Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * ppc-stub.c: KGDB support for the Linux kernel. |
| 3 | * |
| 4 | * adapted from arch/sparc/kernel/sparc-stub.c for the PowerPC |
| 5 | * some stuff borrowed from Paul Mackerras' xmon |
| 6 | * Copyright (C) 1998 Michael AK Tesch (tesch@cs.wisc.edu) |
| 7 | * |
| 8 | * Modifications to run under Linux |
| 9 | * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) |
| 10 | * |
| 11 | * This file originally came from the gdb sources, and the |
| 12 | * copyright notices have been retained below. |
| 13 | */ |
| 14 | |
| 15 | /**************************************************************************** |
| 16 | |
| 17 | THIS SOFTWARE IS NOT COPYRIGHTED |
| 18 | |
| 19 | HP offers the following for use in the public domain. HP makes no |
| 20 | warranty with regard to the software or its performance and the |
| 21 | user accepts the software "AS IS" with all faults. |
| 22 | |
| 23 | HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD |
| 24 | TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
| 25 | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 26 | |
| 27 | ****************************************************************************/ |
| 28 | |
| 29 | /**************************************************************************** |
| 30 | * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ |
| 31 | * |
| 32 | * Module name: remcom.c $ |
| 33 | * Revision: 1.34 $ |
| 34 | * Date: 91/03/09 12:29:49 $ |
| 35 | * Contributor: Lake Stevens Instrument Division$ |
| 36 | * |
| 37 | * Description: low level support for gdb debugger. $ |
| 38 | * |
| 39 | * Considerations: only works on target hardware $ |
| 40 | * |
| 41 | * Written by: Glenn Engel $ |
| 42 | * ModuleState: Experimental $ |
| 43 | * |
| 44 | * NOTES: See Below $ |
| 45 | * |
| 46 | * Modified for SPARC by Stu Grossman, Cygnus Support. |
| 47 | * |
| 48 | * This code has been extensively tested on the Fujitsu SPARClite demo board. |
| 49 | * |
| 50 | * To enable debugger support, two things need to happen. One, a |
| 51 | * call to set_debug_traps() is necessary in order to allow any breakpoints |
| 52 | * or error conditions to be properly intercepted and reported to gdb. |
| 53 | * Two, a breakpoint needs to be generated to begin communication. This |
| 54 | * is most easily accomplished by a call to breakpoint(). Breakpoint() |
| 55 | * simulates a breakpoint by executing a trap #1. |
| 56 | * |
| 57 | ************* |
| 58 | * |
| 59 | * The following gdb commands are supported: |
| 60 | * |
| 61 | * command function Return value |
| 62 | * |
| 63 | * g return the value of the CPU registers hex data or ENN |
| 64 | * G set the value of the CPU registers OK or ENN |
| 65 | * qOffsets Get section offsets. Reply is Text=xxx;Data=yyy;Bss=zzz |
| 66 | * |
| 67 | * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN |
| 68 | * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN |
| 69 | * |
| 70 | * c Resume at current address SNN ( signal NN) |
| 71 | * cAA..AA Continue at address AA..AA SNN |
| 72 | * |
| 73 | * s Step one instruction SNN |
| 74 | * sAA..AA Step one instruction from AA..AA SNN |
| 75 | * |
| 76 | * k kill |
| 77 | * |
| 78 | * ? What was the last sigval ? SNN (signal NN) |
| 79 | * |
| 80 | * bBB..BB Set baud rate to BB..BB OK or BNN, then sets |
| 81 | * baud rate |
| 82 | * |
| 83 | * All commands and responses are sent with a packet which includes a |
| 84 | * checksum. A packet consists of |
| 85 | * |
| 86 | * $<packet info>#<checksum>. |
| 87 | * |
| 88 | * where |
