windows-nt/Source/XPSP1/NT/base/ntos/ke/timerobj.c
2020-09-26 16:20:57 +08:00

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/*++
Copyright (c) 1989 Microsoft Corporation
Module Name:
timerobj.c
Abstract:
This module implements the kernel timer object. Functions are
provided to initialize, read, set, and cancel timer objects.
Author:
David N. Cutler (davec) 2-Mar-1989
Environment:
Kernel mode only.
Revision History:
--*/
#include "ki.h"
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGELK, KeQueryTimerDueTime)
#endif
//
// The following assert macro is used to check that an input timer is
// really a ktimer and not something else, like deallocated pool.
//
#define ASSERT_TIMER(E) { \
ASSERT(((E)->Header.Type == TimerNotificationObject) || \
((E)->Header.Type == TimerSynchronizationObject)); \
}
VOID
KeInitializeTimer (
IN PKTIMER Timer
)
/*++
Routine Description:
This function initializes a kernel timer object.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
Return Value:
None.
--*/
{
//
// Initialize extended timer object with a type of notification and a
// period of zero.
//
KeInitializeTimerEx(Timer, NotificationTimer);
return;
}
VOID
KeInitializeTimerEx (
IN PKTIMER Timer,
IN TIMER_TYPE Type
)
/*++
Routine Description:
This function initializes an extended kernel timer object.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
Type - Supplies the type of timer object; NotificationTimer or
SynchronizationTimer;
Return Value:
None.
--*/
{
//
// Initialize standard dispatcher object header and set initial
// state of timer.
//
Timer->Header.Type = TimerNotificationObject + Type;
Timer->Header.Inserted = FALSE;
Timer->Header.Size = sizeof(KTIMER) / sizeof(LONG);
Timer->Header.SignalState = FALSE;
#if DBG
Timer->TimerListEntry.Flink = NULL;
Timer->TimerListEntry.Blink = NULL;
#endif
InitializeListHead(&Timer->Header.WaitListHead);
Timer->DueTime.QuadPart = 0;
Timer->Period = 0;
return;
}
VOID
KeClearTimer (
IN PKTIMER Timer
)
/*++
Routine Description:
This function clears the signal state of an timer object.
Arguments:
Event - Supplies a pointer to a dispatcher object of type timer.
Return Value:
None.
--*/
{
ASSERT_TIMER(Timer);
//
// Clear signal state of timer object.
//
Timer->Header.SignalState = 0;
return;
}
BOOLEAN
KeCancelTimer (
IN PKTIMER Timer
)
/*++
Routine Description:
This function cancels a timer that was previously set to expire at
a specified time. If the timer is not currently set, then no operation
is performed. Canceling a timer does not set the state of the timer to
Signaled.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
Return Value:
A boolean value of TRUE is returned if the the specified timer was
currently set. Else a value of FALSE is returned.
--*/
{
BOOLEAN Inserted;
KIRQL OldIrql;
ASSERT_TIMER(Timer);
ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);
//
// Raise IRQL to dispatcher level, lock the dispatcher database, and
// capture the timer inserted status. If the timer is currently set,
// then remove it from the timer list.
//
KiLockDispatcherDatabase(&OldIrql);
Inserted = Timer->Header.Inserted;
if (Inserted != FALSE) {
KiRemoveTreeTimer(Timer);
}
//
// Unlock the dispatcher database, lower IRQL to its previous value, and
// return boolean value that signifies whether the timer was set of not.
//
KiUnlockDispatcherDatabase(OldIrql);
return Inserted;
}
BOOLEAN
KeReadStateTimer (
IN PKTIMER Timer
)
/*++
Routine Description:
This function reads the current signal state of a timer object.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
Return Value:
The current signal state of the timer object.
--*/
{
ASSERT_TIMER(Timer);
//
// Return current signal state of timer object.
