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Commit | Line | Data |
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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> |
3f07c014 | 16 | #include <linux/sched/signal.h> |
0f08f338 PM |
17 | #include <linux/hardirq.h> |
18 | #include <linux/kprobes.h> | |
cdd6c482 | 19 | #include <linux/perf_event.h> |
dbdb4e9f | 20 | #include <linux/kdebug.h> |
70ffdb93 | 21 | #include <linux/uaccess.h> |
e7cc9a73 | 22 | #include <asm/io_trapped.h> |
1da177e4 | 23 | #include <asm/mmu_context.h> |
db2e1fa3 | 24 | #include <asm/tlbflush.h> |
e839ca52 | 25 | #include <asm/traps.h> |
1da177e4 | 26 | |
7433ab77 PM |
27 | static inline int notify_page_fault(struct pt_regs *regs, int trap) |
28 | { | |
29 | int ret = 0; | |
30 | ||
c63c3105 | 31 | if (kprobes_built_in() && !user_mode(regs)) { |
7433ab77 PM |
32 | preempt_disable(); |
33 | if (kprobe_running() && kprobe_fault_handler(regs, trap)) | |
34 | ret = 1; | |
35 | preempt_enable(); | |
36 | } | |
7433ab77 PM |
37 | |
38 | return ret; | |
39 | } | |
40 | ||
dbdb4e9f PM |
41 | static void |
42 | force_sig_info_fault(int si_signo, int si_code, unsigned long address, | |
43 | struct task_struct *tsk) | |
44 | { | |
45 | siginfo_t info; | |
46 | ||
47 | info.si_signo = si_signo; | |
48 | info.si_errno = 0; | |
49 | info.si_code = si_code; | |
50 | info.si_addr = (void __user *)address; | |
51 | ||
52 | force_sig_info(si_signo, &info, tsk); | |
53 | } | |
54 | ||
45c0e0e2 SM |
55 | /* |
56 | * This is useful to dump out the page tables associated with | |
57 | * 'addr' in mm 'mm'. | |
58 | */ | |
59 | static void show_pte(struct mm_struct *mm, unsigned long addr) | |
60 | { | |
61 | pgd_t *pgd; | |
62 | ||
90eed7d8 | 63 | if (mm) { |
45c0e0e2 | 64 | pgd = mm->pgd; |
90eed7d8 | 65 | } else { |
45c0e0e2 SM |
66 | pgd = get_TTB(); |
67 | ||
90eed7d8 PM |
68 | if (unlikely(!pgd)) |
69 | pgd = swapper_pg_dir; | |
70 | } | |
71 | ||
45c0e0e2 SM |
72 | printk(KERN_ALERT "pgd = %p\n", pgd); |
73 | pgd += pgd_index(addr); | |
74 | printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr, | |
28080329 | 75 | (u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd)); |
45c0e0e2 SM |
76 | |
77 | do { | |
78 | pud_t *pud; | |
79 | pmd_t *pmd; | |
80 | pte_t *pte; | |
81 | ||
82 | if (pgd_none(*pgd)) | |
83 | break; | |
84 | ||
85 | if (pgd_bad(*pgd)) { | |
86 | printk("(bad)"); | |
87 | break; | |
88 | } | |
89 | ||
90 | pud = pud_offset(pgd, addr); | |
91 | if (PTRS_PER_PUD != 1) | |
28080329 | 92 | printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2), |
45c0e0e2 SM |
93 | (u64)pud_val(*pud)); |
94 | ||
95 | if (pud_none(*pud)) | |
96 | break; | |
97 | ||
98 | if (pud_bad(*pud)) { | |
99 | printk("(bad)"); | |
100 | break; | |
101 | } | |
102 | ||
103 | pmd = pmd_offset(pud, addr); | |
104 | if (PTRS_PER_PMD != 1) | |
28080329 | 105 | printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2), |
45c0e0e2 SM |
106 | (u64)pmd_val(*pmd)); |
107 | ||
108 | if (pmd_none(*pmd)) | |
109 | break; | |
110 | ||
111 | if (pmd_bad(*pmd)) { | |
112 | printk("(bad)"); | |
113 | break; | |
114 | } | |
115 | ||
116 | /* We must not map this if we have highmem enabled */ | |
117 | if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT))) | |
118 | break; | |
119 | ||
120 | pte = pte_offset_kernel(pmd, addr); | |
28080329 PM |
121 | printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2), |
