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/bug.h> 25 #include <linux/delay.h> 26 #include <linux/init.h> 27 #include <linux/sched.h> 28 29 #include <linux/atomic.h> 30 #include <asm/cacheflush.h> 31 #include <asm/exception.h> 32 #include <asm/unistd.h> 33 #include <asm/traps.h> 34 #include <asm/unwind.h> 35 #include <asm/tls.h> 36 #include <asm/system_misc.h> 37 38 #include "signal.h" 39 40 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; 41 42 void *vectors_page; 43 44 #ifdef CONFIG_DEBUG_USER 45 unsigned int user_debug; 46 47 static int __init user_debug_setup(char *str) 48 { 49 get_option(&str, &user_debug); 50 return 1; 51 } 52 __setup("user_debug=", user_debug_setup); 53 #endif 54 55 static void dump_mem(const char *, const char *, unsigned long, unsigned long); 56 57 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) 58 { 59 #ifdef CONFIG_KALLSYMS 60 printk("[<%08lx>] (%pS) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); 61 #else 62 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); 63 #endif 64 65 if (in_exception_text(where)) 66 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); 67 } 68 69 #ifndef CONFIG_ARM_UNWIND 70 /* 71 * Stack pointers should always be within the kernels view of 72 * physical memory. If it is not there, then we can't dump 73 * out any information relating to the stack. 74 */ 75 static int verify_stack(unsigned long sp) 76 { 77 if (sp < PAGE_OFFSET || 78 (sp > (unsigned long)high_memory && high_memory != NULL)) 79 return -EFAULT; 80 81 return 0; 82 } 83 #endif 84 85 /* 86 * Dump out the contents of some memory nicely... 87 */ 88 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 89 unsigned long top) 90 { 91 unsigned long first; 92 mm_segment_t fs; 93 int i; 94 95 /* 96 * We need to switch to kernel mode so that we can use __get_user 97 * to safely read from kernel space. Note that we now dump the 98 * code first, just in case the backtrace kills us. 99 */ 100 fs = get_fs(); 101 set_fs(KERNEL_DS); 102 103 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 104 105 for (first = bottom & ~31; first < top; first += 32) { 106 unsigned long p; 107 char str[sizeof(" 12345678") * 8 + 1]; 108 109 memset(str, ' ', sizeof(str)); 110 str[sizeof(str) - 1] = '\0'; 111 112 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 113 if (p >= bottom && p < top) { 114 unsigned long val; 115 if (__get_user(val, (unsigned long *)p) == 0) 116 sprintf(str + i * 9, " %08lx", val); 117 else 118 sprintf(str + i * 9, " ????????"); 119 } 120 } 121 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 122 } 123 124 set_fs(fs); 125 } 126 127 static void dump_instr(const char *lvl, struct pt_regs *regs) 128 { 129 unsigned long addr = instruction_pointer(regs); 130 const int thumb = thumb_mode(regs); 131 const int width = thumb ? 4 : 8; 132 mm_segment_t fs; 133 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 134 int i; 135 136 /* 137 * We need to switch to kernel mode so that we can use __get_user 138 * to safely read from kernel space. Note that we now dump the 139 * code first, just in case the backtrace kills us. 140 */ 141 fs = get_fs(); 142 set_fs(KERNEL_DS); 143 144 for (i = -4; i < 1 + !!thumb; i++) { 145 unsigned int val, bad; 146 147 if (thumb) 148 bad = __get_user(val, &((u16 *)addr)[i]); 149 else 150 bad = __get_user(val, &((u32 *)addr)[i]); 151 152 if (!bad) 153 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 154 width, val); 155 else { 156 p += sprintf(p, "bad PC value"); 157 break; 158 } 159 } 160 printk("%sCode: %s\n", lvl, str); 161 162 set_fs(fs); 163 } 164 165 #ifdef CONFIG_ARM_UNWIND 166 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 