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