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Initialize page directory for non-PAE paging
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Aiken Harris 2025-08-04 14:05:58 +02:00 committed by CodingWorkshop Signing Team
parent ca6c913fa7
commit 0d3fb550f2
Signed by: CodingWorkshop Signing Team
GPG Key ID: 6DC88369C82795D2
1 changed files with 44 additions and 29 deletions
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73
xtldr/arch/i686/memory.c
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@ -31,39 +31,54 @@ BlBuildPageMap(IN PXTBL_PAGE_MAPPING PageMap,
EFI_STATUS Status;
ULONG Index;
/* Allocate pages for the Page Map */
Status = BlAllocateMemoryPages(1, &Address);
if(Status != STATUS_EFI_SUCCESS)
/* Check the page map level to determine which paging structure to create. */
if(PageMap->PageMapLevel == 3)
{
/* Memory allocation failure */
return Status;
/* Allocate a page for the 3-level page map structure (PAE enabled) */
Status = BlAllocateMemoryPages(1, &Address);
if(Status != STATUS_EFI_SUCCESS)
{
/* Memory allocation failed, cannot proceed with page map creation */
return Status;
}
/* Assign the allocated page to the page map and zero it out */
PageMap->PtePointer = (PVOID)(UINT_PTR)Address;
RtlZeroMemory(PageMap->PtePointer, EFI_PAGE_SIZE);
/* Allocate 4 pages for the Page Directories (PDs) */
Status = BlAllocateMemoryPages(4, &DirectoryAddress);
if(Status != STATUS_EFI_SUCCESS)
{
/* Memory allocation failed, cannot proceed with page map creation */
return Status;
}
/* Zero-fill the allocated memory for the Page Directories */
RtlZeroMemory((PVOID)DirectoryAddress, EFI_PAGE_SIZE * 4);
/* Fill the PDPT with pointers to the Page Directories */
for(Index = 0; Index < 4; Index++)
{
RtlZeroMemory(&((PHARDWARE_PTE)PageMap->PtePointer)[Index], sizeof(HARDWARE_PTE));
((PHARDWARE_PTE)PageMap->PtePointer)[Index].PageFrameNumber = DirectoryAddress / EFI_PAGE_SIZE;
((PHARDWARE_PTE)PageMap->PtePointer)[Index].Valid = 1;
DirectoryAddress += EFI_PAGE_SIZE;
}
}
/* Assign and zero-fill memory used by page mappings */
PageMap->PtePointer = (PVOID)(UINT_PTR)Address;
RtlZeroMemory(PageMap->PtePointer, EFI_PAGE_SIZE);
/* Allocate pages for the Page Directory */
Status = BlAllocateMemoryPages(4, &DirectoryAddress);
if(Status != STATUS_EFI_SUCCESS)
else
{
/* Memory allocation failure */
return Status;
}
/* Allocate a page for the 2-level page map structure (PAE disabled) */
Status = BlAllocateMemoryPages(1, &Address);
if(Status != STATUS_EFI_SUCCESS)
{
/* Memory allocation failed, cannot proceed with page map creation */
return Status;
}
/* Zero fill memory used by Page Directory */
RtlZeroMemory((PVOID)DirectoryAddress, EFI_PAGE_SIZE * 4);
/* Set the page directory into the PDPT and mark it present */
for(Index = 0; Index < 4; Index++)
{
/* Set paging entry settings */
RtlZeroMemory(&((PHARDWARE_PTE)PageMap->PtePointer)[Index], sizeof(HARDWARE_PTE));
((PHARDWARE_PTE)PageMap->PtePointer)[Index].PageFrameNumber = DirectoryAddress / EFI_PAGE_SIZE;
((PHARDWARE_PTE)PageMap->PtePointer)[Index].Valid = 1;
/* Next valid PFN address */
DirectoryAddress += EFI_PAGE_SIZE;
/* Assign the allocated page to the page map and zero it out */
PageMap->PtePointer = (PVOID)(UINT_PTR)Address;
RtlZeroMemory(PageMap->PtePointer, EFI_PAGE_SIZE);
}
/* Add page mapping itself to memory mapping */