Commit | Line | Data |
---|---|---|
26ff6c11 PM |
1 | /* |
2 | * Page fault handler for SH with an MMU. | |
1da177e4 | 3 | * |
1da177e4 | 4 | * Copyright (C) 1999 Niibe Yutaka |
dbdb4e9f | 5 | * Copyright (C) 2003 - 2012 Paul Mundt |
1da177e4 LT |
6 | * |
7 | * Based on linux/arch/i386/mm/fault.c: | |
8 | * Copyright (C) 1995 Linus Torvalds | |
26ff6c11 PM |
9 | * |
10 | * This file is subject to the terms and conditions of the GNU General Public | |
11 | * License. See the file "COPYING" in the main directory of this archive | |
12 | * for more details. | |
1da177e4 | 13 | */ |
1da177e4 | 14 | #include <linux/kernel.h> |
1da177e4 | 15 | #include <linux/mm.h> |
0f08f338 PM |
16 | #include <linux/hardirq.h> |
17 | #include <linux/kprobes.h> | |
cdd6c482 | 18 | #include <linux/perf_event.h> |
dbdb4e9f | 19 | #include <linux/kdebug.h> |
70ffdb93 | 20 | #include <linux/uaccess.h> |
e7cc9a73 | 21 | #include <asm/io_trapped.h> |
1da177e4 | 22 | #include <asm/mmu_context.h> |
db2e1fa3 | 23 | #include <asm/tlbflush.h> |
e839ca52 | 24 | #include <asm/traps.h> |
1da177e4 | 25 | |
7433ab77 PM |
26 | static inline int notify_page_fault(struct pt_regs *regs, int trap) |
27 | { | |
28 | int ret = 0; | |
29 | ||
c63c3105 | 30 | if (kprobes_built_in() && !user_mode(regs)) { |
7433ab77 PM |
31 | preempt_disable(); |
32 | if (kprobe_running() && kprobe_fault_handler(regs, trap)) | |
33 | ret = 1; | |
34 | preempt_enable(); | |
35 | } | |
7433ab77 PM |
36 | |
37 | return ret; | |
38 | } | |
39 | ||
dbdb4e9f PM |
40 | static void |
41 | force_sig_info_fault(int si_signo, int si_code, unsigned long address, | |
42 | struct task_struct *tsk) | |
43 | { | |
44 | siginfo_t info; | |
45 | ||
46 | info.si_signo = si_signo; | |
47 | info.si_errno = 0; | |
48 | info.si_code = si_code; | |
49 | info.si_addr = (void __user *)address; | |
50 | ||
51 | force_sig_info(si_signo, &info, tsk); | |
52 | } | |
53 | ||
45c0e0e2 SM |
54 | /* |
55 | * This is useful to dump out the page tables associated with | |
56 | * 'addr' in mm 'mm'. | |
57 | */ | |
58 | static void show_pte(struct mm_struct *mm, unsigned long addr) | |
59 | { | |
60 | pgd_t *pgd; | |
61 | ||
90eed7d8 | 62 | if (mm) { |
45c0e0e2 | 63 | pgd = mm->pgd; |
90eed7d8 | 64 | } else { |
45c0e0e2 SM |
65 | pgd = get_TTB(); |
66 | ||
90eed7d8 PM |
67 | if (unlikely(!pgd)) |
68 | pgd = swapper_pg_dir; | |
69 | } | |
70 | ||
45c0e0e2 SM |
71 | printk(KERN_ALERT "pgd = %p\n", pgd); |
72 | pgd += pgd_index(addr); | |
73 | printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr, | |
28080329 | 74 | (u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd)); |
45c0e0e2 SM |
75 | |
76 | do { | |
77 | pud_t *pud; | |
78 | pmd_t *pmd; | |
79 | pte_t *pte; | |
80 | ||
81 | if (pgd_none(*pgd)) | |
82 | break; | |
83 | ||
84 | if (pgd_bad(*pgd)) { | |
85 | printk("(bad)"); | |
86 | break; | |
87 | } | |
88 | ||
89 | pud = pud_offset(pgd, addr); | |
90 | if (PTRS_PER_PUD != 1) | |
28080329 | 91 | printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2), |
45c0e0e2 SM |
92 | (u64)pud_val(*pud)); |
93 | ||
94 | if (pud_none(*pud)) | |
95 | break; | |
96 | ||
97 | if (pud_bad(*pud)) { | |
98 | printk("(bad)"); | |
99 | break; | |
100 | } | |
101 | ||
102 | pmd = pmd_offset(pud, addr); | |
103 | if (PTRS_PER_PMD != 1) | |
28080329 | 104 | printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2), |
45c0e0e2 SM |
105 | (u64)pmd_val(*pmd)); |
106 | ||
107 | if (pmd_none(*pmd)) | |
108 | break; | |
109 | ||
110 | if (pmd_bad(*pmd)) { | |
