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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/arch/x86-64/mm/fault.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs. | |
6 | */ | |
7 | ||
1da177e4 LT |
8 | #include <linux/signal.h> |
9 | #include <linux/sched.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/errno.h> | |
12 | #include <linux/string.h> | |
13 | #include <linux/types.h> | |
14 | #include <linux/ptrace.h> | |
15 | #include <linux/mman.h> | |
16 | #include <linux/mm.h> | |
17 | #include <linux/smp.h> | |
1da177e4 LT |
18 | #include <linux/interrupt.h> |
19 | #include <linux/init.h> | |
20 | #include <linux/tty.h> | |
21 | #include <linux/vt_kern.h> /* For unblank_screen() */ | |
22 | #include <linux/compiler.h> | |
1eeb66a1 | 23 | #include <linux/vmalloc.h> |
1da177e4 | 24 | #include <linux/module.h> |
0f2fbdcb | 25 | #include <linux/kprobes.h> |
ab2bf0c1 | 26 | #include <linux/uaccess.h> |
1eeb66a1 | 27 | #include <linux/kdebug.h> |
1da177e4 LT |
28 | |
29 | #include <asm/system.h> | |
1da177e4 LT |
30 | #include <asm/pgalloc.h> |
31 | #include <asm/smp.h> | |
32 | #include <asm/tlbflush.h> | |
33 | #include <asm/proto.h> | |
1da177e4 | 34 | #include <asm-generic/sections.h> |
1da177e4 | 35 | |
66c58156 AK |
36 | /* Page fault error code bits */ |
37 | #define PF_PROT (1<<0) /* or no page found */ | |
38 | #define PF_WRITE (1<<1) | |
39 | #define PF_USER (1<<2) | |
40 | #define PF_RSVD (1<<3) | |
41 | #define PF_INSTR (1<<4) | |
42 | ||
74a0b576 CH |
43 | #ifdef CONFIG_KPROBES |
44 | static inline int notify_page_fault(struct pt_regs *regs) | |
1bd858a5 | 45 | { |
74a0b576 CH |
46 | int ret = 0; |
47 | ||
48 | /* kprobe_running() needs smp_processor_id() */ | |
49 | if (!user_mode(regs)) { | |
50 | preempt_disable(); | |
51 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
52 | ret = 1; | |
53 | preempt_enable(); | |
54 | } | |
1bd858a5 | 55 | |
74a0b576 | 56 | return ret; |
1bd858a5 | 57 | } |
74a0b576 CH |
58 | #else |
59 | static inline int notify_page_fault(struct pt_regs *regs) | |
1bd858a5 | 60 | { |
74a0b576 | 61 | return 0; |
1bd858a5 | 62 | } |
74a0b576 | 63 | #endif |
1bd858a5 | 64 | |
1da177e4 LT |
65 | /* Sometimes the CPU reports invalid exceptions on prefetch. |
66 | Check that here and ignore. | |
67 | Opcode checker based on code by Richard Brunner */ | |
68 | static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr, | |
69 | unsigned long error_code) | |
70 | { | |
ab2bf0c1 | 71 | unsigned char *instr; |
1da177e4 LT |
72 | int scan_more = 1; |
73 | int prefetch = 0; | |
f1290ec9 | 74 | unsigned char *max_instr; |
1da177e4 LT |
75 | |
76 | /* If it was a exec fault ignore */ | |
66c58156 | 77 | if (error_code & PF_INSTR) |
1da177e4 LT |
78 | return 0; |
79 | ||
dd2994f6 | 80 | instr = (unsigned char __user *)convert_rip_to_linear(current, regs); |
f1290ec9 | 81 | max_instr = instr + 15; |
1da177e4 | 82 | |
76381fee | 83 | if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE) |
1da177e4 LT |
84 | return 0; |
85 | ||
86 | while (scan_more && instr < max_instr) { | |
87 | unsigned char opcode; | |
88 | unsigned char instr_hi; | |
89 | unsigned char instr_lo; | |
90 | ||
ab2bf0c1 | 91 | if (probe_kernel_address(instr, opcode)) |
1da177e4 LT |
92 | break; |
93 | ||
94 | instr_hi = opcode & 0xf0; | |
