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reactos/ntoskrnl/ex/rundown.c

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/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS Kernel
* FILE: ntoskrnl/ex/rundown.c
* PURPOSE: Rundown and Cache-Aware Rundown Protection
* PROGRAMMERS: Alex Ionescu (alex@relsoft.net)
* Thomas Weidenmueller
* Pierre Schweitzer
*/
/* INCLUDES *****************************************************************/
#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>
/* FUNCTIONS *****************************************************************/
/*++
* @name ExfAcquireRundownProtection
* @implemented NT5.1
*
* The ExfAcquireRundownProtection routine acquires rundown protection for
* the specified descriptor.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @return TRUE if access to the protected structure was granted, FALSE otherwise.
*
* @remarks Callers of ExfAcquireRundownProtection can be running at any IRQL.
*
*--*/
BOOLEAN
FASTCALL
ExfAcquireRundownProtection(IN PEX_RUNDOWN_REF RunRef)
{
ULONG_PTR Value = RunRef->Count, NewValue;
/* Loop until successfully incremented the counter */
for (;;)
{
/* Make sure a rundown is not active */
if (Value & EX_RUNDOWN_ACTIVE) return FALSE;
/* Add a reference */
NewValue = Value + EX_RUNDOWN_COUNT_INC;
/* Change the value */
NewValue = ExpChangeRundown(RunRef, NewValue, Value);
if (NewValue == Value) return TRUE;
/* Update it */
Value = NewValue;
}
}
/*++
* @name ExfAcquireRundownProtectionEx
* @implemented NT5.2
*
* The ExfAcquireRundownProtectionEx routine acquires multiple rundown
* protection references for the specified descriptor.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @param Count
* Number of times to reference the descriptor.
*
* @return TRUE if access to the protected structure was granted, FALSE otherwise.
*
* @remarks Callers of ExfAcquireRundownProtectionEx can be running at any IRQL.
*
*--*/
BOOLEAN
FASTCALL
ExfAcquireRundownProtectionEx(IN PEX_RUNDOWN_REF RunRef,
IN ULONG Count)
{
ULONG_PTR Value = RunRef->Count, NewValue;
/* Loop until successfully incremented the counter */
for (;;)
{
/* Make sure a rundown is not active */
if (Value & EX_RUNDOWN_ACTIVE) return FALSE;
/* Add references */
NewValue = Value + EX_RUNDOWN_COUNT_INC * Count;
/* Change the value */
NewValue = ExpChangeRundown(RunRef, NewValue, Value);
if (NewValue == Value) return TRUE;
/* Update the value */
Value = NewValue;
}
}
/*++
* @name ExfInitializeRundownProtection
* @implemented NT5.1
*
* The ExfInitializeRundownProtection routine initializes a rundown
* protection descriptor.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @return None.
*
* @remarks Callers of ExfInitializeRundownProtection can be running at any IRQL.
*
*--*/
VOID
FASTCALL
ExfInitializeRundownProtection(IN PEX_RUNDOWN_REF RunRef)
{
/* Set the count to zero */
RunRef->Count = 0;
}
/*++
* @name ExfReInitializeRundownProtection
* @implemented NT5.1
*
* The ExfReInitializeRundownProtection routine re-initializes a rundown
* protection descriptor.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @return None.
*
* @remarks Callers of ExfReInitializeRundownProtection can be running at any IRQL.
*
*--*/
VOID
FASTCALL
ExfReInitializeRundownProtection(IN PEX_RUNDOWN_REF RunRef)
{
PAGED_CODE();
/* Sanity check */
ASSERT((RunRef->Count & EX_RUNDOWN_ACTIVE) != 0);
/* Reset the count */
ExpSetRundown(RunRef, 0);
}
/*++
* @name ExfRundownCompleted
* @implemented NT5.1
*
* The ExfRundownCompleted routine completes the rundown of the specified
* descriptor by setting the active bit.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @return None.
*
* @remarks Callers of ExfRundownCompleted must be running at IRQL <= APC_LEVEL.
