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#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 42static const char *handler[]= { 43 "prefetch abort", 44 "data abort", 45 "address exception", 46 "interrupt", 47 "undefined instruction", 48}; 49 50void *vectors_page; 51 52#ifdef CONFIG_DEBUG_USER 53unsigned int user_debug; 54 55static 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 63static void dump_mem(const char *, const char *, unsigned long, unsigned long); 64 65void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) 66{ 67#ifdef CONFIG_KALLSYMS 68 printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); 69#else 70 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); 71#endif 72 73 if (in_exception_text(where)) 74 dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); 75} 76 77#ifndef CONFIG_ARM_UNWIND 78/* 79 * Stack pointers should always be within the kernels view of 80 * physical memory. If it is not there, then we can't dump 81 * out any information relating to the stack. 82 */ 83static int verify_stack(unsigned long sp) 84{ 85 if (sp < PAGE_OFFSET || 86 (sp > (unsigned long)high_memory && high_memory != NULL)) 87 return -EFAULT; 88 89 return 0; 90} 91#endif 92 93/* 94 * Dump out the contents of some memory nicely... 95 */ 96static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 97 unsigned long top) 98{ 99 unsigned long first; 100 mm_segment_t fs; 101 int i; 102 103 /* 104 * We need to switch to kernel mode so that we can use __get_user 105 * to safely read from kernel space. Note that we now dump the 106 * code first, just in case the backtrace kills us. 107 */ 108 fs = get_fs(); 109 set_fs(KERNEL_DS); 110 111 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); 112 113 for (first = bottom & ~31; first < top; first += 32) { 114 unsigned long p; 115 char str[sizeof(" 12345678") * 8 + 1]; 116 117 memset(str, ' ', sizeof(str)); 118 str[sizeof(str) - 1] = '\0'; 119 120 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 121 if (p >= bottom && p < top) { 122 unsigned long val; 123 if (__get_user(val, (unsigned long *)p) == 0) 124 sprintf(str + i * 9, " %08lx", val); 125 else 126 sprintf(str + i * 9, " ????????"); 127 } 128 } 129 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 130 } 131 132 set_fs(fs); 133} 134 135static void dump_instr(const char *lvl, struct pt_regs *regs) 136{ 137 unsigned long addr = instruction_pointer(regs); 138 const int thumb = thumb_mode(regs); 139 const int width = thumb ? 4 : 8; 140 mm_segment_t fs; 141 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 142 int i; 143 144 /* 145 * We need to switch to kernel mode so that we can use __get_user 146 * to safely read from kernel space. Note that we now dump the 147 * code first, just in case the backtrace kills us. 148 */ 149 fs = get_fs(); 150 set_fs(KERNEL_DS); 151 152 for (i = -4; i < 1 + !!thumb; i++) { 153 unsigned int val, bad; 154 155 if (thumb) 156 bad = __get_user(val, &((u16 *)addr)[i]); 157 else 158 bad = __get_user(val, &((u32 *)addr)[i]); 159 160 if (!bad) 161 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", 162 width, val); 163 else { 164 p += sprintf(p, "bad PC value"); 165 break; 166 } 167 } 168 printk("%sCode: %s\n", lvl, str); 169 170 set_fs(fs); 171} 172 173#ifdef CONFIG_ARM_UNWIND 174static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 175{ 176 unwind_backtrace(regs, tsk); 177} 178#else 179static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 180{ 181 unsigned int fp, mode; 182 int ok = 1; 183 184 printk("Backtrace: "); 185 186 if (!tsk) 187 tsk = current; 188 189 if (regs) { 190 fp = frame_pointer(regs); 191 mode = processor_mode(regs); 192 } else if (tsk != current) { 193 fp = thread_saved_fp(tsk); 194 mode = 0x10; 195 } else { 