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/module.h> 23 #include <linux/kexec.h> 24 #include <linux/delay.h> 25 #include <linux/init.h> 26 #include <linux/sched.h> 27 28 #include <asm/atomic.h> 29 #include <asm/cacheflush.h> 30 #include <asm/system.h> 31 #include <asm/unistd.h> 32 #include <asm/traps.h> 33 #include <asm/unwind.h> 34 #include <asm/tls.h> 35 36 #include "signal.h" 37 38 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; 39 40 void *vectors_page; 41 42 #ifdef CONFIG_DEBUG_USER 43 unsigned int user_debug; 44 45 static int __init user_debug_setup(char *str) 46 { 47 get_option(&str, &user_debug); 48 return 1; 49 } 50 __setup("user_debug=", user_debug_setup); 51 #endif 52 53 static void dump_mem(const char *, const char *, unsigned long, unsigned long); 54 55 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) 56 { 57 #ifdef CONFIG_KALLSYMS 58 printk("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); 59 #else 60 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); 61 #endif 62 63 if (in_exception_text(where)) 64 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); 65 } 66 67 #ifndef CONFIG_ARM_UNWIND 68 /* 69 * Stack pointers should always be within the kernels view of 70 * physical memory. If it is not there, then we can't dump 71 * out any information relating to the stack. 72 */ 73 static int verify_stack(unsigned long sp) 74 { 75 if (sp < PAGE_OFFSET || 76 (sp > (unsigned long)high_memory && high_memory != NULL)) 77 return -EFAULT; 78 79 return 0; 80 } 81 #endif 82 83 /* 84 * Dump out the contents of some memory nicely... 85 */ 86 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 87 unsigned long top) 88 { 89 unsigned long first; 90 mm_segment_t fs; 91 int i; 92 93 /* 94 * We need to switch to kernel mode so that we can use __get_user 95 * to safely read from kernel space. Note that we now dump the 96 * code first, just in case the backtrace kills us. 97 */ 98 fs = get_fs(); 99 set_fs(KERNEL_DS); 100 101 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 102 103 for (first = bottom & ~31; first < top; first += 32) { 104 unsigned long p; 105 char str[sizeof(" 12345678") * 8 + 1]; 106 107 memset(str, ' ', sizeof(str)); 108 str[sizeof(str) - 1] = '\0'; 109 110 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 111 if (p >= bottom && p < top) { 112 unsigned long val; 113 if (__get_user(val, (unsigned long *)p) == 0) 114 sprintf(str + i * 9, " %08lx", val); 115 else 116 sprintf(str + i * 9, " ????????"); 117 } 118 } 119 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 120 } 121 122 set_fs(fs); 123 } 124 125 static void dump_instr(const char *lvl, struct pt_regs *regs) 126 { 127 unsigned long addr = instruction_pointer(regs); 128 const int thumb = thumb_mode(regs); 129 const int width = thumb ? 4 : 8; 130 mm_segment_t fs; 131 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 132 int i; 133 134 /* 135 * We need to switch to kernel mode so that we can use __get_user 136 * to safely read from kernel space. Note that we now dump the 137 * code first, just in case the backtrace kills us. 138 */ 139 fs = get_fs(); 140 set_fs(KERNEL_DS); 141 142 for (i = -4; i < 1 + !!thumb; i++) { 143 unsigned int val, bad; 144 145 if (thumb) 146 bad = __get_user(val, &((u16 *)addr)[i]); 147 else 148 bad = __get_user(val, &((u32 *)addr)[i]); 149 150 if (!bad) 151 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 152 width, val); 153 else { 154 p += sprintf(p, "bad PC value"); 155 break; 156 } 157 } 158 printk("%sCode: %s\n", lvl, str); 159 160 set_fs(fs); 161 } 162 163 #ifdef CONFIG_ARM_UNWIND 164 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 165 { 166 unwind_backtrace(regs, tsk); 167 } 168 #else 169 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 170 { 171 unsigned int fp, mode; 172 int ok = 1; 173 174 printk("Backtrace: "); 175 176 if (!tsk) 177 tsk = current; 178 179 if (regs) { 180 fp = regs->ARM_fp; 181 mode = processor_mode(regs); 182 } else if (tsk != current) { 183 fp = thread_saved_fp(tsk); 184 mode = 0x10; 185 } else { 186 asm("mov %0, fp" : "=r" (fp) : : "cc"); 187 mode = 0x10; 188 } 189 190 if (!fp) { 191 printk("no frame pointer"); 192 ok = 