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 27 #include <asm/atomic.h> 28 #include <asm/cacheflush.h> 29 #include <asm/system.h> 30 #include <asm/unistd.h> 31 #include <asm/traps.h> 32 #include <asm/unwind.h> 33 #include <asm/tls.h> 34 35 #include "ptrace.h" 36 #include "signal.h" 37 38 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; 39 40 #ifdef CONFIG_DEBUG_USER 41 unsigned int user_debug; 42 43 static int __init user_debug_setup(char *str) 44 { 45 get_option(&str, &user_debug); 46 return 1; 47 } 48 __setup("user_debug=", user_debug_setup); 49 #endif 50 51 static void dump_mem(const char *, const char *, unsigned long, unsigned long); 52 53 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) 54 { 55 #ifdef CONFIG_KALLSYMS 56 char sym1[KSYM_SYMBOL_LEN], sym2[KSYM_SYMBOL_LEN]; 57 sprint_symbol(sym1, where); 58 sprint_symbol(sym2, from); 59 printk("[<%08lx>] (%s) from [<%08lx>] (%s)\n", where, sym1, from, sym2); 60 #else 61 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); 62 #endif 63 64 if (in_exception_text(where)) 65 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); 66 } 67 68 #ifndef CONFIG_ARM_UNWIND 69 /* 70 * Stack pointers should always be within the kernels view of 71 * physical memory. If it is not there, then we can't dump 72 * out any information relating to the stack. 73 */ 74 static int verify_stack(unsigned long sp) 75 { 76 if (sp < PAGE_OFFSET || 77 (sp > (unsigned long)high_memory && high_memory != NULL)) 78 return -EFAULT; 79 80 return 0; 81 } 82 #endif 83 84 /* 85 * Dump out the contents of some memory nicely... 86 */ 87 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 88 unsigned long top) 89 { 90 unsigned long first; 91 mm_segment_t fs; 92 int i; 93 94 /* 95 * We need to switch to kernel mode so that we can use __get_user 96 * to safely read from kernel space. Note that we now dump the 97 * code first, just in case the backtrace kills us. 98 */ 99 fs = get_fs(); 100 set_fs(KERNEL_DS); 101 102 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 103 104 for (first = bottom & ~31; first < top; first += 32) { 105 unsigned long p; 106 char str[sizeof(" 12345678") * 8 + 1]; 107 108 memset(str, ' ', sizeof(str)); 109 str[sizeof(str) - 1] = '\0'; 110 111 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 112 if (p >= bottom && p < top) { 113 unsigned long val; 114 if (__get_user(val, (unsigned long *)p) == 0) 115 sprintf(str + i * 9, " %08lx", val); 116 else 117 sprintf(str + i * 9, " ????????"); 118 } 119 } 120 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 121 } 122 123 set_fs(fs); 124 } 125 126 static void dump_instr(const char *lvl, struct pt_regs *regs) 127 { 128 unsigned long addr = instruction_pointer(regs); 129 const int thumb = thumb_mode(regs); 130 const int width = thumb ? 4 : 8; 131 mm_segment_t fs; 132 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 133 int i; 134 135 /* 136 * We need to switch to kernel mode so that we can use __get_user 137 * to safely read from kernel space. Note that we now dump the 138 * code first, just in case the backtrace kills us. 139 */ 140 fs = get_fs(); 141 set_fs(KERNEL_DS); 142 143 for (i = -4; i < 1; i++) { 144 unsigned int val, bad; 145 146 if (thumb) 147 bad = __get_user(val, &((u16 *)addr)[i]); 148 else 149 bad = __get_user(val, &((u32 *)addr)[i]); 150 151 if (!bad) 152 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 153 width, val); 154 else { 155 p += sprintf(p, "bad PC value"); 