196 asm("mov %0, fp" : "=r" (fp) : : "cc"); 197 mode = 0x10; 198 } 199 200 if (!fp) { 201 pr_cont("no frame pointer"); 202 ok = 0; 203 } else if (verify_stack(fp)) { 204 pr_cont("invalid frame pointer 0x%08x", fp); 205 ok = 0; 206 } else if (fp < (unsigned long)end_of_stack(tsk)) 207 pr_cont("frame pointer underflow"); 208 pr_cont("\n"); 209 210 if (ok) 211 c_backtrace(fp, mode); 212} 213#endif 214 215void show_stack(struct task_struct *tsk, unsigned long *sp) 216{ 217 dump_backtrace(NULL, tsk); 218 barrier(); 219} 220 221#ifdef CONFIG_PREEMPT 222#define S_PREEMPT " PREEMPT" 223#else 224#define S_PREEMPT "" 225#endif 226#ifdef CONFIG_SMP 227#define S_SMP " SMP" 228#else 229#define S_SMP "" 230#endif 231#ifdef CONFIG_THUMB2_KERNEL 232#define S_ISA " THUMB2" 233#else 234#define S_ISA " ARM" 235#endif 236 237static int __die(const char *str, int err, struct pt_regs *regs) 238{ 239 struct task_struct *tsk = current; 240 static int die_counter; 241 int ret; 242 243 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", 244 str, err, ++die_counter); 245 246 /* trap and error numbers are mostly meaningless on ARM */ 247 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); 248 if (ret == NOTIFY_STOP) 249 return 1; 250 251 print_modules(); 252 __show_regs(regs); 253 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 254 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); 255 256 if (!user_mode(regs) || in_interrupt()) { 257 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, 258 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 259 dump_backtrace(regs, tsk); 260 dump_instr(KERN_EMERG, regs); 261 } 262 263 return 0; 264} 265 266static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; 267static int die_owner = -1; 268static unsigned int die_nest_count; 269 270static unsigned long oops_begin(void) 271{ 272 int cpu; 273 unsigned long flags; 274 275 oops_enter(); 276 277 /* racy, but better than risking deadlock. */ 278 raw_local_irq_save(flags); 279 cpu = smp_processor_id(); 280 if (!arch_spin_trylock(&die_lock)) { 281 if (cpu == die_owner) 282 /* nested oops. should stop eventually */; 283 else 284 arch_spin_lock(&die_lock); 285 } 286 die_nest_count++; 287 die_owner = cpu; 288 console_verbose(); 289 bust_spinlocks(1); 290 return flags; 291} 292 293static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) 294{ 295 if (regs && kexec_should_crash(current)) 296 crash_kexec(regs); 297 298 bust_spinlocks(0); 299 die_owner = -1; 300 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 301 die_nest_count--; 302 if (!die_nest_count) 303 /* Nest count reaches zero, release the lock. */ 304 arch_spin_unlock(&die_lock); 305 raw_local_irq_restore(flags); 306 oops_exit(); 307 308 if (in_interrupt()) 309 panic("Fatal exception in interrupt"); 310 if (panic_on_oops) 311 panic("Fatal exception"); 312 if (signr) 313 do_exit(signr); 314} 315 316/* 317 * This function is protected against re-entrancy. 318 */ 319void die(const char *str, struct pt_regs *regs, int err) 320{ 321 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; 322 unsigned long flags = oops_begin(); 323 int sig = SIGSEGV; 324 325 if (!user_mode(regs)) 326 bug_type = report_bug(regs->ARM_pc, regs); 327 if (bug_type != BUG_TRAP_TYPE_NONE) 328 str = "Oops - BUG"; 329 330 if (__die(str, err, regs)) 331 sig = 0; 332 333 oops_end(flags, regs, sig); 334} 335 336void arm_notify_die(const char *str, struct pt_regs *regs, 337 struct siginfo *info, unsigned long err, unsigned long trap) 338{ 339 if (user_mode(regs)) { 340 current->thread.error_code = err; 341 current->thread.trap_no = trap; 342 343 force_sig_info(info->si_signo, info, current); 344 } else { 345 die(str, regs, err); 346 } 347} 348 349#ifdef CONFIG_GENERIC_BUG 350 351int