111 | printk("(bad)"); | |
112 | break; | |
113 | } | |
114 | ||
115 | /* We must not map this if we have highmem enabled */ | |
116 | if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT))) | |
117 | break; | |
118 | ||
119 | pte = pte_offset_kernel(pmd, addr); | |
28080329 PM |
120 | printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2), |
121 | (u64)pte_val(*pte)); | |
45c0e0e2 SM |
122 | } while (0); |
123 | ||
124 | printk("\n"); | |
125 | } | |
126 | ||
0f60bb25 PM |
127 | static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address) |
128 | { | |
129 | unsigned index = pgd_index(address); | |
130 | pgd_t *pgd_k; | |
131 | pud_t *pud, *pud_k; | |
132 | pmd_t *pmd, *pmd_k; | |
133 | ||
134 | pgd += index; | |
135 | pgd_k = init_mm.pgd + index; | |
136 | ||
137 | if (!pgd_present(*pgd_k)) | |
138 | return NULL; | |
139 | ||
140 | pud = pud_offset(pgd, address); | |
141 | pud_k = pud_offset(pgd_k, address); | |
142 | if (!pud_present(*pud_k)) | |
143 | return NULL; | |
144 | ||
5d9b4b19 MF |
145 | if (!pud_present(*pud)) |
146 | set_pud(pud, *pud_k); | |
147 | ||
0f60bb25 PM |
148 | pmd = pmd_offset(pud, address); |
149 | pmd_k = pmd_offset(pud_k, address); | |
150 | if (!pmd_present(*pmd_k)) | |
151 | return NULL; | |
152 | ||
153 | if (!pmd_present(*pmd)) | |
154 | set_pmd(pmd, *pmd_k); | |
05dd2cd3 MF |
155 | else { |
156 | /* | |
157 | * The page tables are fully synchronised so there must | |
158 | * be another reason for the fault. Return NULL here to | |
159 | * signal that we have not taken care of the fault. | |
160 | */ | |
0f60bb25 | 161 | BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k)); |
05dd2cd3 MF |
162 | return NULL; |
163 | } | |
0f60bb25 PM |
164 | |
165 | return pmd_k; | |
166 | } | |
167 | ||
d8fd35fc PM |
168 | #ifdef CONFIG_SH_STORE_QUEUES |
169 | #define __FAULT_ADDR_LIMIT P3_ADDR_MAX | |
170 | #else | |
171 | #define __FAULT_ADDR_LIMIT VMALLOC_END | |
172 | #endif | |
173 | ||
0f60bb25 PM |
174 | /* |
175 | * Handle a fault on the vmalloc or module mapping area | |
176 | */ | |
177 | static noinline int vmalloc_fault(unsigned long address) | |
178 | { | |
179 | pgd_t *pgd_k; | |
180 | pmd_t *pmd_k; | |
181 | pte_t *pte_k; | |
182 | ||
c3e0af98 | 183 | /* Make sure we are in vmalloc/module/P3 area: */ |
d8fd35fc | 184 | if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT)) |
0f60bb25 PM |
185 | return -1; |
186 | ||
187 | /* | |
188 | * Synchronize this task's top level page-table | |
189 | * with the 'reference' page table. | |
190 | * | |
191 | * Do _not_ use "current" here. We might be inside | |
192 | * an interrupt in the middle of a task switch.. | |
193 | */ | |
194 | pgd_k = get_TTB(); | |
05dd2cd3 | 195 | pmd_k = vmalloc_sync_one(pgd_k, address); |
0f60bb25 PM |
196 | if (!pmd_k) |
197 | return -1; | |
198 | ||
199 | pte_k = pte_offset_kernel(pmd_k, address); | |
200 | if (!pte_present(*pte_k)) | |
201 | return -1; | |
202 | ||
203 | return 0; | |
204 | } | |
205 | ||
dbdb4e9f PM |
206 | static void |
207 | show_fault_oops(struct pt_regs *regs, unsigned long address) | |
208 | { | |
209 | if (!oops_may_print()) | |
210 | return; | |
211 | ||
212 | printk(KERN_ALERT "BUG: unable to handle kernel "); | |
213 | if (address < PAGE_SIZE) | |
214 | printk(KERN_CONT "NULL pointer dereference"); | |
215 | else | |
216 | printk(KERN_CONT "paging request"); | |
217 | ||
218 | printk(KERN_CONT " at %08lx\n", address); | |
219 | printk(KERN_ALERT "PC:"); | |
220 | printk_address(regs->pc, 1); | |
221 | ||
