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exectos/xtoskrnl/mm/mmgr.cc
Aiken Harris 7f0ca6a948
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Compute PTE count per page from entry size
2025-12-15 13:56:39 +01:00

140 lines
4.2 KiB
C++

/**
* PROJECT: ExectOS
* COPYRIGHT: See COPYING.md in the top level directory
* FILE: xtoskrnl/mm/mmgr.cc
* DESCRIPTION: Memory Manager
* DEVELOPERS: Rafal Kupiec <belliash@codingworkshop.eu.org>
* Aiken Harris <harraiken91@gmail.com>
*/
#include <xtos.hh>
/**
* Retrieves a pointer to the system's virtual memory layout structure.
*
* @return This routine returns a pointer to the memory layout structure.
*
* @since XT 1.0
*/
XTAPI
PMMMEMORY_LAYOUT
MM::Manager::GetMemoryLayout(VOID)
{
/* Return a pointer to the global memory layout structure */
return &MemoryLayout;
}
/**
* Initializes the kernel's virtual memory layout.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
MM::Manager::InitializeMemoryLayout(VOID)
{
ULONG_PTR PagedPoolSize, PteCount;
PFN_NUMBER PfnDatabaseSize;
ULONG PtesPerPage;
/* Get the number of PTEs per page and calculate size of paged pool (at least 32MiB) */
PtesPerPage = MM::Pte::GetPtesPerPage();
PteCount = ((SIZE_TO_PAGES(33554432) + (PtesPerPage - 1)) / PtesPerPage);
PagedPoolSize = PteCount * PtesPerPage * MM_PAGE_SIZE;
/* Retrieve the PFN database size */
PfnDatabaseSize = MM::Pfn::GetPfnDatabaseSize();
if(MM::Paging::GetXpaStatus())
{
MemoryLayout.PfnDatabaseAddress = (PMMPFN)0xFFFEFA8000000000ULL;
MemoryLayout.SelfMapAddress = (PVOID)0xFFEDF6FB7DBEDF68ULL;
MemoryLayout.NonPagedPoolStart = (PVOID)((ULONG_PTR)MemoryLayout.PfnDatabaseAddress + PfnDatabaseSize * MM_PAGE_SIZE);
MemoryLayout.NonPagedPoolEnd = (PVOID)0xFFFEFFFFFFBFFFFFULL;
MemoryLayout.PagedPoolStart = (PVOID)0xFFFEF8A000000000ULL;
MemoryLayout.PagedPoolEnd = (PVOID)(((ULONG_PTR)MemoryLayout.PagedPoolStart + PagedPoolSize) - 1);
}
else
{
MemoryLayout.PfnDatabaseAddress = (PMMPFN)0xFFFFFA8000000000ULL;
MemoryLayout.SelfMapAddress = (PVOID)0xFFFFF6FB7DBEDF68ULL;
MemoryLayout.NonPagedPoolStart = (PVOID)((ULONG_PTR)MemoryLayout.PfnDatabaseAddress + PfnDatabaseSize * MM_PAGE_SIZE);
MemoryLayout.NonPagedPoolEnd = (PVOID)0xFFFFFFFFFFBFFFFFULL;
MemoryLayout.PagedPoolStart = (PVOID)0xFFFFF8A000000000ULL;
MemoryLayout.PagedPoolEnd = (PVOID)(((ULONG_PTR)MemoryLayout.PagedPoolStart + PagedPoolSize) - 1);
}
}
/**
* Performs an early initialization of the XTOS Memory Manager.
*
* @return This routine does not return any value.
*
* @since XT 1.0
*/
XTAPI
VOID
MM::Manager::InitializeMemoryManager(VOID)
{
/* Scan memory descriptors provided by the boot loader */
MM::Pfn::ScanMemoryDescriptors();
/* Check if there are enough physical pages */
if(MM::Pfn::GetNumberOfPhysicalPages() < MM_MINIMUM_PHYSICAL_PAGES)
{
/* Insufficient physical pages, kernel panic */
DebugPrint(L"Insufficient physical pages! Install additional memory\n");
KE::Crash::Panic(0);
}
/* Compute allocation size for the PFN database */
MM::Pfn::ComputePfnDatabaseSize();
/* Initialize memory layout */
InitializeMemoryLayout();
}
/**
* Checks whether the specified memory type should be considered as free.
*
* @param MemoryType
* Specifies the memory type to verify.
*
* @return This routine returns TRUE if the specified memory type should be considered as free, or FALSE otherwise.
*
* @since XT 1.0
*/
XTAPI
BOOLEAN
MM::Manager::VerifyMemoryTypeFree(LOADER_MEMORY_TYPE MemoryType)
{
return ((MemoryType == LoaderFirmwareTemporary) ||
(MemoryType == LoaderFree) ||
(MemoryType == LoaderLoadedProgram) ||
(MemoryType == LoaderOsloaderStack));
}
/**
* Checks whether the specified memory type should be considered as invisible for the memory manager.
*
* @param MemoryType
* Specifies the memory type to verify.
*
* @return This routine returns TRUE if the specified memory type should be considered as invisible, or FALSE otherwise.
*
* @since XT 1.0
*/
XTAPI
BOOLEAN
MM::Manager::VerifyMemoryTypeInvisible(LOADER_MEMORY_TYPE MemoryType)
{
return ((MemoryType == LoaderBBTMemory) ||
(MemoryType == LoaderFirmwarePermanent) ||
(MemoryType == LoaderSpecialMemory));
}