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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/signal.h> | |
28 | #include <linux/sched/debug.h> | |
29 | #include <linux/sched/task_stack.h> | |
30 | #include <linux/irq.h> | |
31 | ||
32 | #include <linux/atomic.h> | |
33 | #include <asm/cacheflush.h> | |
34 | #include <asm/exception.h> | |
35 | #include <asm/unistd.h> | |
36 | #include <asm/traps.h> | |
37 | #include <asm/ptrace.h> | |
38 | #include <asm/unwind.h> | |
39 | #include <asm/tls.h> | |
40 | #include <asm/system_misc.h> | |
41 | #include <asm/opcodes.h> | |
42 | ||
43 | ||
44 | static const char *handler[]= { | |
45 | "prefetch abort", | |
46 | "data abort", | |
47 | "address exception", | |
48 | "interrupt", | |
49 | "undefined instruction", | |
50 | }; | |
51 | ||
52 | void *vectors_page; | |
53 | ||
54 | #ifdef CONFIG_DEBUG_USER | |
55 | unsigned int user_debug; | |
56 | ||
57 | static int __init user_debug_setup(char *str) | |
58 | { | |
59 | get_option(&str, &user_debug); | |
60 | return 1; | |
61 | } | |
62 | __setup("user_debug=", user_debug_setup); | |
63 | #endif | |
64 | ||
65 | static void dump_mem(const char *, const char *, unsigned long, unsigned long); | |
66 | ||
67 | void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) | |
68 | { | |
69 | #ifdef CONFIG_KALLSYMS | |
70 | printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); | |
71 | #else | |
72 | printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); | |
73 | #endif | |
74 | ||
75 | if (in_exception_text(where)) | |
76 | dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); | |
77 | } | |
78 | ||
79 | void dump_backtrace_stm(u32 *stack, u32 instruction) | |
80 | { | |
81 | char str[80], *p; | |
82 | unsigned int x; | |
83 | int reg; | |
84 | ||
85 | for (reg = 10, x = 0, p = str; reg >= 0; reg--) { | |
86 | if (instruction & BIT(reg)) { | |
87 | p += sprintf(p, " r%d:%08x", reg, *stack--); | |
88 | if (++x == 6) { | |
89 | x = 0; | |
90 | p = str; | |
91 | printk("%s\n", str); | |
92 | } | |
93 | } | |
94 | } | |
95 | if (p != str) | |
96 | printk("%s\n", str); | |
97 | } | |
98 | ||
99 | #ifndef CONFIG_ARM_UNWIND | |
100 | /* | |
101 | * Stack pointers should always be within the kernels view of | |
102 | * physical memory. If it is not there, then we can't dump | |
103 | * out any information relating to the stack. | |
104 | */ | |
105 | static int verify_stack(unsigned long sp) | |
106 | { | |
107 | if (sp < PAGE_OFFSET || | |
108 | (sp > (unsigned long)high_memory && high_memory != NULL)) | |
109 | return -EFAULT; | |
110 | ||
111 | return 0; | |
112 | } | |
113 | #endif | |
114 | ||
115 | /* | |
116 | * Dump out the contents of some memory nicely... | |
117 | */ | |
118 | static void dump_mem(const char *lvl, const char *str, unsigned long bottom, | |
119 | unsigned long top) | |
120 | { | |
121 | unsigned long first; | |
122 | mm_segment_t fs; | |
123 | int i; | |
124 | ||
125 | /* | |
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. | |
129 | */ | |
130 | fs = get_fs(); | |
131 | set_fs(KERNEL_DS); | |
132 | ||
133 | printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); | |
134 | ||
135 | for (first = bottom & ~31; first < top; first += 32) { | |
136 | unsigned long p; | |
