1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/arch/arm/kernel/traps.c 4 * 5 * Copyright (C) 1995-2009 Russell King 6 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds 7 * 8 * 'traps.c' handles hardware exceptions after we have saved some state in 9 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably 10 * kill the offending process. 11 */ 12 #include <linux/signal.h> 13 #include <linux/personality.h> 14 #include <linux/kallsyms.h> 15 #include <linux/spinlock.h> 16 #include <linux/uaccess.h> 17 #include <linux/hardirq.h> 18 #include <linux/kdebug.h> 19 #include <linux/kprobes.h> 20 #include <linux/module.h> 21 #include <linux/kexec.h> 22 #include <linux/bug.h> 23 #include <linux/delay.h> 24 #include <linux/init.h> 25 #include <linux/sched/signal.h> 26 #include <linux/sched/debug.h> 27 #include <linux/sched/task_stack.h> 28 #include <linux/irq.h> 29 30 #include <linux/atomic.h> 31 #include <asm/cacheflush.h> 32 #include <asm/exception.h> 33 #include <asm/unistd.h> 34 #include <asm/traps.h> 35 #include <asm/ptrace.h> 36 #include <asm/unwind.h> 37 #include <asm/tls.h> 38 #include <asm/system_misc.h> 39 #include <asm/opcodes.h> 40 41 42 static const char *handler[]= { 43 "prefetch abort", 44 "data abort", 45 "address exception", 46 "interrupt", 47 "undefined instruction", 48 }; 49 50 void *vectors_page; 51 52 #ifdef CONFIG_DEBUG_USER 53 unsigned int user_debug; 54 55 static int __init user_debug_setup(char *str) 56 { 57 get_option(&str, &user_debug); 58 return 1; 59 } 60 __setup("user_debug=", user_debug_setup); 61 #endif 62 63 static void dump_mem(const char *, const char *, unsigned long, unsigned long); 64 65 void dump_backtrace_entry(unsigned long where, unsigned long from, 66 unsigned long frame, const char *loglvl) 67 { 68 unsigned long end = frame + 4 + sizeof(struct pt_regs); 69 70 #ifndef CONFIG_KALLSYMS 71 printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n", 72 loglvl, where, from); 73 #elif defined CONFIG_BACKTRACE_VERBOSE 74 printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", 75 loglvl, where, (void *)where, from, (void *)from); 76 #else 77 printk("%s %ps from %pS\n", loglvl, (void *)where, (void *)from); 78 #endif 79 80 if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE)) 81 dump_mem(loglvl, "Exception stack", frame + 4, end); 82 } 83 84 void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl) 85 { 86 char str[80], *p; 87 unsigned int x; 88 int reg; 89 90 for (reg = 10, x = 0, p = str; reg >= 0; reg--) { 91 if (instruction & BIT(reg)) { 92 p += sprintf(p, " r%d:%08x", reg, *stack--); 93 if (++x == 6) { 94 x = 0; 95 p = str; 96 printk("%s%s\n", loglvl, str); 97 } 98 } 99 } 100 if (p != str) 101 printk("%s%s\n", loglvl, str); 102 } 103 104 #ifndef CONFIG_ARM_UNWIND 105 /* 106 * Stack pointers should always be within the kernels view of 107 * physical memory. If it is not there, then we can't dump 108 * out any information relating to the stack. 109 */ 110 static int verify_stack(unsigned long sp) 111 { 112 if (sp < PAGE_OFFSET || 113 (sp > (unsigned long)high_memory && high_memory != NULL)) 114 return -EFAULT; 115 116 return 0; 117 } 118 #endif 119 120 /* 121 * Dump out the contents of some memory nicely... 122 */ 123 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 124 unsigned long top) 125 { 126 unsigned long first; 127 int i; 128 129 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 130 131 for (first = bottom & ~31; first < top; first += 32) { 132 unsigned long p; 133 char str[sizeof(" 12345678") * 8 + 1]; 134 135 memset(str, ' ', sizeof(str)); 136 str[sizeof(str) - 1] = '\0'; 137 138 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 139 if (p >= bottom && p < top) { 140 unsigned long val; 141 if (!get_kernel_nofault(val, (unsigned long *)p)) 142 sprintf(str + i * 9, " %08lx", val); 143 else 144 sprintf(str + i * 9, " ????????"); 145 } 146 } 147 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 148 } 149 } 150 151 static void dump_instr(const char *lvl, struct pt_regs *regs) 152 { 153 unsigned long addr = instruction_pointer(regs); 154 const int thumb = thumb_mode(regs); 155 const int width = thumb ? 