137 lines
4.1 KiB
C
137 lines
4.1 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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* Aiken Harris <harraiken91@gmail.com>
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*/
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#include <xtos.h>
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/**
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* Allocates and maps the 4MB hardware layer memory pool.
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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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* @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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XtpMapHardwareMemoryPool(IN PXTBL_PAGE_MAPPING PageMap)
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{
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EFI_PHYSICAL_ADDRESS Address;
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EFI_STATUS Status;
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/* Allocate a contiguous 4MB block of physical memory */
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Status = XtLdrProtocol->Memory.AllocatePages(MM_HARDWARE_POOL_PAGE_COUNT, &Address);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Memory allocation failed, return error */
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return Status;
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}
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/* Map all the memory for the hardware layer */
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Status = XtLdrProtocol->Memory.MapPage(PageMap, MM_HARDWARE_VA_START, Address, MM_HARDWARE_POOL_PAGE_COUNT);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Memory mapping failed, free memory and return error */
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XtLdrProtocol->Memory.FreePages(MM_HARDWARE_POOL_PAGE_COUNT, Address);
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return Status;
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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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/**
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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 PageMap
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* Supplies a pointer to the page mapping structure.
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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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CPUID_REGISTERS CpuRegisters;
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EFI_STATUS Status;
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/* Prepare CPUID registers */
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RtlZeroMemory(&CpuRegisters, sizeof(CPUID_REGISTERS));
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CpuRegisters.Leaf = CPUID_GET_CPU_FEATURES;
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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, 0xC0000000);
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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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/* Map memory for hardware layer */
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Status = XtpMapHardwareMemoryPool(PageMap);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Failed to map memory for hardware layer */
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XtLdrProtocol->Debug.Print(L"Failed to map memory for hardware layer (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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/* Disable paging */
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ArWriteControlRegister(0, ArReadControlRegister(0) & ~CR0_PG);
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/* Check the configured page map level to set the PAE state accordingly */
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if(PageMap->PageMapLevel == 3)
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{
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/* Enable Physical Address Extension (PAE) */
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XtLdrProtocol->Debug.Print(L"Enabling Physical Address Extension (PAE)\n");
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ArWriteControlRegister(4, ArReadControlRegister(4) | CR4_PAE);
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}
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else
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{
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/* Disable Physical Address Extension (PAE) */
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XtLdrProtocol->Debug.Print(L"Disabling Physical Address Extension (PAE)\n");
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ArWriteControlRegister(4, ArReadControlRegister(4) & ~CR4_PAE);
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}
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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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