xref: /openbmc/linux/arch/arm/mm/fault.c (revision 9c1f8594)
1 /*
2  *  linux/arch/arm/mm/fault.c
3  *
4  *  Copyright (C) 1995  Linus Torvalds
5  *  Modifications for ARM processor (c) 1995-2004 Russell King
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 #include <linux/module.h>
12 #include <linux/signal.h>
13 #include <linux/mm.h>
14 #include <linux/hardirq.h>
15 #include <linux/init.h>
16 #include <linux/kprobes.h>
17 #include <linux/uaccess.h>
18 #include <linux/page-flags.h>
19 #include <linux/sched.h>
20 #include <linux/highmem.h>
21 #include <linux/perf_event.h>
22 
23 #include <asm/system.h>
24 #include <asm/pgtable.h>
25 #include <asm/tlbflush.h>
26 
27 #include "fault.h"
28 
29 /*
30  * Fault status register encodings.  We steal bit 31 for our own purposes.
31  */
32 #define FSR_LNX_PF		(1 << 31)
33 #define FSR_WRITE		(1 << 11)
34 #define FSR_FS4			(1 << 10)
35 #define FSR_FS3_0		(15)
36 
37 static inline int fsr_fs(unsigned int fsr)
38 {
39 	return (fsr & FSR_FS3_0) | (fsr & FSR_FS4) >> 6;
40 }
41 
42 #ifdef CONFIG_MMU
43 
44 #ifdef CONFIG_KPROBES
45 static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
46 {
47 	int ret = 0;
48 
49 	if (!user_mode(regs)) {
50 		/* kprobe_running() needs smp_processor_id() */
51 		preempt_disable();
52 		if (kprobe_running() && kprobe_fault_handler(regs, fsr))
53 			ret = 1;
54 		preempt_enable();
55 	}
56 
57 	return ret;
58 }
59 #else
60 static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
61 {
62 	return 0;
63 }
64 #endif
65 
66 /*
67  * This is useful to dump out the page tables associated with
68  * 'addr' in mm 'mm'.
69  */
70 void show_pte(struct mm_struct *mm, unsigned long addr)
71 {
72 	pgd_t *pgd;
73 
74 	if (!mm)
75 		mm = &init_mm;
76 
77 	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
78 	pgd = pgd_offset(mm, addr);
79 	printk(KERN_ALERT "[%08lx] *pgd=%08llx",
80 			addr, (long long)pgd_val(*pgd));
81 
82 	do {
83 		pud_t *pud;
84 		pmd_t *pmd;
85 		pte_t *pte;
86 
87 		if (pgd_none(*pgd))
88 			break;
89 
90 		if (pgd_bad(*pgd)) {
91 			printk("(bad)");
92 			break;
93 		}
94 
95 		pud = pud_offset(pgd, addr);
96 		if (PTRS_PER_PUD != 1)
97 			printk(", *pud=%08llx", (long long)pud_val(*pud));
98 
99 		if (pud_none(*pud))
100 			break;
101 
102 		if (pud_bad(*pud)) {
103 			printk("(bad)");
104 			break;
105 		}
106 
107 		pmd = pmd_offset(pud, addr);
108 		if (PTRS_PER_PMD != 1)
109 			printk(", *pmd=%08llx", (long long)pmd_val(*pmd));
110 
111 		if (pmd_none(*pmd))
112 			break;
113 
114 		if (pmd_bad(*pmd)) {
115 			printk("(bad)");
116 			break;
117 		}
118 
119 		/* We must not map this if we have highmem enabled */
120 		if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
121 			break;
122 
123 		pte = pte_offset_map(pmd, addr);
124 		printk(", *pte=%08llx", (long long)pte_val(*pte));
125 		printk(", *ppte=%08llx",
126 		       (long long)pte_val(pte[PTE_HWTABLE_PTRS]));
127 		pte_unmap(pte);
128 	} while(0);
129 
130 	printk("\n");
131 }
132 #else					/* CONFIG_MMU */
133 void show_pte(struct mm_struct *mm, unsigned long addr)
134 { }
135 #endif					/* CONFIG_MMU */
136 
137 /*
138  * Oops.  The kernel tried to access some page that wasn't present.
