forked from xt-sys/exectos
Setup processor context (GDT, PCR, TSS) and kernel startup stack before booting XTOS
This commit is contained in:
278
xtldr/modules/xtos/i686/cpu.c
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278
xtldr/modules/xtos/i686/cpu.c
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/**
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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/modules/xtos/i686/cpu.c
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* DESCRIPTION: XTOS i686 processor context
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* DEVELOPERS: Rafal Kupiec <belliash@codingworkshop.eu.org>
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*/
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#include <xtos.h>
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/**
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* Fills in an AMD64 GDT entry.
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*
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* @param Gdt
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* Supplies a pointer to the GDT.
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*
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* @param Selector
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* Specifies a segment selector of the GDT entry.
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*
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* @param Base
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* Specifies a base address value of the descriptor.
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*
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* @param Limit
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* Specifies a descriptor limit.
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*
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* @param Type
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* Specifies a type of the descriptor.
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*
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* @param Dpl
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* Specifies the descriptor privilege level.
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*
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* @param SegmentMode
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* Specifies a segment mode of the descriptor.
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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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XTCDECL
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VOID
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XtpInitializeGdtEntry(IN PKGDTENTRY Gdt,
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IN USHORT Selector,
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IN ULONGLONG Base,
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IN ULONG Limit,
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IN UCHAR Type,
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IN UCHAR Dpl,
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IN UCHAR SegmentMode)
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{
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PKGDTENTRY GdtEntry;
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UCHAR Granularity;
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/* Set the granularity flag depending on descriptor limit */
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if(Limit < 0x100000)
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{
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/* Limit is in 1B blocks */
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Granularity = 0;
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}
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else
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{
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/* Limit is in 4KB blocks */
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Granularity = 1;
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Limit >>= 12;
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}
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/* Get GDT entry */
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GdtEntry = (PKGDTENTRY)((ULONG64)Gdt + (Selector & ~RPL_MASK));
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/* Set GDT descriptor base */
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GdtEntry->BaseLow = Base & 0xFFFF;
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GdtEntry->Bits.BaseMiddle = (Base >> 16) & 0xFF;
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GdtEntry->Bits.BaseHigh = (Base >> 24) & 0xFF;
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/* Set descriptor limit */
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GdtEntry->LimitLow = Limit & 0xFFFF;
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GdtEntry->Bits.LimitHigh = (Limit >> 16) & 0xF;
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/* Initialize GDT entry */
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GdtEntry->Bits.DefaultBig = (SegmentMode & 2);
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GdtEntry->Bits.Dpl = (Dpl & 0x3);
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GdtEntry->Bits.Granularity = Granularity;
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GdtEntry->Bits.Reserved0 = 0;
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GdtEntry->Bits.Present = (Type != 0);
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GdtEntry->Bits.System = 0;
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GdtEntry->Bits.Type = (Type & 0x1F);
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}
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#define PCR_PAGES 7
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/**
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* Initializes GDT, PCR and TSS descriptors.
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*
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* @param MemoryMappings
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* Supplies a pointer to linked list containing all memory mappings.
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*
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* @param VirtualAddress
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* Supplies a pointer to the next valid, free and available virtual address.
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*
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* @param Gdt
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* Supplies a pointer to memory area containing GDT to fill in.