is_valid_bugaddr(unsigned long pc) 352{ 353#ifdef CONFIG_THUMB2_KERNEL 354 u16 bkpt; 355 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); 356#else 357 u32 bkpt; 358 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); 359#endif 360 361 if (probe_kernel_address((unsigned *)pc, bkpt)) 362 return 0; 363 364 return bkpt == insn; 365} 366 367#endif 368 369static LIST_HEAD(undef_hook); 370static DEFINE_RAW_SPINLOCK(undef_lock); 371 372void register_undef_hook(struct undef_hook *hook) 373{ 374 unsigned long flags; 375 376 raw_spin_lock_irqsave(&undef_lock, flags); 377 list_add(&hook->node, &undef_hook); 378 raw_spin_unlock_irqrestore(&undef_lock, flags); 379} 380 381void unregister_undef_hook(struct undef_hook *hook) 382{ 383 unsigned long flags; 384 385 raw_spin_lock_irqsave(&undef_lock, flags); 386 list_del(&hook->node); 387 raw_spin_unlock_irqrestore(&undef_lock, flags); 388} 389 390static int call_undef_hook(struct pt_regs *regs, unsigned int instr) 391{ 392 struct undef_hook *hook; 393 unsigned long flags; 394 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; 395 396 raw_spin_lock_irqsave(&undef_lock, flags); 397 list_for_each_entry(hook, &undef_hook, node) 398 if ((instr & hook->instr_mask) == hook->instr_val && 399 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) 400 fn = hook->fn; 401 raw_spin_unlock_irqrestore(&undef_lock, flags); 402 403 return fn ? fn(regs, instr) : 1; 404} 405 406asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 407{ 408 unsigned int instr; 409 siginfo_t info; 410 void __user *pc; 411 412 pc = (void __user *)instruction_pointer(regs); 413 414 if (processor_mode(regs) == SVC_MODE) { 415#ifdef CONFIG_THUMB2_KERNEL 416 if (thumb_mode(regs)) { 417 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); 418 if (is_wide_instruction(instr)) { 419 u16 inst2; 420 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); 421 instr = __opcode_thumb32_compose(instr, inst2); 422 } 423 } else 424#endif 425 instr = __mem_to_opcode_arm(*(u32 *) pc); 426 } else if (thumb_mode(regs)) { 427 if (get_user(instr, (u16 __user *)pc)) 428 goto die_sig; 429 instr = __mem_to_opcode_thumb16(instr); 430 if (is_wide_instruction(instr)) { 431 unsigned int instr2; 432 if (get_user(instr2, (u16 __user *)pc+1)) 433 goto die_sig; 434 instr2 = __mem_to_opcode_thumb16(instr2); 435 instr = __opcode_thumb32_compose(instr, instr2); 436 } 437 } else { 438 if (get_user(instr, (u32 __user *)pc)) 439 goto die_sig; 440 instr = __mem_to_opcode_arm(instr); 441 } 442 443 if (call_undef_hook(regs, instr) == 0) 444 return; 445 446die_sig: 447#ifdef CONFIG_DEBUG_USER 448 if (user_debug & UDBG_UNDEFINED) { 449 pr_info("%s (%d): undefined instruction: pc=%p\n", 450 current->comm, task_pid_nr(current), pc); 451 __show_regs(regs); 452 dump_instr(KERN_INFO, regs); 453 } 454#endif 455 456 info.si_signo = SIGILL; 457 info.si_errno = 0; 458 info.si_code = ILL_ILLOPC; 459 info.si_addr = pc; 460 461 arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); 462} 463 464/* 465 * Handle FIQ similarly to NMI on x86 systems. 466 * 467 * The runtime environment for NMIs is extremely restrictive 468 * (NMIs can pre-empt critical sections meaning almost all locking is 469 * forbidden) meaning this default FIQ handling must only be used in 470 * circumstances where non-maskability improves robustness, such as 471 * watchdog or debug logic. 472 * 473 * This handler is not appropriate for general purpose use in drivers 474 * platform code and can be overrideen using set_fiq_handler. 475 */ 476asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) 477{ 478 struct pt_regs *old_regs = set_irq_regs(regs); 479 480 nmi_enter(); 481 482 /* nop. FIQ handlers for special arch/arm features can be added here. */ 483 484 nmi_exit(); 485 486 set_irq_regs(old_regs); 487} 488 489/* 490 * bad_mode handles the impossible case in the vectors. If you see one of 491 * these, then it's extremely serious, and could mean you have buggy hardware. 