0; 193 } else if (verify_stack(fp)) { 194 printk("invalid frame pointer 0x%08x", fp); 195 ok = 0; 196 } else if (fp < (unsigned long)end_of_stack(tsk)) 197 printk("frame pointer underflow"); 198 printk("\n"); 199 200 if (ok) 201 c_backtrace(fp, mode); 202 } 203 #endif 204 205 void dump_stack(void) 206 { 207 dump_backtrace(NULL, NULL); 208 } 209 210 EXPORT_SYMBOL(dump_stack); 211 212 void show_stack(struct task_struct *tsk, unsigned long *sp) 213 { 214 dump_backtrace(NULL, tsk); 215 barrier(); 216 } 217 218 #ifdef CONFIG_PREEMPT 219 #define S_PREEMPT " PREEMPT" 220 #else 221 #define S_PREEMPT "" 222 #endif 223 #ifdef CONFIG_SMP 224 #define S_SMP " SMP" 225 #else 226 #define S_SMP "" 227 #endif 228 229 static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs) 230 { 231 struct task_struct *tsk = thread->task; 232 static int die_counter; 233 int ret; 234 235 printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", 236 str, err, ++die_counter); 237 238 /* trap and error numbers are mostly meaningless on ARM */ 239 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 240 if (ret == NOTIFY_STOP) 241 return ret; 242 243 print_modules(); 244 __show_regs(regs); 245 printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n", 246 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); 247 248 if (!user_mode(regs) || in_interrupt()) { 249 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 250 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 251 dump_backtrace(regs, tsk); 252 dump_instr(KERN_EMERG, regs); 253 } 254 255 return ret; 256 } 257 258 static DEFINE_SPINLOCK(die_lock); 259 260 /* 261 * This function is protected against re-entrancy. 262 */ 263 void die(const char *str, struct pt_regs *regs, int err) 264 { 265 struct thread_info *thread = current_thread_info(); 266 int ret; 267 268 oops_enter(); 269 270 spin_lock_irq(&die_lock); 271 console_verbose(); 272 bust_spinlocks(1); 273 ret = __die(str, err, thread, regs); 274 275 if (regs && kexec_should_crash(thread->task)) 276 crash_kexec(regs); 277 278 bust_spinlocks(0); 279 add_taint(TAINT_DIE); 280 spin_unlock_irq(&die_lock); 281 oops_exit(); 282 283 if (in_interrupt()) 284 panic("Fatal exception in interrupt"); 285 if (panic_on_oops) 286 panic("Fatal exception"); 287 if (ret != NOTIFY_STOP) 288 do_exit(SIGSEGV); 289 } 290 291 void arm_notify_die(const char *str, struct pt_regs *regs, 292 struct siginfo *info, unsigned long err, unsigned long trap) 293 { 294 if (user_mode(regs)) { 295 current->thread.error_code = err; 296 current->thread.trap_no = trap; 297 298 force_sig_info(info->si_signo, info, current); 299 } else { 300 die(str, regs, err); 301 } 302 } 303 304 static LIST_HEAD(undef_hook); 305 static DEFINE_SPINLOCK(undef_lock); 306 307 void register_undef_hook(struct undef_hook *hook) 308 { 309 unsigned long flags; 310 311 spin_lock_irqsave(&undef_lock, flags); 312 list_add(&hook->node, &undef_hook); 313 spin_unlock_irqrestore(&undef_lock, flags); 314 } 315 316 void unregister_undef_hook(struct undef_hook *hook) 317 { 318 unsigned long flags; 319 320 spin_lock_irqsave(&undef_lock, flags); 321 list_del(&hook->node); 322 spin_unlock_irqrestore(&undef_lock, flags); 323 } 324 325 static int call_undef_hook(struct pt_regs *regs, unsigned int instr) 326 { 327 struct undef_hook *hook; 328 unsigned long flags; 329 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 330 331 spin_lock_irqsave(&undef_lock, flags); 332 list_for_each_entry(hook, &undef_hook, node) 333 if ((instr & hook->instr_mask) == hook->instr_val && 334 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 335 fn = hook->fn; 336 spin_unlock_irqrestore(&undef_lock, flags); 337 338 return fn ? fn(regs, instr) : 1; 339 } 340 341 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 342 { 343 unsigned int correction = thumb_mode(regs) ? 2 : 4; 344 unsigned int instr; 345 siginfo_t info; 346 void __user *pc; 347 348 /* 349 * According to the ARM ARM, PC is 2 or 4 bytes ahead, 350 * depending whether we're in Thumb mode or not. 351 * Correct this offset. 