Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/arch/i386/mm/fault.c | |
3 | * | |
4 | * Copyright (C) 1995 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/signal.h> | |
8 | #include <linux/sched.h> | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/errno.h> | |
11 | #include <linux/string.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/ptrace.h> | |
14 | #include <linux/mman.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/smp.h> | |
1da177e4 LT |
17 | #include <linux/interrupt.h> |
18 | #include <linux/init.h> | |
19 | #include <linux/tty.h> | |
20 | #include <linux/vt_kern.h> /* For unblank_screen() */ | |
21 | #include <linux/highmem.h> | |
28609f6e | 22 | #include <linux/bootmem.h> /* for max_low_pfn */ |
1eeb66a1 | 23 | #include <linux/vmalloc.h> |
1da177e4 | 24 | #include <linux/module.h> |
3d97ae5b | 25 | #include <linux/kprobes.h> |
11a4180c | 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 | 31 | #include <asm/desc.h> |
78be3706 | 32 | #include <asm/segment.h> |
1da177e4 LT |
33 | |
34 | extern void die(const char *,struct pt_regs *,long); | |
35 | ||
74a0b576 CH |
36 | #ifdef CONFIG_KPROBES |
37 | static inline int notify_page_fault(struct pt_regs *regs) | |
b71b5b65 | 38 | { |
74a0b576 CH |
39 | int ret = 0; |
40 | ||
41 | /* kprobe_running() needs smp_processor_id() */ | |
42 | if (!user_mode_vm(regs)) { | |
43 | preempt_disable(); | |
44 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) | |
45 | ret = 1; | |
46 | preempt_enable(); | |
47 | } | |
b71b5b65 | 48 | |
74a0b576 | 49 | return ret; |
b71b5b65 | 50 | } |
74a0b576 CH |
51 | #else |
52 | static inline int notify_page_fault(struct pt_regs *regs) | |
b71b5b65 | 53 | { |
74a0b576 | 54 | return 0; |
b71b5b65 | 55 | } |
74a0b576 | 56 | #endif |
b71b5b65 | 57 | |
1da177e4 LT |
58 | /* |
59 | * Return EIP plus the CS segment base. The segment limit is also | |
60 | * adjusted, clamped to the kernel/user address space (whichever is | |
61 | * appropriate), and returned in *eip_limit. | |
62 | * | |
63 | * The segment is checked, because it might have been changed by another | |
64 | * task between the original faulting instruction and here. | |
65 | * | |
66 | * If CS is no longer a valid code segment, or if EIP is beyond the | |
67 | * limit, or if it is a kernel address when CS is not a kernel segment, | |
68 | * then the returned value will be greater than *eip_limit. | |
69 | * | |
70 | * This is slow, but is very rarely executed. | |
71 | */ | |
72 | static inline unsigned long get_segment_eip(struct pt_regs *regs, | |
73 | unsigned long *eip_limit) | |
74 | { | |
65ea5b03 PA |
75 | unsigned long ip = regs->ip; |
76 | unsigned seg = regs->cs & 0xffff; | |
1da177e4 LT |
77 | u32 seg_ar, seg_limit, base, *desc; |
78 | ||
19964fec | 79 | /* Unlikely, but must come before segment checks. */ |
65ea5b03 | 80 | if (unlikely(regs->flags & VM_MASK)) { |
19964fec CE |
81 | base = seg << 4; |
82 | *eip_limit = base + 0xffff; | |
65ea5b03 | 83 | return base + (ip & 0xffff); |
19964fec CE |
84 | } |
85 | ||
1da177e4 | 86 | /* The standard kernel/user address space limit. */ |
78be3706 | 87 | *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg; |
1da177e4 LT |
88 | |
89 | /* By far the most common cases. */ | |
78be3706 | 90 | if (likely(SEGMENT_IS_FLAT_CODE(seg))) |
65ea5b03 | 91 | return ip; |
1da177e4 LT |