95 | instr_lo = opcode & 0x0f; | |
96 | instr++; | |
97 | ||
98 | switch (instr_hi) { | |
99 | case 0x20: | |
100 | case 0x30: | |
101 | /* Values 0x26,0x2E,0x36,0x3E are valid x86 | |
102 | prefixes. In long mode, the CPU will signal | |
103 | invalid opcode if some of these prefixes are | |
104 | present so we will never get here anyway */ | |
105 | scan_more = ((instr_lo & 7) == 0x6); | |
106 | break; | |
107 | ||
108 | case 0x40: | |
109 | /* In AMD64 long mode, 0x40 to 0x4F are valid REX prefixes | |
110 | Need to figure out under what instruction mode the | |
111 | instruction was issued ... */ | |
112 | /* Could check the LDT for lm, but for now it's good | |
113 | enough to assume that long mode only uses well known | |
114 | segments or kernel. */ | |
76381fee | 115 | scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS); |
1da177e4 LT |
116 | break; |
117 | ||
118 | case 0x60: | |
119 | /* 0x64 thru 0x67 are valid prefixes in all modes. */ | |
120 | scan_more = (instr_lo & 0xC) == 0x4; | |
121 | break; | |
122 | case 0xF0: | |
123 | /* 0xF0, 0xF2, and 0xF3 are valid prefixes in all modes. */ | |
124 | scan_more = !instr_lo || (instr_lo>>1) == 1; | |
125 | break; | |
126 | case 0x00: | |
127 | /* Prefetch instruction is 0x0F0D or 0x0F18 */ | |
128 | scan_more = 0; | |
ab2bf0c1 | 129 | if (probe_kernel_address(instr, opcode)) |
1da177e4 LT |
130 | break; |
131 | prefetch = (instr_lo == 0xF) && | |
132 | (opcode == 0x0D || opcode == 0x18); | |
133 | break; | |
134 | default: | |
135 | scan_more = 0; | |
136 | break; | |
137 | } | |
138 | } | |
139 | return prefetch; | |
140 | } | |
141 | ||
142 | static int bad_address(void *p) | |
143 | { | |
144 | unsigned long dummy; | |
ab2bf0c1 | 145 | return probe_kernel_address((unsigned long *)p, dummy); |
1da177e4 LT |
146 | } |
147 | ||
148 | void dump_pagetable(unsigned long address) | |
149 | { | |
150 | pgd_t *pgd; | |
151 | pud_t *pud; | |
152 | pmd_t *pmd; | |
153 | pte_t *pte; | |
154 | ||
f51c9452 | 155 | pgd = (pgd_t *)read_cr3(); |
1da177e4 LT |
156 | |
157 | pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK); | |
158 | pgd += pgd_index(address); | |
1da177e4 | 159 | if (bad_address(pgd)) goto bad; |
d646bce4 | 160 | printk("PGD %lx ", pgd_val(*pgd)); |
1da177e4 LT |
161 | if (!pgd_present(*pgd)) goto ret; |
162 | ||
d2ae5b5f | 163 | pud = pud_offset(pgd, address); |
1da177e4 LT |
164 | if (bad_address(pud)) goto bad; |
165 | printk("PUD %lx ", pud_val(*pud)); | |
166 | if (!pud_present(*pud)) goto ret; | |
167 | ||
168 | pmd = pmd_offset(pud, address); | |
169 | if (bad_address(pmd)) goto bad; | |
170 | printk("PMD %lx ", pmd_val(*pmd)); | |
b1992df3 | 171 | if (!pmd_present(*pmd) || pmd_large(*pmd)) goto ret; |
1da177e4 LT |
172 | |
173 | pte = pte_offset_kernel(pmd, address); | |
174 | if (bad_address(pte)) goto bad; | |
175 | printk("PTE %lx", pte_val(*pte)); | |
176 | ret: | |
177 | printk("\n"); | |
178 | return; | |
179 | bad: | |
180 | printk("BAD\n"); | |
181 | } | |
182 | ||
183 | static const char errata93_warning[] = | |
184 | KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n" | |
185 | KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n" | |
186 | KERN_ERR "******* Please consider a BIOS update.\n" | |
187 | KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n"; | |
