summaryrefslogtreecommitdiff
path: root/EmbeddedPkg/GdbStub/Arm/Processor.c
blob: 77ea933977995f687359846351227d88d77c8304 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
/** @file
  Processor specific parts of the GDB stub

  Copyright (c) 2008-2009, Apple Inc. All rights reserved.
  
  All rights reserved. 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.

**/
/** @file
  
  Copyright (c) 2008, Apple, Inc                                                         
  All rights reserved. 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 <GdbStubInternal.h>
#include <Library/CacheMaintenanceLib.h>
#include <Library/PrintLib.h>

//
// 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_SIGEMT  },  
//  { EXCEPT_ARM_RESERVED,              GDB_SIGILL  }  
};

// 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);
}


/**
 Return the number of entries in the gRegisters[]
 
 @retval  UINTN, the number of entries (registers) in the gRegisters[] array.    
 **/
UINTN
MaxRegisterCount (
  VOID
  )
{
  return sizeof (gRegisterOffsets)/sizeof (UINTN);
}


/**
 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;
}


/** ‘p n’ 
 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 >= MaxRegisterCount()) {
    SendError (GDB_EINVALIDREGNUM); 
    return;
  }
  
  OutBufPtr = OutBuffer;
  OutBufPtr = BasicReadRegister (SystemContext, RegNumber, OutBufPtr);
  
  *OutBufPtr = '\0';  // the end of the buffer
  SendPacket(OutBuffer);
}


/** ‘g’ 
 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;
  CHAR8   *OutBuffer;
  CHAR8   *OutBufPtr;
  UINTN   RegisterCount = MaxRegisterCount();
  
  // It is not safe to allocate pool here....
  OutBuffer = AllocatePool((RegisterCount * 8) + 1); // 8 bytes per register in string format plus a null to terminate
  OutBufPtr = OutBuffer;
  for (Index = 0; Index < RegisterCount; Index++) {
    OutBufPtr = BasicReadRegister (SystemContext, Index, OutBufPtr);
  }
  
  *OutBufPtr = '\0';
  SendPacket(OutBuffer);
  FreePool(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 >= MaxRegisterCount()) {
    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 = MaxRegisterCount();

  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 ();
}

// What about Thumb?
// Use SWI 0xdbdbdb as the debug instruction
#define GDB_ARM_BKPT    0xefdbdbdb

BOOLEAN mSingleStepActive = FALSE;
UINT32  mSingleStepPC;
UINT32  mSingleStepData;
UINTN   mSingleStepDataSize;

typedef struct {
  LIST_ENTRY  Link;
  UINT64      Signature;
  UINT32      Address;
  UINT32      Instruction;
} ARM_SOFTWARE_BREAKPOINT;

#define ARM_SOFTWARE_BREAKPOINT_SIGNATURE     SIGNATURE_64('A', 'R', 'M', 'B', 'R', 'K', 'P', 'T')
#define ARM_SOFTWARE_BREAKPOINT_FROM_LINK(a)  CR(a, ARM_SOFTWARE_BREAKPOINT, Link, ARM_SOFTWARE_BREAKPOINT_SIGNATURE)

LIST_ENTRY  BreakpointList;

/** 
 Insert Single Step in the SystemContext
 
 @param	SystemContext	Register content at time of the exception
 **/
VOID
AddSingleStep (
  IN EFI_SYSTEM_CONTEXT SystemContext
  )
{
  if (mSingleStepActive) {
    // Currently don't support nesting
    return;
  }
  mSingleStepActive = TRUE;
  
  mSingleStepPC = SystemContext.SystemContextArm->PC;

  mSingleStepDataSize = sizeof (UINT32);
  mSingleStepData = (*(UINT32 *)mSingleStepPC); 
  *(UINT32 *)mSingleStepPC = GDB_ARM_BKPT;
  if (*(UINT32 *)mSingleStepPC != GDB_ARM_BKPT) {
    // For some reason our breakpoint did not take
    mSingleStepActive = FALSE;
  }

  InvalidateInstructionCacheRange((VOID *)mSingleStepPC, mSingleStepDataSize);
  //DEBUG((EFI_D_ERROR, "AddSingleStep at 0x%08x (was: 0x%08x is:0x%08x)\n", SystemContext.SystemContextArm->PC, mSingleStepData, *(UINT32 *)mSingleStepPC));
}

  
/** 
 Remove Single Step in the SystemContext
 
 @param	SystemContext	Register content at time of the exception
 **/
VOID
RemoveSingleStep (
  IN  EFI_SYSTEM_CONTEXT  SystemContext
  )
{
  if (!mSingleStepActive) {
    return;
  }
  
  if (mSingleStepDataSize == sizeof (UINT16)) {
    *(UINT16 *)mSingleStepPC = (UINT16)mSingleStepData;
  } else {
    //DEBUG((EFI_D_ERROR, "RemoveSingleStep at 0x%08x (was: 0x%08x is:0x%08x)\n", SystemContext.SystemContextArm->PC, *(UINT32 *)mSingleStepPC, mSingleStepData));
    *(UINT32 *)mSingleStepPC = mSingleStepData;
  }
  InvalidateInstructionCacheRange((VOID *)mSingleStepPC, mSingleStepDataSize);
  mSingleStepActive = FALSE;
}



/** ‘c [addr ]’ 
 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();
}

UINTN
GetBreakpointDataAddress (
  IN  EFI_SYSTEM_CONTEXT  SystemContext,
  IN  UINTN               BreakpointNumber
  )
{
  return 0;
}