92 | |
93 | /* Check the segment exists, is within the current LDT/GDT size, | |
94 | that kernel/user (ring 0..3) has the appropriate privilege, | |
95 | that it's a code segment, and get the limit. */ | |
96 | __asm__ ("larl %3,%0; lsll %3,%1" | |
97 | : "=&r" (seg_ar), "=r" (seg_limit) : "0" (0), "rm" (seg)); | |
65ea5b03 | 98 | if ((~seg_ar & 0x9800) || ip > seg_limit) { |
1da177e4 | 99 | *eip_limit = 0; |
65ea5b03 | 100 | return 1; /* So that returned ip > *eip_limit. */ |
1da177e4 LT |
101 | } |
102 | ||
103 | /* Get the GDT/LDT descriptor base. | |
104 | When you look for races in this code remember that | |
105 | LDT and other horrors are only used in user space. */ | |
106 | if (seg & (1<<2)) { | |
107 | /* Must lock the LDT while reading it. */ | |
de8aacbe | 108 | mutex_lock(¤t->mm->context.lock); |
1da177e4 LT |
109 | desc = current->mm->context.ldt; |
110 | desc = (void *)desc + (seg & ~7); | |
111 | } else { | |
112 | /* Must disable preemption while reading the GDT. */ | |
251e6912 | 113 | desc = (u32 *)get_cpu_gdt_table(get_cpu()); |
1da177e4 LT |
114 | desc = (void *)desc + (seg & ~7); |
115 | } | |
116 | ||
117 | /* Decode the code segment base from the descriptor */ | |
118 | base = get_desc_base((unsigned long *)desc); | |
119 | ||
120 | if (seg & (1<<2)) { | |
de8aacbe | 121 | mutex_unlock(¤t->mm->context.lock); |
1da177e4 LT |
122 | } else |
123 | put_cpu(); | |
124 | ||
125 | /* Adjust EIP and segment limit, and clamp at the kernel limit. | |
126 | It's legitimate for segments to wrap at 0xffffffff. */ | |
127 | seg_limit += base; | |
128 | if (seg_limit < *eip_limit && seg_limit >= base) | |
129 | *eip_limit = seg_limit; | |
65ea5b03 | 130 | return ip + base; |
1da177e4 LT |
131 | } |
132 | ||
133 | /* | |
134 | * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch. | |
135 | * Check that here and ignore it. | |
136 | */ | |
137 | static int __is_prefetch(struct pt_regs *regs, unsigned long addr) | |
138 | { | |
139 | unsigned long limit; | |
11a4180c | 140 | unsigned char *instr = (unsigned char *)get_segment_eip (regs, &limit); |
1da177e4 LT |
141 | int scan_more = 1; |
142 | int prefetch = 0; | |
143 | int i; | |
144 | ||
145 | for (i = 0; scan_more && i < 15; i++) { | |
146 | unsigned char opcode; | |
147 | unsigned char instr_hi; | |
148 | unsigned char instr_lo; | |
149 | ||
11a4180c | 150 | if (instr > (unsigned char *)limit) |
1da177e4 | 151 | break; |
11a4180c | 152 | if (probe_kernel_address(instr, opcode)) |
1da177e4 LT |
153 | break; |
154 | ||
155 | instr_hi = opcode & 0xf0; | |
156 | instr_lo = opcode & 0x0f; | |
157 | instr++; | |
158 | ||
159 | switch (instr_hi) { | |
160 | case 0x20: | |
161 | case 0x30: | |
162 | /* Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes. */ | |
163 | scan_more = ((instr_lo & 7) == 0x6); | |
164 | break; | |
165 | ||
166 | case 0x60: | |
167 | /* 0x64 thru 0x67 are valid prefixes in all modes. */ | |
168 | scan_more = (instr_lo & 0xC) == 0x4; | |
169 | break; | |
170 | case 0xF0: | |
171 | /* 0xF0, 0xF2, and 0xF3 are valid prefixes */ | |
172 | scan_more = !instr_lo || (instr_lo>>1) == 1; | |
173 | break; | |
174 | case 0x00: | |
175 | /* Prefetch instruction is 0x0F0D or 0x0F18 */ | |
176 | scan_more = 0; | |
11a4180c | 177 | if (instr > (unsigned char *)limit) |
1da177e4 | 178 | break; |
11a4180c | 179 | if (probe_kernel_address(instr, opcode)) |
