86 lines
2.0 KiB
C
86 lines
2.0 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/pmap.c
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* DESCRIPTION: Low-level support for i686 page map manipulation
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* DEVELOPERS: Aiken Harris <harraiken91@gmail.com>
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*/
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#include <xtos.h>
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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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MmpGetExtendedPhysicalAddressingStatus(VOID)
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{
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/* Check if PAE is enabled */
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return ((ArReadControlRegister(4) & CR4_PAE) != 0) ? TRUE : FALSE;
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}
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/**
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* Gets the address of the PDE (Page Directory Entry), that maps given address.
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*
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* @param Address
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* Specifies the virtual address for which to retrieve the corresponding PDE.
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*
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* @return This routine returns the address of the PDE.
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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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PMMPDE
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MmpGetPdeAddress(PVOID Address)
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{
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ULONG Offset;
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/* Calculate offset and return PTE address */
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Offset = ((((ULONG)(Address)) >> MmpPageMapInfo.PdiShift) << MmpPageMapInfo.PteShift);
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return (PMMPTE)(MmpPageMapInfo.PdeBase + Offset);
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}
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/**
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* Gets the address of the PPE (Page Directory Pointer Table Entry), that maps given address.
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*
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* @param Address
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* Specifies the virtual address for which to retrieve the corresponding PDE.
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*
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* @return This routine returns the address of the PPE.
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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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PMMPPE
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MmpGetPpeAddress(PVOID Address)
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{
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/* Return zero */
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return 0;
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}
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/**
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* Gets the address of the PTE (Page Table Entry), that maps given address.
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*
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* @param Address
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* Specifies the virtual address for which to retrieve the corresponding PTE.
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*
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* @return This routine returns the address of the PTE.
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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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PMMPTE
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MmpGetPteAddress(PVOID Address)
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{
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ULONG Offset;
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/* Calculate offset and return PTE address */
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Offset = ((((ULONG)(Address)) >> MM_PTI_SHIFT) << MmpPageMapInfo.PteShift);
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return (PMMPTE)(MM_PTE_BASE + Offset);
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}
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