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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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XtpInitializeDescriptors(IN PLIST_ENTRY MemoryMappings,
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IN PVOID *VirtualAddress,
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OUT PKGDTENTRY *Gdt)
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{
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EFI_PHYSICAL_ADDRESS GdtAddress, PcrAddress, TssAddress;
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PKTSS PhysicalTss, Tss;
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PVOID PhysicalPcr, Pcr;
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PKGDTENTRY GdtEntry;
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EFI_STATUS Status;
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/* Print debug message */
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XtLdrProtocol->DbgPrint(L"Initializing Task State Segment (TSS)\n");
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/* Allocate memory for TSS */
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Status = XtLdrProtocol->AllocatePages(EFI_SIZE_TO_PAGES(sizeof(KTSS)), &TssAddress);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Memory allocation failure */
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XtLdrProtocol->DbgPrint(L"Failed to allocate pages for TSS (Status Code: %lx)\n", Status);
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return Status;
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}
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/* Set TSS and fill it with zeroes */
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PhysicalTss = (PKTSS)(UINT_PTR)TssAddress;
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RtlZeroMemory(PhysicalTss, EFI_SIZE_TO_PAGES(sizeof(KTSS)) * EFI_PAGE_SIZE);
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/* Map TSS and set its virtual address */
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XtLdrProtocol->AddVirtualMemoryMapping(MemoryMappings, *VirtualAddress, PhysicalTss,
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EFI_SIZE_TO_PAGES(sizeof(KTSS)), LoaderMemoryData);
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Tss = (PKTSS)*VirtualAddress;
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/* Set next valid virtual address */
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*VirtualAddress += EFI_SIZE_TO_PAGES(sizeof(KTSS)) * EFI_PAGE_SIZE;
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/* Print debug message */
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XtLdrProtocol->DbgPrint(L"Initializing Processor Control Region (PCR)\n");
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/* Allocate memory for PCR */
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Status = XtLdrProtocol->AllocatePages(PCR_PAGES, &PcrAddress);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* Memory allocation failure */
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XtLdrProtocol->DbgPrint(L"Failed to allocate pages for PCR (Status Code: %lx)\n", Status);
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return Status;
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}
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/* Set PCR and fill it with zeroes */
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PhysicalPcr = (PVOID)(UINT_PTR)PcrAddress;
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RtlZeroMemory(PhysicalPcr, PCR_PAGES * EFI_PAGE_SIZE);
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/* Map TSS and set its virtual address */
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XtLdrProtocol->AddVirtualMemoryMapping(MemoryMappings, *VirtualAddress, PhysicalPcr,
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PCR_PAGES, LoaderStartupPcrPage);
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Pcr = *VirtualAddress;
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/* Set next valid virtual address */
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*VirtualAddress += PCR_PAGES * EFI_PAGE_SIZE;
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/* Print debug message */
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XtLdrProtocol->DbgPrint(L"Initializing General Descriptor Table (GDT)\n");
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/* Allocate memory for GDT */
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Status = XtLdrProtocol->AllocatePages(EFI_SIZE_TO_PAGES(128 * sizeof(KGDTENTRY)), &GdtAddress);
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if (Status != STATUS_EFI_SUCCESS) {
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/* Memory allocation failure */
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XtLdrProtocol->DbgPrint(L"Failed to allocate pages for GDT (Status Code: %lx)\n", Status);
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return Status;
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}
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/* Set GDT entry and fill it with zeroes */
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GdtEntry = (PKGDTENTRY)(UINT_PTR)GdtAddress;
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RtlZeroMemory(GdtEntry, EFI_SIZE_TO_PAGES(128 * sizeof(KGDTENTRY)) * EFI_PAGE_SIZE);
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/* Initialize GDT entries */
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XtpInitializeGdtEntry(GdtEntry, KGDT_NULL, 0x0, 0x0, 0, KGDT_DPL_SYSTEM, 0);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R0_CODE, 0x0, 0xFFFFFFFF, KGDT_TYPE_CODE, KGDT_DPL_SYSTEM, 2);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R0_DATA, 0x0, 0xFFFFFFFF, KGDT_TYPE_DATA, KGDT_DPL_SYSTEM, 2);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R3_CODE, 0x0, 0xFFFFFFFF, KGDT_TYPE_CODE, KGDT_DPL_USER, 2);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R3_DATA, 0x0, 0xFFFFFFFF, KGDT_TYPE_DATA, KGDT_DPL_USER, 2);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R3_TEB, 0x0, 0xFFF, KGDT_TYPE_DATA | KGDT_DESCRIPTOR_ACCESSED, KGDT_DPL_USER, 2);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R0_LDT, 0x0, 0x0, 0, KGDT_DPL_SYSTEM, 0);
