1 /* 2 * linux/arch/powerpc/kernel/traps.c 3 * 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * 6 * Modified by Cort Dougan (cort@cs.nmt.edu) 7 * and Paul Mackerras (paulus@cs.anu.edu.au) 8 * 9 * (C) Copyright 2000 10 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 11 * 12 * SPDX-License-Identifier: GPL-2.0+ 13 */ 14 15 /* 16 * This file handles the architecture-dependent parts of hardware exceptions 17 */ 18 19 #include <common.h> 20 #include <command.h> 21 #include <kgdb.h> 22 #include <asm/processor.h> 23 24 #if defined(CONFIG_CMD_BEDBUG) 25 extern void do_bedbug_breakpoint(struct pt_regs *); 26 #endif 27 28 /* Returns 0 if exception not found and fixup otherwise. */ 29 extern unsigned long search_exception_table(unsigned long); 30 31 /* THIS NEEDS CHANGING to use the board info structure. 32 */ 33 #define END_OF_MEM 0x02000000 34 35 /* 36 * Trap & Exception support 37 */ 38 39 static void print_backtrace(unsigned long *sp) 40 { 41 int cnt = 0; 42 unsigned long i; 43 44 printf("Call backtrace: "); 45 while (sp) { 46 if ((uint)sp > END_OF_MEM) 47 break; 48 49 i = sp[1]; 50 if (cnt++ % 7 == 0) 51 printf("\n"); 52 printf("%08lX ", i); 53 if (cnt > 32) break; 54 sp = (unsigned long *)*sp; 55 } 56 printf("\n"); 57 } 58 59 void show_regs(struct pt_regs *regs) 60 { 61 int i; 62 63 printf("NIP: %08lX XER: %08lX LR: %08lX REGS: %p TRAP: %04lx DAR: %08lX\n", 64 regs->nip, regs->xer, regs->link, regs, regs->trap, regs->dar); 65 printf("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n", 66 regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0, 67 regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0, 68 regs->msr&MSR_IR ? 1 : 0, 69 regs->msr&MSR_DR ? 1 : 0); 70 71 printf("\n"); 72 for (i = 0; i < 32; i++) { 73 if ((i % 8) == 0) 74 { 75 printf("GPR%02d: ", i); 76 } 77 78 printf("%08lX ", regs->gpr[i]); 79 if ((i % 8) == 7) 80 { 81 printf("\n"); 82 } 83 } 84 } 85 86 87 static void _exception(int signr, struct pt_regs *regs) 88 { 89 show_regs(regs); 90 print_backtrace((unsigned long *)regs->gpr[1]); 91 panic("Exception in kernel pc %lx signal %d",regs->nip,signr); 92 } 93 94 void MachineCheckException(struct pt_regs *regs) 95 { 96 unsigned long fixup; 97 98 /* Probing PCI using config cycles cause this exception 99 * when a device is not present. Catch it and return to 100 * the PCI exception handler. 101 */ 102 if ((fixup = search_exception_table(regs->nip)) != 0) { 103 regs->nip = fixup; 104 return; 105 } 106 107 #if defined(CONFIG_CMD_KGDB) 108 if (debugger_exception_handler && (*debugger_exception_handler)(regs)) 109 return; 110 #endif 111 112 printf("Machine check in kernel mode.\n"); 113 printf("Caused by (from msr): "); 114 printf("regs %p ",regs); 115 switch( regs->msr & 0x000F0000) { 116 case (0x80000000>>12): 117 printf("Machine check signal - probably due to mm fault\n" 118 "with mmu off\n"); 119 break; 120 case (0x80000000>>13): 121 printf("Transfer error ack signal\n"); 122 break; 123 case (0x80000000>>14): 124 printf("Data parity signal\n"); 125 break; 126 case (0x80000000>>15): 127 printf("Address parity signal\n"); 128 break; 129 default: 130 printf("Unknown values in msr\n"); 131 } 132 show_regs(regs); 133 print_backtrace((unsigned long *)regs->gpr[1]); 134 panic("machine check"); 135 } 136 137 void AlignmentException(struct pt_regs *regs) 138 { 139 #if defined(CONFIG_CMD_KGDB) 140 if (debugger_exception_handler && (*debugger_exception_handler)(regs)) 141 return; 142 #endif 143 show_regs(regs); 144 print_backtrace((unsigned long *)regs->gpr[1]); 145 panic("Alignment Exception"); 146 } 147 148 void ProgramCheckException(struct pt_regs *regs) 149 { 150 #if defined(CONFIG_CMD_KGDB) 151 if (debugger_exception_handler && (*debugger_exception_handler)(regs)) 152 return; 153 #endif 154 show_regs(regs); 155 print_backtrace((unsigned long *)regs->gpr[1]); 156 panic("Program Check Exception"); 157 } 158 159 void SoftEmuException(struct pt_regs *regs) 160 { 161 #if defined(CONFIG_CMD_KGDB) 162 if (debugger_exception_handler && (*debugger_exception_handler)(regs)) 163 return; 164 #endif 165 show_regs(regs); 166 print_backtrace((unsigned long *)regs->gpr[1]); 167 panic("Software Emulation Exception"); 168 } 169 170 171 void UnknownException(struct pt_regs *regs) 172 { 173 #if defined(CONFIG_CMD_KGDB) 174 if (debugger_exception_handler && (*debugger_exception_handler)(regs)) 175 return; 176 #endif 177 printf("Bad trap at PC: %lx, SR: %lx, vector=%lx\n", 178 regs->nip, regs->msr, regs->trap); 179 _exception(0, regs); 180 } 181 182 void DebugException(struct pt_regs *regs) 183 { 184 printf("Debugger trap at @ %lx\n", regs->nip ); 185 show_regs(regs); 186 #if defined(CONFIG_CMD_BEDBUG) 187 do_bedbug_breakpoint( regs ); 188 #endif 189 } 190 191 /* Probe an address by reading. If not present, return -1, otherwise 192 * return 0. 193 */ 194 int addr_probe(uint *addr) 195 { 196 #if 0 197 int retval; 198 199 __asm__ __volatile__( \ 200 "1: lwz %0,0(%1)\n" \ 201 " eieio\n" \ 202 " li %0,0\n" \ 203 "2:\n" \ 204 ".section .fixup,\"ax\"\n" \ 205 "3: li %0,-1\n" \ 206 " b 2b\n" \ 207 ".section __ex_table,\"a\"\n" \ 208 " .align 2\n" \ 209 " .long 1b,3b\n" \ 210 ".text" \ 211 : "=r" (retval) : "r"(addr)); 212 213 return (retval); 214 #endif 215 return 0; 216 } 217