kgdb.c (14910B)
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#include <asm/inst.h> 30 31/* 32 * This table contains the mapping between PowerPC hardware trap types, and 33 * signals, which are primarily what GDB understands. GDB and the kernel 34 * don't always agree on values, so we use constants taken from gdb-6.2. 35 */ 36static struct hard_trap_info 37{ 38 unsigned int tt; /* Trap type code for powerpc */ 39 unsigned char signo; /* Signal that we map this trap into */ 40} hard_trap_info[] = { 41 { 0x0100, 0x02 /* SIGINT */ }, /* system reset */ 42 { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */ 43 { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */ 44 { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */ 45 { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */ 46 { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */ 47 { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */ 48 { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */ 49 { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */ 50 { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */ 51#ifdef CONFIG_BOOKE_OR_40x 52 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */ 53#if defined(CONFIG_FSL_BOOKE) 54 { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */ 55 { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */ 56 { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */ 57 { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */ 58 { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */ 59 { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */ 60 { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */ 61 { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 62 { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */ 63#else /* ! CONFIG_FSL_BOOKE */ 64 { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */ 65 { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 66 { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */ 67 { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */ 68 { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */ 69#endif 70#else /* !CONFIG_BOOKE_OR_40x */ 71 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */ 72#if defined(CONFIG_PPC_8xx) 73 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */ 74#else /* ! CONFIG_PPC_8xx */ 75 { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */ 76 { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */ 77 { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */ 78#if defined(CONFIG_PPC64) 79 { 0x1200, 0x05 /* SIGILL */ }, /* system error */ 80 { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */ 81 { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */ 82 { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */ 83 { 0x1800, 0x04 /* SIGILL */ }, /* thermal */ 84#else /* ! CONFIG_PPC64 */ 85 { 0x1400, 0x02 /* SIGINT */ }, /* SMI */ 86 { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */ 87 { 0x1700, 0x04 /* SIGILL */ }, /* TAU */ 88 { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */ 89#endif 90#endif 91#endif 92 { 0x0000, 0x00 } /* Must be last */ 93}; 94 95static int computeSignal(unsigned int tt) 96{ 97 struct hard_trap_info *ht; 98 99 for (ht = hard_trap_info; ht->tt && ht->signo; ht++) 100 if (ht->tt == tt) 101 return ht->signo; 102 103 return SIGHUP; /* default for things we don't know about */ 104} 105 106/** 107 * 108 * kgdb_skipexception - Bail out of KGDB when we've been triggered. 109 * @exception: Exception vector number 110 * @regs: Current &struct pt_regs. 111 * 112 * On some architectures we need to skip a breakpoint exception when 113 * it occurs after a breakpoint has been removed. 114 * 115 */ 116int kgdb_skipexception(int exception, struct pt_regs *regs) 117{ 118 return kgdb_isremovedbreak(regs->nip); 119} 120 121static int kgdb_debugger_ipi(struct pt_regs *regs) 122{ 123 kgdb_nmicallback(raw_smp_processor_id(), regs); 124 return 0; 125} 126 127#ifdef CONFIG_SMP 128void kgdb_roundup_cpus(void) 129{ 130 smp_send_debugger_break(); 131} 132#endif 133 134/* KGDB functions to use existing PowerPC64 hooks. */ 135static int kgdb_debugger(struct pt_regs *regs) 136{ 137 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), 138 DIE_OOPS, regs); 139} 140 141static int kgdb_handle_breakpoint(struct pt_regs *regs) 142{ 143 if (user_mode(regs)) 144 return 0; 145 146 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) 147 return 0; 148 149 if (*(u32 *)regs->nip == BREAK_INSTR) 150 regs_add_return_ip(regs, BREAK_INSTR_SIZE); 151 152 return 1; 153} 154 155static int kgdb_singlestep(struct pt_regs *regs) 156{ 157 if (user_mode(regs)) 158 return 0; 159 160 kgdb_handle_exception(0, SIGTRAP, 0, regs); 161 162 return 1; 163} 164 165static int