1 /* 2 * PowerPC backend to the KGDB stub. 3 * 4 * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu) 5 * Copyright (C) 2003 Timesys Corporation. 6 * Copyright (C) 2004-2006 MontaVista Software, Inc. 7 * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com) 8 * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and 9 * Sergei Shtylyov <sshtylyov@ru.mvista.com> 10 * Copyright (C) 2007-2008 Wind River Systems, Inc. 11 * 12 * This file is licensed under the terms of the GNU General Public License 13 * version 2. This program as licensed "as is" without any warranty of any 14 * kind, whether express or implied. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/kgdb.h> 19 #include <linux/smp.h> 20 #include <linux/signal.h> 21 #include <linux/ptrace.h> 22 #include <linux/kdebug.h> 23 #include <asm/current.h> 24 #include <asm/processor.h> 25 #include <asm/machdep.h> 26 #include <asm/debug.h> 27 #include <asm/code-patching.h> 28 #include <linux/slab.h> 29 30 /* 31 * This table contains the mapping between PowerPC hardware trap types, and 32 * signals, which are primarily what GDB understands. GDB and the kernel 33 * don't always agree on values, so we use constants taken from gdb-6.2. 34 */ 35 static struct hard_trap_info 36 { 37 unsigned int tt; /* Trap type code for powerpc */ 38 unsigned char signo; /* Signal that we map this trap into */ 39 } hard_trap_info[] = { 40 { 0x0100, 0x02 /* SIGINT */ }, /* system reset */ 41 { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */ 42 { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */ 43 { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */ 44 { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */ 45 { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */ 46 { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */ 47 { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */ 48 { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */ 49 { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */ 50 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) 51 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */ 52 #if defined(CONFIG_FSL_BOOKE) 53 { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */ 54 { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */ 55 { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */ 56 { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */ 57 { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */ 58 { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */ 59 { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */ 60 { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 61 { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */ 62 #else /* ! CONFIG_FSL_BOOKE */ 63 { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */ 64 { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 65 { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */ 66 { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */ 67 { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */ 68 #endif 69 #else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */ 70 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */ 71 #if defined(CONFIG_PPC_8xx) 72 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */ 73 #else /* ! CONFIG_PPC_8xx */ 74 { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */ 75 { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */ 76 { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */ 77 #if defined(CONFIG_PPC64) 78 { 0x1200, 0x05 /* SIGILL */ }, /* system error */ 79 { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */ 80 { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */ 81 { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */ 82 { 0x1800, 0x04 /* SIGILL */ }, /* thermal */ 83 #else /* ! CONFIG_PPC64 */ 84 { 0x1400, 0x02 /* SIGINT */ }, /* SMI */ 85 { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */ 86 { 0x1700, 0x04 /* SIGILL */ }, /* TAU */ 87 { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */ 88 #endif 89 #endif 90 #endif 91 { 0x0000, 0x00 } /* Must be last */ 92 }; 93 94 static int computeSignal(unsigned int tt) 95 { 96 struct hard_trap_info *ht; 97 98 for (ht = hard_trap_info; ht->tt && ht->signo; ht++) 99 if (ht->tt == tt) 100 return ht->signo; 101 102 return SIGHUP; /* default for things we don't know about */ 103 } 104 105 /** 106 * 107 * kgdb_skipexception - Bail out of KGDB when we've been triggered. 