167 { 168 unwind_backtrace(regs, tsk); 169 } 170 #else 171 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 172 { 173 unsigned int fp, mode; 174 int ok = 1; 175 176 printk("Backtrace: "); 177 178 if (!tsk) 179 tsk = current; 180 181 if (regs) { 182 fp = regs->ARM_fp; 183 mode = processor_mode(regs); 184 } else if (tsk != current) { 185 fp = thread_saved_fp(tsk); 186 mode = 0x10; 187 } else { 188 asm("mov %0, fp" : "=r" (fp) : : "cc"); 189 mode = 0x10; 190 } 191 192 if (!fp) { 193 printk("no frame pointer"); 194 ok = 0; 195 } else if (verify_stack(fp)) { 196 printk("invalid frame pointer 0x%08x", fp); 197 ok = 0; 198 } else if (fp < (unsigned long)end_of_stack(tsk)) 199 printk("frame pointer underflow"); 200 printk("\n"); 201 202 if (ok) 203 c_backtrace(fp, mode); 204 } 205 #endif 206 207 void show_stack(struct task_struct *tsk, unsigned long *sp) 208 { 209 dump_backtrace(NULL, tsk); 210 barrier(); 211 } 212 213 #ifdef CONFIG_PREEMPT 214 #define S_PREEMPT " PREEMPT" 215 #else 216 #define S_PREEMPT "" 217 #endif 218 #ifdef CONFIG_SMP 219 #define S_SMP " SMP" 220 #else 221 #define S_SMP "" 222 #endif 223 #ifdef CONFIG_THUMB2_KERNEL 224 #define S_ISA " THUMB2" 225 #else 226 #define S_ISA " ARM" 227 #endif 228 229 static int __die(const char *str, int err, struct pt_regs *regs) 230 { 231 struct task_struct *tsk = current; 232 static int die_counter; 233 int ret; 234 235 printk(KERN_EMERG "Internal error: %s: %x [#%d]" S_PREEMPT S_SMP 236 S_ISA "\n", 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 1; 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), end_of_stack(tsk)); 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 0; 256 } 257 258 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; 259 static int die_owner = -1; 260 static unsigned int die_nest_count; 261 262 static unsigned long oops_begin(void) 263 { 264 int cpu; 265 unsigned long flags; 266 267 oops_enter(); 268 269 /* racy, but better than risking deadlock. */ 270 raw_local_irq_save(flags); 271 cpu = smp_processor_id(); 272 if (!arch_spin_trylock(&die_lock)) { 273 if (cpu == die_owner) 274 /* nested oops. should stop eventually */; 275 else 276 arch_spin_lock(&die_lock); 277 } 278 die_nest_count++; 279 die_owner = cpu; 280 console_verbose(); 281 bust_spinlocks(1); 282 return flags; 283 } 284 285 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) 286 { 287 if (regs && kexec_should_crash(current)) 288 crash_kexec(regs); 289 290 bust_spinlocks(0); 291 die_owner = -1; 292 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 293 die_nest_count--; 294 if (!die_nest_count) 295 /* Nest count reaches zero, release the lock. */ 296 arch_spin_unlock(&die_lock); 297 raw_local_irq_restore(flags); 298 oops_exit(); 299 300 if (in_interrupt()) 301 panic("Fatal exception in interrupt"); 302 if (panic_on_oops) 303 panic("Fatal exception"); 304 if (signr) 305 do_exit(signr); 306 } 307 308 /* 309 * This function is protected against re-entrancy. 310 */ 311 void die(const char *str, struct pt_regs *regs, int err) 312 { 313 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; 314 unsigned long flags = oops_begin(); 315 int sig = SIGSEGV; 316 317 if (!user_mode(regs)) 318 bug_type = report_bug(regs->ARM_pc, regs); 319 if (bug_type != BUG_TRAP_TYPE_NONE) 320 str = "Oops - BUG"; 321 322 if (__die(str, err, regs)) 323 sig = 0; 324 325 oops_end(flags, regs, sig); 326 } 327 328 void arm_notify_die(const char *str, struct pt_regs *regs, 329 struct siginfo *info, unsigned long err, unsigned long trap) 330 { 331 if (user_mode(regs)) { 332 current->thread.error_code = err; 333 current->thread.trap_no = trap; 334 