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/init.h> 19 #include <linux/kgdb.h> 20 #include <linux/smp.h> 21 #include <linux/signal.h> 22 #include <linux/ptrace.h> 23 #include <linux/kdebug.h> 24 #include <asm/current.h> 25 #include <asm/processor.h> 26 #include <asm/machdep.h> 27 28 /* 29 * This table contains the mapping between PowerPC hardware trap types, and 30 * signals, which are primarily what GDB understands. GDB and the kernel 31 * don't always agree on values, so we use constants taken from gdb-6.2. 32 */ 33 static struct hard_trap_info 34 { 35 unsigned int tt; /* Trap type code for powerpc */ 36 unsigned char signo; /* Signal that we map this trap into */ 37 } hard_trap_info[] = { 38 { 0x0100, 0x02 /* SIGINT */ }, /* system reset */ 39 { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */ 40 { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */ 41 { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */ 42 { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */ 43 { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */ 44 { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */ 45 { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */ 46 { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */ 47 { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */ 48 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) 49 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */ 50 #if defined(CONFIG_FSL_BOOKE) 51 { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */ 52 { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */ 53 { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */ 54 { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */ 55 { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */ 56 { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */ 57 { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */ 58 { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 59 { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */ 60 #else /* ! CONFIG_FSL_BOOKE */ 61 { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */ 62 { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */ 63 { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */ 64 { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */ 65 { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */ 66 #endif 67 #else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */ 68 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */ 69 #if defined(CONFIG_8xx) 70 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */ 71 #else /* ! CONFIG_8xx */ 72 { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */ 73 { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */ 74 { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */ 75 #if defined(CONFIG_PPC64) 76 { 0x1200, 0x05 /* SIGILL */ }, /* system error */ 77 { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */ 78 { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */ 79 { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */ 80 { 0x1800, 0x04 /* SIGILL */ }, /* thermal */ 81 #else /* ! CONFIG_PPC64 */ 82 { 0x1400, 0x02 /* SIGINT */ }, /* SMI */ 83 { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */ 84 { 0x1700, 0x04 /* SIGILL */ }, /* TAU */ 85 { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */ 86 #endif 87 #endif 88 #endif 89 { 0x0000, 0x00 } /* Must be last */ 90 }; 91 92 static int computeSignal(unsigned int tt) 93 { 94 struct hard_trap_info *ht; 95 96 for (ht = hard_trap_info; ht->tt && ht->signo; ht++) 97 if (ht->tt == tt) 98 return ht->signo; 99 100 return SIGHUP; /* default for things we don't know about */ 101 } 102 103 static int kgdb_call_nmi_hook(struct pt_regs *regs) 104 { 105 kgdb_nmicallback(raw_smp_processor_id(), regs); 106 return 0; 107 } 108 109 #ifdef CONFIG_SMP 110 void kgdb_roundup_cpus(unsigned long flags) 111 { 112 smp_send_debugger_break(MSG_ALL_BUT_SELF); 113 } 114 #endif 115 116 /* KGDB functions to use existing PowerPC64 hooks. */ 117 static int kgdb_debugger(struct pt_regs *regs) 118 { 119 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), 120 DIE_OOPS, regs); 121 } 122 123 static int kgdb_handle_breakpoint(struct pt_regs *regs) 124 { 125 if (user_mode(regs)) 126 return 0; 127 128 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) 129 return 0; 130 131 if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr)) 132 regs->nip += BREAK_INSTR_SIZE; 133 134 return 1; 135 } 136 137 static int kgdb_singlestep(struct pt_regs *regs) 138 { 139 struct thread_info *thread_info, *exception_thread_info; 140 141 if (user_mode(regs)) 142 return 0; 143 144 /* 145 * On Book E and perhaps other processsors, singlestep is handled on 146 * the critical exception stack. This causes current_thread_info() 147 * to fail, since it it locates the thread_info by masking off 148 * the low bits of the current stack pointer. We work around 149 * this issue by copying the thread_info from the kernel stack 150 * before calling kgdb_handle_exception, and copying it back 151 * afterwards. On most processors the copy is avoided since 152 * exception_thread_info == thread_info. 153 */ 154 thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); 155 exception_thread_info = current_thread_info(); 156 157 if (thread_info != exception_thread_info) 158 memcpy(exception_thread_info, thread_info, sizeof *thread_info); 159 160 kgdb_handle_exception(0, SIGTRAP, 0, regs); 161 162 if (thread_info != exception_thread_info) 163 memcpy(thread_info, exception_thread_info, sizeof *thread_info); 164 165 return 1; 166 } 167 168 static int kgdb_iabr_match(struct pt_regs *regs) 169 { 170 if (user_mode(regs)) 171 return 0; 172 173 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 174 return 0; 175 return 1; 176 } 177 178 static int kgdb_dabr_match(struct pt_regs *regs) 179 { 180 if (user_mode(regs)) 181 return 0; 182 183 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 184 return 0; 185 return 1; 186 } 187 188 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) 189 190 #define PACK32(ptr, src) do { \ 191 u32 *ptr32; \ 192 ptr32 = (u32 *)ptr; \ 193 *(ptr32++) = (src); \ 194 ptr = (unsigned long *)ptr32; \ 195 } while (0) 196 197 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 198 { 199 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 200 STACK_FRAME_OVERHEAD); 201 unsigned long *ptr = gdb_regs; 202 int reg; 203 204 memset(gdb_regs, 0, NUMREGBYTES); 205 206 /* Regs GPR0-2 */ 207 for (reg = 0; reg < 3; reg++) 208 PACK64(ptr, regs->gpr[reg]); 209 210 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 211 ptr += 11; 212 213 /* Regs GPR14-31 */ 214 for (reg = 14; reg < 32; reg++) 215 PACK64(ptr, regs->gpr[reg]); 216 217 #ifdef CONFIG_FSL_BOOKE 218 #ifdef CONFIG_SPE 219 for (reg = 0; reg < 32; reg++) 220 PACK64(ptr, p->thread.evr[reg]); 221 #else 222 ptr += 32; 223 #endif 224 #else 225 /* fp registers not used by kernel, leave zero */ 226 ptr += 32 * 8 / sizeof(long); 227 #endif 228 229 PACK64(ptr, regs->nip); 230 PACK64(ptr, regs->msr); 231 PACK32(ptr, regs->ccr); 232 PACK64(ptr, regs->link); 233 PACK64(ptr, regs->ctr); 234 PACK32(ptr, regs->xer); 235 236 BUG_ON((unsigned long)ptr > 237 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 238 } 239 240 #define GDB_SIZEOF_REG sizeof(unsigned long) 241 #define GDB_SIZEOF_REG_U32 sizeof(u32) 242 243 #ifdef CONFIG_FSL_BOOKE 244 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long) 245 #else 246 #define GDB_SIZEOF_FLOAT_REG sizeof(u64) 247 #endif 248 249 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 250 { 251 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) }, 252 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) }, 253 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) }, 254 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) }, 255 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) }, 256 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) }, 257 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) }, 258 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) }, 259 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) }, 260 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) }, 261 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) }, 262 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) }, 263 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) }, 264 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) }, 265 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) }, 266 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) }, 267 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) }, 268 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) }, 269 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) }, 270 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) }, 271 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) }, 272 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) }, 273 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) }, 274 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) }, 275 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) }, 276 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) }, 277 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) }, 278 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) }, 279 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) }, 280 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) }, 281 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) }, 282 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) }, 283 284 { "f0", GDB_SIZEOF_FLOAT_REG, 0 }, 285 { "f1", GDB_SIZEOF_FLOAT_REG, 1 }, 286 { "f2", GDB_SIZEOF_FLOAT_REG, 2 }, 287 { "f3", GDB_SIZEOF_FLOAT_REG, 3 }, 288 { "f4", GDB_SIZEOF_FLOAT_REG, 4 }, 289 { "f5", GDB_SIZEOF_FLOAT_REG, 5 }, 290 { "f6", GDB_SIZEOF_FLOAT_REG, 6 }, 291 { "f7", GDB_SIZEOF_FLOAT_REG, 7 }, 292 { "f8", GDB_SIZEOF_FLOAT_REG, 8 }, 293 { "f9", GDB_SIZEOF_FLOAT_REG, 9 }, 294 { "f10", GDB_SIZEOF_FLOAT_REG, 10 }, 295 { "f11", GDB_SIZEOF_FLOAT_REG, 11 }, 296 { "f12", GDB_SIZEOF_FLOAT_REG, 12 }, 297 { "f13", GDB_SIZEOF_FLOAT_REG, 13 }, 298 { "f14", GDB_SIZEOF_FLOAT_REG, 14 }, 299 { "f15", GDB_SIZEOF_FLOAT_REG, 15 }, 300 { "f16", GDB_SIZEOF_FLOAT_REG, 16 }, 301 { "f17", GDB_SIZEOF_FLOAT_REG, 