blob: c97f7940cb9553d52ba3b6c711f2dab430aea110 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/module.h>
12#include <linux/signal.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/mm.h>
Russell King67306da2008-12-14 18:01:44 +000014#include <linux/hardirq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/init.h>
Nicolas Pitre25ce1dd2007-12-03 15:21:57 -050016#include <linux/kprobes.h>
Russell King33fa9b12008-09-06 11:35:55 +010017#include <linux/uaccess.h>
Nicolas Pitre252d4c22008-09-11 11:52:02 -040018#include <linux/page-flags.h>
Catalin Marinas412bb0a2009-07-24 12:37:09 +010019#include <linux/sched.h>
Russell King65cec8e2009-08-17 20:02:06 +010020#include <linux/highmem.h>
Jamie Iles7ada1892010-02-02 20:24:58 +010021#include <linux/perf_event.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
Jamie Iles5a567d72011-10-08 11:20:42 +010023#include <asm/exception.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <asm/pgtable.h>
David Howells9f97da72012-03-28 18:30:01 +010025#include <asm/system_misc.h>
26#include <asm/system_info.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <asm/tlbflush.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29#include "fault.h"
30
Catalin Marinas09529f72009-07-24 12:34:55 +010031#ifdef CONFIG_MMU
Nicolas Pitre25ce1dd2007-12-03 15:21:57 -050032
33#ifdef CONFIG_KPROBES
34static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
35{
36 int ret = 0;
37
38 if (!user_mode(regs)) {
39 /* kprobe_running() needs smp_processor_id() */
40 preempt_disable();
41 if (kprobe_running() && kprobe_fault_handler(regs, fsr))
42 ret = 1;
43 preempt_enable();
44 }
45
46 return ret;
47}
48#else
49static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
50{
51 return 0;
52}
53#endif
54
Linus Torvalds1da177e2005-04-16 15:20:36 -070055/*
56 * This is useful to dump out the page tables associated with
57 * 'addr' in mm 'mm'.
58 */
59void show_pte(struct mm_struct *mm, unsigned long addr)
60{
61 pgd_t *pgd;
62
63 if (!mm)
64 mm = &init_mm;
65
66 printk(KERN_ALERT "pgd = %p\n", mm->pgd);
67 pgd = pgd_offset(mm, addr);
Will Deacon29a38192011-02-15 14:31:37 +010068 printk(KERN_ALERT "[%08lx] *pgd=%08llx",
69 addr, (long long)pgd_val(*pgd));
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
71 do {
Russell King516295e2010-11-21 16:27:49 +000072 pud_t *pud;
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 pmd_t *pmd;
74 pte_t *pte;
75
76 if (pgd_none(*pgd))
77 break;
78
79 if (pgd_bad(*pgd)) {
80 printk("(bad)");
81 break;
82 }
83
Russell King516295e2010-11-21 16:27:49 +000084 pud = pud_offset(pgd, addr);
85 if (PTRS_PER_PUD != 1)
Catalin Marinas140d5dc2011-07-13 16:32:58 +010086 printk(", *pud=%08llx", (long long)pud_val(*pud));
Russell King516295e2010-11-21 16:27:49 +000087
88 if (pud_none(*pud))
89 break;
90
91 if (pud_bad(*pud)) {
92 printk("(bad)");
93 break;
94 }
95
96 pmd = pmd_offset(pud, addr);
Nicolas Pitreda46c792008-09-30 16:10:11 +010097 if (PTRS_PER_PMD != 1)
Will Deacon29a38192011-02-15 14:31:37 +010098 printk(", *pmd=%08llx", (long long)pmd_val(*pmd));
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 if (pmd_none(*pmd))
101 break;
102
103 if (pmd_bad(*pmd)) {
104 printk("(bad)");
105 break;
106 }
107
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 /* We must not map this if we have highmem enabled */
Nicolas Pitre252d4c22008-09-11 11:52:02 -0400109 if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
110 break;
111
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 pte = pte_offset_map(pmd, addr);
Will Deacon29a38192011-02-15 14:31:37 +0100113 printk(", *pte=%08llx", (long long)pte_val(*pte));
Catalin Marinasf7b81562011-11-22 17:30:31 +0000114#ifndef CONFIG_ARM_LPAE
Will Deacon29a38192011-02-15 14:31:37 +0100115 printk(", *ppte=%08llx",
116 (long long)pte_val(pte[PTE_HWTABLE_PTRS]));
Catalin Marinasf7b81562011-11-22 17:30:31 +0000117#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 pte_unmap(pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 } while(0);
120
121 printk("\n");
122}
Catalin Marinas09529f72009-07-24 12:34:55 +0100123#else /* CONFIG_MMU */
124void show_pte(struct mm_struct *mm, unsigned long addr)
125{ }
126#endif /* CONFIG_MMU */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
128/*
129 * Oops. The kernel tried to access some page that wasn't present.