335 force_sig_info(info->si_signo, info, current); 336 } else { 337 die(str, regs, err); 338 } 339 } 340 341 #ifdef CONFIG_GENERIC_BUG 342 343 int is_valid_bugaddr(unsigned long pc) 344 { 345 #ifdef CONFIG_THUMB2_KERNEL 346 unsigned short bkpt; 347 #else 348 unsigned long bkpt; 349 #endif 350 351 if (probe_kernel_address((unsigned *)pc, bkpt)) 352 return 0; 353 354 return bkpt == BUG_INSTR_VALUE; 355 } 356 357 #endif 358 359 static LIST_HEAD(undef_hook); 360 static DEFINE_RAW_SPINLOCK(undef_lock); 361 362 void register_undef_hook(struct undef_hook *hook) 363 { 364 unsigned long flags; 365 366 raw_spin_lock_irqsave(&undef_lock, flags); 367 list_add(&hook->node, &undef_hook); 368 raw_spin_unlock_irqrestore(&undef_lock, flags); 369 } 370 371 void unregister_undef_hook(struct undef_hook *hook) 372 { 373 unsigned long flags; 374 375 raw_spin_lock_irqsave(&undef_lock, flags); 376 list_del(&hook->node); 377 raw_spin_unlock_irqrestore(&undef_lock, flags); 378 } 379 380 static int call_undef_hook(struct pt_regs *regs, unsigned int instr) 381 { 382 struct undef_hook *hook; 383 unsigned long flags; 384 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 385 386 raw_spin_lock_irqsave(&undef_lock, flags); 387 list_for_each_entry(hook, &undef_hook, node) 388 if ((instr & hook->instr_mask) == hook->instr_val && 389 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 390 fn = hook->fn; 391 raw_spin_unlock_irqrestore(&undef_lock, flags); 392 393 return fn ? fn(regs, instr) : 1; 394 } 395 396 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 397 { 398 unsigned int instr; 399 siginfo_t info; 400 void __user *pc; 401 402 pc = (void __user *)instruction_pointer(regs); 403 404 if (processor_mode(regs) == SVC_MODE) { 405 #ifdef CONFIG_THUMB2_KERNEL 406 if (thumb_mode(regs)) { 407 instr = ((u16 *)pc)[0]; 408 if (is_wide_instruction(instr)) { 409 instr <<= 16; 410 instr |= ((u16 *)pc)[1]; 411 } 412 } else 413 #endif 414 instr = *(u32 *) pc; 415 } else if (thumb_mode(regs)) { 416 if (get_user(instr, (u16 __user *)pc)) 417 goto die_sig; 418 if (is_wide_instruction(instr)) { 419 unsigned int instr2; 420 if (get_user(instr2, (u16 __user *)pc+1)) 421 goto die_sig; 422 instr <<= 16; 423 instr |= instr2; 424 } 425 } else if (get_user(instr, (u32 __user *)pc)) { 426 goto die_sig; 427 } 428 429 if (call_undef_hook(regs, instr) == 0) 430 return; 431 432 die_sig: 433 #ifdef CONFIG_DEBUG_USER 434 if (user_debug & UDBG_UNDEFINED) { 435 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", 436 current->comm, task_pid_nr(current), pc); 437 dump_instr(KERN_INFO, regs); 438 } 439 #endif 440 441 info.si_signo = SIGILL; 442 info.si_errno = 0; 443 info.si_code = ILL_ILLOPC; 444 info.si_addr = pc; 445 446 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); 447 } 448 449 asmlinkage void do_unexp_fiq (struct pt_regs *regs) 450 { 451 printk("Hmm. Unexpected FIQ received, but trying to continue\n"); 452 printk("You may have a hardware problem...\n"); 453 } 454 455 /* 456 * bad_mode handles the impossible case in the vectors. If you see one of 457 * these, then it's extremely serious, and could mean you have buggy hardware. 458 * It never returns, and never tries to sync. We hope that we can at least 459 * dump out some state information... 