VOID
FASTCALL
KiEnterV86Mode(IN ULONG_PTR StackFrameUnaligned)
{
PKTHREAD Thread;
PKV8086_STACK_FRAME StackFrame = (PKV8086_STACK_FRAME)(ROUND_UP(StackFrameUnaligned - 4, 16) + 4);
PKTRAP_FRAME TrapFrame = &StackFrame->TrapFrame;
PKV86_FRAME V86Frame = &StackFrame->V86Frame;
PFX_SAVE_AREA NpxFrame = &StackFrame->NpxArea;
ASSERT((ULONG_PTR)NpxFrame % 16 == 0);
/* Build fake user-mode trap frame */
TrapFrame->SegCs = KGDT_R0_CODE | RPL_MASK;
TrapFrame->SegEs = TrapFrame->SegDs = TrapFrame->SegFs = TrapFrame->SegGs = 0;
TrapFrame->ErrCode = 0;
/* Get the current thread's initial stack */
Thread = KeGetCurrentThread();
V86Frame->ThreadStack = KiGetThreadNpxArea(Thread);
/* Save TEB addresses */
V86Frame->ThreadTeb = Thread->Teb;
V86Frame->PcrTeb = KeGetPcr()->NtTib.Self;
/* Save return EIP */
TrapFrame->Eip = (ULONG_PTR)Ki386BiosCallReturnAddress;
/* Save our stack (after the frames) */
TrapFrame->Esi = StackFrameUnaligned;
TrapFrame->Edi = (ULONG_PTR)_AddressOfReturnAddress() + 4;
/* Sanitize EFlags and enable interrupts */
TrapFrame->EFlags = __readeflags() & 0x60DD7;
TrapFrame->EFlags |= EFLAGS_INTERRUPT_MASK;
/* Fill out the rest of the frame */
TrapFrame->HardwareSegSs = KGDT_R3_DATA | RPL_MASK;
TrapFrame->HardwareEsp = 0x11FFE;
TrapFrame->ExceptionList = EXCEPTION_CHAIN_END;
TrapFrame->Dr7 = 0;
/* Set some debug fields if trap debugging is enabled */
KiFillTrapFrameDebug(TrapFrame);
/* Disable interrupts */
_disable();
/* Copy the thread's NPX frame */
RtlCopyMemory(NpxFrame, V86Frame->ThreadStack, sizeof(FX_SAVE_AREA));
/* Clear exception list */
KeGetPcr()->NtTib.ExceptionList = EXCEPTION_CHAIN_END;
/* Set new ESP0 */
KeGetPcr()->TSS->Esp0 = (ULONG_PTR)&TrapFrame->V86Es;
/* Set new initial stack */
Thread->InitialStack = V86Frame;
/* Set VDM TEB */
Thread->Teb = (PTEB)TRAMPOLINE_TEB;
KiSetTebBase(KeGetPcr(), (PVOID)TRAMPOLINE_TEB);
/* Enable interrupts */
_enable();
/* Start VDM execution */
NtVdmControl(VdmStartExecution, NULL);
/* Exit to V86 mode */
KiEoiHelper(TrapFrame);
}
NTSTATUS WINAPI SafeNtVdmControl(ULONG ControlCode,PVOID ControlData)
{
NTSTATUS rc;
if (CheckOldFunction(&OldNtVdmControl))
rc=OldNtVdmControl(ControlCode,ControlData);
else
rc=NtVdmControl(ControlCode,ControlData);
return rc;
}
NTSTATUS
NTAPI
IntInitializeVideoAddressSpace(VOID)
{
OBJECT_ATTRIBUTES ObjectAttributes;
UNICODE_STRING PhysMemName = RTL_CONSTANT_STRING(L"\\Device\\PhysicalMemory");
NTSTATUS Status;
HANDLE PhysMemHandle;
PVOID BaseAddress;
LARGE_INTEGER Offset;
SIZE_T ViewSize;
CHAR IVTAndBda[1024+256];
/* Free the 1MB pre-reserved region. In reality, ReactOS should simply support us mapping the view into the reserved area, but it doesn't. */
BaseAddress = 0;
ViewSize = 1024 * 1024;
Status = ZwFreeVirtualMemory(NtCurrentProcess(),
&BaseAddress,
&ViewSize,
MEM_RELEASE);
if (!NT_SUCCESS(Status))
{
DPRINT1("Couldn't unmap reserved memory (%x)\n", Status);
return 0;
}
/* Open the physical memory section */
InitializeObjectAttributes(&ObjectAttributes,
&PhysMemName,
OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
NULL,
NULL);
Status = ZwOpenSection(&PhysMemHandle,
SECTION_ALL_ACCESS,
&ObjectAttributes);
if (!NT_SUCCESS(Status))
{
DPRINT1("Couldn't open \\Device\\PhysicalMemory\n");
return Status;
}
/* Map the BIOS and device registers into the address space */
Offset.QuadPart = 0xa0000;
ViewSize = 0x100000 - 0xa0000;
BaseAddress = (PVOID)0xa0000;
Status = ZwMapViewOfSection(PhysMemHandle,
NtCurrentProcess(),
&BaseAddress,
0,
ViewSize,
&Offset,
&ViewSize,
ViewUnmap,
0,
PAGE_EXECUTE_READWRITE);
if (!NT_SUCCESS(Status))
{
DPRINT1("Couldn't map physical memory (%x)\n", Status);
ZwClose(PhysMemHandle);
return Status;
}
/* Close physical memory section handle */
ZwClose(PhysMemHandle);
if (BaseAddress != (PVOID)0xa0000)
{
DPRINT1("Couldn't map physical memory at the right address (was %x)\n",
BaseAddress);
return STATUS_UNSUCCESSFUL;
}
/* Allocate some low memory to use for the non-BIOS
* parts of the v86 mode address space
*/
BaseAddress = (PVOID)0x1;
ViewSize = 0xa0000 - 0x1000;
Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
&BaseAddress,
0,
&ViewSize,
MEM_RESERVE | MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
if (!NT_SUCCESS(Status))
{
DPRINT1("Failed to allocate virtual memory (Status %x)\n", Status);
return Status;
}
if (BaseAddress != (PVOID)0x0)
{
DPRINT1("Failed to allocate virtual memory at right address (was %x)\n",
BaseAddress);
return 0;
}
/* Get the real mode IVT and BDA from the kernel */
Status = NtVdmControl(VdmInitialize, IVTAndBda);
if (!NT_SUCCESS(Status))
{
DPRINT1("NtVdmControl failed (status %x)\n", Status);
return Status;
}
/* Return success */
return STATUS_SUCCESS;
}
