1 /* 2 * Based on arch/arm/kernel/traps.c 3 * 4 * Copyright (C) 1995-2009 Russell King 5 * Copyright (C) 2012 ARM Ltd. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/signal.h> 21 #include <linux/personality.h> 22 #include <linux/kallsyms.h> 23 #include <linux/spinlock.h> 24 #include <linux/uaccess.h> 25 #include <linux/hardirq.h> 26 #include <linux/kdebug.h> 27 #include <linux/module.h> 28 #include <linux/kexec.h> 29 #include <linux/delay.h> 30 #include <linux/init.h> 31 #include <linux/sched.h> 32 #include <linux/syscalls.h> 33 34 #include <asm/atomic.h> 35 #include <asm/debug-monitors.h> 36 #include <asm/esr.h> 37 #include <asm/traps.h> 38 #include <asm/stacktrace.h> 39 #include <asm/exception.h> 40 #include <asm/system_misc.h> 41 42 static const char *handler[]= { 43 "Synchronous Abort", 44 "IRQ", 45 "FIQ", 46 "Error" 47 }; 48 49 int show_unhandled_signals = 1; 50 51 /* 52 * Dump out the contents of some memory nicely... 53 */ 54 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 55 unsigned long top) 56 { 57 unsigned long first; 58 mm_segment_t fs; 59 int i; 60 61 /* 62 * We need to switch to kernel mode so that we can use __get_user 63 * to safely read from kernel space. Note that we now dump the 64 * code first, just in case the backtrace kills us. 65 */ 66 fs = get_fs(); 67 set_fs(KERNEL_DS); 68 69 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); 70 71 for (first = bottom & ~31; first < top; first += 32) { 72 unsigned long p; 73 char str[sizeof(" 12345678") * 8 + 1]; 74 75 memset(str, ' ', sizeof(str)); 76 str[sizeof(str) - 1] = '\0'; 77 78 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 79 if (p >= bottom && p < top) { 80 unsigned int val; 81 if (__get_user(val, (unsigned int *)p) == 0) 82 sprintf(str + i * 9, " %08x", val); 83 else 84 sprintf(str + i * 9, " ????????"); 85 } 86 } 87 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 88 } 89 90 set_fs(fs); 91 } 92 93 static void dump_backtrace_entry(unsigned long where, unsigned long stack) 94 { 95 print_ip_sym(where); 96 if (in_exception_text(where)) 97 dump_mem("", "Exception stack", stack, 98 stack + sizeof(struct pt_regs)); 99 } 100 101 static void dump_instr(const char *lvl, struct pt_regs *regs) 102 { 103 unsigned long addr = instruction_pointer(regs); 104 mm_segment_t fs; 105 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 106 int i; 107 108 /* 109 * We need to switch to kernel mode so that we can use __get_user 110 * to safely read from kernel space. Note that we now dump the 111 * code first, just in case the backtrace kills us. 112 */ 113 fs = get_fs(); 114 set_fs(KERNEL_DS); 115 116 for (i = -4; i < 1; i++) { 117 unsigned int val, bad; 118 119 bad = __get_user(val, &((u32 *)addr)[i]); 120 121 if (!bad) 122 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); 123 else { 124 p += sprintf(p, "bad PC value"); 125 break; 126 } 127 } 128 printk("%sCode: %s\n", lvl, str); 129 130 set_fs(fs); 131 } 132 133 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 134 { 135 struct stackframe frame; 136 137 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); 138 139 if (!tsk) 140 tsk = current; 141 142 if (regs) { 143 frame.fp = regs->regs[29]; 144 frame.sp = regs->sp; 145 frame.pc = regs->pc; 146 } else if (tsk == current) { 147 frame.fp = (unsigned long)__builtin_frame_address(0); 148 frame.sp = current_stack_pointer; 149 frame.pc = (unsigned long)dump_backtrace; 150 } else { 151 /* 152 * task blocked in __switch_to 153 */ 154 frame.fp = thread_saved_fp(tsk); 155 frame.sp = thread_saved_sp(tsk); 156 frame.pc = thread_saved_pc(tsk); 157 } 158 159 pr_emerg("Call trace:\n"); 160 while (1) { 161 unsigned long where = frame.pc; 162 int ret; 163 164 ret = unwind_frame(&frame); 165 if (ret < 0) 166 break; 167 dump_backtrace_entry(where, frame.sp); 168 } 169 } 170 171 void show_stack(struct task_struct *tsk, unsigned long *sp) 172 { 173 dump_backtrace(NULL, tsk); 174 barrier(); 175 } 176 177 #ifdef CONFIG_PREEMPT 178 #define S_PREEMPT " PREEMPT" 179 #else 180 #define S_PREEMPT "" 181 #endif 182 #ifdef CONFIG_SMP 183 #define S_SMP " SMP" 184 #else 185 #define S_SMP "" 186 #endif 187 188 static int __die(const char *str, int err, struct thread_info *thread, 189 struct pt_regs *regs) 190 { 191 struct task_struct *tsk = thread->task; 192 static int die_counter; 193 int ret; 194 195 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", 196 str, err, ++die_counter); 197 198 /* trap and error numbers are mostly meaningless on ARM */ 199 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV); 200 if (ret == NOTIFY_STOP) 201 return ret; 202 203 print_modules(); 204 __show_regs(regs); 205 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 206 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); 207 208 if (!user_mode(regs) || in_interrupt()) { 209 dump_mem(KERN_EMERG, "Stack: ", regs->sp, 210 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 211 dump_backtrace(regs, tsk); 212 dump_instr(KERN_EMERG, regs); 213 } 214 215 return ret; 216 } 217 218 static DEFINE_RAW_SPINLOCK(die_lock); 219 220 /* 221 * This function is protected against re-entrancy. 222 */ 223 void die(const char *str, struct pt_regs *regs, int err) 224 { 225 struct thread_info *thread = current_thread_info(); 226 int ret; 227 228 oops_enter(); 229 230 raw_spin_lock_irq(&die_lock); 231 console_verbose(); 232 bust_spinlocks(1); 233 ret = __die(str, err, thread, regs); 234 235 if (regs && kexec_should_crash(thread->task)) 236 crash_kexec(regs); 237 238 bust_spinlocks(0); 239 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 240 raw_spin_unlock_irq(&die_lock); 241 oops_exit(); 242 243 if (in_interrupt()) 244 panic("Fatal exception in interrupt"); 245 if (panic_on_oops) 246 panic("Fatal exception"); 247 if (ret != NOTIFY_STOP) 248 do_exit(SIGSEGV); 249 } 250 251 void arm64_notify_die(const char *str, struct pt_regs *regs, 252 struct siginfo *info, int err) 253 { 254 if (user_mode(regs)) { 255 current->thread.fault_address = 0; 256 current->thread.fault_code = err; 257 force_sig_info(info->si_signo, info, current); 258 } else { 259 die(str, regs, err); 260 } 261 } 262 263 static LIST_HEAD(undef_hook); 264 static DEFINE_RAW_SPINLOCK(undef_lock); 265 266 void register_undef_hook(struct undef_hook *hook) 267 { 268 unsigned long flags; 269 270 raw_spin_lock_irqsave(&undef_lock, flags); 271 list_add(&hook->node, &undef_hook); 272 raw_spin_unlock_irqrestore(&undef_lock, flags); 273 } 274 275 void unregister_undef_hook(struct undef_hook *hook) 276 { 277 unsigned long flags; 278 279 raw_spin_lock_irqsave(&undef_lock, flags); 280 list_del(&hook->node); 281 raw_spin_unlock_irqrestore(&undef_lock, flags); 282 } 283 284 static int call_undef_hook(struct pt_regs *regs) 285 { 286 struct undef_hook *hook; 287 unsigned long flags; 288 u32 instr; 289 int (*fn)(struct pt_regs *regs, u32 instr) = NULL; 290 void __user *pc = (void __user *)instruction_pointer(regs); 291 292 if (!user_mode(regs)) 293 return 1; 294 295 if (compat_thumb_mode(regs)) { 296 /* 16-bit Thumb instruction */ 297 if (get_user(instr, (u16 __user *)pc)) 298 goto exit; 299 instr = le16_to_cpu(instr); 300 if (aarch32_insn_is_wide(instr)) { 301 u32 instr2; 302 303 if (get_user(instr2, (u16 __user *)(pc + 2))) 304 goto exit; 305 instr2 = le16_to_cpu(instr2); 306 instr = (instr << 16) | instr2; 307 } 308 } else { 309 /* 32-bit ARM instruction */ 310 if (get_user(instr, (u32 __user *)pc)) 311 goto exit; 312 instr = le32_to_cpu(instr); 313 } 314 315 raw_spin_lock_irqsave(&undef_lock, flags); 316 list_for_each_entry(hook, &undef_hook, node) 317 if ((instr & hook->instr_mask) == hook->instr_val && 318 (regs->pstate & hook->pstate_mask) == hook->pstate_val) 319 fn = hook->fn; 320 321 raw_spin_unlock_irqrestore(&undef_lock, flags); 322 exit: 323 return fn ? fn(regs, instr) : 1; 324 } 325 326 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 327 { 328 siginfo_t info; 329 void __user *pc = (void __user *)instruction_pointer(regs); 330 331 /* check for AArch32 breakpoint instructions */ 332 if (!aarch32_break_handler(regs)) 333 return; 334 335 if (call_undef_hook(regs) == 0) 336 return; 337 338 if (show_unhandled_signals && unhandled_signal(current, SIGILL) && 339 printk_ratelimit()) { 340 pr_info("%s[%d]: undefined instruction: pc=%p\n", 341 current->comm, task_pid_nr(current), pc); 342 dump_instr(KERN_INFO, regs); 