460 */ 461 asmlinkage void bad_mode(struct pt_regs *regs, int reason) 462 { 463 console_verbose(); 464 465 printk(KERN_CRIT "Bad mode in %s handler detected\n", handler[reason]); 466 467 die("Oops - bad mode", regs, 0); 468 local_irq_disable(); 469 panic("bad mode"); 470 } 471 472 static int bad_syscall(int n, struct pt_regs *regs) 473 { 474 struct thread_info *thread = current_thread_info(); 475 siginfo_t info; 476 477 if ((current->personality & PER_MASK) != PER_LINUX && 478 thread->exec_domain->handler) { 479 thread->exec_domain->handler(n, regs); 480 return regs->ARM_r0; 481 } 482 483 #ifdef CONFIG_DEBUG_USER 484 if (user_debug & UDBG_SYSCALL) { 485 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n", 486 task_pid_nr(current), current->comm, n); 487 dump_instr(KERN_ERR, regs); 488 } 489 #endif 490 491 info.si_signo = SIGILL; 492 info.si_errno = 0; 493 info.si_code = ILL_ILLTRP; 494 info.si_addr = (void __user *)instruction_pointer(regs) - 495 (thumb_mode(regs) ? 2 : 4); 496 497 arm_notify_die("Oops - bad syscall", regs, &info, n, 0); 498 499 return regs->ARM_r0; 500 } 501 502 static inline int 503 do_cache_op(unsigned long start, unsigned long end, int flags) 504 { 505 struct mm_struct *mm = current->active_mm; 506 struct vm_area_struct *vma; 507 508 if (end < start || flags) 509 return -EINVAL; 510 511 down_read(&mm->mmap_sem); 512 vma = find_vma(mm, start); 513 if (vma && vma->vm_start < end) { 514 if (start < vma->vm_start) 515 start = vma->vm_start; 516 if (end > vma->vm_end) 517 end = vma->vm_end; 518 519 up_read(&mm->mmap_sem); 520 return flush_cache_user_range(start, end); 521 } 522 up_read(&mm->mmap_sem); 523 return -EINVAL; 524 } 525 526 /* 527 * Handle all unrecognised system calls. 528 * 0x9f0000 - 0x9fffff are some more esoteric system calls 529 */ 530 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 531 asmlinkage int arm_syscall(int no, struct pt_regs *regs) 532 { 533 struct thread_info *thread = current_thread_info(); 534 siginfo_t info; 535 536 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 537 return bad_syscall(no, regs); 538 539 switch (no & 0xffff) { 540 case 0: /* branch through 0 */ 541 info.si_signo = SIGSEGV; 542 info.si_errno = 0; 543 info.si_code = SEGV_MAPERR; 544 info.si_addr = NULL; 545 546 arm_notify_die("branch through zero", regs, &info, 0, 0); 547 return 0; 548 549 case NR(breakpoint): /* SWI BREAK_POINT */ 550 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 551 ptrace_break(current, regs); 552 return regs->ARM_r0; 553 554 /* 555 * Flush a region from virtual address 'r0' to virtual address 'r1' 556 * _exclusive_. There is no alignment requirement on either address; 557 * user space does not need to know the hardware cache layout. 558 * 559 * r2 contains flags. It should ALWAYS be passed as ZERO until it 560 * is defined to be something else. For now we ignore it, but may 561 * the fires of hell burn in your belly if you break this rule. ;) 562 * 563 * (at a later date, we may want to allow this call to not flush 564 * various aspects of the cache. Passing '0' will guarantee that 565 * everything necessary gets flushed to maintain consistency in 566 * the specified region). 567 */ 568 case NR(cacheflush): 569 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 570 571 case NR(usr26): 572 if (!(elf_hwcap & HWCAP_26BIT)) 573 break; 574 regs->ARM_cpsr &= ~MODE32_BIT; 575 return regs->ARM_r0; 576 577 case NR(usr32): 578 if (!(elf_hwcap & HWCAP_26BIT)) 579 break; 580 regs->ARM_cpsr |= MODE32_BIT; 581 return regs->ARM_r0; 582 583 case NR(set_tls): 584 thread->tp_value[0] = regs->ARM_r0; 585 if (tls_emu) 586 return 0; 587 if (has_tls_reg) { 588 asm ("mcr p15, 0, %0, c13, c0, 3" 589 : : "r" (regs->ARM_r0)); 590 } else { 591 /* 592 * User space must never try to access this directly. 593 * Expect your app to break eventually if you do so. 594 * The user helper at 0xffff0fe0 must be used instead. 595 * (see entry-armv.S for details) 596 */ 597 *((unsigned int *)0xffff0ff0) = regs->ARM_r0; 598 } 599 return 0; 600 601 #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG 602 /* 603 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. 