108 * @exception: Exception vector number 109 * @regs: Current &struct pt_regs. 110 * 111 * On some architectures we need to skip a breakpoint exception when 112 * it occurs after a breakpoint has been removed. 113 * 114 */ 115 int kgdb_skipexception(int exception, struct pt_regs *regs) 116 { 117 return kgdb_isremovedbreak(regs->nip); 118 } 119 120 static int kgdb_debugger_ipi(struct pt_regs *regs) 121 { 122 kgdb_nmicallback(raw_smp_processor_id(), regs); 123 return 0; 124 } 125 126 #ifdef CONFIG_SMP 127 void kgdb_roundup_cpus(void) 128 { 129 smp_send_debugger_break(); 130 } 131 #endif 132 133 /* KGDB functions to use existing PowerPC64 hooks. */ 134 static int kgdb_debugger(struct pt_regs *regs) 135 { 136 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), 137 DIE_OOPS, regs); 138 } 139 140 static int kgdb_handle_breakpoint(struct pt_regs *regs) 141 { 142 if (user_mode(regs)) 143 return 0; 144 145 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) 146 return 0; 147 148 if (*(u32 *)regs->nip == BREAK_INSTR) 149 regs->nip += BREAK_INSTR_SIZE; 150 151 return 1; 152 } 153 154 static int kgdb_singlestep(struct pt_regs *regs) 155 { 156 if (user_mode(regs)) 157 return 0; 158 159 kgdb_handle_exception(0, SIGTRAP, 0, regs); 160 161 return 1; 162 } 163 164 static int kgdb_iabr_match(struct pt_regs *regs) 165 { 166 if (user_mode(regs)) 167 return 0; 168 169 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 170 return 0; 171 return 1; 172 } 173 174 static int kgdb_break_match(struct pt_regs *regs) 175 { 176 if (user_mode(regs)) 177 return 0; 178 179 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 180 return 0; 181 return 1; 182 } 183 184 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) 185 186 #define PACK32(ptr, src) do { \ 187 u32 *ptr32; \ 188 ptr32 = (u32 *)ptr; \ 189 *(ptr32++) = (src); \ 190 ptr = (unsigned long *)ptr32; \ 191 } while (0) 192 193 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 194 { 195 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 196 STACK_FRAME_OVERHEAD); 197 unsigned long *ptr = gdb_regs; 198 int reg; 199 200 memset(gdb_regs, 0, NUMREGBYTES); 201 202 /* Regs GPR0-2 */ 203 for (reg = 0; reg < 3; reg++) 204 PACK64(ptr, regs->gpr[reg]); 205 206 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 207 ptr += 11; 208 209 /* Regs GPR14-31 */ 210 for (reg = 14; reg < 32; reg++) 211 PACK64(ptr, regs->gpr[reg]); 212 213 #ifdef CONFIG_FSL_BOOKE 214 #ifdef CONFIG_SPE 215 for (reg = 0; reg < 32; reg++) 216 PACK64(ptr, p->thread.evr[reg]); 217 #else 218 ptr += 32; 219 #endif 220 #else 221 /* fp registers not used by kernel, leave zero */ 222 ptr += 32 * 8 / sizeof(long); 223 #endif 224 225 PACK64(ptr, regs->nip); 226 PACK64(ptr, regs->msr); 227 PACK32(ptr, regs->ccr); 228 PACK64(ptr, regs->link); 229 PACK64(ptr, regs->ctr); 230 PACK32(ptr, regs->xer); 231 232 BUG_ON((unsigned long)ptr > 233 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 234 } 235 236 #define GDB_SIZEOF_REG sizeof(unsigned long) 237 #define GDB_SIZEOF_REG_U32 sizeof(u32) 238 239 #ifdef CONFIG_FSL_BOOKE 240 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long) 241 #else 242 #define GDB_SIZEOF_FLOAT_REG sizeof(u64) 243 #endif 244 245 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 246 { 247 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) }, 248 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) }, 249 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) }, 250 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) }, 251 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) }, 252 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) }, 253 