122 | (u64)pte_val(*pte)); | |
45c0e0e2 SM |
123 | } while (0); |
124 | ||
125 | printk("\n"); | |
126 | } | |
127 | ||
0f60bb25 PM |
128 | static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address) |
129 | { | |
130 | unsigned index = pgd_index(address); | |
131 | pgd_t *pgd_k; | |
132 | pud_t *pud, *pud_k; | |
133 | pmd_t *pmd, *pmd_k; | |
134 | ||
135 | pgd += index; | |
136 | pgd_k = init_mm.pgd + index; | |
137 | ||
138 | if (!pgd_present(*pgd_k)) | |
139 | return NULL; | |
140 | ||
141 | pud = pud_offset(pgd, address); | |
142 | pud_k = pud_offset(pgd_k, address); | |
143 | if (!pud_present(*pud_k)) | |
144 | return NULL; | |
145 | ||
5d9b4b19 MF |
146 | if (!pud_present(*pud)) |
147 | set_pud(pud, *pud_k); | |
148 | ||
0f60bb25 PM |
149 | pmd = pmd_offset(pud, address); |
150 | pmd_k = pmd_offset(pud_k, address); | |
151 | if (!pmd_present(*pmd_k)) | |
152 | return NULL; | |
153 | ||
154 | if (!pmd_present(*pmd)) | |
155 | set_pmd(pmd, *pmd_k); | |
05dd2cd3 MF |
156 | else { |
157 | /* | |
158 | * The page tables are fully synchronised so there must | |
159 | * be another reason for the fault. Return NULL here to | |
160 | * signal that we have not taken care of the fault. | |
161 | */ | |
0f60bb25 | 162 | BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k)); |
05dd2cd3 MF |
163 | return NULL; |
164 | } | |
0f60bb25 PM |
165 | |
166 | return pmd_k; | |
167 | } | |
168 | ||
d8fd35fc PM |
169 | #ifdef CONFIG_SH_STORE_QUEUES |
170 | #define __FAULT_ADDR_LIMIT P3_ADDR_MAX | |
171 | #else | |
172 | #define __FAULT_ADDR_LIMIT VMALLOC_END | |
173 | #endif | |
174 | ||
0f60bb25 PM |
175 | /* |
176 | * Handle a fault on the vmalloc or module mapping area | |
177 | */ | |
178 | static noinline int vmalloc_fault(unsigned long address) | |
179 | { | |
180 | pgd_t *pgd_k; | |
181 | pmd_t *pmd_k; | |
182 | pte_t *pte_k; | |
183 | ||
c3e0af98 | 184 | /* Make sure we are in vmalloc/module/P3 area: */ |
d8fd35fc | 185 | if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT)) |
0f60bb25 PM |
186 | return -1; |
187 | ||
188 | /* | |
189 | * Synchronize this task's top level page-table | |
190 | * with the 'reference' page table. | |
191 | * | |
192 | * Do _not_ use "current" here. We might be inside | |
193 | * an interrupt in the middle of a task switch.. | |
194 | */ | |
195 | pgd_k = get_TTB(); | |
05dd2cd3 | 196 | pmd_k = vmalloc_sync_one(pgd_k, address); |
0f60bb25 PM |
197 | if (!pmd_k) |
198 | return -1; | |
199 | ||
200 | pte_k = pte_offset_kernel(pmd_k, address); | |
201 | if (!pte_present(*pte_k)) | |
202 | return -1; | |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
dbdb4e9f PM |
207 | static void |
208 | show_fault_oops(struct pt_regs *regs, unsigned long address) | |
209 | { | |
210 | if (!oops_may_print()) | |
211 | return; | |
212 | ||
213 | printk(KERN_ALERT "BUG: unable to handle kernel "); | |
214 | if (address < PAGE_SIZE) | |
215 | printk(KERN_CONT "NULL pointer dereference"); | |
216 | else | |
217 | printk(KERN_CONT "paging request"); | |
218 | ||
219 | printk(KERN_CONT " at %08lx\n", address); | |
220 | printk(KERN_ALERT "PC:"); | |
221 | printk_address(regs->pc, 1); | |
222 | ||
223 | show_pte(NULL, address); | |
224 | } | |
225 | ||
226 | static noinline void | |
5a1dc78a | 227 | no_context(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
228 | unsigned long address) |
229 | { | |
230 | /* Are we prepared to handle this kernel fault? */ | |