137 | char str[sizeof(" 12345678") * 8 + 1]; | |
138 | ||
139 | memset(str, ' ', sizeof(str)); | |
140 | str[sizeof(str) - 1] = '\0'; | |
141 | ||
142 | for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { | |
143 | if (p >= bottom && p < top) { | |
144 | unsigned long val; | |
145 | if (__get_user(val, (unsigned long *)p) == 0) | |
146 | sprintf(str + i * 9, " %08lx", val); | |
147 | else | |
148 | sprintf(str + i * 9, " ????????"); | |
149 | } | |
150 | } | |
151 | printk("%s%04lx:%s\n", lvl, first & 0xffff, str); | |
152 | } | |
153 | ||
154 | set_fs(fs); | |
155 | } | |
156 | ||
157 | static void dump_instr(const char *lvl, struct pt_regs *regs) | |
158 | { | |
159 | unsigned long addr = instruction_pointer(regs); | |
160 | const int thumb = thumb_mode(regs); | |
161 | const int width = thumb ? 4 : 8; | |
162 | mm_segment_t fs; | |
163 | char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; | |
164 | int i; | |
165 | ||
166 | /* | |
167 | * We need to switch to kernel mode so that we can use __get_user | |
168 | * to safely read from kernel space. Note that we now dump the | |
169 | * code first, just in case the backtrace kills us. | |
170 | */ | |
171 | fs = get_fs(); | |
172 | set_fs(KERNEL_DS); | |
173 | ||
174 | for (i = -4; i < 1 + !!thumb; i++) { | |
175 | unsigned int val, bad; | |
176 | ||
177 | if (thumb) | |
178 | bad = __get_user(val, &((u16 *)addr)[i]); | |
179 | else | |
180 | bad = __get_user(val, &((u32 *)addr)[i]); | |
181 | ||
182 | if (!bad) | |
183 | p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", | |
184 | width, val); | |
185 | else { | |
186 | p += sprintf(p, "bad PC value"); | |
187 | break; | |
188 | } | |
189 | } | |
190 | printk("%sCode: %s\n", lvl, str); | |
191 | ||
192 | set_fs(fs); | |
193 | } | |
194 | ||
195 | #ifdef CONFIG_ARM_UNWIND | |
196 | static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | |
197 | { | |
198 | unwind_backtrace(regs, tsk); | |
199 | } | |
200 | #else | |
201 | static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | |
202 | { | |
203 | unsigned int fp, mode; | |
204 | int ok = 1; | |
205 | ||
206 | printk("Backtrace: "); | |
207 | ||
208 | if (!tsk) | |
209 | tsk = current; | |
210 | ||
211 | if (regs) { | |
212 | fp = frame_pointer(regs); | |
213 | mode = processor_mode(regs); | |
214 | } else if (tsk != current) { | |
215 | fp = thread_saved_fp(tsk); | |
216 | mode = 0x10; | |
217 | } else { | |
218 | asm("mov %0, fp" : "=r" (fp) : : "cc"); | |
219 | mode = 0x10; | |
220 | } | |
221 | ||
222 | if (!fp) { | |
223 | pr_cont("no frame pointer"); | |
224 | ok = 0; | |
225 | } else if (verify_stack(fp)) { | |
226 | pr_cont("invalid frame pointer 0x%08x", fp); | |
227 | ok = 0; | |
228 | } else if (fp < (unsigned long)end_of_stack(tsk)) | |
229 | pr_cont("frame pointer underflow"); | |
230 | pr_cont("\n"); | |
231 | ||
232 | if (ok) | |
233 | c_backtrace(fp, mode); | |
234 | } | |
235 | #endif | |
236 | ||
237 | void show_stack(struct task_struct *tsk, unsigned long *sp) | |
238 | { | |
239 | dump_backtrace(NULL, tsk); | |
240 | barrier(); | |
241 | } | |
242 | ||
243 | #ifdef CONFIG_PREEMPT | |
244 | #define S_PREEMPT " PREEMPT" | |
245 | #else | |
246 | #define S_PREEMPT "" | |
247 | #endif | |
248 | #ifdef CONFIG_SMP | |
249 | #define S_SMP " SMP" | |
