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 38static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; 39 40#ifdef CONFIG_DEBUG_USER 41unsigned int user_debug; 42 43static 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 51static void dump_mem(const char *, const char *, unsigned long, unsigned long); 52 53void 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 */ 74static 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 */ 87static 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 126static 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 165static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 166{ 167 unwind_backtrace(regs, tsk); 168} 169#else 170static 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 206void dump_stack(void) 207{ 208 dump_backtrace(NULL, NULL); 209} 210 211EXPORT_SYMBOL(dump_stack); 212 213void 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 230static 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)); 253 254 /* Show PC value again for GDB source code trace dump */ 255 printk("[<%08lx>] ",regs->ARM_pc); 256 print_symbol("(PC is at %s)\n", instruction_pointer(regs)); 257 258 dump_backtrace(regs, tsk); 259 dump_instr(KERN_EMERG, regs); 260 } 261 262 return ret; 263} 264 265DEFINE_SPINLOCK(die_lock); 266 267/* 268 * This function is protected against re-entrancy. 269 */ 270void die(const char *str, struct pt_regs *regs, int err) 271{ 272 struct thread_info *thread = current_thread_info(); 273 int ret; 274 275 oops_enter(); 276 277 spin_lock_irq(&die_lock); 278 console_verbose(); 279 bust_spinlocks(1); 280 ret = __die(str, err, thread, regs); 281 282 if (regs && kexec_should_crash(thread->task)) 283 crash_kexec(regs); 284 285 bust_spinlocks(0); 286 add_taint(TAINT_DIE); 287 spin_unlock_irq(&die_lock); 288 oops_exit(); 289 if (in_interrupt()) 290 panic("Fatal exception in interrupt"); 291 if (panic_on_oops) 292 panic("Fatal exception"); 293 if (ret != NOTIFY_STOP) 294 do_exit(SIGSEGV); 295} 296 297void arm_notify_die(const char *str, struct pt_regs *regs, 298 struct siginfo *info, unsigned long err, unsigned long trap) 299{ 300 if (user_mode(regs)) { 301 current->thread.error_code = err; 302 current->thread.trap_no = trap; 303 304 force_sig_info(info->si_signo, info, current); 305 } else { 306 die(str, regs, err); 307 } 308} 309 310static LIST_HEAD(undef_hook); 311static DEFINE_SPINLOCK(undef_lock); 312 313void register_undef_hook(struct undef_hook *hook) 314{ 315 unsigned long flags; 316 317 spin_lock_irqsave(&undef_lock, flags); 318 list_add(&hook->node, &undef_hook); 319 spin_unlock_irqrestore(&undef_lock, flags); 320} 321 322void unregister_undef_hook(struct undef_hook *hook) 323{ 324 unsigned long flags; 325 326 spin_lock_irqsave(&undef_lock, flags); 327 list_del(&hook->node); 328 spin_unlock_irqrestore(&undef_lock, flags); 329} 330 331static int call_undef_hook(struct pt_regs *regs, unsigned int instr) 332{ 333 struct undef_hook *hook; 334 unsigned long flags; 335 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 336 337 spin_lock_irqsave(&undef_lock, flags); 338 list_for_each_entry(hook, &undef_hook, node) 339 if ((instr & hook->instr_mask) == hook->instr_val && 340 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 341 fn = hook->fn; 342 spin_unlock_irqrestore(&undef_lock, flags); 343 344 return fn ? fn(regs, instr) : 1; 345} 346 347asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 348{ 349 unsigned int correction = thumb_mode(regs) ? 2 : 4; 350 unsigned int instr; 351 siginfo_t info; 352 void __user *pc; 353 354 /* 355 * According to the ARM ARM, PC is 2 or 4 bytes ahead, 356 * depending whether we're in Thumb mode or not. 357 * Correct this offset. 