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, unsigned long frame) 66 { 67 unsigned long end = frame + 4 + sizeof(struct pt_regs); 68 69 #ifdef CONFIG_KALLSYMS 70 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); 71 #else 72 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); 73 #endif 74 75 if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE)) 76 dump_mem("", "Exception stack", frame + 4, end); 77 } 78 79 void dump_backtrace_stm(u32 *stack, u32 instruction) 80 { 81 char str[80], *p; 82 unsigned int x; 83 int reg; 84 85 for (reg = 10, x = 0, p = str; reg >= 0; reg--) { 86 if (instruction & BIT(reg)) { 87 p += sprintf(p, " r%d:%08x", reg, *stack--); 88 if (++x == 6) { 89 x = 0; 90 p = str; 91 printk("%s\n", str); 92 } 93 } 94 } 95 if (p != str) 96 printk("%s\n", str); 97 } 98 99 #ifndef CONFIG_ARM_UNWIND 100 /* 101 * Stack pointers should always be within the kernels view of 102 * physical memory. If it is not there, then we can't dump 103 * out any information relating to the stack. 104 */ 105 static int verify_stack(unsigned long sp) 106 { 107 if (sp < PAGE_OFFSET || 108 (sp > (unsigned long)high_memory && high_memory != NULL)) 109 return -EFAULT; 110 111 return 0; 112 } 113 #endif 114 115 /* 116 * Dump out the contents of some memory nicely... 117 */ 118 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 119 unsigned long top) 120 { 121 unsigned long first; 122 mm_segment_t fs; 123 int i; 124 125 /* 126 * We need to switch to kernel mode so that we can use __get_user 127 * to safely read from kernel space. Note that we now dump the 128 * code first, just in case the backtrace kills us. 129 */ 130 fs = get_fs(); 131 set_fs(KERNEL_DS); 132 133 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 134 135 for (first = bottom & ~31; first < top; first += 32) { 136 unsigned long p; 137 char str[sizeof(" 12345678") * 8 + 1]; 138 139 memset(str, ' ', sizeof(str)); 140 str[sizeof(str) - 1] = '\0'; 141 142 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 143 if (p >= bottom && p < top) { 144 unsigned long val; 145 if (__get_user(val, (unsigned long *)p) == 0) 146 sprintf(str + i * 9, " %08lx", val); 147 else 148 sprintf(str + i * 9, " ????????"); 149 } 150 } 151 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 152 } 153 154 set_fs(fs); 155 } 156 157 static void __dump_instr(const char *lvl, struct pt_regs *regs) 158 { 159 unsigned long addr = instruction_pointer(regs); 160 const int thumb = thumb_mode(regs); 161 const int width = thumb ? 4 : 8; 162 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 163 int i; 164 165 /* 166 * Note that we now dump the code first, just in case the backtrace 167 * kills us. 168 */ 169 170 for (i = -4; i < 1 + !!thumb; i++) { 171 unsigned int val, bad; 172 173 if (thumb) 174 bad = get_user(val, &((u16 *)addr)[i]); 175 else 176 bad = get_user(val, &((u32 *)addr)[i]); 177 178 if (!bad) 179 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 180 width, val); 181 else { 182 p += sprintf(p, "bad PC value"); 183 break; 184 } 185 } 186 printk("%sCode: %s\n", lvl, str); 187 } 188 189 static void dump_instr(const char *lvl, struct pt_regs *regs) 190 { 191 mm_segment_t fs; 192 193 if (!user_mode(regs)) { 194 fs = get_fs(); 195 set_fs(KERNEL_DS); 196 __dump_instr(lvl, regs); 197 set_fs(fs); 198 } else { 199 __dump_instr(lvl, regs); 200 } 201 } 202 203 #ifdef CONFIG_ARM_UNWIND 204 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 205 { 206 unwind_backtrace(regs, tsk); 207 } 208 #else 209 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 210 { 211 unsigned int fp, mode; 212 int ok = 1; 213 214 printk("Backtrace: "); 215 216 if (!tsk) 217 tsk = current; 218 219 if (regs) { 220 fp = frame_pointer(regs); 221 mode = processor_mode(regs); 222 } else if (tsk != current) { 223 fp = thread_saved_fp(tsk); 224 mode = 0x10; 225 } else { 226 asm("mov %0, fp" : "=r" (fp) : : "cc"); 227 mode = 0x10; 228 } 229 230 if (!fp) { 231 pr_cont("no frame pointer"); 232 ok = 0; 233 } else if (verify_stack(fp)) { 234 pr_cont("invalid frame pointer 0x%08x", fp); 235 ok = 0; 236 } else if (fp < (unsigned long)end_of_stack(tsk)) 237 pr_cont("frame pointer underflow"); 238 pr_cont("\n"); 239 240 if (ok) 241 c_backtrace(fp, mode); 242 } 243 #endif 244 245 void show_stack(struct task_struct *tsk, unsigned long *sp) 246 { 247 dump_backtrace(NULL, tsk); 248 barrier(); 249 } 250 251 #ifdef CONFIG_PREEMPT 252 #define S_PREEMPT " PREEMPT" 253 #elif defined(CONFIG_PREEMPT_RT) 254 #define S_PREEMPT " PREEMPT_RT" 255 #else 256 #define S_PREEMPT "" 257 #endif 258 #ifdef CONFIG_SMP 259 #define S_SMP " SMP" 260 #else 261 #define S_SMP "" 262 #endif 263 #ifdef CONFIG_THUMB2_KERNEL 264 #define S_ISA " THUMB2" 265 #else 266 #define S_ISA " ARM" 267 #endif 268 269 static int __die(const char *str, int err, struct pt_regs *regs) 270 { 271 struct task_struct *tsk = current; 272 static int die_counter; 273 int ret; 274 275 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", 276 str, err, ++die_counter); 277 278 /* trap and error numbers are mostly meaningless on ARM */ 279 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 280 if (ret == NOTIFY_STOP) 281 return 1; 282 283 print_modules(); 284 __show_regs(regs); 285 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 286 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); 287 288 if (!user_mode(regs) || in_interrupt()) { 289 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 290 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 291 dump_backtrace(regs, tsk); 292 dump_instr(KERN_EMERG, regs); 293 } 294 295 return 0; 296 } 297 298 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; 299 static int die_owner = -1; 300 static unsigned int die_nest_count; 301 302 static unsigned long oops_begin(void) 303 { 304 int cpu; 305 unsigned long flags; 306 307 oops_enter(); 308 309 /* racy, but better than risking deadlock. */ 310 raw_local_irq_save(flags); 311 cpu = smp_processor_id(); 312 if (!arch_spin_trylock(&die_lock)) { 313 if (cpu == die_owner) 314 /* nested oops. should stop eventually */; 315 else 316 arch_spin_lock(&die_lock); 317 } 318 die_nest_count++; 319 die_owner = cpu; 320 console_verbose(); 321 bust_spinlocks(1); 322 return flags; 323 } 324 325 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) 326 { 327 if (regs && kexec_should_crash(current)) 328 crash_kexec(regs); 329 330 bust_spinlocks(0); 331 die_owner = -1; 332 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 333 die_nest_count--; 334 if (!die_nest_count) 335 /* Nest count reaches zero, release the lock. */ 336 arch_spin_unlock(&die_lock); 337 raw_local_irq_restore(flags); 338 oops_exit(); 339 340 if (in_interrupt()) 341 panic("Fatal exception in interrupt"); 342 if (panic_on_oops) 343 panic("Fatal exception"); 344 if (signr) 345 do_exit(signr); 346 } 347 348 /* 349 * This function is protected against re-entrancy. 350 */ 351 void die(const char *str, struct pt_regs *regs, int err) 352 { 353 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; 354 unsigned long flags = oops_begin(); 355 int sig = SIGSEGV; 356 357 if (!user_mode(regs)) 358 bug_type = report_bug(regs->ARM_pc, regs); 359 if (bug_type != BUG_TRAP_TYPE_NONE) 360 str = "Oops - BUG"; 361 362 if (__die(str, err, regs)) 363 sig = 0; 364 365 oops_end(flags, regs, sig); 366 } 367 368 void arm_notify_die(const char *str, struct pt_regs *regs, 369 int signo, int si_code, void __user *addr, 370 unsigned long err, unsigned long trap) 371 { 372 if (user_mode(regs)) { 373 current->thread.error_code = err; 374 current->thread.trap_no = trap; 375 376 force_sig_fault(signo, si_code, addr); 377 } else { 378 die(str, regs, err); 379 } 380 } 381 382 #ifdef CONFIG_GENERIC_BUG 383 384 int is_valid_bugaddr(unsigned long pc) 385 { 386 #ifdef CONFIG_THUMB2_KERNEL 387 u16 bkpt; 388 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); 389 #else 390 u32 bkpt; 391 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); 392 #endif 393 394 if (probe_kernel_address((unsigned *)pc, bkpt)) 395 return 0; 396 397 return bkpt == insn; 398 } 399 400 #endif 401 402 static LIST_HEAD(undef_hook); 403 static DEFINE_RAW_SPINLOCK(undef_lock); 404 405 void register_undef_hook(struct