139  */
140 static void
141 __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
142 		  struct pt_regs *regs)
143 {
144 	/*
145 	 * Are we prepared to handle this kernel fault?
146 	 */
147 	if (fixup_exception(regs))
148 		return;
149 
150 	/*
151 	 * No handler, we'll have to terminate things with extreme prejudice.
152 	 */
153 	bust_spinlocks(1);
154 	printk(KERN_ALERT
155 		"Unable to handle kernel %s at virtual address %08lx\n",
156 		(addr < PAGE_SIZE) ? "NULL pointer dereference" :
157 		"paging request", addr);
158 
159 	show_pte(mm, addr);
160 	die("Oops", regs, fsr);
161 	bust_spinlocks(0);
162 	do_exit(SIGKILL);
163 }
164 
165 /*
166  * Something tried to access memory that isn't in our memory map..
167  * User mode accesses just cause a SIGSEGV
168  */
169 static void
170 __do_user_fault(struct task_struct *tsk, unsigned long addr,
171 		unsigned int fsr, unsigned int sig, int code,
172 		struct pt_regs *regs)
173 {
174 	struct siginfo si;
175 
176 #ifdef CONFIG_DEBUG_USER
177 	if (user_debug & UDBG_SEGV) {
178 		printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
179 		       tsk->comm, sig, addr, fsr);
180 		show_pte(tsk->mm, addr);
181 		show_regs(regs);
182 	}
183 #endif
184 
185 	tsk->thread.address = addr;
186 	tsk->thread.error_code = fsr;
187 	tsk->thread.trap_no = 14;
188 	si.si_signo = sig;
189 	si.si_errno = 0;
190 	si.si_code = code;
191 	si.si_addr = (void __user *)addr;
192 	force_sig_info(sig, &si, tsk);
193 }
194 
195 void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
196 {
197 	struct task_struct *tsk = current;
198 	struct mm_struct *mm = tsk->active_mm;
199 
200 	/*
201 	 * If we are in kernel mode at this point, we
202 	 * have no context to handle this fault with.
203 	 */
204 	if (user_mode(regs))
205 		__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
206 	else
207 		__do_kernel_fault(mm, addr, fsr, regs);
208 }
209 
210 #ifdef CONFIG_MMU
211 #define VM_FAULT_BADMAP		0x010000
212 #define VM_FAULT_BADACCESS	0x020000
213 
214 /*
215  * Check that the permissions on the VMA allow for the fault which occurred.
216  * If we encountered a write fault, we must have write permission, otherwise
217  * we allow any permission.
218  */
219 static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
220 {
221 	unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
222 
223 	if (fsr & FSR_WRITE)
224 		mask = VM_WRITE;
225 	if (fsr & FSR_LNX_PF)
226 		mask = VM_EXEC;
227 
228 	return vma->vm_flags & mask ? false : true;
229 }
230 
231 static int __kprobes
232 __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
233 		struct task_struct *tsk)
234 {
235 	struct vm_area_struct *vma;
236 	int fault;
237 
238 	vma = find_vma(mm, addr);
239 	fault = VM_FAULT_BADMAP;
240 	if (unlikely(!vma))
241 		goto out;
242 	if (unlikely(vma->vm_start > addr))
243 		goto check_stack;
244 
245 	/*
246 	 * Ok, we have a good vm_area for this
247 	 * memory access, so we can handle it.
248 	 */
249 good_area:
250 	if (access_error(fsr, vma)) {
251 		fault = VM_FAULT_BADACCESS;
252 		goto out;
253 	}
254 
255 	/*
256 	 * If for any reason at all we couldn't handle the fault, make
257 	 * sure we exit gracefully rather than endlessly redo the fault.