604 * Return zero in r0 if *MEM was changed or non-zero if no exchange 605 * happened. Also set the user C flag accordingly. 606 * If access permissions have to be fixed up then non-zero is 607 * returned and the operation has to be re-attempted. 608 * 609 * *NOTE*: This is a ghost syscall private to the kernel. Only the 610 * __kuser_cmpxchg code in entry-armv.S should be aware of its 611 * existence. Don't ever use this from user code. 612 */ 613 case NR(cmpxchg): 614 for (;;) { 615 extern void do_DataAbort(unsigned long addr, unsigned int fsr, 616 struct pt_regs *regs); 617 unsigned long val; 618 unsigned long addr = regs->ARM_r2; 619 struct mm_struct *mm = current->mm; 620 pgd_t *pgd; pmd_t *pmd; pte_t *pte; 621 spinlock_t *ptl; 622 623 regs->ARM_cpsr &= ~PSR_C_BIT; 624 down_read(&mm->mmap_sem); 625 pgd = pgd_offset(mm, addr); 626 if (!pgd_present(*pgd)) 627 goto bad_access; 628 pmd = pmd_offset(pgd, addr); 629 if (!pmd_present(*pmd)) 630 goto bad_access; 631 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 632 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) { 633 pte_unmap_unlock(pte, ptl); 634 goto bad_access; 635 } 636 val = *(unsigned long *)addr; 637 val -= regs->ARM_r0; 638 if (val == 0) { 639 *(unsigned long *)addr = regs->ARM_r1; 640 regs->ARM_cpsr |= PSR_C_BIT; 641 } 642 pte_unmap_unlock(pte, ptl); 643 up_read(&mm->mmap_sem); 644 return val; 645 646 bad_access: 647 up_read(&mm->mmap_sem); 648 /* simulate a write access fault */ 649 do_DataAbort(addr, 15 + (1 << 11), regs); 650 } 651 #endif 652 653 default: 654 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 655 if not implemented, rather than raising SIGILL. This 656 way the calling program can gracefully determine whether 657 a feature is supported. */ 658 if ((no & 0xffff) <= 0x7ff) 659 return -ENOSYS; 660 break; 661 } 662 #ifdef CONFIG_DEBUG_USER 663 /* 664 * experience shows that these seem to indicate that 665 * something catastrophic has happened 666 */ 667 if (user_debug & UDBG_SYSCALL) { 668 printk("[%d] %s: arm syscall %d\n", 669 task_pid_nr(current), current->comm, no); 670 dump_instr("", regs); 671 if (user_mode(regs)) { 672 __show_regs(regs); 673 c_backtrace(regs->ARM_fp, processor_mode(regs)); 674 } 675 } 676 #endif 677 info.si_signo = SIGILL; 678 info.si_errno = 0; 679 info.si_code = ILL_ILLTRP; 680 info.si_addr = (void __user *)instruction_pointer(regs) - 681 (thumb_mode(regs) ? 2 : 4); 682 683 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); 684 return 0; 685 } 686 687 #ifdef CONFIG_TLS_REG_EMUL 688 689 /* 690 * We might be running on an ARMv6+ processor which should have the TLS 691 * register but for some reason we can't use it, or maybe an SMP system 692 * using a pre-ARMv6 processor (there are apparently a few prototypes like 693 * that in existence) and therefore access to that register must be 694 * emulated. 695 */ 696 697 static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 698 { 699 int reg = (instr >> 12) & 15; 700 if (reg == 15) 701 return 1; 702 regs->uregs[reg] = current_thread_info()->tp_value[0]; 703 regs->ARM_pc += 4; 704 return 0; 705 } 706 707 static struct undef_hook arm_mrc_hook = { 708 .instr_mask = 0x0fff0fff, 709 .instr_val = 0x0e1d0f70, 710 .cpsr_mask = PSR_T_BIT, 711 .cpsr_val = 0, 712 .fn = get_tp_trap, 713 }; 714 715 static int __init arm_mrc_hook_init(void) 716 { 717 register_undef_hook(&arm_mrc_hook); 718 return 0; 719 } 720 721 late_initcall(arm_mrc_hook_init); 722 723 #endif 724 725 void __bad_xchg(volatile void *ptr, int size) 726 { 727 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", 728 __builtin_return_address(0), ptr, size); 729 BUG(); 730 } 731 EXPORT_SYMBOL(__bad_xchg); 732 733 /* 734 * A data abort trap was taken, but we did not handle the instruction. 