UINTN
GetBreakpointDetected (
  IN  EFI_SYSTEM_CONTEXT  SystemContext
  )
{
  return 0;
}

BREAK_TYPE
GetBreakpointType (
  IN  EFI_SYSTEM_CONTEXT  SystemContext,
  IN  UINTN               BreakpointNumber
  )
{
  return NotSupported;
}

ARM_SOFTWARE_BREAKPOINT *
SearchBreakpointList (
  IN  UINT32  Address
  )
{
  LIST_ENTRY              *Current;
  ARM_SOFTWARE_BREAKPOINT *Breakpoint;

  Current = GetFirstNode(&BreakpointList);
  while (!IsNull(&BreakpointList, Current)) {
    Breakpoint = ARM_SOFTWARE_BREAKPOINT_FROM_LINK(Current);

    if (Address == Breakpoint->Address) {
      return Breakpoint;
    }

    Current = GetNextNode(&BreakpointList, Current);
  }

  return NULL;
}

VOID
SetBreakpoint (
  IN UINT32 Address
  )
{
  ARM_SOFTWARE_BREAKPOINT *Breakpoint;

  Breakpoint = SearchBreakpointList(Address);

  if (Breakpoint != NULL) {
    return;
  }

  // create and fill breakpoint structure
  Breakpoint = AllocatePool(sizeof(ARM_SOFTWARE_BREAKPOINT));

  Breakpoint->Signature   = ARM_SOFTWARE_BREAKPOINT_SIGNATURE;
  Breakpoint->Address     = Address;
  Breakpoint->Instruction = *(UINT32 *)Address;
  
  // Add it to the list
  InsertTailList(&BreakpointList, &Breakpoint->Link);

  // Insert the software breakpoint
  *(UINT32 *)Address = GDB_ARM_BKPT;
  InvalidateInstructionCacheRange((VOID *)Address, 4);

  //DEBUG((EFI_D_ERROR, "SetBreakpoint at 0x%08x (was: 0x%08x is:0x%08x)\n", Address, Breakpoint->Instruction, *(UINT32 *)Address));
}

VOID
ClearBreakpoint (
  IN UINT32 Address
  )
{
  ARM_SOFTWARE_BREAKPOINT *Breakpoint;

  Breakpoint = SearchBreakpointList(Address);

  if (Breakpoint == NULL) {
    return;
  }

  // Add it to the list
  RemoveEntryList(&Breakpoint->Link);

  // Restore the original instruction
  *(UINT32 *)Address = Breakpoint->Instruction;
  InvalidateInstructionCacheRange((VOID *)Address, 4);

  //DEBUG((EFI_D_ERROR, "ClearBreakpoint at 0x%08x (was: 0x%08x is:0x%08x)\n", Address, GDB_ARM_BKPT, *(UINT32 *)Address));

  FreePool(Breakpoint);
}

VOID
EFIAPI
InsertBreakPoint (
  IN  EFI_SYSTEM_CONTEXT  SystemContext,
  IN  CHAR8              *PacketData
  )
{
  UINTN Type;
  UINTN Address;
  UINTN Length;
  UINTN ErrorCode;

  ErrorCode = ParseBreakpointPacket(PacketData, &Type, &Address, &Length);
  if (ErrorCode > 0) {
    SendError ((UINT8)ErrorCode);
    return;
  }

  switch (Type) {
    case 0:   //Software breakpoint
      break;

    default  :
      DEBUG((EFI_D_ERROR, "Insert breakpoint default: %x\n", Type));
      SendError (GDB_EINVALIDBRKPOINTTYPE);
      return;
  }

  SetBreakpoint(Address);

  SendSuccess ();
}

VOID
EFIAPI
RemoveBreakPoint (
  IN  EFI_SYSTEM_CONTEXT  SystemContext,
  IN  CHAR8               *PacketData
  )
{
  UINTN      Type;
  UINTN      Address;
  UINTN      Length;
  UINTN      ErrorCode;

  //Parse breakpoint packet data
  ErrorCode = ParseBreakpointPacket (PacketData, &Type, &Address, &Length);
  if (ErrorCode > 0) {
    SendError ((UINT8)ErrorCode);
    return;
  }

  switch (Type) {
    case 0:   //Software breakpoint
      break;
    
    default:
      SendError (GDB_EINVALIDBRKPOINTTYPE);
      return;
  }

  ClearBreakpoint(Address);

  SendSuccess ();
}

VOID
InitializeProcessor (
  VOID
  )
{
  // Initialize breakpoint list
  InitializeListHead(&BreakpointList);
}

BOOLEAN
ValidateAddress (
  IN  VOID  *Address
  )
{
  if ((UINT32)Address < 0x80000000) {
    return FALSE;
  } else {
    return TRUE;
  }
}

BOOLEAN
ValidateException (
  IN  EFI_EXCEPTION_TYPE    ExceptionType, 
  IN OUT EFI_SYSTEM_CONTEXT SystemContext 
  )
{
  UINT32  ExceptionAddress;
  UINT32  Instruction;
  
  // Is it a debugger SWI?
  ExceptionAddress = SystemContext.SystemContextArm->PC -= 4;
  Instruction      = *(UINT32 *)ExceptionAddress;
  if (Instruction != GDB_ARM_BKPT) {
    return FALSE;
  }

  // Special for SWI-based exception handling.  SWI sets up the context
  // to return to the instruction following the SWI instruction - NOT what we want
  // for a debugger!
  SystemContext.SystemContextArm->PC = ExceptionAddress;

  return TRUE;
}