| 89 | * <packet info> :: <characters representing the command or response> |
| 90 | * <checksum> :: <two hex digits computed as modulo 256 sum of <packetinfo>> |
| 91 | * |
| 92 | * When a packet is received, it is first acknowledged with either '+' or '-'. |
| 93 | * '+' indicates a successful transfer. '-' indicates a failed transfer. |
| 94 | * |
| 95 | * Example: |
| 96 | * |
| 97 | * Host: Reply: |
| 98 | * $m0,10#2a +$00010203040506070809101112131415#42 |
| 99 | * |
| 100 | ****************************************************************************/ |
| 101 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | #include <linux/kernel.h> |
| 103 | #include <linux/string.h> |
| 104 | #include <linux/mm.h> |
| 105 | #include <linux/smp.h> |
| 106 | #include <linux/smp_lock.h> |
| 107 | #include <linux/init.h> |
| 108 | #include <linux/sysrq.h> |
| 109 | |
| 110 | #include <asm/cacheflush.h> |
| 111 | #include <asm/system.h> |
| 112 | #include <asm/signal.h> |
| 113 | #include <asm/kgdb.h> |
| 114 | #include <asm/pgtable.h> |
| 115 | #include <asm/ptrace.h> |
| 116 | |
| 117 | void breakinst(void); |
| 118 | |
| 119 | /* |
| 120 | * BUFMAX defines the maximum number of characters in inbound/outbound buffers |
| 121 | * at least NUMREGBYTES*2 are needed for register packets |
| 122 | */ |
| 123 | #define BUFMAX 2048 |
| 124 | static char remcomInBuffer[BUFMAX]; |
| 125 | static char remcomOutBuffer[BUFMAX]; |
| 126 | |
| 127 | static int initialized; |
| 128 | static int kgdb_active; |
| 129 | static int kgdb_started; |
| 130 | static u_int fault_jmp_buf[100]; |
| 131 | static int kdebug; |
| 132 | |
| 133 | |
| 134 | static const char hexchars[]="0123456789abcdef"; |
| 135 | |
| 136 | /* Place where we save old trap entries for restoration - sparc*/ |
| 137 | /* struct tt_entry kgdb_savettable[256]; */ |
| 138 | /* typedef void (*trapfunc_t)(void); */ |
| 139 | |
| 140 | static void kgdb_fault_handler(struct pt_regs *regs); |
| 141 | static int handle_exception (struct pt_regs *regs); |
| 142 | |
| 143 | #if 0 |
| 144 | /* Install an exception handler for kgdb */ |
| 145 | static void exceptionHandler(int tnum, unsigned int *tfunc) |
| 146 | { |
| 147 | /* We are dorking with a live trap table, all irqs off */ |
| 148 | } |
| 149 | #endif |
| 150 | |
| 151 | int |
| 152 | kgdb_setjmp(long *buf) |
| 153 | { |
| 154 | asm ("mflr 0; stw 0,0(%0);" |
| 155 | "stw 1,4(%0); stw 2,8(%0);" |
| 156 | "mfcr 0; stw 0,12(%0);" |
| 157 | "stmw 13,16(%0)" |
| 158 | : : "r" (buf)); |
| 159 | /* XXX should save fp regs as well */ |
| 160 | return 0; |
| 161 | } |
| 162 | void |
| 163 | kgdb_longjmp(long *buf, int val) |
| 164 | { |
| 165 | if (val == 0) |
| 166 | val = 1; |
| 167 | asm ("lmw 13,16(%0);" |
| 168 | "lwz 0,12(%0); mtcrf 0x38,0;" |
| 169 | "lwz 0,0(%0); lwz 1,4(%0); lwz 2,8(%0);" |
| 170 | "mtlr 0; mr 3,%1" |
| 171 | : : "r" (buf), "r" (val)); |
| 172 | } |
| 173 | /* Convert ch from a hex digit to an int */ |
| 174 | static int |
| 175 | hex(unsigned char ch) |
| 176 | { |
| 177 | if (ch >= 'a' && ch <= 'f') |
| 178 | return ch-'a'+10; |
| 179 | if (ch >= '0' && ch <= '9') |
| 180 | return ch-'0'; |
| 181 | if (ch >= 'A' && ch <= 'F') |
| 182 | return ch-'A'+10; |
| 183 | return -1; |
| 184 | } |
| 185 | |
| 186 | /* Convert the memory pointed to by mem into hex, placing result in buf. |
| 187 | * Return a pointer to the last char put in buf (null), in case of mem fault, |
| 188 | * return 0. |
| 189 | */ |
| 190 | static unsigned char * |
| 191 | mem2hex(const char *mem, char *buf, int count) |
| 192 | { |
| 193 | unsigned char ch; |