4 : 8; 156 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 157 int i; 158 159 /* 160 * Note that we now dump the code first, just in case the backtrace 161 * kills us. 162 */ 163 164 for (i = -4; i < 1 + !!thumb; i++) { 165 unsigned int val, bad; 166 167 if (!user_mode(regs)) { 168 if (thumb) { 169 u16 val16; 170 bad = get_kernel_nofault(val16, &((u16 *)addr)[i]); 171 val = val16; 172 } else { 173 bad = get_kernel_nofault(val, &((u32 *)addr)[i]); 174 } 175 } else { 176 if (thumb) 177 bad = get_user(val, &((u16 *)addr)[i]); 178 else 179 bad = get_user(val, &((u32 *)addr)[i]); 180 } 181 182 if (!bad) 183 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 184 width, val); 185 else { 186 p += sprintf(p, "bad PC value"); 187 break; 188 } 189 } 190 printk("%sCode: %s\n", lvl, str); 191 } 192 193 #ifdef CONFIG_ARM_UNWIND 194 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, 195 const char *loglvl) 196 { 197 unwind_backtrace(regs, tsk, loglvl); 198 } 199 #else 200 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, 201 const char *loglvl) 202 { 203 unsigned int fp, mode; 204 int ok = 1; 205 206 printk("%sBacktrace: ", loglvl); 207 208 if (!tsk) 209 tsk = current; 210 211 if (regs) { 212 fp = frame_pointer(regs); 213 mode = processor_mode(regs); 214 } else if (tsk != current) { 215 fp = thread_saved_fp(tsk); 216 mode = 0x10; 217 } else { 218 asm("mov %0, fp" : "=r" (fp) : : "cc"); 219 mode = 0x10; 220 } 221 222 if (!fp) { 223 pr_cont("no frame pointer"); 224 ok = 0; 225 } else if (verify_stack(fp)) { 226 pr_cont("invalid frame pointer 0x%08x", fp); 227 ok = 0; 228 } else if (fp < (unsigned long)end_of_stack(tsk)) 229 pr_cont("frame pointer underflow"); 230 pr_cont("\n"); 231 232 if (ok) 233 c_backtrace(fp, mode, loglvl); 234 } 235 #endif 236 237 void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl) 238 { 239 dump_backtrace(NULL, tsk, loglvl); 240 barrier(); 241 } 242 243 #ifdef CONFIG_PREEMPT 244 #define S_PREEMPT " PREEMPT" 245 #elif defined(CONFIG_PREEMPT_RT) 246 #define S_PREEMPT " PREEMPT_RT" 247 #else 248 #define S_PREEMPT "" 249 #endif 250 #ifdef CONFIG_SMP 251 #define S_SMP " SMP" 252 #else 253 #define S_SMP "" 254 #endif 255 #ifdef CONFIG_THUMB2_KERNEL 256 #define S_ISA " THUMB2" 257 #else 258 #define S_ISA " ARM" 259 #endif 260 261 static int __die(const char *str, int err, struct pt_regs *regs) 262 { 263 struct task_struct *tsk = current; 264 static int die_counter; 265 int ret; 266 267 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", 268 str, err, ++die_counter); 269 270 /* trap and error numbers are mostly meaningless on ARM */ 271 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 272 if (ret == NOTIFY_STOP) 273 return 1; 274 275 print_modules(); 276 __show_regs(regs); 277 __show_regs_alloc_free(regs); 278 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 279 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); 280 281 if (!user_mode(regs) || in_interrupt()) { 282 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 283 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 284 dump_backtrace(regs, tsk, KERN_EMERG); 285 dump_instr(KERN_EMERG, regs); 286 } 287 288 return 0; 289 } 290 291 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; 