258 	 */
259 	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
260 	if (unlikely(fault & VM_FAULT_ERROR))
261 		return fault;
262 	if (fault & VM_FAULT_MAJOR)
263 		tsk->maj_flt++;
264 	else
265 		tsk->min_flt++;
266 	return fault;
267 
268 check_stack:
269 	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
270 		goto good_area;
271 out:
272 	return fault;
273 }
274 
275 static int __kprobes
276 do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
277 {
278 	struct task_struct *tsk;
279 	struct mm_struct *mm;
280 	int fault, sig, code;
281 
282 	if (notify_page_fault(regs, fsr))
283 		return 0;
284 
285 	tsk = current;
286 	mm  = tsk->mm;
287 
288 	/* Enable interrupts if they were enabled in the parent context. */
289 	if (interrupts_enabled(regs))
290 		local_irq_enable();
291 
292 	/*
293 	 * If we're in an interrupt or have no user
294 	 * context, we must not take the fault..
295 	 */
296 	if (in_atomic() || !mm)
297 		goto no_context;
298 
299 	/*
300 	 * As per x86, we may deadlock here.  However, since the kernel only
301 	 * validly references user space from well defined areas of the code,
302 	 * we can bug out early if this is from code which shouldn't.
303 	 */
304 	if (!down_read_trylock(&mm->mmap_sem)) {
305 		if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
306 			goto no_context;
307 		down_read(&mm->mmap_sem);
308 	} else {
309 		/*
310 		 * The above down_read_trylock() might have succeeded in
311 		 * which case, we'll have missed the might_sleep() from
312 		 * down_read()
313 		 */
314 		might_sleep();
315 #ifdef CONFIG_DEBUG_VM
316 		if (!user_mode(regs) &&
317 		    !search_exception_tables(regs->ARM_pc))
318 			goto no_context;
319 #endif
320 	}
321 
322 	fault = __do_page_fault(mm, addr, fsr, tsk);
323 	up_read(&mm->mmap_sem);
324 
325 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
326 	if (fault & VM_FAULT_MAJOR)
327 		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, addr);
328 	else if (fault & VM_FAULT_MINOR)
329 		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, addr);
330 
331 	/*
332 	 * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
333 	 */
334 	if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
335 		return 0;
336 
337 	if (fault & VM_FAULT_OOM) {
338 		/*
339 		 * We ran out of memory, call the OOM killer, and return to
340 		 * userspace (which will retry the fault, or kill us if we
341 		 * got oom-killed)
342 		 */
343 		pagefault_out_of_memory();
344 		return 0;
345 	}
346 
347 	/*
348 	 * If we are in kernel mode at this point, we
349 	 * have no context to handle this fault with.
350 	 */
351 	if (!user_mode(regs))
352 		goto no_context;
353 
354 	if (fault & VM_FAULT_SIGBUS) {
355 		/*
356 		 * We had some memory, but were unable to
357 		 * successfully fix up this page fault.
358 		 */
359 		sig = SIGBUS;
360 		code = BUS_ADRERR;
361 	} else {
362 		/*
363 		 * Something tried to access memory that
364 		 * isn't in our memory map..
365 		 */
366 		sig = SIGSEGV;
367 		code = fault == VM_FAULT_BADACCESS ?
368 			SEGV_ACCERR : SEGV_MAPERR;
369 	}
370 
371 	__do_user_fault(tsk, addr, fsr, sig, code, regs);
372 	return 0;
373 
374 no_context:
375 	__do_kernel_fault(mm, addr, fsr, regs);
376 	return 0;
377 }
378 #else					/* CONFIG_MMU */
379 static int
380 do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
381 {
382 	return 0;
383 }
384 #endif					/* CONFIG_MMU */
385 
386 /*
387  * First Level Translation Fault Handler
388  *
389  * We enter here because the first level page table doesn't contain
390  * a valid entry for the address.
