105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
// ke_dpc.c - deferred procedure calls
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#include <ke_dpc.h>
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#include <ke_irql.h>
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#include <ke_debug.h>
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#include <intrin.h>
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static LIST_ENTRY gDpcQueue;
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static SPINLOCK gDpcLock;
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static volatile long gDpcInitialized = 0;
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static volatile long gDpcActive = 0;
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void KeInitializeDpcSystem(void) {
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LIST_INIT(&gDpcQueue);
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gDpcLock = (SPINLOCK)SPINLOCK_INIT;
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gDpcActive = 0;
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gDpcInitialized = 1;
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}
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static void KiEnsureDpcInitialized(void) {
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if (gDpcInitialized)
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return;
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// Single-CPU bring-up path: this is only a safety net for early callers.
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KeInitializeDpcSystem();
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}
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__declspec(dllexport) void KeInitializeDpc(KDPC* dpc,
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KDEFERRED_ROUTINE routine,
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void* context) {
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if (!dpc)
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return;
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LIST_INIT(&dpc->Link);
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dpc->Routine = routine;
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dpc->Context = context;
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dpc->SystemArgument1 = (void*)0;
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dpc->SystemArgument2 = (void*)0;
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dpc->Inserted = 0;
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}
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__declspec(dllexport) bool KeInsertQueueDpc(KDPC* dpc,
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void* systemArgument1,
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void* systemArgument2) {
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if (!dpc || !dpc->Routine)
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return false;
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KiEnsureDpcInitialized();
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// Coalesce repeated inserts of the same KDPC. The first insert owns the
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// argument pair until the DPC is popped by the dispatcher.
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if (_InterlockedCompareExchange(&dpc->Inserted, 1, 0) != 0)
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return false;
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dpc->SystemArgument1 = systemArgument1;
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dpc->SystemArgument2 = systemArgument2;
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uintptr_t flags = KeAcquireSpinlock(&gDpcLock);
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ListInsertTail(&gDpcQueue, &dpc->Link);
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KeReleaseSpinlock(&gDpcLock, flags);
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return true;
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}
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void KiDrainDpcQueue(void) {
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if (!gDpcInitialized)
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return;
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// Never run DPC routines above DISPATCH_LEVEL. If a future nested IRQ path
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// reaches here at DIRQL, leave the work pending for the outermost exit.
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if (KeGetCurrentIrql() > DISPATCH_LEVEL)
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return;
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if (_InterlockedCompareExchange(&gDpcActive, 1, 0) != 0)
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return;
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KIRQL oldIrql = KeGetCurrentIrql();
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if (oldIrql < DISPATCH_LEVEL)
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KeRaiseIrql(DISPATCH_LEVEL);
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for (;;) {
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uintptr_t flags = KeAcquireSpinlock(&gDpcLock);
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LIST_ENTRY* node = ListPopHead(&gDpcQueue);
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if (!node) {
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KeReleaseSpinlock(&gDpcLock, flags);
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break;
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}
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KDPC* dpc = CONTAINING_RECORD(node, KDPC, Link);
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void* arg1 = dpc->SystemArgument1;
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void* arg2 = dpc->SystemArgument2;
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dpc->SystemArgument1 = (void*)0;
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dpc->SystemArgument2 = (void*)0;
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dpc->Inserted = 0;
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KeReleaseSpinlock(&gDpcLock, flags);
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KeAssertIrql(DISPATCH_LEVEL);
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dpc->Routine(dpc, dpc->Context, arg1, arg2);
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KeAssertIrql(DISPATCH_LEVEL);
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}
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gDpcActive = 0;
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if (oldIrql < DISPATCH_LEVEL)
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KeLowerIrql(oldIrql);
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}
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