ArmPkg/Library/DefaultExceptionHandlerLib/Arm/DefaultExceptionHandler.c

   1 /** @file
   2   Default exception handler
   3
   4   Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
   5   Copyright (c) 2012 - 2021, Arm Ltd. All rights reserved.<BR>
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10
  11 #include <Uefi.h>
  12 #include <Library/BaseLib.h>
  13 #include <Library/DebugLib.h>
  14 #include <Library/PeCoffGetEntryPointLib.h>
  15 #include <Library/PrintLib.h>
  16 #include <Library/ArmDisassemblerLib.h>
  17 #include <Library/SerialPortLib.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19 #include <Library/UefiLib.h>
  20
  21 #include <Guid/DebugImageInfoTable.h>
  22
  23 #include <Protocol/DebugSupport.h>
  24 #include <Library/DefaultExceptionHandlerLib.h>
  25
  26 //
  27 // The number of elements in a CHAR8 array, including the terminating NUL, that
  28 // is meant to hold the string rendering of the CPSR.
  29 //
  30 #define CPSR_STRING_SIZE  32
  31
  32 typedef struct {
  33   UINT32    BIT;
  34   CHAR8     Char;
  35 } CPSR_CHAR;
  36
  37 STATIC CONST CPSR_CHAR  mCpsrChar[] = {
  38   { 31, 'n' },
  39   { 30, 'z' },
  40   { 29, 'c' },
  41   { 28, 'v' },
  42
  43   { 9,  'e' },
  44   { 8,  'a' },
  45   { 7,  'i' },
  46   { 6,  'f' },
  47   { 5,  't' },
  48   { 0,  '?' }
  49 };
  50
  51 CHAR8 *
  52 GetImageName (
  53   IN  UINTN  FaultAddress,
  54   OUT UINTN  *ImageBase,
  55   OUT UINTN  *PeCoffSizeOfHeaders
  56   );
  57
  58 /**
  59   Convert the Current Program Status Register (CPSR) to a string. The string is
  60   a defacto standard in the ARM world.
  61
  62   It is possible to add extra bits by adding them to mCpsrChar array.
  63
  64   @param  Cpsr         ARM CPSR register value
  65   @param  ReturnStr    CPSR_STRING_SIZE byte string that contains string
  66                        version of CPSR
  67
  68 **/
  69 VOID
  70 CpsrString (
  71   IN  UINT32  Cpsr,
  72   OUT CHAR8   *ReturnStr
  73   )
  74 {
  75   UINTN  Index;
  76   CHAR8  *Str;
  77   CHAR8  *ModeStr;
  78
  79   Str = ReturnStr;
  80
  81   for (Index = 0; mCpsrChar[Index].BIT != 0; Index++, Str++) {
  82     *Str = mCpsrChar[Index].Char;
  83     if ((Cpsr & (1 << mCpsrChar[Index].BIT)) != 0) {
  84       // Concert to upper case if bit is set
  85       *Str &= ~0x20;
  86     }
  87   }
  88
  89   *Str++ = '_';
  90   *Str   = '\0';
  91
  92   switch (Cpsr & 0x1f) {
  93     case 0x10:
  94       ModeStr = "usr";
  95       break;
  96     case 0x011:
  97       ModeStr = "fiq";
  98       break;
  99     case 0x12:
 100       ModeStr = "irq";
 101       break;
 102     case 0x13:
 103       ModeStr = "svc";
 104       break;
 105     case 0x16:
 106       ModeStr = "mon";
 107       break;
 108     case 0x17:
 109       ModeStr = "abt";
 110       break;
 111     case 0x1b:
 112       ModeStr = "und";
 113       break;
 114     case 0x1f:
 115       ModeStr = "sys";
 116       break;
 117
 118     default:
 119       ModeStr = "???";
 120       break;
 121   }
 122
 123   //
 124   // See the interface contract in the leading comment block.