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XtpInitializeGdtEntry(GdtEntry, KGDT_VDM_TILE, 0x0400, 0xFFFF, KGDT_TYPE_DATA, KGDT_DPL_USER, 0);
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XtpInitializeGdtEntry(GdtEntry, KGDT_R0_PCR, (ULONG_PTR)Pcr, 0x1, KGDT_TYPE_DATA, KGDT_DPL_SYSTEM, 2);
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XtpInitializeGdtEntry(GdtEntry, KGDT_SYS_TSS, (ULONG_PTR)Tss, sizeof(KTSS) - 1, I686_TSS, KGDT_DPL_SYSTEM, 0);
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XtpInitializeGdtEntry(GdtEntry, KGDT_DF_TSS, 0x20000, 0xFFFF, I686_TSS, KGDT_DPL_SYSTEM, 0);
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XtpInitializeGdtEntry(GdtEntry, KGDT_NMI_TSS, 0x20000, 0xFFFF, KGDT_TYPE_CODE, KGDT_DPL_SYSTEM, 0);
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/* Map GDT and set its virtual address */
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Status = XtLdrProtocol->AddVirtualMemoryMapping(MemoryMappings, *VirtualAddress, GdtEntry,
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EFI_SIZE_TO_PAGES(128 * sizeof(KGDTENTRY)), LoaderMemoryData);
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*Gdt = (PKGDTENTRY)*VirtualAddress;
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/* Set next valid virtual address */
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*VirtualAddress += (EFI_SIZE_TO_PAGES(128 * sizeof(KGDTENTRY)) * EFI_PAGE_SIZE);
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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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* Loads previously prepared CPU context and performs architecture-specific tasks needed to boot XTOS.
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*
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* @param Gdt
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* Supplies a pointer to memory area containing GDT to load.
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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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XTCDECL
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VOID
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XtpLoadProcessorContext(IN PKGDTENTRY Gdt)
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{
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KDESCRIPTOR GdtDescriptor;
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GdtDescriptor.Base = (PVOID)(ULONG_PTR)Gdt;
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GdtDescriptor.Limit = 128 * sizeof(KGDTENTRY) - 1;
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/* Load GDT and TSS */
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HlLoadGlobalDescriptorTable(&GdtDescriptor.Limit);
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HlLoadTaskRegister((UINT32)KGDT_SYS_TSS);
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/* Load PCR in FS segment */
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HlLoadSegment(SEGMENT_FS, KGDT_R0_PCR);
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/* Re-enable IDE interrupts */
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HlIoPortOutByte(0x376, 0);
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HlIoPortOutByte(0x3F6, 0);
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}
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/**
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* Sets architecture specific processor context.
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*
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* @param MemoryMappings
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* Supplies a pointer to linked list containing all memory mappings.
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*
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* @param VirtualAddress
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* Supplies a pointer to the next valid, free and available virtual address.
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*
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* @param Gdt
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* Supplies a pointer to memory area containing GDT to fill in.
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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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XtpSetProcessorContext(IN PLIST_ENTRY MemoryMappings,
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IN PVOID *VirtualAddress,
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OUT PKGDTENTRY *Gdt)
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{
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EFI_STATUS Status;
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/* Print debug message */
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XtLdrProtocol->DbgPrint(L"Setting processor context\n");
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/* Disable interrupts */
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HlClearInterruptFlag();
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/* Initialize GDT */
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Status = XtpInitializeDescriptors(MemoryMappings, VirtualAddress, Gdt);
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if(Status != STATUS_EFI_SUCCESS)
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{
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/* GDT initialization failure */
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XtLdrProtocol->DbgPrint(L"Failed to initialize GDT (Status Code: %lx)\n", Status);
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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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