1da177e4 LT |
180 | break; |
181 | prefetch = (instr_lo == 0xF) && | |
182 | (opcode == 0x0D || opcode == 0x18); | |
183 | break; | |
184 | default: | |
185 | scan_more = 0; | |
186 | break; | |
187 | } | |
188 | } | |
189 | return prefetch; | |
190 | } | |
191 | ||
192 | static inline int is_prefetch(struct pt_regs *regs, unsigned long addr, | |
193 | unsigned long error_code) | |
194 | { | |
195 | if (unlikely(boot_cpu_data.x86_vendor == X86_VENDOR_AMD && | |
196 | boot_cpu_data.x86 >= 6)) { | |
197 | /* Catch an obscure case of prefetch inside an NX page. */ | |
198 | if (nx_enabled && (error_code & 16)) | |
199 | return 0; | |
200 | return __is_prefetch(regs, addr); | |
201 | } | |
202 | return 0; | |
203 | } | |
204 | ||
869f96a0 IM |
205 | static noinline void force_sig_info_fault(int si_signo, int si_code, |
206 | unsigned long address, struct task_struct *tsk) | |
207 | { | |
208 | siginfo_t info; | |
209 | ||
210 | info.si_signo = si_signo; | |
211 | info.si_errno = 0; | |
212 | info.si_code = si_code; | |
213 | info.si_addr = (void __user *)address; | |
214 | force_sig_info(si_signo, &info, tsk); | |
215 | } | |
216 | ||
1da177e4 LT |
217 | fastcall void do_invalid_op(struct pt_regs *, unsigned long); |
218 | ||
101f12af JB |
219 | static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address) |
220 | { | |
221 | unsigned index = pgd_index(address); | |
222 | pgd_t *pgd_k; | |
223 | pud_t *pud, *pud_k; | |
224 | pmd_t *pmd, *pmd_k; | |
225 | ||
226 | pgd += index; | |
227 | pgd_k = init_mm.pgd + index; | |
228 | ||
229 | if (!pgd_present(*pgd_k)) | |
230 | return NULL; | |
231 | ||
232 | /* | |
233 | * set_pgd(pgd, *pgd_k); here would be useless on PAE | |
234 | * and redundant with the set_pmd() on non-PAE. As would | |
235 | * set_pud. | |
236 | */ | |
237 | ||
238 | pud = pud_offset(pgd, address); | |
239 | pud_k = pud_offset(pgd_k, address); | |
240 | if (!pud_present(*pud_k)) | |
241 | return NULL; | |
242 | ||
243 | pmd = pmd_offset(pud, address); | |
244 | pmd_k = pmd_offset(pud_k, address); | |
245 | if (!pmd_present(*pmd_k)) | |
246 | return NULL; | |
8b14cb99 | 247 | if (!pmd_present(*pmd)) { |
101f12af | 248 | set_pmd(pmd, *pmd_k); |
8b14cb99 ZA |
249 | arch_flush_lazy_mmu_mode(); |
250 | } else | |
101f12af JB |
251 | BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k)); |
252 | return pmd_k; | |
253 | } | |
254 | ||
255 | /* | |
256 | * Handle a fault on the vmalloc or module mapping area | |
257 | * | |
258 | * This assumes no large pages in there. | |
259 | */ | |
260 | static inline int vmalloc_fault(unsigned long address) | |
261 | { | |
262 | unsigned long pgd_paddr; | |
263 | pmd_t *pmd_k; | |
264 | pte_t *pte_k; | |
265 | /* | |
266 | * Synchronize this task's top level page-table | |
267 | * with the 'reference' page table. | |
268 | * | |
269 | * Do _not_ use "current" here. We might be inside | |
270 | * an interrupt in the middle of a task switch.. | |
271 | */ | |
272 | pgd_paddr = read_cr3(); | |
273 | pmd_k = vmalloc_sync_one(__va(pgd_paddr), address); | |
274 | if (!pmd_k) | |
275 | return -1; | |
276 | pte_k = pte_offset_kernel(pmd_k, address); | |
277 | if (!pte_present(*pte_k)) | |
278 | return -1; | |
279 | return 0; | |
280 | } | |
281 | ||
abd4f750 MAS |
282 | int show_unhandled_signals = 1; |
283 | ||
1da177e4 LT |
284 | /* |