//
return (BOOLEAN)Timer->Header.SignalState;
}
BOOLEAN
KeSetTimer (
IN PKTIMER Timer,
IN LARGE_INTEGER DueTime,
IN PKDPC Dpc OPTIONAL
)
/*++
Routine Description:
This function sets a timer to expire at a specified time. If the timer is
already set, then it is implicitly canceled before it is set to expire at
the specified time. Setting a timer causes its due time to be computed,
its state to be set to Not-Signaled, and the timer object itself to be
inserted in the timer list.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
DueTime - Supplies an absolute or relative time at which the timer
is to expire.
Dpc - Supplies an optional pointer to a control object of type DPC.
Return Value:
A boolean value of TRUE is returned if the the specified timer was
currently set. Else a value of FALSE is returned.
--*/
{
//
// Set the timer with a period of zero.
//
return KeSetTimerEx(Timer, DueTime, 0, Dpc);
}
BOOLEAN
KeSetTimerEx (
IN PKTIMER Timer,
IN LARGE_INTEGER DueTime,
IN LONG Period OPTIONAL,
IN PKDPC Dpc OPTIONAL
)
/*++
Routine Description:
This function sets a timer to expire at a specified time. If the timer is
already set, then it is implicitly canceled before it is set to expire at
the specified time. Setting a timer causes its due time to be computed,
its state to be set to Not-Signaled, and the timer object itself to be
inserted in the timer list.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
DueTime - Supplies an absolute or relative time at which the timer
is to expire.
Period - Supplies an optional period for the timer in milliseconds.
Dpc - Supplies an optional pointer to a control object of type DPC.
Return Value:
A boolean value of TRUE is returned if the the specified timer was
currently set. Else a value of FALSE is returned.
--*/
{
BOOLEAN Inserted;
LARGE_INTEGER Interval;
KIRQL OldIrql;
LARGE_INTEGER SystemTime;
ASSERT_TIMER(Timer);
ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);
//
// Raise IRQL to dispatcher level and lock dispatcher database.
//
KiLockDispatcherDatabase(&OldIrql);
//
// Capture the timer inserted status and if the timer is currently
// set, then remove it from the timer list.
//
Inserted = Timer->Header.Inserted;
if (Inserted != FALSE) {
KiRemoveTreeTimer(Timer);
}
//
// Clear the signal state, set the period, set the DPC address, and
// insert the timer in the timer tree. If the timer is not inserted
// in the timer tree, then it has already expired and as many waiters
// as possible should be continued, and a DPC, if specified should be
// queued.
//
// N.B. The signal state must be cleared in case the period is not
// zero.
//
Timer->Header.SignalState = FALSE;
Timer->Dpc = Dpc;
Timer->Period = Period;
if (KiInsertTreeTimer((PRKTIMER)Timer, DueTime) == FALSE) {
if (IsListEmpty(&Timer->Header.WaitListHead) == FALSE) {
KiWaitTest(Timer, TIMER_EXPIRE_INCREMENT);
}
//
// If a DPC is specfied, then call the DPC routine.
//
if (Dpc != NULL) {
KiQuerySystemTime(&SystemTime);
KeInsertQueueDpc(Timer->Dpc,
ULongToPtr(SystemTime.LowPart),
ULongToPtr(SystemTime.HighPart));
}
//
// If the timer is periodic, then compute the next interval time
// and reinsert the timer in the timer tree.
//
// N.B. Even though the timer insertion is relative, it can still
// fail if the period of the timer elapses in between computing
// the time and inserting the timer. If this happens, then the
// the insertion is retried.
//
if (Period != 0) {
Interval.QuadPart = Int32x32To64(Timer->Period, - 10 * 1000);
do {
} while (KiInsertTreeTimer(Timer, Interval) == FALSE);
}
}
//
// Unlock the dispatcher database and lower IRQL to its previous
// value.
//
KiUnlockDispatcherDatabase(OldIrql);
//
// Return boolean value that signifies whether the timer was set of
// not.