391  *
392  * If the address is in kernel space (>= TASK_SIZE), then we are
393  * probably faulting in the vmalloc() area.
394  *
395  * If the init_task's first level page tables contains the relevant
396  * entry, we copy the it to this task.  If not, we send the process
397  * a signal, fixup the exception, or oops the kernel.
398  *
399  * NOTE! We MUST NOT take any locks for this case. We may be in an
400  * interrupt or a critical region, and should only copy the information
401  * from the master page table, nothing more.
402  */
403 #ifdef CONFIG_MMU
404 static int __kprobes
405 do_translation_fault(unsigned long addr, unsigned int fsr,
406 		     struct pt_regs *regs)
407 {
408 	unsigned int index;
409 	pgd_t *pgd, *pgd_k;
410 	pud_t *pud, *pud_k;
411 	pmd_t *pmd, *pmd_k;
412 
413 	if (addr < TASK_SIZE)
414 		return do_page_fault(addr, fsr, regs);
415 
416 	if (user_mode(regs))
417 		goto bad_area;
418 
419 	index = pgd_index(addr);
420 
421 	/*
422 	 * FIXME: CP15 C1 is write only on ARMv3 architectures.
423 	 */
424 	pgd = cpu_get_pgd() + index;
425 	pgd_k = init_mm.pgd + index;
426 
427 	if (pgd_none(*pgd_k))
428 		goto bad_area;
429 	if (!pgd_present(*pgd))
430 		set_pgd(pgd, *pgd_k);
431 
432 	pud = pud_offset(pgd, addr);
433 	pud_k = pud_offset(pgd_k, addr);
434 
435 	if (pud_none(*pud_k))
436 		goto bad_area;
437 	if (!pud_present(*pud))
438 		set_pud(pud, *pud_k);
439 
440 	pmd = pmd_offset(pud, addr);
441 	pmd_k = pmd_offset(pud_k, addr);
442 
443 	/*
444 	 * On ARM one Linux PGD entry contains two hardware entries (see page
445 	 * tables layout in pgtable.h). We normally guarantee that we always
446 	 * fill both L1 entries. But create_mapping() doesn't follow the rule.
447 	 * It can create inidividual L1 entries, so here we have to call
448 	 * pmd_none() check for the entry really corresponded to address, not
449 	 * for the first of pair.
450 	 */
451 	index = (addr >> SECTION_SHIFT) & 1;
452 	if (pmd_none(pmd_k[index]))
453 		goto bad_area;
454 
455 	copy_pmd(pmd, pmd_k);
456 	return 0;
457 
458 bad_area:
459 	do_bad_area(addr, fsr, regs);
460 	return 0;
461 }
462 #else					/* CONFIG_MMU */
463 static int
464 do_translation_fault(unsigned long addr, unsigned int fsr,
465 		     struct pt_regs *regs)
466 {
467 	return 0;
468 }
469 #endif					/* CONFIG_MMU */
470 
471 /*
472  * Some section permission faults need to be handled gracefully.
473  * They can happen due to a __{get,put}_user during an oops.
474  */
475 static int
476 do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
477 {
478 	do_bad_area(addr, fsr, regs);
479 	return 0;
480 }
481 
482 /*
483  * This abort handler always returns "fault".
484  */
485 static int
486 do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
487 {
488 	return 1;
489 }
490 
491 static struct fsr_info {
492 	int	(*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
493 	int	sig;
494 	int	code;
495 	const char *name;
496 } fsr_info[] = {
497 	/*
498 	 * The following are the standard ARMv3 and ARMv4 aborts.  ARMv5
499 	 * defines these to be "precise" aborts.