292 static int die_owner = -1; 293 static unsigned int die_nest_count; 294 295 static unsigned long oops_begin(void) 296 { 297 int cpu; 298 unsigned long flags; 299 300 oops_enter(); 301 302 /* racy, but better than risking deadlock. */ 303 raw_local_irq_save(flags); 304 cpu = smp_processor_id(); 305 if (!arch_spin_trylock(&die_lock)) { 306 if (cpu == die_owner) 307 /* nested oops. should stop eventually */; 308 else 309 arch_spin_lock(&die_lock); 310 } 311 die_nest_count++; 312 die_owner = cpu; 313 console_verbose(); 314 bust_spinlocks(1); 315 return flags; 316 } 317 318 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) 319 { 320 if (regs && kexec_should_crash(current)) 321 crash_kexec(regs); 322 323 bust_spinlocks(0); 324 die_owner = -1; 325 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 326 die_nest_count--; 327 if (!die_nest_count) 328 /* Nest count reaches zero, release the lock. */ 329 arch_spin_unlock(&die_lock); 330 raw_local_irq_restore(flags); 331 oops_exit(); 332 333 if (in_interrupt()) 334 panic("Fatal exception in interrupt"); 335 if (panic_on_oops) 336 panic("Fatal exception"); 337 if (signr) 338 make_task_dead(signr); 339 } 340 341 /* 342 * This function is protected against re-entrancy. 343 */ 344 void die(const char *str, struct pt_regs *regs, int err) 345 { 346 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; 347 unsigned long flags = oops_begin(); 348 int sig = SIGSEGV; 349 350 if (!user_mode(regs)) 351 bug_type = report_bug(regs->ARM_pc, regs); 352 if (bug_type != BUG_TRAP_TYPE_NONE) 353 str = "Oops - BUG"; 354 355 if (__die(str, err, regs)) 356 sig = 0; 357 358 oops_end(flags, regs, sig); 359 } 360 361 void arm_notify_die(const char *str, struct pt_regs *regs, 362 int signo, int si_code, void __user *addr, 363 unsigned long err, unsigned long trap) 364 { 365 if (user_mode(regs)) { 366 current->thread.error_code = err; 367 current->thread.trap_no = trap; 368 369 force_sig_fault(signo, si_code, addr); 370 } else { 371 die(str, regs, err); 372 } 373 } 374 375 #ifdef CONFIG_GENERIC_BUG 376 377 int is_valid_bugaddr(unsigned long pc) 378 { 379 #ifdef CONFIG_THUMB2_KERNEL 380 u16 bkpt; 381 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); 382 #else 383 u32 bkpt; 384 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); 385 #endif 386 387 if (get_kernel_nofault(bkpt, (void *)pc)) 388 return 0; 389 390 return bkpt == insn; 391 } 392 393 #endif 394 395 static LIST_HEAD(undef_hook); 396 static DEFINE_RAW_SPINLOCK(undef_lock); 397 398 void register_undef_hook(struct undef_hook *hook) 399 { 400 unsigned long flags; 401 402 raw_spin_lock_irqsave(&undef_lock, flags); 403 list_add(&hook->node, &undef_hook); 404 raw_spin_unlock_irqrestore(&undef_lock, flags); 405 } 406 407 void unregister_undef_hook(struct undef_hook *hook) 408 { 409 unsigned long flags; 410 411 raw_spin_lock_irqsave(&undef_lock, flags); 412 list_del(&hook->node); 413 raw_spin_unlock_irqrestore(&undef_lock, flags); 414 } 415 416 static nokprobe_inline 417 int call_undef_hook(struct pt_regs *regs, unsigned int instr) 418 { 419 struct undef_hook *hook; 420 unsigned long flags; 421 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 422 423 raw_spin_lock_irqsave(&undef_lock, flags); 424 list_for_each_entry(hook, &undef_hook, node) 425 if ((instr & hook->instr_mask) == hook->instr_val && 426 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 427 fn = hook->fn; 428 raw_spin_unlock_irqrestore(&undef_lock, flags); 429 430 return fn ? fn(regs, instr) : 1; 431 } 432 433 asmlinkage void do_undefinstr(struct pt_regs *regs) 434 { 435 unsigned int instr; 436 void __user *pc; 437 438 pc = (void __user *)instruction_pointer(regs); 439 440 if (processor_mode(regs) == SVC_MODE) { 441 #ifdef CONFIG_THUMB2_KERNEL 442 if (thumb_mode(regs)) { 443 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); 444 if (is_wide_instruction(instr)) { 445 u16 inst2; 446 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); 447 instr = __opcode_thumb32_compose(instr, inst2); 448 } 449 } else 450 #endif 451 instr = __mem_to_opcode_arm(*(u32 *) pc); 452 } else if (thumb_mode(regs)) { 453 if (get_user(instr, (u16 __user *)pc)) 454 goto die_sig; 455 instr = __mem_to_opcode_thumb16(instr); 456 if (is_wide_instruction(instr)) { 457 unsigned int instr2; 458 if (get_user(instr2, (u16 __user *)pc+1)) 459 goto die_sig; 460 instr2 = __mem_to_opcode_thumb16(instr2); 461 instr = __opcode_thumb32_compose(instr, instr2); 462 } 463 } else { 464 if (get_user(instr, (u32 __user *)pc)) 465 goto die_sig; 466 instr = __mem_to_opcode_arm(instr); 467 } 468 469 if (call_undef_hook(regs, instr) == 0) 470 return; 471 472 die_sig: 473 #ifdef CONFIG_DEBUG_USER 474 if (user_debug & UDBG_UNDEFINED) { 475 pr_info("%s (%d): undefined instruction: pc=%p\n", 476 current->comm, task_pid_nr(current), pc); 477 __show_regs(regs); 478 dump_instr(KERN_INFO, regs); 479 } 480 #endif 481 arm_notify_die("Oops - undefined instruction", regs, 482 SIGILL, ILL_ILLOPC, pc, 0, 6); 483 } 484 NOKPROBE_SYMBOL(do_undefinstr) 485 486 /* 487 * Handle FIQ similarly to NMI on x86 systems. 488 * 489 * The runtime environment for NMIs is extremely restrictive 490 * (NMIs can pre-empt critical sections meaning almost all locking is 491 * forbidden) meaning this default FIQ handling must only be used in 492 * circumstances where non-maskability improves robustness, such as 493 * watchdog or debug logic. 494 * 495 * This handler is not appropriate for general purpose use in drivers 496 * platform code and can be overrideen using set_fiq_handler. 497 */ 498 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) 499 { 500 struct pt_regs *old_regs = set_irq_regs(regs); 501 502 nmi_enter(); 503 504 /* nop. FIQ handlers for special arch/arm features can be added here. */ 505 506 nmi_exit(); 507 508 set_irq_regs(old_regs); 509 } 510 511 /* 512 * bad_mode handles the impossible case in the vectors. If you see one of 513 * these, then it's extremely serious, and could mean you have buggy hardware. 514 * It never returns, and never tries to sync. We hope that we can at least 515 * dump out some state information... 516 */ 517 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 518 { 519 console_verbose(); 520 521 pr_crit("Bad mode in %s handler detected\n", handler[reason]); 522 523 die("Oops - bad mode", regs, 0); 524 local_irq_disable(); 525 panic("bad mode"); 526 } 527 528 static int bad_syscall(int n, struct pt_regs *regs) 529 { 530 if ((current->personality & PER_MASK) != PER_LINUX) { 531 send_sig(SIGSEGV, current, 1); 532 return regs->ARM_r0; 533 } 534 535 #ifdef CONFIG_DEBUG_USER 536 if (user_debug & UDBG_SYSCALL) { 537 pr_err("[%d] %s: obsolete system call %08x.\n", 538 task_pid_nr(current), current->comm, n); 539 dump_instr(KERN_ERR, regs); 540 } 541 #endif 542 543 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP, 544 (void __user *)instruction_pointer(regs) - 545 (thumb_mode(regs) ? 2 : 4), 546 n, 0); 547 548 return regs->ARM_r0; 549 } 550 551 static inline int 552 __do_cache_op(unsigned long start, unsigned long end) 553 { 554 int ret; 555 556 do { 557 unsigned long chunk = min(PAGE_SIZE, end - start); 558 559 if (fatal_signal_pending(current)) 560 return 0; 561 562 ret = flush_icache_user_range(start, start + chunk); 563 if (ret) 564 return ret; 565 566 cond_resched(); 567 start += chunk; 568 } while (start < end); 569 570 return 0; 571 } 572 573 static inline int 574 do_cache_op(unsigned long start, unsigned long end, int flags) 575 { 576 if (end < start || flags) 577 return -EINVAL; 578 579 if (!access_ok(start, end - start)) 580 return -EFAULT; 581 582 return __do_cache_op(start, end); 583 } 584 585 /* 586 * Handle all unrecognised system calls. 