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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> |
74a0b576 | 28 | #include <linux/kprobes.h> |
1da177e4 LT |
29 | |
30 | #include <asm/system.h> | |
1da177e4 LT |
31 | #include <asm/pgalloc.h> |
32 | #include <asm/smp.h> | |
33 | #include <asm/tlbflush.h> | |
34 | #include <asm/proto.h> | |
1da177e4 | 35 | #include <asm-generic/sections.h> |
1da177e4 | 36 | |
66c58156 AK |
37 | /* Page fault error code bits */ |
38 | #define PF_PROT (1<<0) /* or no page found */ | |
39 | #define PF_WRITE (1<<1) | |
40 | #define PF_USER (1<<2) | |
41 | #define PF_RSVD (1<<3) | |
42 | #define PF_INSTR (1<<4) | |
43 | ||
74a0b576 CH |
44 | #ifdef CONFIG_KPROBES |
45 | static inline int notify_page_fault(struct pt_regs *regs) | |
1bd858a5 | 46 | { |
74a0b576 CH |
47 | int ret = 0; |
48 | ||
49 | /* kprobe_running() needs smp_processor_id() */ | |
50 | if (!user_mode(regs)) { | |
51 | preempt_disable(); | |
52 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
53 | ret = 1; | |
54 | preempt_enable(); | |
55 | } | |
1bd858a5 | 56 | |
74a0b576 | 57 | return ret; |
1bd858a5 | 58 | } |
74a0b576 CH |
59 | #else |
60 | static inline int notify_page_fault(struct pt_regs *regs) | |
1bd858a5 | 61 | { |
74a0b576 | 62 | return 0; |
1bd858a5 | 63 | } |
74a0b576 | 64 | #endif |
1bd858a5 | 65 | |
1da177e4 LT |
66 | /* Sometimes the CPU reports invalid exceptions on prefetch. |
67 | Check that here and ignore. | |
68 | Opcode checker based on code by Richard Brunner */ | |
69 | static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr, | |
70 | unsigned long error_code) | |
71 | { | |
ab2bf0c1 | 72 | unsigned char *instr; |
1da177e4 LT |
73 | int scan_more = 1; |
74 | int prefetch = 0; | |
f1290ec9 | 75 | unsigned char *max_instr; |
1da177e4 LT |
76 | |
77 | /* If it was a exec fault ignore */ | |
66c58156 | 78 | if (error_code & PF_INSTR) |
1da177e4 LT |
79 | return 0; |
80 | ||
dd2994f6 | 81 | instr = (unsigned char __user *)convert_rip_to_linear(current, regs); |
f1290ec9 | 82 | max_instr = instr + 15; |
1da177e4 | 83 | |
76381fee | 84 | if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE) |
1da177e4 LT |
85 | return 0; |
86 | ||
87 | while (scan_more && instr < max_instr) { | |
88 | unsigned char opcode; | |
89 | unsigned char instr_hi; | |
90 | unsigned char instr_lo; | |
91 | ||
ab2bf0c1 | 92 | if (probe_kernel_address(instr, opcode)) |
1da177e4 LT |
93 | break; |
94 | ||
95 | instr_hi = opcode & 0xf0; | |
96 | instr_lo = opcode & 0x0f; | |
97 | instr++; | |
98 | ||
99 | switch (instr_hi) { | |
100 | case 0x20: | |
101 | case 0x30: | |
102 | /* Values 0x26,0x2E,0x36,0x3E are valid x86 | |
103 | prefixes. In long mode, the CPU will signal | |
104 | invalid opcode if some of these prefixes are | |
105 | present so we will never get here anyway */ | |
106 | scan_more = ((instr_lo & 7) == 0x6); | |
107 | break; | |
108 | ||
109 | case 0x40: | |
110 | /* In AMD64 long mode, 0x40 to 0x4F are valid REX prefixes | |
111 | Need to figure out under what instruction mode the | |
112 | instruction was issued ... */ | |
113 | /* Could check the LDT for lm, but for now it's good | |
114 | enough to assume that long mode only uses well known | |
