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#include "BiosVideo.h"
#define EFI_CPU_EFLAGS_IF 0x200
THUNK_CONTEXT mThunkContext;
VOID
InitializeBiosIntCaller (
IN BIOS_VIDEO_DEV *BiosDev
)
{
EFI_STATUS Status;
UINT32 RealModeBufferSize;
UINT32 ExtraStackSize;
EFI_PHYSICAL_ADDRESS LegacyRegionBase;
//
// Get LegacyRegion
//
AsmGetThunk16Properties (&RealModeBufferSize, &ExtraStackSize);
LegacyRegionBase = 0x100000;
Status = gBS->AllocatePages (
AllocateMaxAddress,
EfiACPIMemoryNVS,
EFI_SIZE_TO_PAGES(RealModeBufferSize + ExtraStackSize + 200),
&LegacyRegionBase
);
ASSERT_EFI_ERROR (Status);
mThunkContext.RealModeBuffer = (VOID*)(UINTN)LegacyRegionBase;
mThunkContext.RealModeBufferSize = EFI_PAGES_TO_SIZE (RealModeBufferSize);
mThunkContext.ThunkAttributes = 3;
AsmPrepareThunk16(&mThunkContext);
}
VOID
InitializeInterruptRedirection (
IN BIOS_VIDEO_DEV *BiosDev
)
/*++
Routine Description:
Initialize interrupt redirection code and entries, because
IDT Vectors 0x68-0x6f must be redirected to IDT Vectors 0x08-0x0f.
Or the interrupt will lost when we do thunk.
NOTE: We do not reset 8259 vector base, because it will cause pending
interrupt lost.
Arguments:
NONE
Returns:
NONE
--*/
{
EFI_STATUS Status;
EFI_PHYSICAL_ADDRESS LegacyRegionBase;
UINTN LegacyRegionLength;
UINT32 *IdtArray;
UINTN Index;
UINT8 ProtectedModeBaseVector;
UINT32 InterruptRedirectionCode[] = {
0x90CF08CD, // INT8; IRET; NOP
0x90CF09CD, // INT9; IRET; NOP
0x90CF0ACD, // INTA; IRET; NOP
0x90CF0BCD, // INTB; IRET; NOP
0x90CF0CCD, // INTC; IRET; NOP
0x90CF0DCD, // INTD; IRET; NOP
0x90CF0ECD, // INTE; IRET; NOP
0x90CF0FCD // INTF; IRET; NOP
};
//
// Get LegacyRegion
//
LegacyRegionLength = sizeof(InterruptRedirectionCode);
LegacyRegionBase = 0x100000;
Status = gBS->AllocatePages (
AllocateMaxAddress,
EfiACPIMemoryNVS,
EFI_SIZE_TO_PAGES(LegacyRegionLength),
&LegacyRegionBase
);
ASSERT_EFI_ERROR (Status);
//
// Copy code to legacy region
//
CopyMem ((VOID *)(UINTN)LegacyRegionBase, InterruptRedirectionCode, sizeof (InterruptRedirectionCode));
//
// Get VectorBase, it should be 0x68
//
Status = BiosDev->Legacy8259->GetVector (BiosDev->Legacy8259, Efi8259Irq0, &ProtectedModeBaseVector);
ASSERT_EFI_ERROR (Status);
//
// Patch IVT 0x68 ~ 0x6f
//
IdtArray = (UINT32 *) 0;
for (Index = 0; Index < 8; Index++) {
IdtArray[ProtectedModeBaseVector + Index] = ((EFI_SEGMENT (LegacyRegionBase + Index * 4)) << 16) | (EFI_OFFSET (LegacyRegionBase + Index * 4));
}
return ;
}
BOOLEAN
EFIAPI
LegacyBiosInt86 (
IN BIOS_VIDEO_DEV *BiosDev,
IN UINT8 BiosInt,
IN EFI_IA32_REGISTER_SET *Regs
)
/*++
Routine Description:
Thunk to 16-bit real mode and execute a software interrupt with a vector
of BiosInt. Regs will contain the 16-bit register context on entry and
exit.