352 */ 353 regs->ARM_pc -= correction; 354 355 pc = (void __user *)instruction_pointer(regs); 356 357 if (processor_mode(regs) == SVC_MODE) { 358 instr = *(u32 *) pc; 359 } else if (thumb_mode(regs)) { 360 get_user(instr, (u16 __user *)pc); 361 } else { 362 get_user(instr, (u32 __user *)pc); 363 } 364 365 if (call_undef_hook(regs, instr) == 0) 366 return; 367 368 #ifdef CONFIG_DEBUG_USER 369 if (user_debug & UDBG_UNDEFINED) { 370 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", 371 current->comm, task_pid_nr(current), pc); 372 dump_instr(KERN_INFO, regs); 373 } 374 #endif 375 376 info.si_signo = SIGILL; 377 info.si_errno = 0; 378 info.si_code = ILL_ILLOPC; 379 info.si_addr = pc; 380 381 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); 382 } 383 384 asmlinkage void do_unexp_fiq (struct pt_regs *regs) 385 { 386 printk("Hmm. Unexpected FIQ received, but trying to continue\n"); 387 printk("You may have a hardware problem...\n"); 388 } 389 390 /* 391 * bad_mode handles the impossible case in the vectors. If you see one of 392 * these, then it's extremely serious, and could mean you have buggy hardware. 393 * It never returns, and never tries to sync. We hope that we can at least 394 * dump out some state information... 395 */ 396 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 397 { 398 console_verbose(); 399 400 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]); 401 402 die("Oops - bad mode", regs, 0); 403 local_irq_disable(); 404 panic("bad mode"); 405 } 406 407 static int bad_syscall(int n, struct pt_regs *regs) 408 { 409 struct thread_info *thread = current_thread_info(); 410 siginfo_t info; 411 412 if ((current->personality & PER_MASK) != PER_LINUX && 413 thread->exec_domain->handler) { 414 thread->exec_domain->handler(n, regs); 415 return regs->ARM_r0; 416 } 417 418 #ifdef CONFIG_DEBUG_USER 419 if (user_debug & UDBG_SYSCALL) { 420 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n", 421 task_pid_nr(current), current->comm, n); 422 dump_instr(KERN_ERR, regs); 423 } 424 #endif 425 426 info.si_signo = SIGILL; 427 info.si_errno = 0; 428 info.si_code = ILL_ILLTRP; 429 info.si_addr = (void __user *)instruction_pointer(regs) - 430 (thumb_mode(regs) ? 2 : 4); 431 432 arm_notify_die("Oops - bad syscall", regs, &info, n, 0); 433 434 return regs->ARM_r0; 435 } 436 437 static inline void 438 do_cache_op(unsigned long start, unsigned long end, int flags) 439 { 440 struct mm_struct *mm = current->active_mm; 441 struct vm_area_struct *vma; 442 443 if (end < start || flags) 444 return; 445 446 down_read(&mm->mmap_sem); 447 vma = find_vma(mm, start); 448 if (vma && vma->vm_start < end) { 449 if (start < vma->vm_start) 450 start = vma->vm_start; 451 if (end > vma->vm_end) 452 end = vma->vm_end; 453 454 flush_cache_user_range(vma, start, end); 455 } 456 up_read(&mm->mmap_sem); 457 } 458 459 /* 460 * Handle all unrecognised system calls. 461 * 0x9f0000 - 0x9fffff are some more esoteric system calls 462 */ 463 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 464 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 465 { 466 struct thread_info *thread = current_thread_info(); 467 siginfo_t info; 468 469 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 470 return bad_syscall(no, regs); 471 472 switch (no & 0xffff) { 473 case 0: /* branch through 0 */ 474 info.si_signo = SIGSEGV; 475 info.si_errno = 0; 476 info.si_code = SEGV_MAPERR; 477 info.si_addr = NULL; 478 479 arm_notify_die("branch through zero", regs, &info, 0, 0); 480 return 0; 481 482 case NR(breakpoint): /* SWI BREAK_POINT */ 483 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 484 ptrace_break(current, regs); 485 return regs->ARM_r0; 486 487 /* 488 * Flush a region from virtual address 'r0' to virtual address 'r1' 489 * _exclusive_. There is no alignment requirement on either address; 490 * user space does not need to know the hardware cache layout. 491 * 492 * r2 contains flags. It should ALWAYS be passed as ZERO until it 493 * is defined to be something else. For now we ignore it, but may 494 * the fires of hell burn in your belly if you break this rule. ;) 495 * 496 * (at a later date, we may want to allow this call to not flush 497 * various aspects of the cache. Passing '0' will guarantee that 498 * everything necessary gets flushed to maintain consistency in 499 * the specified region). 