115 | segments or kernel. */ | |
76381fee | 116 | scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS); |
1da177e4 LT |
117 | break; |
118 | ||
119 | case 0x60: | |
120 | /* 0x64 thru 0x67 are valid prefixes in all modes. */ | |
121 | scan_more = (instr_lo & 0xC) == 0x4; | |
122 | break; | |
123 | case 0xF0: | |
124 | /* 0xF0, 0xF2, and 0xF3 are valid prefixes in all modes. */ | |
125 | scan_more = !instr_lo || (instr_lo>>1) == 1; | |
126 | break; | |
127 | case 0x00: | |
128 | /* Prefetch instruction is 0x0F0D or 0x0F18 */ | |
129 | scan_more = 0; | |
ab2bf0c1 | 130 | if (probe_kernel_address(instr, opcode)) |
1da177e4 LT |
131 | break; |
132 | prefetch = (instr_lo == 0xF) && | |
133 | (opcode == 0x0D || opcode == 0x18); | |
134 | break; | |
135 | default: | |
136 | scan_more = 0; | |
137 | break; | |
138 | } | |
139 | } | |
140 | return prefetch; | |
141 | } | |
142 | ||
143 | static int bad_address(void *p) | |
144 | { | |
145 | unsigned long dummy; | |
ab2bf0c1 | 146 | return probe_kernel_address((unsigned long *)p, dummy); |
1da177e4 LT |
147 | } |
148 | ||
149 | void dump_pagetable(unsigned long address) | |
150 | { | |
151 | pgd_t *pgd; | |
152 | pud_t *pud; | |
153 | pmd_t *pmd; | |
154 | pte_t *pte; | |
155 | ||
f51c9452 | 156 | pgd = (pgd_t *)read_cr3(); |
1da177e4 LT |
157 | |
158 | pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK); | |
159 | pgd += pgd_index(address); | |
1da177e4 | 160 | if (bad_address(pgd)) goto bad; |
d646bce4 | 161 | printk("PGD %lx ", pgd_val(*pgd)); |
1da177e4 LT |
162 | if (!pgd_present(*pgd)) goto ret; |
163 | ||
d2ae5b5f | 164 | pud = pud_offset(pgd, address); |
1da177e4 LT |
165 | if (bad_address(pud)) goto bad; |
166 | printk("PUD %lx ", pud_val(*pud)); | |
167 | if (!pud_present(*pud)) goto ret; | |
168 | ||
169 | pmd = pmd_offset(pud, address); | |
170 | if (bad_address(pmd)) goto bad; | |
171 | printk("PMD %lx ", pmd_val(*pmd)); | |
172 | if (!pmd_present(*pmd)) goto ret; | |
173 | ||
174 | pte = pte_offset_kernel(pmd, address); | |
175 | if (bad_address(pte)) goto bad; | |
176 | printk("PTE %lx", pte_val(*pte)); | |
177 | ret: | |
178 | printk("\n"); | |
179 | return; | |
180 | bad: | |
181 | printk("BAD\n"); | |
182 | } | |
183 | ||
184 | static const char errata93_warning[] = | |
185 | KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n" | |
186 | KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n" | |
187 | KERN_ERR "******* Please consider a BIOS update.\n" | |
188 | KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n"; | |
189 | ||
190 | /* Workaround for K8 erratum #93 & buggy BIOS. | |
191 | BIOS SMM functions are required to use a specific workaround | |
192 | to avoid corruption of the 64bit RIP register on C stepping K8. | |
193 | A lot of BIOS that didn't get tested properly miss this. | |
194 | The OS sees this as a page fault with the upper 32bits of RIP cleared. | |
195 | Try to work around it here. | |
196 | Note we only handle faults in kernel here. */ | |
197 | ||
198 | static int is_errata93(struct pt_regs *regs, unsigned long address) | |
199 | { | |
200 | static int warned; | |
201 | if (address != regs->rip) | |
202 | return 0; | |
203 | if ((address >> 32) != 0) | |
204 | return 0; | |