17 }, 302 { "f18", GDB_SIZEOF_FLOAT_REG, 18 }, 303 { "f19", GDB_SIZEOF_FLOAT_REG, 19 }, 304 { "f20", GDB_SIZEOF_FLOAT_REG, 20 }, 305 { "f21", GDB_SIZEOF_FLOAT_REG, 21 }, 306 { "f22", GDB_SIZEOF_FLOAT_REG, 22 }, 307 { "f23", GDB_SIZEOF_FLOAT_REG, 23 }, 308 { "f24", GDB_SIZEOF_FLOAT_REG, 24 }, 309 { "f25", GDB_SIZEOF_FLOAT_REG, 25 }, 310 { "f26", GDB_SIZEOF_FLOAT_REG, 26 }, 311 { "f27", GDB_SIZEOF_FLOAT_REG, 27 }, 312 { "f28", GDB_SIZEOF_FLOAT_REG, 28 }, 313 { "f29", GDB_SIZEOF_FLOAT_REG, 29 }, 314 { "f30", GDB_SIZEOF_FLOAT_REG, 30 }, 315 { "f31", GDB_SIZEOF_FLOAT_REG, 31 }, 316 317 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) }, 318 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) }, 319 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) }, 320 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) }, 321 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) }, 322 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) }, 323 }; 324 325 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 326 { 327 if (regno >= DBG_MAX_REG_NUM || regno < 0) 328 return NULL; 329 330 if (regno < 32 || regno >= 64) 331 /* First 0 -> 31 gpr registers*/ 332 /* pc, msr, ls... registers 64 -> 69 */ 333 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 334 dbg_reg_def[regno].size); 335 336 if (regno >= 32 && regno < 64) { 337 /* FP registers 32 -> 63 */ 338 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 339 if (current) 340 memcpy(mem, ¤t->thread.evr[regno-32], 341 dbg_reg_def[regno].size); 342 #else 343 /* fp registers not used by kernel, leave zero */ 344 memset(mem, 0, dbg_reg_def[regno].size); 345 #endif 346 } 347 348 return dbg_reg_def[regno].name; 349 } 350 351 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 352 { 353 if (regno >= DBG_MAX_REG_NUM || regno < 0) 354 return -EINVAL; 355 356 if (regno < 32 || regno >= 64) 357 /* First 0 -> 31 gpr registers*/ 358 /* pc, msr, ls... registers 64 -> 69 */ 359 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 360 dbg_reg_def[regno].size); 361 362 if (regno >= 32 && regno < 64) { 363 /* FP registers 32 -> 63 */ 364 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 365 memcpy(¤t->thread.evr[regno-32], mem, 366 dbg_reg_def[regno].size); 367 #else 368 /* fp registers not used by kernel, leave zero */ 369 return 0; 370 #endif 371 } 372 373 return 0; 374 } 375 376 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 377 { 378 regs->nip = pc; 379 } 380 381 /* 382 * This function does PowerPC specific procesing for interfacing to gdb. 383 */ 384 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 385 char *remcom_in_buffer, char *remcom_out_buffer, 386 struct pt_regs *linux_regs) 387 { 388 char *ptr = &remcom_in_buffer[1]; 389 unsigned long addr; 390 391 switch (remcom_in_buffer[0]) { 392 /* 393 * sAA..AA Step one instruction from AA..AA 394 * This will return an error to gdb .. 395 */ 396 case 's': 397 case 'c': 398 /* handle the optional parameter */ 399 if (kgdb_hex2long(&ptr, &addr)) 400 linux_regs->nip = addr; 401 402 atomic_set(&kgdb_cpu_doing_single_step, -1); 403 /* set the trace bit if we're stepping */ 404 if (remcom_in_buffer[0] == 's') { 405 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 406 mtspr(SPRN_DBCR0, 407 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 408 linux_regs->msr |= MSR_DE; 409 #else 410 linux_regs->msr |= MSR_SE; 411 #endif 412 kgdb_single_step = 1; 413 atomic_set(&kgdb_cpu_doing_single_step, 414 raw_smp_processor_id()); 415 } 416 return 0; 417 } 418 419 return -1; 420 } 421 422 /* 423 * Global data 424 */ 425 struct kgdb_arch arch_kgdb_ops = { 426 .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08}, 427 }; 428 429 static int kgdb_not_implemented(struct pt_regs *regs) 430 { 431 return 0; 432 } 433 434 static void *old__debugger_ipi; 435 static void *old__debugger; 436 static void *old__debugger_bpt; 437 static void *old__debugger_sstep; 438 static void *old__debugger_iabr_match; 439 static void *old__debugger_dabr_match; 440 static void *old__debugger_fault_handler; 441 442 int kgdb_arch_init(void) 443 { 444 old__debugger_ipi = __debugger_ipi; 445 old__debugger = __debugger; 446 old__debugger_bpt = __debugger_bpt; 447 old__debugger_sstep = __debugger_sstep; 448 old__debugger_iabr_match = __debugger_iabr_match; 449 old__debugger_dabr_match = __debugger_dabr_match; 450 old__debugger_fault_handler = __debugger_fault_handler; 451 452 __debugger_ipi = kgdb_call_nmi_hook; 453 __debugger = kgdb_debugger; 454 __debugger_bpt = kgdb_handle_breakpoint; 455 __debugger_sstep = kgdb_singlestep; 456 __debugger_iabr_match = kgdb_iabr_match; 457 __debugger_dabr_match = kgdb_dabr_match; 458 __debugger_fault_handler = kgdb_not_implemented; 459 460 return 0; 461 } 462 463 void kgdb_arch_exit(void) 464 { 465 __debugger_ipi = old__debugger_ipi; 466 __debugger = old__debugger; 467 __debugger_bpt = old__debugger_bpt; 468 __debugger_sstep = old__debugger_sstep; 469 __debugger_iabr_match = old__debugger_iabr_match; 470 __debugger_dabr_match = old__debugger_dabr_match; 471 __debugger_fault_handler = old__debugger_fault_handler; 472 } 473