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 extern void c_backtrace (unsigned long fp, int pmode);
35 extern void show_pte(struct mm_struct *mm, unsigned long addr);
37 const char *processor_modes[]=
38 { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
39 "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
40 "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
41 "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
44 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
46 #ifdef CONFIG_DEBUG_USER
47 unsigned int user_debug;
49 static int __init user_debug_setup(char *str)
51 get_option(&str, &user_debug);
54 __setup("user_debug=", user_debug_setup);
57 void dump_backtrace_entry(unsigned long where, unsigned long from)
59 #ifdef CONFIG_KALLSYMS
60 printk("[<%08lx>] ", where);
61 print_symbol("(%s) ", where);
62 printk("from [<%08lx>] ", from);
63 print_symbol("(%s)\n", from);
65 printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
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.
74 static int verify_stack(unsigned long sp)
76 if (sp < PAGE_OFFSET || (sp > (unsigned long)high_memory && high_memory != 0))
83 * Dump out the contents of some memory nicely...
85 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
87 unsigned long p = bottom & ~31;
92 * We need to switch to kernel mode so that we can use __get_user
93 * to safely read from kernel space. Note that we now dump the
94 * code first, just in case the backtrace kills us.
99 printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
101 for (p = bottom & ~31; p < top;) {
102 printk("%04lx: ", p & 0xffff);
104 for (i = 0; i < 8; i++, p += 4) {
107 if (p < bottom || p >= top)
110 __get_user(val, (unsigned long *)p);
111 printk("%08x ", val);
120 static void dump_instr(struct pt_regs *regs)
122 unsigned long addr = instruction_pointer(regs);
123 const int thumb = thumb_mode(regs);
124 const int width = thumb ? 4 : 8;
129 * We need to switch to kernel mode so that we can use __get_user
130 * to safely read from kernel space. Note that we now dump the
131 * code first, just in case the backtrace kills us.
137 for (i = -4; i < 1; i++) {
138 unsigned int val, bad;
141 bad = __get_user(val, &((u16 *)addr)[i]);
143 bad = __get_user(val, &((u32 *)addr)[i]);
146 printk(i == 0 ? "(%0*x) " : "%0*x ", width, val);
148 printk("bad PC value.");
157 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
162 printk("Backtrace: ");
165 printk("no frame pointer");
167 } else if (verify_stack(fp)) {
168 printk("invalid frame pointer 0x%08x", fp);
170 } else if (fp < (unsigned long)(tsk->thread_info + 1))
171 printk("frame pointer underflow");
175 c_backtrace(fp, processor_mode(regs));
178 void dump_stack(void)
180 #ifdef CONFIG_DEBUG_ERRORS
185 EXPORT_SYMBOL(dump_stack);
187 void show_stack(struct task_struct *tsk, unsigned long *sp)
195 fp = thread_saved_fp(tsk);
197 asm("mov%? %0, fp" : "=r" (fp));
199 c_backtrace(fp, 0x10);
203 DEFINE_SPINLOCK(die_lock);
206 * This function is protected against re-entrancy.
208 NORET_TYPE void die(const char *str, struct pt_regs *regs, int err)
210 struct task_struct *tsk = current;
211 static int die_counter;
214 spin_lock_irq(&die_lock);
217 printk("Internal error: %s: %x [#%d]\n", str, err, ++die_counter);
219 printk("CPU: %d\n", smp_processor_id());
221 printk("Process %s (pid: %d, stack limit = 0x%p)\n",
222 tsk->comm, tsk->pid, tsk->thread_info + 1);
224 if (!user_mode(regs) || in_interrupt()) {
225 dump_mem("Stack: ", regs->ARM_sp, 8192+(unsigned long)tsk->thread_info);
226 dump_backtrace(regs, tsk);
231 spin_unlock_irq(&die_lock);
235 void die_if_kernel(const char *str, struct pt_regs *regs, int err)
243 static LIST_HEAD(undef_hook);
244 static DEFINE_SPINLOCK(undef_lock);
246 void register_undef_hook(struct undef_hook *hook)
248 spin_lock_irq(&undef_lock);
249 list_add(&hook->node, &undef_hook);
250 spin_unlock_irq(&undef_lock);
253 void unregister_undef_hook(struct undef_hook *hook)
255 spin_lock_irq(&undef_lock);
256 list_del(&hook->node);
257 spin_unlock_irq(&undef_lock);
260 asmlinkage void do_undefinstr(struct pt_regs *regs)
262 unsigned int correction = thumb_mode(regs) ? 2 : 4;
264 struct undef_hook *hook;
269 * According to the ARM ARM, PC is 2 or 4 bytes ahead,
270 * depending whether we're in Thumb mode or not.