250 | #else | |
251 | #define S_SMP "" | |
252 | #endif | |
253 | #ifdef CONFIG_THUMB2_KERNEL | |
254 | #define S_ISA " THUMB2" | |
255 | #else | |
256 | #define S_ISA " ARM" | |
257 | #endif | |
258 | ||
259 | static int __die(const char *str, int err, struct pt_regs *regs) | |
260 | { | |
261 | struct task_struct *tsk = current; | |
262 | static int die_counter; | |
263 | int ret; | |
264 | ||
265 | pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", | |
266 | str, err, ++die_counter); | |
267 | ||
268 | /* trap and error numbers are mostly meaningless on ARM */ | |
269 | ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); | |
270 | if (ret == NOTIFY_STOP) | |
271 | return 1; | |
272 | ||
273 | print_modules(); | |
274 | __show_regs(regs); | |
275 | pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", | |
276 | TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); | |
277 | ||
278 | if (!user_mode(regs) || in_interrupt()) { | |
279 | dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, | |
280 | THREAD_SIZE + (unsigned long)task_stack_page(tsk)); | |
281 | dump_backtrace(regs, tsk); | |
282 | dump_instr(KERN_EMERG, regs); | |
283 | } | |
284 | ||
285 | return 0; | |
286 | } | |
287 | ||
288 | static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; | |
289 | static int die_owner = -1; | |
290 | static unsigned int die_nest_count; | |
291 | ||
292 | static unsigned long oops_begin(void) | |
293 | { | |
294 | int cpu; | |
295 | unsigned long flags; | |
296 | ||
297 | oops_enter(); | |
298 | ||
299 | /* racy, but better than risking deadlock. */ | |
300 | raw_local_irq_save(flags); | |
301 | cpu = smp_processor_id(); | |
302 | if (!arch_spin_trylock(&die_lock)) { | |
303 | if (cpu == die_owner) | |
304 | /* nested oops. should stop eventually */; | |
305 | else | |
306 | arch_spin_lock(&die_lock); | |
307 | } | |
308 | die_nest_count++; | |
309 | die_owner = cpu; | |
310 | console_verbose(); | |
311 | bust_spinlocks(1); | |
312 | return flags; | |
313 | } | |
314 | ||
315 | static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) | |
316 | { | |
317 | if (regs && kexec_should_crash(current)) | |
318 | crash_kexec(regs); | |
319 | ||
320 | bust_spinlocks(0); | |
321 | die_owner = -1; | |
322 | add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); | |
323 | die_nest_count--; | |
324 | if (!die_nest_count) | |
325 | /* Nest count reaches zero, release the lock. */ | |
326 | arch_spin_unlock(&die_lock); | |
327 | raw_local_irq_restore(flags); | |
328 | oops_exit(); | |
329 | ||
330 | if (in_interrupt()) | |
331 | panic("Fatal exception in interrupt"); | |
332 | if (panic_on_oops) | |
333 | panic("Fatal exception"); | |
334 | if (signr) | |
335 | do_exit(signr); | |
336 | } | |
337 | ||
338 | /* | |
339 | * This function is protected against re-entrancy. | |
340 | */ | |
341 | void die(const char *str, struct pt_regs *regs, int err) | |
342 | { | |
343 | enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; | |
344 | unsigned long flags = oops_begin(); | |
345 | int sig = SIGSEGV; | |
346 | ||
347 | if (!user_mode(regs)) | |
348 | bug_type = report_bug(regs->ARM_pc, regs); | |
349 | if (bug_type != BUG_TRAP_TYPE_NONE) | |
350 | str = "Oops - BUG"; | |
351 | ||
352 | if (__die(str, err, regs)) | |
