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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/kernel/traps.c | |
3 | * | |
4 | * Copyright (C) 1995-2002 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/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> | |
23 | ||
24 | #include <asm/atomic.h> | |
25 | #include <asm/cacheflush.h> | |
26 | #include <asm/io.h> | |
27 | #include <asm/system.h> | |
28 | #include <asm/uaccess.h> | |
29 | #include <asm/unistd.h> | |
30 | #include <asm/traps.h> | |
31 | ||
32 | #include "ptrace.h" | |
33 | ||
34 | extern void c_backtrace (unsigned long fp, int pmode); | |
35 | extern void show_pte(struct mm_struct *mm, unsigned long addr); | |
36 | ||
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" | |
42 | }; | |
43 | ||
44 | static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; | |
45 | ||
46 | #ifdef CONFIG_DEBUG_USER | |
47 | unsigned int user_debug; | |
48 | ||
49 | static int __init user_debug_setup(char *str) | |
50 | { | |
51 | get_option(&str, &user_debug); | |
52 | return 1; | |
53 | } | |
54 | __setup("user_debug=", user_debug_setup); | |
55 | #endif | |
56 | ||
57 | void dump_backtrace_entry(unsigned long where, unsigned long from) | |
58 | { | |
59 | #ifdef CONFIG_KALLSYMS | |
60 | printk("[<%08lx>] ", where); | |
61 | print_symbol("(%s) ", where); | |
62 | printk("from [<%08lx>] ", from); | |
63 | print_symbol("(%s)\n", from); | |
64 | #else | |
65 | printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); | |
66 | #endif | |
67 | } | |
68 | ||
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 | */ | |
74 | static int verify_stack(unsigned long sp) | |
75 | { | |
76 | if (sp < PAGE_OFFSET || (sp > (unsigned long)high_memory && high_memory != 0)) | |
77 | return -EFAULT; | |
78 | ||
79 | return 0; | |
80 | } | |
81 | ||
82 | /* | |
83 | * Dump out the contents of some memory nicely... | |
84 | */ | |
85 | static void dump_mem(const char *str, unsigned long bottom, unsigned long top) | |
86 | { | |
87 | unsigned long p = bottom & ~31; | |
88 | mm_segment_t fs; | |
89 | int i; | |
90 | ||
91 | /* | |
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. | |
95 | */ | |
96 | fs = get_fs(); | |
97 | set_fs(KERNEL_DS); | |
98 | ||
99 | printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top); | |
100 | ||
101 | for (p = bottom & ~31; p < top;) { | |
102 | printk("%04lx: ", p & 0xffff); | |
103 | ||
104 | for (i = 0; i < 8; i++, p += 4) { | |
105 | unsigned int val; | |
106 | ||
107 | if (p < bottom || p >= top) | |
108 | printk(" "); | |
109 | else { | |
110 | __get_user(val, (unsigned long *)p); | |
111 | printk("%08x ", val); | |
112 | } | |
113 | } | |
114 | printk ("\n"); | |
115 | } | |
116 | ||
117 | set_fs(fs); | |
118 | } | |
119 | ||
120 | static void dump_instr(struct pt_regs *regs) | |
121 | { | |
122 | unsigned long addr = instruction_pointer(regs); | |
123 | const int thumb = thumb_mode(regs); | |
124 | const int width = thumb ? 4 : 8; | |
125 | mm_segment_t fs; | |
126 | int i; | |
127 | ||
128 | /* | |
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. | |
132 | */ | |
133 | fs = get_fs(); | |
134 | set_fs(KERNEL_DS); | |
135 | ||
136 | printk("Code: "); | |
137 | for (i = -4; i < 1; i++) { | |
138 | unsigned int val, bad; | |
139 | ||
140 | if (thumb) | |
141 | bad = __get_user(val, &((u16 *)addr)[i]); | |
142 | else | |
143 | bad = __get_user(val, &((u32 *)addr)[i]); | |
144 | ||
145 | if (!bad) | |
146 | printk(i == 0 ? "(%0*x) " : "%0*x ", width, val); | |
147 | else { | |
