70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
// ke_mutex.c - binary ownership mutex
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#include "ke_mutex.h"
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#include "ke_thread.h"
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#include "ke_sched.h"
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#include "mm_virt.h"
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#include "ob_object.h"
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static void MutexDestroy(OBJECT* obj) { (void)obj; }
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KSTATUS MutexCreate(MUTEX **out) {
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if (!out) return STATUS_INVALID_PARAMETER;
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MUTEX* m = (MUTEX *)ObAllocateObject(ObjectTypeMutex, sizeof(MUTEX));
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if (!m) return STATUS_NO_MEMORY;
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m->Header.Destroy = MutexDestroy;
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m->Lock = (SPINLOCK)SPINLOCK_INIT;
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m->Owner = (struct THREAD *)0;
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LIST_INIT(&m->WaitList);
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*out = m;
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return STATUS_SUCCESS;
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}
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KSTATUS KeAcquireMutex(MUTEX* mutex) {
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if (!mutex) return STATUS_INVALID_PARAMETER;
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THREAD* self = KeCurrentThread();
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for (;;) {
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KeAcquireSpinlock(&mutex->Lock);
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if (!mutex->Owner) {
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mutex->Owner = self;
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KeReleaseSpinlock(&mutex->Lock);
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return STATUS_SUCCESS;
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}
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// Already owned - add self to wait list and block.
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ListInsertTail(&mutex->WaitList, &self->SchedulerLink);
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KeReleaseSpinlock(&mutex->Lock);
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KeBlockThread(self, &mutex->Header);
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// KeBlockThread calls KeYield; when we return here we've been
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// unblocked by KeReleaseMutex - loop back and try to own it.
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}
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}
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KSTATUS KeTryAcquireMutex(MUTEX* mutex) {
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if (!mutex) return STATUS_INVALID_PARAMETER;
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THREAD* self = KeCurrentThread();
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KeAcquireSpinlock(&mutex->Lock);
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if (!mutex->Owner) {
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mutex->Owner = self;
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KeReleaseSpinlock(&mutex->Lock);
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return STATUS_SUCCESS;
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}
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KeReleaseSpinlock(&mutex->Lock);
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return STATUS_FAILURE;
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}
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void KeReleaseMutex(MUTEX* mutex) {
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if (!mutex) return;
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KeAcquireSpinlock(&mutex->Lock);
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mutex->Owner = (struct THREAD *)0;
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// Wake the first waiter, if any.
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if (!LIST_IS_EMPTY(&mutex->WaitList)) {
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LIST_ENTRY* node = ListPopHead(&mutex->WaitList);
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THREAD* waiter = CONTAINING_RECORD(node, THREAD, SchedulerLink);
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KeReleaseSpinlock(&mutex->Lock);
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KeUnblockThread(waiter);
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return;
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}
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KeReleaseSpinlock(&mutex->Lock);
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}
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