1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * PowerPC backend to the KGDB stub. 4 * 5 * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu) 6 * Copyright (C) 2003 Timesys Corporation. 7 * Copyright (C) 2004-2006 MontaVista Software, Inc. 8 * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com) 9 * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and 10 * Sergei Shtylyov <sshtylyov@ru.mvista.com> 11 * Copyright (C) 2007-2008 Wind River Systems, Inc. 12 */ 13 14#include <linux/kernel.h> 15#include <linux/kgdb.h> 16#include <linux/smp.h> 17#include <linux/signal.h> 18#include <linux/ptrace.h> 19#include <linux/kdebug.h> 20#include <asm/current.h> 21#include <asm/processor.h> 22#include <asm/machdep.h> 23#include <asm/debug.h> 24#include <asm/code-patching.h> 25#include <linux/slab.h> 26#include <asm/inst.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 */ 33static 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#ifdef CONFIG_BOOKE_OR_40x 49 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */ 50#if defined(CONFIG_PPC_85xx) 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_PPC_85xx */ 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 /* !CONFIG_BOOKE_OR_40x */ 68 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */ 69#if defined(CONFIG_PPC_8xx) 70 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */ 71#else /* ! CONFIG_PPC_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 92static 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/** 104 * 105 * kgdb_skipexception - Bail out of KGDB when we've been triggered. 106 * @exception: Exception vector number 107 * @regs: Current &struct pt_regs. 108 * 109 * On some architectures we need to skip a breakpoint exception when 110 * it occurs after a breakpoint has been removed. 111 * 112 */ 113int kgdb_skipexception(int exception, struct pt_regs *regs) 114{ 115 return kgdb_isremovedbreak(regs->nip); 116} 117 118static int kgdb_debugger_ipi(struct pt_regs *regs) 119{ 120 kgdb_nmicallback(raw_smp_processor_id(), regs); 121 return 0; 122} 123 124#ifdef CONFIG_SMP 125void kgdb_roundup_cpus(void) 126{ 127 smp_send_debugger_break(); 128} 129#endif 130 131/* KGDB functions to use existing PowerPC64 hooks. */ 132static int kgdb_debugger(struct pt_regs *regs) 133{ 134 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), 135 DIE_OOPS, regs); 136} 137 138static int kgdb_handle_breakpoint(struct pt_regs *regs) 139{ 140 if (user_mode(regs)) 141 return 0; 142 143 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) 144 return 0; 145 146 if (*(u32 *)regs->nip == BREAK_INSTR) 147 regs_add_return_ip(regs, BREAK_INSTR_SIZE); 148 149 return 1; 150} 151 152static int kgdb_singlestep(struct pt_regs *regs) 153{ 154 if (user_mode(regs)) 155 return 0; 156 157 kgdb_handle_exception(0, SIGTRAP, 0, regs); 158 159 return 1; 160} 161 162static int kgdb_iabr_match(struct pt_regs *regs) 163{ 164 if (user_mode(regs)) 165 return 0; 166 167 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 168 return 0; 169 return 1; 170} 171 172static int kgdb_break_match(struct pt_regs *regs) 173{ 174 if (user_mode(regs)) 175 return 0; 176 177 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) 178 return 0; 179 return 1; 180} 181 182#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) 183 184#define PACK32(ptr, src) do { \ 185 u32 *ptr32; \ 186 ptr32 = (u32 *)ptr; \ 187 *(ptr32++) = (src); \ 188 ptr = (unsigned long *)ptr32; \ 189 } while (0) 190 191void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 192{ 193 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 194 STACK_INT_FRAME_REGS); 195 unsigned long *ptr = gdb_regs; 196 int reg; 197 198 memset(gdb_regs, 0, NUMREGBYTES); 199 200 /* Regs GPR0-2 */ 201 for (reg = 0; reg < 3; reg++) 202 PACK64(ptr, regs->gpr[reg]); 203 204 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 205 ptr += 11; 206 207 /* Regs GPR14-31 */ 208 for (reg = 14; reg < 32; reg++) 209 PACK64(ptr, regs->gpr[reg]); 210 211#ifdef