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 #ifdef CONFIG_KALLSYMS 71 printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", 72 loglvl, where, (void *)where, from, (void *)from); 73 #else 74 printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n", 75 loglvl, where, from); 76 #endif 77 78 if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE)) 79 dump_mem(loglvl, "Exception stack", frame + 4, end); 80 } 81 82 void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl) 83 { 84 char str[80], *p; 85 unsigned int x; 86 int reg; 87 88 for (reg = 10, x = 0, p = str; reg >= 0; reg--) { 89 if (instruction & BIT(reg)) { 90 p += sprintf(p, " r%d:%08x", reg, *stack--); 91 if (++x == 6) { 92 x = 0; 93 p = str; 94 printk("%s%s\n", loglvl, str); 95 } 96 } 97 } 98 if (p != str) 99 printk("%s%s\n", loglvl, str); 100 } 101 102 #ifndef CONFIG_ARM_UNWIND 103 /* 104 * Stack pointers should always be within the kernels view of 105 * physical memory. If it is not there, then we can't dump 106 * out any information relating to the stack. 107 */ 108 static int verify_stack(unsigned long sp) 109 { 110 if (sp < PAGE_OFFSET || 111 (sp > (unsigned long)high_memory && high_memory != NULL)) 112 return -EFAULT; 113 114 return 0; 115 } 116 #endif 117 118 /* 119 * Dump out the contents of some memory nicely... 120 */ 121 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 122 unsigned long top) 123 { 124 unsigned long first; 125 mm_segment_t fs; 126 int i; 127 128 /* 129 * We need to switch to kernel mode so that we can use __get_user 130 * to safely read from kernel space. Note that we now dump the 131 * code first, just in case the backtrace kills us. 132 */ 133 fs = get_fs(); 134 set_fs(KERNEL_DS); 135 136 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 137 138 for (first = bottom & ~31; first < top; first += 32) { 139 unsigned long p; 140 char str[sizeof(" 12345678") * 8 + 1]; 141 142 memset(str, ' ', sizeof(str)); 143 str[sizeof(str) - 1] = '\0'; 144 145 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 146 if (p >= bottom && p < top) { 147 unsigned long val; 148 if (__get_user(val, (unsigned long *)p) == 0) 149 sprintf(str + i * 9, " %08lx", val); 150 else 151 sprintf(str + i * 9, " ????????"); 152 } 153 } 154 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 155 } 156 157 set_fs(fs); 158 } 159 160 static void __dump_instr(const char *lvl, struct pt_regs *regs) 161 { 162 unsigned long addr = instruction_pointer(regs); 163 const int thumb = thumb_mode(regs); 164 const int width = thumb ? 4 : 8; 165 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 166 int i; 167 168 /* 169 * Note that we now dump the code first, just in case the backtrace 170 * kills us. 171 */ 172 173 for (i = -4; i < 1 + !!thumb; i++) { 174 unsigned int val, bad; 175 176 if (thumb) 177 bad = get_user(val, &((u16 *)addr)[i]); 178 else 179 bad = get_user(val, &((u32 *)addr)[i]); 180 181 if (!bad) 182 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 183 width, val); 184 else { 185 p += sprintf(p, "bad PC value"); 186 break; 187 } 188 } 189 printk("%sCode: %s\n", lvl, str); 190 } 191 192 static void dump_instr(const char *lvl, struct pt_regs *regs) 193 { 194 mm_segment_t fs; 195 196 if (!user_mode(regs)) { 197 fs = get_fs(); 198 set_fs(KERNEL_DS); 199 __dump_instr(lvl, regs); 200 set_fs(fs); 201 } else { 202 __dump_instr(lvl, regs); 203 } 204 } 205 206 #ifdef CONFIG_ARM_UNWIND 207 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, 208 const char *loglvl) 209 { 210 unwind_backtrace(regs, tsk, loglvl); 211 } 212 #else 213 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk, 214 const char *loglvl) 215 { 216 unsigned int fp, mode; 217 int ok = 1; 218 219 printk("%sBacktrace: ", loglvl); 220 221 if (!tsk) 222 tsk = current; 223 224 if (regs) { 225 fp = frame_pointer(regs); 226 mode = processor_mode(regs); 227 } else if (tsk != current) { 228 fp = thread_saved_fp(tsk); 229 mode = 0x10; 230 } else { 231 asm("mov %0, fp" : "=r" (fp) : : "cc"); 232 mode = 0x10; 233 } 234 235 if (!fp) { 236 pr_cont("no frame pointer"); 237 ok = 0; 238 } else if (verify_stack(fp)) { 239 