2 * linux/arch/arm/kernel/traps.c
4 * Copyright (C) 1995-2002 Russell King
5 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
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.
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.
15 #include <linux/config.h>
16 #include <linux/module.h>
17 #include <linux/signal.h>
18 #include <linux/spinlock.h>
19 #include <linux/personality.h>
20 #include <linux/ptrace.h>
21 #include <linux/kallsyms.h>
22 #include <linux/init.h>
24 #include <asm/atomic.h>
25 #include <asm/cacheflush.h>
27 #include <asm/system.h>
28 #include <asm/uaccess.h>
29 #include <asm/unistd.h>
30 #include <asm/traps.h>
34 const char *processor_modes[]=
35 { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
36 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
37 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
38 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
41 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
43 #ifdef CONFIG_DEBUG_USER
44 unsigned int user_debug;
46 static int __init user_debug_setup(char *str)
48 get_option(&str, &user_debug);
51 __setup("user_debug=", user_debug_setup);
54 void dump_backtrace_entry(unsigned long where, unsigned long from)
56 #ifdef CONFIG_KALLSYMS
57 printk("[<%08lx>] ", where);
58 print_symbol("(%s) ", where);
59 printk("from [<%08lx>] ", from);
60 print_symbol("(%s)\n", from);
62 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
67 * Stack pointers should always be within the kernels view of
68 * physical memory. If it is not there, then we can't dump
69 * out any information relating to the stack.
71 static int verify_stack(unsigned long sp)
73 if (sp < PAGE_OFFSET || (sp > (unsigned long)high_memory && high_memory != 0))
80 * Dump out the contents of some memory nicely...
82 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
84 unsigned long p = bottom & ~31;
89 * We need to switch to kernel mode so that we can use __get_user
90 * to safely read from kernel space. Note that we now dump the
91 * code first, just in case the backtrace kills us.
96 printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
98 for (p = bottom & ~31; p < top;) {
99 printk("%04lx: ", p & 0xffff);
101 for (i = 0; i < 8; i++, p += 4) {
104 if (p < bottom || p >= top)
107 __get_user(val, (unsigned long *)p);
108 printk("%08x ", val);
117 static void dump_instr(struct pt_regs *regs)
119 unsigned long addr = instruction_pointer(regs);
120 const int thumb = thumb_mode(regs);
121 const int width = thumb ? 4 : 8;
126 * We need to switch to kernel mode so that we can use __get_user
127 * to safely read from kernel space. Note that we now dump the
128 * code first, just in case the backtrace kills us.
134 for (i = -4; i < 1; i++) {
135 unsigned int val, bad;
138 bad = __get_user(val, &((u16 *)addr)[i]);
140 bad = __get_user(val, &((u32 *)addr)[i]);
143 printk(i == 0 ? "(%0*x) " : "%0*x ", width, val);
145 printk("bad PC value.");
154 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
159 printk("Backtrace: ");
162 printk("no frame pointer");
164 } else if (verify_stack(fp)) {
165 printk("invalid frame pointer 0x%08x", fp);
167 } else if (fp < (unsigned long)(tsk->thread_info + 1))
168 printk("frame pointer underflow");
172 c_backtrace(fp, processor_mode(regs));
175 void dump_stack(void)
177 #ifdef CONFIG_DEBUG_ERRORS
182 EXPORT_SYMBOL(dump_stack);
184 void show_stack(struct task_struct *tsk, unsigned long *sp)
192 fp = thread_saved_fp(tsk);
194 asm("mov%? %0, fp" : "=r" (fp));
196 c_backtrace(fp, 0x10);
200 DEFINE_SPINLOCK(die_lock);
203 * This function is protected against re-entrancy.
205 NORET_TYPE void die(const char *str, struct pt_regs *regs, int err)
207 struct task_struct *tsk = current;
208 static int die_counter;
211 spin_lock_irq(&die_lock);
214 printk("Internal error: %s: %x [#%d]\n", str, err, ++die_counter);
217 printk("Process %s (pid: %d, stack limit = 0x%p)\n",
218 tsk->comm, tsk->pid, tsk->thread_info + 1);
220 if (!user_mode(regs) || in_interrupt()) {
221 dump_mem("Stack: ", regs->ARM_sp,
222 THREAD_SIZE + (unsigned long)tsk->thread_info);
223 dump_backtrace(regs, tsk);
228 spin_unlock_irq(&die_lock);
232 void die_if_kernel(const char *str, struct pt_regs *regs, int err)
240 static void notify_die(const char *str, struct pt_regs *regs, siginfo_t *info,
241 unsigned long err, unsigned long trap)
243 if (user_mode(regs)) {
244 current->thread.error_code = err;
245 current->thread.trap_no = trap;
247 force_sig_info(info->si_signo, info, current);
253 static LIST_HEAD(undef_hook);
254 static DEFINE_SPINLOCK(undef_lock);
256 void register_undef_hook(struct undef_hook *hook)
258 spin_lock_irq(&undef_lock);
259 list_add(&hook->node, &undef_hook);
260 spin_unlock_irq(&undef_lock);
263 void unregister_undef_hook(struct undef_hook *hook)
265 spin_lock_irq(&undef_lock);
266 list_del(&hook->node);
267 spin_unlock_irq(&undef_lock);
270 asmlinkage void do_undefinstr(struct pt_regs *regs)
272 unsigned int correction = thumb_mode(regs) ? 2 : 4;
274 struct undef_hook *hook;
279 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
280 * depending whether we're in Thumb mode or not.