148 | printk("bad PC value."); | |
149 | break; | |
150 | } | |
151 | } | |
152 | printk("\n"); | |
153 | ||
154 | set_fs(fs); | |
155 | } | |
156 | ||
157 | static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | |
158 | { | |
159 | unsigned int fp; | |
160 | int ok = 1; | |
161 | ||
162 | printk("Backtrace: "); | |
163 | fp = regs->ARM_fp; | |
164 | if (!fp) { | |
165 | printk("no frame pointer"); | |
166 | ok = 0; | |
167 | } else if (verify_stack(fp)) { | |
168 | printk("invalid frame pointer 0x%08x", fp); | |
169 | ok = 0; | |
170 | } else if (fp < (unsigned long)(tsk->thread_info + 1)) | |
171 | printk("frame pointer underflow"); | |
172 | printk("\n"); | |
173 | ||
174 | if (ok) | |
175 | c_backtrace(fp, processor_mode(regs)); | |
176 | } | |
177 | ||
178 | void dump_stack(void) | |
179 | { | |
180 | #ifdef CONFIG_DEBUG_ERRORS | |
181 | __backtrace(); | |
182 | #endif | |
183 | } | |
184 | ||
185 | EXPORT_SYMBOL(dump_stack); | |
186 | ||
187 | void show_stack(struct task_struct *tsk, unsigned long *sp) | |
188 | { | |
189 | unsigned long fp; | |
190 | ||
191 | if (!tsk) | |
192 | tsk = current; | |
193 | ||
194 | if (tsk != current) | |
195 | fp = thread_saved_fp(tsk); | |
196 | else | |
197 | asm("mov%? %0, fp" : "=r" (fp)); | |
198 | ||
199 | c_backtrace(fp, 0x10); | |
200 | barrier(); | |
201 | } | |
202 | ||
203 | DEFINE_SPINLOCK(die_lock); | |
204 | ||
205 | /* | |
206 | * This function is protected against re-entrancy. | |
207 | */ | |
208 | NORET_TYPE void die(const char *str, struct pt_regs *regs, int err) | |
209 | { | |
210 | struct task_struct *tsk = current; | |
211 | static int die_counter; | |
212 | ||
213 | console_verbose(); | |
214 | spin_lock_irq(&die_lock); | |
215 | bust_spinlocks(1); | |
216 | ||
217 | printk("Internal error: %s: %x [#%d]\n", str, err, ++die_counter); | |
218 | print_modules(); | |
219 | printk("CPU: %d\n", smp_processor_id()); | |
220 | show_regs(regs); | |
221 | printk("Process %s (pid: %d, stack limit = 0x%p)\n", | |
222 | tsk->comm, tsk->pid, tsk->thread_info + 1); | |
223 | ||
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); | |
227 | dump_instr(regs); | |
228 | } | |
229 | ||
230 | bust_spinlocks(0); | |
231 | spin_unlock_irq(&die_lock); | |
232 | do_exit(SIGSEGV); | |
233 | } | |
234 | ||
235 | void die_if_kernel(const char *str, struct pt_regs *regs, int err) | |
236 | { | |
237 | if (user_mode(regs)) | |
238 | return; | |
239 | ||
240 | die(str, regs, err); | |
241 | } | |
242 | ||
243 | static void notify_die(const char *str, struct pt_regs *regs, siginfo_t *info, | |
244 | unsigned long err, unsigned long trap) | |
245 | { | |
246 | if (user_mode(regs)) { | |
247 | current->thread.error_code = err; | |
248 | current->thread.trap_no = trap; | |
249 | ||
250 | force_sig_info(info->si_signo, info, current); | |
251 | } else { | |
252 | die(str, regs, err); | |
253 | } | |
254 | } | |
255 | ||
256 | static LIST_HEAD(undef_hook); | |
257 | static DEFINE_SPINLOCK(undef_lock); | |
258 | ||
259 | void register_undef_hook(struct undef_hook *hook) | |
260 | { | |
261 | spin_lock_irq(&undef_lock); | |
262 | list_add(&hook->node, &undef_hook); | |
263 | spin_unlock_irq(&undef_lock); | |
264 | } | |
265 | ||
266 | void unregister_undef_hook(struct undef_hook *hook) | |
267 | { | |
268 | spin_lock_irq(&undef_lock); | |
269 | list_del(&hook->node); | |
270 | spin_unlock_irq(&undef_lock); | |
271 | } | |
272 | ||
273 | asmlinkage void do_undefinstr(struct pt_regs *regs) | |
274 | { | |