222 | show_pte(NULL, address); | |
223 | } | |
224 | ||
225 | static noinline void | |
5a1dc78a | 226 | no_context(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
227 | unsigned long address) |
228 | { | |
229 | /* Are we prepared to handle this kernel fault? */ | |
230 | if (fixup_exception(regs)) | |
231 | return; | |
232 | ||
233 | if (handle_trapped_io(regs, address)) | |
234 | return; | |
235 | ||
236 | /* | |
237 | * Oops. The kernel tried to access some bad page. We'll have to | |
238 | * terminate things with extreme prejudice. | |
239 | */ | |
240 | bust_spinlocks(1); | |
241 | ||
242 | show_fault_oops(regs, address); | |
243 | ||
5a1dc78a | 244 | die("Oops", regs, error_code); |
dbdb4e9f PM |
245 | bust_spinlocks(0); |
246 | do_exit(SIGKILL); | |
247 | } | |
248 | ||
249 | static void | |
5a1dc78a | 250 | __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
251 | unsigned long address, int si_code) |
252 | { | |
253 | struct task_struct *tsk = current; | |
254 | ||
255 | /* User mode accesses just cause a SIGSEGV */ | |
256 | if (user_mode(regs)) { | |
257 | /* | |
258 | * It's possible to have interrupts off here: | |
259 | */ | |
260 | local_irq_enable(); | |
261 | ||
262 | force_sig_info_fault(SIGSEGV, si_code, address, tsk); | |
263 | ||
264 | return; | |
265 | } | |
266 | ||
5a1dc78a | 267 | no_context(regs, error_code, address); |
dbdb4e9f PM |
268 | } |
269 | ||
270 | static noinline void | |
5a1dc78a | 271 | bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
272 | unsigned long address) |
273 | { | |
5a1dc78a | 274 | __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR); |
dbdb4e9f PM |
275 | } |
276 | ||
277 | static void | |
5a1dc78a | 278 | __bad_area(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
279 | unsigned long address, int si_code) |
280 | { | |
281 | struct mm_struct *mm = current->mm; | |
282 | ||
283 | /* | |
284 | * Something tried to access memory that isn't in our memory map.. | |
285 | * Fix it, but check if it's kernel or user first.. | |
286 | */ | |
287 | up_read(&mm->mmap_sem); | |
288 | ||
5a1dc78a | 289 | __bad_area_nosemaphore(regs, error_code, address, si_code); |
dbdb4e9f PM |
290 | } |
291 | ||
292 | static noinline void | |
5a1dc78a | 293 | bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address) |
dbdb4e9f | 294 | { |
5a1dc78a | 295 | __bad_area(regs, error_code, address, SEGV_MAPERR); |
dbdb4e9f PM |
296 | } |
297 | ||
298 | static noinline void | |
5a1dc78a | 299 | bad_area_access_error(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
300 | unsigned long address) |
301 | { | |
5a1dc78a | 302 | __bad_area(regs, error_code, address, SEGV_ACCERR); |
dbdb4e9f PM |
303 | } |
304 | ||
dbdb4e9f | 305 | static void |
5a1dc78a | 306 | do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address) |
dbdb4e9f PM |
307 | { |
308 | struct task_struct *tsk = current; | |
309 | struct mm_struct *mm = tsk->mm; | |
310 | ||
311 | up_read(&mm->mmap_sem); | |
312 | ||
313 | /* Kernel mode? Handle exceptions or die: */ | |
314 | if (!user_mode(regs)) | |
5a1dc78a | 315 | no_context(regs, error_code, address); |
dbdb4e9f PM |
316 | |
317 | force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk); | |
318 | } | |
319 | ||
320 | static noinline int | |
5a1dc78a | 321 | mm_fault_error(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
322 | unsigned long address, unsigned int fault) |
323 | { | |
324 | /* | |
325 | * Pagefault was interrupted by SIGKILL. We have no reason to | |
326 | * continue pagefault. | |