//
return Inserted;
}
ULONGLONG
KeQueryTimerDueTime (
IN PKTIMER Timer
)
/*++
Routine Description:
This function returns the InterruptTime at which the timer is
pending. 0 is returned if the timer is not pending.
N.B. This function may only be called by the system sleep code.
Arguments:
Timer - Supplies a pointer to a dispatcher object of type timer.
Return Value:
Returns the amount of time remaining on the timer, or 0 if the
timer is not pending.
--*/
{
KIRQL OldIrql;
LARGE_INTEGER InterruptTime;
ULONGLONG DueTime;
ASSERT_TIMER(Timer);
//
// Raise IRQL to dispatcher level and lock dispatcher database.
//
KiLockDispatcherDatabase(&OldIrql);
//
// If the timer is currently pending, compute its due time
//
DueTime = 0;
if (Timer->Header.Inserted) {
DueTime = Timer->DueTime.QuadPart;
}
//
// Unlock the dispatcher database and lower IRQL to its previous
// value, and return the due time
//
KiUnlockDispatcherDatabase(OldIrql);
return DueTime;
}
VOID
KeCheckForTimer(
IN PVOID BlockStart,
IN SIZE_T BlockSize
)
/*++
Routine Description:
This function is used for debugging by checking all timers
to see if any is in the memory block passed. If so, the
system bugchecks.
Arguments:
BlockStart - Base address to check for timer.
BlockSize - Size (in bytes) to check in the memory block.
Return Value:
None.
--*/
{
ULONG Index;
PLIST_ENTRY ListHead;
PLIST_ENTRY NextEntry;
KIRQL OldIrql;
PKTIMER Timer;
PUCHAR Address;
PUCHAR Start;
PUCHAR End;
//
// Compute the ending memory location.
//
Start = (PUCHAR)BlockStart;
End = Start + BlockSize;
//
// Raise IRQL to dispatcher level and lock dispatcher database.
//
KiLockDispatcherDatabase(&OldIrql);
//
// Run the entire timer database and check for any timers in
// the memory block
//
Index = 0;
do {
ListHead = &KiTimerTableListHead[Index];
NextEntry = ListHead->Flink;
while (NextEntry != ListHead) {
Timer = CONTAINING_RECORD(NextEntry, KTIMER, TimerListEntry);
Address = (PUCHAR)Timer;
NextEntry = NextEntry->Flink;
//
// Check this timer object is not in the range.
// In each of the following, we check that the object
// does not overlap the range, for example, if the timer
// object (in this first check), starts one dword before
// the range being checked, we have an overlap and should
// stop.
//
if ((Address > (Start - sizeof(KTIMER))) &&
(Address < End)) {
KeBugCheckEx(TIMER_OR_DPC_INVALID,
0x0,
(ULONG_PTR)Address,
(ULONG_PTR)Start,
(ULONG_PTR)End);
}
if (Timer->Dpc) {
//
// Check the timer's DPC object isn't in the range.
//
Address = (PUCHAR)Timer->Dpc;
if ((Address > (Start - sizeof(KDPC))) &&
(Address < End)) {
KeBugCheckEx(TIMER_OR_DPC_INVALID,
0x1,
(ULONG_PTR)Address,
(ULONG_PTR)Start,
(ULONG_PTR)End);
}
//
// Check the timer's DPC routine is not in the range.
//
Address = (PUCHAR)Timer->Dpc->DeferredRoutine;
if (Address >= Start && Address < End) {
KeBugCheckEx(TIMER_OR_DPC_INVALID,
0x2,
(ULONG_PTR)Address,
(ULONG_PTR)Start,
(ULONG_PTR)End);
}
}
}
Index += 1;
} while(Index < TIMER_TABLE_SIZE);
//
// Unlock the dispatcher database and lower IRQL to its previous value
//
KiUnlockDispatcherDatabase(OldIrql);
}