285 | * This routine handles page faults. It determines the address, | |
286 | * and the problem, and then passes it off to one of the appropriate | |
287 | * routines. | |
288 | * | |
289 | * error_code: | |
290 | * bit 0 == 0 means no page found, 1 means protection fault | |
291 | * bit 1 == 0 means read, 1 means write | |
292 | * bit 2 == 0 means kernel, 1 means user-mode | |
101f12af JB |
293 | * bit 3 == 1 means use of reserved bit detected |
294 | * bit 4 == 1 means fault was an instruction fetch | |
1da177e4 | 295 | */ |
3d97ae5b PP |
296 | fastcall 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; | |
869f96a0 | 303 | int write, si_code; |
83c54070 | 304 | int fault; |
1da177e4 | 305 | |
143a5d32 PZ |
306 | /* |
307 | * We can fault from pretty much anywhere, with unknown IRQ state. | |
308 | */ | |
309 | trace_hardirqs_fixup(); | |
310 | ||
1da177e4 | 311 | /* get the address */ |
4bb0d3ec | 312 | address = read_cr2(); |
1da177e4 | 313 | |
1da177e4 LT |
314 | tsk = current; |
315 | ||
869f96a0 | 316 | si_code = SEGV_MAPERR; |
1da177e4 LT |
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 | |
101f12af | 329 | * protection error (error_code & 9) == 0. |
1da177e4 | 330 | */ |
101f12af JB |
331 | if (unlikely(address >= TASK_SIZE)) { |
332 | if (!(error_code & 0x0000000d) && vmalloc_fault(address) >= 0) | |
333 | return; | |
74a0b576 | 334 | if (notify_page_fault(regs)) |
101f12af JB |
335 | return; |
336 | /* | |
1da177e4 LT |
337 | * Don't take the mm semaphore here. If we fixup a prefetch |
338 | * fault we could otherwise deadlock. | |
339 | */ | |
340 | goto bad_area_nosemaphore; | |
101f12af JB |
341 | } |
342 | ||
74a0b576 | 343 | if (notify_page_fault(regs)) |
101f12af JB |
344 | return; |
345 | ||
346 | /* It's safe to allow irq's after cr2 has been saved and the vmalloc | |
347 | fault has been handled. */ | |
65ea5b03 | 348 | if (regs->flags & (X86_EFLAGS_IF|VM_MASK)) |
101f12af | 349 | local_irq_enable(); |
1da177e4 LT |
350 | |
351 | mm = tsk->mm; | |
352 | ||
353 | /* | |
354 | * If we're in an interrupt, have no user context or are running in an | |
355 | * atomic region then we must not take the fault.. | |
356 | */ | |
357 | if (in_atomic() || !mm) | |
358 | goto bad_area_nosemaphore; | |
359 | ||
360 | /* When running in the kernel we expect faults to occur only to | |
361 | * addresses in user space. All other faults represent errors in the | |
27b46d76 | 362 | * kernel and should generate an OOPS. Unfortunately, in the case of an |
80f7228b | 363 | * erroneous fault occurring in a code path which already holds mmap_sem |
1da177e4 LT |
364 | * we will deadlock attempting to validate the fault against the |
365 | * address space. Luckily the kernel only validly references user | |
366 | * space from well defined areas of code, which are listed in the | |
367 | * exceptions table. | |
368 | * | |
369 | * As the vast majority of faults will be valid we will only perform | |
27b46d76 | 370 | * the source reference check when there is a possibility of a deadlock. |
1da177e4 LT |
371 | * Attempt to lock the address space, if we cannot we then validate the |
372 | * source. If this is invalid we can skip the address space check, | |
373 | * thus avoiding the deadlock. | |
374 | */ | |
375 | if (!down_read_trylock(&mm->mmap_sem)) { | |
376 | if ((error_code & 4) == 0 && | |