271 * Correct this offset.
273 regs->ARM_pc -= correction;
275 pc = (void __user *)instruction_pointer(regs);
276 if (thumb_mode(regs)) {
277 get_user(instr, (u16 __user *)pc);
279 get_user(instr, (u32 __user *)pc);
282 spin_lock_irq(&undef_lock);
283 list_for_each_entry(hook, &undef_hook, node) {
284 if ((instr & hook->instr_mask) == hook->instr_val &&
285 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) {
286 if (hook->fn(regs, instr) == 0) {
287 spin_unlock_irq(&undef_lock);
292 spin_unlock_irq(&undef_lock);
294 #ifdef CONFIG_DEBUG_USER
295 if (user_debug & UDBG_UNDEFINED) {
296 printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
297 current->comm, current->pid, pc);
302 current->thread.error_code = 0;
303 current->thread.trap_no = 6;
305 info.si_signo = SIGILL;
307 info.si_code = ILL_ILLOPC;
310 force_sig_info(SIGILL, &info, current);
312 die_if_kernel("Oops - undefined instruction", regs, 0);
315 asmlinkage void do_unexp_fiq (struct pt_regs *regs)
317 #ifndef CONFIG_IGNORE_FIQ
318 printk("Hmm. Unexpected FIQ received, but trying to continue\n");
319 printk("You may have a hardware problem...\n");
324 * bad_mode handles the impossible case in the vectors. If you see one of
325 * these, then it's extremely serious, and could mean you have buggy hardware.
326 * It never returns, and never tries to sync. We hope that we can at least
327 * dump out some state information...
329 asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)
333 printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
334 handler[reason], processor_modes[proc_mode]);
336 die("Oops - bad mode", regs, 0);
341 static int bad_syscall(int n, struct pt_regs *regs)
343 struct thread_info *thread = current_thread_info();
346 if (current->personality != PER_LINUX && thread->exec_domain->handler) {
347 thread->exec_domain->handler(n, regs);
351 #ifdef CONFIG_DEBUG_USER
352 if (user_debug & UDBG_SYSCALL) {
353 printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
354 current->pid, current->comm, n);
359 info.si_signo = SIGILL;
361 info.si_code = ILL_ILLTRP;
362 info.si_addr = (void __user *)instruction_pointer(regs) -
363 (thumb_mode(regs) ? 2 : 4);
365 force_sig_info(SIGILL, &info, current);
366 die_if_kernel("Oops - bad syscall", regs, n);
371 do_cache_op(unsigned long start, unsigned long end, int flags)
373 struct vm_area_struct *vma;
375 if (end < start || flags)
378 vma = find_vma(current->active_mm, start);
379 if (vma && vma->vm_start < end) {
380 if (start < vma->vm_start)
381 start = vma->vm_start;
382 if (end > vma->vm_end)
385 flush_cache_user_range(vma, start, end);
390 * Handle all unrecognised system calls.
391 * 0x9f0000 - 0x9fffff are some more esoteric system calls
393 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
394 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
396 struct thread_info *thread = current_thread_info();
399 if ((no >> 16) != 0x9f)
400 return bad_syscall(no, regs);
402 switch (no & 0xffff) {
403 case 0: /* branch through 0 */
404 info.si_signo = SIGSEGV;
406 info.si_code = SEGV_MAPERR;
409 force_sig_info(SIGSEGV, &info, current);
411 die_if_kernel("branch through zero", regs, 0);
414 case NR(breakpoint): /* SWI BREAK_POINT */
415 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
416 ptrace_break(current, regs);
420 * Flush a region from virtual address 'r0' to virtual address 'r1'
421 * _exclusive_. There is no alignment requirement on either address;
422 * user space does not need to know the hardware cache layout.