735 * Try to abort the user program, or panic if it was the kernel. 736 */ 737 asmlinkage void 738 baddataabort(int code, unsigned long instr, struct pt_regs *regs) 739 { 740 unsigned long addr = instruction_pointer(regs); 741 siginfo_t info; 742 743 #ifdef CONFIG_DEBUG_USER 744 if (user_debug & UDBG_BADABORT) { 745 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", 746 task_pid_nr(current), current->comm, code, instr); 747 dump_instr(KERN_ERR, regs); 748 show_pte(current->mm, addr); 749 } 750 #endif 751 752 info.si_signo = SIGILL; 753 info.si_errno = 0; 754 info.si_code = ILL_ILLOPC; 755 info.si_addr = (void __user *)addr; 756 757 arm_notify_die("unknown data abort code", regs, &info, instr, 0); 758 } 759 760 void __readwrite_bug(const char *fn) 761 { 762 printk("%s called, but not implemented\n", fn); 763 BUG(); 764 } 765 EXPORT_SYMBOL(__readwrite_bug); 766 767 void __pte_error(const char *file, int line, pte_t pte) 768 { 769 printk("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 770 } 771 772 void __pmd_error(const char *file, int line, pmd_t pmd) 773 { 774 printk("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 775 } 776 777 void __pgd_error(const char *file, int line, pgd_t pgd) 778 { 779 printk("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 780 } 781 782 asmlinkage void __div0(void) 783 { 784 printk("Division by zero in kernel.\n"); 785 dump_stack(); 786 } 787 EXPORT_SYMBOL(__div0); 788 789 void abort(void) 790 { 791 BUG(); 792 793 /* if that doesn't kill us, halt */ 794 panic("Oops failed to kill thread"); 795 } 796 EXPORT_SYMBOL(abort); 797 798 void __init trap_init(void) 799 { 800 return; 801 } 802 803 static void __init kuser_get_tls_init(unsigned long vectors) 804 { 805 /* 806 * vectors + 0xfe0 = __kuser_get_tls 807 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 808 */ 809 if (tls_emu || has_tls_reg) 810 memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4); 811 } 812 813 void __init early_trap_init(void *vectors_base) 814 { 815 #ifndef CONFIG_CPU_V7M 816 unsigned long vectors = (unsigned long)vectors_base; 817 extern char __stubs_start[], __stubs_end[]; 818 extern char __vectors_start[], __vectors_end[]; 819 extern char __kuser_helper_start[], __kuser_helper_end[]; 820 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 821 822 vectors_page = vectors_base; 823 824 /* 825 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 826 * into the vector page, mapped at 0xffff0000, and ensure these 827 * are visible to the instruction stream. 828 */ 829 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 830 memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start); 831 memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 832 833 /* 834 * Do processor specific fixups for the kuser helpers 835 */ 836 kuser_get_tls_init(vectors); 837 838 /* 839 * Copy signal return handlers into the vector page, and 840 * set sigreturn to be a pointer to these. 841 */ 842 memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE), 843 sigreturn_codes, sizeof(sigreturn_codes)); 844 845 flush_icache_range(vectors, vectors + PAGE_SIZE); 846 modify_domain(DOMAIN_USER, DOMAIN_CLIENT); 847 #else /* ifndef CONFIG_CPU_V7M */ 848 /* 849 * on V7-M there is no need to copy the vector table to a dedicated 850 * memory area. The address is configurable and so a table in the kernel 851 * image can be used. 852 */ 853 #endif 854 } 855