156 break; 157 } 158 } 159 printk("%sCode: %s\n", lvl, str); 160 161 set_fs(fs); 162 } 163 164 #ifdef CONFIG_ARM_UNWIND 165 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 166 { 167 unwind_backtrace(regs, tsk); 168 } 169 #else 170 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 171 { 172 unsigned int fp, mode; 173 int ok = 1; 174 175 printk("Backtrace: "); 176 177 if (!tsk) 178 tsk = current; 179 180 if (regs) { 181 fp = regs->ARM_fp; 182 mode = processor_mode(regs); 183 } else if (tsk != current) { 184 fp = thread_saved_fp(tsk); 185 mode = 0x10; 186 } else { 187 asm("mov %0, fp" : "=r" (fp) : : "cc"); 188 mode = 0x10; 189 } 190 191 if (!fp) { 192 printk("no frame pointer"); 193 ok = 0; 194 } else if (verify_stack(fp)) { 195 printk("invalid frame pointer 0x%08x", fp); 196 ok = 0; 197 } else if (fp < (unsigned long)end_of_stack(tsk)) 198 printk("frame pointer underflow"); 199 printk("\n"); 200 201 if (ok) 202 c_backtrace(fp, mode); 203 } 204 #endif 205 206 void dump_stack(void) 207 { 208 dump_backtrace(NULL, NULL); 209 } 210 211 EXPORT_SYMBOL(dump_stack); 212 213 void show_stack(struct task_struct *tsk, unsigned long *sp) 214 { 215 dump_backtrace(NULL, tsk); 216 barrier(); 217 } 218 219 #ifdef CONFIG_PREEMPT 220 #define S_PREEMPT " PREEMPT" 221 #else 222 #define S_PREEMPT "" 223 #endif 224 #ifdef CONFIG_SMP 225 #define S_SMP " SMP" 226 #else 227 #define S_SMP "" 228 #endif 229 230 static int __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs) 231 { 232 struct task_struct *tsk = thread->task; 233 static int die_counter; 234 int ret; 235 236 printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", 237 str, err, ++die_counter); 238 sysfs_printk_last_file(); 239 240 /* trap and error numbers are mostly meaningless on ARM */ 241 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 242 if (ret == NOTIFY_STOP) 243 return ret; 244 245 print_modules(); 246 __show_regs(regs); 247 printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n", 248 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); 249 250 if (!user_mode(regs) || in_interrupt()) { 251 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 252 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 253 dump_backtrace(regs, tsk); 254 dump_instr(KERN_EMERG, regs); 255 } 256 257 return ret; 258 } 259 260 DEFINE_SPINLOCK(die_lock); 261 262 /* 263 * This function is protected against re-entrancy. 264 */ 265 void die(const char *str, struct pt_regs *regs, int err) 266 { 267 struct thread_info *thread = current_thread_info(); 268 int ret; 269 270 oops_enter(); 271 272 spin_lock_irq(&die_lock); 273 console_verbose(); 274 bust_spinlocks(1); 275 ret = __die(str, err, thread, regs); 276 277 if (regs && kexec_should_crash(thread->task)) 278 crash_kexec(regs); 279 280 bust_spinlocks(0); 281 add_taint(TAINT_DIE); 282 spin_unlock_irq(&die_lock); 283 oops_exit(); 284 285 if (in_interrupt()) 286 panic("Fatal exception in interrupt"); 287 if (panic_on_oops) 288 panic("Fatal exception"); 289 if (ret != NOTIFY_STOP) 290 do_exit(SIGSEGV); 291 } 292 293 void arm_notify_die(const char *str, struct pt_regs *regs, 294 struct siginfo *info, unsigned long err, unsigned long trap) 295 { 296 if (user_mode(regs)) { 297 current->thread.error_code = err; 298 current->thread.trap_no = trap; 299 300 force_sig_info(info->si_signo, info, current); 301 } else { 302 die(str, regs, err); 303 } 304 } 305 306 static LIST_HEAD(undef_hook); 307 static DEFINE_SPINLOCK(undef_lock); 