358 */ 359 regs->ARM_pc -= correction; 360 361 pc = (void __user *)instruction_pointer(regs); 362 363 if (processor_mode(regs) == SVC_MODE) { 364 instr = *(u32 *) pc; 365 } else if (thumb_mode(regs)) { 366 get_user(instr, (u16 __user *)pc); 367 } else { 368 get_user(instr, (u32 __user *)pc); 369 } 370 371 if (call_undef_hook(regs, instr) == 0) 372 return; 373 374#ifdef CONFIG_DEBUG_USER 375 if (user_debug & UDBG_UNDEFINED) { 376 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", 377 current->comm, task_pid_nr(current), pc); 378 dump_instr(KERN_INFO, regs); 379 } 380#endif 381 382 info.si_signo = SIGILL; 383 info.si_errno = 0; 384 info.si_code = ILL_ILLOPC; 385 info.si_addr = pc; 386 387 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); 388} 389 390asmlinkage void do_unexp_fiq (struct pt_regs *regs) 391{ 392 printk("Hmm. Unexpected FIQ received, but trying to continue\n"); 393 printk("You may have a hardware problem...\n"); 394} 395 396/* 397 * bad_mode handles the impossible case in the vectors. If you see one of 398 * these, then it's extremely serious, and could mean you have buggy hardware. 399 * It never returns, and never tries to sync. We hope that we can at least 400 * dump out some state information... 401 */ 402asmlinkage void bad_mode(struct pt_regs *regs, int reason) 403{ 404 console_verbose(); 405 406 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]); 407 408 die("Oops - bad mode", regs, 0); 409 local_irq_disable(); 410 panic("bad mode"); 411} 412 413static int bad_syscall(int n, struct pt_regs *regs) 414{ 415 struct thread_info *thread = current_thread_info(); 416 siginfo_t info; 417 418 if (current->personality != PER_LINUX && 419 current->personality != PER_LINUX_32BIT && 420 thread->exec_domain->handler) { 421 thread->exec_domain->handler(n, regs); 422 return regs->ARM_r0; 423 } 424 425#ifdef CONFIG_DEBUG_USER 426 if (user_debug & UDBG_SYSCALL) { 427 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n", 428 task_pid_nr(current), current->comm, n); 429 dump_instr(KERN_ERR, regs); 430 } 431#endif 432 433 info.si_signo = SIGILL; 434 info.si_errno = 0; 435 info.si_code = ILL_ILLTRP; 436 info.si_addr = (void __user *)instruction_pointer(regs) - 437 (thumb_mode(regs) ? 2 : 4); 438 439 arm_notify_die("Oops - bad syscall", regs, &info, n, 0); 440 441 return regs->ARM_r0; 442} 443 444static inline void 445do_cache_op(unsigned long start, unsigned long end, int flags) 446{ 447 struct mm_struct *mm = current->active_mm; 448 struct vm_area_struct *vma; 449 450 if (end < start || flags) 451 return; 452 453 down_read(&mm->mmap_sem); 454 vma = find_vma(mm, start); 455 if (vma && vma->vm_start < end) { 456 if (start < vma->vm_start) 457 start = vma->vm_start; 458 if (end > vma->vm_end) 459 end = vma->vm_end; 460 461 flush_cache_user_range(vma, start, end); 462 } 463 up_read(&mm->mmap_sem); 464} 465 466/* 467 * Handle all unrecognised system calls. 468 * 0x9f0000 - 0x9fffff are some more esoteric system calls 469 */ 470#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 471asmlinkage int arm_syscall(int no, struct pt_regs *regs) 472{ 473 struct thread_info *thread = current_thread_info(); 474 siginfo_t info; 475 476 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 477 return bad_syscall(no, regs); 478 479 switch (no & 0xffff) { 480 case 0: /* branch through 0 */ 481 info.si_signo = SIGSEGV; 482 info.si_errno = 0; 483 info.si_code = SEGV_MAPERR; 484 info.si_addr = NULL; 485 486 arm_notify_die("branch through zero", regs, &info, 0, 0); 487 return 0; 488 489 case NR(breakpoint): /* SWI BREAK_POINT */ 490 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 491 ptrace_break(current, regs); 492 return regs->ARM_r0; 493 494 /* 495 * Flush a region from virtual address 'r0' to virtual address 'r1' 496 * _exclusive_. There is no alignment requirement on either address; 497 * user space does not need to know the hardware cache layout. 498 * 499 * r2 contains flags. It should ALWAYS be passed as ZERO until it 500 * is defined to be something else. For now we ignore it, but may 501 * the fires of hell burn in your belly if you break this rule. ;) 502 * 503 * (at a later date, we may want to allow this call to not flush 504 * various aspects of the cache. Passing '0' will guarantee that 505 * everything necessary gets flushed to maintain consistency in 506 * the specified region). 