| 194 | unsigned short tmp_s; |
| 195 | unsigned long tmp_l; |
| 196 | |
| 197 | if (kgdb_setjmp((long*)fault_jmp_buf) == 0) { |
| 198 | debugger_fault_handler = kgdb_fault_handler; |
| 199 | |
| 200 | /* Accessing 16 bit and 32 bit objects in a single |
| 201 | ** load instruction is required to avoid bad side |
| 202 | ** effects for some IO registers. |
| 203 | */ |
| 204 | |
| 205 | if ((count == 2) && (((long)mem & 1) == 0)) { |
| 206 | tmp_s = *(unsigned short *)mem; |
| 207 | mem += 2; |
| 208 | *buf++ = hexchars[(tmp_s >> 12) & 0xf]; |
| 209 | *buf++ = hexchars[(tmp_s >> 8) & 0xf]; |
| 210 | *buf++ = hexchars[(tmp_s >> 4) & 0xf]; |
| 211 | *buf++ = hexchars[tmp_s & 0xf]; |
| 212 | |
| 213 | } else if ((count == 4) && (((long)mem & 3) == 0)) { |
| 214 | tmp_l = *(unsigned int *)mem; |
| 215 | mem += 4; |
| 216 | *buf++ = hexchars[(tmp_l >> 28) & 0xf]; |
| 217 | *buf++ = hexchars[(tmp_l >> 24) & 0xf]; |
| 218 | *buf++ = hexchars[(tmp_l >> 20) & 0xf]; |
| 219 | *buf++ = hexchars[(tmp_l >> 16) & 0xf]; |
| 220 | *buf++ = hexchars[(tmp_l >> 12) & 0xf]; |
| 221 | *buf++ = hexchars[(tmp_l >> 8) & 0xf]; |
| 222 | *buf++ = hexchars[(tmp_l >> 4) & 0xf]; |
| 223 | *buf++ = hexchars[tmp_l & 0xf]; |
| 224 | |
| 225 | } else { |
| 226 | while (count-- > 0) { |
| 227 | ch = *mem++; |
| 228 | *buf++ = hexchars[ch >> 4]; |
| 229 | *buf++ = hexchars[ch & 0xf]; |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | } else { |
| 234 | /* error condition */ |
| 235 | } |
| 236 | debugger_fault_handler = NULL; |
| 237 | *buf = 0; |
| 238 | return buf; |
| 239 | } |
| 240 | |
| 241 | /* convert the hex array pointed to by buf into binary to be placed in mem |
| 242 | * return a pointer to the character AFTER the last byte written. |
| 243 | */ |
| 244 | static char * |
| 245 | hex2mem(char *buf, char *mem, int count) |
| 246 | { |
| 247 | unsigned char ch; |
| 248 | int i; |
| 249 | char *orig_mem; |
| 250 | unsigned short tmp_s; |
| 251 | unsigned long tmp_l; |
| 252 | |
| 253 | orig_mem = mem; |
| 254 | |
| 255 | if (kgdb_setjmp((long*)fault_jmp_buf) == 0) { |
| 256 | debugger_fault_handler = kgdb_fault_handler; |
| 257 | |
| 258 | /* Accessing 16 bit and 32 bit objects in a single |
| 259 | ** store instruction is required to avoid bad side |
| 260 | ** effects for some IO registers. |
| 261 | */ |
| 262 | |
| 263 | if ((count == 2) && (((long)mem & 1) == 0)) { |
| 264 | tmp_s = hex(*buf++) << 12; |
| 265 | tmp_s |= hex(*buf++) << 8; |
| 266 | tmp_s |= hex(*buf++) << 4; |
| 267 | tmp_s |= hex(*buf++); |
| 268 | |
| 269 | *(unsigned short *)mem = tmp_s; |
| 270 | mem += 2; |
| 271 | |
| 272 | } else if ((count == 4) && (((long)mem & 3) == 0)) { |
| 273 | tmp_l = hex(*buf++) << 28; |
| 274 | tmp_l |= hex(*buf++) << 24; |
| 275 | tmp_l |= hex(*buf++) << 20; |
| 276 | tmp_l |= hex(*buf++) << 16; |
| 277 | tmp_l |= hex(*buf++) << 12; |
| 278 | tmp_l |= hex(*buf++) << 8; |
| 279 | tmp_l |= hex(*buf++) << 4; |
| 280 | tmp_l |= hex(*buf++); |
| 281 | |
| 282 | *(unsigned long *)mem = tmp_l; |
| 283 | mem += 4; |
| 284 | |
| 285 | } else { |
| 286 | for (i=0; i<count; i++) { |
| 287 | ch = hex(*buf++) << 4; |
| 288 | ch |= hex(*buf++); |
| 289 | *mem++ = ch; |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | |
| 294 | /* |
| 295 | ** Flush the data cache, invalidate the instruction cache. |
| 296 | */ |
| 297 | flush_icache_range((int)orig_mem, (int)orig_mem + count - 1); |
| 298 | |
| 299 | } else { |
| 300 | /* error condition */ |
| 301 | } |
| 302 | debugger_fault_handler = NULL; |
| 303 | return mem; |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * While we find nice hex chars, build an int. |