492 * It never returns, and never tries to sync. We hope that we can at least 493 * dump out some state information... 494 */ 495asmlinkage void bad_mode(struct pt_regs *regs, int reason) 496{ 497 console_verbose(); 498 499 pr_crit("Bad mode in %s handler detected\n", handler[reason]); 500 501 die("Oops - bad mode", regs, 0); 502 local_irq_disable(); 503 panic("bad mode"); 504} 505 506static int bad_syscall(int n, struct pt_regs *regs) 507{ 508 siginfo_t info; 509 510 if ((current->personality & PER_MASK) != PER_LINUX) { 511 send_sig(SIGSEGV, current, 1); 512 return regs->ARM_r0; 513 } 514 515#ifdef CONFIG_DEBUG_USER 516 if (user_debug & UDBG_SYSCALL) { 517 pr_err("[%d] %s: obsolete system call %08x.\n", 518 task_pid_nr(current), current->comm, n); 519 dump_instr(KERN_ERR, regs); 520 } 521#endif 522 523 info.si_signo = SIGILL; 524 info.si_errno = 0; 525 info.si_code = ILL_ILLTRP; 526 info.si_addr = (void __user *)instruction_pointer(regs) - 527 (thumb_mode(regs) ? 2 : 4); 528 529 arm_notify_die("Oops - bad syscall", regs, &info, n, 0); 530 531 return regs->ARM_r0; 532} 533 534static inline int 535__do_cache_op(unsigned long start, unsigned long end) 536{ 537 int ret; 538 539 do { 540 unsigned long chunk = min(PAGE_SIZE, end - start); 541 542 if (fatal_signal_pending(current)) 543 return 0; 544 545 ret = flush_cache_user_range(start, start + chunk); 546 if (ret) 547 return ret; 548 549 cond_resched(); 550 start += chunk; 551 } while (start < end); 552 553 return 0; 554} 555 556static inline int 557do_cache_op(unsigned long start, unsigned long end, int flags) 558{ 559 if (end < start || flags) 560 return -EINVAL; 561 562 if (!access_ok(VERIFY_READ, start, end - start)) 563 return -EFAULT; 564 565 return __do_cache_op(start, end); 566} 567 568/* 569 * Handle all unrecognised system calls. 570 * 0x9f0000 - 0x9fffff are some more esoteric system calls 571 */ 572#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) 573asmlinkage int arm_syscall(int no, struct pt_regs *regs) 574{ 575 siginfo_t info; 576 577 if ((no >> 16) != (__ARM_NR_BASE>> 16)) 578 return bad_syscall(no, regs); 579 580 switch (no & 0xffff) { 581 case 0: /* branch through 0 */ 582 info.si_signo = SIGSEGV; 583 info.si_errno = 0; 584 info.si_code = SEGV_MAPERR; 585 info.si_addr = NULL; 586 587 arm_notify_die("branch through zero", regs, &info, 0, 0); 588 return 0; 589 590 case NR(breakpoint): /* SWI BREAK_POINT */ 591 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 592 ptrace_break(current, regs); 593 return regs->ARM_r0; 594 595 /* 596 * Flush a region from virtual address 'r0' to virtual address 'r1' 597 * _exclusive_. There is no alignment requirement on either address; 598 * user space does not need to know the hardware cache layout. 599 * 600 * r2 contains flags. It should ALWAYS be passed as ZERO until it 601 * is defined to be something else. For now we ignore it, but may 602 * the fires of hell burn in your belly if you break this rule. ;) 603 * 604 * (at a later date, we may want to allow this call to not flush 605 * various aspects of the cache. Passing '0' will guarantee that 606 * everything necessary gets flushed to maintain consistency in 607 * the specified region). 608 */ 609 case NR(cacheflush): 610 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); 611 612 case NR(usr26): 613 if (!(elf_hwcap & HWCAP_26BIT)) 614 break; 615 regs->ARM_cpsr &= ~MODE32_BIT; 616 return regs->ARM_r0; 617 618 case NR(usr32): 619 if (!