327 | */ | |
328 | if (fatal_signal_pending(current)) { | |
329 | if (!(fault & VM_FAULT_RETRY)) | |
330 | up_read(¤t->mm->mmap_sem); | |
331 | if (!user_mode(regs)) | |
5a1dc78a | 332 | no_context(regs, error_code, address); |
dbdb4e9f PM |
333 | return 1; |
334 | } | |
335 | ||
336 | if (!(fault & VM_FAULT_ERROR)) | |
337 | return 0; | |
338 | ||
339 | if (fault & VM_FAULT_OOM) { | |
340 | /* Kernel mode? Handle exceptions or die: */ | |
341 | if (!user_mode(regs)) { | |
342 | up_read(¤t->mm->mmap_sem); | |
5a1dc78a | 343 | no_context(regs, error_code, address); |
dbdb4e9f PM |
344 | return 1; |
345 | } | |
c2d23f91 | 346 | up_read(¤t->mm->mmap_sem); |
dbdb4e9f | 347 | |
c2d23f91 DR |
348 | /* |
349 | * We ran out of memory, call the OOM killer, and return the | |
350 | * userspace (which will retry the fault, or kill us if we got | |
351 | * oom-killed): | |
352 | */ | |
353 | pagefault_out_of_memory(); | |
dbdb4e9f PM |
354 | } else { |
355 | if (fault & VM_FAULT_SIGBUS) | |
5a1dc78a | 356 | do_sigbus(regs, error_code, address); |
33692f27 LT |
357 | else if (fault & VM_FAULT_SIGSEGV) |
358 | bad_area(regs, error_code, address); | |
dbdb4e9f PM |
359 | else |
360 | BUG(); | |
361 | } | |
362 | ||
363 | return 1; | |
364 | } | |
365 | ||
28080329 | 366 | static inline int access_error(int error_code, struct vm_area_struct *vma) |
dbdb4e9f | 367 | { |
28080329 | 368 | if (error_code & FAULT_CODE_WRITE) { |
dbdb4e9f PM |
369 | /* write, present and write, not present: */ |
370 | if (unlikely(!(vma->vm_flags & VM_WRITE))) | |
371 | return 1; | |
372 | return 0; | |
373 | } | |
374 | ||
28080329 PM |
375 | /* ITLB miss on NX page */ |
376 | if (unlikely((error_code & FAULT_CODE_ITLB) && | |
377 | !(vma->vm_flags & VM_EXEC))) | |
378 | return 1; | |
379 | ||
dbdb4e9f PM |
380 | /* read, not present: */ |
381 | if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))) | |
382 | return 1; | |
383 | ||
384 | return 0; | |
385 | } | |
386 | ||
0f60bb25 PM |
387 | static int fault_in_kernel_space(unsigned long address) |
388 | { | |
389 | return address >= TASK_SIZE; | |
390 | } | |
391 | ||
1da177e4 LT |
392 | /* |
393 | * This routine handles page faults. It determines the address, | |
394 | * and the problem, and then passes it off to one of the appropriate | |
395 | * routines. | |
396 | */ | |
b5a1bcbe | 397 | asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, |
5a1dc78a | 398 | unsigned long error_code, |
b5a1bcbe | 399 | unsigned long address) |
1da177e4 | 400 | { |
0f60bb25 | 401 | unsigned long vec; |
1da177e4 LT |
402 | struct task_struct *tsk; |
403 | struct mm_struct *mm; | |
404 | struct vm_area_struct * vma; | |
83c54070 | 405 | int fault; |
759496ba | 406 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
1da177e4 | 407 | |
1da177e4 | 408 | tsk = current; |
0f60bb25 | 409 | mm = tsk->mm; |
0f60bb25 | 410 | vec = lookup_exception_vector(); |
1da177e4 | 411 | |
0f60bb25 PM |
412 | /* |
413 | * We fault-in kernel-space virtual memory on-demand. The | |
414 | * 'reference' page table is init_mm.pgd. | |
415 | * | |
416 | * NOTE! We MUST NOT take any locks for this case. We may | |
417 | * be in an interrupt or a critical region, and should | |
418 | * only copy the information from the master page table, | |
419 | * nothing more. | |
420 | */ | |
421 | if (unlikely(fault_in_kernel_space(address))) { | |
422 | if (vmalloc_fault(address) >= 0) | |
99a596f9 | 423 | return; |
0f60bb25 | 424 | if (notify_page_fault(regs, vec)) |
96e14e54 | 425 | return; |