308 309 void register_undef_hook(struct undef_hook *hook) 310 { 311 unsigned long flags; 312 313 spin_lock_irqsave(&undef_lock, flags); 314 list_add(&hook->node, &undef_hook); 315 spin_unlock_irqrestore(&undef_lock, flags); 316 } 317 318 void unregister_undef_hook(struct undef_hook *hook) 319 { 320 unsigned long flags; 321 322 spin_lock_irqsave(&undef_lock, flags); 323 list_del(&hook->node); 324 spin_unlock_irqrestore(&undef_lock, flags); 325 } 326 327 static int call_undef_hook(struct pt_regs *regs, unsigned int instr) 328 { 329 struct undef_hook *hook; 330 unsigned long flags; 331 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 332 333 spin_lock_irqsave(&undef_lock, flags); 334 list_for_each_entry(hook, &undef_hook, node) 335 if ((instr & hook->instr_mask) == hook->instr_val && 336 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 337 fn = hook->fn; 338 spin_unlock_irqrestore(&undef_lock, flags); 339 340 return fn ? fn(regs, instr) : 1; 341 } 342 343 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 344 { 345 unsigned int correction = thumb_mode(regs) ? 2 : 4; 346 unsigned int instr; 347 siginfo_t info; 348 void __user *pc; 349 350 /* 351 * According to the ARM ARM, PC is 2 or 4 bytes ahead, 352 * depending whether we're in Thumb mode or not. 353 * Correct this offset. 354 */ 355 regs->ARM_pc -= correction; 356 357 pc = (void __user *)instruction_pointer(regs); 358 359 if (processor_mode(regs) == SVC_MODE) { 360 instr = *(u32 *) pc; 361 } else if (thumb_mode(regs)) { 362 get_user(instr, (u16 __user *)pc); 363 } else { 364 get_user(instr, (u32 __user *)pc); 365 } 366 367 if (call_undef_hook(regs, instr) == 0) 368 return; 369 370 #ifdef CONFIG_DEBUG_USER 371 if (user_debug & UDBG_UNDEFINED) { 372 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", 373 current->comm, task_pid_nr(current), pc); 374 dump_instr(KERN_INFO, regs); 375 } 376 #endif 377 378 info.si_signo = SIGILL; 379 info.si_errno = 0; 380 info.si_code = ILL_ILLOPC; 381 info.si_addr = pc; 382 383 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); 384 } 385 386 asmlinkage void do_unexp_fiq (struct pt_regs *regs) 387 { 388 printk("Hmm. Unexpected FIQ received, but trying to continue\n"); 389 printk("You may have a hardware problem...\n"); 390 } 391 392 /* 393 * bad_mode handles the impossible case in the vectors. If you see one of 394 * these, then it's extremely serious, and could mean you have buggy hardware. 395 * It never returns, and never tries to sync. We hope that we can at least 396 * dump out some state information... 397 */ 398 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 399 { 400 console_verbose(); 401 402 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]); 403 404 die("Oops - bad mode", regs, 0); 405 local_irq_disable(); 406 panic("bad mode"); 407 } 408 409 static int bad_syscall(int n, struct pt_regs *regs) 410 { 411 struct thread_info *thread = current_thread_info(); 412 siginfo_t info; 413 414 if (current->personality != PER_LINUX && 415 current->personality != PER_LINUX_32BIT && 416 thread->exec_domain->handler) { 417 thread->exec_domain->handler(n, regs); 418 return regs->ARM_r0; 419 } 420 421 #ifdef CONFIG_DEBUG_USER 422 if (user_debug & UDBG_SYSCALL) { 423 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n", 424 task_pid_nr(current), current->comm, n); 425 dump_instr(KERN_ERR, regs); 426 } 427 #endif 428 429 info.si_signo = SIGILL; 430 info.si_errno = 0; 431 info.si_code = ILL_ILLTRP; 432 info.si_addr = (void __user *)instruction_pointer(regs) - 433 (thumb_mode(regs) ? 