| 308 | * Return number of chars processed. |
| 309 | */ |
| 310 | static int |
| 311 | hexToInt(char **ptr, int *intValue) |
| 312 | { |
| 313 | int numChars = 0; |
| 314 | int hexValue; |
| 315 | |
| 316 | *intValue = 0; |
| 317 | |
| 318 | if (kgdb_setjmp((long*)fault_jmp_buf) == 0) { |
| 319 | debugger_fault_handler = kgdb_fault_handler; |
| 320 | while (**ptr) { |
| 321 | hexValue = hex(**ptr); |
| 322 | if (hexValue < 0) |
| 323 | break; |
| 324 | |
| 325 | *intValue = (*intValue << 4) | hexValue; |
| 326 | numChars ++; |
| 327 | |
| 328 | (*ptr)++; |
| 329 | } |
| 330 | } else { |
| 331 | /* error condition */ |
| 332 | } |
| 333 | debugger_fault_handler = NULL; |
| 334 | |
| 335 | return (numChars); |
| 336 | } |
| 337 | |
| 338 | /* scan for the sequence $<data>#<checksum> */ |
| 339 | static void |
| 340 | getpacket(char *buffer) |
| 341 | { |
| 342 | unsigned char checksum; |
| 343 | unsigned char xmitcsum; |
| 344 | int i; |
| 345 | int count; |
| 346 | unsigned char ch; |
| 347 | |
| 348 | do { |
| 349 | /* wait around for the start character, ignore all other |
| 350 | * characters */ |
| 351 | while ((ch = (getDebugChar() & 0x7f)) != '$') ; |
| 352 | |
| 353 | checksum = 0; |
| 354 | xmitcsum = -1; |
| 355 | |
| 356 | count = 0; |
| 357 | |
| 358 | /* now, read until a # or end of buffer is found */ |
| 359 | while (count < BUFMAX) { |
| 360 | ch = getDebugChar() & 0x7f; |
| 361 | if (ch == '#') |
| 362 | break; |
| 363 | checksum = checksum + ch; |
| 364 | buffer[count] = ch; |
| 365 | count = count + 1; |
| 366 | } |
| 367 | |
| 368 | if (count >= BUFMAX) |
| 369 | continue; |
| 370 | |
| 371 | buffer[count] = 0; |
| 372 | |
| 373 | if (ch == '#') { |
| 374 | xmitcsum = hex(getDebugChar() & 0x7f) << 4; |
| 375 | xmitcsum |= hex(getDebugChar() & 0x7f); |
| 376 | if (checksum != xmitcsum) |
| 377 | putDebugChar('-'); /* failed checksum */ |
| 378 | else { |
| 379 | putDebugChar('+'); /* successful transfer */ |
| 380 | /* if a sequence char is present, reply the ID */ |
| 381 | if (buffer[2] == ':') { |
| 382 | putDebugChar(buffer[0]); |
| 383 | putDebugChar(buffer[1]); |
| 384 | /* remove sequence chars from buffer */ |
| 385 | count = strlen(buffer); |
| 386 | for (i=3; i <= count; i++) |
| 387 | buffer[i-3] = buffer[i]; |
| 388 | } |
| 389 | } |
| 390 | } |
| 391 | } while (checksum != xmitcsum); |
| 392 | } |
| 393 | |
| 394 | /* send the packet in buffer. */ |
| 395 | static void putpacket(unsigned char *buffer) |
| 396 | { |
| 397 | unsigned char checksum; |
| 398 | int count; |
| 399 | unsigned char ch, recv; |
| 400 | |
| 401 | /* $<packet info>#<checksum>. */ |
| 402 | do { |
| 403 | putDebugChar('$'); |
| 404 | checksum = 0; |
| 405 | count = 0; |
| 406 | |
| 407 | while ((ch = buffer[count])) { |
| 408 | putDebugChar(ch); |
| 409 | checksum += ch; |
| 410 | count += 1; |
| 411 | } |
| 412 | |
| 413 | putDebugChar('#'); |
| 414 | putDebugChar(hexchars[checksum >> 4]); |
| 415 | putDebugChar(hexchars[checksum & 0xf]); |
| 416 | recv = getDebugChar(); |
| 417 | } while ((recv & 0x7f) != '+'); |
| 418 | } |
| 419 | |
| 420 | static void kgdb_flush_cache_all(void) |
| 421 | { |
| 422 | flush_instruction_cache(); |
| 423 | } |
| 424 | |
| 425 | /* Set up exception handlers for tracing and breakpoints |
| 426 | * [could be called kgdb_init()] |
| 427 | */ |
| 428 | void set_debug_traps(void) |
| 429 | { |
| 430 | #if 0 |
| 431 | unsigned char c; |
| 432 | |
| 433 | save_and_cli(flags); |
| 434 | |
| 435 | /* In case GDB is started before us, ack any packets (presumably |
