1 /* 2 * linux/arch/arm/kernel/traps.c 3 * 4 * Copyright (C) 1995-2009 Russell King 5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds 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 * 'traps.c' handles hardware exceptions after we have saved some state in 12 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably 13 * kill the offending process. 14 */ 15 #include <linux/signal.h> 16 #include <linux/personality.h> 17 #include <linux/kallsyms.h> 18 #include <linux/spinlock.h> 19 #include <linux/uaccess.h> 20 #include <linux/hardirq.h> 21 #include <linux/kdebug.h> 22 #include <linux/kprobes.h> 23 #include <linux/module.h> 24 #include <linux/kexec.h> 25 #include <linux/bug.h> 26 #include <linux/delay.h> 27 #include <linux/init.h> 28 #include <linux/sched/signal.h> 29 #include <linux/sched/debug.h> 30 #include <linux/sched/task_stack.h> 31 #include <linux/irq.h> 32 33 #include <linux/atomic.h> 34 #include <asm/cacheflush.h> 35 #include <asm/exception.h> 36 #include <asm/unistd.h> 37 #include <asm/traps.h> 38 #include <asm/ptrace.h> 39 #include <asm/unwind.h> 40 #include <asm/tls.h> 41 #include <asm/system_misc.h> 42 #include <asm/opcodes.h> 43 44 45 static const char *handler[]= { 46 "prefetch abort", 47 "data abort", 48 "address exception", 49 "interrupt", 50 "undefined instruction", 51 }; 52 53 void *vectors_page; 54 55 #ifdef CONFIG_DEBUG_USER 56 unsigned int user_debug; 57 58 static int __init user_debug_setup(char *str) 59 { 60 get_option(&str, &user_debug); 61 return 1; 62 } 63 __setup("user_debug=", user_debug_setup); 64 #endif 65 66 static void dump_mem(const char *, const char *, unsigned long, unsigned long); 67 68 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) 69 { 70 #ifdef CONFIG_KALLSYMS 71 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); 72 #else 73 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); 74 #endif 75 76 if (in_entry_text(from)) 77 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); 78 } 79 80 void dump_backtrace_stm(u32 *stack, u32 instruction) 81 { 82 char str[80], *p; 83 unsigned int x; 84 int reg; 85 86 for (reg = 10, x = 0, p = str; reg >= 0; reg--) { 87 if (instruction & BIT(reg)) { 88 p += sprintf(p, " r%d:%08x", reg, *stack--); 89 if (++x == 6) { 90 x = 0; 91 p = str; 92 printk("%s\n", str); 93 } 94 } 95 } 96 if (p != str) 97 printk("%s\n", str); 98 } 99 100 #ifndef CONFIG_ARM_UNWIND 101 /* 102 * Stack pointers should always be within the kernels view of 103 * physical memory. If it is not there, then we can't dump 104 * out any information relating to the stack. 105 */ 106 static int verify_stack(unsigned long sp) 107 { 108 if (sp < PAGE_OFFSET || 109 (sp > (unsigned long)high_memory && high_memory != NULL)) 110 return -EFAULT; 111 112 return 0; 113 } 114 #endif 115 116 /* 117 * Dump out the contents of some memory nicely... 118 */ 119 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 120 unsigned long top) 121 { 122 unsigned long first; 123 mm_segment_t fs; 124 int i; 125 126 /* 127 * We need to switch to kernel mode so that we can use __get_user 128 * to safely read from kernel space. Note that we now dump the 129 * code first, just in case the backtrace kills us. 130 */ 131 fs = get_fs(); 132 set_fs(KERNEL_DS); 133 134 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 135 136 for (first = bottom & ~31; first < top; first += 32) { 137 unsigned long p; 138 char str[sizeof(" 12345678") * 8 + 1]; 139 140 memset(str, ' ', sizeof(str)); 141 str[sizeof(str) - 1] = '\0'; 142 143 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 144 if (p >= bottom && p < top) { 145 unsigned long val; 146 if (__get_user(val, (unsigned long *)p) == 0) 147 sprintf(str + i * 9, " %08lx", val); 148 else 149 sprintf(str + i * 9, " ????????"); 150 } 151 } 152 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 153 } 154 155 set_fs(fs); 156 } 157 158 static void __dump_instr(const char *lvl, struct pt_regs *regs) 159 { 160 unsigned long addr = instruction_pointer(regs); 161 const int thumb = thumb_mode(regs); 162 const int width = thumb ? 