231 | if (fixup_exception(regs)) | |
232 | return; | |
233 | ||
234 | if (handle_trapped_io(regs, address)) | |
235 | return; | |
236 | ||
237 | /* | |
238 | * Oops. The kernel tried to access some bad page. We'll have to | |
239 | * terminate things with extreme prejudice. | |
240 | */ | |
241 | bust_spinlocks(1); | |
242 | ||
243 | show_fault_oops(regs, address); | |
244 | ||
5a1dc78a | 245 | die("Oops", regs, error_code); |
dbdb4e9f PM |
246 | bust_spinlocks(0); |
247 | do_exit(SIGKILL); | |
248 | } | |
249 | ||
250 | static void | |
5a1dc78a | 251 | __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
252 | unsigned long address, int si_code) |
253 | { | |
254 | struct task_struct *tsk = current; | |
255 | ||
256 | /* User mode accesses just cause a SIGSEGV */ | |
257 | if (user_mode(regs)) { | |
258 | /* | |
259 | * It's possible to have interrupts off here: | |
260 | */ | |
261 | local_irq_enable(); | |
262 | ||
263 | force_sig_info_fault(SIGSEGV, si_code, address, tsk); | |
264 | ||
265 | return; | |
266 | } | |
267 | ||
5a1dc78a | 268 | no_context(regs, error_code, address); |
dbdb4e9f PM |
269 | } |
270 | ||
271 | static noinline void | |
5a1dc78a | 272 | bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
273 | unsigned long address) |
274 | { | |
5a1dc78a | 275 | __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR); |
dbdb4e9f PM |
276 | } |
277 | ||
278 | static void | |
5a1dc78a | 279 | __bad_area(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
280 | unsigned long address, int si_code) |
281 | { | |
282 | struct mm_struct *mm = current->mm; | |
283 | ||
284 | /* | |
285 | * Something tried to access memory that isn't in our memory map.. | |
286 | * Fix it, but check if it's kernel or user first.. | |
287 | */ | |
288 | up_read(&mm->mmap_sem); | |
289 | ||
5a1dc78a | 290 | __bad_area_nosemaphore(regs, error_code, address, si_code); |
dbdb4e9f PM |
291 | } |
292 | ||
293 | static noinline void | |
5a1dc78a | 294 | bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address) |
dbdb4e9f | 295 | { |
5a1dc78a | 296 | __bad_area(regs, error_code, address, SEGV_MAPERR); |
dbdb4e9f PM |
297 | } |
298 | ||
299 | static noinline void | |
5a1dc78a | 300 | bad_area_access_error(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
301 | unsigned long address) |
302 | { | |
5a1dc78a | 303 | __bad_area(regs, error_code, address, SEGV_ACCERR); |
dbdb4e9f PM |
304 | } |
305 | ||
dbdb4e9f | 306 | static void |
5a1dc78a | 307 | do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address) |
dbdb4e9f PM |
308 | { |
309 | struct task_struct *tsk = current; | |
310 | struct mm_struct *mm = tsk->mm; | |
311 | ||
312 | up_read(&mm->mmap_sem); | |
313 | ||
314 | /* Kernel mode? Handle exceptions or die: */ | |
315 | if (!user_mode(regs)) | |
5a1dc78a | 316 | no_context(regs, error_code, address); |
dbdb4e9f PM |
317 | |
318 | force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk); | |
319 | } | |
320 | ||
321 | static noinline int | |
5a1dc78a | 322 | mm_fault_error(struct pt_regs *regs, unsigned long error_code, |
dbdb4e9f PM |
323 | unsigned long address, unsigned int fault) |
324 | { | |
325 | /* | |
326 | * Pagefault was interrupted by SIGKILL. We have no reason to | |
327 | * continue pagefault. | |
328 | */ | |
329 | if (fatal_signal_pending(current)) { | |
330 | if (!(fault & VM_FAULT_RETRY)) | |
331 | up_read(¤t->mm->mmap_sem); | |