353 | sig = 0; | |
354 | ||
355 | oops_end(flags, regs, sig); | |
356 | } | |
357 | ||
358 | void arm_notify_die(const char *str, struct pt_regs *regs, | |
359 | struct siginfo *info, unsigned long err, unsigned long trap) | |
360 | { | |
361 | if (user_mode(regs)) { | |
362 | current->thread.error_code = err; | |
363 | current->thread.trap_no = trap; | |
364 | ||
365 | force_sig_info(info->si_signo, info, current); | |
366 | } else { | |
367 | die(str, regs, err); | |
368 | } | |
369 | } | |
370 | ||
371 | #ifdef CONFIG_GENERIC_BUG | |
372 | ||
373 | int is_valid_bugaddr(unsigned long pc) | |
374 | { | |
375 | #ifdef CONFIG_THUMB2_KERNEL | |
376 | u16 bkpt; | |
377 | u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); | |
378 | #else | |
379 | u32 bkpt; | |
380 | u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); | |
381 | #endif | |
382 | ||
383 | if (probe_kernel_address((unsigned *)pc, bkpt)) | |
384 | return 0; | |
385 | ||
386 | return bkpt == insn; | |
387 | } | |
388 | ||
389 | #endif | |
390 | ||
391 | static LIST_HEAD(undef_hook); | |
392 | static DEFINE_RAW_SPINLOCK(undef_lock); | |
393 | ||
394 | void register_undef_hook(struct undef_hook *hook) | |
395 | { | |
396 | unsigned long flags; | |
397 | ||
398 | raw_spin_lock_irqsave(&undef_lock, flags); | |
399 | list_add(&hook->node, &undef_hook); | |
400 | raw_spin_unlock_irqrestore(&undef_lock, flags); | |
401 | } | |
402 | ||
403 | void unregister_undef_hook(struct undef_hook *hook) | |
404 | { | |
405 | unsigned long flags; | |
406 | ||
407 | raw_spin_lock_irqsave(&undef_lock, flags); | |
408 | list_del(&hook->node); | |
409 | raw_spin_unlock_irqrestore(&undef_lock, flags); | |
410 | } | |
411 | ||
412 | static int call_undef_hook(struct pt_regs *regs, unsigned int instr) | |
413 | { | |
414 | struct undef_hook *hook; | |
415 | unsigned long flags; | |
416 | int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; | |
417 | ||
418 | raw_spin_lock_irqsave(&undef_lock, flags); | |
419 | list_for_each_entry(hook, &undef_hook, node) | |
420 | if ((instr & hook->instr_mask) == hook->instr_val && | |
421 | (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) | |
422 | fn = hook->fn; | |
423 | raw_spin_unlock_irqrestore(&undef_lock, flags); | |
424 | ||
425 | return fn ? fn(regs, instr) : 1; | |
426 | } | |
427 | ||
428 | asmlinkage void __exception do_undefinstr(struct pt_regs *regs) | |
429 | { | |
430 | unsigned int instr; | |
431 | siginfo_t info; | |
432 | void __user *pc; | |
433 | ||
434 | pc = (void __user *)instruction_pointer(regs); | |
435 | ||
436 | if (processor_mode(regs) == SVC_MODE) { | |
437 | #ifdef CONFIG_THUMB2_KERNEL | |
438 | if (thumb_mode(regs)) { | |
439 | instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); | |
440 | if (is_wide_instruction(instr)) { | |
441 | u16 inst2; | |
442 | inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); | |
443 | instr = __opcode_thumb32_compose(instr, inst2); | |
444 | } | |
445 | } else | |
446 | #endif | |
447 | instr = __mem_to_opcode_arm(*(u32 *) pc); | |
448 | } else if (thumb_mode(regs)) { | |
449 | if (get_user(instr, (u16 __user *)pc)) | |
450 | goto die_sig; | |
451 | instr = __mem_to_opcode_thumb16(instr); | |
452 | if (is_wide_instruction(instr)) { | |
