/** @file
Processor specific parts of the GDB stub
Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <GdbDebugAgent.h>
#include <Library/PrintLib.h>
#include <Library/ArmLib.h>
//
// Externs from the exception handler assembly file
//
VOID
ExceptionHandlersStart (
VOID
);
VOID
ExceptionHandlersEnd (
VOID
);
VOID
CommonExceptionEntry (
VOID
);
VOID
AsmCommonExceptionEntry (
VOID
);
//
// Array of exception types that need to be hooked by the debugger
// (efi, gdb) //efi number
//
EFI_EXCEPTION_TYPE_ENTRY gExceptionType[] = {
{ EXCEPT_ARM_SOFTWARE_INTERRUPT, GDB_SIGTRAP },
{ EXCEPT_ARM_UNDEFINED_INSTRUCTION, GDB_SIGTRAP },
{ EXCEPT_ARM_PREFETCH_ABORT, GDB_SIGTRAP },
{ EXCEPT_ARM_DATA_ABORT, GDB_SIGTRAP }, // GDB_SIGEMT
{ EXCEPT_ARM_RESERVED, GDB_SIGTRAP }, // GDB_SIGILL
{ EXCEPT_ARM_FIQ, GDB_SIGINT } // Used for ctrl-c
};
// Shut up some annoying RVCT warnings
#ifdef __CC_ARM
#pragma diag_suppress 1296
#endif
UINTN gRegisterOffsets[] = {
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R0),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R1),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R2),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R3),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R4),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R5),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R6),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R7),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R8),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R9),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R10),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R11),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, R12),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, SP),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, LR),
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, PC),
0x00000F01, // f0
0x00000F02,
0x00000F03,
0x00000F11, // f1
0x00000F12,
0x00000F13,
0x00000F21, // f2
0x00000F22,
0x00000F23,
0x00000F31, // f3
0x00000F32,
0x00000F33,
0x00000F41, // f4
0x00000F42,
0x00000F43,
0x00000F51, // f5
0x00000F52,
0x00000F53,
0x00000F61, // f6
0x00000F62,
0x00000F63,
0x00000F71, // f7
0x00000F72,
0x00000F73,
0x00000FFF, // fps
OFFSET_OF(EFI_SYSTEM_CONTEXT_ARM, CPSR)
};
// restore warnings for RVCT
#ifdef __CC_ARM
#pragma diag_default 1296
#endif
/**
Return the number of entries in the gExceptionType[]
@retval UINTN, the number of entries in the gExceptionType[] array.
**/
UINTN
MaxEfiException (
VOID
)
{
return sizeof (gExceptionType)/sizeof (EFI_EXCEPTION_TYPE_ENTRY);
}
/**
Check to see if the ISA is supported.
ISA = Instruction Set Architecture
@retval TRUE if Isa is supported
**/
BOOLEAN
CheckIsa (
IN EFI_INSTRUCTION_SET_ARCHITECTURE Isa
)
{
if (Isa == IsaArm) {
return TRUE;
} else {
return FALSE;
}
}
/**
This takes in the register number and the System Context, and returns a pointer to the RegNumber-th register in gdb ordering
It is, by default, set to find the register pointer of the ARM member
@param SystemContext Register content at time of the exception
@param RegNumber The register to which we want to find a pointer
@retval the pointer to the RegNumber-th pointer
**/
UINTN *
FindPointerToRegister(
IN EFI_SYSTEM_CONTEXT SystemContext,
IN UINTN RegNumber
)
{
UINT8 *TempPtr;
ASSERT(gRegisterOffsets[RegNumber] < 0xF00);
TempPtr = ((UINT8 *)SystemContext.SystemContextArm) + gRegisterOffsets[RegNumber];
return (UINT32 *)TempPtr;
}
/**
Adds the RegNumber-th register's value to the output buffer, starting at the given OutBufPtr
@param SystemContext Register content at time of the exception
@param RegNumber the number of the register that we want to read
@param OutBufPtr pointer to the output buffer's end. the new data will be added from this point on.
@retval the pointer to the next character of the output buffer that is available to be written on.