undef_hook *hook) 406 { 407 unsigned long flags; 408 409 raw_spin_lock_irqsave(&undef_lock, flags); 410 list_add(&hook->node, &undef_hook); 411 raw_spin_unlock_irqrestore(&undef_lock, flags); 412 } 413 414 void unregister_undef_hook(struct undef_hook *hook) 415 { 416 unsigned long flags; 417 418 raw_spin_lock_irqsave(&undef_lock, flags); 419 list_del(&hook->node); 420 raw_spin_unlock_irqrestore(&undef_lock, flags); 421 } 422 423 static nokprobe_inline 424 int call_undef_hook(struct pt_regs *regs, unsigned int instr) 425 { 426 struct undef_hook *hook; 427 unsigned long flags; 428 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 429 430 raw_spin_lock_irqsave(&undef_lock, flags); 431 list_for_each_entry(hook, &undef_hook, node) 432 if ((instr & hook->instr_mask) == hook->instr_val && 433 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 434 fn = hook->fn; 435 raw_spin_unlock_irqrestore(&undef_lock, flags); 436 437 return fn ? fn(regs, instr) : 1; 438 } 439 440 asmlinkage void do_undefinstr(struct pt_regs *regs) 441 { 442 unsigned int instr; 443 void __user *pc; 444 445 pc = (void __user *)instruction_pointer(regs); 446 447 if (processor_mode(regs) == SVC_MODE) { 448 #ifdef CONFIG_THUMB2_KERNEL 449 if (thumb_mode(regs)) { 450 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); 451 if (is_wide_instruction(instr)) { 452 u16 inst2; 453 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); 454 instr = __opcode_thumb32_compose(instr, inst2); 455 } 456 } else 457 #endif 458 instr = __mem_to_opcode_arm(*(u32 *) pc); 459 } else if (thumb_mode(regs)) { 460 if (get_user(instr, (u16 __user *)pc)) 461 goto die_sig; 462 instr = __mem_to_opcode_thumb16(instr); 463 if (is_wide_instruction(instr)) { 464 unsigned int instr2; 465 if (get_user(instr2, (u16 __user *)pc+1)) 466 goto die_sig; 467 instr2 = __mem_to_opcode_thumb16(instr2); 468 instr = __opcode_thumb32_compose(instr, instr2); 469 } 470 } else { 471 if (get_user(instr, (u32 __user *)pc)) 472 goto die_sig; 473 instr = __mem_to_opcode_arm(instr); 474 } 475 476 if (call_undef_hook(regs, instr) == 0) 477 return; 478 479 die_sig: 480 #ifdef CONFIG_DEBUG_USER 481 if (user_debug & UDBG_UNDEFINED) { 482 pr_info("%s (%d): undefined instruction: pc=%p\n", 483 current->comm, task_pid_nr(current), pc); 484 __show_regs(regs); 485 dump_instr(KERN_INFO, regs); 486 } 487 #endif 488 arm_notify_die("Oops - undefined instruction", regs, 489 SIGILL, ILL_ILLOPC, pc, 0, 6); 490 } 491 NOKPROBE_SYMBOL(do_undefinstr) 492 493 /* 494 * Handle FIQ similarly to NMI on x86 systems. 495 * 496 * The runtime environment for NMIs is extremely restrictive 497 * (NMIs can pre-empt critical sections meaning almost all locking is 498 * forbidden) meaning this default FIQ handling must only be used in 499 * circumstances where non-maskability improves robustness, such as 500 * watchdog or debug logic. 501 * 502 * This handler is not appropriate for general purpose use in drivers 503 * platform code and can be overrideen using set_fiq_handler. 504 */ 505 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) 506 { 507 struct pt_regs *old_regs = set_irq_regs(regs); 508 509 nmi_enter(); 510 511 /* nop. FIQ handlers for special arch/arm features can be added here. */ 512 513 nmi_exit(); 514 515 set_irq_regs(old_regs); 516 } 517 518 /* 519 * bad_mode handles the impossible case in the vectors. If you see one of 520 * these, then it's extremely serious, and could mean you have buggy hardware. 521 * It never returns, and never tries to sync. We hope that we can at least 522 * dump out some state information... 523 */ 524 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 525 { 526 console_verbose(); 527 528 pr_crit("Bad mode in %s handler detected\n", handler[reason]); 529 530 die("Oops - bad mode", regs, 0); 531 local_irq_disable(); 532 panic("bad mode"); 533 } 534 535 static int bad_syscall(int n, struct pt_regs *regs) 536 { 537 if ((current->personality & PER_MASK) != PER_LINUX) { 538 send_sig(SIGSEGV, current, 1); 539 return regs->ARM_r0; 540 } 541 542 #ifdef CONFIG_DEBUG_USER 543 if (user_debug & UDBG_SYSCALL) { 544 pr_err("[%d] %s: obsolete system call %08x.