130 */
131static void
132__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
133 struct pt_regs *regs)
134{
135 /*
136 * Are we prepared to handle this kernel fault?
137 */
138 if (fixup_exception(regs))
139 return;
140
141 /*
142 * No handler, we'll have to terminate things with extreme prejudice.
143 */
144 bust_spinlocks(1);
145 printk(KERN_ALERT
146 "Unable to handle kernel %s at virtual address %08lx\n",
147 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
148 "paging request", addr);
149
150 show_pte(mm, addr);
151 die("Oops", regs, fsr);
152 bust_spinlocks(0);
153 do_exit(SIGKILL);
154}
155
156/*
157 * Something tried to access memory that isn't in our memory map..
158 * User mode accesses just cause a SIGSEGV
159 */
160static void
161__do_user_fault(struct task_struct *tsk, unsigned long addr,
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700162 unsigned int fsr, unsigned int sig, int code,
163 struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164{
165 struct siginfo si;
166
167#ifdef CONFIG_DEBUG_USER
Javi Merinof5274c22012-02-06 15:45:36 +0100168 if (((user_debug & UDBG_SEGV) && (sig == SIGSEGV)) ||
169 ((user_debug & UDBG_BUS) && (sig == SIGBUS))) {
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700170 printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
171 tsk->comm, sig, addr, fsr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 show_pte(tsk->mm, addr);
173 show_regs(regs);
174 }
175#endif
176
177 tsk->thread.address = addr;
178 tsk->thread.error_code = fsr;
179 tsk->thread.trap_no = 14;
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700180 si.si_signo = sig;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 si.si_errno = 0;
182 si.si_code = code;
183 si.si_addr = (void __user *)addr;
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700184 force_sig_info(sig, &si, tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185}
186
Russell Kinge5beac32006-09-27 16:13:48 +0100187void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188{
Russell Kinge5beac32006-09-27 16:13:48 +0100189 struct task_struct *tsk = current;
190 struct mm_struct *mm = tsk->active_mm;
191
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 /*
193 * If we are in kernel mode at this point, we
194 * have no context to handle this fault with.
195 */
196 if (user_mode(regs))
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700197 __do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 else
199 __do_kernel_fault(mm, addr, fsr, regs);
200}
201
Catalin Marinas09529f72009-07-24 12:34:55 +0100202#ifdef CONFIG_MMU
Nick Piggin5c72fc52007-07-20 09:21:06 +0200203#define VM_FAULT_BADMAP 0x010000
204#define VM_FAULT_BADACCESS 0x020000
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
Russell Kingd374bf12009-09-20 12:53:01 +0100206/*
207 * Check that the permissions on the VMA allow for the fault which occurred.
208 * If we encountered a write fault, we must have write permission, otherwise
209 * we allow any permission.