188 | ||
189 | /* Workaround for K8 erratum #93 & buggy BIOS. | |
190 | BIOS SMM functions are required to use a specific workaround | |
191 | to avoid corruption of the 64bit RIP register on C stepping K8. | |
192 | A lot of BIOS that didn't get tested properly miss this. | |
193 | The OS sees this as a page fault with the upper 32bits of RIP cleared. | |
194 | Try to work around it here. | |
195 | Note we only handle faults in kernel here. */ | |
196 | ||
197 | static int is_errata93(struct pt_regs *regs, unsigned long address) | |
198 | { | |
199 | static int warned; | |
65ea5b03 | 200 | if (address != regs->ip) |
1da177e4 LT |
201 | return 0; |
202 | if ((address >> 32) != 0) | |
203 | return 0; | |
204 | address |= 0xffffffffUL << 32; | |
205 | if ((address >= (u64)_stext && address <= (u64)_etext) || | |
206 | (address >= MODULES_VADDR && address <= MODULES_END)) { | |
207 | if (!warned) { | |
208 | printk(errata93_warning); | |
209 | warned = 1; | |
210 | } | |
65ea5b03 | 211 | regs->ip = address; |
1da177e4 LT |
212 | return 1; |
213 | } | |
214 | return 0; | |
215 | } | |
216 | ||
1da177e4 LT |
217 | static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs, |
218 | unsigned long error_code) | |
219 | { | |
1209140c | 220 | unsigned long flags = oops_begin(); |
6e3f3617 | 221 | struct task_struct *tsk; |
1209140c | 222 | |
1da177e4 LT |
223 | printk(KERN_ALERT "%s: Corrupted page table at address %lx\n", |
224 | current->comm, address); | |
225 | dump_pagetable(address); | |
6e3f3617 JB |
226 | tsk = current; |
227 | tsk->thread.cr2 = address; | |
228 | tsk->thread.trap_no = 14; | |
229 | tsk->thread.error_code = error_code; | |
22f5991c JB |
230 | if (__die("Bad pagetable", regs, error_code)) |
231 | regs = NULL; | |
232 | oops_end(flags, regs, SIGKILL); | |
1da177e4 LT |
233 | } |
234 | ||
235 | /* | |
f95190b2 | 236 | * Handle a fault on the vmalloc area |
3b9ba4d5 AK |
237 | * |
238 | * This assumes no large pages in there. | |
1da177e4 LT |
239 | */ |
240 | static int vmalloc_fault(unsigned long address) | |
241 | { | |
242 | pgd_t *pgd, *pgd_ref; | |
243 | pud_t *pud, *pud_ref; | |
244 | pmd_t *pmd, *pmd_ref; | |
245 | pte_t *pte, *pte_ref; | |
246 | ||
247 | /* Copy kernel mappings over when needed. This can also | |
248 | happen within a race in page table update. In the later | |
249 | case just flush. */ | |
250 | ||
251 | pgd = pgd_offset(current->mm ?: &init_mm, address); | |
252 | pgd_ref = pgd_offset_k(address); | |
253 | if (pgd_none(*pgd_ref)) | |
254 | return -1; | |
255 | if (pgd_none(*pgd)) | |
256 | set_pgd(pgd, *pgd_ref); | |
8c914cb7 | 257 | else |
46a82b2d | 258 | BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); |
1da177e4 LT |
259 | |
260 | /* Below here mismatches are bugs because these lower tables | |
261 | are shared */ | |
262 | ||
263 | pud = pud_offset(pgd, address); | |
264 | pud_ref = pud_offset(pgd_ref, address); | |
265 | if (pud_none(*pud_ref)) | |
266 | return -1; | |
46a82b2d | 267 | if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref)) |
1da177e4 LT |
268 | BUG(); |
269 | pmd = pmd_offset(pud, address); | |
270 | pmd_ref = pmd_offset(pud_ref, address); | |
271 | if (pmd_none(*pmd_ref)) | |
272 | return -1; | |
273 | if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref)) | |