281 * Correct this offset.
283 regs->ARM_pc -= correction;
285 pc = (void __user *)instruction_pointer(regs);
286 if (thumb_mode(regs)) {
287 get_user(instr, (u16 __user *)pc);
289 get_user(instr, (u32 __user *)pc);
292 spin_lock_irq(&undef_lock);
293 list_for_each_entry(hook, &undef_hook, node) {
294 if ((instr & hook->instr_mask) == hook->instr_val &&
295 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) {
296 if (hook->fn(regs, instr) == 0) {
297 spin_unlock_irq(&undef_lock);
302 spin_unlock_irq(&undef_lock);
304 #ifdef CONFIG_DEBUG_USER
305 if (user_debug & UDBG_UNDEFINED) {
306 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
307 current->comm, current->pid, pc);
312 info.si_signo = SIGILL;
314 info.si_code = ILL_ILLOPC;
317 notify_die("Oops - undefined instruction", regs, &info, 0, 6);
320 asmlinkage void do_unexp_fiq (struct pt_regs *regs)
322 #ifndef CONFIG_IGNORE_FIQ
323 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
324 printk("You may have a hardware problem...\n");
329 * bad_mode handles the impossible case in the vectors. If you see one of
330 * these, then it's extremely serious, and could mean you have buggy hardware.
331 * It never returns, and never tries to sync. We hope that we can at least
332 * dump out some state information...
334 asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)
338 printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
339 handler[reason], processor_modes[proc_mode]);
341 die("Oops - bad mode", regs, 0);
346 static int bad_syscall(int n, struct pt_regs *regs)
348 struct thread_info *thread = current_thread_info();
351 if (current->personality != PER_LINUX && thread->exec_domain->handler) {
352 thread->exec_domain->handler(n, regs);
356 #ifdef CONFIG_DEBUG_USER
357 if (user_debug & UDBG_SYSCALL) {
358 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
359 current->pid, current->comm, n);
364 info.si_signo = SIGILL;
366 info.si_code = ILL_ILLTRP;
367 info.si_addr = (void __user *)instruction_pointer(regs) -
368 (thumb_mode(regs) ? 2 : 4);
370 notify_die("Oops - bad syscall", regs, &info, n, 0);
376 do_cache_op(unsigned long start, unsigned long end, int flags)
378 struct vm_area_struct *vma;
380 if (end < start || flags)
383 vma = find_vma(current->active_mm, start);
384 if (vma && vma->vm_start < end) {
385 if (start < vma->vm_start)
386 start = vma->vm_start;
387 if (end > vma->vm_end)
390 flush_cache_user_range(vma, start, end);
395 * Handle all unrecognised system calls.
396 * 0x9f0000 - 0x9fffff are some more esoteric system calls
398 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
399 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
401 struct thread_info *thread = current_thread_info();
404 if ((no >> 16) != 0x9f)
405 return bad_syscall(no, regs);
407 switch (no & 0xffff) {
408 case 0: /* branch through 0 */
409 info.si_signo = SIGSEGV;
411 info.si_code = SEGV_MAPERR;
414 notify_die("branch through zero", regs, &info, 0, 0);
417 case NR(breakpoint): /* SWI BREAK_POINT */
418 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
419 ptrace_break(current, regs);
423 * Flush a region from virtual address 'r0' to virtual address 'r1'
424 * _exclusive_. There is no alignment requirement on either address;
425 * user space does not need to know the hardware cache layout.
427 * r2 contains flags. It should ALWAYS be passed as ZERO until it
428 * is defined to be something else. For now we ignore it, but may
429 * the fires of hell burn in your belly if you break this rule. ;)
431 * (at a later date, we may want to allow this call to not flush
432 * various aspects of the cache. Passing '0' will guarantee that
433 * everything necessary gets flushed to maintain consistency in
434 * the specified region).