| 436 | * "$?#xx") sitting there. |
| 437 | * |
| 438 | * I've found this code causes more problems than it solves, |
| 439 | * so that's why it's commented out. GDB seems to work fine |
| 440 | * now starting either before or after the kernel -bwb |
| 441 | */ |
| 442 | |
| 443 | while((c = getDebugChar()) != '$'); |
| 444 | while((c = getDebugChar()) != '#'); |
| 445 | c = getDebugChar(); /* eat first csum byte */ |
| 446 | c = getDebugChar(); /* eat second csum byte */ |
| 447 | putDebugChar('+'); /* ack it */ |
| 448 | #endif |
| 449 | debugger = kgdb; |
| 450 | debugger_bpt = kgdb_bpt; |
| 451 | debugger_sstep = kgdb_sstep; |
| 452 | debugger_iabr_match = kgdb_iabr_match; |
| 453 | debugger_dabr_match = kgdb_dabr_match; |
| 454 | |
| 455 | initialized = 1; |
| 456 | } |
| 457 | |
| 458 | static void kgdb_fault_handler(struct pt_regs *regs) |
| 459 | { |
| 460 | kgdb_longjmp((long*)fault_jmp_buf, 1); |
| 461 | } |
| 462 | |
| 463 | int kgdb_bpt(struct pt_regs *regs) |
| 464 | { |
| 465 | return handle_exception(regs); |
| 466 | } |
| 467 | |
| 468 | int kgdb_sstep(struct pt_regs *regs) |
| 469 | { |
| 470 | return handle_exception(regs); |
| 471 | } |
| 472 | |
| 473 | void kgdb(struct pt_regs *regs) |
| 474 | { |
| 475 | handle_exception(regs); |
| 476 | } |
| 477 | |
| 478 | int kgdb_iabr_match(struct pt_regs *regs) |
| 479 | { |
| 480 | printk(KERN_ERR "kgdb doesn't support iabr, what?!?\n"); |
| 481 | return handle_exception(regs); |
| 482 | } |
| 483 | |
| 484 | int kgdb_dabr_match(struct pt_regs *regs) |
| 485 | { |
| 486 | printk(KERN_ERR "kgdb doesn't support dabr, what?!?\n"); |
| 487 | return handle_exception(regs); |
| 488 | } |
| 489 | |
| 490 | /* Convert the hardware trap type code to a unix signal number. */ |
| 491 | /* |
| 492 | * This table contains the mapping between PowerPC hardware trap types, and |
| 493 | * signals, which are primarily what GDB understands. |
| 494 | */ |
| 495 | static struct hard_trap_info |
| 496 | { |
| 497 | unsigned int tt; /* Trap type code for powerpc */ |
| 498 | unsigned char signo; /* Signal that we map this trap into */ |
| 499 | } hard_trap_info[] = { |
| 500 | #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) |
| 501 | { 0x100, SIGINT }, /* critical input interrupt */ |
| 502 | { 0x200, SIGSEGV }, /* machine check */ |
| 503 | { 0x300, SIGSEGV }, /* data storage */ |
| 504 | { 0x400, SIGBUS }, /* instruction storage */ |
| 505 | { 0x500, SIGINT }, /* interrupt */ |
| 506 | { 0x600, SIGBUS }, /* alignment */ |
| 507 | { 0x700, SIGILL }, /* program */ |
| 508 | { 0x800, SIGILL }, /* reserved */ |
| 509 | { 0x900, SIGILL }, /* reserved */ |
| 510 | { 0xa00, SIGILL }, /* reserved */ |
| 511 | { 0xb00, SIGILL }, /* reserved */ |
| 512 | { 0xc00, SIGCHLD }, /* syscall */ |
| 513 | { 0xd00, SIGILL }, /* reserved */ |
| 514 | { 0xe00, SIGILL }, /* reserved */ |
| 515 | { 0xf00, SIGILL }, /* reserved */ |
| 516 | /* |
| 517 | ** 0x1000 PIT |
| 518 | ** 0x1010 FIT |
| 519 | ** 0x1020 watchdog |
| 520 | ** 0x1100 data TLB miss |
| 521 | ** 0x1200 instruction TLB miss |
| 522 | */ |
| 523 | { 0x2002, SIGTRAP}, /* debug */ |
| 524 | #else |
| 525 | { 0x200, SIGSEGV }, /* machine check */ |
| 526 | { 0x300, SIGSEGV }, /* address error (store) */ |
| 527 | { 0x400, SIGBUS }, /* instruction bus error */ |
| 528 | { 0x500, SIGINT }, /* interrupt */ |
| 529 | { 0x600, SIGBUS }, /* alingment */ |
| 530 | { 0x700, SIGTRAP }, /* breakpoint trap */ |
| 531 | { 0x800, SIGFPE }, /* fpu unavail */ |
| 532 | { 0x900, SIGALRM }, /* decrementer */ |
| 533 | { 0xa00, SIGILL }, /* reserved */ |