274 | BUG(); | |
275 | pte_ref = pte_offset_kernel(pmd_ref, address); | |
276 | if (!pte_present(*pte_ref)) | |
277 | return -1; | |
278 | pte = pte_offset_kernel(pmd, address); | |
3b9ba4d5 AK |
279 | /* Don't use pte_page here, because the mappings can point |
280 | outside mem_map, and the NUMA hash lookup cannot handle | |
281 | that. */ | |
282 | if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref)) | |
1da177e4 | 283 | BUG(); |
1da177e4 LT |
284 | return 0; |
285 | } | |
286 | ||
abd4f750 | 287 | int show_unhandled_signals = 1; |
1da177e4 LT |
288 | |
289 | /* | |
290 | * This routine handles page faults. It determines the address, | |
291 | * and the problem, and then passes it off to one of the appropriate | |
292 | * routines. | |
1da177e4 | 293 | */ |
0f2fbdcb PP |
294 | asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, |
295 | unsigned long error_code) | |
1da177e4 LT |
296 | { |
297 | struct task_struct *tsk; | |
298 | struct mm_struct *mm; | |
299 | struct vm_area_struct * vma; | |
300 | unsigned long address; | |
83c54070 | 301 | int write, fault; |
1209140c | 302 | unsigned long flags; |
1da177e4 LT |
303 | siginfo_t info; |
304 | ||
143a5d32 PZ |
305 | /* |
306 | * We can fault from pretty much anywhere, with unknown IRQ state. | |
307 | */ | |
308 | trace_hardirqs_fixup(); | |
309 | ||
a9ba9a3b AV |
310 | tsk = current; |
311 | mm = tsk->mm; | |
312 | prefetchw(&mm->mmap_sem); | |
313 | ||
1da177e4 | 314 | /* get the address */ |
f51c9452 | 315 | address = read_cr2(); |
1da177e4 | 316 | |
1da177e4 LT |
317 | info.si_code = SEGV_MAPERR; |
318 | ||
319 | ||
320 | /* | |
321 | * We fault-in kernel-space virtual memory on-demand. The | |
322 | * 'reference' page table is init_mm.pgd. | |
323 | * | |
324 | * NOTE! We MUST NOT take any locks for this case. We may | |
325 | * be in an interrupt or a critical region, and should | |
326 | * only copy the information from the master page table, | |
327 | * nothing more. | |
328 | * | |
329 | * This verifies that the fault happens in kernel space | |
330 | * (error_code & 4) == 0, and that the fault was not a | |
8b1bde93 | 331 | * protection error (error_code & 9) == 0. |
1da177e4 | 332 | */ |
84929801 | 333 | if (unlikely(address >= TASK_SIZE64)) { |
f95190b2 AK |
334 | /* |
335 | * Don't check for the module range here: its PML4 | |
336 | * is always initialized because it's shared with the main | |
337 | * kernel text. Only vmalloc may need PML4 syncups. | |
338 | */ | |
66c58156 | 339 | if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) && |
f95190b2 | 340 | ((address >= VMALLOC_START && address < VMALLOC_END))) { |
8c914cb7 JB |
341 | if (vmalloc_fault(address) >= 0) |
342 | return; | |
1da177e4 | 343 | } |
74a0b576 | 344 | if (notify_page_fault(regs)) |
8c914cb7 | 345 | return; |
1da177e4 LT |
346 | /* |
347 | * Don't take the mm semaphore here. If we fixup a prefetch | |
348 | * fault we could otherwise deadlock. | |
349 | */ | |
350 | goto bad_area_nosemaphore; | |
351 | } | |
352 | ||
74a0b576 | 353 | if (notify_page_fault(regs)) |
8c914cb7 JB |
354 | return; |
355 | ||
65ea5b03 | 356 | if (likely(regs->flags & X86_EFLAGS_IF)) |
8c914cb7 JB |
357 | local_irq_enable(); |
358 | ||
66c58156 | 359 | if (unlikely(error_code & PF_RSVD)) |
1da177e4 LT |
360 | pgtable_bad(address, regs, error_code); |