453 | unsigned int instr2; | |
454 | if (get_user(instr2, (u16 __user *)pc+1)) | |
455 | goto die_sig; | |
456 | instr2 = __mem_to_opcode_thumb16(instr2); | |
457 | instr = __opcode_thumb32_compose(instr, instr2); | |
458 | } | |
459 | } else { | |
460 | if (get_user(instr, (u32 __user *)pc)) | |
461 | goto die_sig; | |
462 | instr = __mem_to_opcode_arm(instr); | |
463 | } | |
464 | ||
465 | if (call_undef_hook(regs, instr) == 0) | |
466 | return; | |
467 | ||
468 | die_sig: | |
469 | #ifdef CONFIG_DEBUG_USER | |
470 | if (user_debug & UDBG_UNDEFINED) { | |
471 | pr_info("%s (%d): undefined instruction: pc=%p\n", | |
472 | current->comm, task_pid_nr(current), pc); | |
473 | __show_regs(regs); | |
474 | dump_instr(KERN_INFO, regs); | |
475 | } | |
476 | #endif | |
477 | ||
478 | info.si_signo = SIGILL; | |
479 | info.si_errno = 0; | |
480 | info.si_code = ILL_ILLOPC; | |
481 | info.si_addr = pc; | |
482 | ||
483 | arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); | |
484 | } | |
485 | ||
486 | /* | |
487 | * Handle FIQ similarly to NMI on x86 systems. | |
488 | * | |
489 | * The runtime environment for NMIs is extremely restrictive | |
490 | * (NMIs can pre-empt critical sections meaning almost all locking is | |
491 | * forbidden) meaning this default FIQ handling must only be used in | |
492 | * circumstances where non-maskability improves robustness, such as | |
493 | * watchdog or debug logic. | |
494 | * | |
495 | * This handler is not appropriate for general purpose use in drivers | |
496 | * platform code and can be overrideen using set_fiq_handler. | |
497 | */ | |
498 | asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) | |
499 | { | |
500 | struct pt_regs *old_regs = set_irq_regs(regs); | |
501 | ||
502 | nmi_enter(); | |
503 | ||
504 | /* nop. FIQ handlers for special arch/arm features can be added here. */ | |
505 | ||
506 | nmi_exit(); | |
507 | ||
508 | set_irq_regs(old_regs); | |
509 | } | |
510 | ||
511 | /* | |
512 | * bad_mode handles the impossible case in the vectors. If you see one of | |
513 | * these, then it's extremely serious, and could mean you have buggy hardware. | |
514 | * It never returns, and never tries to sync. We hope that we can at least | |
515 | * dump out some state information... | |
516 | */ | |
517 | asmlinkage void bad_mode(struct pt_regs *regs, int reason) | |
518 | { | |
519 | console_verbose(); | |
520 | ||
521 | pr_crit("Bad mode in %s handler detected\n", handler[reason]); | |
522 | ||
523 | die("Oops - bad mode", regs, 0); | |
524 | local_irq_disable(); | |
525 | panic("bad mode"); | |
526 | } | |
527 | ||
528 | static int bad_syscall(int n, struct pt_regs *regs) | |
529 | { | |
530 | siginfo_t info; | |
531 | ||
532 | if ((current->personality & PER_MASK) != PER_LINUX) { | |
533 | send_sig(SIGSEGV, current, 1); | |
534 | return regs->ARM_r0; | |
535 | } | |
536 | ||
537 | #ifdef CONFIG_DEBUG_USER | |
538 | if (user_debug & UDBG_SYSCALL) { | |
539 | pr_err("[%d] %s: obsolete system call %08x.\n", | |
540 | task_pid_nr(current), current->comm, n); | |
541 | dump_instr(KERN_ERR, regs); | |
542 | } | |
543 | #endif | |
544 | ||
545 | info.si_signo = SIGILL; | |
546 | info.si_errno = 0; | |
547 | info.si_code = ILL_ILLTRP; | |
548 | info.si_addr = (void __user *)instruction_pointer(regs) - | |