**/
CHAR8 *
BasicReadRegister (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN UINTN RegNumber,
IN CHAR8 *OutBufPtr
)
{
UINTN RegSize;
CHAR8 Char;
if (gRegisterOffsets[RegNumber] > 0xF00) {
AsciiSPrint(OutBufPtr, 9, "00000000");
OutBufPtr += 8;
return OutBufPtr;
}
RegSize = 0;
while (RegSize < 32) {
Char = mHexToStr[(UINT8)((*FindPointerToRegister(SystemContext, RegNumber) >> (RegSize+4)) & 0xf)];
if ((Char >= 'A') && (Char <= 'F')) {
Char = Char - 'A' + 'a';
}
*OutBufPtr++ = Char;
Char = mHexToStr[(UINT8)((*FindPointerToRegister(SystemContext, RegNumber) >> RegSize) & 0xf)];
if ((Char >= 'A') && (Char <= 'F')) {
Char = Char - 'A' + 'a';
}
*OutBufPtr++ = Char;
RegSize = RegSize + 8;
}
return OutBufPtr;
}
/**
Reads the n-th register's value into an output buffer and sends it as a packet
@param SystemContext Register content at time of the exception
@param InBuffer Pointer to the input buffer received from gdb server
**/
VOID
ReadNthRegister (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *InBuffer
)
{
UINTN RegNumber;
CHAR8 OutBuffer[9]; // 1 reg=8 hex chars, and the end '\0' (escape seq)
CHAR8 *OutBufPtr; // pointer to the output buffer
RegNumber = AsciiStrHexToUintn (&InBuffer[1]);
if (RegNumber >= (sizeof (gRegisterOffsets)/sizeof (UINTN))) {
SendError (GDB_EINVALIDREGNUM);
return;
}
OutBufPtr = OutBuffer;
OutBufPtr = BasicReadRegister (SystemContext, RegNumber, OutBufPtr);
*OutBufPtr = '\0'; // the end of the buffer
SendPacket(OutBuffer);
}
/**
Reads the general registers into an output buffer and sends it as a packet
@param SystemContext Register content at time of the exception
**/
VOID
EFIAPI
ReadGeneralRegisters (
IN EFI_SYSTEM_CONTEXT SystemContext
)
{
UINTN Index;
// a UINT32 takes 8 ascii characters
CHAR8 OutBuffer[(sizeof (gRegisterOffsets) * 2) + 1];
CHAR8 *OutBufPtr;
// It is not safe to allocate pool here....
OutBufPtr = OutBuffer;
for (Index = 0; Index < (sizeof (gRegisterOffsets)/sizeof (UINTN)); Index++) {
OutBufPtr = BasicReadRegister (SystemContext, Index, OutBufPtr);
}
*OutBufPtr = '\0';
SendPacket(OutBuffer);
}
/**
Adds the RegNumber-th register's value to the output buffer, starting at the given OutBufPtr
@param SystemContext Register content at time of the exception
@param RegNumber the number of the register that we want to write
@param InBufPtr pointer to the output buffer. the new data will be extracted from the input buffer from this point on.
@retval the pointer to the next character of the input buffer that can be used
**/
CHAR8 *
BasicWriteRegister (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN UINTN RegNumber,
IN CHAR8 *InBufPtr
)
{
UINTN RegSize;
UINTN TempValue; // the value transferred from a hex char
UINT32 NewValue; // the new value of the RegNumber-th Register
if (gRegisterOffsets[RegNumber] > 0xF00) {
return InBufPtr + 8;
}
NewValue = 0;
RegSize = 0;
while (RegSize < 32) {
TempValue = HexCharToInt(*InBufPtr++);
if ((INTN)TempValue < 0) {
SendError (GDB_EBADMEMDATA);
return NULL;
}
NewValue += (TempValue << (RegSize+4));
TempValue = HexCharToInt(*InBufPtr++);
if ((INTN)TempValue < 0) {
SendError (GDB_EBADMEMDATA);
return NULL;
}
NewValue += (TempValue << RegSize);
RegSize = RegSize + 8;
}
*(FindPointerToRegister(SystemContext, RegNumber)) = NewValue;
return InBufPtr;
}
/** ‘P n...=r...’