361 | ||
362 | /* | |
363 | * If we're in an interrupt or have no user | |
364 | * context, we must not take the fault.. | |
365 | */ | |
366 | if (unlikely(in_atomic() || !mm)) | |
367 | goto bad_area_nosemaphore; | |
368 | ||
dbe3ed1c LT |
369 | /* |
370 | * User-mode registers count as a user access even for any | |
371 | * potential system fault or CPU buglet. | |
372 | */ | |
373 | if (user_mode_vm(regs)) | |
374 | error_code |= PF_USER; | |
375 | ||
1da177e4 LT |
376 | again: |
377 | /* When running in the kernel we expect faults to occur only to | |
378 | * addresses in user space. All other faults represent errors in the | |
676b1855 | 379 | * kernel and should generate an OOPS. Unfortunately, in the case of an |
80f7228b | 380 | * erroneous fault occurring in a code path which already holds mmap_sem |
1da177e4 LT |
381 | * we will deadlock attempting to validate the fault against the |
382 | * address space. Luckily the kernel only validly references user | |
383 | * space from well defined areas of code, which are listed in the | |
384 | * exceptions table. | |
385 | * | |
386 | * As the vast majority of faults will be valid we will only perform | |
676b1855 | 387 | * the source reference check when there is a possibility of a deadlock. |
1da177e4 LT |
388 | * Attempt to lock the address space, if we cannot we then validate the |
389 | * source. If this is invalid we can skip the address space check, | |
390 | * thus avoiding the deadlock. | |
391 | */ | |
392 | if (!down_read_trylock(&mm->mmap_sem)) { | |
66c58156 | 393 | if ((error_code & PF_USER) == 0 && |
65ea5b03 | 394 | !search_exception_tables(regs->ip)) |
1da177e4 LT |
395 | goto bad_area_nosemaphore; |
396 | down_read(&mm->mmap_sem); | |
397 | } | |
398 | ||
399 | vma = find_vma(mm, address); | |
400 | if (!vma) | |
401 | goto bad_area; | |
402 | if (likely(vma->vm_start <= address)) | |
403 | goto good_area; | |
404 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
405 | goto bad_area; | |
406 | if (error_code & 4) { | |
03fdc2c2 CE |
407 | /* Allow userspace just enough access below the stack pointer |
408 | * to let the 'enter' instruction work. | |
409 | */ | |
65ea5b03 | 410 | if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp) |
1da177e4 LT |
411 | goto bad_area; |
412 | } | |
413 | if (expand_stack(vma, address)) | |
414 | goto bad_area; | |
415 | /* | |
416 | * Ok, we have a good vm_area for this memory access, so | |
417 | * we can handle it.. | |
418 | */ | |
419 | good_area: | |
420 | info.si_code = SEGV_ACCERR; | |
421 | write = 0; | |
66c58156 | 422 | switch (error_code & (PF_PROT|PF_WRITE)) { |
1da177e4 LT |
423 | default: /* 3: write, present */ |
424 | /* fall through */ | |
66c58156 | 425 | case PF_WRITE: /* write, not present */ |
1da177e4 LT |
426 | if (!(vma->vm_flags & VM_WRITE)) |
427 | goto bad_area; | |
428 | write++; | |
429 | break; | |
66c58156 | 430 | case PF_PROT: /* read, present */ |
1da177e4 | 431 | goto bad_area; |
66c58156 | 432 | case 0: /* read, not present */ |
df67b3da | 433 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
1da177e4 LT |
434 | goto bad_area; |
435 | } | |
436 | ||
437 | /* | |
438 | * If for any reason at all we couldn't handle the fault, | |
439 | * make sure we exit gracefully rather than endlessly redo | |