4 : 8; 163 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 164 int i; 165 166 /* 167 * Note that we now dump the code first, just in case the backtrace 168 * kills us. 169 */ 170 171 for (i = -4; i < 1 + !!thumb; i++) { 172 unsigned int val, bad; 173 174 if (thumb) 175 bad = get_user(val, &((u16 *)addr)[i]); 176 else 177 bad = get_user(val, &((u32 *)addr)[i]); 178 179 if (!bad) 180 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 181 width, val); 182 else { 183 p += sprintf(p, "bad PC value"); 184 break; 185 } 186 } 187 printk("%sCode: %s\n", lvl, str); 188 } 189 190 static void dump_instr(const char *lvl, struct pt_regs *regs) 191 { 192 mm_segment_t fs; 193 194 if (!user_mode(regs)) { 195 fs = get_fs(); 196 set_fs(KERNEL_DS); 197 __dump_instr(lvl, regs); 198 set_fs(fs); 199 } else { 200 __dump_instr(lvl, regs); 201 } 202 } 203 204 #ifdef CONFIG_ARM_UNWIND 205 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 206 { 207 unwind_backtrace(regs, tsk); 208 } 209 #else 210 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 211 { 212 unsigned int fp, mode; 213 int ok = 1; 214 215 printk("Backtrace: "); 216 217 if (!tsk) 218 tsk = current; 219 220 if (regs) { 221 fp = frame_pointer(regs); 222 mode = processor_mode(regs); 223 } else if (tsk != current) { 224 fp = thread_saved_fp(tsk); 225 mode = 0x10; 226 } else { 227 asm("mov %0, fp" : "=r" (fp) : : "cc"); 228 mode = 0x10; 229 } 230 231 if (!fp) { 232 pr_cont("no frame pointer"); 233 ok = 0; 234 } else if (verify_stack(fp)) { 235 pr_cont("invalid frame pointer 0x%08x", fp); 236 ok = 0; 237 } else if (fp < (unsigned long)end_of_stack(tsk)) 238 pr_cont("frame pointer underflow"); 239 pr_cont("\n"); 240 241 if (ok) 242 c_backtrace(fp, mode); 243 } 244 #endif 245 246 void show_stack(struct task_struct *tsk, unsigned long *sp) 247 { 248 dump_backtrace(NULL, tsk); 249 barrier(); 250 } 251 252 #ifdef CONFIG_PREEMPT 253 #define S_PREEMPT " PREEMPT" 254 #else 255 #define S_PREEMPT "" 256 #endif 257 #ifdef CONFIG_SMP 258 #define S_SMP " SMP" 259 #else 260 #define S_SMP "" 261 #endif 262 #ifdef CONFIG_THUMB2_KERNEL 263 #define S_ISA " THUMB2" 264 #else 265 #define S_ISA " ARM" 266 #endif 267 268 static int __die(const char *str, int err, struct pt_regs *regs) 269 { 270 struct task_struct *tsk = current; 271 static int die_counter; 272 int ret; 273 274 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", 275 str, err, ++die_counter); 276 277 /* trap and error numbers are mostly meaningless on ARM */ 278 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 279 if (ret == NOTIFY_STOP) 280 return 1; 281 282 print_modules(); 283 __show_regs(regs); 284 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 285 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); 286 287 if (!user_mode(regs) || in_interrupt()) { 288 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 289 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 290 dump_backtrace(regs, tsk); 291 dump_instr(KERN_EMERG, regs); 292 } 293 294 return 0; 295 } 296 297 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; 298 static int die_owner = -1; 299 static unsigned int die_nest_count; 300 301 static unsigned long oops_begin(void) 302 { 303 int cpu; 304 unsigned long flags; 305 306 