205 | address |= 0xffffffffUL << 32; | |
206 | if ((address >= (u64)_stext && address <= (u64)_etext) || | |
207 | (address >= MODULES_VADDR && address <= MODULES_END)) { | |
208 | if (!warned) { | |
209 | printk(errata93_warning); | |
210 | warned = 1; | |
211 | } | |
212 | regs->rip = address; | |
213 | return 1; | |
214 | } | |
215 | return 0; | |
216 | } | |
217 | ||
1da177e4 LT |
218 | static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs, |
219 | unsigned long error_code) | |
220 | { | |
1209140c | 221 | unsigned long flags = oops_begin(); |
6e3f3617 | 222 | struct task_struct *tsk; |
1209140c | 223 | |
1da177e4 LT |
224 | printk(KERN_ALERT "%s: Corrupted page table at address %lx\n", |
225 | current->comm, address); | |
226 | dump_pagetable(address); | |
6e3f3617 JB |
227 | tsk = current; |
228 | tsk->thread.cr2 = address; | |
229 | tsk->thread.trap_no = 14; | |
230 | tsk->thread.error_code = error_code; | |
1da177e4 | 231 | __die("Bad pagetable", regs, error_code); |
1209140c | 232 | oops_end(flags); |
1da177e4 LT |
233 | do_exit(SIGKILL); |
234 | } | |
235 | ||
236 | /* | |
f95190b2 | 237 | * Handle a fault on the vmalloc area |
3b9ba4d5 AK |
238 | * |
239 | * This assumes no large pages in there. | |
1da177e4 LT |
240 | */ |
241 | static int vmalloc_fault(unsigned long address) | |
242 | { | |
243 | pgd_t *pgd, *pgd_ref; | |
244 | pud_t *pud, *pud_ref; | |
245 | pmd_t *pmd, *pmd_ref; | |
246 | pte_t *pte, *pte_ref; | |
247 | ||
248 | /* Copy kernel mappings over when needed. This can also | |
249 | happen within a race in page table update. In the later | |
250 | case just flush. */ | |
251 | ||
252 | pgd = pgd_offset(current->mm ?: &init_mm, address); | |
253 | pgd_ref = pgd_offset_k(address); | |
254 | if (pgd_none(*pgd_ref)) | |
255 | return -1; | |
256 | if (pgd_none(*pgd)) | |
257 | set_pgd(pgd, *pgd_ref); | |
8c914cb7 | 258 | else |
46a82b2d | 259 | BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); |
1da177e4 LT |
260 | |
261 | /* Below here mismatches are bugs because these lower tables | |
262 | are shared */ | |
263 | ||
264 | pud = pud_offset(pgd, address); | |
265 | pud_ref = pud_offset(pgd_ref, address); | |
266 | if (pud_none(*pud_ref)) | |
267 | return -1; | |
46a82b2d | 268 | if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref)) |
1da177e4 LT |
269 | BUG(); |
270 | pmd = pmd_offset(pud, address); | |
271 | pmd_ref = pmd_offset(pud_ref, address); | |
272 | if (pmd_none(*pmd_ref)) | |
273 | return -1; | |
274 | if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref)) | |
275 | BUG(); | |
276 | pte_ref = pte_offset_kernel(pmd_ref, address); | |
277 | if (!pte_present(*pte_ref)) | |
278 | return -1; | |
279 | pte = pte_offset_kernel(pmd, address); | |
3b9ba4d5 AK |
280 | /* Don't use pte_page here, because the mappings can point |
281 | outside mem_map, and the NUMA hash lookup cannot handle | |
282 | that. */ | |
283 | if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref)) | |
1da177e4 | 284 | BUG(); |
1da177e4 LT |
285 | return 0; |
286 | } | |
287 | ||
74a1ddc5 | 288 | static int page_fault_trace; |
abd4f750 | 289 | int show_unhandled_signals = 1; |
1da177e4 LT |
290 | |
291 | /* | |