CONFIG_PPC_85xx 212#ifdef CONFIG_SPE 213 for (reg = 0; reg < 32; reg++) 214 PACK64(ptr, p->thread.evr[reg]); 215#else 216 ptr += 32; 217#endif 218#else 219 /* fp registers not used by kernel, leave zero */ 220 ptr += 32 * 8 / sizeof(long); 221#endif 222 223 PACK64(ptr, regs->nip); 224 PACK64(ptr, regs->msr); 225 PACK32(ptr, regs->ccr); 226 PACK64(ptr, regs->link); 227 PACK64(ptr, regs->ctr); 228 PACK32(ptr, regs->xer); 229 230 BUG_ON((unsigned long)ptr > 231 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 232} 233 234#define GDB_SIZEOF_REG sizeof(unsigned long) 235#define GDB_SIZEOF_REG_U32 sizeof(u32) 236 237#ifdef CONFIG_PPC_85xx 238#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long) 239#else 240#define GDB_SIZEOF_FLOAT_REG sizeof(u64) 241#endif 242 243struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 244{ 245 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) }, 246 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) }, 247 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) }, 248 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) }, 249 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) }, 250 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) }, 251 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) }, 252 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) }, 253 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) }, 254 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) }, 255 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) }, 256 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) }, 257 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) }, 258 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) }, 259 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) }, 260 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) }, 261 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) }, 262 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) }, 263 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) }, 264 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) }, 265 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) }, 266 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) }, 267 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) }, 268 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) }, 269 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) }, 270 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) }, 271 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) }, 272 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) }, 273 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) }, 274 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) }, 275 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) }, 276 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) }, 277 278 { "f0", GDB_SIZEOF_FLOAT_REG, 0 }, 279 { "f1", GDB_SIZEOF_FLOAT_REG, 1 }, 280 { "f2", GDB_SIZEOF_FLOAT_REG, 2 }, 281 { "f3", GDB_SIZEOF_FLOAT_REG, 3 }, 282 { "f4", GDB_SIZEOF_FLOAT_REG, 4 }, 283 { "f5", GDB_SIZEOF_FLOAT_REG, 5 }, 284 { "f6", GDB_SIZEOF_FLOAT_REG, 6 }, 285 { "f7", GDB_SIZEOF_FLOAT_REG, 7 }, 286 { "f8", GDB_SIZEOF_FLOAT_REG, 8 }, 287 { "f9", GDB_SIZEOF_FLOAT_REG, 9 }, 288 { "f10", GDB_SIZEOF_FLOAT_REG, 10 }, 289 { "f11", GDB_SIZEOF_FLOAT_REG, 11 }, 290 { "f12", GDB_SIZEOF_FLOAT_REG, 12 }, 291 { "f13", GDB_SIZEOF_FLOAT_REG, 13 }, 292 { "f14", GDB_SIZEOF_FLOAT_REG, 14 }, 293 { "f15", GDB_SIZEOF_FLOAT_REG, 15 }, 294 { "f16", GDB_SIZEOF_FLOAT_REG, 16 }, 295 { "f17", GDB_SIZEOF_FLOAT_REG, 17 }, 296 { "f18", GDB_SIZEOF_FLOAT_REG, 18 }, 297 { "f19", GDB_SIZEOF_FLOAT_REG, 19 }, 298 { "f20", GDB_SIZEOF_FLOAT_REG, 20 }, 299 { "f21", GDB_SIZEOF_FLOAT_REG, 21 }, 300 { "f22", GDB_SIZEOF_FLOAT_REG, 22 }, 301 { "f23", GDB_SIZEOF_FLOAT_REG, 23 }, 302 { "f24", GDB_SIZEOF_FLOAT_REG, 24 }, 303 { "f25", GDB_SIZEOF_FLOAT_REG, 25 }, 304 { "f26", GDB_SIZEOF_FLOAT_REG, 26 }, 305 { "f27", GDB_SIZEOF_FLOAT_REG, 27 }, 306 { "f28", GDB_SIZEOF_FLOAT_REG, 28 }, 307 { "f29", GDB_SIZEOF_FLOAT_REG, 29 }, 308 { "f30", GDB_SIZEOF_FLOAT_REG, 30 }, 309 { "f31", GDB_SIZEOF_FLOAT_REG, 31 }, 310 311 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) }, 312 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) }, 313 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) }, 314 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) }, 315 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) }, 316 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) }, 317}; 318 319char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 320{ 321 if (regno >= DBG_MAX_REG_NUM || regno < 0) 322 return NULL; 323 324 if (regno < 32 || regno >= 64) 325 /* First 0 -> 31 gpr registers*/ 326 /* pc, msr, ls... registers 64 -> 69 */ 327 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 328 dbg_reg_def[regno].size); 329 330 if (regno >= 32 && regno < 64) { 331 /* FP registers 32 -> 63 */ 332#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE) 333 if (current) 334 memcpy(mem, ¤t->thread.evr[regno-32], 335 dbg_reg_def[regno].size); 336#else 337 /* fp registers not used by kernel, leave zero */ 338 memset(mem, 0, dbg_reg_def[regno].size); 339#endif 340 } 341 342 return dbg_reg_def[regno].name; 343} 344 345int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 346{ 347 if (regno >= DBG_MAX_REG_NUM || regno < 0) 348 return -EINVAL; 349 350 if (regno < 32 || regno >= 64) 351 /* First 0 -> 31 gpr registers*/ 352 /* pc, msr, ls... registers 64 -> 69 */ 353 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 354 dbg_reg_def[regno].size); 355 356 if (regno >= 32 && regno < 64) { 357 /* FP registers 32 -> 63 */ 358#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE) 359 memcpy(¤t->thread.evr[regno-32], mem, 360 dbg_reg_def[regno].size); 361#else 362 /* fp registers not used by kernel, leave zero */ 363 return 0; 364#endif 365 } 366 367 return 0; 368} 369 370void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 371{ 372 regs_set_return_ip(regs, pc); 373} 374 375/* 376 * This function does PowerPC specific processing for interfacing to gdb. 377 */ 378int kgdb_arch_handle_exception(int vector, int signo, int err_code, 379 char *remcom_in_buffer, char *remcom_out_buffer, 380 struct pt_regs *linux_regs) 381{ 382 char *ptr = &remcom_in_buffer[1]; 383 unsigned long addr; 384 385 switch (remcom_in_buffer[0]) { 386 /* 387 * sAA..AA Step one instruction from AA..AA 388 * This will return an error to gdb .. 389 */ 390 case 's': 391 case 'c': 392 /* handle the optional parameter */ 393 if (kgdb_hex2long(&ptr, &addr)) 394 regs_set_return_ip(linux_regs, addr); 395 396 atomic_set(&kgdb_cpu_doing_single_step, -1); 397 /* set the trace bit if we're stepping */ 398 if (remcom_in_buffer[0] == 's') { 399#ifdef CONFIG_PPC_ADV_DEBUG_REGS 400 mtspr(SPRN_DBCR0, 401 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 402 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE); 403#else 404 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE); 405#endif 406 atomic_set(&kgdb_cpu_doing_single_step, 407 raw_smp_processor_id()); 408 } 409 return 0; 410 } 411 412 return -1; 413} 414 415int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 416{ 417 u32 instr, *addr = (u32 *)bpt->bpt_addr; 418 int err; 419 420 err = get_kernel_nofault(instr, addr); 421 if (err) 422 return err; 423 424 err = patch_instruction(addr, ppc_inst(BREAK_INSTR)); 425 if (err) 426 return -EFAULT; 427 428 *(u32 *)bpt->saved_instr = instr; 429 430 return 0; 431} 432 433int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) 434{ 435 int err; 436 unsigned int instr = *(unsigned int *)bpt->saved_instr; 437 u32 *addr = (u32 *)bpt->bpt_addr; 438 439 err = patch_instruction(addr, ppc_inst(instr)); 440 if (err) 441 return -EFAULT; 442 443 return 0; 444} 445 446/* 447 * Global data 448 */ 449const struct kgdb_arch arch_kgdb_ops; 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_debugger_ipi; 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