*
*--*/
VOID
FASTCALL
ExfRundownCompleted(IN PEX_RUNDOWN_REF RunRef)
{
PAGED_CODE();
/* Sanity check */
ASSERT((RunRef->Count & EX_RUNDOWN_ACTIVE) != 0);
/* Mark the counter as active */
ExpSetRundown(RunRef, EX_RUNDOWN_ACTIVE);
}
/*++
* @name ExfReleaseRundownProtection
* @implemented NT5.1
*
* The ExfReleaseRundownProtection routine releases the rundown protection
* reference for the specified descriptor.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @return None.
*
* @remarks Callers of ExfReleaseRundownProtection can be running at any IRQL.
*
*--*/
VOID
FASTCALL
ExfReleaseRundownProtection(IN PEX_RUNDOWN_REF RunRef)
{
ULONG_PTR Value = RunRef->Count, NewValue;
PEX_RUNDOWN_WAIT_BLOCK WaitBlock;
/* Loop until successfully incremented the counter */
for (;;)
{
/* Check if rundown is not active */
if (!(Value & EX_RUNDOWN_ACTIVE))
{
/* Sanity check */
ASSERT((Value >= EX_RUNDOWN_COUNT_INC) || (KeNumberProcessors > 1));
/* Get the new value */
NewValue = Value - EX_RUNDOWN_COUNT_INC;
/* Change the value */
NewValue = ExpChangeRundown(RunRef, NewValue, Value);
if (NewValue == Value) break;
/* Update value */
Value = NewValue;
}
else
{
/* Get the wait block */
WaitBlock = (PEX_RUNDOWN_WAIT_BLOCK)(Value & ~EX_RUNDOWN_ACTIVE);
ASSERT((WaitBlock->Count > 0) || (KeNumberProcessors > 1));
/* Remove the one count */
if (!InterlockedDecrementSizeT(&WaitBlock->Count))
{
/* We're down to 0 now, so signal the event */
KeSetEvent(&WaitBlock->WakeEvent, IO_NO_INCREMENT, FALSE);
}
/* We're all done */
break;
}
}
}
/*++
* @name ExfReleaseRundownProtectionEx
* @implemented NT5.2
*
* The ExfReleaseRundownProtectionEx routine releases multiple rundown
* protection references for the specified descriptor.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @param Count
* Number of times to dereference the descriptor.
*
* @return None.
*
* @remarks Callers of ExfAcquireRundownProtectionEx can be running at any IRQL.
*
*--*/
VOID
FASTCALL
ExfReleaseRundownProtectionEx(IN PEX_RUNDOWN_REF RunRef,
IN ULONG Count)
{
ULONG_PTR Value = RunRef->Count, NewValue;
PEX_RUNDOWN_WAIT_BLOCK WaitBlock;
/* Loop until successfully incremented the counter */
for (;;)
{
/* Check if rundown is not active */
if (!(Value & EX_RUNDOWN_ACTIVE))
{
/* Sanity check */
ASSERT((Value >= EX_RUNDOWN_COUNT_INC * Count) ||
(KeNumberProcessors > 1));
/* Get the new value */
NewValue = Value - EX_RUNDOWN_COUNT_INC * Count;
/* Change the value */
NewValue = ExpChangeRundown(RunRef, NewValue, Value);
if (NewValue == Value) break;
/* Update value */
Value = NewValue;
}
else
{
/* Get the wait block */
WaitBlock = (PEX_RUNDOWN_WAIT_BLOCK)(Value & ~EX_RUNDOWN_ACTIVE);
ASSERT((WaitBlock->Count >= Count) || (KeNumberProcessors > 1));
/* Remove the counts */
if (InterlockedExchangeAddSizeT(&WaitBlock->Count,
-(LONG)Count) == (LONG)Count)
{
/* We're down to 0 now, so signal the event */
KeSetEvent(&WaitBlock->WakeEvent, IO_NO_INCREMENT, FALSE);
}
/* We're all done */
break;
}
}
}
/*++
* @name ExfWaitForRundownProtectionRelease
* @implemented NT5.1
*
* The ExfWaitForRundownProtectionRelease routine waits until the specified
* rundown descriptor has been released.
*
* @param RunRef
* Pointer to a rundown reference descriptor.
*
* @return None.
*
* @remarks Callers of ExfWaitForRundownProtectionRelease must be running
* at IRQL <= APC_LEVEL.
