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Ensure paging hierarchy exists before processing memory descriptors
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This commit is contained in:
Aiken Harris
2026-02-06 08:40:24 +01:00
parent b51f21f55c
commit 0763a9522b
1 changed files with 19 additions and 8 deletions
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27
xtoskrnl/mm/amd64/pfn.cc
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@@ -282,6 +282,7 @@ MM::Pfn::ProcessMemoryDescriptor(IN PFN_NUMBER BasePage,
IN PFN_NUMBER PageCount,
IN LOADER_MEMORY_TYPE MemoryType)
{
PVOID VirtualRangeStart, VirtualRangeEnd;
PFN_NUMBER PageNumber;
PMMPDE PointerPde;
PMMPFN Pfn;
@@ -303,6 +304,10 @@ MM::Pfn::ProcessMemoryDescriptor(IN PFN_NUMBER BasePage,
}
else
{
/* Calculate the virtual address range for this physical memory region */
VirtualRangeStart = (PVOID)(KSEG0_BASE + (BasePage << MM_PAGE_SHIFT));
VirtualRangeEnd = (PVOID)(KSEG0_BASE + ((BasePage + PageCount) << MM_PAGE_SHIFT));
/* Handle all other (non-free) memory types */
switch(MemoryType)
{
@@ -315,6 +320,12 @@ MM::Pfn::ProcessMemoryDescriptor(IN PFN_NUMBER BasePage,
}
break;
case LoaderXIPRom:
/* Get the page directory entry for the current page */
PointerPde = MM::Paging::GetPdeAddress(VirtualRangeStart);
/* Initialize the page directory entries covering this memory range */
InitializePageDirectory(PointerPde, MM::Paging::GetPdeAddress(VirtualRangeEnd));
/* This memory range contains Read-Only Memory (ROM) */
for(PageNumber = 0; PageNumber < PageCount; PageNumber++)
{
@@ -324,11 +335,8 @@ MM::Pfn::ProcessMemoryDescriptor(IN PFN_NUMBER BasePage,
/* Ensure that the page is not already in-use */
if(Pfn->u3.e2.ReferenceCount == 0)
{
/* Get the page directory entry for the current page */
PointerPde = MM::Paging::GetPdeAddress((PVOID)(KSEG0_BASE + (BasePage << MM_PAGE_SHIFT)));
/* Initialize the PFN entry to represent a ROM page */
Pfn->PteAddress = MM::Paging::GetPteAddress((PVOID)(KSEG0_BASE + (BasePage << MM_PAGE_SHIFT)));
Pfn->PteAddress = MM::Paging::GetPteAddress(VirtualRangeStart);
Pfn->u1.Flink = 0;
Pfn->u2.ShareCount = 0;
Pfn->u3.e1.CacheAttribute = PfnCached;
@@ -342,6 +350,12 @@ MM::Pfn::ProcessMemoryDescriptor(IN PFN_NUMBER BasePage,
}
break;
default:
/* Get the page directory entry for the current page */
PointerPde = MM::Paging::GetPdeAddress(VirtualRangeStart);
/* Initialize the page directory entries covering this memory range */
InitializePageDirectory(PointerPde, MM::Paging::GetPdeAddress(VirtualRangeEnd));
/* All other types are considered in-use (ie, by the kernel, ACPI, etc) */
for(PageNumber = 0; PageNumber < PageCount; PageNumber++)
{
@@ -351,11 +365,8 @@ MM::Pfn::ProcessMemoryDescriptor(IN PFN_NUMBER BasePage,
/* Ensure that the page is not already in-use */
if(Pfn->u3.e2.ReferenceCount == 0)
{
/* Get the page directory entry for the current page */
PointerPde = MM::Paging::GetPdeAddress((PVOID)(KSEG0_BASE + (BasePage << MM_PAGE_SHIFT)));
/* Initialize the PFN entry to represent an in-use page and prevent it from being allocated */
Pfn->PteAddress = MM::Paging::GetPteAddress((PVOID)(KSEG0_BASE + (BasePage << MM_PAGE_SHIFT)));
Pfn->PteAddress = MM::Paging::GetPteAddress(VirtualRangeStart);
Pfn->u2.ShareCount++;
Pfn->u3.e1.CacheAttribute = PfnCached;
Pfn->u3.e1.PageLocation = ActiveAndValid;