 125   //
 126   AsciiStrCatS (Str, CPSR_STRING_SIZE - (Str - ReturnStr), ModeStr);
 127 }
 128
 129 CHAR8 *
 130 FaultStatusToString (
 131   IN  UINT32  Status
 132   )
 133 {
 134   CHAR8  *FaultSource;
 135
 136   switch (Status) {
 137     case 0x01: FaultSource = "Alignment fault";
 138       break;
 139     case 0x02: FaultSource = "Debug event fault";
 140       break;
 141     case 0x03: FaultSource = "Access Flag fault on Section";
 142       break;
 143     case 0x04: FaultSource = "Cache maintenance operation fault[2]";
 144       break;
 145     case 0x05: FaultSource = "Translation fault on Section";
 146       break;
 147     case 0x06: FaultSource = "Access Flag fault on Page";
 148       break;
 149     case 0x07: FaultSource = "Translation fault on Page";
 150       break;
 151     case 0x08: FaultSource = "Precise External Abort";
 152       break;
 153     case 0x09: FaultSource = "Domain fault on Section";
 154       break;
 155     case 0x0b: FaultSource = "Domain fault on Page";
 156       break;
 157     case 0x0c: FaultSource = "External abort on translation, first level";
 158       break;
 159     case 0x0d: FaultSource = "Permission fault on Section";
 160       break;
 161     case 0x0e: FaultSource = "External abort on translation, second level";
 162       break;
 163     case 0x0f: FaultSource = "Permission fault on Page";
 164       break;
 165     case 0x16: FaultSource = "Imprecise External Abort";
 166       break;
 167     default:   FaultSource = "No function";
 168       break;
 169   }
 170
 171   return FaultSource;
 172 }
 173
 174 STATIC CHAR8  *gExceptionTypeString[] = {
 175   "Reset",
 176   "Undefined OpCode",
 177   "SVC",
 178   "Prefetch Abort",
 179   "Data Abort",
 180   "Undefined",
 181   "IRQ",
 182   "FIQ"
 183 };
 184
 185 /**
 186   This is the default action to take on an unexpected exception
 187
 188   Since this is exception context don't do anything crazy like try to allocate memory.
 189
 190   @param  ExceptionType    Type of the exception
 191   @param  SystemContext    Register state at the time of the Exception
 192
 193
 194 **/
 195 VOID
 196 DefaultExceptionHandler (
 197   IN     EFI_EXCEPTION_TYPE  ExceptionType,
 198   IN OUT EFI_SYSTEM_CONTEXT  SystemContext
 199   )
 200 {
 201   CHAR8    Buffer[100];
 202   UINTN    CharCount;
 203   UINT32   DfsrStatus;
 204   UINT32   IfsrStatus;
 205   BOOLEAN  DfsrWrite;
 206   UINT32   PcAdjust;
 207
 208   PcAdjust = 0;
 209
 210   CharCount = AsciiSPrint (
 211                 Buffer,
 212                 sizeof (Buffer),
 213                 "\n%a Exception PC at 0x%08x  CPSR 0x%08x ",
 214                 gExceptionTypeString[ExceptionType],
 215                 SystemContext.SystemContextArm->PC,
 216                 SystemContext.SystemContextArm->CPSR
 217                 );
 218   SerialPortWrite ((UINT8 *)Buffer, CharCount);
 219   if (gST->ConOut != NULL) {
 220     AsciiPrint (Buffer);
 221   }
 222
 223   DEBUG_CODE_BEGIN ();
 224   CHAR8   *Pdb;
 225   UINT32  ImageBase;
 226   UINT32  PeCoffSizeOfHeader;
 227   UINT32  Offset;
 228   CHAR8   CpsrStr[CPSR_STRING_SIZE];    // char per bit. Lower 5-bits are mode
 229                                         // that is a 3 char string
 230   CHAR8   Buffer[80];
 231   UINT8   *DisAsm;
 232   UINT32  ItBlock;
 233
 234   CpsrString (SystemContext.SystemContextArm->CPSR, CpsrStr);
 235   DEBUG ((DEBUG_ERROR, "%a\n", CpsrStr));
 236
 237   Pdb    = GetImageName (SystemContext.SystemContextArm->PC, &ImageBase, &PeCoffSizeOfHeader);
 238   Offset = SystemContext.SystemContextArm->PC - ImageBase;
 239   if (Pdb != NULL) {
 240     DEBUG ((DEBUG_ERROR, "%a\n", Pdb));
 241
 242     //
 243     // A PE/COFF image loads its headers into memory so the headers are
 244     // included in the linked addresses. ELF and Mach-O images do not
 245     // include the headers so the first byte of the image is usually
 246     // text (code). If you look at link maps from ELF or Mach-O images
 247     // you need to subtract out the size of the PE/COFF header to get
 248     // get the offset that matches the link map.