*
*--*/
VOID
FASTCALL
ExfWaitForRundownProtectionRelease(IN PEX_RUNDOWN_REF RunRef)
{
ULONG_PTR Value, Count, NewValue;
EX_RUNDOWN_WAIT_BLOCK WaitBlock;
PEX_RUNDOWN_WAIT_BLOCK WaitBlockPointer;
PKEVENT Event;
PAGED_CODE();
/* Set the active bit */
Value = ExpChangeRundown(RunRef, EX_RUNDOWN_ACTIVE, 0);
if ((Value == 0) || (Value == EX_RUNDOWN_ACTIVE)) return;
/* No event for now */
Event = NULL;
WaitBlockPointer = (PEX_RUNDOWN_WAIT_BLOCK)((ULONG_PTR)&WaitBlock |
EX_RUNDOWN_ACTIVE);
/* Start waitblock set loop */
for (;;)
{
/* Save the count */
Count = Value >> EX_RUNDOWN_COUNT_SHIFT;
/* If the count is over one and we don't have en event yet, create it */
if ((Count) && !(Event))
{
/* Initialize the event */
KeInitializeEvent(&WaitBlock.WakeEvent,
SynchronizationEvent,
FALSE);
/* Set the pointer */
Event = &WaitBlock.WakeEvent;
}
/* Set the count */
WaitBlock.Count = Count;
/* Now set the pointer */
NewValue = ExpChangeRundown(RunRef, (ULONG_PTR)WaitBlockPointer, Value);
if (NewValue == Value) break;
/* Loop again */
Value = NewValue;
ASSERT((Value & EX_RUNDOWN_ACTIVE) == 0);
}
/* If the count was 0, we're done */
if (!Count) return;
/* Wait for whoever needs to release to notify us */
KeWaitForSingleObject(Event, Executive, KernelMode, FALSE, NULL);
ASSERT(WaitBlock.Count == 0);
}
/*
* @implemented NT5.2
*/
BOOLEAN
FASTCALL
ExfAcquireRundownProtectionCacheAware(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware)
{
PEX_RUNDOWN_REF RunRef;
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, KeGetCurrentProcessorNumber());
return _ExAcquireRundownProtection(RunRef);
}
/*
* @implemented NT5.2
*/
BOOLEAN
FASTCALL
ExfAcquireRundownProtectionCacheAwareEx(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware,
IN ULONG Count)
{
PEX_RUNDOWN_REF RunRef;
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, KeGetCurrentProcessorNumber());
return ExfAcquireRundownProtectionEx(RunRef, Count);
}
/*
* @implemented NT5.2
*/
VOID
FASTCALL
ExfReleaseRundownProtectionCacheAware(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware)
{
PEX_RUNDOWN_REF RunRef;
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, KeGetCurrentProcessorNumber());
_ExReleaseRundownProtection(RunRef);
}
/*
* @implemented NT5.2
*/
VOID
FASTCALL
ExfReleaseRundownProtectionCacheAwareEx(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware,
IN ULONG Count)
{
PEX_RUNDOWN_REF RunRef;
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, KeGetCurrentProcessorNumber());
ExfReleaseRundownProtectionEx(RunRef, Count);
}
/*
* @implemented NT5.2
*/
VOID
FASTCALL
ExfWaitForRundownProtectionReleaseCacheAware(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware)
{
PEX_RUNDOWN_REF RunRef;
EX_RUNDOWN_WAIT_BLOCK WaitBlock;
PEX_RUNDOWN_WAIT_BLOCK WaitBlockPointer;
ULONG_PTR ProcCount, Current, Value, OldValue, TotalCount;
ProcCount = RunRefCacheAware->Number;
/* No proc, nothing to do */
if (ProcCount == 0)
{
return;
}
TotalCount = 0;
WaitBlock.Count = 0;
WaitBlockPointer = (PEX_RUNDOWN_WAIT_BLOCK)((ULONG_PTR)&WaitBlock |
EX_RUNDOWN_ACTIVE);
/* We will check all our runrefs */
for (Current = 0; Current < ProcCount; ++Current)
{
/* Get the runref for the proc */
