Use CPUID Leaf 01 to detect support for debug extensions and FXSAVE/FXRESTOR instructions. Do not enable those features in CR4 if they are not supported. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Michael Kinney <michael.d.kinney@intel.com> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17220 6f19259b-4bc3-4df7-8a09-765794883524
		
			
				
	
	
		
			121 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			121 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/** @file
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  Supporting functions for X64 architecture.
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  Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.<BR>
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  This program and the accompanying materials
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  are licensed and made available under the terms and conditions of the BSD License
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  which accompanies this distribution.  The full text of the license may be found at
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  http://opensource.org/licenses/bsd-license.php.
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  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "DebugAgent.h"
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/**
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  Initialize IDT entries to support source level debug.
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**/
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VOID
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InitializeDebugIdt (
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  VOID
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  )
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{
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  IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
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  UINTN                      InterruptHandler;
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  IA32_DESCRIPTOR            IdtDescriptor;
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  UINTN                      Index;
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  UINT16                     CodeSegment;
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  UINT32                     RegEdx;
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  AsmReadIdtr (&IdtDescriptor);
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  //
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  // Use current CS as the segment selector of interrupt gate in IDT
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  //
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  CodeSegment = AsmReadCs ();
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  IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
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  for (Index = 0; Index < 20; Index ++) {
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    if (((PcdGet32 (PcdExceptionsIgnoredByDebugger) & ~(BIT1 | BIT3)) & (1 << Index)) != 0) {
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      //
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      // If the exception is masked to be reserved except for INT1 and INT3, skip it
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      //
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      continue;
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    }
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    InterruptHandler = (UINTN)&Exception0Handle + Index * ExceptionStubHeaderSize;
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    IdtEntry[Index].Bits.OffsetLow       = (UINT16)(UINTN)InterruptHandler;
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    IdtEntry[Index].Bits.OffsetHigh      = (UINT16)((UINTN)InterruptHandler >> 16);
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    IdtEntry[Index].Bits.OffsetUpper     = (UINT32)((UINTN)InterruptHandler >> 32);
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    IdtEntry[Index].Bits.Selector        = CodeSegment;
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    IdtEntry[Index].Bits.GateType        = IA32_IDT_GATE_TYPE_INTERRUPT_32;
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  }
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  InterruptHandler = (UINTN) &TimerInterruptHandle;
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  IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetLow       = (UINT16)(UINTN)InterruptHandler;
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  IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetHigh      = (UINT16)((UINTN)InterruptHandler >> 16);
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  IdtEntry[DEBUG_TIMER_VECTOR].Bits.OffsetUpper     = (UINT32)((UINTN)InterruptHandler >> 32);
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  IdtEntry[DEBUG_TIMER_VECTOR].Bits.Selector        = CodeSegment;
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  IdtEntry[DEBUG_TIMER_VECTOR].Bits.GateType        = IA32_IDT_GATE_TYPE_INTERRUPT_32;
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  //
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  // If the CPU supports Debug Extensions(CPUID:01 EDX:BIT2), then 
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  // Set DE flag in CR4 to enable IO breakpoint
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  //
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  AsmCpuid (1, NULL, NULL, NULL, &RegEdx);
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  if ((RegEdx & BIT2) != 0) {
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    AsmWriteCr4 (AsmReadCr4 () | BIT3);
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  }
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}
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/**
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  Retrieve exception handler from IDT table by ExceptionNum.
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  @param[in]  ExceptionNum    Exception number
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  @return Exception handler
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**/
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VOID *
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GetExceptionHandlerInIdtEntry (
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  IN UINTN             ExceptionNum
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  )
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{
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  IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
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  IA32_DESCRIPTOR            IdtDescriptor;
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  AsmReadIdtr (&IdtDescriptor);
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  IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
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  return (VOID *) (IdtEntry[ExceptionNum].Bits.OffsetLow |
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                  (((UINTN)IdtEntry[ExceptionNum].Bits.OffsetHigh) << 16) |
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                  (((UINTN)IdtEntry[ExceptionNum].Bits.OffsetUpper) << 32));
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} 
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/**
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  Set exception handler in IDT table by ExceptionNum.
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  @param[in]  ExceptionNum      Exception number
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  @param[in]  ExceptionHandler  Exception Handler to be set 
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**/
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VOID
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SetExceptionHandlerInIdtEntry (
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  IN UINTN             ExceptionNum,
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  IN VOID              *ExceptionHandler
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  )
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{
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  IA32_IDT_GATE_DESCRIPTOR   *IdtEntry;
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  IA32_DESCRIPTOR            IdtDescriptor;
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  AsmReadIdtr (&IdtDescriptor);
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  IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor.Base;
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  IdtEntry[ExceptionNum].Bits.OffsetLow   = (UINT16)(UINTN)ExceptionHandler;
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  IdtEntry[ExceptionNum].Bits.OffsetHigh  = (UINT16)((UINTN)ExceptionHandler >> 16);
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  IdtEntry[ExceptionNum].Bits.OffsetUpper = (UINT32)((UINTN)ExceptionHandler >> 32);
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}
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