pr_cont("invalid frame pointer 0x%08x", fp); 240 ok = 0; 241 } else if (fp < (unsigned long)end_of_stack(tsk)) 242 pr_cont("frame pointer underflow"); 243 pr_cont("\n"); 244 245 if (ok) 246 c_backtrace(fp, mode, loglvl); 247 } 248 #endif 249 250 void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl) 251 { 252 dump_backtrace(NULL, tsk, loglvl); 253 barrier(); 254 } 255 256 #ifdef CONFIG_PREEMPT 257 #define S_PREEMPT " PREEMPT" 258 #elif defined(CONFIG_PREEMPT_RT) 259 #define S_PREEMPT " PREEMPT_RT" 260 #else 261 #define S_PREEMPT "" 262 #endif 263 #ifdef CONFIG_SMP 264 #define S_SMP " SMP" 265 #else 266 #define S_SMP "" 267 #endif 268 #ifdef CONFIG_THUMB2_KERNEL 269 #define S_ISA " THUMB2" 270 #else 271 #define S_ISA " ARM" 272 #endif 273 274 static int __die(const char *str, int err, struct pt_regs *regs) 275 { 276 struct task_struct *tsk = current; 277 static int die_counter; 278 int ret; 279 280 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", 281 str, err, ++die_counter); 282 283 /* trap and error numbers are mostly meaningless on ARM */ 284 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 285 if (ret == NOTIFY_STOP) 286 return 1; 287 288 print_modules(); 289 __show_regs(regs); 290 __show_regs_alloc_free(regs); 291 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 292 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); 293 294 if (!user_mode(regs) || in_interrupt()) { 295 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 296 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 297 dump_backtrace(regs, tsk, KERN_EMERG); 298 dump_instr(KERN_EMERG, regs); 299 } 300 301 return 0; 302 } 303 304 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; 305 static int die_owner = -1; 306 static unsigned int die_nest_count; 307 308 static unsigned long oops_begin(void) 309 { 310 int cpu; 311 unsigned long flags; 312 313 oops_enter(); 314 315 /* racy, but better than risking deadlock. */ 316 raw_local_irq_save(flags); 317 cpu = smp_processor_id(); 318 if (!arch_spin_trylock(&die_lock)) { 319 if (cpu == die_owner) 320 /* nested oops. should stop eventually */; 321 else 322 arch_spin_lock(&die_lock); 323 } 324 die_nest_count++; 325 die_owner = cpu; 326 console_verbose(); 327 bust_spinlocks(1); 328 return flags; 329 } 330 331 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) 332 { 333 if (regs && kexec_should_crash(current)) 334 crash_kexec(regs); 335 336 bust_spinlocks(0); 337 die_owner = -1; 338 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 339 die_nest_count--; 340 if (!die_nest_count) 341 /* Nest count reaches zero, release the lock. */ 342 arch_spin_unlock(&die_lock); 343 raw_local_irq_restore(flags); 344 oops_exit(); 345 346 if (in_interrupt()) 347 panic("Fatal exception in interrupt"); 348 if (panic_on_oops) 349 panic("Fatal exception"); 350 if (signr) 351 do_exit(signr); 352 } 353 354 /* 355 * This function is protected against re-entrancy. 356 */ 357 void die(const char *str, struct pt_regs *regs, int err) 358 { 359 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; 360 unsigned long flags = oops_begin(); 361 int sig = SIGSEGV; 362 363 if (!user_mode(regs)) 364 bug_type = report_bug(regs->ARM_pc, regs); 365 if (bug_type != BUG_TRAP_TYPE_NONE) 366 str = "Oops - BUG"; 367 368 if (__die(str, err, regs)) 369 sig = 0; 370 371 oops_end(flags, regs, sig); 372 } 373 374 void arm_notify_die(const char *str, struct pt_regs *regs, 375 int signo, int si_code, void __user *addr, 376 unsigned long err, unsigned long trap) 377 { 378 if (user_mode(regs)) { 379 current->thread.error_code = err; 380 current->thread.trap_no = trap; 381 382 force_sig_fault(signo, si_code, addr); 383 } else { 384 die(str, regs, err); 385 } 386 } 387 388 #ifdef CONFIG_GENERIC_BUG 389 390 int is_valid_bugaddr(unsigned long pc) 391 { 392 #ifdef CONFIG_THUMB2_KERNEL 393 u16 bkpt; 394 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); 395 #else 396 u32 bkpt; 397 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); 398 #endif 399 400 if (get_kernel_nofault(bkpt, (void *)pc)) 401 return 0; 402 403 return bkpt == insn; 404 } 405 406 #endif 407 408 static