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