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, Current);
/* Loop for setting the wait block */
do
{
Value = RunRef->Count;
ASSERT((Value & EX_RUNDOWN_ACTIVE) == 0);
/* Remove old value and set our waitblock instead */
OldValue = ExpChangeRundown(RunRef, WaitBlockPointer, Value);
if (OldValue == Value)
{
break;
}
Value = OldValue;
}
while (TRUE);
/* Count the deleted values */
TotalCount += Value;
}
/* Sanity check: we didn't overflow */
ASSERT((LONG_PTR)TotalCount >= 0);
if (TotalCount != 0)
{
/* Init the waitblock event */
KeInitializeEvent(&WaitBlock.WakeEvent,
SynchronizationEvent,
FALSE);
/* Do we have to wait? If so, go ahead! */
if (InterlockedExchangeAddSizeT(&WaitBlock.Count,
(LONG_PTR)TotalCount >> EX_RUNDOWN_COUNT_SHIFT) ==
-(LONG_PTR)(TotalCount >> EX_RUNDOWN_COUNT_SHIFT))
{
KeWaitForSingleObject(&WaitBlock.WakeEvent, Executive, KernelMode, FALSE, NULL);
}
}
}
/*
* @implemented NT5.2
*/
VOID
FASTCALL
ExfRundownCompletedCacheAware(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware)
{
PEX_RUNDOWN_REF RunRef;
ULONG ProcCount, Current;
ProcCount = RunRefCacheAware->Number;
/* No proc, nothing to do */
if (ProcCount == 0)
{
return;
}
/* We will mark all our runrefs active */
for (Current = 0; Current < ProcCount; ++Current)
{
/* Get the runref for the proc */
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, Current);
ASSERT((RunRef->Count & EX_RUNDOWN_ACTIVE) != 0);
ExpSetRundown(RunRef, EX_RUNDOWN_ACTIVE);
}
}
/*
* @implemented NT5.2
*/
VOID
FASTCALL
ExfReInitializeRundownProtectionCacheAware(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware)
{
PEX_RUNDOWN_REF RunRef;
ULONG ProcCount, Current;
ProcCount = RunRefCacheAware->Number;
/* No proc, nothing to do */
if (ProcCount == 0)
{
return;
}
/* We will mark all our runrefs inactive */
for (Current = 0; Current < ProcCount; ++Current)
{
/* Get the runref for the proc */
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, Current);
ASSERT((RunRef->Count & EX_RUNDOWN_ACTIVE) != 0);
ExpSetRundown(RunRef, 0);
}
}
/*
* @implemented NT5.2
*/
PEX_RUNDOWN_REF_CACHE_AWARE
NTAPI
ExAllocateCacheAwareRundownProtection(IN POOL_TYPE PoolType,
IN ULONG Tag)
{
PEX_RUNDOWN_REF RunRef;
PVOID PoolToFree, RunRefs;
ULONG RunRefSize, Count, Align;
PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware;
PAGED_CODE();
/* Allocate the master structure */
RunRefCacheAware = ExAllocatePoolWithTag(PoolType, sizeof(EX_RUNDOWN_REF_CACHE_AWARE), Tag);
if (RunRefCacheAware == NULL)
{
return NULL;
}
/* Compute the size of each runref */
RunRefCacheAware->Number = KeNumberProcessors;
if (KeNumberProcessors <= 1)
{
RunRefSize = sizeof(EX_RUNDOWN_REF);
}
else
{
Align = KeGetRecommendedSharedDataAlignment();
RunRefSize = Align;
ASSERT((RunRefSize & (RunRefSize - 1)) == 0);
}
/* It must at least hold a EX_RUNDOWN_REF structure */
ASSERT(sizeof(EX_RUNDOWN_REF) <= RunRefSize);
RunRefCacheAware->RunRefSize = RunRefSize;
/* Allocate our runref pool */
PoolToFree = ExAllocatePoolWithTag(PoolType, RunRefSize * RunRefCacheAware->Number, Tag);
if (PoolToFree == NULL)
{
ExFreePoolWithTag(RunRefCacheAware, Tag);
return NULL;
}
/* On SMP, check for alignment */
