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 #include <asm/irq_regs.h> 37 38 static struct hard_trap_info { 39 unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */ 40 unsigned char signo; /* Signal that we map this trap into */ 41 } hard_trap_info[] = { 42 { 6, SIGBUS }, /* instruction bus error */ 43 { 7, SIGBUS }, /* data bus error */ 44 { 9, SIGTRAP }, /* break */ 45 /* { 11, SIGILL }, */ /* CPU unusable */ 46 { 12, SIGFPE }, /* overflow */ 47 { 13, SIGTRAP }, /* trap */ 48 { 14, SIGSEGV }, /* virtual instruction cache coherency */ 49 { 15, SIGFPE }, /* floating point exception */ 50 { 23, SIGSEGV }, /* watch */ 51 { 31, SIGSEGV }, /* virtual data cache coherency */ 52 { 0, 0} /* Must be last */ 53 }; 54 55 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 56 { 57 { "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) }, 58 { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) }, 59 { "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) }, 60 { "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) }, 61 { "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) }, 62 { "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) }, 63 { "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) }, 64 { "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) }, 65 { "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) }, 66 { "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) }, 67 { "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) }, 68 { "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) }, 69 { "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) }, 70 { "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) }, 71 { "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) }, 72 { "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) }, 73 { "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) }, 74 { "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) }, 75 { "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) }, 76 { "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) }, 77 { "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) }, 78 { "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) }, 79 { "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) }, 80 { "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) }, 81 { "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) }, 82 { "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) }, 83 { "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) }, 84 { "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) }, 85 { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) }, 86 { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) }, 87 { "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) }, 88 { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) }, 89 { "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) }, 90 { "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) }, 91 { "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) }, 92 { "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) }, 93 { "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) }, 94 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) }, 95 { "f0", GDB_SIZEOF_REG, 0 }, 96 { "f1", GDB_SIZEOF_REG, 1 }, 97 { "f2", GDB_SIZEOF_REG, 2 }, 98 { "f3", GDB_SIZEOF_REG, 3 }, 99 { "f4", GDB_SIZEOF_REG, 4 }, 100 { "f5", GDB_SIZEOF_REG, 5 }, 101 { "f6", GDB_SIZEOF_REG, 6 }, 102 { "f7", GDB_SIZEOF_REG, 7 }, 103 { "f8", GDB_SIZEOF_REG, 8 }, 104 { "f9", GDB_SIZEOF_REG, 9 }, 105 { "f10", GDB_SIZEOF_REG, 10 }, 106 { "f11", GDB_SIZEOF_REG, 11 }, 107 { "f12", GDB_SIZEOF_REG, 12 }, 108 { "f13", GDB_SIZEOF_REG, 13 }, 109 { "f14", GDB_SIZEOF_REG, 14 }, 110 { "f15", GDB_SIZEOF_REG, 15 }, 111 { "f16", GDB_SIZEOF_REG, 16 }, 112 { "f17", GDB_SIZEOF_REG, 17 }, 113 { "f18", GDB_SIZEOF_REG, 18 }, 114 { "f19", GDB_SIZEOF_REG, 19 }, 115 { "f20", GDB_SIZEOF_REG, 20 }, 116 { "f21", GDB_SIZEOF_REG, 21 }, 117 { "f22", GDB_SIZEOF_REG, 22 }, 118 { "f23", GDB_SIZEOF_REG, 23 }, 119 { "f24", GDB_SIZEOF_REG, 24 }, 120 { "f25", GDB_SIZEOF_REG, 25 }, 121 { "f26", GDB_SIZEOF_REG, 26 }, 122 { "f27", GDB_SIZEOF_REG, 27 }, 123 { "f28", GDB_SIZEOF_REG, 28 }, 124 { "f29", GDB_SIZEOF_REG, 29 }, 125 { "f30", GDB_SIZEOF_REG, 30 }, 126 { "f31", GDB_SIZEOF_REG, 31 }, 127 { "fsr", GDB_SIZEOF_REG, 0 }, 128 { "fir", GDB_SIZEOF_REG, 0 }, 129 }; 130 131 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 132 { 133 int fp_reg; 134 135 if (regno < 0 || regno >= DBG_MAX_REG_NUM) 136 return -EINVAL; 137 138 if (dbg_reg_def[regno].offset != -1 && regno < 38) { 139 memcpy((void *)regs + dbg_reg_def[regno].offset, mem, 140 dbg_reg_def[regno].size); 141 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) { 142 /* FP registers 38 -> 69 */ 143 if (!(regs->cp0_status & ST0_CU1)) 144 return 0; 145 if (regno == 70) { 146 /* Process the fcr31/fsr (register 70) */ 147 memcpy((void *)¤t->thread.fpu.fcr31, mem, 148 dbg_reg_def[regno].size); 149 goto out_save; 150 } else if (regno == 71) { 151 /* Ignore the fir (register 71) */ 152 goto out_save; 153 } 154 fp_reg = dbg_reg_def[regno].offset; 155 memcpy((void *)¤t->thread.fpu.fpr[fp_reg], mem, 156 dbg_reg_def[regno].size); 157 out_save: 158 restore_fp(current); 159 } 160 161 return 0; 162 } 163 164 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 165 { 166 int fp_reg; 167 168 if (regno >= DBG_MAX_REG_NUM || regno < 0) 169 return NULL; 170 171 if (dbg_reg_def[regno].offset != -1 && regno < 38) { 172 /* First 38 registers */ 173 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, 174 dbg_reg_def[regno].size); 175 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) { 176 /* FP registers 38 -> 69 */ 177 if (!(regs->cp0_status & ST0_CU1)) 178 goto out; 179 save_fp(current); 180 if (regno == 70) { 181 /* Process the fcr31/fsr (register 70) */ 182 memcpy(mem, (void *)¤t->thread.fpu.fcr31, 183 dbg_reg_def[regno].size); 184 goto out; 185 } else if (regno == 71) { 186 /* Ignore the fir (register 71) */ 187 memset(mem, 0, dbg_reg_def[regno].size); 188 goto out; 189 } 190 fp_reg = dbg_reg_def[regno].offset; 191 memcpy(mem, (void *)¤t->thread.fpu.fpr[fp_reg], 192 dbg_reg_def[regno].size); 193 } 194 195 out: 196 return dbg_reg_def[regno].name; 197 198 } 199 200 void arch_kgdb_breakpoint(void) 201 { 202 __asm__ __volatile__( 203 ".globl breakinst\n\t" 204 ".set\tnoreorder\n\t" 205 "nop\n" 206 "breakinst:\tbreak\n\t" 207 "nop\n\t" 208 ".set\treorder"); 209 } 210 211 void kgdb_call_nmi_hook(void *ignored) 212 { 213 mm_segment_t old_fs; 214 215 old_fs = get_fs(); 216 set_fs(KERNEL_DS); 217 218 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); 219 220 set_fs(old_fs); 221 } 222 223 static int compute_signal(int tt) 224 { 225 struct hard_trap_info *ht; 226 227 for (ht = hard_trap_info; ht->tt && ht->signo; ht++) 228 if (ht->tt == tt) 229 return ht->signo; 230 231 return SIGHUP; /* default for things we don't know about */ 232 } 233 234 /* 235 * Similar to regs_to_gdb_regs() except that process is sleeping and so 236 * we may not be able to get all the info. 237 */ 238 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) 239 { 240 int reg; 241 #if (KGDB_GDB_REG_SIZE == 32) 242 u32 *ptr = (u32 *)gdb_regs; 243 #else 244 u64 *ptr = (u64 *)gdb_regs; 245 #endif 246 247 for (reg = 0; reg < 16; reg++) 248 *(ptr++) = 0; 249 250 /* S0 - S7 */ 251 *(ptr++) = p->thread.reg16; 252 *(ptr++) = p->thread.reg17; 253 *(ptr++) = p->thread.reg18; 254 *(ptr++) = p->thread.reg19; 255 *(ptr++) = p->thread.reg20; 256 *(ptr++) = p->thread.reg21; 257 *(ptr++) = p->thread.reg22; 258 *(ptr++) = p->thread.reg23; 259 260 for (reg = 24; reg < 28; reg++) 261 *(ptr++) = 0; 262 263 /* GP, SP, FP, RA */ 264 *(ptr++) = (long)p; 265 *(ptr++) = p->thread.reg29; 266 *(ptr++) = p->thread.reg30; 267 *(ptr++) = p->thread.reg31; 268 269 *(ptr++) = p->thread.cp0_status; 270 271 /* lo, hi */ 272 *(ptr++) = 0; 273 *(ptr++) = 0; 274 275 /* 276 * BadVAddr, Cause 277 * Ideally these would come from the last exception frame up the stack 278 * but that requires unwinding, otherwise we can't know much for sure. 279 */ 280 *(ptr++) = 0; 281 *(ptr++) = 0; 282 283 /* 284 * PC 285 * use return address (RA), i.e. the moment after return from resume() 286 */ 287 *(ptr++) = p->thread.reg31; 288 } 289 290 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 291 { 292 regs->cp0_epc = pc; 293 } 294 295 /* 296 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled, 297 * then try to fall into the debugger 298 */ 299 static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd, 300 void *ptr) 301 { 302 struct die_args *args = (struct die_args *)ptr; 303 struct pt_regs *regs = args->regs; 304 int trap = (regs->cp0_cause & 0x7c) >> 2; 305 mm_segment_t old_fs; 306 307 #ifdef CONFIG_KPROBES 308 /* 309 * Return immediately if the kprobes fault notifier has set 310 * DIE_PAGE_FAULT. 311 */ 312 if (cmd == DIE_PAGE_FAULT) 313 return NOTIFY_DONE; 314 #endif /* CONFIG_KPROBES */ 315 316 /* Userspace events, ignore. */ 317 if (user_mode(regs)) 318 return NOTIFY_DONE; 319 320 /* Kernel mode. Set correct address limit */ 321 old_fs = get_fs(); 322 set_fs(KERNEL_DS); 323 324 if (atomic_read(&kgdb_active) != -1) 325 kgdb_nmicallback(smp_processor_id(), regs); 326 327 if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs)) { 328 set_fs(old_fs); 329 return NOTIFY_DONE; 330 } 331 332 if (atomic_read(&kgdb_setting_breakpoint)) 333 if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst)) 334 regs->cp0_epc += 4; 335 336 /* In SMP mode, __flush_cache_all does IPI */ 337 local_irq_enable(); 338 __flush_cache_all(); 339 340 set_fs(old_fs); 341 return NOTIFY_STOP; 342 } 343 344 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP 345 int kgdb_ll_trap(int cmd, const char *str, 346 struct pt_regs *regs, long err, int trap, int sig) 347 { 348 struct die_args args = { 349 .regs = regs, 350 .str = str, 351 .err = err, 352 .trapnr = trap, 353 .signr = sig, 354 355 }; 356 357 if (!kgdb_io_module_registered) 358 return NOTIFY_DONE; 359 360 return kgdb_mips_notify(NULL, cmd, &args); 361 } 362 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */ 363 364 static struct notifier_block kgdb_notifier = { 365 .notifier_call = kgdb_mips_notify, 366 }; 367 368 /* 369 * Handle the 'c' command 370 */ 371 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 372 char *remcom_in_buffer, char *remcom_out_buffer, 373 struct pt_regs *regs) 374 { 375 char *ptr; 376 unsigned long address; 377 378 switch (remcom_in_buffer[0]) { 379 case 'c': 380 /* handle the optional parameter */ 381 ptr = &remcom_in_buffer[1]; 382 if (kgdb_hex2long(&ptr, &address)) 383 regs->cp0_epc = address; 384 385 return 0; 386 } 387 388 return -1; 389 } 390 391 const struct kgdb_arch arch_kgdb_ops = { 392 #ifdef CONFIG_CPU_BIG_ENDIAN 393 .gdb_bpt_instr = { spec_op << 2, 0x00, 0x00, break_op }, 394 #else 395 .gdb_bpt_instr = { break_op, 0x00, 0x00, spec_op << 2 }, 396 #endif 397 }; 398 399 int kgdb_arch_init(void) 400 { 401 register_die_notifier(&kgdb_notifier); 402 403 return 0; 404 } 405 406 /* 407 * kgdb_arch_exit - Perform any architecture specific uninitalization. 408 * 409 * This function will handle the uninitalization of any architecture 410 * specific callbacks, for dynamic registration and unregistration. 411 */ 412 void kgdb_arch_exit(void) 413 { 414 unregister_die_notifier(&kgdb_notifier); 415 } 416