292 | * This routine handles page faults. It determines the address, | |
293 | * and the problem, and then passes it off to one of the appropriate | |
294 | * routines. | |
1da177e4 | 295 | */ |
0f2fbdcb PP |
296 | asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, |
297 | unsigned long error_code) | |
1da177e4 LT |
298 | { |
299 | struct task_struct *tsk; | |
300 | struct mm_struct *mm; | |
301 | struct vm_area_struct * vma; | |
302 | unsigned long address; | |
303 | const struct exception_table_entry *fixup; | |
83c54070 | 304 | int write, fault; |
1209140c | 305 | unsigned long flags; |
1da177e4 LT |
306 | siginfo_t info; |
307 | ||
a9ba9a3b AV |
308 | tsk = current; |
309 | mm = tsk->mm; | |
310 | prefetchw(&mm->mmap_sem); | |
311 | ||
1da177e4 | 312 | /* get the address */ |
f51c9452 | 313 | address = read_cr2(); |
1da177e4 | 314 | |
1da177e4 LT |
315 | info.si_code = SEGV_MAPERR; |
316 | ||
317 | ||
318 | /* | |
319 | * We fault-in kernel-space virtual memory on-demand. The | |
320 | * 'reference' page table is init_mm.pgd. | |
321 | * | |
322 | * NOTE! We MUST NOT take any locks for this case. We may | |
323 | * be in an interrupt or a critical region, and should | |
324 | * only copy the information from the master page table, | |
325 | * nothing more. | |
326 | * | |
327 | * This verifies that the fault happens in kernel space | |
328 | * (error_code & 4) == 0, and that the fault was not a | |
8b1bde93 | 329 | * protection error (error_code & 9) == 0. |
1da177e4 | 330 | */ |
84929801 | 331 | if (unlikely(address >= TASK_SIZE64)) { |
f95190b2 AK |
332 | /* |
333 | * Don't check for the module range here: its PML4 | |
334 | * is always initialized because it's shared with the main | |
335 | * kernel text. Only vmalloc may need PML4 syncups. | |
336 | */ | |
66c58156 | 337 | if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) && |
f95190b2 | 338 | ((address >= VMALLOC_START && address < VMALLOC_END))) { |
8c914cb7 JB |
339 | if (vmalloc_fault(address) >= 0) |
340 | return; | |
1da177e4 | 341 | } |
74a0b576 | 342 | if (notify_page_fault(regs)) |
8c914cb7 | 343 | return; |
1da177e4 LT |
344 | /* |
345 | * Don't take the mm semaphore here. If we fixup a prefetch | |
346 | * fault we could otherwise deadlock. | |
347 | */ | |
348 | goto bad_area_nosemaphore; | |
349 | } | |
350 | ||
74a0b576 | 351 | if (notify_page_fault(regs)) |
8c914cb7 JB |
352 | return; |
353 | ||
354 | if (likely(regs->eflags & X86_EFLAGS_IF)) | |
355 | local_irq_enable(); | |
356 | ||
357 | if (unlikely(page_fault_trace)) | |
358 | printk("pagefault rip:%lx rsp:%lx cs:%lu ss:%lu address %lx error %lx\n", | |
359 | regs->rip,regs->rsp,regs->cs,regs->ss,address,error_code); | |
360 | ||
66c58156 | 361 | if (unlikely(error_code & PF_RSVD)) |
1da177e4 LT |
362 | pgtable_bad(address, regs, error_code); |
363 | ||
364 | /* | |
365 | * If we're in an interrupt or have no user | |
366 | * context, we must not take the fault.. | |
367 | */ | |
368 | if (unlikely(in_atomic() || !mm)) | |
369 | goto bad_area_nosemaphore; | |
370 | ||
dbe3ed1c LT |
371 | /* |
372 | * User-mode registers count as a user access even for any | |
373 | * potential system fault or CPU buglet. | |
374 | */ | |
375 | if (user_mode_vm(regs)) | |