507 */ 508 case NR(cacheflush): 509 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 510 return 0; 511 512 case NR(usr26): 513 if (!(elf_hwcap & HWCAP_26BIT)) 514 break; 515 regs->ARM_cpsr &= ~MODE32_BIT; 516 return regs->ARM_r0; 517 518 case NR(usr32): 519 if (!(elf_hwcap & HWCAP_26BIT)) 520 break; 521 regs->ARM_cpsr |= MODE32_BIT; 522 return regs->ARM_r0; 523 524 case NR(set_tls): 525 thread->tp_value = regs->ARM_r0; 526 if (tls_emu) 527 return 0; 528 if (has_tls_reg) { 529 asm ("mcr p15, 0, %0, c13, c0, 3" 530 : : "r" (regs->ARM_r0)); 531 } else { 532 /* 533 * User space must never try to access this directly. 534 * Expect your app to break eventually if you do so. 535 * The user helper at 0xffff0fe0 must be used instead. 536 * (see entry-armv.S for details) 537 */ 538 *((unsigned int *)0xffff0ff0) = regs->ARM_r0; 539 } 540 return 0; 541 542#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG 543 /* 544 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. 545 * Return zero in r0 if *MEM was changed or non-zero if no exchange 546 * happened. Also set the user C flag accordingly. 547 * If access permissions have to be fixed up then non-zero is 548 * returned and the operation has to be re-attempted. 549 * 550 * *NOTE*: This is a ghost syscall private to the kernel. Only the 551 * __kuser_cmpxchg code in entry-armv.S should be aware of its 552 * existence. Don't ever use this from user code. 553 */ 554 case NR(cmpxchg): 555 for (;;) { 556 extern void do_DataAbort(unsigned long addr, unsigned int fsr, 557 struct pt_regs *regs); 558 unsigned long val; 559 unsigned long addr = regs->ARM_r2; 560 struct mm_struct *mm = current->mm; 561 pgd_t *pgd; pmd_t *pmd; pte_t *pte; 562 spinlock_t *ptl; 563 564 regs->ARM_cpsr &= ~PSR_C_BIT; 565 down_read(&mm->mmap_sem); 566 pgd = pgd_offset(mm, addr); 567 if (!pgd_present(*pgd)) 568 goto bad_access; 569 pmd = pmd_offset(pgd, addr); 570 if (!pmd_present(*pmd)) 571 goto bad_access; 572 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 573 if (!pte_present(*pte) || !pte_dirty(*pte)) { 574 pte_unmap_unlock(pte, ptl); 575 goto bad_access; 576 } 577 val = *(unsigned long *)addr; 578 val -= regs->ARM_r0; 579 if (val == 0) { 580 *(unsigned long *)addr = regs->ARM_r1; 581 regs->ARM_cpsr |= PSR_C_BIT; 582 } 583 pte_unmap_unlock(pte, ptl); 584 up_read(&mm->mmap_sem); 585 return val; 586 587 bad_access: 588 up_read(&mm->mmap_sem); 589 /* simulate a write access fault */ 590 do_DataAbort(addr, 15 + (1 << 11), regs); 591 } 592#endif 593 594 default: 595 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 596 if not implemented, rather than raising SIGILL. This 597 way the calling program can gracefully determine whether 598 a feature is supported. */ 599 if ((no & 0xffff) <= 0x7ff) 600 return -ENOSYS; 601 break; 602 } 603#ifdef CONFIG_DEBUG_USER 604 /* 605 * experience shows that these seem to indicate that 606 * something catastrophic has happened 607 */ 608 if (user_debug & UDBG_SYSCALL) { 609 printk("[%d] %s: arm syscall %d\n", 610 task_pid_nr(current), current->comm, no); 611 dump_instr("", regs); 612 if (user_mode(regs)) { 613 __show_regs(regs); 614 c_backtrace(regs->ARM_fp, processor_mode(regs)); 615 } 616 } 617#endif 618 info.si_signo = SIGILL; 619 info.si_errno = 0; 620 info.si_code = ILL_ILLTRP; 621 info.si_addr = (void __user *)instruction_pointer(regs) - 622 (thumb_mode(regs) ? 2 : 4); 623 624 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); 625 return 0; 626} 627 628#ifdef CONFIG_TLS_REG_EMUL 629 630/* 631 * We might be running on an ARMv6+ processor which should have the TLS 632 * register but for some reason we can't use it, or maybe an SMP system 633 * using a pre-ARMv6 processor (there are apparently a few prototypes like 634 * that in existence) and therefore access to that register must be 635 * emulated. 