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 #include <asm/debug.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 */ 34 static 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 93 static 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 static int kgdb_call_nmi_hook(struct pt_regs *regs) 105 { 106 kgdb_nmicallback(raw_smp_processor_id(), regs); 107 return 0; 108 } 109 110 #ifdef CONFIG_SMP 111 void kgdb_roundup_cpus(unsigned long flags) 112 { 113 smp_send_debugger_break(); 114 } 115 #endif 116 117 /* KGDB functions to use existing PowerPC64 hooks. */ 118 static int kgdb_debugger(struct pt_regs *regs) 119 { 120 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), 121 DIE_OOPS, regs); 122 } 123 124 static int kgdb_handle_breakpoint(struct pt_regs *regs) 125 { 126 if (user_mode(regs)) 127 return 0; 128 129 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) 130 return 0; 131 132 if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr)) 133 regs->nip += BREAK_INSTR_SIZE; 134 135 return 1; 136 } 137 138 static int kgdb_singlestep(struct pt_regs *regs) 139 { 140 struct thread_info *thread_info, *exception_thread_info; 141 142 if (user_mode(regs)) 143 return 0; 144 145 /* 146 * On Book E and perhaps other processors, singlestep is handled on 147 * the critical exception stack. This causes current_thread_info() 148 * to fail, since it it locates the thread_info by masking off 149 * the low bits of the current stack pointer. We work around 150 * this issue by copying the thread_info from the kernel stack 151 * before calling kgdb_handle_exception, and copying it back 152 * afterwards. On most processors the copy is avoided since 153 * exception_thread_info == thread_info. 154 */ 155 thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); 156 exception_thread_info = current_thread_info(); 157 158 if (thread_info != exception_thread_info) 159 memcpy(exception_thread_info, thread_info, sizeof *thread_info); 160 161 kgdb_handle_exception(0, SIGTRAP, 0, regs); 162 163 if (thread_info != exception_thread_info) 164 memcpy(thread_info, exception_thread_info, sizeof *thread_info); 165 166 return 1; 167 } 168 169 static int kgdb_iabr_match(struct pt_regs *regs) 170 { 171 if (user_mode(regs)) 172 return 0; 173 174 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 175 return 0; 176 return 1; 177 } 178 179 static int kgdb_dabr_match(struct pt_regs *regs) 180 { 181 if (user_mode(regs)) 182 return 0; 183 184 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 185 return 0; 186 return 1; 187 } 188 189 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) 190 191 #define PACK32(ptr, src) do { \ 192 u32 *ptr32; \ 193 ptr32 = (u32 *)ptr; \ 194 *(ptr32++) = (src); \ 195 ptr = (unsigned long *)ptr32; \ 196 } while (0) 197 198 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 199 { 200 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 201 STACK_FRAME_OVERHEAD); 202 unsigned long *ptr = gdb_regs; 203 int reg; 204 205 memset(gdb_regs, 0, NUMREGBYTES); 206 207 /* Regs GPR0-2 */ 208 for (reg = 0; reg < 3; reg++) 209 PACK64(ptr, regs->gpr[reg]); 210 211 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 212 ptr += 11; 213 214 /* Regs GPR14-31 */ 215 for (reg = 14; reg < 32; reg++) 216 PACK64(ptr, regs->gpr[reg]); 217 218 #ifdef CONFIG_FSL_BOOKE 219 #ifdef CONFIG_SPE 220 for (reg = 0; reg < 32; reg++) 221 PACK64(ptr, p->thread.evr[reg]); 222 #else 223 ptr += 32; 224 #endif 225 #else 226 /* fp registers not used by kernel, leave zero */ 227 ptr += 32 * 8 / sizeof(long); 228 #endif 229 230 PACK64(ptr, regs->nip); 231 PACK64(ptr, regs->msr); 232 PACK32(ptr, regs->ccr); 233 PACK64(ptr, regs->link); 234 PACK64(ptr, regs->ctr); 235 PACK32(ptr, regs->xer); 236 237 BUG_ON((unsigned long)ptr > 238 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 239 } 240 241 #define GDB_SIZEOF_REG sizeof(unsigned long) 242 #define GDB_SIZEOF_REG_U32 sizeof(u32) 243 244 #ifdef CONFIG_FSL_BOOKE 245 