275 | unsigned int correction = thumb_mode(regs) ? 2 : 4; | |
276 | unsigned int instr; | |
277 | struct undef_hook *hook; | |
278 | siginfo_t info; | |
279 | void __user *pc; | |
280 | ||
281 | /* | |
282 | * According to the ARM ARM, PC is 2 or 4 bytes ahead, | |
283 | * depending whether we're in Thumb mode or not. | |
284 | * Correct this offset. | |
285 | */ | |
286 | regs->ARM_pc -= correction; | |
287 | ||
288 | pc = (void __user *)instruction_pointer(regs); | |
289 | if (thumb_mode(regs)) { | |
290 | get_user(instr, (u16 __user *)pc); | |
291 | } else { | |
292 | get_user(instr, (u32 __user *)pc); | |
293 | } | |
294 | ||
295 | spin_lock_irq(&undef_lock); | |
296 | list_for_each_entry(hook, &undef_hook, node) { | |
297 | if ((instr & hook->instr_mask) == hook->instr_val && | |
298 | (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) { | |
299 | if (hook->fn(regs, instr) == 0) { | |
300 | spin_unlock_irq(&undef_lock); | |
301 | return; | |
302 | } | |
303 | } | |
304 | } | |
305 | spin_unlock_irq(&undef_lock); | |
306 | ||
307 | #ifdef CONFIG_DEBUG_USER | |
308 | if (user_debug & UDBG_UNDEFINED) { | |
309 | printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", | |
310 | current->comm, current->pid, pc); | |
311 | dump_instr(regs); | |
312 | } | |
313 | #endif | |
314 | ||
315 | info.si_signo = SIGILL; | |
316 | info.si_errno = 0; | |
317 | info.si_code = ILL_ILLOPC; | |
318 | info.si_addr = pc; | |
319 | ||
320 | notify_die("Oops - undefined instruction", regs, &info, 0, 6); | |
321 | } | |
322 | ||
323 | asmlinkage void do_unexp_fiq (struct pt_regs *regs) | |
324 | { | |
325 | #ifndef CONFIG_IGNORE_FIQ | |
326 | printk("Hmm. Unexpected FIQ received, but trying to continue\n"); | |
327 | printk("You may have a hardware problem...\n"); | |
328 | #endif | |
329 | } | |
330 | ||
331 | /* | |
332 | * bad_mode handles the impossible case in the vectors. If you see one of | |
333 | * these, then it's extremely serious, and could mean you have buggy hardware. | |
334 | * It never returns, and never tries to sync. We hope that we can at least | |
335 | * dump out some state information... | |
336 | */ | |
337 | asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode) | |
338 | { | |
339 | console_verbose(); | |
340 | ||
341 | printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n", | |
342 | handler[reason], processor_modes[proc_mode]); | |
343 | ||
344 | die("Oops - bad mode", regs, 0); | |
345 | local_irq_disable(); | |
346 | panic("bad mode"); | |
347 | } | |
348 | ||
349 | static int bad_syscall(int n, struct pt_regs *regs) | |
350 | { | |
351 | struct thread_info *thread = current_thread_info(); | |
352 | siginfo_t info; | |
353 | ||
354 | if (current->personality != PER_LINUX && thread->exec_domain->handler) { | |
355 | thread->exec_domain->handler(n, regs); | |
356 | return regs->ARM_r0; | |
357 | } | |
358 | ||
359 | #ifdef CONFIG_DEBUG_USER | |
360 | if (user_debug & UDBG_SYSCALL) { | |
361 | printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n", | |
362 | current->pid, current->comm, n); | |
363 | dump_instr(regs); | |
364 | } | |
365 | #endif | |
366 | ||
367 | info.si_signo = SIGILL; | |
368 | info.si_errno = 0; | |
369 | info.si_code = ILL_ILLTRP; | |
370 | info.si_addr = (void __user *)instruction_pointer(regs) - | |
371 | (thumb_mode(regs) ? 2 : 4); | |
372 | ||
373 | notify_die("Oops - bad syscall", regs, &info, n, 0); | |
374 | ||
375 | return regs->ARM_r0; | |
376 | } | |
377 | ||
378 | static inline void | |
379 | do_cache_op(unsigned long start, unsigned long end, int flags) | |
