1 /* 2 * Originally written by Glenn Engel, Lake Stevens Instrument Division 3 * 4 * Contributed by HP Systems 5 * 6 * Modified for Linux/MIPS (and MIPS in general) by Andreas Busse 7 * Send complaints, suggestions etc. to <andy@waldorf-gmbh.de> 8 * 9 * Copyright (C) 1995 Andreas Busse 10 * 11 * Copyright (C) 2003 MontaVista Software Inc. 12 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net 13 * 14 * Copyright (C) 2004-2005 MontaVista Software Inc. 15 * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com 16 * 17 * Copyright (C) 2007-2008 Wind River Systems, Inc. 18 * Author/Maintainer: Jason Wessel, jason.wessel@windriver.com 19 * 20 * This file is licensed under the terms of the GNU General Public License 21 * version 2. This program is licensed "as is" without any warranty of any 22 * kind, whether express or implied. 23 */ 24 25 #include <linux/ptrace.h> /* for linux pt_regs struct */ 26 #include <linux/kgdb.h> 27 #include <linux/kdebug.h> 28 #include <linux/sched.h> 29 #include <linux/smp.h> 30 #include <asm/inst.h> 31 #include <asm/fpu.h> 32 #include <asm/cacheflush.h> 33 #include <asm/processor.h> 34 #include <asm/sigcontext.h> 35 #include <linux/uaccess.h> 36 37 static struct hard_trap_info { 38 unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */ 39 unsigned char signo; /* Signal that we map this trap into */ 40 } hard_trap_info[] = { 41 { 6, SIGBUS }, /* instruction bus error */ 42 { 7, SIGBUS }, /* data bus error */ 43 { 9, SIGTRAP }, /* break */ 44 /* { 11, SIGILL }, */ /* CPU unusable */ 45 { 12, SIGFPE }, /* overflow */ 46 { 13, SIGTRAP }, /* trap */ 47 { 14, SIGSEGV }, /* virtual instruction cache coherency */ 48 { 15, SIGFPE }, /* floating point exception */ 49 { 23, SIGSEGV }, /* watch */ 50 { 31, SIGSEGV }, /* virtual data cache coherency */ 51 { 0, 0} /* Must be last */ 52 }; 53 54 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 55 { 56 { "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) }, 57 { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) }, 58 { "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) }, 59 { "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) }, 60 { "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) }, 61 { "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) }, 62 { "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) }, 63 { "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) }, 64 { "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) }, 65 { "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) }, 66 { "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) }, 67 { "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) }, 68 { "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) }, 69 { "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) }, 70 { "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) }, 71 { "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) }, 72 { "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) }, 73 { "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) }, 74 { "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) }, 75 { "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) }, 76 { "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) }, 77 { "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) }, 78 { "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) }, 79 { "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) }, 80 { "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) }, 81 { "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) }, 82 { "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) }, 83 { "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) }, 84 { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) }, 85 { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) }, 86 { "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) }, 87 { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) }, 88 { "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) }, 89 { "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) }, 90 { "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) }, 91 { "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) }, 92 { "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) }, 93 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) }, 94 { "f0", GDB_SIZEOF_REG, 0 }, 95 { "f1", GDB_SIZEOF_REG, 1 }, 96 { "f2", GDB_SIZEOF_REG, 2 }, 97 { "f3", GDB_SIZEOF_REG, 3 }, 98 { "f4", GDB_SIZEOF_REG, 4 }, 99 { "f5", GDB_SIZEOF_REG, 5 }, 100 { "f6", GDB_SIZEOF_REG, 6 }, 101 { "f7", GDB_SIZEOF_REG, 7 }, 102 { "f8", GDB_SIZEOF_REG, 8 }, 103 { "f9", GDB_SIZEOF_REG, 9 }, 104 { "f10", GDB_SIZEOF_REG, 10 }, 105 { "f11", GDB_SIZEOF_REG, 11 }, 106 { "f12", GDB_SIZEOF_REG, 12 }, 107 { "f13", GDB_SIZEOF_REG, 13 }, 108 { "f14", GDB_SIZEOF_REG, 14 }, 109 { "f15", GDB_SIZEOF_REG, 15 }, 110 { "f16", GDB_SIZEOF_REG, 16 }, 111 { "f17", GDB_SIZEOF_REG, 17 }, 112 { "f18", GDB_SIZEOF_REG, 18 }, 113 { "f19", GDB_SIZEOF_REG, 19 }, 114 { "f20", GDB_SIZEOF_REG, 20 }, 115 { "f21", GDB_SIZEOF_REG, 21 }, 116 { "f22", GDB_SIZEOF_REG, 22 }, 117 { "f23", GDB_SIZEOF_REG, 23 }, 118 { "f24", GDB_SIZEOF_REG, 24 }, 119 { "f25", GDB_SIZEOF_REG, 25 }, 120 { "f26", GDB_SIZEOF_REG, 26 }, 121 { "f27", GDB_SIZEOF_REG, 27 }, 122 { "f28", GDB_SIZEOF_REG, 28 }, 123 { "f29", GDB_SIZEOF_REG, 29 }, 124 { "f30", GDB_SIZEOF_REG, 30 }, 125 { "f31", GDB_SIZEOF_REG, 31 }, 126 { "fsr", GDB_SIZEOF_REG, 0 }, 127 { "fir", GDB_SIZEOF_REG, 0 }, 128 }; 129 130 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 131 { 132 int fp_reg; 133 134 if (regno < 0 || regno >= DBG_MAX_REG_NUM) 135 return -EINVAL; 136 137 if (dbg_reg_def[regno].offset != -1 && regno < 38) { 138 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 139 dbg_reg_def[regno].size); 140 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) { 141 /* FP registers 38 -> 69 */ 142 if (!(regs->cp0_status & ST0_CU1)) 143 return 0; 144 if (regno == 70) { 145 /* Process the fcr31/fsr (register 70) */ 146 memcpy((void *)¤t->thread.fpu.fcr31, mem, 147 dbg_reg_def[regno].size); 148 goto out_save; 149 } else if (regno == 71) { 150 /* Ignore the fir (register 71) */ 151 goto out_save; 152 } 153 fp_reg = dbg_reg_def[regno].offset; 154 memcpy((void *)¤t->thread.fpu.fpr[fp_reg], mem, 155 dbg_reg_def[regno].size); 156 out_save: 157 restore_fp(current); 158 } 159 160 return 0; 161 } 162 163 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 164 { 165 int fp_reg; 166 167 if (regno >= DBG_MAX_REG_NUM || regno < 0) 168 return NULL; 169 170 if (dbg_reg_def[regno].offset != -1 && regno < 38) { 171 /* First 38 registers */ 172 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 173 dbg_reg_def[regno].size); 174 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) { 175 /* FP registers 38 -> 69 */ 176 if (!(regs->cp0_status & ST0_CU1)) 177 goto out; 178 save_fp(current); 179 if (regno == 70) { 180 /* Process the fcr31/fsr (register 70) */ 181 memcpy(mem, (void *)¤t->thread.fpu.fcr31, 182 dbg_reg_def[regno].size); 183 goto out; 184 } else if (regno == 71) { 185 /* Ignore the fir (register 71) */ 186 memset(mem, 0, dbg_reg_def[regno].size); 187 goto out; 188 } 189 fp_reg = dbg_reg_def[regno].offset; 190 memcpy(mem, (void *)¤t->thread.fpu.fpr[fp_reg], 191 dbg_reg_def[regno].size); 192 } 193 194 out: 195 return dbg_reg_def[regno].name; 196 197 } 198 199 void arch_kgdb_breakpoint(void) 200 { 201 __asm__ __volatile__( 202 ".globl breakinst\n\t" 203 ".set\tnoreorder\n\t" 204 "nop\n" 205 "breakinst:\tbreak\n\t" 206 "nop\n\t" 207 ".set\treorder"); 208 } 209 210 void kgdb_call_nmi_hook(void *ignored) 211 { 212 mm_segment_t old_fs; 213 214 old_fs = get_fs(); 215 set_fs(get_ds()); 216 217 kgdb_nmicallback(raw_smp_processor_id(), NULL); 218 219 set_fs(old_fs); 220 } 221 222 static int compute_signal(int tt) 223 { 224 struct hard_trap_info *ht; 225 226 for (ht = hard_trap_info; ht->tt && ht->signo; ht++) 227 if (ht->tt == tt) 228 return ht->signo; 229 230 return SIGHUP; /* default for things we don't know about */ 231 } 232 233 /* 234 * Similar to regs_to_gdb_regs() except that process is sleeping and so 235 * we may not be able to get all the info. 236 */ 237 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 238 { 239 int reg; 240 #if (KGDB_GDB_REG_SIZE == 32) 241 u32 *ptr = (u32 *)gdb_regs; 