98 lines
2.7 KiB
C
98 lines
2.7 KiB
C
/**
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* PROJECT: ExectOS
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* COPYRIGHT: See COPYING.md in the top level directory
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* FILE: xtldr/arch/i686/memory.c
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* DESCRIPTION: XT Boot Loader i686 specific memory management
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* DEVELOPERS: Rafal Kupiec <belliash@codingworkshop.eu.org>
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*/
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#include <xtldr.h>
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/**
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* Does the actual virtual memory mapping.
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*
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* @param PageMap
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* Supplies a pointer to the page mapping structure.
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*
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* @param VirtualAddress
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* Supplies a virtual address of the mapping.
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*
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* @param PhysicalAddress
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* Supplies a physical address of the mapping.
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*
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* @param NumberOfPages
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* Supplies a number of the pages of the mapping.
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*
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* @return This routine returns a status code.
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*
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* @since XT 1.0
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*/
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XTCDECL
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EFI_STATUS
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BlMapPage(IN PXTBL_PAGE_MAPPING PageMap,
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IN UINT_PTR VirtualAddress,
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IN UINT_PTR PhysicalAddress,
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IN UINT NumberOfPages)
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{
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SIZE_T Pml1Entry, Pml2Entry, Pml3Entry;
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PHARDWARE_PTE Pml1, Pml2, Pml3;
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SIZE_T PageFrameNumber;
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EFI_STATUS Status;
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/* Set the Page Frame Number (PFN) */
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PageFrameNumber = PhysicalAddress >> EFI_PAGE_SHIFT;
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/* Do the recursive mapping */
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while(NumberOfPages > 0)
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{
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/* Calculate the indices in the various Page Tables from the virtual address */
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Pml3Entry = (VirtualAddress & ((ULONGLONG)0x1FF << 30)) >> 30;
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Pml2Entry = (VirtualAddress & ((ULONGLONG)0x1FF << 21)) >> 21;
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Pml1Entry = (VirtualAddress & ((ULONGLONG)0x1FF << 12)) >> 12;
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/* Check page map level */
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if(PageMap->PageMapLevel == 3)
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{
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/* Three level Page Map */
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Pml3 = ((PHARDWARE_PTE)(PageMap->PtePointer));
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/* Get PML2 */
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Status = BlpGetNextPageTable(PageMap, Pml3, Pml3Entry, &Pml2);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Memory mapping failure */
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return Status;
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}
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}
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else
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{
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/* Two level Page Map */
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Pml2 = ((PHARDWARE_PTE)(PageMap->PtePointer));
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}
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/* Get PML1 */
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Status = BlpGetNextPageTable(PageMap, Pml2, Pml2Entry, &Pml1);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Memory mapping failure */
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return Status;
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}
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/* Set paging entry settings */
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Pml1[Pml1Entry].PageFrameNumber = PageFrameNumber;
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Pml1[Pml1Entry].Valid = 1;
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Pml1[Pml1Entry].Write = 1;
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/* Take next virtual address and PFN */
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VirtualAddress += EFI_PAGE_SIZE;
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PageFrameNumber++;
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/* Decrease number of pages left */
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NumberOfPages--;
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}
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/* Return success */
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return STATUS_EFI_SUCCESS;
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}
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