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Return to an old idea of MiMapPageToZeroInHyperSpace(), "fix" bug #4267.

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svn path=/trunk/; revision=40008
This commit is contained in:
Dmitry Gorbachev 2009-03-14 01:20:18 +00:00
parent 67d3295fc6
commit c9901dd8b6
1 changed files with 41 additions and 12 deletions
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53
reactos/ntoskrnl/mm/hypermap.c
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@ -14,8 +14,11 @@
/* GLOBALS ********************************************************************/
#define MI_ZEROING_PTES 255
PMMPTE MmFirstReservedMappingPte;
PMMPTE MmLastReservedMappingPte;
PMMPTE MmFirstReservedZeroingPte;
MMPTE HyperTemplatePte;
PEPROCESS HyperProcess;
KIRQL HyperIrql;
@ -40,6 +43,8 @@ MiInitHyperSpace(VOID)
MmFirstReservedMappingPte = MiAddressToPte(MI_MAPPING_RANGE_START);
MmLastReservedMappingPte = MiAddressToPte(MI_MAPPING_RANGE_END);
MmFirstReservedMappingPte->u.Hard.PageFrameNumber = MI_HYPERSPACE_PTES;
MmFirstReservedZeroingPte = MiAddressToPte(MI_ZERO_PTE);
MmFirstReservedZeroingPte->u.Hard.PageFrameNumber = MI_ZEROING_PTES;
}
PVOID
@ -134,38 +139,62 @@ MiMapPageToZeroInHyperSpace(IN PFN_NUMBER Page)
{
MMPTE TempPte;
PMMPTE PointerPte;
PFN_NUMBER Offset;
PVOID Address;
//
// Never accept page 0
//
ASSERT(Page != 0);
//
// Build the PTE
//
TempPte = HyperTemplatePte;
TempPte.u.Hard.PageFrameNumber = Page;
//
// Get the Zero PTE and its address
// Pick the first zeroing PTE
//
PointerPte = MiAddressToPte(MI_ZERO_PTE);
Address = (PVOID)((ULONG_PTR)PointerPte << 10);
PointerPte = MmFirstReservedZeroingPte;
//
// Invalidate the old address
// Now get the first free PTE
//
__invlpg(Address);
Offset = PFN_FROM_PTE(PointerPte);
if (!Offset)
{
//
// Reset the PTEs
//
Offset = MI_ZEROING_PTES;
KeFlushProcessTb();
}
//
// Prepare the next PTE
//
PointerPte->u.Hard.PageFrameNumber = Offset - 1;
//
// Write the current PTE
//
TempPte.u.Hard.PageFrameNumber = Page;
PointerPte += Offset;
*PointerPte = TempPte;
//
// Return the address
//
Address = (PVOID)((ULONG_PTR)PointerPte << 10);
return Address;
}
VOID
NTAPI
MiUnmapPageInZeroSpace(IN PVOID Address)
{
//
// Blow away the mapping
//
MiAddressToPte(Address)->u.Long = 0;
}