2 : 4); 434 435 arm_notify_die("Oops - bad syscall", regs, &info, n, 0); 436 437 return regs->ARM_r0; 438 } 439 440 static inline void 441 do_cache_op(unsigned long start, unsigned long end, int flags) 442 { 443 struct mm_struct *mm = current->active_mm; 444 struct vm_area_struct *vma; 445 446 if (end < start || flags) 447 return; 448 449 down_read(&mm->mmap_sem); 450 vma = find_vma(mm, start); 451 if (vma && vma->vm_start < end) { 452 if (start < vma->vm_start) 453 start = vma->vm_start; 454 if (end > vma->vm_end) 455 end = vma->vm_end; 456 457 flush_cache_user_range(vma, start, end); 458 } 459 up_read(&mm->mmap_sem); 460 } 461 462 /* 463 * Handle all unrecognised system calls. 464 * 0x9f0000 - 0x9fffff are some more esoteric system calls 465 */ 466 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 467 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 468 { 469 struct thread_info *thread = current_thread_info(); 470 siginfo_t info; 471 472 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 473 return bad_syscall(no, regs); 474 475 switch (no & 0xffff) { 476 case 0: /* branch through 0 */ 477 info.si_signo = SIGSEGV; 478 info.si_errno = 0; 479 info.si_code = SEGV_MAPERR; 480 info.si_addr = NULL; 481 482 arm_notify_die("branch through zero", regs, &info, 0, 0); 483 return 0; 484 485 case NR(breakpoint): /* SWI BREAK_POINT */ 486 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 487 ptrace_break(current, regs); 488 return regs->ARM_r0; 489 490 /* 491 * Flush a region from virtual address 'r0' to virtual address 'r1' 492 * _exclusive_. There is no alignment requirement on either address; 493 * user space does not need to know the hardware cache layout. 494 * 495 * r2 contains flags. It should ALWAYS be passed as ZERO until it 496 * is defined to be something else. For now we ignore it, but may 497 * the fires of hell burn in your belly if you break this rule. ;) 498 * 499 * (at a later date, we may want to allow this call to not flush 500 * various aspects of the cache. Passing '0' will guarantee that 501 * everything necessary gets flushed to maintain consistency in 502 * the specified region). 503 */ 504 case NR(cacheflush): 505 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 506 return 0; 507 508 case NR(usr26): 509 if (!(elf_hwcap & HWCAP_26BIT)) 510 break; 511 regs->ARM_cpsr &= ~MODE32_BIT; 512 return regs->ARM_r0; 513 514 case NR(usr32): 515 if (!(elf_hwcap & HWCAP_26BIT)) 516 break; 517 regs->ARM_cpsr |= MODE32_BIT; 518 return regs->ARM_r0; 519 520 case NR(set_tls): 521 thread->tp_value = regs->ARM_r0; 522 if (tls_emu) 523 return 0; 524 if (has_tls_reg) { 525 asm ("mcr p15, 0, %0, c13, c0, 3" 526 : : "r" (regs->ARM_r0)); 527 } else { 528 /* 529 * User space must never try to access this directly. 530 * Expect your app to break eventually if you do so. 531 * The user helper at 0xffff0fe0 must be used instead. 532 * (see entry-armv.S for details) 533 */ 534 *((unsigned int *)0xffff0ff0) = regs->ARM_r0; 535 } 536 return 0; 537 538 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG 539 /* 540 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. 541 * Return zero in r0 if *MEM was changed or non-zero if no exchange 542 * happened. Also set the user C flag accordingly. 543 * If access permissions have to be fixed up then non-zero is 544 * returned and the operation has to be re-attempted. 