kgdb_iabr_match(struct pt_regs *regs) 166{ 167 if (user_mode(regs)) 168 return 0; 169 170 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 171 return 0; 172 return 1; 173} 174 175static int kgdb_break_match(struct pt_regs *regs) 176{ 177 if (user_mode(regs)) 178 return 0; 179 180 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 181 return 0; 182 return 1; 183} 184 185#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) 186 187#define PACK32(ptr, src) do { \ 188 u32 *ptr32; \ 189 ptr32 = (u32 *)ptr; \ 190 *(ptr32++) = (src); \ 191 ptr = (unsigned long *)ptr32; \ 192 } while (0) 193 194void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 195{ 196 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 197 STACK_FRAME_OVERHEAD); 198 unsigned long *ptr = gdb_regs; 199 int reg; 200 201 memset(gdb_regs, 0, NUMREGBYTES); 202 203 /* Regs GPR0-2 */ 204 for (reg = 0; reg < 3; reg++) 205 PACK64(ptr, regs->gpr[reg]); 206 207 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 208 ptr += 11; 209 210 /* Regs GPR14-31 */ 211 for (reg = 14; reg < 32; reg++) 212 PACK64(ptr, regs->gpr[reg]); 213 214#ifdef CONFIG_FSL_BOOKE 215#ifdef CONFIG_SPE 216 for (reg = 0; reg < 32; reg++) 217 PACK64(ptr, p->thread.evr[reg]); 218#else 219 ptr += 32; 220#endif 221#else 222 /* fp registers not used by kernel, leave zero */ 223 ptr += 32 * 8 / sizeof(long); 224#endif 225 226 PACK64(ptr, regs->nip); 227 PACK64(ptr, regs->msr); 228 PACK32(ptr, regs->ccr); 229 PACK64(ptr, regs->link); 230 PACK64(ptr, regs->ctr); 231 PACK32(ptr, regs->xer); 232 233 BUG_ON((unsigned long)ptr > 234 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 235} 236 237#define GDB_SIZEOF_REG sizeof(unsigned long) 238#define GDB_SIZEOF_REG_U32 sizeof(u32) 239 240#ifdef CONFIG_FSL_BOOKE 241#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long) 242#else 243#define GDB_SIZEOF_FLOAT_REG sizeof(u64) 244#endif 245 246struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 247{ 248 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) }, 249 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) }, 250 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) }, 251 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) }, 252 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) }, 253 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) }, 254 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) }, 255 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) }, 256 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) }, 257 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) }, 258 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) }, 259 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) }, 260 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) }, 261 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) }, 262 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) }, 263 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) }, 264 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) }, 265 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) }, 266 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) }, 267 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) }, 268 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) }, 269 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) }, 270 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) }, 271 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) }, 272 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) }, 273 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) }, 274 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) }, 275 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) }, 276 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) }, 277 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) }, 278 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) }, 279 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) }, 280 281 { "f0", GDB_SIZEOF_FLOAT_REG, 0 }, 282 { "f1", GDB_SIZEOF_FLOAT_REG, 1 }, 283 { "f2", GDB_SIZEOF_FLOAT_REG, 2 }, 284 { "f3", GDB_SIZEOF_FLOAT_REG, 3 }, 285 { "f4", GDB_SIZEOF_FLOAT_REG, 4 }, 286 { "f5", GDB_SIZEOF_FLOAT_REG, 5 }, 287 { "f6", GDB_SIZEOF_FLOAT_REG, 6 }, 288 { "f7", GDB_SIZEOF_FLOAT_REG, 7 }, 289 { "f8", GDB_SIZEOF_FLOAT_REG, 8 }, 290 { "f9", GDB_SIZEOF_FLOAT_REG, 9 }, 291 { "f10", GDB_SIZEOF_FLOAT_REG, 10 }, 292 { "f11", GDB_SIZEOF_FLOAT_REG, 11 }, 293 { "f12", GDB_SIZEOF_FLOAT_REG, 12 }, 294 { "f13", GDB_SIZEOF_FLOAT_REG, 13 }, 295 { "f14", GDB_SIZEOF_FLOAT_REG, 14 }, 296 { "f15", GDB_SIZEOF_FLOAT_REG, 15 }, 297 { "f16", GDB_SIZEOF_FLOAT_REG, 16 }, 298 { "f17", GDB_SIZEOF_FLOAT_REG, 17 }, 299 { "f18", GDB_SIZEOF_FLOAT_REG, 18 }, 300 { "f19", GDB_SIZEOF_FLOAT_REG, 