380 | { | |
381 | struct vm_area_struct *vma; | |
382 | ||
383 | if (end < start || flags) | |
384 | return; | |
385 | ||
386 | vma = find_vma(current->active_mm, start); | |
387 | if (vma && vma->vm_start < end) { | |
388 | if (start < vma->vm_start) | |
389 | start = vma->vm_start; | |
390 | if (end > vma->vm_end) | |
391 | end = vma->vm_end; | |
392 | ||
393 | flush_cache_user_range(vma, start, end); | |
394 | } | |
395 | } | |
396 | ||
397 | /* | |
398 | * Handle all unrecognised system calls. | |
399 | * 0x9f0000 - 0x9fffff are some more esoteric system calls | |
400 | */ | |
401 | #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) | |
402 | asmlinkage int arm_syscall(int no, struct pt_regs *regs) | |
403 | { | |
404 | struct thread_info *thread = current_thread_info(); | |
405 | siginfo_t info; | |
406 | ||
407 | if ((no >> 16) != 0x9f) | |
408 | return bad_syscall(no, regs); | |
409 | ||
410 | switch (no & 0xffff) { | |
411 | case 0: /* branch through 0 */ | |
412 | info.si_signo = SIGSEGV; | |
413 | info.si_errno = 0; | |
414 | info.si_code = SEGV_MAPERR; | |
415 | info.si_addr = NULL; | |
416 | ||
417 | notify_die("branch through zero", regs, &info, 0, 0); | |
418 | return 0; | |
419 | ||
420 | case NR(breakpoint): /* SWI BREAK_POINT */ | |
421 | regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; | |
422 | ptrace_break(current, regs); | |
423 | return regs->ARM_r0; | |
424 | ||
425 | /* | |
426 | * Flush a region from virtual address 'r0' to virtual address 'r1' | |
427 | * _exclusive_. There is no alignment requirement on either address; | |
428 | * user space does not need to know the hardware cache layout. | |
429 | * | |
430 | * r2 contains flags. It should ALWAYS be passed as ZERO until it | |
431 | * is defined to be something else. For now we ignore it, but may | |
432 | * the fires of hell burn in your belly if you break this rule. ;) | |
433 | * | |
434 | * (at a later date, we may want to allow this call to not flush | |
435 | * various aspects of the cache. Passing '0' will guarantee that | |
436 | * everything necessary gets flushed to maintain consistency in | |
437 | * the specified region). | |
438 | */ | |
439 | case NR(cacheflush): | |
440 | do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); | |
441 | return 0; | |
442 | ||
443 | case NR(usr26): | |
444 | if (!(elf_hwcap & HWCAP_26BIT)) | |
445 | break; | |
446 | regs->ARM_cpsr &= ~MODE32_BIT; | |
447 | return regs->ARM_r0; | |
448 | ||
449 | case NR(usr32): | |
450 | if (!(elf_hwcap & HWCAP_26BIT)) | |
451 | break; | |
452 | regs->ARM_cpsr |= MODE32_BIT; | |
453 | return regs->ARM_r0; | |
454 | ||
455 | case NR(set_tls): | |
456 | thread->tp_value = regs->ARM_r0; | |
457 | /* | |
458 | * Our user accessible TLS ptr is located at 0xffff0ffc. | |
459 | * On SMP read access to this address must raise a fault | |
460 | * and be emulated from the data abort handler. | |
461 | * m | |
462 | */ | |
463 | *((unsigned long *)0xffff0ffc) = thread->tp_value; | |
464 | return 0; | |
465 | ||
466 | default: | |
467 | /* Calls 9f00xx..9f07ff are defined to return -ENOSYS | |
468 | if not implemented, rather than raising SIGILL. This | |
469 | way the calling program can gracefully determine whether | |
470 | a feature is supported. */ | |
471 | if (no <= 0x7ff) | |
472 | return -ENOSYS; | |
473 | break; | |
474 | } | |
475 | #ifdef CONFIG_DEBUG_USER | |
476 | /* | |
477 | * experience shows that these seem to indicate that | |
478 | * something catastrophic has happened | |