343 } 344 345 info.si_signo = SIGILL; 346 info.si_errno = 0; 347 info.si_code = ILL_ILLOPC; 348 info.si_addr = pc; 349 350 arm64_notify_die("Oops - undefined instruction", regs, &info, 0); 351 } 352 353 long compat_arm_syscall(struct pt_regs *regs); 354 355 asmlinkage long do_ni_syscall(struct pt_regs *regs) 356 { 357 #ifdef CONFIG_COMPAT 358 long ret; 359 if (is_compat_task()) { 360 ret = compat_arm_syscall(regs); 361 if (ret != -ENOSYS) 362 return ret; 363 } 364 #endif 365 366 if (show_unhandled_signals && printk_ratelimit()) { 367 pr_info("%s[%d]: syscall %d\n", current->comm, 368 task_pid_nr(current), (int)regs->syscallno); 369 dump_instr("", regs); 370 if (user_mode(regs)) 371 __show_regs(regs); 372 } 373 374 return sys_ni_syscall(); 375 } 376 377 static const char *esr_class_str[] = { 378 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC", 379 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized", 380 [ESR_ELx_EC_WFx] = "WFI/WFE", 381 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC", 382 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC", 383 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC", 384 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC", 385 [ESR_ELx_EC_FP_ASIMD] = "ASIMD", 386 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS", 387 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC", 388 [ESR_ELx_EC_ILL] = "PSTATE.IL", 389 [ESR_ELx_EC_SVC32] = "SVC (AArch32)", 390 [ESR_ELx_EC_HVC32] = "HVC (AArch32)", 391 [ESR_ELx_EC_SMC32] = "SMC (AArch32)", 392 [ESR_ELx_EC_SVC64] = "SVC (AArch64)", 393 [ESR_ELx_EC_HVC64] = "HVC (AArch64)", 394 [ESR_ELx_EC_SMC64] = "SMC (AArch64)", 395 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)", 396 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF", 397 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)", 398 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)", 399 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment", 400 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)", 401 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)", 402 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment", 403 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)", 404 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)", 405 [ESR_ELx_EC_SERROR] = "SError", 406 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)", 407 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)", 408 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)", 409 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)", 410 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)", 411 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)", 412 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)", 413 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)", 414 [ESR_ELx_EC_BRK64] = "BRK (AArch64)", 415 }; 416 417 const char *esr_get_class_string(u32 esr) 418 { 419 return esr_class_str[esr >> ESR_ELx_EC_SHIFT]; 420 } 421 422 /* 423 * bad_mode handles the impossible case in the exception vector. 424 */ 425 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) 426 { 427 siginfo_t info; 428 void __user *pc = (void __user *)instruction_pointer(regs); 429 console_verbose(); 430 431 pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n", 432 handler[reason], esr, esr_get_class_string(esr)); 433 __show_regs(regs); 434 435 info.si_signo = SIGILL; 436 info.si_errno = 0; 437 info.si_code = ILL_ILLOPC; 438 info.si_addr = pc; 439 440 arm64_notify_die("Oops - bad mode", regs, &info, 0); 441 } 442 443 void __pte_error(const char *file, int line, unsigned long val) 444 { 445 pr_crit("%s:%d: bad pte %016lx.\n", file, line, val); 446 } 447 448 void __pmd_error(const char *file, int line, unsigned long val) 449 { 450 pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val); 451 } 452 453 void __pud_error(const char *file, int line, unsigned long val) 454 { 455 pr_crit("%s:%d: bad pud %016lx.\n", file, line, val); 456 } 457 458 void __pgd_error(const char *file, int line, unsigned long val) 459 { 460 pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val); 461 } 462 463 void __init trap_init(void) 464 { 465 return; 466 } 467