151 lines
4.6 KiB
C++
151 lines
4.6 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: xtoskrnl/mm/init.cc
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* DESCRIPTION: Memory Manager initialization routines
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* DEVELOPERS: Rafal Kupiec <belliash@codingworkshop.eu.org>
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*/
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#include <xtos.hh>
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/**
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* Performs an early initialization of the XTOS Memory Manager.
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*
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* @return This routine does not return any value.
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*
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* @since XT 1.0
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*/
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XTAPI
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VOID
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MM::Init::InitializeMemoryManager(VOID)
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{
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/* Scan memory descriptors provided by the boot loader */
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ScanMemoryDescriptors();
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/* Check if there are enough physical pages */
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if(NumberOfPhysicalPages < MM_MINIMUM_PHYSICAL_PAGES)
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{
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/* Insufficient physical pages, kernel panic */
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DebugPrint(L"Insufficient physical pages! Install additional memory\n");
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KE::Crash::Panic(0);
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}
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/* Proceed with architecture specific initialization */
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InitializeArchitecture();
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}
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/**
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* Scans memory descriptors provided by the boot loader.
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*
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* @return This routine does not return any value.
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*
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* @since XT 1.0
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*/
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XTAPI
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VOID
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MM::Init::ScanMemoryDescriptors(VOID)
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{
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PLIST_ENTRY LoaderMemoryDescriptors, MemoryMappings;
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PLOADER_MEMORY_DESCRIPTOR MemoryDescriptor;
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PFN_NUMBER FreePages;
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/* Initially, set number of free pages to 0 */
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FreePages = 0;
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/* Get a list of memory descriptors provided by the boot loader */
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LoaderMemoryDescriptors = KE::BootInformation::GetMemoryDescriptors();
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/* Iterate through memory mappings provided by the boot loader */
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MemoryMappings = LoaderMemoryDescriptors->Flink;
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while(MemoryMappings != LoaderMemoryDescriptors)
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{
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/* Get memory descriptor */
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MemoryDescriptor = CONTAIN_RECORD(MemoryMappings, LOADER_MEMORY_DESCRIPTOR, ListEntry);
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/* Check if memory type is invisible or cached */
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if(VerifyMemoryTypeInvisible(MemoryDescriptor->MemoryType) ||
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(MemoryDescriptor->MemoryType == LoaderHardwareCachedMemory))
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{
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/* Skip this mapping */
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MemoryMappings = MemoryMappings->Flink;
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continue;
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}
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/* Make sure that memory type is not bad */
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if(MemoryDescriptor->MemoryType != LoaderBad)
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{
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/* Increment number of physical pages */
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NumberOfPhysicalPages += MemoryDescriptor->PageCount;
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}
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/* Find lowest physical page */
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if(MemoryDescriptor->BasePage < LowestPhysicalPage)
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{
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/* Update lowest physical page */
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LowestPhysicalPage = MemoryDescriptor->BasePage;
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}
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/* Find highest physical page */
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if(MemoryDescriptor->BasePage + MemoryDescriptor->PageCount > HighestPhysicalPage)
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{
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/* Update highest physical page */
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HighestPhysicalPage = (MemoryDescriptor->BasePage + MemoryDescriptor->PageCount) - 1;
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}
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/* Check if memory type should be considered as free */
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if(VerifyMemoryTypeFree(MemoryDescriptor->MemoryType))
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{
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/* Check if this descriptor contains more free pages */
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if(MemoryDescriptor->PageCount >= FreePages)
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{
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/* Update free descriptor */
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FreePages = MemoryDescriptor->PageCount;
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FreeDescriptor = MemoryDescriptor;
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}
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}
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/* Get next memory descriptor */
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MemoryMappings = MemoryMappings->Flink;
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}
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/* Store original free descriptor */
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RTL::Memory::CopyMemory(&OldFreeDescriptor, FreeDescriptor, sizeof(LOADER_MEMORY_DESCRIPTOR));
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}
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/** Checks whether the specified memory type should be considered as free.
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*
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* @param MemoryType
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* Specifies the memory type to verify.
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*
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* @return This routine returns TRUE if the specified memory type should be considered as free, or FALSE otherwise.
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*
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* @since XT 1.0
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*/
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XTAPI
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BOOLEAN
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MM::Init::VerifyMemoryTypeFree(LOADER_MEMORY_TYPE MemoryType)
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{
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return ((MemoryType == LoaderFree) || (MemoryType == LoaderFirmwareTemporary) ||
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(MemoryType == LoaderLoadedProgram) || (MemoryType == LoaderOsloaderStack));
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}
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/**
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* Checks whether the specified memory type should be considered as invisible for the memory manager.
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*
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* @param MemoryType
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* Specifies the memory type to verify.
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*
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* @return This routine returns TRUE if the specified memory type should be considered as invisible, or FALSE otherwise.
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*
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* @since XT 1.0
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*/
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XTAPI
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BOOLEAN
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MM::Init::VerifyMemoryTypeInvisible(LOADER_MEMORY_TYPE MemoryType)
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{
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return ((MemoryType == LoaderFirmwarePermanent) ||
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(MemoryType == LoaderSpecialMemory) ||
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(MemoryType == LoaderBBTMemory));
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}
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