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#include <stdlib.h>
#include <stdbool.h>
#include <errno.h>
#include <pthread.h>
#include "/usr/include/semaphore.h"
#include "thread-internal.h"
#include "kernel.h"
#define NSEC_PER_SEC 1000000000L
static inline void timespec_add_ns(struct timespec *a, uint64_t ns)
{
lldiv_t q = lldiv(a->tv_nsec + ns, NSEC_PER_SEC);
a->tv_sec += q.quot;
a->tv_nsec = q.rem;
}
static int threads_initialized;
struct thread_init_data {
void (*function)(void);
bool start_frozen;
sem_t init_sem;
struct thread_entry *entry;
};
__thread struct thread_entry *_current;
unsigned int thread_self(void)
{
return (unsigned) pthread_self();
}
static struct thread_entry_item {
unsigned thread_id;
struct thread_entry *entry;
} entry_lookup[32];
static struct thread_entry_item *__find_thread_entry(unsigned thread_id)
{
int i;
for (i = 0; i < 32; i++)
{
if (entry_lookup[i].thread_id == thread_id)
return &entry_lookup[i];
}
return NULL;
}
static struct thread_entry *find_thread_entry(unsigned thread_id)
{
return __find_thread_entry(thread_id)->entry;
}
static void *trampoline(void *arg)
{
struct thread_init_data *data = arg;
void (*thread_fn)(void) = data->function;
_current = data->entry;
if (data->start_frozen)
{
struct corelock thaw_lock;
corelock_init(&thaw_lock);
corelock_lock(&thaw_lock);
_current->lock = &thaw_lock;
sem_post(&data->init_sem);
block_thread_switch(_current, _current->lock);
_current->lock = NULL;
corelock_unlock(&thaw_lock);
}
else
sem_post(&data->init_sem);
free(data);
thread_fn();
return NULL;
}
void thread_thaw(unsigned int thread_id)
{
struct thread_entry *e = find_thread_entry(thread_id);
if (e->lock)
{
corelock_lock(e->lock);
wakeup_thread(e);
corelock_unlock(e->lock);
}
/* else: no lock. must be running already */
}
void init_threads(void)
{
struct thread_entry_item *item0 = &entry_lookup[0];
item0->entry = calloc(1, sizeof(struct thread_entry));
item0->thread_id = pthread_self();
_current = item0->entry;
pthread_cond_init(&item0->entry->cond, NULL);
threads_initialized = 1;
}
unsigned int create_thread(void (*function)(void),
void* stack, size_t stack_size,
unsigned flags, const char *name
//~ IF_PRIO(, int priority)
IF_COP(, unsigned int core))
{
pthread_t retval;
struct thread_init_data *data = calloc(1, sizeof(struct thread_init_data));
struct thread_entry *entry = calloc(1, sizeof(struct thread_entry));
struct thread_entry_item *item;
if (!threads_initialized)
abort();
data->function = function;
data->start_frozen = flags & CREATE_THREAD_FROZEN;
data->entry = entry;
pthread_cond_init(&entry->cond, NULL);
entry->runnable = true;
sem_init(&data->init_sem, 0, 0);
if (pthread_create(&retval, NULL, trampoline, data) < 0)
return -1;
sem_wait(&data->init_sem);
item = __find_thread_entry(0);
item->thread_id = retval;
item->entry = entry;
pthread_setname_np(retval, name);
return retval;
}
/* for block_thread(), _w_tmp() and wakeup_thread() t->lock must point
* to a corelock instance, and this corelock must be held by the caller */
void block_thread_switch(struct thread_entry *t, struct corelock *cl)
{
t->runnable = false;
if (wait_queue_ptr(t))
wait_queue_register(t);
while(!t->runnable)
pthread_cond_wait(&t->cond, &cl->mutex);
}
void block_thread_switch_w_tmo(struct thread_entry *t, int timeout,
struct corelock *cl)
{
int err = 0;
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
timespec_add_ns(&ts, timeout * (NSEC_PER_SEC/HZ));
t->runnable = false;
wait_queue_register(t->wqp, t);
while(!t->runnable && !err)
err = pthread_cond_timedwait(&t->cond, &cl->mutex, &ts);
if (err == ETIMEDOUT)
{ /* the thread timed out and was not explicitely woken up.
* we need to do this now to mark it runnable again */
t->runnable = true;
/* NOTE: objects do their own removal upon timer expiration */
}
}
unsigned int wakeup_thread(struct thread_entry *t)
{
if (t->wqp)
wait_queue_remove(t);
t->runnable = true;
pthread_cond_signal(&t->cond);
return THREAD_OK;
}
void yield(void) {}
unsigned sleep(unsigned ticks)
{
struct timespec ts;
ts.tv_sec = ticks/HZ;
ts.tv_nsec = (ticks % HZ) * (NSEC_PER_SEC/HZ);
nanosleep(&ts, NULL);
return 0;
}
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