587 * 0x9f0000 - 0x9fffff are some more esoteric system calls 588 */ 589 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 590 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 591 { 592 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 593 return bad_syscall(no, regs); 594 595 switch (no & 0xffff) { 596 case 0: /* branch through 0 */ 597 arm_notify_die("branch through zero", regs, 598 SIGSEGV, SEGV_MAPERR, NULL, 0, 0); 599 return 0; 600 601 case NR(breakpoint): /* SWI BREAK_POINT */ 602 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 603 ptrace_break(regs); 604 return regs->ARM_r0; 605 606 /* 607 * Flush a region from virtual address 'r0' to virtual address 'r1' 608 * _exclusive_. There is no alignment requirement on either address; 609 * user space does not need to know the hardware cache layout. 610 * 611 * r2 contains flags. It should ALWAYS be passed as ZERO until it 612 * is defined to be something else. For now we ignore it, but may 613 * the fires of hell burn in your belly if you break this rule. ;) 614 * 615 * (at a later date, we may want to allow this call to not flush 616 * various aspects of the cache. Passing '0' will guarantee that 617 * everything necessary gets flushed to maintain consistency in 618 * the specified region). 619 */ 620 case NR(cacheflush): 621 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 622 623 case NR(usr26): 624 if (!(elf_hwcap & HWCAP_26BIT)) 625 break; 626 regs->ARM_cpsr &= ~MODE32_BIT; 627 return regs->ARM_r0; 628 629 case NR(usr32): 630 if (!(elf_hwcap & HWCAP_26BIT)) 631 break; 632 regs->ARM_cpsr |= MODE32_BIT; 633 return regs->ARM_r0; 634 635 case NR(set_tls): 636 set_tls(regs->ARM_r0); 637 return 0; 638 639 case NR(get_tls): 640 return current_thread_info()->tp_value[0]; 641 642 default: 643 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 644 if not implemented, rather than raising SIGILL. This 645 way the calling program can gracefully determine whether 646 a feature is supported. */ 647 if ((no & 0xffff) <= 0x7ff) 648 return -ENOSYS; 649 break; 650 } 651 #ifdef CONFIG_DEBUG_USER 652 /* 653 * experience shows that these seem to indicate that 654 * something catastrophic has happened 655 */ 656 if (user_debug & UDBG_SYSCALL) { 657 pr_err("[%d] %s: arm syscall %d\n", 658 task_pid_nr(current), current->comm, no); 659 dump_instr(KERN_ERR, regs); 660 if (user_mode(regs)) { 661 __show_regs(regs); 662 c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR); 663 } 664 } 665 #endif 666 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP, 667 (void __user *)instruction_pointer(regs) - 668 (thumb_mode(regs) ? 2 : 4), 669 no, 0); 670 return 0; 671 } 672 673 #ifdef CONFIG_TLS_REG_EMUL 674 675 /* 676 * We might be running on an ARMv6+ processor which should have the TLS 677 * register but for some reason we can't use it, or maybe an SMP system 678 * using a pre-ARMv6 processor (there are apparently a few prototypes like 679 * that in existence) and therefore access to that register must be 680 * emulated. 681 */ 682 683 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 684 { 685 int reg = (instr >> 12) & 15; 686 if (reg == 15) 687 return 1; 688 regs->uregs[reg] = current_thread_info()->tp_value[0]; 689 regs->ARM_pc += 4; 690 return 0; 691 } 692 693 static struct undef_hook arm_mrc_hook = { 694 .instr_mask = 0x0fff0fff, 695 .instr_val = 0x0e1d0f70, 696 .cpsr_mask = PSR_T_BIT, 697 .cpsr_val = 0, 698 .fn = get_tp_trap, 699 }; 700 701 static int __init arm_mrc_hook_init(void) 702 { 703 register_undef_hook(&arm_mrc_hook); 704 return 0; 705 } 706 707 late_initcall(arm_mrc_hook_init); 708 709 #endif 710 711 /* 712 * A data abort trap was taken, but we did not handle the instruction. 