oops_enter(); 307 308 /* racy, but better than risking deadlock. */ 309 raw_local_irq_save(flags); 310 cpu = smp_processor_id(); 311 if (!arch_spin_trylock(&die_lock)) { 312 if (cpu == die_owner) 313 /* nested oops. should stop eventually */; 314 else 315 arch_spin_lock(&die_lock); 316 } 317 die_nest_count++; 318 die_owner = cpu; 319 console_verbose(); 320 bust_spinlocks(1); 321 return flags; 322 } 323 324 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) 325 { 326 if (regs && kexec_should_crash(current)) 327 crash_kexec(regs); 328 329 bust_spinlocks(0); 330 die_owner = -1; 331 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 332 die_nest_count--; 333 if (!die_nest_count) 334 /* Nest count reaches zero, release the lock. */ 335 arch_spin_unlock(&die_lock); 336 raw_local_irq_restore(flags); 337 oops_exit(); 338 339 if (in_interrupt()) 340 panic("Fatal exception in interrupt"); 341 if (panic_on_oops) 342 panic("Fatal exception"); 343 if (signr) 344 do_exit(signr); 345 } 346 347 /* 348 * This function is protected against re-entrancy. 349 */ 350 void die(const char *str, struct pt_regs *regs, int err) 351 { 352 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; 353 unsigned long flags = oops_begin(); 354 int sig = SIGSEGV; 355 356 if (!user_mode(regs)) 357 bug_type = report_bug(regs->ARM_pc, regs); 358 if (bug_type != BUG_TRAP_TYPE_NONE) 359 str = "Oops - BUG"; 360 361 if (__die(str, err, regs)) 362 sig = 0; 363 364 oops_end(flags, regs, sig); 365 } 366 367 void arm_notify_die(const char *str, struct pt_regs *regs, 368 int signo, int si_code, void __user *addr, 369 unsigned long err, unsigned long trap) 370 { 371 if (user_mode(regs)) { 372 current->thread.error_code = err; 373 current->thread.trap_no = trap; 374 375 force_sig_fault(signo, si_code, addr, current); 376 } else { 377 die(str, regs, err); 378 } 379 } 380 381 #ifdef CONFIG_GENERIC_BUG 382 383 int is_valid_bugaddr(unsigned long pc) 384 { 385 #ifdef CONFIG_THUMB2_KERNEL 386 u16 bkpt; 387 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); 388 #else 389 u32 bkpt; 390 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); 391 #endif 392 393 if (probe_kernel_address((unsigned *)pc, bkpt)) 394 return 0; 395 396 return bkpt == insn; 397 } 398 399 #endif 400 401 static LIST_HEAD(undef_hook); 402 static DEFINE_RAW_SPINLOCK(undef_lock); 403 404 void register_undef_hook(struct undef_hook *hook) 405 { 406 unsigned long flags; 407 408 raw_spin_lock_irqsave(&undef_lock, flags); 409 list_add(&hook->node, &undef_hook); 410 raw_spin_unlock_irqrestore(&undef_lock, flags); 411 } 412 413 void unregister_undef_hook(struct undef_hook *hook) 414 { 415 unsigned long flags; 416 417 raw_spin_lock_irqsave(&undef_lock, flags); 418 list_del(&hook->node); 419 raw_spin_unlock_irqrestore(&undef_lock, flags); 420 } 421 422 static nokprobe_inline 423 int call_undef_hook(struct pt_regs *regs, unsigned int instr) 424 { 425 struct undef_hook *hook; 426 unsigned long flags; 427 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 428 429 raw_spin_lock_irqsave(&undef_lock, flags); 430 list_for_each_entry(hook, &undef_hook, node) 431 if ((instr & hook->instr_mask) == hook->instr_val && 432 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 433 fn = hook->fn; 434 raw_spin_unlock_irqrestore(&undef_lock, flags); 435 436 return fn ? fn(regs, instr) : 1; 437 } 438 439 asmlinkage void do_undefinstr(struct pt_regs *regs) 440 { 441 unsigned int instr; 442 void __user *pc; 443 444 pc = (void __user *)instruction_pointer(regs); 445 446 if (processor_mode(regs) == SVC_MODE) { 447 #ifdef CONFIG_THUMB2_KERNEL 448 if (thumb_mode(regs)) { 449 