Arguments:
This - Protocol instance pointer.
BiosInt - Processor interrupt vector to invoke
Reg - Register contexted passed into (and returned) from thunk to
16-bit mode
Returns:
FALSE - Thunk completed, and there were no BIOS errors in the target code.
See Regs for status.
TRUE - There was a BIOS erro in the target code.
--*/
{
UINTN Status;
UINTN Eflags;
IA32_REGISTER_SET ThunkRegSet;
BOOLEAN Ret;
UINT16 *Stack16;
Regs->X.Flags.Reserved1 = 1;
Regs->X.Flags.Reserved2 = 0;
Regs->X.Flags.Reserved3 = 0;
Regs->X.Flags.Reserved4 = 0;
Regs->X.Flags.IOPL = 3;
Regs->X.Flags.NT = 0;
Regs->X.Flags.IF = 1;
Regs->X.Flags.TF = 0;
Regs->X.Flags.CF = 0;
ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));
ThunkRegSet.E.EDI = Regs->E.EDI;
ThunkRegSet.E.ESI = Regs->E.ESI;
ThunkRegSet.E.EBP = Regs->E.EBP;
ThunkRegSet.E.EBX = Regs->E.EBX;
ThunkRegSet.E.EDX = Regs->E.EDX;
ThunkRegSet.E.ECX = Regs->E.ECX;
ThunkRegSet.E.EAX = Regs->E.EAX;
ThunkRegSet.E.DS = Regs->E.DS;
ThunkRegSet.E.ES = Regs->E.ES;
CopyMem (&(ThunkRegSet.E.EFLAGS), &(Regs->E.EFlags), sizeof (UINT32));
//
// The call to Legacy16 is a critical section to EFI
//
Eflags = AsmReadEflags ();
if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
DisableInterrupts ();
}
//
// Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.
//
Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259LegacyMode, NULL, NULL);
ASSERT_EFI_ERROR (Status);
Stack16 = (UINT16 *)((UINT8 *) mThunkContext.RealModeBuffer + mThunkContext.RealModeBufferSize - sizeof (UINT16));
Stack16 -= sizeof (ThunkRegSet.E.EFLAGS) / sizeof (UINT16);
CopyMem (Stack16, &ThunkRegSet.E.EFLAGS, sizeof (ThunkRegSet.E.EFLAGS));
ThunkRegSet.E.SS = (UINT16) (((UINTN) Stack16 >> 16) << 12);
ThunkRegSet.E.ESP = (UINT16) (UINTN) Stack16;
ThunkRegSet.E.Eip = (UINT16)((UINT32 *)NULL)[BiosInt];
ThunkRegSet.E.CS = (UINT16)(((UINT32 *)NULL)[BiosInt] >> 16);
mThunkContext.RealModeState = &ThunkRegSet;
AsmThunk16 (&mThunkContext);
//
// Restore protected mode interrupt state
//
Status = BiosDev->Legacy8259->SetMode (BiosDev->Legacy8259, Efi8259ProtectedMode, NULL, NULL);
ASSERT_EFI_ERROR (Status);
//
// End critical section
//
if ((Eflags | EFI_CPU_EFLAGS_IF) != 0) {
EnableInterrupts ();
}
Regs->E.EDI = ThunkRegSet.E.EDI;
Regs->E.ESI = ThunkRegSet.E.ESI;
Regs->E.EBP = ThunkRegSet.E.EBP;
Regs->E.EBX = ThunkRegSet.E.EBX;
Regs->E.EDX = ThunkRegSet.E.EDX;
Regs->E.ECX = ThunkRegSet.E.ECX;
Regs->E.EAX = ThunkRegSet.E.EAX;
Regs->E.SS = ThunkRegSet.E.SS;
Regs->E.CS = ThunkRegSet.E.CS;
Regs->E.DS = ThunkRegSet.E.DS;
Regs->E.ES = ThunkRegSet.E.ES;
CopyMem (&(Regs->E.EFlags), &(ThunkRegSet.E.EFLAGS), sizeof (UINT32));
Ret = (BOOLEAN) (Regs->E.EFlags.CF == 1);
return Ret;
}
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