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) }, 254 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) }, 255 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) }, 256 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) }, 257 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) }, 258 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) }, 259 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) }, 260 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) }, 261 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) }, 262 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) }, 263 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) }, 264 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) }, 265 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) }, 266 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) }, 267 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) }, 268 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) }, 269 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) }, 270 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) }, 271 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) }, 272 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) }, 273 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) }, 274 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) }, 275 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) }, 276 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) }, 277 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) }, 278 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) }, 279 280 { "f0", GDB_SIZEOF_FLOAT_REG, 0 }, 281 { "f1", GDB_SIZEOF_FLOAT_REG, 1 }, 282 { "f2", GDB_SIZEOF_FLOAT_REG, 2 }, 283 { "f3", GDB_SIZEOF_FLOAT_REG, 3 }, 284 { "f4", GDB_SIZEOF_FLOAT_REG, 4 }, 285 { "f5", GDB_SIZEOF_FLOAT_REG, 5 }, 286 { "f6", GDB_SIZEOF_FLOAT_REG, 6 }, 287 { "f7", GDB_SIZEOF_FLOAT_REG, 7 }, 288 { "f8", GDB_SIZEOF_FLOAT_REG, 8 }, 289 { "f9", GDB_SIZEOF_FLOAT_REG, 9 }, 290 { "f10", GDB_SIZEOF_FLOAT_REG, 10 }, 291 { "f11", GDB_SIZEOF_FLOAT_REG, 11 }, 292 { "f12", GDB_SIZEOF_FLOAT_REG, 12 }, 293 { "f13", GDB_SIZEOF_FLOAT_REG, 13 }, 294 { "f14", GDB_SIZEOF_FLOAT_REG, 14 }, 295 { "f15", GDB_SIZEOF_FLOAT_REG, 15 }, 296 { "f16", GDB_SIZEOF_FLOAT_REG, 16 }, 297 { "f17", GDB_SIZEOF_FLOAT_REG, 17 }, 298 { "f18", GDB_SIZEOF_FLOAT_REG, 18 }, 299 { "f19", GDB_SIZEOF_FLOAT_REG, 19 }, 300 { "f20", GDB_SIZEOF_FLOAT_REG, 20 }, 301 { "f21", GDB_SIZEOF_FLOAT_REG, 21 }, 302 { "f22", GDB_SIZEOF_FLOAT_REG, 22 }, 303 { "f23", GDB_SIZEOF_FLOAT_REG, 23 }, 304 { "f24", GDB_SIZEOF_FLOAT_REG, 24 }, 305 { "f25", GDB_SIZEOF_FLOAT_REG, 25 }, 306 { "f26", GDB_SIZEOF_FLOAT_REG, 26 }, 307 { "f27", GDB_SIZEOF_FLOAT_REG, 27 }, 308 { "f28", GDB_SIZEOF_FLOAT_REG, 28 }, 309 { "f29", GDB_SIZEOF_FLOAT_REG, 29 }, 310 { "f30", GDB_SIZEOF_FLOAT_REG, 30 }, 311 { "f31", GDB_SIZEOF_FLOAT_REG, 31 }, 312 313 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) }, 314 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) }, 315 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) }, 316 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) }, 317 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) }, 318 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) }, 319 }; 320 321 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 322 { 323 if (regno >= DBG_MAX_REG_NUM || regno < 0) 324 return NULL; 325 326 if (regno < 32 || regno >= 64) 327 /* First 0 -> 31 gpr registers*/ 328 /* pc, msr, ls... registers 64 -> 69 */ 329 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 330 dbg_reg_def[regno].size); 331 332 if (regno >= 32 && regno < 64) { 333 /* FP registers 32 -> 63 */ 334 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 335 if (current) 336 memcpy(mem, ¤t->thread.evr[regno-32], 337 dbg_reg_def[regno].size); 338 #else 339 /* fp registers not used by kernel, leave zero */ 340 memset(mem, 0, dbg_reg_def[regno].size); 341 #endif 342 } 343 344 return dbg_reg_def[regno].name; 345 } 346 347 