\n", 545 task_pid_nr(current), current->comm, n); 546 dump_instr(KERN_ERR, regs); 547 } 548 #endif 549 550 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP, 551 (void __user *)instruction_pointer(regs) - 552 (thumb_mode(regs) ? 2 : 4), 553 n, 0); 554 555 return regs->ARM_r0; 556 } 557 558 static inline int 559 __do_cache_op(unsigned long start, unsigned long end) 560 { 561 int ret; 562 563 do { 564 unsigned long chunk = min(PAGE_SIZE, end - start); 565 566 if (fatal_signal_pending(current)) 567 return 0; 568 569 ret = flush_cache_user_range(start, start + chunk); 570 if (ret) 571 return ret; 572 573 cond_resched(); 574 start += chunk; 575 } while (start < end); 576 577 return 0; 578 } 579 580 static inline int 581 do_cache_op(unsigned long start, unsigned long end, int flags) 582 { 583 if (end < start || flags) 584 return -EINVAL; 585 586 if (!access_ok(start, end - start)) 587 return -EFAULT; 588 589 return __do_cache_op(start, end); 590 } 591 592 /* 593 * Handle all unrecognised system calls. 594 * 0x9f0000 - 0x9fffff are some more esoteric system calls 595 */ 596 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 597 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 598 { 599 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 600 return bad_syscall(no, regs); 601 602 switch (no & 0xffff) { 603 case 0: /* branch through 0 */ 604 arm_notify_die("branch through zero", regs, 605 SIGSEGV, SEGV_MAPERR, NULL, 0, 0); 606 return 0; 607 608 case NR(breakpoint): /* SWI BREAK_POINT */ 609 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 610 ptrace_break(regs); 611 return regs->ARM_r0; 612 613 /* 614 * Flush a region from virtual address 'r0' to virtual address 'r1' 615 * _exclusive_. There is no alignment requirement on either address; 616 * user space does not need to know the hardware cache layout. 617 * 618 * r2 contains flags. It should ALWAYS be passed as ZERO until it 619 * is defined to be something else. For now we ignore it, but may 620 * the fires of hell burn in your belly if you break this rule. ;) 621 * 622 * (at a later date, we may want to allow this call to not flush 623 * various aspects of the cache. Passing '0' will guarantee that 624 * everything necessary gets flushed to maintain consistency in 625 * the specified region). 626 */ 627 case NR(cacheflush): 628 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 629 630 case NR(usr26): 631 if (!(elf_hwcap & HWCAP_26BIT)) 632 break; 633 regs->ARM_cpsr &= ~MODE32_BIT; 634 return regs->ARM_r0; 635 636 case NR(usr32): 637 if (!(elf_hwcap & HWCAP_26BIT)) 638 break; 639 regs->ARM_cpsr |= MODE32_BIT; 640 return regs->ARM_r0; 641 642 case NR(set_tls): 643 set_tls(regs->ARM_r0); 644 return 0; 645 646 case NR(get_tls): 647 return current_thread_info()->tp_value[0]; 648 649 default: 650 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 651 if not implemented, rather than raising SIGILL. This 652 way the calling program can gracefully determine whether 653 a feature is supported. */ 654 if ((no & 0xffff) <= 0x7ff) 655 return -ENOSYS; 656 break; 657 } 658 #ifdef CONFIG_DEBUG_USER 659 /* 660 * experience shows that these seem to indicate that 661 * something catastrophic has happened 662 */ 663 if (user_debug & UDBG_SYSCALL) { 664 pr_err("[%d] %s: arm syscall %d\n", 665 task_pid_nr(current), current->comm, no); 666 dump_instr("", regs); 667 if (user_mode(regs)) { 668 __show_regs(regs); 669 c_backtrace(frame_pointer(regs), processor_mode(regs)); 670 } 671 } 672 #endif 673 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP, 674 (void __user *)instruction_pointer(regs) - 675 (thumb_mode(regs) ? 2 : 4), 676 no, 0); 677 return 0; 678 } 679 680 #ifdef CONFIG_TLS_REG_EMUL 681 682 /* 683 * We might be running on an ARMv6+ processor which should have the TLS 684 * register but for some reason we can't use it, or maybe an SMP system 685 * using a pre-ARMv6 processor (there are apparently a few prototypes like 686 * that in existence) and therefore access to that register must be 687 * emulated. 