713 * Try to abort the user program, or panic if it was the kernel. 714 */ 715 asmlinkage void 716 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 717 { 718 unsigned long addr = instruction_pointer(regs); 719 720 #ifdef CONFIG_DEBUG_USER 721 if (user_debug & UDBG_BADABORT) { 722 pr_err("8<--- cut here ---\n"); 723 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", 724 task_pid_nr(current), current->comm, code, instr); 725 dump_instr(KERN_ERR, regs); 726 show_pte(KERN_ERR, current->mm, addr); 727 } 728 #endif 729 730 arm_notify_die("unknown data abort code", regs, 731 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0); 732 } 733 734 void __readwrite_bug(const char *fn) 735 { 736 pr_err("%s called, but not implemented\n", fn); 737 BUG(); 738 } 739 EXPORT_SYMBOL(__readwrite_bug); 740 741 void __pte_error(const char *file, int line, pte_t pte) 742 { 743 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 744 } 745 746 void __pmd_error(const char *file, int line, pmd_t pmd) 747 { 748 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 749 } 750 751 void __pgd_error(const char *file, int line, pgd_t pgd) 752 { 753 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 754 } 755 756 asmlinkage void __div0(void) 757 { 758 pr_err("Division by zero in kernel.\n"); 759 dump_stack(); 760 } 761 EXPORT_SYMBOL(__div0); 762 763 void abort(void) 764 { 765 BUG(); 766 767 /* if that doesn't kill us, halt */ 768 panic("Oops failed to kill thread"); 769 } 770 771 #ifdef CONFIG_KUSER_HELPERS 772 static void __init kuser_init(void *vectors) 773 { 774 extern char __kuser_helper_start[], __kuser_helper_end[]; 775 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 776 777 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 778 779 /* 780 * vectors + 0xfe0 = __kuser_get_tls 781 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 782 */ 783 if (tls_emu || has_tls_reg) 784 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); 785 } 786 #else 787 static inline void __init kuser_init(void *vectors) 788 { 789 } 790 #endif 791 792 void __init early_trap_init(void *vectors_base) 793 { 794 #ifndef CONFIG_CPU_V7M 795 unsigned long vectors = (unsigned long)vectors_base; 796 extern char __stubs_start[], __stubs_end[]; 797 extern char __vectors_start[], __vectors_end[]; 798 unsigned i; 799 800 vectors_page = vectors_base; 801 802 /* 803 * Poison the vectors page with an undefined instruction. This 804 * instruction is chosen to be undefined for both ARM and Thumb 805 * ISAs. The Thumb version is an undefined instruction with a 806 * branch back to the undefined instruction. 807 */ 808 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) 809 ((u32 *)vectors_base)[i] = 0xe7fddef1; 810 811 /* 812 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 813 * into the vector page, mapped at 0xffff0000, and ensure these 814 * are visible to the instruction stream. 815 */ 816 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 817 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); 818 819 kuser_init(vectors_base); 820 821 flush_icache_range(vectors, vectors + PAGE_SIZE * 2); 822 #else /* ifndef CONFIG_CPU_V7M */ 823 /* 824 * on V7-M there is no need to copy the vector table to a dedicated 825 * memory area. The address is configurable and so a table in the kernel 826 * image can be used. 827 */ 828 #endif 829 } 830