LIST_HEAD(undef_hook); 409 static DEFINE_RAW_SPINLOCK(undef_lock); 410 411 void register_undef_hook(struct undef_hook *hook) 412 { 413 unsigned long flags; 414 415 raw_spin_lock_irqsave(&undef_lock, flags); 416 list_add(&hook->node, &undef_hook); 417 raw_spin_unlock_irqrestore(&undef_lock, flags); 418 } 419 420 void unregister_undef_hook(struct undef_hook *hook) 421 { 422 unsigned long flags; 423 424 raw_spin_lock_irqsave(&undef_lock, flags); 425 list_del(&hook->node); 426 raw_spin_unlock_irqrestore(&undef_lock, flags); 427 } 428 429 static nokprobe_inline 430 int call_undef_hook(struct pt_regs *regs, unsigned int instr) 431 { 432 struct undef_hook *hook; 433 unsigned long flags; 434 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 435 436 raw_spin_lock_irqsave(&undef_lock, flags); 437 list_for_each_entry(hook, &undef_hook, node) 438 if ((instr & hook->instr_mask) == hook->instr_val && 439 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 440 fn = hook->fn; 441 raw_spin_unlock_irqrestore(&undef_lock, flags); 442 443 return fn ? fn(regs, instr) : 1; 444 } 445 446 asmlinkage void do_undefinstr(struct pt_regs *regs) 447 { 448 unsigned int instr; 449 void __user *pc; 450 451 pc = (void __user *)instruction_pointer(regs); 452 453 if (processor_mode(regs) == SVC_MODE) { 454 #ifdef CONFIG_THUMB2_KERNEL 455 if (thumb_mode(regs)) { 456 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); 457 if (is_wide_instruction(instr)) { 458 u16 inst2; 459 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); 460 instr = __opcode_thumb32_compose(instr, inst2); 461 } 462 } else 463 #endif 464 instr = __mem_to_opcode_arm(*(u32 *) pc); 465 } else if (thumb_mode(regs)) { 466 if (get_user(instr, (u16 __user *)pc)) 467 goto die_sig; 468 instr = __mem_to_opcode_thumb16(instr); 469 if (is_wide_instruction(instr)) { 470 unsigned int instr2; 471 if (get_user(instr2, (u16 __user *)pc+1)) 472 goto die_sig; 473 instr2 = __mem_to_opcode_thumb16(instr2); 474 instr = __opcode_thumb32_compose(instr, instr2); 475 } 476 } else { 477 if (get_user(instr, (u32 __user *)pc)) 478 goto die_sig; 479 instr = __mem_to_opcode_arm(instr); 480 } 481 482 if (call_undef_hook(regs, instr) == 0) 483 return; 484 485 die_sig: 486 #ifdef CONFIG_DEBUG_USER 487 if (user_debug & UDBG_UNDEFINED) { 488 pr_info("%s (%d): undefined instruction: pc=%p\n", 489 current->comm, task_pid_nr(current), pc); 490 __show_regs(regs); 491 dump_instr(KERN_INFO, regs); 492 } 493 #endif 494 arm_notify_die("Oops - undefined instruction", regs, 495 SIGILL, ILL_ILLOPC, pc, 0, 6); 496 } 497 NOKPROBE_SYMBOL(do_undefinstr) 498 499 /* 500 * Handle FIQ similarly to NMI on x86 systems. 501 * 502 * The runtime environment for NMIs is extremely restrictive 503 * (NMIs can pre-empt critical sections meaning almost all locking is 504 * forbidden) meaning this default FIQ handling must only be used in 505 * circumstances where non-maskability improves robustness, such as 506 * watchdog or debug logic. 507 * 508 * This handler is not appropriate for general purpose use in drivers 509 * platform code and can be overrideen using set_fiq_handler. 510 */ 511 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) 512 { 513 struct pt_regs *old_regs = set_irq_regs(regs); 514 515 nmi_enter(); 516 517 /* nop. FIQ handlers for special arch/arm features can be added here. */ 518 519 nmi_exit(); 520 521 set_irq_regs(old_regs); 522 } 523 524 /* 525 * bad_mode handles the impossible case in the vectors. If you see one of 526 * these, then it's extremely serious, and could mean you have buggy hardware. 527 * It never returns, and never tries to sync. We hope that we can at least 528 * dump out some state information... 529 */ 530 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 531 { 532 console_verbose(); 533 534 pr_crit("Bad mode in %s handler detected\n", handler[reason]); 535 536 die("Oops - bad mode", regs, 0); 537 local_irq_disable(); 538 panic("bad mode"); 539 } 540 541 static int bad_syscall(int n, struct pt_regs *regs) 542 { 543 if ((current->personality & PER_MASK) != PER_LINUX) { 544 send_sig(SIGSEGV, current, 1); 545 return regs->ARM_r0; 546 } 547 548 #ifdef CONFIG_DEBUG_USER 549 if (user_debug & UDBG_SYSCALL) { 550 pr_err("[%d] %s: obsolete system call %08x.