if (RunRefCacheAware->Number > 1 && (ULONG_PTR)PoolToFree & (Align - 1))
{
/* Not properly aligned, do it again! */
ExFreePoolWithTag(PoolToFree, Tag);
/* Allocate a bigger buffer to be able to align properly */
PoolToFree = ExAllocatePoolWithTag(PoolType, RunRefSize * (RunRefCacheAware->Number + 1), Tag);
if (PoolToFree == NULL)
{
ExFreePoolWithTag(RunRefCacheAware, Tag);
return NULL;
}
RunRefs = (PVOID)ALIGN_UP_BY(PoolToFree, Align);
}
else
{
RunRefs = PoolToFree;
}
RunRefCacheAware->RunRefs = RunRefs;
RunRefCacheAware->PoolToFree = PoolToFree;
/* And initialize runref */
if (RunRefCacheAware->Number != 0)
{
for (Count = 0; Count < RunRefCacheAware->Number; ++Count)
{
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, Count);
_ExInitializeRundownProtection(RunRef);
}
}
return RunRefCacheAware;
}
/*
* @implemented NT5.2
*/
VOID
NTAPI
ExFreeCacheAwareRundownProtection(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware)
{
PAGED_CODE();
/*
* This is to be called for RunRefCacheAware that were allocated with
* ExAllocateCacheAwareRundownProtection and not for user-allocated
* ones
*/
ASSERT(RunRefCacheAware->PoolToFree != (PVOID)0xBADCA11);
/* We don't know the tag that as used for allocation */
ExFreePoolWithTag(RunRefCacheAware->PoolToFree, 0);
ExFreePoolWithTag(RunRefCacheAware, 0);
}
/*
* @implemented NT5.2
*/
VOID
NTAPI
ExInitializeRundownProtectionCacheAware(IN PEX_RUNDOWN_REF_CACHE_AWARE RunRefCacheAware,
IN SIZE_T Size)
{
PVOID Pool;
PEX_RUNDOWN_REF RunRef;
ULONG Count, RunRefSize, Align;
PAGED_CODE();
/* Get the user allocate pool for runrefs */
Pool = (PVOID)((ULONG_PTR)RunRefCacheAware + sizeof(EX_RUNDOWN_REF_CACHE_AWARE));
/* By default a runref is structure-sized */
RunRefSize = sizeof(EX_RUNDOWN_REF);
/*
* If we just have enough room for a single runref, deduce were on a single
* processor machine
*/
if (Size == sizeof(EX_RUNDOWN_REF_CACHE_AWARE) + sizeof(EX_RUNDOWN_REF))
{
Count = 1;
}
else
{
/* Get alignment constraint */
Align = KeGetRecommendedSharedDataAlignment();
/* How many runrefs given the alignment? */
RunRefSize = Align;
Count = ((Size - sizeof(EX_RUNDOWN_REF_CACHE_AWARE)) / Align) - 1;
Pool = (PVOID)ALIGN_UP_BY(Pool, Align);
}
/* Initialize the structure */
RunRefCacheAware->RunRefs = Pool;
RunRefCacheAware->RunRefSize = RunRefSize;
RunRefCacheAware->Number = Count;
/* There is no allocated pool! */
RunRefCacheAware->PoolToFree = (PVOID)0xBADCA11u;
/* Initialize runref */
if (RunRefCacheAware->Number != 0)
{
for (Count = 0; Count < RunRefCacheAware->Number; ++Count)
{
RunRef = ExGetRunRefForGivenProcessor(RunRefCacheAware, Count);
_ExInitializeRundownProtection(RunRef);
}
}
}
/*
* @implemented NT5.2
*/
SIZE_T
NTAPI
ExSizeOfRundownProtectionCacheAware(VOID)
{
SIZE_T Size;
PAGED_CODE();
/* Compute the needed size for runrefs */
if (KeNumberProcessors <= 1)
{
Size = sizeof(EX_RUNDOWN_REF);
}
else
{
/* We +1, to have enough room for alignment */
Size = (KeNumberProcessors + 1) * KeGetRecommendedSharedDataAlignment();
}
/* Return total size (master structure and runrefs) */
return Size + sizeof(EX_RUNDOWN_REF_CACHE_AWARE);
}
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