210 */
211static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
212{
213 unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
214
215 if (fsr & FSR_WRITE)
216 mask = VM_WRITE;
Russell Kingdf297bf2009-09-20 13:18:47 +0100217 if (fsr & FSR_LNX_PF)
218 mask = VM_EXEC;
Russell Kingd374bf12009-09-20 12:53:01 +0100219
220 return vma->vm_flags & mask ? false : true;
221}
222
223static int __kprobes
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
Kautuk Consul8878a532011-11-27 17:49:50 +0100225 unsigned int flags, struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226{
227 struct vm_area_struct *vma;
Russell Kingd374bf12009-09-20 12:53:01 +0100228 int fault;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230 vma = find_vma(mm, addr);
231 fault = VM_FAULT_BADMAP;
Russell Kingd374bf12009-09-20 12:53:01 +0100232 if (unlikely(!vma))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 goto out;
Russell Kingd374bf12009-09-20 12:53:01 +0100234 if (unlikely(vma->vm_start > addr))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 goto check_stack;
236
237 /*
238 * Ok, we have a good vm_area for this
239 * memory access, so we can handle it.
240 */
241good_area:
Russell Kingd374bf12009-09-20 12:53:01 +0100242 if (access_error(fsr, vma)) {
243 fault = VM_FAULT_BADACCESS;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 goto out;
Russell Kingd374bf12009-09-20 12:53:01 +0100245 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
Kautuk Consul8878a532011-11-27 17:49:50 +0100247 return handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249check_stack:
Russell King9b61a4d2012-05-16 15:19:20 +0100250 /* Don't allow expansion below FIRST_USER_ADDRESS */
251 if (vma->vm_flags & VM_GROWSDOWN &&
252 addr >= FIRST_USER_ADDRESS && !expand_stack(vma, addr))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 goto good_area;
254out:
255 return fault;
256}
257
Nicolas Pitre785d3cd2007-12-03 15:27:56 -0500258static int __kprobes
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
260{
261 struct task_struct *tsk;
262 struct mm_struct *mm;
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700263 int fault, sig, code;
Kautuk Consul8878a532011-11-27 17:49:50 +0100264 int write = fsr & FSR_WRITE;
265 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
266 (write ? FAULT_FLAG_WRITE : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Nicolas Pitre25ce1dd2007-12-03 15:21:57 -0500268 if (notify_page_fault(regs, fsr))
269 return 0;
270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 tsk = current;
272 mm = tsk->mm;
273
Russell King02fe2842011-06-25 11:44:06 +0100274 /* Enable interrupts if they were enabled in the parent context. */
275 if (interrupts_enabled(regs))
276 local_irq_enable();
277
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 /*
279 * If we're in an interrupt or have no user
280 * context, we must not take the fault..
281 */
Peter Zijlstra6edaf682006-12-06 20:32:18 -0800282 if (in_atomic() || !mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 goto no_context;
284
Russell King840ff6a2005-09-20 17:52:13 +0100285 /*
286 * As per x86, we may deadlock here. However, since the kernel only
287 * validly references user space from well defined areas of the code,
288 * we can bug out early if this is from code which shouldn't.
289 */
290 if (!down_read_trylock(&mm->mmap_sem)) {
291 if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
292 goto no_context;
Kautuk Consul8878a532011-11-27 17:49:50 +0100293retry:
Russell King840ff6a2005-09-20 17:52:13 +0100294 down_read(&mm->mmap_sem);
Russell Kingbf4569922009-09-20 12:52:19 +0100295 } else {
296 /*
297 * The above down_read_trylock() might have succeeded in
298 * which case, we'll have missed the might_sleep() from
299 * down_read()
300 */
301 might_sleep();
Imre Deak1d212712009-10-05 13:40:44 +0100302#ifdef CONFIG_DEBUG_VM
303 if (!user_mode(regs) &&
304 !search_exception_tables(regs->ARM_pc))
305 goto no_context;
306#endif
Russell King840ff6a2005-09-20 17:52:13 +0100307 }
308
Kautuk Consul8878a532011-11-27 17:49:50 +0100309 fault = __do_page_fault(mm, addr, fsr, flags, tsk);
310
311 /* If we need to retry but a fatal signal is pending, handle the
312 * signal first. We do not need to release the mmap_sem because
313 * it would already be released in __lock_page_or_retry in
314 * mm/filemap.c. */
315 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
316 return 0;
317
318 /*
319 * Major/minor page fault accounting is only done on the
320 * initial attempt. If we go through a retry, it is extremely
321 * likely that the page will be found in page cache at that point.
