88 lines
2.6 KiB
C
88 lines
2.6 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/i686/memory.c
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* DESCRIPTION: EFI memory management for i686 target
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* DEVELOPERS: Rafal Kupiec <belliash@codingworkshop.eu.org>
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*/
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#include <xtos.h>
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/**
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* Builds the actual memory mapping page table and enables paging. This routine exits EFI boot services as well.
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*
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* @param MemoryMappings
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* Supplies a pointer to linked list containing all memory mappings.
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*
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* @param VirtualAddress
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* Supplies a pointer to the next valid, free and available virtual address.
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*
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* @param ImageProtocol
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* A pointer to the EFI loaded image protocol with information about where in memory the loader code was placed.
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*
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* @param PtePointer
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* Supplies a pointer to memory area containing a Page Table Entries (PTE).
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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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XtEnablePaging(IN PXTBL_PAGE_MAPPING PageMap)
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{
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PCPUID_REGISTERS CpuRegisters = NULL;
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EFI_STATUS Status;
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/* Prepare CPUID registers */
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CpuRegisters->Leaf = CPUID_GET_CPU_FEATURES;
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CpuRegisters->SubLeaf = 0;
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CpuRegisters->Eax = 0;
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CpuRegisters->Ebx = 0;
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CpuRegisters->Ecx = 0;
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CpuRegisters->Edx = 0;
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/* Get CPUID */
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ArCpuId(CpuRegisters);
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/* Store PAE status from the CPUID results */
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if(!(CpuRegisters->Edx & CPUID_FEATURES_EDX_PAE))
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{
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/* No PAE support */
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XtLdrProtocol->Debug.Print(L"ERROR: PAE extension not supported by the CPU\n");
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return STATUS_EFI_UNSUPPORTED;
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}
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/* Build page map */
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Status = XtLdrProtocol->Memory.BuildPageMap(PageMap);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Failed to build page map */
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XtLdrProtocol->Debug.Print(L"Failed to build page map (Status code: %zX)\n", Status);
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return Status;
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}
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/* Exit EFI Boot Services */
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XtLdrProtocol->Debug.Print(L"Exiting EFI boot services\n");
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Status = XtLdrProtocol->Util.ExitBootServices();
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Failed to exit boot services */
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XtLdrProtocol->Debug.Print(L"Failed to exit boot services (Status code: %zX)\n", Status);
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return STATUS_EFI_ABORTED;
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}
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/* Enable Physical Address Extension (PAE) */
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ArWriteControlRegister(4, ArReadControlRegister(4) | CR4_PAE);
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/* Write page mappings to CR3 */
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ArWriteControlRegister(3, (UINT_PTR)PageMap->PtePointer);
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/* Enable paging */
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ArWriteControlRegister(0, ArReadControlRegister(0) | CR0_PG);
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/* Return success */
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return STATUS_EFI_SUCCESS;
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}
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