(elf_hwcap & HWCAP_26BIT)) 620 break; 621 regs->ARM_cpsr |= MODE32_BIT; 622 return regs->ARM_r0; 623 624 case NR(set_tls): 625 set_tls(regs->ARM_r0); 626 return 0; 627 628#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG 629 /* 630 * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. 631 * Return zero in r0 if *MEM was changed or non-zero if no exchange 632 * happened. Also set the user C flag accordingly. 633 * If access permissions have to be fixed up then non-zero is 634 * returned and the operation has to be re-attempted. 635 * 636 * *NOTE*: This is a ghost syscall private to the kernel. Only the 637 * __kuser_cmpxchg code in entry-armv.S should be aware of its 638 * existence. Don't ever use this from user code. 639 */ 640 case NR(cmpxchg): 641 for (;;) { 642 extern void do_DataAbort(unsigned long addr, unsigned int fsr, 643 struct pt_regs *regs); 644 unsigned long val; 645 unsigned long addr = regs->ARM_r2; 646 struct mm_struct *mm = current->mm; 647 pgd_t *pgd; pmd_t *pmd; pte_t *pte; 648 spinlock_t *ptl; 649 650 regs->ARM_cpsr &= ~PSR_C_BIT; 651 down_read(&mm->mmap_sem); 652 pgd = pgd_offset(mm, addr); 653 if (!pgd_present(*pgd)) 654 goto bad_access; 655 pmd = pmd_offset(pgd, addr); 656 if (!pmd_present(*pmd)) 657 goto bad_access; 658 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 659 if (!pte_present(*pte) || !pte_write(*pte) || !pte_dirty(*pte)) { 660 pte_unmap_unlock(pte, ptl); 661 goto bad_access; 662 } 663 val = *(unsigned long *)addr; 664 val -= regs->ARM_r0; 665 if (val == 0) { 666 *(unsigned long *)addr = regs->ARM_r1; 667 regs->ARM_cpsr |= PSR_C_BIT; 668 } 669 pte_unmap_unlock(pte, ptl); 670 up_read(&mm->mmap_sem); 671 return val; 672 673 bad_access: 674 up_read(&mm->mmap_sem); 675 /* simulate a write access fault */ 676 do_DataAbort(addr, 15 + (1 << 11), regs); 677 } 678#endif 679 680 default: 681 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS 682 if not implemented, rather than raising SIGILL. This 683 way the calling program can gracefully determine whether 684 a feature is supported. */ 685 if ((no & 0xffff) <= 0x7ff) 686 return -ENOSYS; 687 break; 688 } 689#ifdef CONFIG_DEBUG_USER 690 /* 691 * experience shows that these seem to indicate that 692 * something catastrophic has happened 693 */ 694 if (user_debug & UDBG_SYSCALL) { 695 pr_err("[%d] %s: arm syscall %d\n", 696 task_pid_nr(current), current->comm, no); 697 dump_instr("", regs); 698 if (user_mode(regs)) { 699 __show_regs(regs); 700 c_backtrace(frame_pointer(regs), processor_mode(regs)); 701 } 702 } 703#endif 704 info.si_signo = SIGILL; 705 info.si_errno = 0; 706 info.si_code = ILL_ILLTRP; 707 info.si_addr = (void __user *)instruction_pointer(regs) - 708 (thumb_mode(regs) ? 2 : 4); 709 710 arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); 711 return 0; 712} 713 714#ifdef CONFIG_TLS_REG_EMUL 715 716/* 717 * We might be running on an ARMv6+ processor which should have the TLS 718 * register but for some reason we can't use it, or maybe an SMP system 719 * using a pre-ARMv6 processor (there are apparently a few prototypes like 720 * that in existence) and therefore access to that register must be 721 * emulated. 722 */ 723 724static int get_tp_trap(struct pt_regs *regs, unsigned int instr) 725{ 726 int reg = (instr >> 12) & 15; 727 if (reg == 15) 728 return 1; 729 regs->uregs[reg] = current_thread_info()->tp_value[0]; 730 regs->ARM_pc += 4; 731 return 0; 732} 733 734static struct undef_hook arm_mrc_hook = { 735 .instr_mask = 0x0fff0fff, 736 .instr_val = 0x0e1d0f70, 737 .cpsr_mask = PSR_T_BIT, 738 .cpsr_val = 0, 739 .fn = get_tp_trap, 740}; 741 742static int __init arm_mrc_hook_init(void) 743{ 744 register_undef_hook(&arm_mrc_hook); 745 return 0; 746} 747 748late_initcall(arm_mrc_hook_init); 749 750#endif 751 752void __bad_xchg(volatile void *ptr, int size) 753{ 754 pr_err("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", 755 __builtin_return_address(0), ptr, size); 756 BUG(); 757} 758EXPORT_SYMBOL(__bad_xchg); 759 760/* 761 * A data abort trap was taken, but we did not handle the instruction. 