\n", 551 task_pid_nr(current), current->comm, n); 552 dump_instr(KERN_ERR, regs); 553 } 554 #endif 555 556 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP, 557 (void __user *)instruction_pointer(regs) - 558 (thumb_mode(regs) ? 2 : 4), 559 n, 0); 560 561 return regs->ARM_r0; 562 } 563 564 static inline int 565 __do_cache_op(unsigned long start, unsigned long end) 566 { 567 int ret; 568 569 do { 570 unsigned long chunk = min(PAGE_SIZE, end - start); 571 572 if (fatal_signal_pending(current)) 573 return 0; 574 575 ret = flush_icache_user_range(start, start + chunk); 576 if (ret) 577 return ret; 578 579 cond_resched(); 580 start += chunk; 581 } while (start < end); 582 583 return 0; 584 } 585 586 static inline int 587 do_cache_op(unsigned long start, unsigned long end, int flags) 588 { 589 if (end < start || flags) 590 return -EINVAL; 591 592 if (!access_ok(start, end - start)) 593 return -EFAULT; 594 595 return __do_cache_op(start, end); 596 } 597 598 /* 599 * Handle all unrecognised system calls. 600 * 0x9f0000 - 0x9fffff are some more esoteric system calls 601 */ 602 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 603 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 604 { 605 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 606 return bad_syscall(no, regs); 607 608 switch (no & 0xffff) { 609 case 0: /* branch through 0 */ 610 arm_notify_die("branch through zero", regs, 611 SIGSEGV, SEGV_MAPERR, NULL, 0, 0); 612 return 0; 613 614 case NR(breakpoint): /* SWI BREAK_POINT */ 615 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 616 ptrace_break(regs); 617 return regs->ARM_r0; 618 619 /* 620 * Flush a region from virtual address 'r0' to virtual address 'r1' 621 * _exclusive_. There is no alignment requirement on either address; 622 * user space does not need to know the hardware cache layout. 623 * 624 * r2 contains flags. It should ALWAYS be passed as ZERO until it 625 * is defined to be something else. For now we ignore it, but may 626 * the fires of hell burn in your belly if you break this rule. ;) 627 * 628 * (at a later date, we may want to allow this call to not flush 629 * various aspects of the cache. Passing '0' will guarantee that 630 * everything necessary gets flushed to maintain consistency in 631 * the specified region). 632 */ 633 case NR(cacheflush): 634 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 635 636 case NR(usr26): 637 if (!(elf_hwcap & HWCAP_26BIT)) 638 break; 639 regs->ARM_cpsr &= ~MODE32_BIT; 640 return regs->ARM_r0; 641 642 case NR(usr32): 643 if (!(elf_hwcap & HWCAP_26BIT)) 644 break; 645 regs->ARM_cpsr |= MODE32_BIT; 646 return regs->ARM_r0; 647 648 case NR(set_tls): 649 set_tls(regs->ARM_r0); 650 return 0; 651 652 case NR(get_tls): 653 return current_thread_info()->tp_value[0]; 654 655 default: 656 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 657 if not implemented, rather than raising SIGILL. This 658 way the calling program can gracefully determine whether 659 a feature is supported. */ 660 if ((no & 0xffff) <= 0x7ff) 661 return -ENOSYS; 662 break; 663 } 664 #ifdef CONFIG_DEBUG_USER 665 /* 666 * experience shows that these seem to indicate that 667 * something catastrophic has happened 668 */ 669 if (user_debug & UDBG_SYSCALL) { 670 pr_err("[%d] %s: arm syscall %d\n", 671 task_pid_nr(current), current->comm, no); 672 dump_instr(KERN_ERR, regs); 673 if (user_mode(regs)) { 674 __show_regs(regs); 675 c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR); 676 } 677 } 678 #endif 679 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP, 680 (void __user *)instruction_pointer(regs) - 681 (thumb_mode(regs) ? 2 : 4), 682 no, 0); 683 return 0; 684 } 685 686 #ifdef CONFIG_TLS_REG_EMUL 687 688 /* 689 * We might be running on an ARMv6+ processor which should have the TLS 690 * register but for some reason we can't use it, or maybe an SMP system 691 * using a pre-ARMv6 processor (there are apparently a few prototypes like 692 * that in existence) and therefore access to that register must be 693 * emulated. 