376 | error_code |= PF_USER; | |
377 | ||
1da177e4 LT |
378 | again: |
379 | /* When running in the kernel we expect faults to occur only to | |
380 | * addresses in user space. All other faults represent errors in the | |
381 | * kernel and should generate an OOPS. Unfortunatly, in the case of an | |
80f7228b | 382 | * erroneous fault occurring in a code path which already holds mmap_sem |
1da177e4 LT |
383 | * we will deadlock attempting to validate the fault against the |
384 | * address space. Luckily the kernel only validly references user | |
385 | * space from well defined areas of code, which are listed in the | |
386 | * exceptions table. | |
387 | * | |
388 | * As the vast majority of faults will be valid we will only perform | |
389 | * the source reference check when there is a possibilty of a deadlock. | |
390 | * Attempt to lock the address space, if we cannot we then validate the | |
391 | * source. If this is invalid we can skip the address space check, | |
392 | * thus avoiding the deadlock. | |
393 | */ | |
394 | if (!down_read_trylock(&mm->mmap_sem)) { | |
66c58156 | 395 | if ((error_code & PF_USER) == 0 && |
1da177e4 LT |
396 | !search_exception_tables(regs->rip)) |
397 | goto bad_area_nosemaphore; | |
398 | down_read(&mm->mmap_sem); | |
399 | } | |
400 | ||
401 | vma = find_vma(mm, address); | |
402 | if (!vma) | |
403 | goto bad_area; | |
404 | if (likely(vma->vm_start <= address)) | |
405 | goto good_area; | |
406 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
407 | goto bad_area; | |
408 | if (error_code & 4) { | |
03fdc2c2 CE |
409 | /* Allow userspace just enough access below the stack pointer |
410 | * to let the 'enter' instruction work. | |
411 | */ | |
412 | if (address + 65536 + 32 * sizeof(unsigned long) < regs->rsp) | |
1da177e4 LT |
413 | goto bad_area; |
414 | } | |
415 | if (expand_stack(vma, address)) | |
416 | goto bad_area; | |
417 | /* | |
418 | * Ok, we have a good vm_area for this memory access, so | |
419 | * we can handle it.. | |
420 | */ | |
421 | good_area: | |
422 | info.si_code = SEGV_ACCERR; | |
423 | write = 0; | |
66c58156 | 424 | switch (error_code & (PF_PROT|PF_WRITE)) { |
1da177e4 LT |
425 | default: /* 3: write, present */ |
426 | /* fall through */ | |
66c58156 | 427 | case PF_WRITE: /* write, not present */ |
1da177e4 LT |
428 | if (!(vma->vm_flags & VM_WRITE)) |
429 | goto bad_area; | |
430 | write++; | |
431 | break; | |
66c58156 | 432 | case PF_PROT: /* read, present */ |
1da177e4 | 433 | goto bad_area; |
66c58156 | 434 | case 0: /* read, not present */ |
df67b3da | 435 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
1da177e4 LT |
436 | goto bad_area; |
437 | } | |
438 | ||
439 | /* | |
440 | * If for any reason at all we couldn't handle the fault, | |
441 | * make sure we exit gracefully rather than endlessly redo | |
442 | * the fault. | |
443 | */ | |
83c54070 NP |
444 | fault = handle_mm_fault(mm, vma, address, write); |
445 | if (unlikely(fault & VM_FAULT_ERROR)) { | |
446 | if (fault & VM_FAULT_OOM) | |
447 | goto out_of_memory; | |
448 | else if (fault & VM_FAULT_SIGBUS) | |
449 | goto do_sigbus; | |
450 | BUG(); | |
1da177e4 | 451 | } |
83c54070 NP |
452 | if (fault & VM_FAULT_MAJOR) |
