117 lines
2.4 KiB
C
117 lines
2.4 KiB
C
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#include <stdbool.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/kassert.h>
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#include <sys/kconfig.h>
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#include <sys/kdebug.h>
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#include <sys/ktime.h>
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#include <sys/mp.h>
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#include <sys/spinlock.h>
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#include <sys/semaphore.h>
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#include <sys/thread.h>
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Spinlock semaListLock = { 0, 0, 0, 0, 0, 0, "Semaphore List" };
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LIST_HEAD(SemaListHead, Semaphore) semaList = LIST_HEAD_INITIALIZER(semaList);
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extern uint64_t ticksPerSecond;
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void
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Semaphore_Init(Semaphore *sema, int count, const char *name)
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{
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Spinlock_Init(&sema->lock, name, SPINLOCK_TYPE_NORMAL);
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sema->count = count;
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strncpy(&sema->name[0], name, SEMAPHORE_NAMELEN);
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TAILQ_INIT(&sema->waiters);
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Spinlock_Lock(&semaListLock);
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LIST_INSERT_HEAD(&semaList, sema, semaphoreList);
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Spinlock_Unlock(&semaListLock);
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}
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void
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Semaphore_Destroy(Semaphore *sema)
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{
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Spinlock_Lock(&semaListLock);
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LIST_REMOVE(sema, semaphoreList);
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Spinlock_Unlock(&semaListLock);
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}
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void
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Semaphore_Acquire(Semaphore *sema)
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{
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Thread *cur = Sched_Current();
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while (1) {
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Spinlock_Lock(&sema->lock);
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if (sema->count > 0) {
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sema->count -= 1;
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Spinlock_Unlock(&sema->lock);
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Thread_Release(cur);
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return;
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}
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// Add to sleeper list
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TAILQ_INSERT_TAIL(&sema->waiters, cur, semaQueue);
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Sched_SetWaiting(cur);
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Spinlock_Unlock(&sema->lock);
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Sched_Scheduler();
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}
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}
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void
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Semaphore_Release(Semaphore *sema)
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{
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Thread *thr;
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Spinlock_Lock(&sema->lock);
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sema->count += 1;
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// Wakeup thread
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thr = TAILQ_FIRST(&sema->waiters);
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if (thr != NULL) {
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TAILQ_REMOVE(&sema->waiters, thr, semaQueue);
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Sched_SetRunnable(thr);
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}
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Spinlock_Unlock(&sema->lock);
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}
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bool
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Semaphore_TryAcquire(Semaphore *sema)
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{
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Spinlock_Lock(&sema->lock);
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if (sema->count > 0) {
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sema->count -= 1;
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Spinlock_Unlock(&sema->lock);
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return true;
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}
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Spinlock_Unlock(&sema->lock);
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return false;
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}
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void
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Debug_Semaphores(int argc, const char *argv[])
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{
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Semaphore *sema;
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Spinlock_Lock(&semaListLock);
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kprintf("%-36s Count\n", "Lock Name");
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LIST_FOREACH(sema, &semaList, semaphoreList)
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{
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Thread *thr;
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kprintf("%-36s %8d\n", sema->name, sema->count);
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TAILQ_FOREACH(thr, &sema->waiters, semaQueue) {
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kprintf("waiting: %d:%d\n", thr->proc->pid, thr->tid);
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}
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}
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Spinlock_Unlock(&semaListLock);
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}
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REGISTER_DBGCMD(semaphores, "Display list of semaphores", Debug_Semaphores);
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