694 */ 695 696 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 697 { 698 int reg = (instr >> 12) & 15; 699 if (reg == 15) 700 return 1; 701 regs->uregs[reg] = current_thread_info()->tp_value[0]; 702 regs->ARM_pc += 4; 703 return 0; 704 } 705 706 static struct undef_hook arm_mrc_hook = { 707 .instr_mask = 0x0fff0fff, 708 .instr_val = 0x0e1d0f70, 709 .cpsr_mask = PSR_T_BIT, 710 .cpsr_val = 0, 711 .fn = get_tp_trap, 712 }; 713 714 static int __init arm_mrc_hook_init(void) 715 { 716 register_undef_hook(&arm_mrc_hook); 717 return 0; 718 } 719 720 late_initcall(arm_mrc_hook_init); 721 722 #endif 723 724 /* 725 * A data abort trap was taken, but we did not handle the instruction. 726 * Try to abort the user program, or panic if it was the kernel. 727 */ 728 asmlinkage void 729 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 730 { 731 unsigned long addr = instruction_pointer(regs); 732 733 #ifdef CONFIG_DEBUG_USER 734 if (user_debug & UDBG_BADABORT) { 735 pr_err("8<--- cut here ---\n"); 736 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", 737 task_pid_nr(current), current->comm, code, instr); 738 dump_instr(KERN_ERR, regs); 739 show_pte(KERN_ERR, current->mm, addr); 740 } 741 #endif 742 743 arm_notify_die("unknown data abort code", regs, 744 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0); 745 } 746 747 void __readwrite_bug(const char *fn) 748 { 749 pr_err("%s called, but not implemented\n", fn); 750 BUG(); 751 } 752 EXPORT_SYMBOL(__readwrite_bug); 753 754 void __pte_error(const char *file, int line, pte_t pte) 755 { 756 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 757 } 758 759 void __pmd_error(const char *file, int line, pmd_t pmd) 760 { 761 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 762 } 763 764 void __pgd_error(const char *file, int line, pgd_t pgd) 765 { 766 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 767 } 768 769 asmlinkage void __div0(void) 770 { 771 pr_err("Division by zero in kernel.\n"); 772 dump_stack(); 773 } 774 EXPORT_SYMBOL(__div0); 775 776 void abort(void) 777 { 778 BUG(); 779 780 /* if that doesn't kill us, halt */ 781 panic("Oops failed to kill thread"); 782 } 783 784 void __init trap_init(void) 785 { 786 return; 787 } 788 789 #ifdef CONFIG_KUSER_HELPERS 790 static void __init kuser_init(void *vectors) 791 { 792 extern char __kuser_helper_start[], __kuser_helper_end[]; 793 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 794 795 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 796 797 /* 798 * vectors + 0xfe0 = __kuser_get_tls 799 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 800 */ 801 if (tls_emu || has_tls_reg) 802 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); 803 } 804 #else 805 static inline void __init kuser_init(void *vectors) 806 { 807 } 808 #endif 809 810 void __init early_trap_init(void *vectors_base) 811 { 812 #ifndef CONFIG_CPU_V7M 813 unsigned long vectors = (unsigned long)vectors_base; 814 extern char __stubs_start[], __stubs_end[]; 815 extern char __vectors_start[], __vectors_end[]; 816 unsigned i; 817 818 vectors_page = vectors_base; 819 820 /* 821 * Poison the vectors page with an undefined instruction. This 822 * instruction is chosen to be undefined for both ARM and Thumb 823 * ISAs. The Thumb version is an undefined instruction with a 824 * branch back to the undefined instruction. 825 */ 826 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) 827 ((u32 *)vectors_base)[i] = 0xe7fddef1; 828 829 /* 830 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 831 * into the vector page, mapped at 0xffff0000, and ensure these 832 * are visible to the instruction stream. 833 */ 834 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 835 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); 836 837 kuser_init(vectors_base); 838 839 flush_icache_range(vectors, vectors + PAGE_SIZE * 2); 840 #else /* ifndef CONFIG_CPU_V7M */ 841 /* 842 * on V7-M there is no need to copy the vector table to a dedicated 843 * memory area. The address is configurable and so a table in the kernel 844 * image can be used. 845 */ 846 #endif 847 } 848