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 <linux/slab.h> 28 29/* 30 * This table contains the mapping between PowerPC hardware trap types, and 31 * signals, which are primarily what GDB understands. GDB and the kernel 32 * don't always agree on values, so we use constants taken from gdb-6.2. 33 */ 34static struct hard_trap_info 35{ 36 unsigned int tt; /* Trap type code for powerpc */ 37 unsigned char signo; /* Signal that we map this trap into */ 38} hard_trap_info[] = { 39 { 0x0100, 0x02 /* SIGINT */ }, /* system reset */ 40 { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */ 41 { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */ 42 { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */ 43 { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */ 44 { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */ 45 { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */ 46 { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */ 47 { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */ 48 { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */ 49#if defined(CONFIG_40x) || defined(CONFIG_BOOKE) 50 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */ 51#if defined(CONFIG_FSL_BOOKE) 52 { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */ 53 { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */ 54 { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */ 55 { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */ 56 { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */ 57 { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */ 58 { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */ 59 { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 60 { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */ 61#else /* ! CONFIG_FSL_BOOKE */ 62 { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */ 63 { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 64 { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */ 65 { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */ 66 { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */ 67#endif 68#else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */ 69 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */ 70#if defined(CONFIG_8xx) 71 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */ 72#else /* ! CONFIG_8xx */ 73 { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */ 74 { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */ 75 { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */ 76#if defined(CONFIG_PPC64) 77 { 0x1200, 0x05 /* SIGILL */ }, /* system error */ 78 { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */ 79 { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */ 80 { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */ 81 { 0x1800, 0x04 /* SIGILL */ }, /* thermal */ 82#else /* ! CONFIG_PPC64 */ 83 { 0x1400, 0x02 /* SIGINT */ }, /* SMI */ 84 { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */ 85 { 0x1700, 0x04 /* SIGILL */ }, /* TAU */ 86 { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */ 87#endif 88#endif 89#endif 90 { 0x0000, 0x00 } /* Must be last */ 91}; 92 93static int computeSignal(unsigned int tt) 94{ 95 struct hard_trap_info *ht; 96 97 for (ht = hard_trap_info; ht->tt && ht->signo; ht++) 98 if (ht->tt == tt) 99 return ht->signo; 100 101 return SIGHUP; /* default for things we don't know about */ 102} 103 104/** 105 * 106 * kgdb_skipexception - Bail out of KGDB when we've been triggered. 107 * @exception: Exception vector number 108 * @regs: Current &struct pt_regs. 109 * 110 * On some architectures we need to skip a breakpoint exception when 111 * it occurs after a breakpoint has been removed. 112 * 113 */ 114int kgdb_skipexception(int exception, struct pt_regs *regs) 115{ 116 return kgdb_isremovedbreak(regs->nip); 117} 118 119static int kgdb_call_nmi_hook(struct pt_regs *regs) 120{ 121 kgdb_nmicallback(raw_smp_processor_id(), regs); 122 return 0; 123} 124 125#ifdef CONFIG_SMP 126void kgdb_roundup_cpus(unsigned long flags) 127{ 128 smp_send_debugger_break(); 129} 130#endif 131 132/* KGDB functions to use existing PowerPC64 hooks. */ 133static int kgdb_debugger(struct pt_regs *regs) 134{ 135 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), 136 DIE_OOPS, regs); 137} 138 139static int kgdb_handle_breakpoint(struct pt_regs *regs) 140{ 141 if (user_mode(regs)) 142 return 0; 143 144 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) 145 return 0; 146 147 if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr)) 148 regs->nip += BREAK_INSTR_SIZE; 149 150 return 1; 151} 152 153static DEFINE_PER_CPU(struct thread_info, kgdb_thread_info); 154static int kgdb_singlestep(struct pt_regs *regs) 155{ 156 struct thread_info *thread_info, *exception_thread_info; 157 struct thread_info *backup_current_thread_info = 158 &__get_cpu_var(kgdb_thread_info); 159 160 if (user_mode(regs)) 161 return 0; 162 163 /* 164 * On Book E and perhaps other processors, singlestep is handled on 165 * the critical exception stack. This causes current_thread_info() 166 * to fail, since it it locates the thread_info by masking off 167 * the low bits of the current stack pointer. We work around 168 * this issue by copying the