545 * 546 * *NOTE*: This is a ghost syscall private to the kernel. Only the 547 * __kuser_cmpxchg code in entry-armv.S should be aware of its 548 * existence. Don't ever use this from user code. 549 */ 550 case NR(cmpxchg): 551 for (;;) { 552 extern void do_DataAbort(unsigned long addr, unsigned int fsr, 553 struct pt_regs *regs); 554 unsigned long val; 555 unsigned long addr = regs->ARM_r2; 556 struct mm_struct *mm = current->mm; 557 pgd_t *pgd; pmd_t *pmd; pte_t *pte; 558 spinlock_t *ptl; 559 560 regs->ARM_cpsr &= ~PSR_C_BIT; 561 down_read(&mm->mmap_sem); 562 pgd = pgd_offset(mm, addr); 563 if (!pgd_present(*pgd)) 564 goto bad_access; 565 pmd = pmd_offset(pgd, addr); 566 if (!pmd_present(*pmd)) 567 goto bad_access; 568 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 569 if (!pte_present(*pte) || !pte_dirty(*pte)) { 570 pte_unmap_unlock(pte, ptl); 571 goto bad_access; 572 } 573 val = *(unsigned long *)addr; 574 val -= regs->ARM_r0; 575 if (val == 0) { 576 *(unsigned long *)addr = regs->ARM_r1; 577 regs->ARM_cpsr |= PSR_C_BIT; 578 } 579 pte_unmap_unlock(pte, ptl); 580 up_read(&mm->mmap_sem); 581 return val; 582 583 bad_access: 584 up_read(&mm->mmap_sem); 585 /* simulate a write access fault */ 586 do_DataAbort(addr, 15 + (1 << 11), regs); 587 } 588 #endif 589 590 default: 591 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 592 if not implemented, rather than raising SIGILL. This 593 way the calling program can gracefully determine whether 594 a feature is supported. */ 595 if ((no & 0xffff) <= 0x7ff) 596 return -ENOSYS; 597 break; 598 } 599 #ifdef CONFIG_DEBUG_USER 600 /* 601 * experience shows that these seem to indicate that 602 * something catastrophic has happened 603 */ 604 if (user_debug & UDBG_SYSCALL) { 605 printk("[%d] %s: arm syscall %d\n", 606 task_pid_nr(current), current->comm, no); 607 dump_instr("", regs); 608 if (user_mode(regs)) { 609 __show_regs(regs); 610 c_backtrace(regs->ARM_fp, processor_mode(regs)); 611 } 612 } 613 #endif 614 info.si_signo = SIGILL; 615 info.si_errno = 0; 616 info.si_code = ILL_ILLTRP; 617 info.si_addr = (void __user *)instruction_pointer(regs) - 618 (thumb_mode(regs) ? 2 : 4); 619 620 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); 621 return 0; 622 } 623 624 #ifdef CONFIG_TLS_REG_EMUL 625 626 /* 627 * We might be running on an ARMv6+ processor which should have the TLS 628 * register but for some reason we can't use it, or maybe an SMP system 629 * using a pre-ARMv6 processor (there are apparently a few prototypes like 630 * that in existence) and therefore access to that register must be 631 * emulated. 632 */ 633 634 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 635 { 636 int reg = (instr >> 12) & 15; 637 if (reg == 15) 638 return 1; 639 regs->uregs[reg] = current_thread_info()->tp_value; 640 regs->ARM_pc += 4; 641 return 0; 642 } 643 644 static struct undef_hook arm_mrc_hook = { 645 .instr_mask = 0x0fff0fff, 646 .instr_val = 0x0e1d0f70, 647 .cpsr_mask = PSR_T_BIT, 648 .cpsr_val = 0, 649 .fn = get_tp_trap, 650 }; 651 652 static int __init arm_mrc_hook_init(void) 653 { 654 register_undef_hook(&arm_mrc_hook); 655 return 0; 656 } 657 658 late_initcall(arm_mrc_hook_init); 659 660 #endif 661 662 void __bad_xchg(volatile void *ptr, int size) 663 { 664 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", 665 __builtin_return_address(0), ptr, size); 666 BUG(); 667 } 668 EXPORT_SYMBOL(__bad_xchg); 669 670 /* 671 * A data abort trap was taken, but we did not handle the instruction. 