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) 196 197 198 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) 199 { 200 unsigned long *ptr = gdb_regs; 201 int reg; 202 203 memset(gdb_regs, 0, NUMREGBYTES); 204 205 for (reg = 0; reg < 32; reg++) 206 PACK64(ptr, regs->gpr[reg]); 207 208 #ifdef CONFIG_FSL_BOOKE 209 #ifdef CONFIG_SPE 210 for (reg = 0; reg < 32; reg++) 211 PACK64(ptr, current->thread.evr[reg]); 212 #else 213 ptr += 32; 214 #endif 215 #else 216 /* fp registers not used by kernel, leave zero */ 217 ptr += 32 * 8 / sizeof(long); 218 #endif 219 220 PACK64(ptr, regs->nip); 221 PACK64(ptr, regs->msr); 222 PACK32(ptr, regs->ccr); 223 PACK64(ptr, regs->link); 224 PACK64(ptr, regs->ctr); 225 PACK32(ptr, regs->xer); 226 227 BUG_ON((unsigned long)ptr > 228 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 229 } 230 231 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 232 { 233 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + 234 STACK_FRAME_OVERHEAD); 235 unsigned long *ptr = gdb_regs; 236 int reg; 237 238 memset(gdb_regs, 0, NUMREGBYTES); 239 240 /* Regs GPR0-2 */ 241 for (reg = 0; reg < 3; reg++) 242 PACK64(ptr, regs->gpr[reg]); 243 244 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ 245 ptr += 11; 246 247 /* Regs GPR14-31 */ 248 for (reg = 14; reg < 32; reg++) 249 PACK64(ptr, regs->gpr[reg]); 250 251 #ifdef CONFIG_FSL_BOOKE 252 #ifdef CONFIG_SPE 253 for (reg = 0; reg < 32; reg++) 254 PACK64(ptr, p->thread.evr[reg]); 255 #else 256 ptr += 32; 257 #endif 258 #else 259 /* fp registers not used by kernel, leave zero */ 260 ptr += 32 * 8 / sizeof(long); 261 #endif 262 263 PACK64(ptr, regs->nip); 264 PACK64(ptr, regs->msr); 265 PACK32(ptr, regs->ccr); 266 PACK64(ptr, regs->link); 267 PACK64(ptr, regs->ctr); 268 PACK32(ptr, regs->xer); 269 270 BUG_ON((unsigned long)ptr > 271 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 272 } 273 274 #define UNPACK64(dest, ptr) do { dest = *(ptr++); } while (0) 275 276 #define UNPACK32(dest, ptr) do { \ 277 u32 *ptr32; \ 278 ptr32 = (u32 *)ptr; \ 279 dest = *(ptr32++); \ 280 ptr = (unsigned long *)ptr32; \ 281 } while (0) 282 283 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) 284 { 285 unsigned long *ptr = gdb_regs; 286 int reg; 287 288 for (reg = 0; reg < 32; reg++) 289 UNPACK64(regs->gpr[reg], ptr); 290 291 #ifdef CONFIG_FSL_BOOKE 292 #ifdef CONFIG_SPE 293 for (reg = 0; reg < 32; reg++) 294 UNPACK64(current->thread.evr[reg], ptr); 295 #else 296 ptr += 32; 297 #endif 298 #else 299 /* fp registers not used by kernel, leave zero */ 300 ptr += 32 * 8 / sizeof(int); 301 #endif 302 303 UNPACK64(regs->nip, ptr); 304 UNPACK64(regs->msr, ptr); 305 UNPACK32(regs->ccr, ptr); 306 UNPACK64(regs->link, ptr); 307 UNPACK64(regs->ctr, ptr); 308 UNPACK32(regs->xer, ptr); 309 310 BUG_ON((unsigned long)ptr > 311 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); 312 } 313 314 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 315 { 316 regs->nip = pc; 317 } 318 319 /* 320 * This function does PowerPC specific procesing for interfacing to gdb. 321 */ 322 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 323 char *remcom_in_buffer, char *remcom_out_buffer, 324 struct pt_regs *linux_regs) 325 { 326 char *ptr = &remcom_in_buffer[1]; 327 unsigned long addr; 328 329 switch (remcom_in_buffer[0]) { 330 /* 331 * sAA..AA Step one instruction from AA..AA 332 * This will return an error to gdb .. 333 */ 334 case 's': 335 case 'c': 336 /* handle the optional parameter */ 337 if (kgdb_hex2long(&ptr, &addr)) 338 linux_regs->nip = addr; 339 340 atomic_set(&kgdb_cpu_doing_single_step, -1); 341 /* set the trace bit if we're stepping */ 342 if (remcom_in_buffer[0] == 's') { 343 #ifdef CONFIG_PPC_ADV_DEBUG_REGS 344 mtspr(SPRN_DBCR0, 345 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); 346 linux_regs->msr |= MSR_DE; 347 #else 348 linux_regs->msr |= MSR_SE; 349 #endif 350 kgdb_single_step = 1; 351 atomic_set(&kgdb_cpu_doing_single_step, 352 raw_smp_processor_id()); 353 } 354 return 0; 355 } 356 357 return -1; 358 } 359 360 /* 361 * Global data 362 */ 363 struct kgdb_arch arch_kgdb_ops = { 364 .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08}, 365 }; 366 367 static int kgdb_not_implemented(struct pt_regs *regs) 368 { 369 return 0; 370 } 371 372 static void *old__debugger_ipi; 373 static void *old__debugger; 374 static void *old__debugger_bpt; 375 static void *old__debugger_sstep; 376 static void *old__debugger_iabr_match; 377 static void *old__debugger_dabr_match; 378 static void *old__debugger_fault_handler; 379 380 int kgdb_arch_init(void) 381 { 382 old__debugger_ipi = __debugger_ipi; 383 old__debugger = __debugger; 384 old__debugger_bpt = __debugger_bpt; 385 old__debugger_sstep = __debugger_sstep; 386 old__debugger_iabr_match = __debugger_iabr_match; 387 old__debugger_dabr_match = __debugger_dabr_match; 388 old__debugger_fault_handler = __debugger_fault_handler; 389 390 __debugger_ipi = kgdb_call_nmi_hook; 391 __debugger = kgdb_debugger; 392 __debugger_bpt = kgdb_handle_breakpoint; 393 __debugger_sstep = kgdb_singlestep; 394 __debugger_iabr_match = kgdb_iabr_match; 395 __debugger_dabr_match = kgdb_dabr_match; 396 __debugger_fault_handler = kgdb_not_implemented; 397 398 return 0; 399 } 400 401 void kgdb_arch_exit(void) 402 { 403 __debugger_ipi = old__debugger_ipi; 404 __debugger = old__debugger; 405 __debugger_bpt = old__debugger_bpt; 406 __debugger_sstep = old__debugger_sstep; 407 __debugger_iabr_match = old__debugger_iabr_match; 408 __debugger_dabr_match = old__debugger_dabr_match; 409 __debugger_fault_handler = old__debugger_fault_handler; 410 } 411