549 | (thumb_mode(regs) ? 2 : 4); | |
550 | ||
551 | arm_notify_die("Oops - bad syscall", regs, &info, n, 0); | |
552 | ||
553 | return regs->ARM_r0; | |
554 | } | |
555 | ||
556 | static inline int | |
557 | __do_cache_op(unsigned long start, unsigned long end) | |
558 | { | |
559 | int ret; | |
560 | ||
561 | do { | |
562 | unsigned long chunk = min(PAGE_SIZE, end - start); | |
563 | ||
564 | if (fatal_signal_pending(current)) | |
565 | return 0; | |
566 | ||
567 | ret = flush_cache_user_range(start, start + chunk); | |
568 | if (ret) | |
569 | return ret; | |
570 | ||
571 | cond_resched(); | |
572 | start += chunk; | |
573 | } while (start < end); | |
574 | ||
575 | return 0; | |
576 | } | |
577 | ||
578 | static inline int | |
579 | do_cache_op(unsigned long start, unsigned long end, int flags) | |
580 | { | |
581 | if (end < start || flags) | |
582 | return -EINVAL; | |
583 | ||
584 | if (!access_ok(VERIFY_READ, start, end - start)) | |
585 | return -EFAULT; | |
586 | ||
587 | return __do_cache_op(start, end); | |
588 | } | |
589 | ||
590 | /* | |
591 | * Handle all unrecognised system calls. | |
592 | * 0x9f0000 - 0x9fffff are some more esoteric system calls | |
593 | */ | |
594 | #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) | |
595 | asmlinkage int arm_syscall(int no, struct pt_regs *regs) | |
596 | { | |
597 | siginfo_t info; | |
598 | ||
599 | if ((no >> 16) != (__ARM_NR_BASE>> 16)) | |
600 | return bad_syscall(no, regs); | |
601 | ||
602 | switch (no & 0xffff) { | |
603 | case 0: /* branch through 0 */ | |
604 | info.si_signo = SIGSEGV; | |
605 | info.si_errno = 0; | |
606 | info.si_code = SEGV_MAPERR; | |
607 | info.si_addr = NULL; | |
608 | ||
609 | arm_notify_die("branch through zero", regs, &info, 0, 0); | |
610 | return 0; | |
611 | ||
612 | case NR(breakpoint): /* SWI BREAK_POINT */ | |
613 | regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; | |
614 | ptrace_break(current, regs); | |
615 | return regs->ARM_r0; | |
616 | ||
617 | /* | |
618 | * Flush a region from virtual address 'r0' to virtual address 'r1' | |
619 | * _exclusive_. There is no alignment requirement on either address; | |
620 | * user space does not need to know the hardware cache layout. | |
621 | * | |
622 | * r2 contains flags. It should ALWAYS be passed as ZERO until it | |
623 | * is defined to be something else. For now we ignore it, but may | |
624 | * the fires of hell burn in your belly if you break this rule. ;) | |
625 | * | |
626 | * (at a later date, we may want to allow this call to not flush | |
627 | * various aspects of the cache. Passing '0' will guarantee that | |
628 | * everything necessary gets flushed to maintain consistency in | |
629 | * the specified region). | |
630 | */ | |
631 | case NR(cacheflush): | |
632 | return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); | |
633 | ||
634 | case NR(usr26): | |
635 | if (!(elf_hwcap & HWCAP_26BIT)) | |
636 | break; | |
637 | regs->ARM_cpsr &= ~MODE32_BIT; | |
638 | return regs->ARM_r0; | |
639 | ||
640 | case NR(usr32): | |
641 | if (!(elf_hwcap & HWCAP_26BIT)) | |
642 | break; | |
643 | regs->ARM_cpsr |= MODE32_BIT; | |
644 | return regs->ARM_r0; | |
645 | ||
646 | case NR(set_tls): | |
647 | set_tls(regs->ARM_r0); | |