Writes the new value of n-th register received into the input buffer to the n-th register
@param SystemContext Register content at time of the exception
@param InBuffer Ponter to the input buffer received from gdb server
**/
VOID
WriteNthRegister (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *InBuffer
)
{
UINTN RegNumber;
CHAR8 RegNumBuffer[MAX_REG_NUM_BUF_SIZE]; // put the 'n..' part of the message into this array
CHAR8 *RegNumBufPtr;
CHAR8 *InBufPtr; // pointer to the input buffer
// find the register number to write
InBufPtr = &InBuffer[1];
RegNumBufPtr = RegNumBuffer;
while (*InBufPtr != '=') {
*RegNumBufPtr++ = *InBufPtr++;
}
*RegNumBufPtr = '\0';
RegNumber = AsciiStrHexToUintn (RegNumBuffer);
// check if this is a valid Register Number
if (RegNumber >= (sizeof (gRegisterOffsets)/sizeof (UINTN))) {
SendError (GDB_EINVALIDREGNUM);
return;
}
InBufPtr++; // skips the '=' character
BasicWriteRegister (SystemContext, RegNumber, InBufPtr);
SendSuccess();
}
/** ‘G XX...’
Writes the new values received into the input buffer to the general registers
@param SystemContext Register content at time of the exception
@param InBuffer Pointer to the input buffer received from gdb server
**/
VOID
EFIAPI
WriteGeneralRegisters (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *InBuffer
)
{
UINTN i;
CHAR8 *InBufPtr; /// pointer to the input buffer
UINTN MinLength;
UINTN RegisterCount = (sizeof (gRegisterOffsets)/sizeof (UINTN));
MinLength = (RegisterCount * 8) + 1; // 'G' plus the registers in ASCII format
if (AsciiStrLen(InBuffer) < MinLength) {
//Bad message. Message is not the right length
SendError (GDB_EBADBUFSIZE);
return;
}
InBufPtr = &InBuffer[1];
// Read the new values for the registers from the input buffer to an array, NewValueArray.
// The values in the array are in the gdb ordering
for(i = 0; i < RegisterCount; i++) {
InBufPtr = BasicWriteRegister (SystemContext, i, InBufPtr);
}
SendSuccess ();
}
/**
Continue. addr is Address to resume. If addr is omitted, resume at current
Address.
@param SystemContext Register content at time of the exception
**/
VOID
EFIAPI
ContinueAtAddress (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *PacketData
)
{
if (PacketData[1] != '\0') {
SystemContext.SystemContextArm->PC = AsciiStrHexToUintn(&PacketData[1]);
}
}
/** ‘s [addr ]’
Single step. addr is the Address at which to resume. If addr is omitted, resume
at same Address.
@param SystemContext Register content at time of the exception
**/
VOID
EFIAPI
SingleStep (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *PacketData
)
{
SendNotSupported();
}
VOID
EFIAPI
InsertBreakPoint (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *PacketData
)
{
SendNotSupported ();
}
VOID
EFIAPI
RemoveBreakPoint (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN CHAR8 *PacketData
)
{
SendNotSupported ();
}
/**
Send the T signal with the given exception type (in gdb order) and possibly
with n:r pairs related to the watchpoints
@param SystemContext Register content at time of the exception
@param GdbExceptionType GDB exception type
**/
VOID
ProcessorSendTSignal (
IN EFI_SYSTEM_CONTEXT SystemContext,
IN UINT8 GdbExceptionType,
IN OUT CHAR8 *TSignalPtr,
IN UINTN SizeOfBuffer
)
{
*TSignalPtr = '\0';
}
/**
FIQ state is only changed by FIQ exception. We don't want to take FIQ
ticks in the GDB stub. The stub disables FIQ on entry, but this is the
third instruction that executes in the execption handler. Thus we have
a crack we need to test for.
@param PC PC of execption
@return TRUE We are in the GDB stub exception preamble
@return FALSE We are not in GDB stub code
**/
BOOLEAN
InFiqCrack (
IN UINT32 PC
)
{
UINT64 VectorBase = PcdGet64 (PcdCpuVectorBaseAddress);
UINT32 Length = (UINTN)ExceptionHandlersEnd - (UINTN)ExceptionHandlersStart;
if ((PC >= VectorBase) && (PC <= (VectorBase + Length))) {
return TRUE;
}
return FALSE;
}
/**
Check to see if this exception is related to ctrl-c handling.
In this scheme we dedicate FIQ to the ctrl-c handler so it is
independent of the rest of the system.
SaveAndSetDebugTimerInterrupt () can be used to
@param ExceptionType Exception that is being processed
@param SystemContext Register content at time of the exception
@return TRUE This was a ctrl-c check that did not find a ctrl-c
@return FALSE This was not a ctrl-c check or some one hit ctrl-c
**/
BOOLEAN
ProcessorControlC (
IN EFI_EXCEPTION_TYPE ExceptionType,
IN OUT EFI_SYSTEM_CONTEXT SystemContext
)
{
CHAR8 Char;
BOOLEAN Return = TRUE;
if (ExceptionType != EXCEPT_ARM_FIQ) {
// Skip it as it is not related to ctrl-c
return FALSE;
}
if (InFiqCrack (SystemContext.SystemContextArm->PC)) {
// We are in our own interrupt preable, so skip this tick.