65ea5b03 | 377 | !search_exception_tables(regs->ip)) |
1da177e4 LT |
378 | goto bad_area_nosemaphore; |
379 | down_read(&mm->mmap_sem); | |
380 | } | |
381 | ||
382 | vma = find_vma(mm, address); | |
383 | if (!vma) | |
384 | goto bad_area; | |
385 | if (vma->vm_start <= address) | |
386 | goto good_area; | |
387 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
388 | goto bad_area; | |
389 | if (error_code & 4) { | |
390 | /* | |
65ea5b03 | 391 | * Accessing the stack below %sp is always a bug. |
21528454 CE |
392 | * The large cushion allows instructions like enter |
393 | * and pusha to work. ("enter $65535,$31" pushes | |
65ea5b03 | 394 | * 32 pointers and then decrements %sp by 65535.) |
1da177e4 | 395 | */ |
65ea5b03 | 396 | if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp) |
1da177e4 LT |
397 | goto bad_area; |
398 | } | |
399 | if (expand_stack(vma, address)) | |
400 | goto bad_area; | |
401 | /* | |
402 | * Ok, we have a good vm_area for this memory access, so | |
403 | * we can handle it.. | |
404 | */ | |
405 | good_area: | |
869f96a0 | 406 | si_code = SEGV_ACCERR; |
1da177e4 LT |
407 | write = 0; |
408 | switch (error_code & 3) { | |
409 | default: /* 3: write, present */ | |
78be3706 | 410 | /* fall through */ |
1da177e4 LT |
411 | case 2: /* write, not present */ |
412 | if (!(vma->vm_flags & VM_WRITE)) | |
413 | goto bad_area; | |
414 | write++; | |
415 | break; | |
416 | case 1: /* read, present */ | |
417 | goto bad_area; | |
418 | case 0: /* read, not present */ | |
df67b3da | 419 | if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) |
1da177e4 LT |
420 | goto bad_area; |
421 | } | |
422 | ||
423 | survive: | |
424 | /* | |
425 | * If for any reason at all we couldn't handle the fault, | |
426 | * make sure we exit gracefully rather than endlessly redo | |
427 | * the fault. | |
428 | */ | |
83c54070 NP |
429 | fault = handle_mm_fault(mm, vma, address, write); |
430 | if (unlikely(fault & VM_FAULT_ERROR)) { | |
431 | if (fault & VM_FAULT_OOM) | |
1da177e4 | 432 | goto out_of_memory; |
83c54070 NP |
433 | else if (fault & VM_FAULT_SIGBUS) |
434 | goto do_sigbus; | |
435 | BUG(); | |
1da177e4 | 436 | } |
83c54070 NP |
437 | if (fault & VM_FAULT_MAJOR) |
438 | tsk->maj_flt++; | |
439 | else | |
440 | tsk->min_flt++; | |
1da177e4 LT |
441 | |
442 | /* | |
443 | * Did it hit the DOS screen memory VA from vm86 mode? | |
444 | */ | |
65ea5b03 | 445 | if (regs->flags & VM_MASK) { |
1da177e4 LT |
446 | unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT; |
447 | if (bit < 32) | |
448 | tsk->thread.screen_bitmap |= 1 << bit; | |
449 | } | |
450 | up_read(&mm->mmap_sem); | |
451 | return; | |
452 | ||
453 | /* | |
454 | * Something tried to access memory that isn't in our memory map.. | |
455 | * Fix it, but check if it's kernel or user first.. | |
456 | */ | |
457 | bad_area: | |
458 | up_read(&mm->mmap_sem); | |
459 | ||
460 | bad_area_nosemaphore: | |
461 | /* User mode accesses just cause a SIGSEGV */ | |
462 | if (error_code & 4) { | |
e5e3c84b SR |
463 | /* |
464 | * It's possible to have interrupts off here. | |
465 | */ | |
466 | local_irq_enable(); | |
467 | ||
1da177e4 LT |
468 | /* |
469 | * Valid to do another page fault here because this one came | |
470 | * from user space. | |
471 | */ | |
472 | if (is_prefetch(regs, address, error_code)) | |
473 | return; | |
474 | ||
abd4f750 MAS |