500 */ 501 case NR(cacheflush): 502 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 503 return 0; 504 505 case NR(usr26): 506 if (!(elf_hwcap & HWCAP_26BIT)) 507 break; 508 regs->ARM_cpsr &= ~MODE32_BIT; 509 return regs->ARM_r0; 510 511 case NR(usr32): 512 if (!(elf_hwcap & HWCAP_26BIT)) 513 break; 514 regs->ARM_cpsr |= MODE32_BIT; 515 return regs->ARM_r0; 516 517 case NR(set_tls): 518 thread->tp_value = regs->ARM_r0; 519 if (tls_emu) 520 return 0; 521 if (has_tls_reg) { 522 asm ("mcr p15, 0, %0, c13, c0, 3" 523 : : "r" (regs->ARM_r0)); 524 } else { 525 /* 526 * User space must never try to access this directly. 527 * Expect your app to break eventually if you do so. 528 * The user helper at 0xffff0fe0 must be used instead. 529 * (see entry-armv.S for details) 530 */ 531 *((unsigned int *)0xffff0ff0) = regs->ARM_r0; 532 } 533 return 0; 534 535 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG 536 /* 537 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. 538 * Return zero in r0 if *MEM was changed or non-zero if no exchange 539 * happened. Also set the user C flag accordingly. 540 * If access permissions have to be fixed up then non-zero is 541 * returned and the operation has to be re-attempted. 542 * 543 * *NOTE*: This is a ghost syscall private to the kernel. Only the 544 * __kuser_cmpxchg code in entry-armv.S should be aware of its 545 * existence. Don't ever use this from user code. 546 */ 547 case NR(cmpxchg): 548 for (;;) { 549 extern void do_DataAbort(unsigned long addr, unsigned int fsr, 550 struct pt_regs *regs); 551 unsigned long val; 552 unsigned long addr = regs->ARM_r2; 553 struct mm_struct *mm = current->mm; 554 pgd_t *pgd; pmd_t *pmd; pte_t *pte; 555 spinlock_t *ptl; 556 557 regs->ARM_cpsr &= ~PSR_C_BIT; 558 down_read(&mm->mmap_sem); 559 pgd = pgd_offset(mm, addr); 560 if (!pgd_present(*pgd)) 561 goto bad_access; 562 pmd = pmd_offset(pgd, addr); 563 if (!pmd_present(*pmd)) 564 goto bad_access; 565 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 566 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) { 567 pte_unmap_unlock(pte, ptl); 568 goto bad_access; 569 } 570 val = *(unsigned long *)addr; 571 val -= regs->ARM_r0; 572 if (val == 0) { 573 *(unsigned long *)addr = regs->ARM_r1; 574 regs->ARM_cpsr |= PSR_C_BIT; 575 } 576 pte_unmap_unlock(pte, ptl); 577 up_read(&mm->mmap_sem); 578 return val; 579 580 bad_access: 581 up_read(&mm->mmap_sem); 582 /* simulate a write access fault */ 583 do_DataAbort(addr, 15 + (1 << 11), regs); 584 } 585 #endif 586 587 default: 588 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 589 if not implemented, rather than raising SIGILL. This 590 way the calling program can gracefully determine whether 591 a feature is supported. */ 592 if ((no & 0xffff) <= 0x7ff) 593 return -ENOSYS; 594 break; 595 } 596 #ifdef CONFIG_DEBUG_USER 597 /* 598 * experience shows that these seem to indicate that 599 * something catastrophic has happened 600 */ 601 if (user_debug & UDBG_SYSCALL) { 602 printk("[%d] %s: arm syscall %d\n", 603 task_pid_nr(current), current->comm, no); 604 dump_instr("", regs); 605 if (user_mode(regs)) { 606 __show_regs(regs); 607 c_backtrace(regs->ARM_fp, processor_mode(regs)); 608 } 609 } 610 #endif 611 info.si_signo = SIGILL; 612 info.si_errno = 0; 613 info.si_code = ILL_ILLTRP; 614 info.si_addr = (void __user *)instruction_pointer(regs) - 615 (thumb_mode(regs) ? 2 : 4); 616 617 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); 618 return 0; 619 } 620 621 #ifdef CONFIG_TLS_REG_EMUL 622 623 /* 624 * We might be running on an ARMv6+ processor which should have the TLS 625 * register but for some reason we can't use it, or maybe an SMP system 626 * using a pre-ARMv6 processor (there are apparently a few prototypes like 627 * that in existence) and therefore access to that register must be 628 * emulated. 