500 	 */
501 	{ do_bad,		SIGSEGV, 0,		"vector exception"		   },
502 	{ do_bad,		SIGBUS,	 BUS_ADRALN,	"alignment exception"		   },
503 	{ do_bad,		SIGKILL, 0,		"terminal exception"		   },
504 	{ do_bad,		SIGBUS,	 BUS_ADRALN,	"alignment exception"		   },
505 	{ do_bad,		SIGBUS,	 0,		"external abort on linefetch"	   },
506 	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"section translation fault"	   },
507 	{ do_bad,		SIGBUS,	 0,		"external abort on linefetch"	   },
508 	{ do_page_fault,	SIGSEGV, SEGV_MAPERR,	"page translation fault"	   },
509 	{ do_bad,		SIGBUS,	 0,		"external abort on non-linefetch"  },
510 	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"section domain fault"		   },
511 	{ do_bad,		SIGBUS,	 0,		"external abort on non-linefetch"  },
512 	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"page domain fault"		   },
513 	{ do_bad,		SIGBUS,	 0,		"external abort on translation"	   },
514 	{ do_sect_fault,	SIGSEGV, SEGV_ACCERR,	"section permission fault"	   },
515 	{ do_bad,		SIGBUS,	 0,		"external abort on translation"	   },
516 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"page permission fault"		   },
517 	/*
518 	 * The following are "imprecise" aborts, which are signalled by bit
519 	 * 10 of the FSR, and may not be recoverable.  These are only
520 	 * supported if the CPU abort handler supports bit 10.
521 	 */
522 	{ do_bad,		SIGBUS,  0,		"unknown 16"			   },
523 	{ do_bad,		SIGBUS,  0,		"unknown 17"			   },
524 	{ do_bad,		SIGBUS,  0,		"unknown 18"			   },
525 	{ do_bad,		SIGBUS,  0,		"unknown 19"			   },
526 	{ do_bad,		SIGBUS,  0,		"lock abort"			   }, /* xscale */
527 	{ do_bad,		SIGBUS,  0,		"unknown 21"			   },
528 	{ do_bad,		SIGBUS,  BUS_OBJERR,	"imprecise external abort"	   }, /* xscale */
529 	{ do_bad,		SIGBUS,  0,		"unknown 23"			   },
530 	{ do_bad,		SIGBUS,  0,		"dcache parity error"		   }, /* xscale */
531 	{ do_bad,		SIGBUS,  0,		"unknown 25"			   },
532 	{ do_bad,		SIGBUS,  0,		"unknown 26"			   },
533 	{ do_bad,		SIGBUS,  0,		"unknown 27"			   },
534 	{ do_bad,		SIGBUS,  0,		"unknown 28"			   },
535 	{ do_bad,		SIGBUS,  0,		"unknown 29"			   },
536 	{ do_bad,		SIGBUS,  0,		"unknown 30"			   },
537 	{ do_bad,		SIGBUS,  0,		"unknown 31"			   }
538 };
539 
540 void __init
541 hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
542 		int sig, int code, const char *name)
543 {
544 	if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
545 		BUG();
546 
547 	fsr_info[nr].fn   = fn;
548 	fsr_info[nr].sig  = sig;
549 	fsr_info[nr].code = code;
550 	fsr_info[nr].name = name;
551 }
552 
553 /*
554  * Dispatch a data abort to the relevant handler.