475 | if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && |
476 | printk_ratelimit()) { | |
65ea5b03 PA |
477 | printk("%s%s[%d]: segfault at %08lx ip %08lx " |
478 | "sp %08lx error %lx\n", | |
19c5870c | 479 | task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, |
65ea5b03 PA |
480 | tsk->comm, task_pid_nr(tsk), address, regs->ip, |
481 | regs->sp, error_code); | |
abd4f750 | 482 | } |
1da177e4 LT |
483 | tsk->thread.cr2 = address; |
484 | /* Kernel addresses are always protection faults */ | |
485 | tsk->thread.error_code = error_code | (address >= TASK_SIZE); | |
486 | tsk->thread.trap_no = 14; | |
869f96a0 | 487 | force_sig_info_fault(SIGSEGV, si_code, address, tsk); |
1da177e4 LT |
488 | return; |
489 | } | |
490 | ||
491 | #ifdef CONFIG_X86_F00F_BUG | |
492 | /* | |
493 | * Pentium F0 0F C7 C8 bug workaround. | |
494 | */ | |
495 | if (boot_cpu_data.f00f_bug) { | |
496 | unsigned long nr; | |
497 | ||
498 | nr = (address - idt_descr.address) >> 3; | |
499 | ||
500 | if (nr == 6) { | |
501 | do_invalid_op(regs, 0); | |
502 | return; | |
503 | } | |
504 | } | |
505 | #endif | |
506 | ||
507 | no_context: | |
508 | /* Are we prepared to handle this kernel fault? */ | |
509 | if (fixup_exception(regs)) | |
510 | return; | |
511 | ||
512 | /* | |
513 | * Valid to do another page fault here, because if this fault | |
514 | * had been triggered by is_prefetch fixup_exception would have | |
515 | * handled it. | |
516 | */ | |
517 | if (is_prefetch(regs, address, error_code)) | |
518 | return; | |
519 | ||
520 | /* | |
521 | * Oops. The kernel tried to access some bad page. We'll have to | |
522 | * terminate things with extreme prejudice. | |
523 | */ | |
524 | ||
525 | bust_spinlocks(1); | |
526 | ||
dd287796 | 527 | if (oops_may_print()) { |
28609f6e JB |
528 | __typeof__(pte_val(__pte(0))) page; |
529 | ||
530 | #ifdef CONFIG_X86_PAE | |
dd287796 AM |
531 | if (error_code & 16) { |
532 | pte_t *pte = lookup_address(address); | |
533 | ||
534 | if (pte && pte_present(*pte) && !pte_exec_kernel(*pte)) | |
535 | printk(KERN_CRIT "kernel tried to execute " | |
536 | "NX-protected page - exploit attempt? " | |
537 | "(uid: %d)\n", current->uid); | |
538 | } | |
28609f6e | 539 | #endif |
dd287796 AM |
540 | if (address < PAGE_SIZE) |
541 | printk(KERN_ALERT "BUG: unable to handle kernel NULL " | |
542 | "pointer dereference"); | |
543 | else | |
544 | printk(KERN_ALERT "BUG: unable to handle kernel paging" | |
545 | " request"); | |
546 | printk(" at virtual address %08lx\n",address); | |
65ea5b03 | 547 | printk(KERN_ALERT "printing ip: %08lx ", regs->ip); |
28609f6e JB |
548 | |
549 | page = read_cr3(); | |
550 | page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT]; | |
551 | #ifdef CONFIG_X86_PAE | |
9aa8d719 | 552 | printk("*pdpt = %016Lx ", page); |
28609f6e JB |
553 | if ((page >> PAGE_SHIFT) < max_low_pfn |
554 | && page & _PAGE_PRESENT) { | |
555 | page &= PAGE_MASK; | |
556 | page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT) | |
557 | & (PTRS_PER_PMD - 1)]; | |
eec407c9 | 558 | printk(KERN_CONT "*pde = %016Lx ", page); |
28609f6e JB |
559 | page &= ~_PAGE_NX; |
560 | } | |
561 | #else | |
9aa8d719 | 562 | printk("*pde = %08lx ", page); |
1da177e4 | 563 | #endif |
28609f6e JB |
564 | |
565 | /* | |
566 | * We must not directly access the pte in the highpte | |
