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InterlockedPushEntrySList() and InterlockedPopEntrySList() shouldn't serialize access to the list with semaphores

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svn path=/trunk/; revision=13709
This commit is contained in:
Thomas Bluemel 2005-02-22 01:07:41 +00:00
parent 7e242c624b
commit d2417ffe5a
4 changed files with 70 additions and 8 deletions
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49
reactos/ntoskrnl/ex/list.c
View file

@ -16,8 +16,6 @@
#define NDEBUG
#include <internal/debug.h>
static KSPIN_LOCK ExpGlobalListLock = { 0, };
/* FUNCTIONS *************************************************************/
/*
@ -446,8 +444,31 @@ PSLIST_ENTRY
FASTCALL
InterlockedPopEntrySList(IN PSLIST_HEADER ListHead)
{
return (PSLIST_ENTRY) ExInterlockedPopEntrySList(ListHead,
&ExpGlobalListLock);
SLIST_HEADER newslh, oldslh;
PSLIST_ENTRY le;
do
{
oldslh = *ListHead;
le = oldslh.Next.Next;
if(le == NULL)
{
/* nothing to do */
return NULL;
}
newslh.Sequence = oldslh.Sequence + 1;
newslh.Depth = oldslh.Depth - 1;
newslh.Next.Next = MmSafeReadPtr(&le->Next);
if(newslh.Next.Next == NULL)
{
/* try again */
continue;
}
} while(ExfInterlockedCompareExchange64(&ListHead->Alignment,
&newslh.Alignment,
&oldslh.Alignment) != oldslh.Alignment);
return le;
}
@ -457,11 +478,23 @@ InterlockedPopEntrySList(IN PSLIST_HEADER ListHead)
PSLIST_ENTRY
FASTCALL
InterlockedPushEntrySList(IN PSLIST_HEADER ListHead,
IN PSLIST_ENTRY ListEntry)
IN PSLIST_ENTRY ListEntry)
{
return (PSLIST_ENTRY) ExInterlockedPushEntrySList(ListHead,
ListEntry,
&ExpGlobalListLock);
SLIST_HEADER newslh, oldslh;
newslh.Next.Next = ListEntry;
do
{
oldslh = *ListHead;
newslh.Depth = oldslh.Depth + 1;
newslh.Sequence = oldslh.Sequence + 1;
ListEntry->Next = oldslh.Next.Next;
} while(ExfInterlockedCompareExchange64(&ListHead->Alignment,
&newslh.Alignment,
&oldslh.Alignment) != oldslh.Alignment);
return oldslh.Next.Next;
}
/* EOF */

2
reactos/ntoskrnl/include/internal/mm.h
View file

@ -563,6 +563,8 @@ NTSTATUS MmSafeCopyFromUser(PVOID Dest, const VOID *Src, ULONG Count);
NTSTATUS MmSafeCopyToUser(PVOID Dest, const VOID *Src, ULONG Count);
PVOID FASTCALL MmSafeReadPtr(PVOID Source);
/* pageop.c ******************************************************************/
VOID

16
reactos/ntoskrnl/mm/i386/memsafe.s
View file

@ -4,6 +4,9 @@
.globl _MmSafeCopyToUser
.globl _MmSafeCopyToUserUnsafeStart
.globl _MmSafeCopyToUserRestart
.globl @MmSafeReadPtr@4
.globl _MmSafeReadPtrStart
.globl _MmSafeReadPtrEnd
/*
* NTSTATUS MmSafeCopyFromUser(PVOID Dest, PVOID Src,
@ -83,3 +86,16 @@ _MmSafeCopyToUserRestart:
popl %ebp
ret
/*****************************************************************************/
/*
* PVOID FASTCALL MmSafeReadPtr(PVOID Source)
*/
@MmSafeReadPtr@4:
_MmSafeReadPtrStart:
/*
* If we incur a pagefault, eax will be set NULL
*/
movl (%ecx),%eax
_MmSafeReadPtrEnd:
ret

11
reactos/ntoskrnl/mm/i386/pfault.c
View file

@ -20,6 +20,8 @@ extern VOID MmSafeCopyFromUserUnsafeStart(VOID);
extern VOID MmSafeCopyFromUserRestart(VOID);
extern VOID MmSafeCopyToUserUnsafeStart(VOID);
extern VOID MmSafeCopyToUserRestart(VOID);
extern VOID MmSafeReadPtrStart(VOID);
extern VOID MmSafeReadPtrEnd(VOID);
extern ULONG MmGlobalKernelPageDirectory[1024];
@ -90,5 +92,14 @@ NTSTATUS MmPageFault(ULONG Cs,
(*Eax) = STATUS_ACCESS_VIOLATION;
return(STATUS_SUCCESS);
}
if (!NT_SUCCESS(Status) && (Mode == KernelMode) &&
((*Eip) >= (ULONG_PTR)MmSafeReadPtrStart) &&
((*Eip) <= (ULONG_PTR)MmSafeReadPtrEnd))
{
(*Eip) = (ULONG_PTR)MmSafeReadPtrEnd;
(*Eax) = 0;
return(STATUS_SUCCESS);
}
return(Status);
}