332 | if (!user_mode(regs)) | |
5a1dc78a | 333 | no_context(regs, error_code, address); |
dbdb4e9f PM |
334 | return 1; |
335 | } | |
336 | ||
337 | if (!(fault & VM_FAULT_ERROR)) | |
338 | return 0; | |
339 | ||
340 | if (fault & VM_FAULT_OOM) { | |
341 | /* Kernel mode? Handle exceptions or die: */ | |
342 | if (!user_mode(regs)) { | |
343 | up_read(¤t->mm->mmap_sem); | |
5a1dc78a | 344 | no_context(regs, error_code, address); |
dbdb4e9f PM |
345 | return 1; |
346 | } | |
c2d23f91 | 347 | up_read(¤t->mm->mmap_sem); |
dbdb4e9f | 348 | |
c2d23f91 DR |
349 | /* |
350 | * We ran out of memory, call the OOM killer, and return the | |
351 | * userspace (which will retry the fault, or kill us if we got | |
352 | * oom-killed): | |
353 | */ | |
354 | pagefault_out_of_memory(); | |
dbdb4e9f PM |
355 | } else { |
356 | if (fault & VM_FAULT_SIGBUS) | |
5a1dc78a | 357 | do_sigbus(regs, error_code, address); |
33692f27 LT |
358 | else if (fault & VM_FAULT_SIGSEGV) |
359 | bad_area(regs, error_code, address); | |
dbdb4e9f PM |
360 | else |
361 | BUG(); | |
362 | } | |
363 | ||
364 | return 1; | |
365 | } | |
366 | ||
28080329 | 367 | static inline int access_error(int error_code, struct vm_area_struct *vma) |
dbdb4e9f | 368 | { |
28080329 | 369 | if (error_code & FAULT_CODE_WRITE) { |
dbdb4e9f PM |
370 | /* write, present and write, not present: */ |
371 | if (unlikely(!(vma->vm_flags & VM_WRITE))) | |
372 | return 1; | |
373 | return 0; | |
374 | } | |
375 | ||
28080329 PM |
376 | /* ITLB miss on NX page */ |
377 | if (unlikely((error_code & FAULT_CODE_ITLB) && | |
378 | !(vma->vm_flags & VM_EXEC))) | |
379 | return 1; | |
380 | ||
dbdb4e9f PM |
381 | /* read, not present: */ |
382 | if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))) | |
383 | return 1; | |
384 | ||
385 | return 0; | |
386 | } | |
387 | ||
0f60bb25 PM |
388 | static int fault_in_kernel_space(unsigned long address) |
389 | { | |
390 | return address >= TASK_SIZE; | |
391 | } | |
392 | ||
1da177e4 LT |
393 | /* |
394 | * This routine handles page faults. It determines the address, | |
395 | * and the problem, and then passes it off to one of the appropriate | |
396 | * routines. | |
397 | */ | |
b5a1bcbe | 398 | asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, |
5a1dc78a | 399 | unsigned long error_code, |
b5a1bcbe | 400 | unsigned long address) |
1da177e4 | 401 | { |
0f60bb25 | 402 | unsigned long vec; |
1da177e4 LT |
403 | struct task_struct *tsk; |
404 | struct mm_struct *mm; | |
405 | struct vm_area_struct * vma; | |
83c54070 | 406 | int fault; |
759496ba | 407 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; |
1da177e4 | 408 | |
1da177e4 | 409 | tsk = current; |
0f60bb25 | 410 | mm = tsk->mm; |
0f60bb25 | 411 | vec = lookup_exception_vector(); |
1da177e4 | 412 | |
0f60bb25 PM |
413 | /* |
414 | * We fault-in kernel-space virtual memory on-demand. The | |
415 | * 'reference' page table is init_mm.pgd. | |
416 | * | |
417 | * NOTE! We MUST NOT take any locks for this case. We may | |
418 | * be in an interrupt or a critical region, and should | |
419 | * only copy the information from the master page table, | |
420 | * nothing more. | |
421 | */ | |
422 | if (unlikely(fault_in_kernel_space(address))) { | |
423 | if (vmalloc_fault(address) >= 0) | |
99a596f9 | 424 | return; |
0f60bb25 | 425 | if (notify_page_fault(regs, vec)) |
96e14e54 | 426 | return; |
99a596f9 | 427 | |
5a1dc78a | 428 | bad_area_nosemaphore(regs, error_code, address); |