440 | * the fault. | |
441 | */ | |
83c54070 NP |
442 | fault = handle_mm_fault(mm, vma, address, write); |
443 | if (unlikely(fault & VM_FAULT_ERROR)) { | |
444 | if (fault & VM_FAULT_OOM) | |
445 | goto out_of_memory; | |
446 | else if (fault & VM_FAULT_SIGBUS) | |
447 | goto do_sigbus; | |
448 | BUG(); | |
1da177e4 | 449 | } |
83c54070 NP |
450 | if (fault & VM_FAULT_MAJOR) |
451 | tsk->maj_flt++; | |
452 | else | |
453 | tsk->min_flt++; | |
1da177e4 LT |
454 | up_read(&mm->mmap_sem); |
455 | return; | |
456 | ||
457 | /* | |
458 | * Something tried to access memory that isn't in our memory map.. | |
459 | * Fix it, but check if it's kernel or user first.. | |
460 | */ | |
461 | bad_area: | |
462 | up_read(&mm->mmap_sem); | |
463 | ||
464 | bad_area_nosemaphore: | |
1da177e4 | 465 | /* User mode accesses just cause a SIGSEGV */ |
66c58156 | 466 | if (error_code & PF_USER) { |
e5e3c84b SR |
467 | |
468 | /* | |
469 | * It's possible to have interrupts off here. | |
470 | */ | |
471 | local_irq_enable(); | |
472 | ||
1da177e4 LT |
473 | if (is_prefetch(regs, address, error_code)) |
474 | return; | |
475 | ||
476 | /* Work around K8 erratum #100 K8 in compat mode | |
477 | occasionally jumps to illegal addresses >4GB. We | |
478 | catch this here in the page fault handler because | |
479 | these addresses are not reachable. Just detect this | |
480 | case and return. Any code segment in LDT is | |
481 | compatibility mode. */ | |
482 | if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) && | |
483 | (address >> 32)) | |
484 | return; | |
485 | ||
abd4f750 MAS |
486 | if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && |
487 | printk_ratelimit()) { | |
1da177e4 | 488 | printk( |
65ea5b03 | 489 | "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n", |
1da177e4 | 490 | tsk->pid > 1 ? KERN_INFO : KERN_EMERG, |
65ea5b03 PA |
491 | tsk->comm, tsk->pid, address, regs->ip, |
492 | regs->sp, error_code); | |
1da177e4 LT |
493 | } |
494 | ||
495 | tsk->thread.cr2 = address; | |
496 | /* Kernel addresses are always protection faults */ | |
497 | tsk->thread.error_code = error_code | (address >= TASK_SIZE); | |
498 | tsk->thread.trap_no = 14; | |
499 | info.si_signo = SIGSEGV; | |
500 | info.si_errno = 0; | |
501 | /* info.si_code has been set above */ | |
502 | info.si_addr = (void __user *)address; | |
503 | force_sig_info(SIGSEGV, &info, tsk); | |
504 | return; | |
505 | } | |
506 | ||
507 | no_context: | |
508 | ||
509 | /* Are we prepared to handle this kernel fault? */ | |
85f2adf1 | 510 | if (fixup_exception(regs)) { |
1da177e4 LT |
511 | return; |
512 | } | |
513 | ||
514 | /* | |
515 | * Hall of shame of CPU/BIOS bugs. | |
516 | */ | |
517 | ||
518 | if (is_prefetch(regs, address, error_code)) | |
519 | return; | |
520 | ||
521 | if (is_errata93(regs, address)) | |
522 | return; | |
523 | ||
524 | /* | |
525 | * Oops. The kernel tried to access some bad page. We'll have to | |
526 | * terminate things with extreme prejudice. | |
527 | */ | |
528 | ||
1209140c | 529 | flags = oops_begin(); |
1da177e4 LT |
530 | |
531 | if (address < PAGE_SIZE) | |
532 | printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); | |
533 | else | |
534 | printk(KERN_ALERT "Unable to handle kernel paging request"); | |
535 | printk(" at %016lx RIP: \n" KERN_ALERT,address); | |