688 */ 689 690 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 691 { 692 int reg = (instr >> 12) & 15; 693 if (reg == 15) 694 return 1; 695 regs->uregs[reg] = current_thread_info()->tp_value[0]; 696 regs->ARM_pc += 4; 697 return 0; 698 } 699 700 static struct undef_hook arm_mrc_hook = { 701 .instr_mask = 0x0fff0fff, 702 .instr_val = 0x0e1d0f70, 703 .cpsr_mask = PSR_T_BIT, 704 .cpsr_val = 0, 705 .fn = get_tp_trap, 706 }; 707 708 static int __init arm_mrc_hook_init(void) 709 { 710 register_undef_hook(&arm_mrc_hook); 711 return 0; 712 } 713 714 late_initcall(arm_mrc_hook_init); 715 716 #endif 717 718 /* 719 * A data abort trap was taken, but we did not handle the instruction. 720 * Try to abort the user program, or panic if it was the kernel. 721 */ 722 asmlinkage void 723 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 724 { 725 unsigned long addr = instruction_pointer(regs); 726 727 #ifdef CONFIG_DEBUG_USER 728 if (user_debug & UDBG_BADABORT) { 729 pr_err("8<--- cut here ---\n"); 730 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", 731 task_pid_nr(current), current->comm, code, instr); 732 dump_instr(KERN_ERR, regs); 733 show_pte(KERN_ERR, current->mm, addr); 734 } 735 #endif 736 737 arm_notify_die("unknown data abort code", regs, 738 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0); 739 } 740 741 void __readwrite_bug(const char *fn) 742 { 743 pr_err("%s called, but not implemented\n", fn); 744 BUG(); 745 } 746 EXPORT_SYMBOL(__readwrite_bug); 747 748 void __pte_error(const char *file, int line, pte_t pte) 749 { 750 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 751 } 752 753 void __pmd_error(const char *file, int line, pmd_t pmd) 754 { 755 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 756 } 757 758 void __pgd_error(const char *file, int line, pgd_t pgd) 759 { 760 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 761 } 762 763 asmlinkage void __div0(void) 764 { 765 pr_err("Division by zero in kernel.\n"); 766 dump_stack(); 767 } 768 EXPORT_SYMBOL(__div0); 769 770 void abort(void) 771 { 772 BUG(); 773 774 /* if that doesn't kill us, halt */ 775 panic("Oops failed to kill thread"); 776 } 777 778 void __init trap_init(void) 779 { 780 return; 781 } 782 783 #ifdef CONFIG_KUSER_HELPERS 784 static void __init kuser_init(void *vectors) 785 { 786 extern char __kuser_helper_start[], __kuser_helper_end[]; 787 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 788 789 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 790 791 /* 792 * vectors + 0xfe0 = __kuser_get_tls 793 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 794 */ 795 if (tls_emu || has_tls_reg) 796 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); 797 } 798 #else 799 static inline void __init kuser_init(void *vectors) 800 { 801 } 802 #endif 803 804 void __init early_trap_init(void *vectors_base) 805 { 806 #ifndef CONFIG_CPU_V7M 807 unsigned long vectors = (unsigned long)vectors_base; 808 extern char __stubs_start[], __stubs_end[]; 809 extern char __vectors_start[], __vectors_end[]; 810 unsigned i; 811 812 vectors_page = vectors_base; 813 814 /* 815 * Poison the vectors page with an undefined instruction. This 816 * instruction is chosen to be undefined for both ARM and Thumb 817 * ISAs. The Thumb version is an undefined instruction with a 818 * branch back to the undefined instruction. 819 */ 820 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) 821 ((u32 *)vectors_base)[i] = 0xe7fddef1; 822 823 /* 824 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 825 * into the vector page, mapped at 0xffff0000, and ensure these 826 * are visible to the instruction stream. 827 */ 828 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 829 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); 830 831 kuser_init(vectors_base); 832 833 flush_icache_range(vectors, vectors + PAGE_SIZE * 2); 834 #else /* ifndef CONFIG_CPU_V7M */ 835 /* 836 * on V7-M there is no need to copy the vector table to a dedicated 837 * memory area. The address is configurable and so a table in the kernel 838 * image can be used. 839 */ 840 #endif 841 } 842