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); 450 if (is_wide_instruction(instr)) { 451 u16 inst2; 452 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); 453 instr = __opcode_thumb32_compose(instr, inst2); 454 } 455 } else 456 #endif 457 instr = __mem_to_opcode_arm(*(u32 *) pc); 458 } else if (thumb_mode(regs)) { 459 if (get_user(instr, (u16 __user *)pc)) 460 goto die_sig; 461 instr = __mem_to_opcode_thumb16(instr); 462 if (is_wide_instruction(instr)) { 463 unsigned int instr2; 464 if (get_user(instr2, (u16 __user *)pc+1)) 465 goto die_sig; 466 instr2 = __mem_to_opcode_thumb16(instr2); 467 instr = __opcode_thumb32_compose(instr, instr2); 468 } 469 } else { 470 if (get_user(instr, (u32 __user *)pc)) 471 goto die_sig; 472 instr = __mem_to_opcode_arm(instr); 473 } 474 475 if (call_undef_hook(regs, instr) == 0) 476 return; 477 478 die_sig: 479 #ifdef CONFIG_DEBUG_USER 480 if (user_debug & UDBG_UNDEFINED) { 481 pr_info("%s (%d): undefined instruction: pc=%p\n", 482 current->comm, task_pid_nr(current), pc); 483 __show_regs(regs); 484 dump_instr(KERN_INFO, regs); 485 } 486 #endif 487 arm_notify_die("Oops - undefined instruction", regs, 488 SIGILL, ILL_ILLOPC, pc, 0, 6); 489 } 490 NOKPROBE_SYMBOL(do_undefinstr) 491 492 /* 493 * Handle FIQ similarly to NMI on x86 systems. 494 * 495 * The runtime environment for NMIs is extremely restrictive 496 * (NMIs can pre-empt critical sections meaning almost all locking is 497 * forbidden) meaning this default FIQ handling must only be used in 498 * circumstances where non-maskability improves robustness, such as 499 * watchdog or debug logic. 500 * 501 * This handler is not appropriate for general purpose use in drivers 502 * platform code and can be overrideen using set_fiq_handler. 503 */ 504 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) 505 { 506 struct pt_regs *old_regs = set_irq_regs(regs); 507 508 nmi_enter(); 509 510 /* nop. FIQ handlers for special arch/arm features can be added here. */ 511 512 nmi_exit(); 513 514 set_irq_regs(old_regs); 515 } 516 517 /* 518 * bad_mode handles the impossible case in the vectors. If you see one of 519 * these, then it's extremely serious, and could mean you have buggy hardware. 520 * It never returns, and never tries to sync. We hope that we can at least 521 * dump out some state information... 522 */ 523 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 524 { 525 console_verbose(); 526 527 pr_crit("Bad mode in %s handler detected\n", handler[reason]); 528 529 die("Oops - bad mode", regs, 0); 530 local_irq_disable(); 531 panic("bad mode"); 532 } 533 534 static int bad_syscall(int n, struct pt_regs *regs) 535 { 536 if ((current->personality & PER_MASK) != PER_LINUX) { 537 send_sig(SIGSEGV, current, 1); 538 return regs->ARM_r0; 539 } 540 541 #ifdef CONFIG_DEBUG_USER 542 if (user_debug & UDBG_SYSCALL) { 543 pr_err("[%d] %s: obsolete system call %08x.\n", 544 task_pid_nr(current), current->comm, n); 545 dump_instr(KERN_ERR, regs); 546 } 547 #endif 548 549 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP, 550 (void __user *)instruction_pointer(regs) - 551 (thumb_mode(regs) ? 2 : 4), 552 n, 0); 553 554 return regs->ARM_r0; 555 } 556 557 static inline int 558 __do_cache_op(unsigned long start, unsigned long end) 559 { 560 int ret; 561 562 do { 563 unsigned long chunk = min(PAGE_SIZE, end - start); 564 565 if (fatal_signal_pending(current)) 566 return 0; 567 568 ret = flush_cache_user_range(start, start + chunk); 569 if (ret) 570 return ret; 571 572 cond_resched(); 573 start += chunk; 574 } while (start < end); 575 576 return 0; 577 } 578 579 static inline int 580 do_cache_op(unsigned long start, unsigned long end, int flags) 581 { 582 if (end < start || flags) 583 return -EINVAL; 584 585 if (!access_ok(start, end - start)) 586 return -EFAULT; 587 588 return __do_cache_op(start, end); 589 } 590 591 /* 592 * Handle all unrecognised system calls. 