648 | return 0; | |
649 | ||
650 | default: | |
651 | /* Calls 9f00xx..9f07ff are defined to return -ENOSYS | |
652 | if not implemented, rather than raising SIGILL. This | |
653 | way the calling program can gracefully determine whether | |
654 | a feature is supported. */ | |
655 | if ((no & 0xffff) <= 0x7ff) | |
656 | return -ENOSYS; | |
657 | break; | |
658 | } | |
659 | #ifdef CONFIG_DEBUG_USER | |
660 | /* | |
661 | * experience shows that these seem to indicate that | |
662 | * something catastrophic has happened | |
663 | */ | |
664 | if (user_debug & UDBG_SYSCALL) { | |
665 | pr_err("[%d] %s: arm syscall %d\n", | |
666 | task_pid_nr(current), current->comm, no); | |
667 | dump_instr("", regs); | |
668 | if (user_mode(regs)) { | |
669 | __show_regs(regs); | |
670 | c_backtrace(frame_pointer(regs), processor_mode(regs)); | |
671 | } | |
672 | } | |
673 | #endif | |
674 | info.si_signo = SIGILL; | |
675 | info.si_errno = 0; | |
676 | info.si_code = ILL_ILLTRP; | |
677 | info.si_addr = (void __user *)instruction_pointer(regs) - | |
678 | (thumb_mode(regs) ? 2 : 4); | |
679 | ||
680 | arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); | |
681 | return 0; | |
682 | } | |
683 | ||
684 | #ifdef CONFIG_TLS_REG_EMUL | |
685 | ||
686 | /* | |
687 | * We might be running on an ARMv6+ processor which should have the TLS | |
688 | * register but for some reason we can't use it, or maybe an SMP system | |
689 | * using a pre-ARMv6 processor (there are apparently a few prototypes like | |
690 | * that in existence) and therefore access to that register must be | |
691 | * emulated. | |
692 | */ | |
693 | ||
694 | static int get_tp_trap(struct pt_regs *regs, unsigned int instr) | |
695 | { | |
696 | int reg = (instr >> 12) & 15; | |
697 | if (reg == 15) | |
698 | return 1; | |
699 | regs->uregs[reg] = current_thread_info()->tp_value[0]; | |
700 | regs->ARM_pc += 4; | |
701 | return 0; | |
702 | } | |
703 | ||
704 | static struct undef_hook arm_mrc_hook = { | |
705 | .instr_mask = 0x0fff0fff, | |
706 | .instr_val = 0x0e1d0f70, | |
707 | .cpsr_mask = PSR_T_BIT, | |
708 | .cpsr_val = 0, | |
709 | .fn = get_tp_trap, | |
710 | }; | |
711 | ||
712 | static int __init arm_mrc_hook_init(void) | |
713 | { | |
714 | register_undef_hook(&arm_mrc_hook); | |
715 | return 0; | |
716 | } | |
717 | ||
718 | late_initcall(arm_mrc_hook_init); | |
719 | ||
720 | #endif | |
721 | ||
722 | /* | |
723 | * A data abort trap was taken, but we did not handle the instruction. | |
724 | * Try to abort the user program, or panic if it was the kernel. | |
725 | */ | |
726 | asmlinkage void | |
727 | baddataabort(int code, unsigned long instr, struct pt_regs *regs) | |
728 | { | |
729 | unsigned long addr = instruction_pointer(regs); | |
730 | siginfo_t info; | |
731 | ||
732 | #ifdef CONFIG_DEBUG_USER | |
733 | if (user_debug & UDBG_BADABORT) { | |
734 | pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", | |
735 | task_pid_nr(current), current->comm, code, instr); | |
736 | dump_instr(KERN_ERR, regs); | |
737 | show_pte(current->mm, addr); | |
738 | } | |
739 | #endif | |
740 | ||
741 | info.si_signo = SIGILL; | |
742 | info.si_errno = 0; | |
743 | info.si_code = ILL_ILLOPC; | |
744 | info.si_addr = (void __user *)addr; | |
745 | ||