424 * r2 contains flags. It should ALWAYS be passed as ZERO until it
425 * is defined to be something else. For now we ignore it, but may
426 * the fires of hell burn in your belly if you break this rule. ;)
428 * (at a later date, we may want to allow this call to not flush
429 * various aspects of the cache. Passing '0' will guarantee that
430 * everything necessary gets flushed to maintain consistency in
431 * the specified region).
434 do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
438 if (!(elf_hwcap & HWCAP_26BIT))
440 regs->ARM_cpsr &= ~MODE32_BIT;
444 if (!(elf_hwcap & HWCAP_26BIT))
446 regs->ARM_cpsr |= MODE32_BIT;
450 thread->tp_value = regs->ARM_r0;
452 * Our user accessible TLS ptr is located at 0xffff0ffc.
453 * On SMP read access to this address must raise a fault
454 * and be emulated from the data abort handler.
457 *((unsigned long *)0xffff0ffc) = thread->tp_value;
461 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
462 if not implemented, rather than raising SIGILL. This
463 way the calling program can gracefully determine whether
464 a feature is supported. */
469 #ifdef CONFIG_DEBUG_USER
471 * experience shows that these seem to indicate that
472 * something catastrophic has happened
474 if (user_debug & UDBG_SYSCALL) {
475 printk("[%d] %s: arm syscall %d\n",
476 current->pid, current->comm, no);
478 if (user_mode(regs)) {
480 c_backtrace(regs->ARM_fp, processor_mode(regs));
484 info.si_signo = SIGILL;
486 info.si_code = ILL_ILLTRP;
487 info.si_addr = (void __user *)instruction_pointer(regs) -
488 (thumb_mode(regs) ? 2 : 4);
490 force_sig_info(SIGILL, &info, current);
491 die_if_kernel("Oops - bad syscall(2)", regs, no);
495 void __bad_xchg(volatile void *ptr, int size)
497 printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
498 __builtin_return_address(0), ptr, size);
501 EXPORT_SYMBOL(__bad_xchg);
504 * A data abort trap was taken, but we did not handle the instruction.
505 * Try to abort the user program, or panic if it was the kernel.
508 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
510 unsigned long addr = instruction_pointer(regs);
513 #ifdef CONFIG_DEBUG_USER
514 if (user_debug & UDBG_BADABORT) {
515 printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
516 current->pid, current->comm, code, instr);
518 show_pte(current->mm, addr);
522 info.si_signo = SIGILL;
524 info.si_code = ILL_ILLOPC;
525 info.si_addr = (void __user *)addr;
527 force_sig_info(SIGILL, &info, current);
528 die_if_kernel("unknown data abort code", regs, instr);
531 volatile void __bug(const char *file, int line, void *data)
533 printk(KERN_CRIT"kernel BUG at %s:%d!", file, line);
535 printk(" - extra data = %p", data);
539 EXPORT_SYMBOL(__bug);
541 void __readwrite_bug(const char *fn)
543 printk("%s called, but not implemented\n", fn);
546 EXPORT_SYMBOL(__readwrite_bug);
548 void __pte_error(const char *file, int line, unsigned long val)
550 printk("%s:%d: bad pte %08lx.\n", file, line, val);
553 void __pmd_error(const char *file, int line, unsigned long val)
555 printk("%s:%d: bad pmd %08lx.\n", file, line, val);
558 void __pgd_error(const char *file, int line, unsigned long val)
560 printk("%s:%d: bad pgd %08lx.\n", file, line, val);
563 asmlinkage void __div0(void)
565 printk("Division by zero in kernel.\n");
568 EXPORT_SYMBOL(__div0);
574 /* if that doesn't kill us, halt */
575 panic("Oops failed to kill thread");
577 EXPORT_SYMBOL(abort);
579 void __init trap_init(void)
581 extern void __trap_init(void);
584 flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
585 modify_domain(DOMAIN_USER, DOMAIN_CLIENT);