// We never want to let gdb see the debug stub running if we can help it
return FALSE;
}
while (TRUE) {
if (!GdbIsCharAvailable ()) {
//
// No characters are pending so exit the loop
//
Return = TRUE;
break;
}
Char = GdbGetChar ();
if (Char == 0x03) {
//
// We have a ctrl-c so exit and process exception for ctrl-c
//
Return = FALSE;
break;
}
}
DebugAgentTimerEndOfInterrupt ();
// Force an exit from the exception handler as we are done
return Return;
}
/**
Enable/Disable the interrupt of debug timer and return the interrupt state
prior to the operation.
If EnableStatus is TRUE, enable the interrupt of debug timer.
If EnableStatus is FALSE, disable the interrupt of debug timer.
@param[in] EnableStatus Enable/Disable.
@retval TRUE Debug timer interrupt were enabled on entry to this call.
@retval FALSE Debug timer interrupt were disabled on entry to this call.
**/
BOOLEAN
EFIAPI
SaveAndSetDebugTimerInterrupt (
IN BOOLEAN EnableStatus
)
{
BOOLEAN FiqEnabled;
FiqEnabled = ArmGetFiqState ();
if (EnableStatus) {
DebugAgentTimerSetPeriod (PcdGet32 (PcdGdbTimerPeriodMilliseconds));
ArmEnableFiq ();
} else {
DebugAgentTimerSetPeriod (0);
ArmDisableFiq ();
}
return FiqEnabled;
}
VOID
GdbFPutString (
IN CHAR8 *String
);
/**
Initialize debug agent.
This function is used to set up debug environment to support source level debugging.
If certain Debug Agent Library instance has to save some private data in the stack,
this function must work on the mode that doesn't return to the caller, then
the caller needs to wrap up all rest of logic after InitializeDebugAgent() into one
function and pass it into InitializeDebugAgent(). InitializeDebugAgent() is
responsible to invoke the passing-in function at the end of InitializeDebugAgent().
If the parameter Function is not NULL, Debug Agent Library instance will invoke it by
passing in the Context to be its parameter.
If Function() is NULL, Debug Agent Library instance will return after setup debug
environment.
@param[in] InitFlag Init flag is used to decide the initialize process.
@param[in] Context Context needed according to InitFlag; it was optional.
@param[in] Function Continue function called by debug agent library; it was
optional.
**/
VOID
EFIAPI
InitializeDebugAgent (
IN UINT32 InitFlag,
IN VOID *Context, OPTIONAL
IN DEBUG_AGENT_CONTINUE Function OPTIONAL
)
{
UINTN Offset;
UINTN Length;
BOOLEAN IrqEnabled;
UINT64 *VectorBase;
//
// Disable interrupts
//
IrqEnabled = ArmGetInterruptState ();
ArmDisableInterrupts ();
ArmDisableFiq ();
//
// Copy an implementation of the ARM exception vectors to PcdCpuVectorBaseAddress.
//
Length = (UINTN)ExceptionHandlersEnd - (UINTN)ExceptionHandlersStart;
//
// Reserve space for the exception handlers
//
VectorBase = (UINT64 *)(UINTN)PcdGet64 (PcdCpuVectorBaseAddress);
// Copy our assembly code into the page that contains the exception vectors.
CopyMem ((VOID *)VectorBase, (VOID *)ExceptionHandlersStart, Length);
//
// Patch in the common Assembly exception handler
//
Offset = (UINTN)CommonExceptionEntry - (UINTN)ExceptionHandlersStart;
*(UINTN *) (((UINT8 *)VectorBase) + Offset) = (UINTN)AsmCommonExceptionEntry;
// Flush Caches since we updated executable stuff
InvalidateInstructionCacheRange ((VOID *)(UINTN)PcdGet64(PcdCpuVectorBaseAddress), Length);
// setup a timer so gdb can break in via ctrl-c
DebugAgentTimerIntialize ();
if (IrqEnabled) {
ArmEnableInterrupts ();
}
if (Function != NULL) {
Function (Context);
}
return;
}