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 348 { 349 if (regno >= DBG_MAX_REG_NUM || regno < 0) 350 return -EINVAL; 351 352 if (regno < 32 || regno >= 64) 353 /* First 0 -> 31 gpr registers*/ 354 /* pc, msr, ls... registers 64 -> 69 */ 355 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 356 dbg_reg_def[regno].size); 357 358 if (regno >= 32 && regno < 64) { 359 /* FP registers 32 -> 63 */ 360 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 361 memcpy(¤t->thread.evr[regno-32], mem, 362 dbg_reg_def[regno].size); 363 #else 364 /* fp registers not used by kernel, leave zero */ 365 return 0; 366 #endif 367 } 368 369 return 0; 370 } 371 372 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 373 { 374 regs->nip = pc; 375 } 376 377 /* 378 * This function does PowerPC specific procesing for interfacing to gdb. 379 */ 380 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 381 char *remcom_in_buffer, char *remcom_out_buffer, 382 struct pt_regs *linux_regs) 383 { 384 char *ptr = &remcom_in_buffer[1]; 385 unsigned long addr; 386 387 switch (remcom_in_buffer[0]) { 388 /* 389 * sAA..AA Step one instruction from AA..AA 390 * This will return an error to gdb .. 391 */ 392 case 's': 393 case 'c': 394 /* handle the optional parameter */ 395 if (kgdb_hex2long(&ptr, &addr)) 396 linux_regs->nip = addr; 397 398 atomic_set(&kgdb_cpu_doing_single_step, -1); 399 /* set the trace bit if we're stepping */ 400 if (remcom_in_buffer[0] == 's') { 401 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 402 mtspr(SPRN_DBCR0, 403 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 404 linux_regs->msr |= MSR_DE; 405 #else 406 linux_regs->msr |= MSR_SE; 407 #endif 408 atomic_set(&kgdb_cpu_doing_single_step, 409 raw_smp_processor_id()); 410 } 411 return 0; 412 } 413 414 return -1; 415 } 416 417 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 418 { 419 int err; 420 unsigned int instr; 421 unsigned int *addr = (unsigned int *)bpt->bpt_addr; 422 423 err = probe_kernel_address(addr, instr); 424 if (err) 425 return err; 426 427 err = patch_instruction(addr, BREAK_INSTR); 428 if (err) 429 return -EFAULT; 430 431 *(unsigned int *)bpt->saved_instr = instr; 432 433 return 0; 434 } 435 436 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) 437 { 438 int err; 439 unsigned int instr = *(unsigned int *)bpt->saved_instr; 440 unsigned int *addr = (unsigned int *)bpt->bpt_addr; 441 442 err = patch_instruction(addr, instr); 443 if (err) 444 return -EFAULT; 445 446 return 0; 447 } 448 449 /* 450 * Global data 451 */ 452 const struct kgdb_arch arch_kgdb_ops; 453 454 static int kgdb_not_implemented(struct pt_regs *regs) 455 { 456 return 0; 457 } 458 459 static void *old__debugger_ipi; 460 static void *old__debugger; 461 static void *old__debugger_bpt; 462 static void *old__debugger_sstep; 463 static void *old__debugger_iabr_match; 464 static void *old__debugger_break_match; 465 static void *old__debugger_fault_handler; 466 467 int kgdb_arch_init(void) 468 { 469 old__debugger_ipi = __debugger_ipi; 470 old__debugger = __debugger; 471 old__debugger_bpt = __debugger_bpt; 472 old__debugger_sstep = __debugger_sstep; 473 old__debugger_iabr_match = __debugger_iabr_match; 474 old__debugger_break_match = __debugger_break_match; 475 old__debugger_fault_handler = __debugger_fault_handler; 476 477 __debugger_ipi = kgdb_debugger_ipi; 478 __debugger = kgdb_debugger; 479 __debugger_bpt = kgdb_handle_breakpoint; 480 __debugger_sstep = kgdb_singlestep; 481 __debugger_iabr_match = kgdb_iabr_match; 482 __debugger_break_match = kgdb_break_match; 483 __debugger_fault_handler = kgdb_not_implemented; 484 485 return 0; 486 } 487 488 void kgdb_arch_exit(void) 489 { 490 __debugger_ipi = old__debugger_ipi; 491 __debugger = old__debugger; 492 __debugger_bpt = old__debugger_bpt; 493 __debugger_sstep = old__debugger_sstep; 494 __debugger_iabr_match = old__debugger_iabr_match; 495 __debugger_break_match = old__debugger_break_match; 496 __debugger_fault_handler = old__debugger_fault_handler; 497 } 498