593 * 0x9f0000 - 0x9fffff are some more esoteric system calls 594 */ 595 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 596 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 597 { 598 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 599 return bad_syscall(no, regs); 600 601 switch (no & 0xffff) { 602 case 0: /* branch through 0 */ 603 arm_notify_die("branch through zero", regs, 604 SIGSEGV, SEGV_MAPERR, NULL, 0, 0); 605 return 0; 606 607 case NR(breakpoint): /* SWI BREAK_POINT */ 608 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 609 ptrace_break(current, regs); 610 return regs->ARM_r0; 611 612 /* 613 * Flush a region from virtual address 'r0' to virtual address 'r1' 614 * _exclusive_. There is no alignment requirement on either address; 615 * user space does not need to know the hardware cache layout. 616 * 617 * r2 contains flags. It should ALWAYS be passed as ZERO until it 618 * is defined to be something else. For now we ignore it, but may 619 * the fires of hell burn in your belly if you break this rule. ;) 620 * 621 * (at a later date, we may want to allow this call to not flush 622 * various aspects of the cache. Passing '0' will guarantee that 623 * everything necessary gets flushed to maintain consistency in 624 * the specified region). 625 */ 626 case NR(cacheflush): 627 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 628 629 case NR(usr26): 630 if (!(elf_hwcap & HWCAP_26BIT)) 631 break; 632 regs->ARM_cpsr &= ~MODE32_BIT; 633 return regs->ARM_r0; 634 635 case NR(usr32): 636 if (!(elf_hwcap & HWCAP_26BIT)) 637 break; 638 regs->ARM_cpsr |= MODE32_BIT; 639 return regs->ARM_r0; 640 641 case NR(set_tls): 642 set_tls(regs->ARM_r0); 643 return 0; 644 645 case NR(get_tls): 646 return current_thread_info()->tp_value[0]; 647 648 default: 649 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 650 if not implemented, rather than raising SIGILL. This 651 way the calling program can gracefully determine whether 652 a feature is supported. */ 653 if ((no & 0xffff) <= 0x7ff) 654 return -ENOSYS; 655 break; 656 } 657 #ifdef CONFIG_DEBUG_USER 658 /* 659 * experience shows that these seem to indicate that 660 * something catastrophic has happened 661 */ 662 if (user_debug & UDBG_SYSCALL) { 663 pr_err("[%d] %s: arm syscall %d\n", 664 task_pid_nr(current), current->comm, no); 665 dump_instr("", regs); 666 if (user_mode(regs)) { 667 __show_regs(regs); 668 c_backtrace(frame_pointer(regs), processor_mode(regs)); 669 } 670 } 671 #endif 672 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP, 673 (void __user *)instruction_pointer(regs) - 674 (thumb_mode(regs) ? 2 : 4), 675 no, 0); 676 return 0; 677 } 678 679 #ifdef CONFIG_TLS_REG_EMUL 680 681 /* 682 * We might be running on an ARMv6+ processor which should have the TLS 683 * register but for some reason we can't use it, or maybe an SMP system 684 * using a pre-ARMv6 processor (there are apparently a few prototypes like 685 * that in existence) and therefore access to that register must be 686 * emulated. 687 */ 688 689 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 690 { 691 int reg = (instr >> 12) & 15; 692 if (reg == 15) 693 return 1; 694 regs->uregs[reg] = current_thread_info()->tp_value[0]; 695 regs->ARM_pc += 4; 696 return 0; 697 } 698 699 static struct undef_hook arm_mrc_hook = { 700 .instr_mask = 0x0fff0fff, 701 .instr_val = 0x0e1d0f70, 702 .cpsr_mask = PSR_T_BIT, 703 .cpsr_val = 0, 704 .fn = get_tp_trap, 705 }; 706 707 static int __init arm_mrc_hook_init(void) 708 { 709 register_undef_hook(&arm_mrc_hook); 710 return 0; 711 } 712 713 late_initcall(arm_mrc_hook_init); 714 715 #endif 716 717 /* 718 * A data abort trap was taken, but we did not handle the instruction. 