629 */ 630 631 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 632 { 633 int reg = (instr >> 12) & 15; 634 if (reg == 15) 635 return 1; 636 regs->uregs[reg] = current_thread_info()->tp_value; 637 regs->ARM_pc += 4; 638 return 0; 639 } 640 641 static struct undef_hook arm_mrc_hook = { 642 .instr_mask = 0x0fff0fff, 643 .instr_val = 0x0e1d0f70, 644 .cpsr_mask = PSR_T_BIT, 645 .cpsr_val = 0, 646 .fn = get_tp_trap, 647 }; 648 649 static int __init arm_mrc_hook_init(void) 650 { 651 register_undef_hook(&arm_mrc_hook); 652 return 0; 653 } 654 655 late_initcall(arm_mrc_hook_init); 656 657 #endif 658 659 void __bad_xchg(volatile void *ptr, int size) 660 { 661 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", 662 __builtin_return_address(0), ptr, size); 663 BUG(); 664 } 665 EXPORT_SYMBOL(__bad_xchg); 666 667 /* 668 * A data abort trap was taken, but we did not handle the instruction. 669 * Try to abort the user program, or panic if it was the kernel. 670 */ 671 asmlinkage void 672 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 673 { 674 unsigned long addr = instruction_pointer(regs); 675 siginfo_t info; 676 677 #ifdef CONFIG_DEBUG_USER 678 if (user_debug & UDBG_BADABORT) { 679 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", 680 task_pid_nr(current), current->comm, code, instr); 681 dump_instr(KERN_ERR, regs); 682 show_pte(current->mm, addr); 683 } 684 #endif 685 686 info.si_signo = SIGILL; 687 info.si_errno = 0; 688 info.si_code = ILL_ILLOPC; 689 info.si_addr = (void __user *)addr; 690 691 arm_notify_die("unknown data abort code", regs, &info, instr, 0); 692 } 693 694 void __attribute__((noreturn)) __bug(const char *file, int line) 695 { 696 printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line); 697 *(int *)0 = 0; 698 699 /* Avoid "noreturn function does return" */ 700 for (;;); 701 } 702 EXPORT_SYMBOL(__bug); 703 704 void __readwrite_bug(const char *fn) 705 { 706 printk("%s called, but not implemented\n", fn); 707 BUG(); 708 } 709 EXPORT_SYMBOL(__readwrite_bug); 710 711 void __pte_error(const char *file, int line, pte_t pte) 712 { 713 printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 714 } 715 716 void __pmd_error(const char *file, int line, pmd_t pmd) 717 { 718 printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 719 } 720 721 void __pgd_error(const char *file, int line, pgd_t pgd) 722 { 723 printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 724 } 725 726 asmlinkage void __div0(void) 727 { 728 printk("Division by zero in kernel.\n"); 729 dump_stack(); 730 } 731 EXPORT_SYMBOL(__div0); 732 733 void abort(void) 734 { 735 BUG(); 736 737 /* if that doesn't kill us, halt */ 738 panic("Oops failed to kill thread"); 739 } 740 EXPORT_SYMBOL(abort); 741 742 void __init trap_init(void) 743 { 744 return; 745 } 746 747 static void __init kuser_get_tls_init(unsigned long vectors) 748 { 749 /* 750 * vectors + 0xfe0 = __kuser_get_tls 751 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 752 */ 753 if (tls_emu || has_tls_reg) 754 memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4); 755 } 756 757 void __init early_trap_init(void) 758 { 759 #if defined(CONFIG_CPU_USE_DOMAINS) 760 unsigned long vectors = CONFIG_VECTORS_BASE; 761 #else 762 unsigned long vectors = (unsigned long)vectors_page; 763 #endif 764 extern char __stubs_start[], __stubs_end[]; 765 extern char __vectors_start[], __vectors_end[]; 766 extern char __kuser_helper_start[], __kuser_helper_end[]; 767 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 768 769 /* 770 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 771 * into the vector page, mapped at 0xffff0000, and ensure these 772 * are visible to the instruction stream. 773 */ 774 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 775 memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start); 776 memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 777 778 /* 779 * Do processor specific fixups for the kuser helpers 780 */ 781 kuser_get_tls_init(vectors); 782 783 /* 784 * Copy signal return handlers into the vector page, and 785 * set sigreturn to be a pointer to these. 786 */ 787 memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE), 788 sigreturn_codes, sizeof(sigreturn_codes)); 789 memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE), 790 syscall_restart_code, sizeof(syscall_restart_code)); 791 792 flush_icache_range(vectors, vectors + PAGE_SIZE); 793 modify_domain(DOMAIN_USER, DOMAIN_CLIENT); 794 } 795