| 534 | { 0xb00, SIGILL }, /* reserved */ |
| 535 | { 0xc00, SIGCHLD }, /* syscall */ |
| 536 | { 0xd00, SIGTRAP }, /* single-step/watch */ |
| 537 | { 0xe00, SIGFPE }, /* fp assist */ |
| 538 | #endif |
| 539 | { 0, 0} /* Must be last */ |
| 540 | |
| 541 | }; |
| 542 | |
| 543 | static int computeSignal(unsigned int tt) |
| 544 | { |
| 545 | struct hard_trap_info *ht; |
| 546 | |
| 547 | for (ht = hard_trap_info; ht->tt && ht->signo; ht++) |
| 548 | if (ht->tt == tt) |
| 549 | return ht->signo; |
| 550 | |
| 551 | return SIGHUP; /* default for things we don't know about */ |
| 552 | } |
| 553 | |
| 554 | #define PC_REGNUM 64 |
| 555 | #define SP_REGNUM 1 |
| 556 | |
| 557 | /* |
| 558 | * This function does all command processing for interfacing to gdb. |
| 559 | */ |
| 560 | static int |
| 561 | handle_exception (struct pt_regs *regs) |
| 562 | { |
| 563 | int sigval; |
| 564 | int addr; |
| 565 | int length; |
| 566 | char *ptr; |
| 567 | unsigned int msr; |
| 568 | |
| 569 | /* We don't handle user-mode breakpoints. */ |
| 570 | if (user_mode(regs)) |
| 571 | return 0; |
| 572 | |
| 573 | if (debugger_fault_handler) { |
| 574 | debugger_fault_handler(regs); |
| 575 | panic("kgdb longjump failed!\n"); |
| 576 | } |
| 577 | if (kgdb_active) { |
| 578 | printk(KERN_ERR "interrupt while in kgdb, returning\n"); |
| 579 | return 0; |
| 580 | } |
| 581 | |
| 582 | kgdb_active = 1; |
| 583 | kgdb_started = 1; |
| 584 | |
| 585 | #ifdef KGDB_DEBUG |
| 586 | printk("kgdb: entering handle_exception; trap [0x%x]\n", |
| 587 | (unsigned int)regs->trap); |
| 588 | #endif |
| 589 | |
| 590 | kgdb_interruptible(0); |
| 591 | lock_kernel(); |
| 592 | msr = mfmsr(); |
| 593 | mtmsr(msr & ~MSR_EE); /* disable interrupts */ |
| 594 | |
| 595 | if (regs->nip == (unsigned long)breakinst) { |
| 596 | /* Skip over breakpoint trap insn */ |
| 597 | regs->nip += 4; |
| 598 | } |
| 599 | |
| 600 | /* reply to host that an exception has occurred */ |
| 601 | sigval = computeSignal(regs->trap); |
| 602 | ptr = remcomOutBuffer; |
| 603 | |
| 604 | *ptr++ = 'T'; |
| 605 | *ptr++ = hexchars[sigval >> 4]; |
| 606 | *ptr++ = hexchars[sigval & 0xf]; |
| 607 | *ptr++ = hexchars[PC_REGNUM >> 4]; |
| 608 | *ptr++ = hexchars[PC_REGNUM & 0xf]; |
| 609 | *ptr++ = ':'; |
| 610 | ptr = mem2hex((char *)®s->nip, ptr, 4); |
| 611 | *ptr++ = ';'; |
| 612 | *ptr++ = hexchars[SP_REGNUM >> 4]; |
| 613 | *ptr++ = hexchars[SP_REGNUM & 0xf]; |
| 614 | *ptr++ = ':'; |
| 615 | ptr = mem2hex(((char *)regs) + SP_REGNUM*4, ptr, 4); |
| 616 | *ptr++ = ';'; |
| 617 | *ptr++ = 0; |
| 618 | |
| 619 | putpacket(remcomOutBuffer); |
| 620 | if (kdebug) |
| 621 | printk("remcomOutBuffer: %s\n", remcomOutBuffer); |
| 622 | |
| 623 | /* XXX We may want to add some features dealing with poking the |
| 624 | * XXX page tables, ... (look at sparc-stub.c for more info) |
| 625 | * XXX also required hacking to the gdb sources directly... |
| 626 | */ |
| 627 | |
| 628 | while (1) { |
| 629 | remcomOutBuffer[0] = 0; |
| 630 | |
| 631 | getpacket(remcomInBuffer); |
| 632 | switch (remcomInBuffer[0]) { |
| 633 | case '?': /* report most recent signal */ |
| 634 | remcomOutBuffer[0] = 'S'; |
| 635 | remcomOutBuffer[1] = hexchars[sigval >> 4]; |
| 636 | remcomOutBuffer[2] = hexchars[sigval & 0xf]; |
| 637 | remcomOutBuffer[3] = 0; |
| 638 | break; |
| 639 | #if 0 |
| 640 | case 'q': /* this screws up gdb for some reason...*/ |
| 641 | { |
| 642 | extern long _start, sdata, __bss_start; |
| 643 | |
| 644 | ptr = &remcomInBuffer[1]; |
| 645 | if (strncmp(ptr, "Offsets", 7) != 0) |
| 646 | break; |
| 647 | |