 249     //
 250     DEBUG ((DEBUG_ERROR, "loaded at 0x%08x (PE/COFF offset) 0x%x (ELF or Mach-O offset) 0x%x", ImageBase, Offset, Offset - PeCoffSizeOfHeader));
 251
 252     // If we come from an image it is safe to show the instruction. We know it should not fault
 253     DisAsm  = (UINT8 *)(UINTN)SystemContext.SystemContextArm->PC;
 254     ItBlock = 0;
 255     DisassembleInstruction (&DisAsm, (SystemContext.SystemContextArm->CPSR & BIT5) == BIT5, TRUE, &ItBlock, Buffer, sizeof (Buffer));
 256     DEBUG ((DEBUG_ERROR, "\n%a", Buffer));
 257
 258     switch (ExceptionType) {
 259       case EXCEPT_ARM_UNDEFINED_INSTRUCTION:
 260       case EXCEPT_ARM_SOFTWARE_INTERRUPT:
 261       case EXCEPT_ARM_PREFETCH_ABORT:
 262       case EXCEPT_ARM_DATA_ABORT:
 263         // advance PC past the faulting instruction
 264         PcAdjust = (UINTN)DisAsm - SystemContext.SystemContextArm->PC;
 265         break;
 266
 267       default:
 268         break;
 269     }
 270   }
 271
 272   DEBUG_CODE_END ();
 273   DEBUG ((DEBUG_ERROR, "\n  R0 0x%08x   R1 0x%08x   R2 0x%08x   R3 0x%08x\n", SystemContext.SystemContextArm->R0, SystemContext.SystemContextArm->R1, SystemContext.SystemContextArm->R2, SystemContext.SystemContextArm->R3));
 274   DEBUG ((DEBUG_ERROR, "  R4 0x%08x   R5 0x%08x   R6 0x%08x   R7 0x%08x\n", SystemContext.SystemContextArm->R4, SystemContext.SystemContextArm->R5, SystemContext.SystemContextArm->R6, SystemContext.SystemContextArm->R7));
 275   DEBUG ((DEBUG_ERROR, "  R8 0x%08x   R9 0x%08x  R10 0x%08x  R11 0x%08x\n", SystemContext.SystemContextArm->R8, SystemContext.SystemContextArm->R9, SystemContext.SystemContextArm->R10, SystemContext.SystemContextArm->R11));
 276   DEBUG ((DEBUG_ERROR, " R12 0x%08x   SP 0x%08x   LR 0x%08x   PC 0x%08x\n", SystemContext.SystemContextArm->R12, SystemContext.SystemContextArm->SP, SystemContext.SystemContextArm->LR, SystemContext.SystemContextArm->PC));
 277   DEBUG ((DEBUG_ERROR, "DFSR 0x%08x DFAR 0x%08x IFSR 0x%08x IFAR 0x%08x\n", SystemContext.SystemContextArm->DFSR, SystemContext.SystemContextArm->DFAR, SystemContext.SystemContextArm->IFSR, SystemContext.SystemContextArm->IFAR));
 278
 279   // Bit10 is Status[4] Bit3:0 is Status[3:0]
 280   DfsrStatus = (SystemContext.SystemContextArm->DFSR & 0xf) | ((SystemContext.SystemContextArm->DFSR >> 6) & 0x10);
 281   DfsrWrite  = (SystemContext.SystemContextArm->DFSR & BIT11) != 0;
 282   if (DfsrStatus != 0x00) {
 283     DEBUG ((DEBUG_ERROR, " %a: %a 0x%08x\n", FaultStatusToString (DfsrStatus), DfsrWrite ? "write to" : "read from", SystemContext.SystemContextArm->DFAR));
 284   }
 285
 286   IfsrStatus = (SystemContext.SystemContextArm->IFSR & 0xf) | ((SystemContext.SystemContextArm->IFSR >> 6) & 0x10);
 287   if (IfsrStatus != 0) {
 288     DEBUG ((DEBUG_ERROR, " Instruction %a at 0x%08x\n", FaultStatusToString (SystemContext.SystemContextArm->IFSR & 0xf), SystemContext.SystemContextArm->IFAR));
 289   }
 290
 291   DEBUG ((DEBUG_ERROR, "\n"));
 292   ASSERT (FALSE);
 293
 294   CpuDeadLoop ();   // may return if executing under a debugger
 295
 296   // Clear the error registers that we have already displayed incase some one wants to keep going
 297   SystemContext.SystemContextArm->DFSR = 0;
 298   SystemContext.SystemContextArm->IFSR = 0;
 299
 300   // If some one is stepping past the exception handler adjust the PC to point to the next instruction
 301   SystemContext.SystemContextArm->PC += PcAdjust;
 302 }