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/** @file
Supporting functions for X64 architecture.
Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "DebugAgent.h"
/**
Initialize IDT entries to support source level debug.
**/
VOID
InitializeDebugIdt (
VOID
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
UINTN InterruptHandler;
IA32_DESCRIPTOR IdtDescriptor;
UINTN Index;
UINT16 CodeSegment;
UINT32 RegEdx;
AsmReadIdtr (&IdtDescriptor);
//
// Use current CS as the segment selector of interrupt gate in IDT
//
CodeSegment = AsmReadCs ();
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
for (Index = 0; Index < 20; Index ++) {
if (((PcdGet32 (PcdExceptionsIgnoredByDebugger) & ~(BIT1 | BIT3)) & (1 << Index)) != 0) {
//
// If the exception is masked to be reserved except for INT1 and INT3, skip it
//
continue;
}
InterruptHandler = (UINTN)&Exception0Handle + Index * ExceptionStubHeaderSize;
IdtEntry[Index].Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
IdtEntry[Index].Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16);
IdtEntry[Index].Bits.OffsetUpper = (UINT32)((UINTN)InterruptHandler >> 32);
IdtEntry[Index].Bits.Selector = CodeSegment;
IdtEntry[Index].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
}
InterruptHandler = (UINTN) &TimerInterruptHandle;
IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16);
IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetUpper = (UINT32)((UINTN)InterruptHandler >> 32);
IdtEntry[DEBUG_TIMER_VECTOR].Bits.Selector = CodeSegment;
IdtEntry[DEBUG_TIMER_VECTOR].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
//
// If the CPU supports Debug Extensions(CPUID:01 EDX:BIT2), then
// Set DE flag in CR4 to enable IO breakpoint
//
AsmCpuid (1, NULL, NULL, NULL, &RegEdx);
if ((RegEdx & BIT2) != 0) {
AsmWriteCr4 (AsmReadCr4 () | BIT3);
}
}
/**
Retrieve exception handler from IDT table by ExceptionNum.
@param[in] ExceptionNum Exception number
@return Exception handler
**/
VOID *
GetExceptionHandlerInIdtEntry (
IN UINTN ExceptionNum
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
IA32_DESCRIPTOR IdtDescriptor;
AsmReadIdtr (&IdtDescriptor);
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
return (VOID *) (IdtEntry[ExceptionNum].Bits.OffsetLow |
(((UINTN)IdtEntry[ExceptionNum].Bits.OffsetHigh) << 16) |
(((UINTN)IdtEntry[ExceptionNum].Bits.OffsetUpper) << 32));
}
/**
Set exception handler in IDT table by ExceptionNum.
@param[in] ExceptionNum Exception number
@param[in] ExceptionHandler Exception Handler to be set
**/
VOID
SetExceptionHandlerInIdtEntry (
IN UINTN ExceptionNum,
IN VOID *ExceptionHandler
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
IA32_DESCRIPTOR IdtDescriptor;
AsmReadIdtr (&IdtDescriptor);
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
IdtEntry[ExceptionNum].Bits.OffsetLow = (UINT16)(UINTN)ExceptionHandler;
IdtEntry[ExceptionNum].Bits.OffsetHigh = (UINT16)((UINTN)ExceptionHandler >> 16);
IdtEntry[ExceptionNum].Bits.OffsetUpper = (UINT32)((UINTN)ExceptionHandler >> 32);
}
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