567 | * case if the page table is located in highmem. | |
568 | * And let's rather not kmap-atomic the pte, just in case | |
569 | * it's allocated already. | |
570 | */ | |
571 | if ((page >> PAGE_SHIFT) < max_low_pfn | |
b1992df3 JB |
572 | && (page & _PAGE_PRESENT) |
573 | && !(page & _PAGE_PSE)) { | |
28609f6e JB |
574 | page &= PAGE_MASK; |
575 | page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT) | |
576 | & (PTRS_PER_PTE - 1)]; | |
9aa8d719 | 577 | printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page); |
28609f6e | 578 | } |
9aa8d719 PE |
579 | |
580 | printk("\n"); | |
28609f6e JB |
581 | } |
582 | ||
4f339ecb AN |
583 | tsk->thread.cr2 = address; |
584 | tsk->thread.trap_no = 14; | |
585 | tsk->thread.error_code = error_code; | |
1da177e4 LT |
586 | die("Oops", regs, error_code); |
587 | bust_spinlocks(0); | |
588 | do_exit(SIGKILL); | |
589 | ||
590 | /* | |
591 | * We ran out of memory, or some other thing happened to us that made | |
592 | * us unable to handle the page fault gracefully. | |
593 | */ | |
594 | out_of_memory: | |
595 | up_read(&mm->mmap_sem); | |
b460cbc5 | 596 | if (is_global_init(tsk)) { |
1da177e4 LT |
597 | yield(); |
598 | down_read(&mm->mmap_sem); | |
599 | goto survive; | |
600 | } | |
601 | printk("VM: killing process %s\n", tsk->comm); | |
602 | if (error_code & 4) | |
dcca2bde | 603 | do_group_exit(SIGKILL); |
1da177e4 LT |
604 | goto no_context; |
605 | ||
606 | do_sigbus: | |
607 | up_read(&mm->mmap_sem); | |
608 | ||
609 | /* Kernel mode? Handle exceptions or die */ | |
610 | if (!(error_code & 4)) | |
611 | goto no_context; | |
612 | ||
613 | /* User space => ok to do another page fault */ | |
614 | if (is_prefetch(regs, address, error_code)) | |
615 | return; | |
616 | ||
617 | tsk->thread.cr2 = address; | |
618 | tsk->thread.error_code = error_code; | |
619 | tsk->thread.trap_no = 14; | |
869f96a0 | 620 | force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk); |
101f12af | 621 | } |
1da177e4 | 622 | |
101f12af JB |
623 | void vmalloc_sync_all(void) |
624 | { | |
625 | /* | |
626 | * Note that races in the updates of insync and start aren't | |
627 | * problematic: insync can only get set bits added, and updates to | |
628 | * start are only improving performance (without affecting correctness | |
629 | * if undone). | |
630 | */ | |
631 | static DECLARE_BITMAP(insync, PTRS_PER_PGD); | |
632 | static unsigned long start = TASK_SIZE; | |
633 | unsigned long address; | |
1da177e4 | 634 | |
5311ab62 JF |
635 | if (SHARED_KERNEL_PMD) |
636 | return; | |
637 | ||
101f12af JB |
638 | BUILD_BUG_ON(TASK_SIZE & ~PGDIR_MASK); |
639 | for (address = start; address >= TASK_SIZE; address += PGDIR_SIZE) { | |
640 | if (!test_bit(pgd_index(address), insync)) { | |
641 | unsigned long flags; | |
642 | struct page *page; | |
643 | ||
644 | spin_lock_irqsave(&pgd_lock, flags); | |
645 | for (page = pgd_list; page; page = | |
646 | (struct page *)page->index) | |
647 | if (!vmalloc_sync_one(page_address(page), | |
648 | address)) { | |
649 | BUG_ON(page != pgd_list); | |
650 | break; | |
651 | } | |
652 | spin_unlock_irqrestore(&pgd_lock, flags); | |
653 | if (!page) | |
654 | set_bit(pgd_index(address), insync); | |
655 | } | |
656 | if (address == start && test_bit(pgd_index(address), insync)) | |
657 | start = address + PGDIR_SIZE; | |
1da177e4 LT |
658 | } |
659 | } |