65ea5b03 | 536 | printk_address(regs->ip); |
1da177e4 | 537 | dump_pagetable(address); |
6e3f3617 JB |
538 | tsk->thread.cr2 = address; |
539 | tsk->thread.trap_no = 14; | |
540 | tsk->thread.error_code = error_code; | |
22f5991c JB |
541 | if (__die("Oops", regs, error_code)) |
542 | regs = NULL; | |
1da177e4 LT |
543 | /* Executive summary in case the body of the oops scrolled away */ |
544 | printk(KERN_EMERG "CR2: %016lx\n", address); | |
22f5991c | 545 | oops_end(flags, regs, SIGKILL); |
1da177e4 LT |
546 | |
547 | /* | |
548 | * We ran out of memory, or some other thing happened to us that made | |
549 | * us unable to handle the page fault gracefully. | |
550 | */ | |
551 | out_of_memory: | |
552 | up_read(&mm->mmap_sem); | |
b460cbc5 | 553 | if (is_global_init(current)) { |
1da177e4 LT |
554 | yield(); |
555 | goto again; | |
556 | } | |
557 | printk("VM: killing process %s\n", tsk->comm); | |
558 | if (error_code & 4) | |
021daae2 | 559 | do_group_exit(SIGKILL); |
1da177e4 LT |
560 | goto no_context; |
561 | ||
562 | do_sigbus: | |
563 | up_read(&mm->mmap_sem); | |
564 | ||
565 | /* Kernel mode? Handle exceptions or die */ | |
66c58156 | 566 | if (!(error_code & PF_USER)) |
1da177e4 LT |
567 | goto no_context; |
568 | ||
569 | tsk->thread.cr2 = address; | |
570 | tsk->thread.error_code = error_code; | |
571 | tsk->thread.trap_no = 14; | |
572 | info.si_signo = SIGBUS; | |
573 | info.si_errno = 0; | |
574 | info.si_code = BUS_ADRERR; | |
575 | info.si_addr = (void __user *)address; | |
576 | force_sig_info(SIGBUS, &info, tsk); | |
577 | return; | |
578 | } | |
9e43e1b7 | 579 | |
8c914cb7 | 580 | DEFINE_SPINLOCK(pgd_lock); |
2bff7383 | 581 | LIST_HEAD(pgd_list); |
8c914cb7 JB |
582 | |
583 | void vmalloc_sync_all(void) | |
584 | { | |
585 | /* Note that races in the updates of insync and start aren't | |
586 | problematic: | |
587 | insync can only get set bits added, and updates to start are only | |
588 | improving performance (without affecting correctness if undone). */ | |
589 | static DECLARE_BITMAP(insync, PTRS_PER_PGD); | |
590 | static unsigned long start = VMALLOC_START & PGDIR_MASK; | |
591 | unsigned long address; | |
592 | ||
593 | for (address = start; address <= VMALLOC_END; address += PGDIR_SIZE) { | |
594 | if (!test_bit(pgd_index(address), insync)) { | |
595 | const pgd_t *pgd_ref = pgd_offset_k(address); | |
596 | struct page *page; | |
597 | ||
598 | if (pgd_none(*pgd_ref)) | |
599 | continue; | |
600 | spin_lock(&pgd_lock); | |
2bff7383 | 601 | list_for_each_entry(page, &pgd_list, lru) { |
8c914cb7 JB |
602 | pgd_t *pgd; |
603 | pgd = (pgd_t *)page_address(page) + pgd_index(address); | |
604 | if (pgd_none(*pgd)) | |
605 | set_pgd(pgd, *pgd_ref); | |
606 | else | |
46a82b2d | 607 | BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); |
8c914cb7 JB |
608 | } |
609 | spin_unlock(&pgd_lock); | |
610 | set_bit(pgd_index(address), insync); | |
611 | } | |
612 | if (address == start) | |
613 | start = address + PGDIR_SIZE; | |
614 | } | |
615 | /* Check that there is no need to do the same for the modules area. */ | |
616 | BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); | |
617 | BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == | |
618 | (__START_KERNEL & PGDIR_MASK))); | |
619 | } |