479 | */ | |
480 | if (user_debug & UDBG_SYSCALL) { | |
481 | printk("[%d] %s: arm syscall %d\n", | |
482 | current->pid, current->comm, no); | |
483 | dump_instr(regs); | |
484 | if (user_mode(regs)) { | |
485 | show_regs(regs); | |
486 | c_backtrace(regs->ARM_fp, processor_mode(regs)); | |
487 | } | |
488 | } | |
489 | #endif | |
490 | info.si_signo = SIGILL; | |
491 | info.si_errno = 0; | |
492 | info.si_code = ILL_ILLTRP; | |
493 | info.si_addr = (void __user *)instruction_pointer(regs) - | |
494 | (thumb_mode(regs) ? 2 : 4); | |
495 | ||
496 | notify_die("Oops - bad syscall(2)", regs, &info, no, 0); | |
497 | return 0; | |
498 | } | |
499 | ||
500 | void __bad_xchg(volatile void *ptr, int size) | |
501 | { | |
502 | printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", | |
503 | __builtin_return_address(0), ptr, size); | |
504 | BUG(); | |
505 | } | |
506 | EXPORT_SYMBOL(__bad_xchg); | |
507 | ||
508 | /* | |
509 | * A data abort trap was taken, but we did not handle the instruction. | |
510 | * Try to abort the user program, or panic if it was the kernel. | |
511 | */ | |
512 | asmlinkage void | |
513 | baddataabort(int code, unsigned long instr, struct pt_regs *regs) | |
514 | { | |
515 | unsigned long addr = instruction_pointer(regs); | |
516 | siginfo_t info; | |
517 | ||
518 | #ifdef CONFIG_DEBUG_USER | |
519 | if (user_debug & UDBG_BADABORT) { | |
520 | printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", | |
521 | current->pid, current->comm, code, instr); | |
522 | dump_instr(regs); | |
523 | show_pte(current->mm, addr); | |
524 | } | |
525 | #endif | |
526 | ||
527 | info.si_signo = SIGILL; | |
528 | info.si_errno = 0; | |
529 | info.si_code = ILL_ILLOPC; | |
530 | info.si_addr = (void __user *)addr; | |
531 | ||
532 | notify_die("unknown data abort code", regs, &info, instr, 0); | |
533 | } | |
534 | ||
535 | volatile void __bug(const char *file, int line, void *data) | |
536 | { | |
537 | printk(KERN_CRIT"kernel BUG at %s:%d!", file, line); | |
538 | if (data) | |
539 | printk(" - extra data = %p", data); | |
540 | printk("\n"); | |
541 | *(int *)0 = 0; | |
542 | } | |
543 | EXPORT_SYMBOL(__bug); | |
544 | ||
545 | void __readwrite_bug(const char *fn) | |
546 | { | |
547 | printk("%s called, but not implemented\n", fn); | |
548 | BUG(); | |
549 | } | |
550 | EXPORT_SYMBOL(__readwrite_bug); | |
551 | ||
552 | void __pte_error(const char *file, int line, unsigned long val) | |
553 | { | |
554 | printk("%s:%d: bad pte %08lx.\n", file, line, val); | |
555 | } | |
556 | ||
557 | void __pmd_error(const char *file, int line, unsigned long val) | |
558 | { | |
559 | printk("%s:%d: bad pmd %08lx.\n", file, line, val); | |
560 | } | |
561 | ||
562 | void __pgd_error(const char *file, int line, unsigned long val) | |
563 | { | |
564 | printk("%s:%d: bad pgd %08lx.\n", file, line, val); | |
565 | } | |
566 | ||
567 | asmlinkage void __div0(void) | |
568 | { | |
569 | printk("Division by zero in kernel.\n"); | |
570 | dump_stack(); | |
571 | } | |
572 | EXPORT_SYMBOL(__div0); | |
573 | ||
574 | void abort(void) | |
575 | { | |
576 | BUG(); | |
577 | ||
578 | /* if that doesn't kill us, halt */ | |
579 | panic("Oops failed to kill thread"); | |
580 | } | |
581 | EXPORT_SYMBOL(abort); | |
582 | ||
583 | void __init trap_init(void) | |
584 | { | |
585 | extern void __trap_init(void); | |
586 | ||
587 | __trap_init(); | |
588 | flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE); | |
589 | modify_domain(DOMAIN_USER, DOMAIN_CLIENT); | |
590 | } |