322 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
Peter Zijlstraa8b0ca12011-06-27 14:41:57 +0200324 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
Kautuk Consuldff2aa72012-04-02 18:19:49 +0100325 if (!(fault & VM_FAULT_ERROR) && flags & FAULT_FLAG_ALLOW_RETRY) {
Kautuk Consul8878a532011-11-27 17:49:50 +0100326 if (fault & VM_FAULT_MAJOR) {
327 tsk->maj_flt++;
328 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
329 regs, addr);
330 } else {
331 tsk->min_flt++;
332 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
333 regs, addr);
334 }
335 if (fault & VM_FAULT_RETRY) {
336 /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
337 * of starvation. */
338 flags &= ~FAULT_FLAG_ALLOW_RETRY;
Shaohua Li45cac652012-10-08 16:32:19 -0700339 flags |= FAULT_FLAG_TRIED;
Kautuk Consul8878a532011-11-27 17:49:50 +0100340 goto retry;
341 }
342 }
343
344 up_read(&mm->mmap_sem);
Jamie Iles7ada1892010-02-02 20:24:58 +0100345
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 /*
Russell Kingff2afb92005-08-04 14:17:33 +0100347 * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 */
Nick Piggin5c72fc52007-07-20 09:21:06 +0200349 if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 return 0;
351
Russell Kingb42c6342009-09-20 12:47:40 +0100352 if (fault & VM_FAULT_OOM) {
353 /*
354 * We ran out of memory, call the OOM killer, and return to
355 * userspace (which will retry the fault, or kill us if we
356 * got oom-killed)
357 */
358 pagefault_out_of_memory();
359 return 0;
360 }
361
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 * If we are in kernel mode at this point, we
364 * have no context to handle this fault with.
365 */
366 if (!user_mode(regs))
367 goto no_context;
368
Nick Piggin83c54072007-07-19 01:47:05 -0700369 if (fault & VM_FAULT_SIGBUS) {
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700370 /*
371 * We had some memory, but were unable to
372 * successfully fix up this page fault.
373 */
374 sig = SIGBUS;
375 code = BUS_ADRERR;
Nick Piggin83c54072007-07-19 01:47:05 -0700376 } else {
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700377 /*
378 * Something tried to access memory that
379 * isn't in our memory map..
380 */
381 sig = SIGSEGV;
382 code = fault == VM_FAULT_BADACCESS ?
383 SEGV_ACCERR : SEGV_MAPERR;
akpm@osdl.org2d137c22005-04-16 15:23:55 -0700384 }
385
386 __do_user_fault(tsk, addr, fsr, sig, code, regs);
387 return 0;
388
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389no_context:
390 __do_kernel_fault(mm, addr, fsr, regs);
391 return 0;
392}
Catalin Marinas09529f72009-07-24 12:34:55 +0100393#else /* CONFIG_MMU */
394static int
395do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
396{
397 return 0;
398}
399#endif /* CONFIG_MMU */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400
401/*
402 * First Level Translation Fault Handler
403 *
404 * We enter here because the first level page table doesn't contain
405 * a valid entry for the address.
406 *
407 * If the address is in kernel space (>= TASK_SIZE), then we are
408 * probably faulting in the vmalloc() area.
409 *
410 * If the init_task's first level page tables contains the relevant
411 * entry, we copy the it to this task. If not, we send the process
412 * a signal, fixup the exception, or oops the kernel.
413 *
414 * NOTE! We MUST NOT take any locks for this case. We may be in an
415 * interrupt or a critical region, and should only copy the information
416 * from the master page table, nothing more.