762 * Try to abort the user program, or panic if it was the kernel. 763 */ 764asmlinkage void 765baddataabort(int code, unsigned long instr, struct pt_regs *regs) 766{ 767 unsigned long addr = instruction_pointer(regs); 768 siginfo_t info; 769 770#ifdef CONFIG_DEBUG_USER 771 if (user_debug & UDBG_BADABORT) { 772 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", 773 task_pid_nr(current), current->comm, code, instr); 774 dump_instr(KERN_ERR, regs); 775 show_pte(current->mm, addr); 776 } 777#endif 778 779 info.si_signo = SIGILL; 780 info.si_errno = 0; 781 info.si_code = ILL_ILLOPC; 782 info.si_addr = (void __user *)addr; 783 784 arm_notify_die("unknown data abort code", regs, &info, instr, 0); 785} 786 787void __readwrite_bug(const char *fn) 788{ 789 pr_err("%s called, but not implemented\n", fn); 790 BUG(); 791} 792EXPORT_SYMBOL(__readwrite_bug); 793 794void __pte_error(const char *file, int line, pte_t pte) 795{ 796 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); 797} 798 799void __pmd_error(const char *file, int line, pmd_t pmd) 800{ 801 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); 802} 803 804void __pgd_error(const char *file, int line, pgd_t pgd) 805{ 806 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); 807} 808 809asmlinkage void __div0(void) 810{ 811 pr_err("Division by zero in kernel.\n"); 812 dump_stack(); 813} 814EXPORT_SYMBOL(__div0); 815 816void abort(void) 817{ 818 BUG(); 819 820 /* if that doesn't kill us, halt */ 821 panic("Oops failed to kill thread"); 822} 823EXPORT_SYMBOL(abort); 824 825void __init trap_init(void) 826{ 827 return; 828} 829 830#ifdef CONFIG_KUSER_HELPERS 831static void __init kuser_init(void *vectors) 832{ 833 extern char __kuser_helper_start[], __kuser_helper_end[]; 834 int kuser_sz = __kuser_helper_end - __kuser_helper_start; 835 836 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); 837 838 /* 839 * vectors + 0xfe0 = __kuser_get_tls 840 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 841 */ 842 if (tls_emu || has_tls_reg) 843 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); 844} 845#else 846static inline void __init kuser_init(void *vectors) 847{ 848} 849#endif 850 851void __init early_trap_init(void *vectors_base) 852{ 853#ifndef CONFIG_CPU_V7M 854 unsigned long vectors = (unsigned long)vectors_base; 855 extern char __stubs_start[], __stubs_end[]; 856 extern char __vectors_start[], __vectors_end[]; 857 unsigned i; 858 859 vectors_page = vectors_base; 860 861 /* 862 * Poison the vectors page with an undefined instruction. This 863 * instruction is chosen to be undefined for both ARM and Thumb 864 * ISAs. The Thumb version is an undefined instruction with a 865 * branch back to the undefined instruction. 866 */ 867 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) 868 ((u32 *)vectors_base)[i] = 0xe7fddef1; 869 870 /* 871 * Copy the vectors, stubs and kuser helpers (in entry-armv.S) 872 * into the vector page, mapped at 0xffff0000, and ensure these 873 * are visible to the instruction stream. 874 */ 875 memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); 876 memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); 877 878 kuser_init(vectors_base); 879 880 flush_icache_range(vectors, vectors + PAGE_SIZE * 2); 881 modify_domain(DOMAIN_USER, DOMAIN_CLIENT); 882#else /* ifndef CONFIG_CPU_V7M */ 883 /* 884 * on V7-M there is no need to copy the vector table to a dedicated 885 * memory area. The address is configurable and so a table in the kernel 886 * image can be used. 887 */ 888#endif 889} 890