| 648 | ptr = remcomOutBuffer; |
| 649 | sprintf(ptr, "Text=%8.8x;Data=%8.8x;Bss=%8.8x", |
| 650 | &_start, &sdata, &__bss_start); |
| 651 | break; |
| 652 | } |
| 653 | #endif |
| 654 | case 'd': |
| 655 | /* toggle debug flag */ |
| 656 | kdebug ^= 1; |
| 657 | break; |
| 658 | |
| 659 | case 'g': /* return the value of the CPU registers. |
| 660 | * some of them are non-PowerPC names :( |
| 661 | * they are stored in gdb like: |
| 662 | * struct { |
| 663 | * u32 gpr[32]; |
| 664 | * f64 fpr[32]; |
| 665 | * u32 pc, ps, cnd, lr; (ps=msr) |
| 666 | * u32 cnt, xer, mq; |
| 667 | * } |
| 668 | */ |
| 669 | { |
| 670 | int i; |
| 671 | ptr = remcomOutBuffer; |
| 672 | /* General Purpose Regs */ |
| 673 | ptr = mem2hex((char *)regs, ptr, 32 * 4); |
| 674 | /* Floating Point Regs - FIXME */ |
| 675 | /*ptr = mem2hex((char *), ptr, 32 * 8);*/ |
| 676 | for(i=0; i<(32*8*2); i++) { /* 2chars/byte */ |
| 677 | ptr[i] = '0'; |
| 678 | } |
| 679 | ptr += 32*8*2; |
| 680 | /* pc, msr, cr, lr, ctr, xer, (mq is unused) */ |
| 681 | ptr = mem2hex((char *)®s->nip, ptr, 4); |
| 682 | ptr = mem2hex((char *)®s->msr, ptr, 4); |
| 683 | ptr = mem2hex((char *)®s->ccr, ptr, 4); |
| 684 | ptr = mem2hex((char *)®s->link, ptr, 4); |
| 685 | ptr = mem2hex((char *)®s->ctr, ptr, 4); |
| 686 | ptr = mem2hex((char *)®s->xer, ptr, 4); |
| 687 | } |
| 688 | break; |
| 689 | |
| 690 | case 'G': /* set the value of the CPU registers */ |
| 691 | { |
| 692 | ptr = &remcomInBuffer[1]; |
| 693 | |
| 694 | /* |
| 695 | * If the stack pointer has moved, you should pray. |
| 696 | * (cause only god can help you). |
| 697 | */ |
| 698 | |
| 699 | /* General Purpose Regs */ |
| 700 | hex2mem(ptr, (char *)regs, 32 * 4); |
| 701 | |
| 702 | /* Floating Point Regs - FIXME?? */ |
| 703 | /*ptr = hex2mem(ptr, ??, 32 * 8);*/ |
| 704 | ptr += 32*8*2; |
| 705 | |
| 706 | /* pc, msr, cr, lr, ctr, xer, (mq is unused) */ |
| 707 | ptr = hex2mem(ptr, (char *)®s->nip, 4); |
| 708 | ptr = hex2mem(ptr, (char *)®s->msr, 4); |
| 709 | ptr = hex2mem(ptr, (char *)®s->ccr, 4); |
| 710 | ptr = hex2mem(ptr, (char *)®s->link, 4); |
| 711 | ptr = hex2mem(ptr, (char *)®s->ctr, 4); |
| 712 | ptr = hex2mem(ptr, (char *)®s->xer, 4); |
| 713 | |
| 714 | strcpy(remcomOutBuffer,"OK"); |
| 715 | } |
| 716 | break; |
| 717 | case 'H': |
| 718 | /* don't do anything, yet, just acknowledge */ |
| 719 | hexToInt(&ptr, &addr); |
| 720 | strcpy(remcomOutBuffer,"OK"); |
| 721 | break; |
| 722 | |
| 723 | case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ |
| 724 | /* Try to read %x,%x. */ |
| 725 | |
| 726 | ptr = &remcomInBuffer[1]; |
| 727 | |
| 728 | if (hexToInt(&ptr, &addr) && *ptr++ == ',' |
| 729 | && hexToInt(&ptr, &length)) { |
| 730 | if (mem2hex((char *)addr, remcomOutBuffer, |
| 731 | length)) |
| 732 | break; |
| 733 | strcpy(remcomOutBuffer, "E03"); |
| 734 | } else |
| 735 | strcpy(remcomOutBuffer, "E01"); |
| 736 | break; |
| 737 | |
| 738 | case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ |
| 739 | /* Try to read '%x,%x:'. */ |
| 740 | |
| 741 | ptr = &remcomInBuffer[1]; |
| 742 | |
| 743 | if (hexToInt(&ptr, &addr) && *ptr++ == ',' |
| 744 | && hexToInt(&ptr, &length) |
| 745 | && *ptr++ == ':') { |
| 746 | if (hex2mem(ptr, (char *)addr, length)) |
| 747 | strcpy(remcomOutBuffer, "OK"); |
| 748 | else |
| 749 | strcpy(remcomOutBuffer, "E03"); |
| 750 | flush_icache_range(addr, addr+length); |
| 751 | } else |
| 752 | strcpy(remcomOutBuffer, "E02"); |
| 753 | break; |
| 754 | |
| 755 | |
| 756 | case 'k': /* kill the program, actually just continue */ |
| 757 | case 'c': /* cAA..AA Continue; address AA..AA optional */ |