242 #else 243 u64 *ptr = (u64 *)gdb_regs; 244 #endif 245 246 for (reg = 0; reg < 16; reg++) 247 *(ptr++) = 0; 248 249 /* S0 - S7 */ 250 *(ptr++) = p->thread.reg16; 251 *(ptr++) = p->thread.reg17; 252 *(ptr++) = p->thread.reg18; 253 *(ptr++) = p->thread.reg19; 254 *(ptr++) = p->thread.reg20; 255 *(ptr++) = p->thread.reg21; 256 *(ptr++) = p->thread.reg22; 257 *(ptr++) = p->thread.reg23; 258 259 for (reg = 24; reg < 28; reg++) 260 *(ptr++) = 0; 261 262 /* GP, SP, FP, RA */ 263 *(ptr++) = (long)p; 264 *(ptr++) = p->thread.reg29; 265 *(ptr++) = p->thread.reg30; 266 *(ptr++) = p->thread.reg31; 267 268 *(ptr++) = p->thread.cp0_status; 269 270 /* lo, hi */ 271 *(ptr++) = 0; 272 *(ptr++) = 0; 273 274 /* 275 * BadVAddr, Cause 276 * Ideally these would come from the last exception frame up the stack 277 * but that requires unwinding, otherwise we can't know much for sure. 278 */ 279 *(ptr++) = 0; 280 *(ptr++) = 0; 281 282 /* 283 * PC 284 * use return address (RA), i.e. the moment after return from resume() 285 */ 286 *(ptr++) = p->thread.reg31; 287 } 288 289 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 290 { 291 regs->cp0_epc = pc; 292 } 293 294 /* 295 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled, 296 * then try to fall into the debugger 297 */ 298 static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd, 299 void *ptr) 300 { 301 struct die_args *args = (struct die_args *)ptr; 302 struct pt_regs *regs = args->regs; 303 int trap = (regs->cp0_cause & 0x7c) >> 2; 304 mm_segment_t old_fs; 305 306 #ifdef CONFIG_KPROBES 307 /* 308 * Return immediately if the kprobes fault notifier has set 309 * DIE_PAGE_FAULT. 310 */ 311 if (cmd == DIE_PAGE_FAULT) 312 return NOTIFY_DONE; 313 #endif /* CONFIG_KPROBES */ 314 315 /* Userspace events, ignore. */ 316 if (user_mode(regs)) 317 return NOTIFY_DONE; 318 319 /* Kernel mode. Set correct address limit */ 320 old_fs = get_fs(); 321 set_fs(get_ds()); 322 323 if (atomic_read(&kgdb_active) != -1) 324 kgdb_nmicallback(smp_processor_id(), regs); 325 326 if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs)) { 327 set_fs(old_fs); 328 return NOTIFY_DONE; 329 } 330 331 if (atomic_read(&kgdb_setting_breakpoint)) 332 if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst)) 333 regs->cp0_epc += 4; 334 335 /* In SMP mode, __flush_cache_all does IPI */ 336 local_irq_enable(); 337 __flush_cache_all(); 338 339 set_fs(old_fs); 340 return NOTIFY_STOP; 341 } 342 343 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP 344 int kgdb_ll_trap(int cmd, const char *str, 345 struct pt_regs *regs, long err, int trap, int sig) 346 { 347 struct die_args args = { 348 .regs = regs, 349 .str = str, 350 .err = err, 351 .trapnr = trap, 352 .signr = sig, 353 354 }; 355 356 if (!kgdb_io_module_registered) 357 return NOTIFY_DONE; 358 359 return kgdb_mips_notify(NULL, cmd, &args); 360 } 361 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */ 362 363 static struct notifier_block kgdb_notifier = { 364 .notifier_call = kgdb_mips_notify, 365 }; 366 367 /* 368 * Handle the 'c' command 369 */ 370 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 371 char *remcom_in_buffer, char *remcom_out_buffer, 372 struct pt_regs *regs) 373 { 374 char *ptr; 375 unsigned long address; 376 377 switch (remcom_in_buffer[0]) { 378 case 'c': 379 /* handle the optional parameter */ 380 ptr = &remcom_in_buffer[1]; 381 if (kgdb_hex2long(&ptr, &address)) 382 regs->cp0_epc = address; 383 384 return 0; 385 } 386 387 return -1; 388 } 389 390 const struct kgdb_arch arch_kgdb_ops = { 391 #ifdef CONFIG_CPU_BIG_ENDIAN 392 .gdb_bpt_instr = { spec_op << 2, 0x00, 0x00, break_op }, 393 #else 394 .gdb_bpt_instr = { break_op, 0x00, 0x00, spec_op << 2 }, 395 #endif 396 }; 397 398 int kgdb_arch_init(void) 399 { 400 register_die_notifier(&kgdb_notifier); 401 402 return 0; 403 } 404 405 /* 406 * kgdb_arch_exit - Perform any architecture specific uninitalization. 407 * 408 * This function will handle the uninitalization of any architecture 409 * specific callbacks, for dynamic registration and unregistration. 410 */ 411 void kgdb_arch_exit(void) 412 { 413 unregister_die_notifier(&kgdb_notifier); 414 } 415