf("------ ---------- ------------------ -------- ------------------ " "--- ------------------ ------------------ ---------- ---- "
"------------------\n");
}
avltree_walk(&threads_tree, thread_walker, NULL);
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)
{
avltree_node_t *node;
node = avltree_search(&threads_tree, (avltree_key_t) ((uintptr_t) t));
return node != NULL;
}
/** Update accounting of current thread.
*
* Note that thread_lock on THREAD must be already held and
* interrupts must be already disabled.
*
*/
void thread_update_accounting(void)
{
uint64_t time = get_cycle
(); THREAD
->cycles
+= time - THREAD
->last_cycle
; THREAD
->last_cycle
= time;}
/** Process syscall to create new thread.
*
*/
unative_t sys_thread_create(uspace_arg_t *uspace_uarg, char *uspace_name,
thread_id_t *uspace_thread_id)
{
thread_t *t;
char namebuf[THREAD_NAME_BUFLEN];
uspace_arg_t *kernel_uarg;
int rc;
rc = copy_from_uspace(namebuf, uspace_name, THREAD_NAME_BUFLEN);
if (rc != 0)
return (unative_t) rc;
/*
* In case of failure, kernel_uarg will be deallocated in this function.
* In case of success, kernel_uarg will be freed in uinit().
*/
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) {
return (unative_t) rc;
}
t = thread_create(uinit, kernel_uarg, TASK,
THREAD_FLAG_USPACE | THREAD_FLAG_NOATTACH, namebuf, false);
if (t) {
if (uspace_thread_id != NULL) {
int rc;
rc = copy_to_uspace(uspace_thread_id, &t->tid,
sizeof(t->tid));
if (rc != 0) {
/*
* We have encountered a failure, but the thread
* has already been created. We need to undo its
* creation now.
*/
/*
* The new thread structure is initialized, but
* is still not visible to the system.
* We can safely deallocate it.
*/
slab_free(thread_slab, t);
return (unative_t) rc;
}
}
thread_attach(t, TASK);
thread_ready(t);
return 0;
} else
return (unative_t) ENOMEM;
}
/** Process syscall to terminate thread.
*
*/
unative_t sys_thread_exit(int uspace_status)
{
thread_exit();
/* Unreachable */
return 0;
}
/** Syscall for getting TID.
*
* @param uspace_thread_id Userspace address of 8-byte buffer where to store
* current thread ID.
*
* @return 0 on success or an error code from @ref errno.h.
*/
unative_t sys_thread_get_id(thread_id_t *uspace_thread_id)
{
/*
* No need to acquire lock on THREAD because tid
* remains constant for the lifespan of the thread.
*/
return (unative_t) copy_to_uspace(uspace_thread_id, &THREAD->tid,
sizeof(THREAD->tid));
}
/** @}
*/