111 lines
3.0 KiB
C++
111 lines
3.0 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/i686/paging.cc
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* DESCRIPTION: Architecture dependent paging support
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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.hh>
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/**
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* Checks if eXtended Physical Addressing (XPA) is enabled.
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*
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* @return This routine returns TRUE if PAE is enabled, 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::Paging::GetExtendedPhysicalAddressingStatus(VOID)
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{
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/* Check if PAE is enabled */
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return ((AR::CpuFunc::ReadControlRegister(4) & CR4_PAE) != 0) ? TRUE : FALSE;
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}
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/**
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* Maps a specific virtual address to a specific physical page frame (i686 specific).
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*
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* @param VirtualAddress
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* The virtual address to map.
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*
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* @param PageFrameNumber
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* The physical frame number to back the virtual address.
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*
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* @param Attributes
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* Specifies the attributes (protections, caching) to apply to the 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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XTAPI
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XTSTATUS
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MM::Paging::MapVirtualAddress(IN PVOID VirtualAddress,
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IN PFN_NUMBER PageFrameNumber,
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IN ULONGLONG Attributes)
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{
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MMPTE TemplatePte;
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PMMPTE PointerPte;
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/* Initialize the template PTE */
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MM::Paging::ClearPte(&TemplatePte);
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MM::Paging::SetPte(&TemplatePte, 0, Attributes | MM_PTE_CACHE_ENABLE);
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/* Check if XPA is enabled */
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if(MM::Paging::GetXpaStatus())
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{
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/* Map Page Directory Pointer Table */
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MM::Pte::MapPPE(VirtualAddress, VirtualAddress, (PMMPPE)&TemplatePte);
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}
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/* Map Page Directory Entry */
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MM::Pte::MapPDE(VirtualAddress, VirtualAddress, (PMMPDE)&TemplatePte);
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/* Get PTE address */
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PointerPte = MM::Paging::GetPteAddress(VirtualAddress);
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/* Initialize the template PTE */
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MM::Paging::ClearPte(&TemplatePte);
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MM::Paging::SetPte(&TemplatePte, PageFrameNumber, Attributes);
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/* Write the PTE */
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MM::Paging::WritePte(PointerPte, TemplatePte);
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/* Flush the TLB to reflect the changes */
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MM::Paging::FlushTlb();
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/* Return success */
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return STATUS_SUCCESS;
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}
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/**
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* Fills a section of memory with zeroes like RtlZeroMemory(), but in more efficient way.
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*
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* @param Address
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* Supplies an address of the page to be filled with zeroes.
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*
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* @param Size
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* Number of bytes to be filled with zeros. This always should be a multiply of page size.
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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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XTFASTCALL
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VOID
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MM::Paging::ZeroPages(IN PVOID Address,
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IN ULONG Size)
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{
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__asm__ volatile("xor %%eax, %%eax\n"
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"rep stosb"
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: "=D"(Address),
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"=c"(Size)
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: "0"(Address),
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"1"(Size),
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"a"(0)
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: "memory");
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}
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