19 }, 301 { "f20", GDB_SIZEOF_FLOAT_REG, 20 }, 302 { "f21", GDB_SIZEOF_FLOAT_REG, 21 }, 303 { "f22", GDB_SIZEOF_FLOAT_REG, 22 }, 304 { "f23", GDB_SIZEOF_FLOAT_REG, 23 }, 305 { "f24", GDB_SIZEOF_FLOAT_REG, 24 }, 306 { "f25", GDB_SIZEOF_FLOAT_REG, 25 }, 307 { "f26", GDB_SIZEOF_FLOAT_REG, 26 }, 308 { "f27", GDB_SIZEOF_FLOAT_REG, 27 }, 309 { "f28", GDB_SIZEOF_FLOAT_REG, 28 }, 310 { "f29", GDB_SIZEOF_FLOAT_REG, 29 }, 311 { "f30", GDB_SIZEOF_FLOAT_REG, 30 }, 312 { "f31", GDB_SIZEOF_FLOAT_REG, 31 }, 313 314 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) }, 315 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) }, 316 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) }, 317 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) }, 318 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) }, 319 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) }, 320}; 321 322char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 323{ 324 if (regno >= DBG_MAX_REG_NUM || regno < 0) 325 return NULL; 326 327 if (regno < 32 || regno >= 64) 328 /* First 0 -> 31 gpr registers*/ 329 /* pc, msr, ls... registers 64 -> 69 */ 330 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 331 dbg_reg_def[regno].size); 332 333 if (regno >= 32 && regno < 64) { 334 /* FP registers 32 -> 63 */ 335#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 336 if (current) 337 memcpy(mem, ¤t->thread.evr[regno-32], 338 dbg_reg_def[regno].size); 339#else 340 /* fp registers not used by kernel, leave zero */ 341 memset(mem, 0, dbg_reg_def[regno].size); 342#endif 343 } 344 345 return dbg_reg_def[regno].name; 346} 347 348int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 349{ 350 if (regno >= DBG_MAX_REG_NUM || regno < 0) 351 return -EINVAL; 352 353 if (regno < 32 || regno >= 64) 354 /* First 0 -> 31 gpr registers*/ 355 /* pc, msr, ls... registers 64 -> 69 */ 356 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 357 dbg_reg_def[regno].size); 358 359 if (regno >= 32 && regno < 64) { 360 /* FP registers 32 -> 63 */ 361#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 362 memcpy(¤t->thread.evr[regno-32], mem, 363 dbg_reg_def[regno].size); 364#else 365 /* fp registers not used by kernel, leave zero */ 366 return 0; 367#endif 368 } 369 370 return 0; 371} 372 373void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 374{ 375 regs_set_return_ip(regs, pc); 376} 377 378/* 379 * This function does PowerPC specific processing for interfacing to gdb. 380 */ 381int kgdb_arch_handle_exception(int vector, int signo, int err_code, 382 char *remcom_in_buffer, char *remcom_out_buffer, 383 struct pt_regs *linux_regs) 384{ 385 char *ptr = &remcom_in_buffer[1]; 386 unsigned long addr; 387 388 switch (remcom_in_buffer[0]) { 389 /* 390 * sAA..AA Step one instruction from AA..AA 391 * This will return an error to gdb .. 392 */ 393 case 's': 394 case 'c': 395 /* handle the optional parameter */ 396 if (kgdb_hex2long(&ptr, &addr)) 397 regs_set_return_ip(linux_regs, addr); 398 399 atomic_set(&kgdb_cpu_doing_single_step, -1); 400 /* set the trace bit if we're stepping */ 401 if (remcom_in_buffer[0] == 's') { 402#ifdef CONFIG_PPC_ADV_DEBUG_REGS 403 mtspr(SPRN_DBCR0, 404 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 405 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE); 406#else 407 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE); 408#endif 409 atomic_set(&kgdb_cpu_doing_single_step, 410 raw_smp_processor_id()); 411 } 412 return 0; 413 } 414 415 return -1; 416} 417 418int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 419{ 420 u32 instr, *addr = (u32 *)bpt->bpt_addr; 421 int err; 422 423 err = get_kernel_nofault(instr, addr); 424 if (err) 425 return err; 426 427 err = patch_instruction(addr, ppc_inst(BREAK_INSTR)); 428 if (err) 429 return -EFAULT; 430 431 *(u32 *)bpt->saved_instr = instr; 432 433 return 0; 434} 435 436int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) 437{ 438 int err; 439 unsigned int instr = *(unsigned int *)bpt->saved_instr; 440 u32 *addr = (u32 *)bpt->bpt_addr; 441 442 err = patch_instruction(addr, ppc_inst(instr)); 443 if (err) 444 return -EFAULT; 445 446 return 0; 447} 448 449/* 450 * Global data 451 */ 452const struct kgdb_arch arch_kgdb_ops; 453 454static int kgdb_not_implemented(struct pt_regs *regs) 455{ 456 return 0; 457} 458 459static void *old__debugger_ipi; 460static void *old__debugger; 461static void *old__debugger_bpt; 462static void *old__debugger_sstep; 463static void *old__debugger_iabr_match; 464static void *old__debugger_break_match; 465static void *old__debugger_fault_handler; 466 467int 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 488void 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}