453 | tsk->maj_flt++; | |
454 | else | |
455 | tsk->min_flt++; | |
1da177e4 LT |
456 | up_read(&mm->mmap_sem); |
457 | return; | |
458 | ||
459 | /* | |
460 | * Something tried to access memory that isn't in our memory map.. | |
461 | * Fix it, but check if it's kernel or user first.. | |
462 | */ | |
463 | bad_area: | |
464 | up_read(&mm->mmap_sem); | |
465 | ||
466 | bad_area_nosemaphore: | |
1da177e4 | 467 | /* User mode accesses just cause a SIGSEGV */ |
66c58156 | 468 | if (error_code & PF_USER) { |
e5e3c84b SR |
469 | |
470 | /* | |
471 | * It's possible to have interrupts off here. | |
472 | */ | |
473 | local_irq_enable(); | |
474 | ||
1da177e4 LT |
475 | if (is_prefetch(regs, address, error_code)) |
476 | return; | |
477 | ||
478 | /* Work around K8 erratum #100 K8 in compat mode | |
479 | occasionally jumps to illegal addresses >4GB. We | |
480 | catch this here in the page fault handler because | |
481 | these addresses are not reachable. Just detect this | |
482 | case and return. Any code segment in LDT is | |
483 | compatibility mode. */ | |
484 | if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) && | |
485 | (address >> 32)) | |
486 | return; | |
487 | ||
abd4f750 MAS |
488 | if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && |
489 | printk_ratelimit()) { | |
1da177e4 LT |
490 | printk( |
491 | "%s%s[%d]: segfault at %016lx rip %016lx rsp %016lx error %lx\n", | |
492 | tsk->pid > 1 ? KERN_INFO : KERN_EMERG, | |
493 | tsk->comm, tsk->pid, address, regs->rip, | |
494 | regs->rsp, error_code); | |
495 | } | |
496 | ||
497 | tsk->thread.cr2 = address; | |
498 | /* Kernel addresses are always protection faults */ | |
499 | tsk->thread.error_code = error_code | (address >= TASK_SIZE); | |
500 | tsk->thread.trap_no = 14; | |
501 | info.si_signo = SIGSEGV; | |
502 | info.si_errno = 0; | |
503 | /* info.si_code has been set above */ | |
504 | info.si_addr = (void __user *)address; | |
505 | force_sig_info(SIGSEGV, &info, tsk); | |
506 | return; | |
507 | } | |
508 | ||
509 | no_context: | |
510 | ||
511 | /* Are we prepared to handle this kernel fault? */ | |
512 | fixup = search_exception_tables(regs->rip); | |
513 | if (fixup) { | |
514 | regs->rip = fixup->fixup; | |
515 | return; | |
516 | } | |
517 | ||
518 | /* | |
519 | * Hall of shame of CPU/BIOS bugs. | |
520 | */ | |
521 | ||
522 | if (is_prefetch(regs, address, error_code)) | |
523 | return; | |
524 | ||
525 | if (is_errata93(regs, address)) | |
526 | return; | |
527 | ||
528 | /* | |
529 | * Oops. The kernel tried to access some bad page. We'll have to | |
530 | * terminate things with extreme prejudice. | |
531 | */ | |
532 | ||
1209140c | 533 | flags = oops_begin(); |
1da177e4 LT |
534 | |
535 | if (address < PAGE_SIZE) | |
536 | printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); | |
537 | else | |
538 | printk(KERN_ALERT "Unable to handle kernel paging request"); | |
539 | printk(" at %016lx RIP: \n" KERN_ALERT,address); | |
540 | printk_address(regs->rip); | |
1da177e4 | 541 | dump_pagetable(address); |
6e3f3617 JB |
542 | tsk->thread.cr2 = address; |
543 | tsk->thread.trap_no = 14; | |
544 | tsk->thread.error_code = error_code; | |
1da177e4 LT |
545 | __die("Oops", regs, error_code); |