672 * Try to abort the user program, or panic if it was the kernel. 673 */ 674 asmlinkage void 675 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 676 { 677 unsigned long addr = instruction_pointer(regs); 678 siginfo_t info; 679 680 #ifdef CONFIG_DEBUG_USER 681 if (user_debug & UDBG_BADABORT) { 682 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", 683 task_pid_nr(current), current->comm, code, instr); 684 dump_instr(KERN_ERR, regs); 685 show_pte(current->mm, addr); 686 } 687 #endif 688 689 info.si_signo = SIGILL; 690 info.si_errno = 0; 691 info.si_code = ILL_ILLOPC; 692 info.si_addr = (void __user *)addr; 693 694 arm_notify_die("unknown data abort code", regs, &info, instr, 0); 695 } 696 697 void __attribute__((noreturn)) __bug(const char *file, int line) 698 { 699 printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line); 700 *(int *)0 = 0; 701 702 /* Avoid "noreturn function does return" */ 703 for (;;); 704 } 705 EXPORT_SYMBOL(__bug); 706 707 void __readwrite_bug(const char *fn) 708 { 709 printk("%s called, but not implemented\n", fn); 710 BUG(); 711 } 712 EXPORT_SYMBOL(__readwrite_bug); 713 714 void __pte_error(const char *file, int line, unsigned long val) 715 { 716 printk("%s:%d: bad pte %08lx.\n", file, line, val); 717 } 718 719 void __pmd_error(const char *file, int line, unsigned long val) 720 { 721 printk("%s:%d: bad pmd %08lx.\n", file, line, val); 722 } 723 724 void __pgd_error(const char *file, int line, unsigned long val) 725 { 726 printk("%s:%d: bad pgd %08lx.\n", file, line, val); 727 } 728 729 asmlinkage void __div0(void) 730 { 731 printk("Division by zero in kernel.\n"); 732 dump_stack(); 733 } 734 EXPORT_SYMBOL(__div0); 735 736 void abort(void) 737 { 738 BUG(); 739 740 /* if that doesn't kill us, halt */ 741 panic("Oops failed to kill thread"); 742 } 743 EXPORT_SYMBOL(abort); 744 745 void __init trap_init(void) 746 { 747 return; 748 } 749 750 static void __init kuser_get_tls_init(unsigned long vectors) 751 { 752 /* 753 * vectors + 0xfe0 = __kuser_get_tls 754 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 755 */ 756 if (tls_emu || has_tls_reg) 757 memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4); 758 } 759 760 void __init early_trap_init(void) 761 { 762 unsigned long vectors = CONFIG_VECTORS_BASE; 763 extern char __stubs_start[], __stubs_end[]; 764 extern char __vectors_start[], __vectors_end[]; 765 extern char __kuser_helper_start[], __kuser_helper_end[]; 766 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 767 768 /* 769 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 770 * into the vector page, mapped at 0xffff0000, and ensure these 771 * are visible to the instruction stream. 772 */ 773 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 774 memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start); 775 memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 776 777 /* 778 * Do processor specific fixups for the kuser helpers 779 */ 780 kuser_get_tls_init(vectors); 781 782 /* 783 * Copy signal return handlers into the vector page, and 784 * set sigreturn to be a pointer to these. 785 */ 786 memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes, 787 sizeof(sigreturn_codes)); 788 memcpy((void *)KERN_RESTART_CODE, syscall_restart_code, 789 sizeof(syscall_restart_code)); 790 791 flush_icache_range(vectors, vectors + PAGE_SIZE); 792 modify_domain(DOMAIN_USER, DOMAIN_CLIENT); 793 } 794