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0a90065ac9
When we die due to a fatal exception, we get a debug message that looks like this: Exception #6 from 0x0010:0x000728E9 !!! This message by itself is not incredibly useful for figuring out which code caused the exception. This patch borrows an idea from the Linux kernel, and extends the exception information with a dump of the opcode bytes around the instruction pointer, which means that the exception debug message will now look like this: Exception #6 from 0x0010:0x000728E9 !!! 000728C9: 07 00 6A 40 E8 E0 E8 FF-FF 83 C4 0C 68 00 00 07 [...] 000728D9: 00 68 DA 3A 07 00 6A 40-E8 CC E8 FF FF 83 C4 10 [...] 000728E9: 0F 0B E8 8E F2 FF FF 8D-55 98 80 78 0E 01 8D 45 [...] 000728F9: 94 75 06 52 50 6A 01 EB-04 52 50 6A 00 68 53 47 [...] Tested by inserting a UD2 instruction into Stage1A and verifying on qemu ia32 and on qemu x64 that the right information is printed. Signed-off-by: Lennert Buytenhek <buytenh@arista.com>
111 lines
3.0 KiB
C
111 lines
3.0 KiB
C
/** @file
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X64 CPU Exception Handler functons.
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Copyright (c) 2012 - 2020, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <CpuExceptionCommon.h>
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CONST UINT32 mErrorCodeFlag = 0x00027d00;
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/**
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Common exception handler.
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It will print out the location where exception occured and then halt the system.
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This function will never return.
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@param[in] Stack Current stack address pointer.
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@param[in] ExceptionType Exception type code.
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**/
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VOID
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EFIAPI
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CommonExceptionHandler (
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IN UINTN *Stack,
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IN UINT8 ExceptionType
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)
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{
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UINTN *Ptr;
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// Skip the ExceptionType on the stack
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Ptr = Stack + 1;
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// Skip the ErrorCode on the stack
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if (ExceptionType < CPU_EXCEPTION_NUM) {
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if (mErrorCodeFlag & (1 << ExceptionType)) {
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Ptr++;
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}
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}
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DEBUG ((DEBUG_ERROR, "Exception #%d from 0x%04X:0x%08X !!!\n", ExceptionType, (UINT32)Ptr[1], (UINT32)Ptr[0]));
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DumpHex(0, Ptr[0] - 32, 64, (UINT8 *)(Ptr[0] - 32));
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CpuHalt (NULL);
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}
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/**
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Update exception handler in IDT table .
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This function is used to update the IDT exception handler with current stage.
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@param[in] IdtDescritor If non-zero, it is new IDT descriptor to be updated.
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if it is 0, the IDT descriptor will be retrieved from IDT base register.
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**/
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VOID
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EFIAPI
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UpdateExceptionHandler2 (
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IN VOID *IdtDescriptor
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)
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{
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IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
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VOID *InterruptHandler;
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UINT32 Index;
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IA32_DESCRIPTOR Idtr;
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EXCEPTION_HANDLER_TEMPLATE_MAP TemplateMap;
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UINT16 Cs;
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if (IdtDescriptor == NULL) {
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AsmReadIdtr (&Idtr);
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} else {
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Idtr = *(IA32_DESCRIPTOR *) IdtDescriptor;
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}
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Cs = AsmReadCs ();
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AsmGetTemplateAddressMap (&TemplateMap);
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IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *)Idtr.Base;
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for (Index = 0; Index < CPU_EXCEPTION_NUM; Index ++) {
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InterruptHandler = (VOID *)(UINTN)(TemplateMap.ExceptionStart + TemplateMap.ExceptionStubHeaderSize * Index);
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IdtEntry->Uint128.Uint64 = 0;
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IdtEntry->Uint128.Uint64_1 = 0;
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IdtEntry->Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
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IdtEntry->Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16);
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IdtEntry->Bits.OffsetUpper = (UINT32)((UINTN)InterruptHandler >> 32);
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IdtEntry->Bits.Selector = Cs;
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IdtEntry->Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
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IdtEntry++;
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}
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if (IdtDescriptor != NULL) {
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AsmWriteIdtr (&Idtr);
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}
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}
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/**
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Update exception handler in IDT table .
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This function is used to update the IDT exception handler with current stage.
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@param[in] IdtDescriptor If not NULL, it is new IDT descriptor to be updated.
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if it is NULL, the IDT descriptor will be retrieved from IDT base register.
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**/
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VOID
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UpdateExceptionHandler (
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IN IA32_DESCRIPTOR *IdtDescriptor
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)
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{
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UpdateDebugAgentIdt (IdtDescriptor, UpdateExceptionHandler2);
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}
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