746 | arm_notify_die("unknown data abort code", regs, &info, instr, 0); | |
747 | } | |
748 | ||
749 | void __readwrite_bug(const char *fn) | |
750 | { | |
751 | pr_err("%s called, but not implemented\n", fn); | |
752 | BUG(); | |
753 | } | |
754 | EXPORT_SYMBOL(__readwrite_bug); | |
755 | ||
756 | void __pte_error(const char *file, int line, pte_t pte) | |
757 | { | |
758 | pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); | |
759 | } | |
760 | ||
761 | void __pmd_error(const char *file, int line, pmd_t pmd) | |
762 | { | |
763 | pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); | |
764 | } | |
765 | ||
766 | void __pgd_error(const char *file, int line, pgd_t pgd) | |
767 | { | |
768 | pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); | |
769 | } | |
770 | ||
771 | asmlinkage void __div0(void) | |
772 | { | |
773 | pr_err("Division by zero in kernel.\n"); | |
774 | dump_stack(); | |
775 | } | |
776 | EXPORT_SYMBOL(__div0); | |
777 | ||
778 | void abort(void) | |
779 | { | |
780 | BUG(); | |
781 | ||
782 | /* if that doesn't kill us, halt */ | |
783 | panic("Oops failed to kill thread"); | |
784 | } | |
785 | EXPORT_SYMBOL(abort); | |
786 | ||
787 | void __init trap_init(void) | |
788 | { | |
789 | return; | |
790 | } | |
791 | ||
792 | #ifdef CONFIG_KUSER_HELPERS | |
793 | static void __init kuser_init(void *vectors) | |
794 | { | |
795 | extern char __kuser_helper_start[], __kuser_helper_end[]; | |
796 | int kuser_sz = __kuser_helper_end - __kuser_helper_start; | |
797 | ||
798 | memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); | |
799 | ||
800 | /* | |
801 | * vectors + 0xfe0 = __kuser_get_tls | |
802 | * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 | |
803 | */ | |
804 | if (tls_emu || has_tls_reg) | |
805 | memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); | |
806 | } | |
807 | #else | |
808 | static inline void __init kuser_init(void *vectors) | |
809 | { | |
810 | } | |
811 | #endif | |
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 | unsigned i; | |
820 | ||
821 | vectors_page = vectors_base; | |
822 | ||
823 | /* | |
824 | * Poison the vectors page with an undefined instruction. This | |
825 | * instruction is chosen to be undefined for both ARM and Thumb | |
826 | * ISAs. The Thumb version is an undefined instruction with a | |
827 | * branch back to the undefined instruction. | |
828 | */ | |
829 | for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) | |
830 | ((u32 *)vectors_base)[i] = 0xe7fddef1; | |
831 | ||
832 | /* | |
833 | * Copy the vectors, stubs and kuser helpers (in entry-armv.S) | |
834 | * into the vector page, mapped at 0xffff0000, and ensure these | |
835 | * are visible to the instruction stream. | |
836 | */ | |
837 | memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); | |
838 | memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); | |
839 | ||
840 | kuser_init(vectors_base); | |
841 | ||
842 | flush_icache_range(vectors, vectors + PAGE_SIZE * 2); | |
843 | #else /* ifndef CONFIG_CPU_V7M */ | |
844 | /* | |
845 | * on V7-M there is no need to copy the vector table to a dedicated | |
846 | * memory area. The address is configurable and so a table in the kernel | |
847 | * image can be used. | |
848 | */ | |
849 | #endif | |
850 | } |