546 | /* Executive summary in case the body of the oops scrolled away */ | |
547 | printk(KERN_EMERG "CR2: %016lx\n", address); | |
1209140c | 548 | oops_end(flags); |
1da177e4 LT |
549 | do_exit(SIGKILL); |
550 | ||
551 | /* | |
552 | * We ran out of memory, or some other thing happened to us that made | |
553 | * us unable to handle the page fault gracefully. | |
554 | */ | |
555 | out_of_memory: | |
556 | up_read(&mm->mmap_sem); | |
b460cbc5 | 557 | if (is_global_init(current)) { |
1da177e4 LT |
558 | yield(); |
559 | goto again; | |
560 | } | |
561 | printk("VM: killing process %s\n", tsk->comm); | |
562 | if (error_code & 4) | |
021daae2 | 563 | do_group_exit(SIGKILL); |
1da177e4 LT |
564 | goto no_context; |
565 | ||
566 | do_sigbus: | |
567 | up_read(&mm->mmap_sem); | |
568 | ||
569 | /* Kernel mode? Handle exceptions or die */ | |
66c58156 | 570 | if (!(error_code & PF_USER)) |
1da177e4 LT |
571 | goto no_context; |
572 | ||
573 | tsk->thread.cr2 = address; | |
574 | tsk->thread.error_code = error_code; | |
575 | tsk->thread.trap_no = 14; | |
576 | info.si_signo = SIGBUS; | |
577 | info.si_errno = 0; | |
578 | info.si_code = BUS_ADRERR; | |
579 | info.si_addr = (void __user *)address; | |
580 | force_sig_info(SIGBUS, &info, tsk); | |
581 | return; | |
582 | } | |
9e43e1b7 | 583 | |
8c914cb7 | 584 | DEFINE_SPINLOCK(pgd_lock); |
2bff7383 | 585 | LIST_HEAD(pgd_list); |
8c914cb7 JB |
586 | |
587 | void vmalloc_sync_all(void) | |
588 | { | |
589 | /* Note that races in the updates of insync and start aren't | |
590 | problematic: | |
591 | insync can only get set bits added, and updates to start are only | |
592 | improving performance (without affecting correctness if undone). */ | |
593 | static DECLARE_BITMAP(insync, PTRS_PER_PGD); | |
594 | static unsigned long start = VMALLOC_START & PGDIR_MASK; | |
595 | unsigned long address; | |
596 | ||
597 | for (address = start; address <= VMALLOC_END; address += PGDIR_SIZE) { | |
598 | if (!test_bit(pgd_index(address), insync)) { | |
599 | const pgd_t *pgd_ref = pgd_offset_k(address); | |
600 | struct page *page; | |
601 | ||
602 | if (pgd_none(*pgd_ref)) | |
603 | continue; | |
604 | spin_lock(&pgd_lock); | |
2bff7383 | 605 | list_for_each_entry(page, &pgd_list, lru) { |
8c914cb7 JB |
606 | pgd_t *pgd; |
607 | pgd = (pgd_t *)page_address(page) + pgd_index(address); | |
608 | if (pgd_none(*pgd)) | |
609 | set_pgd(pgd, *pgd_ref); | |
610 | else | |
46a82b2d | 611 | BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); |
8c914cb7 JB |
612 | } |
613 | spin_unlock(&pgd_lock); | |
614 | set_bit(pgd_index(address), insync); | |
615 | } | |
616 | if (address == start) | |
617 | start = address + PGDIR_SIZE; | |
618 | } | |
619 | /* Check that there is no need to do the same for the modules area. */ | |
620 | BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); | |
621 | BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == | |
622 | (__START_KERNEL & PGDIR_MASK))); | |
623 | } | |
624 | ||
9e43e1b7 AK |
625 | static int __init enable_pagefaulttrace(char *str) |
626 | { | |
627 | page_fault_trace = 1; | |
9b41046c | 628 | return 1; |
9e43e1b7 AK |
629 | } |
630 | __setup("pagefaulttrace", enable_pagefaulttrace); |