117 lines
1.9 KiB
C
117 lines
1.9 KiB
C
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/*++
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Copyright (c) 2000 Microsoft Corporation
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Module Name:
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mpspin.c
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Abstract:
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This module implements the hal high level lock manipulation routines.
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Author:
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Forrest Foltz (forrestf) 1-Dec-2000
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Environment:
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Kernel mode only.
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Revision History:
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--*/
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#include "halcmn.h"
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ULONG
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HalpAcquireHighLevelLock (
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IN PKSPIN_LOCK SpinLock
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)
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/*++
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Routine Description:
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Acquires a spinlock with interrupts disabled.
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Arguments:
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SpinLock - Supplies a pointer to a kernel spin lock.
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Return Value:
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Returns the state of the EFLAGS register.
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--*/
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{
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ULONG flags;
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//
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// Remember the state of the processor flags
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//
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flags = HalpGetProcessorFlags();
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while (TRUE) {
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//
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// Disable interrupts and attempt to take the spinlock, exiting
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// the loop if it was available.
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//
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_disable();
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if (KeTryToAcquireSpinLockAtDpcLevel(SpinLock) != FALSE) {
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break;
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}
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//
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// The spinlock was not available. Restore the state of the
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// interrupt flag and spin, waiting for it to become available.
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//
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HalpRestoreInterrupts(flags);
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while (KeTestSpinLock(SpinLock) == FALSE) {
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NOTHING;
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}
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}
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return flags;
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}
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VOID
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HalpReleaseHighLevelLock (
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IN PKSPIN_LOCK SpinLock,
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IN ULONG Flags
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)
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/*++
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Routine Description:
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This function releases a kernel spin lock that was taken by
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HalpAcquireHighLevelLock() and lowers to the new irql.
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Arguments:
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SpinLock - Supplies a pointer to a kernel spin lock.
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Flags - The contents of the EFLAGS register when the
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lock was taken.
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Return Value:
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None.
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--*/
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{
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//
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// Interrupts at this point are disabled. Release the spinlock and
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// enable interrupts if they were enabled when the lock was taken.
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//
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KeReleaseSpinLockFromDpcLevel(SpinLock);
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HalpRestoreInterrupts(Flags);
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}
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