437 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
441 if (!(elf_hwcap & HWCAP_26BIT))
443 regs->ARM_cpsr &= ~MODE32_BIT;
447 if (!(elf_hwcap & HWCAP_26BIT))
449 regs->ARM_cpsr |= MODE32_BIT;
453 thread->tp_value = regs->ARM_r0;
454 #if defined(CONFIG_HAS_TLS_REG)
455 asm ("mcr p15, 0, %0, c13, c0, 3" : : "r" (regs->ARM_r0) );
456 #elif !defined(CONFIG_TLS_REG_EMUL)
458 * User space must never try to access this directly.
459 * Expect your app to break eventually if you do so.
460 * The user helper at 0xffff0fe0 must be used instead.
461 * (see entry-armv.S for details)
463 *((unsigned int *)0xffff0ff0) = regs->ARM_r0;
468 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
469 if not implemented, rather than raising SIGILL. This
470 way the calling program can gracefully determine whether
471 a feature is supported. */
476 #ifdef CONFIG_DEBUG_USER
478 * experience shows that these seem to indicate that
479 * something catastrophic has happened
481 if (user_debug & UDBG_SYSCALL) {
482 printk("[%d] %s: arm syscall %d\n",
483 current->pid, current->comm, no);
485 if (user_mode(regs)) {
487 c_backtrace(regs->ARM_fp, processor_mode(regs));
491 info.si_signo = SIGILL;
493 info.si_code = ILL_ILLTRP;
494 info.si_addr = (void __user *)instruction_pointer(regs) -
495 (thumb_mode(regs) ? 2 : 4);
497 notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
501 #ifdef CONFIG_TLS_REG_EMUL
504 * We might be running on an ARMv6+ processor which should have the TLS
505 * register but for some reason we can't use it, or maybe an SMP system
506 * using a pre-ARMv6 processor (there are apparently a few prototypes like
507 * that in existence) and therefore access to that register must be
511 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
513 int reg = (instr >> 12) & 15;
516 regs->uregs[reg] = current_thread_info()->tp_value;
521 static struct undef_hook arm_mrc_hook = {
522 .instr_mask = 0x0fff0fff,
523 .instr_val = 0x0e1d0f70,
524 .cpsr_mask = PSR_T_BIT,
529 static int __init arm_mrc_hook_init(void)
531 register_undef_hook(&arm_mrc_hook);
535 late_initcall(arm_mrc_hook_init);
539 void __bad_xchg(volatile void *ptr, int size)
541 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
542 __builtin_return_address(0), ptr, size);
545 EXPORT_SYMBOL(__bad_xchg);
548 * A data abort trap was taken, but we did not handle the instruction.
549 * Try to abort the user program, or panic if it was the kernel.
552 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
554 unsigned long addr = instruction_pointer(regs);
557 #ifdef CONFIG_DEBUG_USER
558 if (user_debug & UDBG_BADABORT) {
559 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
560 current->pid, current->comm, code, instr);
562 show_pte(current->mm, addr);
566 info.si_signo = SIGILL;
568 info.si_code = ILL_ILLOPC;
569 info.si_addr = (void __user *)addr;
571 notify_die("unknown data abort code", regs, &info, instr, 0);
574 volatile void __bug(const char *file, int line, void *data)
576 printk(KERN_CRIT"kernel BUG at %s:%d!", file, line);
578 printk(" - extra data = %p", data);
582 EXPORT_SYMBOL(__bug);
584 void __readwrite_bug(const char *fn)
586 printk("%s called, but not implemented\n", fn);
589 EXPORT_SYMBOL(__readwrite_bug);
591 void __pte_error(const char *file, int line, unsigned long val)
593 printk("%s:%d: bad pte %08lx.\n", file, line, val);
596 void __pmd_error(const char *file, int line, unsigned long val)
598 printk("%s:%d: bad pmd %08lx.\n", file, line, val);
601 void __pgd_error(const char *file, int line, unsigned long val)
603 printk("%s:%d: bad pgd %08lx.\n", file, line, val);
606 asmlinkage void __div0(void)
608 printk("Division by zero in kernel.\n");
611 EXPORT_SYMBOL(__div0);
617 /* if that doesn't kill us, halt */
618 panic("Oops failed to kill thread");
620 EXPORT_SYMBOL(abort);
622 void __init trap_init(void)
624 extern char __stubs_start[], __stubs_end[];
625 extern char __vectors_start[], __vectors_end[];
626 extern char __kuser_helper_start[], __kuser_helper_end[];
627 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
630 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
631 * into the vector page, mapped at 0xffff0000, and ensure these
632 * are visible to the instruction stream.
634 memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start);
635 memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start);
636 memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz);
637 flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
638 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);