417 */
Catalin Marinas09529f72009-07-24 12:34:55 +0100418#ifdef CONFIG_MMU
Nicolas Pitre785d3cd2007-12-03 15:27:56 -0500419static int __kprobes
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420do_translation_fault(unsigned long addr, unsigned int fsr,
421 struct pt_regs *regs)
422{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 unsigned int index;
424 pgd_t *pgd, *pgd_k;
Russell King516295e2010-11-21 16:27:49 +0000425 pud_t *pud, *pud_k;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 pmd_t *pmd, *pmd_k;
427
428 if (addr < TASK_SIZE)
429 return do_page_fault(addr, fsr, regs);
430
Anfei5e27fb72010-06-08 15:16:49 +0100431 if (user_mode(regs))
432 goto bad_area;
433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 index = pgd_index(addr);
435
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 pgd = cpu_get_pgd() + index;
437 pgd_k = init_mm.pgd + index;
438
439 if (pgd_none(*pgd_k))
440 goto bad_area;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 if (!pgd_present(*pgd))
442 set_pgd(pgd, *pgd_k);
443
Russell King516295e2010-11-21 16:27:49 +0000444 pud = pud_offset(pgd, addr);
445 pud_k = pud_offset(pgd_k, addr);
446
447 if (pud_none(*pud_k))
448 goto bad_area;
449 if (!pud_present(*pud))
450 set_pud(pud, *pud_k);
451
452 pmd = pmd_offset(pud, addr);
453 pmd_k = pmd_offset(pud_k, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
Catalin Marinasf7b81562011-11-22 17:30:31 +0000455#ifdef CONFIG_ARM_LPAE
456 /*
457 * Only one hardware entry per PMD with LPAE.
458 */
459 index = 0;
460#else
Kirill A. Shutemov33a9c412010-07-22 13:20:22 +0100461 /*
462 * On ARM one Linux PGD entry contains two hardware entries (see page
463 * tables layout in pgtable.h). We normally guarantee that we always
464 * fill both L1 entries. But create_mapping() doesn't follow the rule.
465 * It can create inidividual L1 entries, so here we have to call
466 * pmd_none() check for the entry really corresponded to address, not
467 * for the first of pair.
468 */
469 index = (addr >> SECTION_SHIFT) & 1;
Catalin Marinasf7b81562011-11-22 17:30:31 +0000470#endif
Kirill A. Shutemov33a9c412010-07-22 13:20:22 +0100471 if (pmd_none(pmd_k[index]))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 goto bad_area;
473
474 copy_pmd(pmd, pmd_k);
475 return 0;
476
477bad_area:
Russell Kinge5beac32006-09-27 16:13:48 +0100478 do_bad_area(addr, fsr, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 return 0;
480}
Catalin Marinas09529f72009-07-24 12:34:55 +0100481#else /* CONFIG_MMU */
482static int
483do_translation_fault(unsigned long addr, unsigned int fsr,
484 struct pt_regs *regs)
485{
486 return 0;
487}
488#endif /* CONFIG_MMU */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
490/*
491 * Some section permission faults need to be handled gracefully.
492 * They can happen due to a __{get,put}_user during an oops.
493 */
Steven Capper809e6602013-06-25 08:45:51 +0100494#ifndef CONFIG_ARM_LPAE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495static int
496do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
497{
Russell Kinge5beac32006-09-27 16:13:48 +0100498 do_bad_area(addr, fsr, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 return 0;
500}
Steven Capper809e6602013-06-25 08:45:51 +0100501#endif /* CONFIG_ARM_LPAE */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
503/*
504 * This abort handler always returns "fault".
