Intravision/reactos
1
0
Fork 0
mirror of https://github.com/reactos/reactos.git synced 2025-04-28 01:11:35 +00:00
Code Issues Projects Releases Packages Wiki Activity

- Create a double-mapping PTE for the shared user data region and fault it in whenever a process touches that address.

Browse source 
- Remove the old hack which used the PCR's page frame number to create a fake PTE each time to reference it, basing on the fact that the shared user data region was on the same page as the PCR on certain architectures.

svn path=/trunk/; revision=42252
This commit is contained in:
ReactOS Portable Systems Group 2009-07-27 02:13:19 +00:00
parent 059da34e93
commit 3e04cabe4e
2 changed files with 34 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
reactos/ntoskrnl/mm/mmfault.c
View file

@ -150,7 +150,7 @@ MmNotPresentFault(KPROCESSOR_MODE Mode,
MEMORY_AREA* MemoryArea;
NTSTATUS Status;
BOOLEAN Locked = FromMdl;
PFN_TYPE Pfn;
extern PMMPTE MmSharedUserDataPte;
DPRINT("MmNotPresentFault(Mode %d, Address %x)\n", Mode, Address);
@ -228,14 +228,8 @@ MmNotPresentFault(KPROCESSOR_MODE Mode,
break;
case MEMORY_AREA_SHARED_DATA:
Pfn = MmGetPhysicalAddress((PVOID)PCR).LowPart >> PAGE_SHIFT;
Pfn++;
Status =
MmCreateVirtualMapping(PsGetCurrentProcess(),
(PVOID)PAGE_ROUND_DOWN(Address),
PAGE_READONLY,
&Pfn,
1);
*MiAddressToPte(USER_SHARED_DATA) = *MmSharedUserDataPte;
Status = STATUS_SUCCESS;
break;
default:

31
reactos/ntoskrnl/mm/mminit.c
View file

@ -48,6 +48,7 @@ MemType[] =
PBOOLEAN Mm64BitPhysicalAddress = FALSE;
ULONG MmReadClusterSize;
MM_STATS MmStats;
PMMPTE MmSharedUserDataPte;
PMMSUPPORT MmKernelAddressSpace;
extern KMUTANT MmSystemLoadLock;
extern ULONG MmBootImageSize;
@ -181,6 +182,11 @@ NTAPI
MmInitSystem(IN ULONG Phase,
IN PLOADER_PARAMETER_BLOCK LoaderBlock)
{
extern MMPTE HyperTemplatePte;
PMMPTE PointerPte;
MMPTE TempPte = HyperTemplatePte;
PFN_NUMBER PageFrameNumber;
if (Phase == 0)
{
/* Initialize Mm bootstrap */
@ -210,6 +216,31 @@ MmInitSystem(IN ULONG Phase,
MmInitSectionImplementation();
MmInitPagingFile();
//
// Create a PTE to double-map the shared data section. We allocate it
// from paged pool so that we can't fault when trying to touch the PTE
// itself (to map it), since paged pool addresses will already be mapped
// by the fault handler.
//
MmSharedUserDataPte = ExAllocatePoolWithTag(PagedPool,
sizeof(MMPTE),
' mM');
if (!MmSharedUserDataPte) return FALSE;
//
// Now get the PTE for shared data, and read the PFN that holds it
//
PointerPte = MiAddressToPte(KI_USER_SHARED_DATA);
ASSERT(PointerPte->u.Hard.Valid == 1);
PageFrameNumber = PFN_FROM_PTE(PointerPte);
//
// Now write a copy of it
//
TempPte.u.Hard.Owner = 1;
TempPte.u.Hard.PageFrameNumber = PageFrameNumber;
*MmSharedUserDataPte = TempPte;
/*
* Unmap low memory
*/