thread_info from the kernel stack 169 * before calling kgdb_handle_exception, and copying it back 170 * afterwards. On most processors the copy is avoided since 171 * exception_thread_info == thread_info. 172 */ 173 thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); 174 exception_thread_info = current_thread_info(); 175 176 if (thread_info != exception_thread_info) { 177 /* Save the original current_thread_info. */ 178 memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info); 179 memcpy(exception_thread_info, thread_info, sizeof *thread_info); 180 } 181 182 kgdb_handle_exception(0, SIGTRAP, 0, regs); 183 184 if (thread_info != exception_thread_info) 185 /* Restore current_thread_info lastly. */ 186 memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); 187 188 return 1; 189} 190 191static int kgdb_iabr_match(struct pt_regs *regs) 192{ 193 if (user_mode(regs)) 194 return 0; 195 196 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 197 return 0; 198 return 1; 199} 200 201static int kgdb_break_match(struct pt_regs *regs) 202{ 203 if (user_mode(regs)) 204 return 0; 205 206 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 207 return 0; 208 return 1; 209} 210 211#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) 212 213#define PACK32(ptr, src) do { \ 214 u32 *ptr32; \ 215 ptr32 = (u32 *)ptr; \ 216 *(ptr32++) = (src); \ 217 ptr = (unsigned long *)ptr32; \ 218 } while (0) 219 220void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 221{ 222 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 223 STACK_FRAME_OVERHEAD); 224 unsigned long *ptr = gdb_regs; 225 int reg; 226 227 memset(gdb_regs, 0, NUMREGBYTES); 228 229 /* Regs GPR0-2 */ 230 for (reg = 0; reg < 3; reg++) 231 PACK64(ptr, regs->gpr[reg]); 232 233 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 234 ptr += 11; 235 236 /* Regs GPR14-31 */ 237 for (reg = 14; reg < 32; reg++) 238 PACK64(ptr, regs->gpr[reg]); 239 240#ifdef CONFIG_FSL_BOOKE 241#ifdef CONFIG_SPE 242 for (reg = 0; reg < 32; reg++) 243 PACK64(ptr, p->thread.evr[reg]); 244#else 245 ptr += 32; 246#endif 247#else 248 /* fp registers not used by kernel, leave zero */ 249 ptr += 32 * 8 / sizeof(long); 250#endif 251 252 PACK64(ptr, regs->nip); 253 PACK64(ptr, regs->msr); 254 PACK32(ptr, regs->ccr); 255 PACK64(ptr, regs->link); 256 PACK64(ptr, regs->ctr); 257 PACK32(ptr, regs->xer); 258 259 BUG_ON((unsigned long)ptr > 260 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 261} 262 263#define GDB_SIZEOF_REG sizeof(unsigned long) 264#define GDB_SIZEOF_REG_U32 sizeof(u32) 265 266#ifdef CONFIG_FSL_BOOKE 267#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long) 268#else 269#define GDB_SIZEOF_FLOAT_REG sizeof(u64) 270#endif 271 272struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 273{ 274 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) }, 275 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) }, 276 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) }, 277 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) }, 278 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) }, 279 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) }, 280 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) }, 281 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) }, 282 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) }, 283 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) }, 284 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) }, 285 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) }, 286 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) }, 287 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) }, 288 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) }, 289 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) }, 290 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) }, 291 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) }, 292 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) }, 293 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) }, 294 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) }, 295 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) }, 296 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) }, 297 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) }, 298 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) }, 299 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) }, 300 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) }, 301 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) }, 302 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) }, 303 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) }, 304 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) }, 305 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) }, 306 307 { "f0", GDB_SIZEOF_FLOAT_REG, 0 }, 308 { "f1", GDB_SIZEOF_FLOAT_REG, 1 }, 309 { "f2", GDB_SIZEOF_FLOAT_REG, 2 }, 310 { "f3", GDB_SIZEOF_FLOAT_REG, 3 }, 311 { "f4", GDB_SIZEOF_FLOAT_REG, 4 }, 312 { "f5", GDB_SIZEOF_FLOAT_REG, 5 }, 313 { "f6", GDB_SIZEOF_FLOAT_REG, 6 }, 314 { "f7", GDB_SIZEOF_FLOAT_REG, 7 }, 315 { "f8", GDB_SIZEOF_FLOAT_REG, 8 }, 316 { "f9", GDB_SIZEOF_FLOAT_REG, 9 }, 317 { "f10", GDB_SIZEOF_FLOAT_REG, 10 }, 318 { "f11", GDB_SIZEOF_FLOAT_REG, 11 }, 319 { "f12", GDB_SIZEOF_FLOAT_REG, 12 }, 320 { "f13", GDB_SIZEOF_FLOAT_REG, 13 }, 321 { "f14", GDB_SIZEOF_FLOAT_REG, 14 }, 322 { "f15", GDB_SIZEOF_FLOAT_REG, 15 }, 323 { "f16", GDB_SIZEOF_FLOAT_REG, 16 }, 324 { "f17", GDB_SIZEOF_FLOAT_REG, 17 }, 325 { "f18", GDB_SIZEOF_FLOAT_REG, 18 }, 326 { "f19", GDB_SIZEOF_FLOAT_REG, 19 }, 327 { "f20", GDB_SIZEOF_FLOAT_REG, 20 }, 328 { "f21", GDB_SIZEOF_FLOAT_REG, 21 }, 329 { "f22", GDB_SIZEOF_FLOAT_REG, 22 }, 330 { "f23", GDB_SIZEOF_FLOAT_REG, 23 }, 331 { "f24", GDB_SIZEOF_FLOAT_REG, 24 }, 332 { "f25", GDB_SIZEOF_FLOAT_REG, 25 }, 333 { "f26", GDB_SIZEOF_FLOAT_REG, 26 }, 334 { "f27", GDB_SIZEOF_FLOAT_REG, 27 }, 335 { "f28", GDB_SIZEOF_FLOAT_REG, 28 }, 336 { "f29", GDB_SIZEOF_FLOAT_REG, 29 }, 337 { "f30", GDB_SIZEOF_FLOAT_REG, 30 }, 338 { "f31", GDB_SIZEOF_FLOAT_REG, 31 }, 339 340 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) }, 341 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) }, 342 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) }, 343 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) }, 344 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) }, 345 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) }, 346}; 347 348char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 349{ 350 if (regno >= DBG_MAX_REG_NUM || regno < 0) 351 return NULL; 352 353 if (regno < 32 || regno >= 64) 354 /* First 0 -> 31 gpr registers*/ 355 /* pc, msr, ls... registers 64 -> 69 */ 356 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 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 if (current) 363 memcpy(mem, ¤t->thread.evr[regno-32], 364 dbg_reg_def[regno].size); 365#else 366 /* fp registers not used by kernel, leave zero */ 367 memset(mem, 0, dbg_reg_def[regno].size); 368#endif 369 } 370 371 return dbg_reg_def[regno].name; 372} 373 374int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 375{ 376 if (regno >= DBG_MAX_REG_NUM || regno < 0) 377 return -EINVAL; 378 379 if (regno < 32 || regno >= 64) 380 /* First 0 -> 31 gpr registers*/ 381 /* pc, msr, ls... registers 64 -> 69 */ 382 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 383 dbg_reg_def[regno].size); 384 385 if (regno >= 32 && regno < 64) { 386 /* FP registers 32 -> 63 */ 387#if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 388 memcpy(¤t->thread.evr[regno-32], mem, 389 dbg_reg_def[regno].size); 390#else 391 /* fp registers not used by kernel, leave zero */ 392 return 0; 393#endif 394 } 395 396 return 0; 397} 398 399void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 400{ 401 regs->nip = pc; 402} 403 404/* 405 * This function does PowerPC specific procesing for interfacing to gdb. 406 */ 407int kgdb_arch_handle_exception(int vector, int signo, int err_code, 408 char *remcom_in_buffer, char *remcom_out_buffer, 409 struct pt_regs *linux_regs) 410{ 411 char *ptr = &remcom_in_buffer[1]; 412 unsigned long addr; 413 414 switch (remcom_in_buffer[0]) { 415 /* 416 * sAA..AA Step one instruction from AA..AA 417 * This will return an error to gdb .. 418 */ 419 case 's': 420 case 'c': 421 /* handle the optional parameter */ 422 if (kgdb_hex2long(&ptr, &addr)) 423 linux_regs->nip = addr; 424 425 atomic_set(&kgdb_cpu_doing_single_step, -1); 426 /* set the trace bit if we're stepping */ 427 if (remcom_in_buffer[0] == 's') { 428#ifdef CONFIG_PPC_ADV_DEBUG_REGS 429 mtspr(SPRN_DBCR0, 430 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 431 linux_regs->msr |= MSR_DE; 432#else 433 linux_regs->msr |= MSR_SE; 434#endif 435 atomic_set(&kgdb_cpu_doing_single_step, 436 raw_smp_processor_id()); 437 } 438 return 0; 439 } 440 441 return -1; 442} 443 444/* 445 * Global data 446 */ 447struct kgdb_arch arch_kgdb_ops = { 448 .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08}, 449}; 450 451static int kgdb_not_implemented(struct pt_regs *regs) 452{ 453 return 0; 454} 455 456static void *old__debugger_ipi; 457static void *old__debugger; 458static void *old__debugger_bpt; 459static void *old__debugger_sstep; 460static void *old__debugger_iabr_match; 461static void *old__debugger_break_match; 462static void *old__debugger_fault_handler; 463 464int kgdb_arch_init(void) 465{ 466 old__debugger_ipi = __debugger_ipi; 467 old__debugger = __debugger; 468 old__debugger_bpt = __debugger_bpt; 469 old__debugger_sstep = __debugger_sstep; 470 old__debugger_iabr_match = __debugger_iabr_match; 471 old__debugger_break_match = __debugger_break_match; 472 old__debugger_fault_handler = __debugger_fault_handler; 473 474 __debugger_ipi = kgdb_call_nmi_hook; 475 __debugger = kgdb_debugger; 476 __debugger_bpt = kgdb_handle_breakpoint; 477 __debugger_sstep = kgdb_singlestep; 478 __debugger_iabr_match = kgdb_iabr_match; 479 __debugger_break_match = kgdb_break_match; 480 __debugger_fault_handler = kgdb_not_implemented; 481 482 return 0; 483} 484 485void kgdb_arch_exit(void) 486{ 487 __debugger_ipi = old__debugger_ipi; 488 __debugger = old__debugger; 489 __debugger_bpt = old__debugger_bpt; 490 __debugger_sstep = old__debugger_sstep; 491 __debugger_iabr_match = old__debugger_iabr_match; 492 __debugger_break_match = old__debugger_break_match; 493 __debugger_fault_handler = old__debugger_fault_handler; 494} 495