555  */
556 asmlinkage void __exception
557 do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
558 {
559 	const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
560 	struct siginfo info;
561 
562 	if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
563 		return;
564 
565 	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
566 		inf->name, fsr, addr);
567 
568 	info.si_signo = inf->sig;
569 	info.si_errno = 0;
570 	info.si_code  = inf->code;
571 	info.si_addr  = (void __user *)addr;
572 	arm_notify_die("", regs, &info, fsr, 0);
573 }
574 
575 
576 static struct fsr_info ifsr_info[] = {
577 	{ do_bad,		SIGBUS,  0,		"unknown 0"			   },
578 	{ do_bad,		SIGBUS,  0,		"unknown 1"			   },
579 	{ do_bad,		SIGBUS,  0,		"debug event"			   },
580 	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"section access flag fault"	   },
581 	{ do_bad,		SIGBUS,  0,		"unknown 4"			   },
582 	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"section translation fault"	   },
583 	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"page access flag fault"	   },
584 	{ do_page_fault,	SIGSEGV, SEGV_MAPERR,	"page translation fault"	   },
585 	{ do_bad,		SIGBUS,	 0,		"external abort on non-linefetch"  },
586 	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"section domain fault"		   },
587 	{ do_bad,		SIGBUS,  0,		"unknown 10"			   },
588 	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"page domain fault"		   },
589 	{ do_bad,		SIGBUS,	 0,		"external abort on translation"	   },
590 	{ do_sect_fault,	SIGSEGV, SEGV_ACCERR,	"section permission fault"	   },
591 	{ do_bad,		SIGBUS,	 0,		"external abort on translation"	   },
592 	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"page permission fault"		   },
593 	{ do_bad,		SIGBUS,  0,		"unknown 16"			   },
594 	{ do_bad,		SIGBUS,  0,		"unknown 17"			   },
595 	{ do_bad,		SIGBUS,  0,		"unknown 18"			   },
596 	{ do_bad,		SIGBUS,  0,		"unknown 19"			   },
597 	{ do_bad,		SIGBUS,  0,		"unknown 20"			   },
598 	{ do_bad,		SIGBUS,  0,		"unknown 21"			   },
599 	{ do_bad,		SIGBUS,  0,		"unknown 22"			   },
600 	{ do_bad,		SIGBUS,  0,		"unknown 23"			   },
601 	{ do_bad,		SIGBUS,  0,		"unknown 24"			   },
602 	{ do_bad,		SIGBUS,  0,		"unknown 25"			   },
603 	{ do_bad,		SIGBUS,  0,		"unknown 26"			   },
604 	{ do_bad,		SIGBUS,  0,		"unknown 27"			   },
605 	{ do_bad,		SIGBUS,  0,		"unknown 28"			   },
606 	{ do_bad,		SIGBUS,  0,		"unknown 29"			   },
607 	{ do_bad,		SIGBUS,  0,		"unknown 30"			   },
608 	{ do_bad,		SIGBUS,  0,		"unknown 31"			   },
609 };
610 
611 void __init
612 hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
613 		 int sig, int code, const char *name)
614 {
615 	if (nr < 0 || nr >= ARRAY_SIZE(ifsr_info))
616 		BUG();
617 
618 	ifsr_info[nr].fn   = fn;
619 	ifsr_info[nr].sig  = sig;
620 	ifsr_info[nr].code = code;
621 	ifsr_info[nr].name = name;
622 }
623 
624 asmlinkage void __exception
625 do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
626 {
627 	const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
628 	struct siginfo info;
629 
630 	if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
631 		return;
632 
633 	printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
634 		inf->name, ifsr, addr);
635 
636 	info.si_signo = inf->sig;
637 	info.si_errno = 0;
638 	info.si_code  = inf->code;
639 	info.si_addr  = (void __user *)addr;
640 	arm_notify_die("", regs, &info, ifsr, 0);
641 }
642 
643 static int __init exceptions_init(void)
644 {
645 	if (cpu_architecture() >= CPU_ARCH_ARMv6) {
646 		hook_fault_code(4, do_translation_fault, SIGSEGV, SEGV_MAPERR,
647 				"I-cache maintenance fault");
648 	}
649 
650 	if (cpu_architecture() >= CPU_ARCH_ARMv7) {
651 		/*
652 		 * TODO: Access flag faults introduced in ARMv6K.
653 		 * Runtime check for 'K' extension is needed
654 		 */
655 		hook_fault_code(3, do_bad, SIGSEGV, SEGV_MAPERR,
656 				"section access flag fault");
657 		hook_fault_code(6, do_bad, SIGSEGV, SEGV_MAPERR,
658 				"section access flag fault");
659 	}
660 
661 	return 0;
662 }
663 
664 arch_initcall(exceptions_init);
665