dbdb4e9f | 429 | return; |
99a596f9 SM |
430 | } |
431 | ||
0f60bb25 | 432 | if (unlikely(notify_page_fault(regs, vec))) |
7433ab77 PM |
433 | return; |
434 | ||
f2fb4e4f | 435 | /* Only enable interrupts if they were on before the fault */ |
7433ab77 | 436 | if ((regs->sr & SR_IMASK) != SR_IMASK) |
f2fb4e4f | 437 | local_irq_enable(); |
f2fb4e4f | 438 | |
a8b0ca17 | 439 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
f2fb4e4f | 440 | |
1da177e4 | 441 | /* |
0f60bb25 | 442 | * If we're in an interrupt, have no user context or are running |
70ffdb93 | 443 | * with pagefaults disabled then we must not take the fault: |
1da177e4 | 444 | */ |
70ffdb93 | 445 | if (unlikely(faulthandler_disabled() || !mm)) { |
5a1dc78a | 446 | bad_area_nosemaphore(regs, error_code, address); |
dbdb4e9f PM |
447 | return; |
448 | } | |
1da177e4 | 449 | |
11fd9824 | 450 | retry: |
1da177e4 LT |
451 | down_read(&mm->mmap_sem); |
452 | ||
453 | vma = find_vma(mm, address); | |
dbdb4e9f | 454 | if (unlikely(!vma)) { |
5a1dc78a | 455 | bad_area(regs, error_code, address); |
dbdb4e9f PM |
456 | return; |
457 | } | |
458 | if (likely(vma->vm_start <= address)) | |
1da177e4 | 459 | goto good_area; |
dbdb4e9f | 460 | if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) { |
5a1dc78a | 461 | bad_area(regs, error_code, address); |
dbdb4e9f PM |
462 | return; |
463 | } | |
464 | if (unlikely(expand_stack(vma, address))) { | |
5a1dc78a | 465 | bad_area(regs, error_code, address); |
dbdb4e9f PM |
466 | return; |
467 | } | |
0f60bb25 PM |
468 | |
469 | /* | |
470 | * Ok, we have a good vm_area for this memory access, so | |
471 | * we can handle it.. | |
472 | */ | |
1da177e4 | 473 | good_area: |
5a1dc78a PM |
474 | if (unlikely(access_error(error_code, vma))) { |
475 | bad_area_access_error(regs, error_code, address); | |
dbdb4e9f | 476 | return; |
1da177e4 LT |
477 | } |
478 | ||
5a1dc78a PM |
479 | set_thread_fault_code(error_code); |
480 | ||
759496ba JW |
481 | if (user_mode(regs)) |
482 | flags |= FAULT_FLAG_USER; | |
483 | if (error_code & FAULT_CODE_WRITE) | |
484 | flags |= FAULT_FLAG_WRITE; | |
485 | ||
1da177e4 LT |
486 | /* |
487 | * If for any reason at all we couldn't handle the fault, | |
488 | * make sure we exit gracefully rather than endlessly redo | |
489 | * the fault. | |
490 | */ | |
dcddffd4 | 491 | fault = handle_mm_fault(vma, address, flags); |
11fd9824 | 492 | |
dbdb4e9f | 493 | if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR))) |
5a1dc78a | 494 | if (mm_fault_error(regs, error_code, address, fault)) |
dbdb4e9f | 495 | return; |
11fd9824 KC |
496 | |
497 | if (flags & FAULT_FLAG_ALLOW_RETRY) { | |
498 | if (fault & VM_FAULT_MAJOR) { | |
499 | tsk->maj_flt++; | |
500 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, | |
501 | regs, address); | |
502 | } else { | |
503 | tsk->min_flt++; | |
504 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, | |
505 | regs, address); | |
506 | } | |
507 | if (fault & VM_FAULT_RETRY) { | |
508 | flags &= ~FAULT_FLAG_ALLOW_RETRY; | |
45cac65b | 509 | flags |= FAULT_FLAG_TRIED; |
11fd9824 KC |
510 | |
511 | /* | |
512 | * No need to up_read(&mm->mmap_sem) as we would | |
513 | * have already released it in __lock_page_or_retry | |
514 | * in mm/filemap.c. | |
515 | */ | |
516 | goto retry; | |
517 | } | |
7433ab77 | 518 | } |
1da177e4 LT |
519 | |
520 | up_read(&mm->mmap_sem); | |
1da177e4 | 521 | } |