mirror of
https://github.com/reactos/reactos.git
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124 lines
4.1 KiB
C
124 lines
4.1 KiB
C
/*
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* PROJECT: ReactOS Kernel
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* LICENSE: GPL - See COPYING in the top level directory
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* FILE: ntoskrnl/ke/i386/v86vdm.c
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* PURPOSE: Manages the Kernel's support for Virtual-8086 Mode (V86)
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* used by Video Drivers to access ROM BIOS functions, as well
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* as the kernel architecture part of generic VDM support.
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* PROGRAMMERS: Alex Ionescu (alex.ionescu@reactos.org)
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*/
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/* INCLUDES ******************************************************************/
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#include <ntoskrnl.h>
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#define NDEBUG
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#include <debug.h>
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/* GLOBALS *******************************************************************/
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ULONG KeI386EFlagsAndMaskV86 = EFLAGS_USER_SANITIZE;
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ULONG KeI386EFlagsOrMaskV86 = EFLAGS_INTERRUPT_MASK;
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PVOID Ki386IopmSaveArea;
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BOOLEAN KeI386VirtualIntExtensions = FALSE;
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/* PRIVATE FUNCTIONS *********************************************************/
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/* PUBLIC FUNCTIONS **********************************************************/
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/*
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* @implemented
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*/
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NTSTATUS
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NTAPI
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Ke386CallBios(IN ULONG Int,
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OUT PCONTEXT Context)
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{
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PUCHAR Trampoline = (PUCHAR)TRAMPOLINE_BASE;
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PTEB VdmTeb = (PTEB)TRAMPOLINE_TEB;
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PVDM_TIB VdmTib = (PVDM_TIB)TRAMPOLINE_TIB;
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ULONG ContextSize = FIELD_OFFSET(CONTEXT, ExtendedRegisters);
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PKTHREAD Thread = KeGetCurrentThread();
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PKTSS Tss = KeGetPcr()->TSS;
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PKPROCESS Process = Thread->ApcState.Process;
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PVDM_PROCESS_OBJECTS VdmProcessObjects;
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USHORT OldOffset, OldBase;
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/* Start with a clean TEB */
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RtlZeroMemory(VdmTeb, sizeof(TEB));
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/* Write the interrupt and bop */
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*Trampoline++ = 0xCD;
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*Trampoline++ = (UCHAR)Int;
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*(PULONG)Trampoline = TRAMPOLINE_BOP;
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/* Setup the VDM TEB and TIB */
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VdmTeb->Vdm = (PVOID)TRAMPOLINE_TIB;
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RtlZeroMemory(VdmTib, sizeof(VDM_TIB));
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VdmTib->Size = sizeof(VDM_TIB);
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/* Set a blank VDM state */
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*VdmState = 0;
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/* Copy the context */
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RtlCopyMemory(&VdmTib->VdmContext, Context, ContextSize);
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VdmTib->VdmContext.SegCs = (ULONG_PTR)Trampoline >> 4;
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VdmTib->VdmContext.SegSs = (ULONG_PTR)Trampoline >> 4;
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VdmTib->VdmContext.Eip = 0;
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VdmTib->VdmContext.Esp = 2 * PAGE_SIZE - sizeof(ULONG_PTR);
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VdmTib->VdmContext.EFlags |= EFLAGS_V86_MASK | EFLAGS_INTERRUPT_MASK;
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VdmTib->VdmContext.ContextFlags = CONTEXT_FULL;
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/* This can't be a real VDM process */
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ASSERT(PsGetCurrentProcess()->VdmObjects == NULL);
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/* Allocate VDM structure */
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VdmProcessObjects = ExAllocatePoolWithTag(NonPagedPool,
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sizeof(VDM_PROCESS_OBJECTS),
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TAG('K', 'e', ' ', ' '));
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if (!VdmProcessObjects) return STATUS_NO_MEMORY;
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/* Set it up */
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RtlZeroMemory(VdmProcessObjects, sizeof(VDM_PROCESS_OBJECTS));
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VdmProcessObjects->VdmTib = VdmTib;
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PsGetCurrentProcess()->VdmObjects = VdmProcessObjects;
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/* Set the system affinity for the current thread */
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KeSetSystemAffinityThread(1);
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/* Make sure there's space for two IOPMs, then copy & clear the current */
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ASSERT(((PKIPCR)KeGetPcr())->GDT[KGDT_TSS / 8].LimitLow >=
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(0x2000 + IOPM_OFFSET - 1));
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RtlCopyMemory(Ki386IopmSaveArea, &Tss->IoMaps[0].IoMap, PAGE_SIZE * 2);
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RtlZeroMemory(&Tss->IoMaps[0].IoMap, PAGE_SIZE * 2);
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/* Save the old offset and base, and set the new ones */
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OldOffset = Process->IopmOffset;
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OldBase = Tss->IoMapBase;
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Process->IopmOffset = (USHORT)IOPM_OFFSET;
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Tss->IoMapBase = (USHORT)IOPM_OFFSET;
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/* Switch stacks and work the magic */
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Ki386SetupAndExitToV86Mode(VdmTeb);
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/* Restore IOPM */
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RtlCopyMemory(&Tss->IoMaps[0].IoMap, Ki386IopmSaveArea, PAGE_SIZE * 2);
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Process->IopmOffset = OldOffset;
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Tss->IoMapBase = OldBase;
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/* Restore affinity */
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KeRevertToUserAffinityThread();
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/* Restore context */
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RtlCopyMemory(Context, &VdmTib->VdmContext, ContextSize);
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Context->ContextFlags = CONTEXT_FULL;
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/* Free VDM objects */
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ExFreePool(PsGetCurrentProcess()->VdmObjects);
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PsGetCurrentProcess()->VdmObjects = NULL;
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/* Return status */
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return STATUS_SUCCESS;
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}
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/* EOF */
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