505 */
506static int
507do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
508{
509 return 1;
510}
511
Catalin Marinas136848d2011-11-22 17:30:28 +0000512struct fsr_info {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 int (*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
514 int sig;
Russell Kingcfb08102005-06-30 11:06:49 +0100515 int code;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 const char *name;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517};
518
Catalin Marinas136848d2011-11-22 17:30:28 +0000519/* FSR definition */
Catalin Marinasf7b81562011-11-22 17:30:31 +0000520#ifdef CONFIG_ARM_LPAE
521#include "fsr-3level.c"
522#else
Catalin Marinas136848d2011-11-22 17:30:28 +0000523#include "fsr-2level.c"
Catalin Marinasf7b81562011-11-22 17:30:31 +0000524#endif
Catalin Marinas136848d2011-11-22 17:30:28 +0000525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526void __init
527hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
Kirill A. Shutemov6338a6a2010-07-22 13:18:19 +0100528 int sig, int code, const char *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529{
Kirill A. Shutemov6338a6a2010-07-22 13:18:19 +0100530 if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
531 BUG();
532
533 fsr_info[nr].fn = fn;
534 fsr_info[nr].sig = sig;
535 fsr_info[nr].code = code;
536 fsr_info[nr].name = name;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537}
538
539/*
540 * Dispatch a data abort to the relevant handler.
541 */
Russell King7ab3f8d2007-03-02 15:01:36 +0000542asmlinkage void __exception
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
544{
Russell Kingc88d6aa2009-09-20 12:41:58 +0100545 const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
Russell Kingcfb08102005-06-30 11:06:49 +0100546 struct siginfo info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
Russell Kingdf297bf2009-09-20 13:18:47 +0100548 if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 return;
550
551 printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
552 inf->name, fsr, addr);
Russell Kingcfb08102005-06-30 11:06:49 +0100553
554 info.si_signo = inf->sig;
555 info.si_errno = 0;
556 info.si_code = inf->code;
557 info.si_addr = (void __user *)addr;
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700558 arm_notify_die("", regs, &info, fsr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559}
560
Will Deacon3a4b5dc2010-09-03 10:39:59 +0100561void __init
562hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
563 int sig, int code, const char *name)
564{
565 if (nr < 0 || nr >= ARRAY_SIZE(ifsr_info))
566 BUG();
567
568 ifsr_info[nr].fn = fn;
569 ifsr_info[nr].sig = sig;
570 ifsr_info[nr].code = code;
571 ifsr_info[nr].name = name;
572}
573
Russell King7ab3f8d2007-03-02 15:01:36 +0000574asmlinkage void __exception
Kirill A. Shutemov4fb28472009-09-25 13:39:47 +0100575do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576{
Kirill A. Shutemovd25ef8b2009-09-25 13:40:49 +0100577 const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
578 struct siginfo info;
579
580 if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
581 return;
582
583 printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
584 inf->name, ifsr, addr);
585
586 info.si_signo = inf->sig;
587 info.si_errno = 0;
588 info.si_code = inf->code;
589 info.si_addr = (void __user *)addr;
590 arm_notify_die("", regs, &info, ifsr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591}
592
Catalin Marinasf7b81562011-11-22 17:30:31 +0000593#ifndef CONFIG_ARM_LPAE
Kirill A. Shutemov993bf4e2010-07-22 13:23:25 +0100594static int __init exceptions_init(void)
595{
596 if (cpu_architecture() >= CPU_ARCH_ARMv6) {
597 hook_fault_code(4, do_translation_fault, SIGSEGV, SEGV_MAPERR,
598 "I-cache maintenance fault");
599 }
600
Kirill A. Shutemovb8ab5392010-07-26 11:20:41 +0100601 if (cpu_architecture() >= CPU_ARCH_ARMv7) {
602 /*
603 * TODO: Access flag faults introduced in ARMv6K.
604 * Runtime check for 'K' extension is needed
605 */
606 hook_fault_code(3, do_bad, SIGSEGV, SEGV_MAPERR,
607 "section access flag fault");
608 hook_fault_code(6, do_bad, SIGSEGV, SEGV_MAPERR,
609 "section access flag fault");
610 }
611
Kirill A. Shutemov993bf4e2010-07-22 13:23:25 +0100612 return 0;
613}
614
615arch_initcall(exceptions_init);
Catalin Marinasf7b81562011-11-22 17:30:31 +0000616#endif