| 758 | /* try to read optional parameter, pc unchanged if no parm */ |
| 759 | |
| 760 | ptr = &remcomInBuffer[1]; |
| 761 | if (hexToInt(&ptr, &addr)) |
| 762 | regs->nip = addr; |
| 763 | |
| 764 | /* Need to flush the instruction cache here, as we may have deposited a |
| 765 | * breakpoint, and the icache probably has no way of knowing that a data ref to |
| 766 | * some location may have changed something that is in the instruction cache. |
| 767 | */ |
| 768 | kgdb_flush_cache_all(); |
| 769 | mtmsr(msr); |
| 770 | |
| 771 | kgdb_interruptible(1); |
| 772 | unlock_kernel(); |
| 773 | kgdb_active = 0; |
| 774 | if (kdebug) { |
| 775 | printk("remcomInBuffer: %s\n", remcomInBuffer); |
| 776 | printk("remcomOutBuffer: %s\n", remcomOutBuffer); |
| 777 | } |
| 778 | return 1; |
| 779 | |
| 780 | case 's': |
| 781 | kgdb_flush_cache_all(); |
| 782 | #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) |
| 783 | mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC); |
| 784 | regs->msr |= MSR_DE; |
| 785 | #else |
| 786 | regs->msr |= MSR_SE; |
| 787 | #endif |
| 788 | unlock_kernel(); |
| 789 | kgdb_active = 0; |
| 790 | if (kdebug) { |
| 791 | printk("remcomInBuffer: %s\n", remcomInBuffer); |
| 792 | printk("remcomOutBuffer: %s\n", remcomOutBuffer); |
| 793 | } |
| 794 | return 1; |
| 795 | |
| 796 | case 'r': /* Reset (if user process..exit ???)*/ |
| 797 | panic("kgdb reset."); |
| 798 | break; |
| 799 | } /* switch */ |
| 800 | if (remcomOutBuffer[0] && kdebug) { |
| 801 | printk("remcomInBuffer: %s\n", remcomInBuffer); |
| 802 | printk("remcomOutBuffer: %s\n", remcomOutBuffer); |
| 803 | } |
| 804 | /* reply to the request */ |
| 805 | putpacket(remcomOutBuffer); |
| 806 | } /* while(1) */ |
| 807 | } |
| 808 | |
| 809 | /* This function will generate a breakpoint exception. It is used at the |
| 810 | beginning of a program to sync up with a debugger and can be used |
| 811 | otherwise as a quick means to stop program execution and "break" into |
| 812 | the debugger. */ |
| 813 | |
| 814 | void |
| 815 | breakpoint(void) |
| 816 | { |
| 817 | if (!initialized) { |
| 818 | printk("breakpoint() called b4 kgdb init\n"); |
| 819 | return; |
| 820 | } |
| 821 | |
| 822 | asm(" .globl breakinst \n\ |
| 823 | breakinst: .long 0x7d821008"); |
| 824 | } |
| 825 | |
| 826 | #ifdef CONFIG_KGDB_CONSOLE |
| 827 | /* Output string in GDB O-packet format if GDB has connected. If nothing |
| 828 | output, returns 0 (caller must then handle output). */ |
| 829 | int |
| 830 | kgdb_output_string (const char* s, unsigned int count) |
| 831 | { |
| 832 | char buffer[512]; |
| 833 | |
| 834 | if (!kgdb_started) |
| 835 | return 0; |
| 836 | |
| 837 | count = (count <= (sizeof(buffer) / 2 - 2)) |
| 838 | ? count : (sizeof(buffer) / 2 - 2); |
| 839 | |
| 840 | buffer[0] = 'O'; |
| 841 | mem2hex (s, &buffer[1], count); |
| 842 | putpacket(buffer); |
| 843 | |
| 844 | return 1; |
| 845 | } |
| 846 | #endif |
| 847 | |
| 848 | static void sysrq_handle_gdb(int key, struct pt_regs *pt_regs, |
| 849 | struct tty_struct *tty) |
| 850 | { |
| 851 | printk("Entering GDB stub\n"); |
| 852 | breakpoint(); |
| 853 | } |
| 854 | static struct sysrq_key_op sysrq_gdb_op = { |
| 855 | .handler = sysrq_handle_gdb, |
| 856 | .help_msg = "Gdb", |
| 857 | .action_msg = "GDB", |
| 858 | }; |
| 859 | |
| 860 | static int gdb_register_sysrq(void) |
| 861 | { |
| 862 | printk("Registering GDB sysrq handler\n"); |
| 863 | register_sysrq_key('g', &sysrq_gdb_op); |
| 864 | return 0; |
| 865 | } |
| 866 | module_init(gdb_register_sysrq); |