99a596f9 | 426 | |
5a1dc78a | 427 | bad_area_nosemaphore(regs, error_code, address); |
dbdb4e9f | 428 | return; |
99a596f9 SM |
429 | } |
430 | ||
0f60bb25 | 431 | if (unlikely(notify_page_fault(regs, vec))) |
7433ab77 PM |
432 | return; |
433 | ||
f2fb4e4f | 434 | /* Only enable interrupts if they were on before the fault */ |
7433ab77 | 435 | if ((regs->sr & SR_IMASK) != SR_IMASK) |
f2fb4e4f | 436 | local_irq_enable(); |
f2fb4e4f | 437 | |
a8b0ca17 | 438 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
f2fb4e4f | 439 | |
1da177e4 | 440 | /* |
0f60bb25 | 441 | * If we're in an interrupt, have no user context or are running |
70ffdb93 | 442 | * with pagefaults disabled then we must not take the fault: |
1da177e4 | 443 | */ |
70ffdb93 | 444 | if (unlikely(faulthandler_disabled() || !mm)) { |
5a1dc78a | 445 | bad_area_nosemaphore(regs, error_code, address); |
dbdb4e9f PM |
446 | return; |
447 | } | |
1da177e4 | 448 | |
11fd9824 | 449 | retry: |
1da177e4 LT |
450 | down_read(&mm->mmap_sem); |
451 | ||
452 | vma = find_vma(mm, address); | |
dbdb4e9f | 453 | if (unlikely(!vma)) { |
5a1dc78a | 454 | bad_area(regs, error_code, address); |
dbdb4e9f PM |
455 | return; |
456 | } | |
457 | if (likely(vma->vm_start <= address)) | |
1da177e4 | 458 | goto good_area; |
dbdb4e9f | 459 | if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) { |
5a1dc78a | 460 | bad_area(regs, error_code, address); |
dbdb4e9f PM |
461 | return; |
462 | } | |
463 | if (unlikely(expand_stack(vma, address))) { | |
5a1dc78a | 464 | bad_area(regs, error_code, address); |
dbdb4e9f PM |
465 | return; |
466 | } | |
0f60bb25 PM |
467 | |
468 | /* | |
469 | * Ok, we have a good vm_area for this memory access, so | |
470 | * we can handle it.. | |
471 | */ | |
1da177e4 | 472 | good_area: |
5a1dc78a PM |
473 | if (unlikely(access_error(error_code, vma))) { |
474 | bad_area_access_error(regs, error_code, address); | |
dbdb4e9f | 475 | return; |
1da177e4 LT |
476 | } |
477 | ||
5a1dc78a PM |
478 | set_thread_fault_code(error_code); |
479 | ||
759496ba JW |
480 | if (user_mode(regs)) |
481 | flags |= FAULT_FLAG_USER; | |
482 | if (error_code & FAULT_CODE_WRITE) | |
483 | flags |= FAULT_FLAG_WRITE; | |
484 | ||
1da177e4 LT |
485 | /* |
486 | * If for any reason at all we couldn't handle the fault, | |
487 | * make sure we exit gracefully rather than endlessly redo | |
488 | * the fault. | |
489 | */ | |
11fd9824 KC |
490 | fault = handle_mm_fault(mm, vma, address, flags); |
491 | ||
dbdb4e9f | 492 | if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR))) |
5a1dc78a | 493 | if (mm_fault_error(regs, error_code, address, fault)) |
dbdb4e9f | 494 | return; |
11fd9824 KC |
495 | |
496 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
497 | if (fault & VM_FAULT_MAJOR) { | |
498 | tsk->maj_flt++; | |
499 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, | |
500 | regs, address); | |
501 | } else { | |
502 | tsk->min_flt++; | |
503 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, | |
504 | regs, address); | |
505 | } | |
506 | if (fault & VM_FAULT_RETRY) { | |
507 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
45cac65b | 508 | flags |= FAULT_FLAG_TRIED; |
11fd9824 KC |
509 | |
510 | /* | |
511 | * No need to up_read(&mm->mmap_sem) as we would | |
512 | * have already released it in __lock_page_or_retry | |
513 | * in mm/filemap.c. | |
514 | */ | |
515 | goto retry; | |
516 | } | |
7433ab77 | 517 | } |
1da177e4 LT |
518 | |
519 | up_read(&mm->mmap_sem); | |
1da177e4 | 520 | } |