636 */ 637 638static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 639{ 640 int reg = (instr >> 12) & 15; 641 if (reg == 15) 642 return 1; 643 regs->uregs[reg] = current_thread_info()->tp_value; 644 regs->ARM_pc += 4; 645 return 0; 646} 647 648static struct undef_hook arm_mrc_hook = { 649 .instr_mask = 0x0fff0fff, 650 .instr_val = 0x0e1d0f70, 651 .cpsr_mask = PSR_T_BIT, 652 .cpsr_val = 0, 653 .fn = get_tp_trap, 654}; 655 656static int __init arm_mrc_hook_init(void) 657{ 658 register_undef_hook(&arm_mrc_hook); 659 return 0; 660} 661 662late_initcall(arm_mrc_hook_init); 663 664#endif 665 666void __bad_xchg(volatile void *ptr, int size) 667{ 668 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", 669 __builtin_return_address(0), ptr, size); 670 BUG(); 671} 672EXPORT_SYMBOL(__bad_xchg); 673 674/* 675 * A data abort trap was taken, but we did not handle the instruction. 676 * Try to abort the user program, or panic if it was the kernel. 677 */ 678asmlinkage void 679baddataabort(int code, unsigned long instr, struct pt_regs *regs) 680{ 681 unsigned long addr = instruction_pointer(regs); 682 siginfo_t info; 683 684#ifdef CONFIG_DEBUG_USER 685 if (user_debug & UDBG_BADABORT) { 686 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", 687 task_pid_nr(current), current->comm, code, instr); 688 dump_instr(KERN_ERR, regs); 689 show_pte(current->mm, addr); 690 } 691#endif 692 693 info.si_signo = SIGILL; 694 info.si_errno = 0; 695 info.si_code = ILL_ILLOPC; 696 info.si_addr = (void __user *)addr; 697 698 arm_notify_die("unknown data abort code", regs, &info, instr, 0); 699} 700 701void __attribute__((noreturn)) __bug(const char *file, int line) 702{ 703 printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line); 704 *(int *)0 = 0; 705 706 /* Avoid "noreturn function does return" */ 707 for (;;); 708} 709EXPORT_SYMBOL(__bug); 710 711void __readwrite_bug(const char *fn) 712{ 713 printk("%s called, but not implemented\n", fn); 714 BUG(); 715} 716EXPORT_SYMBOL(__readwrite_bug); 717 718void __pte_error(const char *file, int line, unsigned long val) 719{ 720 printk("%s:%d: bad pte %08lx.\n", file, line, val); 721} 722 723void __pmd_error(const char *file, int line, unsigned long val) 724{ 725 printk("%s:%d: bad pmd %08lx.\n", file, line, val); 726} 727 728void __pgd_error(const char *file, int line, unsigned long val) 729{ 730 printk("%s:%d: bad pgd %08lx.\n", file, line, val); 731} 732 733asmlinkage void __div0(void) 734{ 735 printk("Division by zero in kernel.\n"); 736 dump_stack(); 737} 738EXPORT_SYMBOL(__div0); 739 740void abort(void) 741{ 742 BUG(); 743 744 /* if that doesn't kill us, halt */ 745 panic("Oops failed to kill thread"); 746} 747EXPORT_SYMBOL(abort); 748 749void __init trap_init(void) 750{ 751 return; 752} 753 754static void __init kuser_get_tls_init(unsigned long vectors) 755{ 756 /* 757 * vectors + 0xfe0 = __kuser_get_tls 758 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 759 */ 760 if (tls_emu || has_tls_reg) 761 memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4); 762} 763 764void __init early_trap_init(void) 765{ 766 unsigned long vectors = CONFIG_VECTORS_BASE; 767 extern char __stubs_start[], __stubs_end[]; 768 extern char __vectors_start[], __vectors_end[]; 769 extern char __kuser_helper_start[], __kuser_helper_end[]; 770 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 771 772 /* 773 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 774 * into the vector page, mapped at 0xffff0000, and ensure these 775 * are visible to the instruction stream. 776 */ 777 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 778 memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start); 779 memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 780 781 /* 782 * Do processor specific fixups for the kuser helpers 783 */ 784 kuser_get_tls_init(vectors); 785 786 /* 787 * Copy signal return handlers into the vector page, and 788 * set sigreturn to be a pointer to these. 789 */ 790 memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes, 791 sizeof(sigreturn_codes)); 792 memcpy((void *)KERN_RESTART_CODE, syscall_restart_code, 793 sizeof(syscall_restart_code)); 794 795 flush_icache_range(vectors, vectors + PAGE_SIZE); 796 modify_domain(DOMAIN_USER, DOMAIN_CLIENT); 797} 798