719 * Try to abort the user program, or panic if it was the kernel. 720 */ 721 asmlinkage void 722 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 723 { 724 unsigned long addr = instruction_pointer(regs); 725 726 #ifdef CONFIG_DEBUG_USER 727 if (user_debug & UDBG_BADABORT) { 728 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", 729 task_pid_nr(current), current->comm, code, instr); 730 dump_instr(KERN_ERR, regs); 731 show_pte(current->mm, addr); 732 } 733 #endif 734 735 arm_notify_die("unknown data abort code", regs, 736 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0); 737 } 738 739 void __readwrite_bug(const char *fn) 740 { 741 pr_err("%s called, but not implemented\n", fn); 742 BUG(); 743 } 744 EXPORT_SYMBOL(__readwrite_bug); 745 746 void __pte_error(const char *file, int line, pte_t pte) 747 { 748 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 749 } 750 751 void __pmd_error(const char *file, int line, pmd_t pmd) 752 { 753 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 754 } 755 756 void __pgd_error(const char *file, int line, pgd_t pgd) 757 { 758 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 759 } 760 761 asmlinkage void __div0(void) 762 { 763 pr_err("Division by zero in kernel.\n"); 764 dump_stack(); 765 } 766 EXPORT_SYMBOL(__div0); 767 768 void abort(void) 769 { 770 BUG(); 771 772 /* if that doesn't kill us, halt */ 773 panic("Oops failed to kill thread"); 774 } 775 776 void __init trap_init(void) 777 { 778 return; 779 } 780 781 #ifdef CONFIG_KUSER_HELPERS 782 static void __init kuser_init(void *vectors) 783 { 784 extern char __kuser_helper_start[], __kuser_helper_end[]; 785 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 786 787 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 788 789 /* 790 * vectors + 0xfe0 = __kuser_get_tls 791 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 792 */ 793 if (tls_emu || has_tls_reg) 794 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); 795 } 796 #else 797 static inline void __init kuser_init(void *vectors) 798 { 799 } 800 #endif 801 802 void __init early_trap_init(void *vectors_base) 803 { 804 #ifndef CONFIG_CPU_V7M 805 unsigned long vectors = (unsigned long)vectors_base; 806 extern char __stubs_start[], __stubs_end[]; 807 extern char __vectors_start[], __vectors_end[]; 808 unsigned i; 809 810 vectors_page = vectors_base; 811 812 /* 813 * Poison the vectors page with an undefined instruction. This 814 * instruction is chosen to be undefined for both ARM and Thumb 815 * ISAs. The Thumb version is an undefined instruction with a 816 * branch back to the undefined instruction. 817 */ 818 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) 819 ((u32 *)vectors_base)[i] = 0xe7fddef1; 820 821 /* 822 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 823 * into the vector page, mapped at 0xffff0000, and ensure these 824 * are visible to the instruction stream. 825 */ 826 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 827 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); 828 829 kuser_init(vectors_base); 830 831 flush_icache_range(vectors, vectors + PAGE_SIZE * 2); 832 #else /* ifndef CONFIG_CPU_V7M */ 833 /* 834 * on V7-M there is no need to copy the vector table to a dedicated 835 * memory area. The address is configurable and so a table in the kernel 836 * image can be used. 837 */ 838 #endif 839 } 840