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long) 246 #else 247 #define GDB_SIZEOF_FLOAT_REG sizeof(u64) 248 #endif 249 250 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 251 { 252 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) }, 253 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) }, 254 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) }, 255 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) }, 256 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) }, 257 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) }, 258 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) }, 259 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) }, 260 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) }, 261 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) }, 262 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) }, 263 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) }, 264 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) }, 265 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) }, 266 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) }, 267 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) }, 268 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) }, 269 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) }, 270 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) }, 271 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) }, 272 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) }, 273 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) }, 274 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) }, 275 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) }, 276 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) }, 277 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) }, 278 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) }, 279 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) }, 280 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) }, 281 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) }, 282 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) }, 283 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) }, 284 285 { "f0", GDB_SIZEOF_FLOAT_REG, 0 }, 286 { "f1", GDB_SIZEOF_FLOAT_REG, 1 }, 287 { "f2", GDB_SIZEOF_FLOAT_REG, 2 }, 288 { "f3", GDB_SIZEOF_FLOAT_REG, 3 }, 289 { "f4", GDB_SIZEOF_FLOAT_REG, 4 }, 290 { "f5", GDB_SIZEOF_FLOAT_REG, 5 }, 291 { "f6", GDB_SIZEOF_FLOAT_REG, 6 }, 292 { "f7", GDB_SIZEOF_FLOAT_REG, 7 }, 293 { "f8", GDB_SIZEOF_FLOAT_REG, 8 }, 294 { "f9", GDB_SIZEOF_FLOAT_REG, 9 }, 295 { "f10", GDB_SIZEOF_FLOAT_REG, 10 }, 296 { "f11", GDB_SIZEOF_FLOAT_REG, 11 }, 297 { "f12", GDB_SIZEOF_FLOAT_REG, 12 }, 298 { "f13", GDB_SIZEOF_FLOAT_REG, 13 }, 299 { "f14", GDB_SIZEOF_FLOAT_REG, 14 }, 300 { "f15", GDB_SIZEOF_FLOAT_REG, 15 }, 301 { "f16", GDB_SIZEOF_FLOAT_REG, 16 }, 302 { "f17", GDB_SIZEOF_FLOAT_REG, 17 }, 303 { "f18", GDB_SIZEOF_FLOAT_REG, 18 }, 304 { "f19", GDB_SIZEOF_FLOAT_REG, 19 }, 305 { "f20", GDB_SIZEOF_FLOAT_REG, 20 }, 306 { "f21", GDB_SIZEOF_FLOAT_REG, 21 }, 307 { "f22", GDB_SIZEOF_FLOAT_REG, 22 }, 308 { "f23", GDB_SIZEOF_FLOAT_REG, 23 }, 309 { "f24", GDB_SIZEOF_FLOAT_REG, 24 }, 310 { "f25", GDB_SIZEOF_FLOAT_REG, 25 }, 311 { "f26", GDB_SIZEOF_FLOAT_REG, 26 }, 312 { "f27", GDB_SIZEOF_FLOAT_REG, 27 }, 313 { "f28", GDB_SIZEOF_FLOAT_REG, 28 }, 314 { "f29", GDB_SIZEOF_FLOAT_REG, 29 }, 315 { "f30", GDB_SIZEOF_FLOAT_REG, 30 }, 316 { "f31", GDB_SIZEOF_FLOAT_REG, 31 }, 317 318 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) }, 319 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) }, 320 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) }, 321 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) }, 322 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) }, 323 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) }, 324 }; 325 326 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 327 { 328 if (regno >= DBG_MAX_REG_NUM || regno < 0) 329 return NULL; 330 331 if (regno < 32 || regno >= 64) 332 /* First 0 -> 31 gpr registers*/ 333 /* pc, msr, ls... registers 64 -> 69 */ 334 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 335 dbg_reg_def[regno].size); 336 337 if (regno >= 32 && regno < 64) { 338 /* FP registers 32 -> 63 */ 339 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 340 if (current) 341 memcpy(mem, ¤t->thread.evr[regno-32], 342 dbg_reg_def[regno].size); 343 #else 344 /* fp registers not used by kernel, leave zero */ 345 memset(mem, 0, dbg_reg_def[regno].size); 346 #endif 347 } 348 349 return dbg_reg_def[regno].name; 350 } 351 352 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 353 { 354 if (regno >= DBG_MAX_REG_NUM || regno < 0) 355 return -EINVAL; 356 357 if (regno < 32 || regno >= 64) 358 /* First 0 -> 31 gpr registers*/ 359 /* pc, msr, ls... registers 64 -> 69 */ 360 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 361 dbg_reg_def[regno].size); 362 363 if (regno >= 32 && regno < 64) { 364 /* FP registers 32 -> 63 */ 365 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE) 366 memcpy(¤t->thread.evr[regno-32], mem, 367 dbg_reg_def[regno].size); 368 #else 369 /* fp registers not used by kernel, leave zero */ 370 return 0; 371 #endif 372 } 373 374 return 0; 375 } 376 377 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 378 { 379 regs->nip = pc; 380 } 381 382 /* 383 * This function does PowerPC specific procesing for interfacing to gdb. 384 */ 385 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 386 char *remcom_in_buffer, char *remcom_out_buffer, 387 struct pt_regs *linux_regs) 388 { 389 char *ptr = &remcom_in_buffer[1]; 390 unsigned long addr; 391 392 switch (remcom_in_buffer[0]) { 393 /* 394 * sAA..AA Step one instruction from AA..AA 395 * This will return an error to gdb .. 396 */ 397 case 's': 398 case 'c': 399 /* handle the optional parameter */ 400 if (kgdb_hex2long(&ptr, &addr)) 401 linux_regs->nip = addr; 402 403 atomic_set(&kgdb_cpu_doing_single_step, -1); 404 /* set the trace bit if we're stepping */ 405 if (remcom_in_buffer[0] == 's') { 406 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 407 mtspr(SPRN_DBCR0, 408 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 409 linux_regs->msr |= MSR_DE; 410 #else 411 linux_regs->msr |= MSR_SE; 412 #endif 413 kgdb_single_step = 1; 414 atomic_set(&kgdb_cpu_doing_single_step, 415 raw_smp_processor_id()); 416 } 417 return 0; 418 } 419 420 return -1; 421 } 422 423 /* 424 * Global data 425 */ 426 struct kgdb_arch arch_kgdb_ops = { 427 .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08}, 428 }; 429 430 static int kgdb_not_implemented(struct pt_regs *regs) 431 { 432 return 0; 433 } 434 435 static void *old__debugger_ipi; 436 static void *old__debugger; 437 static void *old__debugger_bpt; 438 static void *old__debugger_sstep; 439 static void *old__debugger_iabr_match; 440 static void *old__debugger_dabr_match; 441 static void *old__debugger_fault_handler; 442 443 int kgdb_arch_init(void) 444 { 445 old__debugger_ipi = __debugger_ipi; 446 old__debugger = __debugger; 447 old__debugger_bpt = __debugger_bpt; 448 old__debugger_sstep = __debugger_sstep; 449 old__debugger_iabr_match = __debugger_iabr_match; 450 old__debugger_dabr_match = __debugger_dabr_match; 451 old__debugger_fault_handler = __debugger_fault_handler; 452 453 __debugger_ipi = kgdb_call_nmi_hook; 454 __debugger = kgdb_debugger; 455 __debugger_bpt = kgdb_handle_breakpoint; 456 __debugger_sstep = kgdb_singlestep; 457 __debugger_iabr_match = kgdb_iabr_match; 458 __debugger_dabr_match = kgdb_dabr_match; 459 __debugger_fault_handler = kgdb_not_implemented; 460 461 return 0; 462 } 463 464 void kgdb_arch_exit(void) 465 { 466 __debugger_ipi = old__debugger_ipi; 467 __debugger = old__debugger; 468 __debugger_bpt = old__debugger_bpt; 469 __debugger_sstep = old__debugger_sstep; 470 __debugger_iabr_match = old__debugger_iabr_match; 471 __debugger_dabr_match = old__debugger_dabr_match; 472 __debugger_fault_handler = old__debugger_fault_handler; 473 } 474