2 * Copyright (C) 1995 Linus Torvalds
3 * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
6 #include <linux/signal.h>
7 #include <linux/sched.h>
8 #include <linux/kernel.h>
9 #include <linux/errno.h>
10 #include <linux/string.h>
11 #include <linux/types.h>
12 #include <linux/ptrace.h>
13 #include <linux/mmiotrace.h>
14 #include <linux/mman.h>
16 #include <linux/smp.h>
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/compiler.h>
22 #include <linux/highmem.h>
23 #include <linux/bootmem.h> /* for max_low_pfn */
24 #include <linux/vmalloc.h>
25 #include <linux/module.h>
26 #include <linux/kprobes.h>
27 #include <linux/uaccess.h>
28 #include <linux/kdebug.h>
30 #include <asm/system.h>
32 #include <asm/segment.h>
33 #include <asm/pgalloc.h>
35 #include <asm/tlbflush.h>
36 #include <asm/proto.h>
37 #include <asm-generic/sections.h>
38 #include <asm/traps.h>
41 * Page fault error code bits
42 * bit 0 == 0 means no page found, 1 means protection fault
43 * bit 1 == 0 means read, 1 means write
44 * bit 2 == 0 means kernel, 1 means user-mode
45 * bit 3 == 1 means use of reserved bit detected
46 * bit 4 == 1 means fault was an instruction fetch
48 #define PF_PROT (1<<0)
49 #define PF_WRITE (1<<1)
50 #define PF_USER (1<<2)
51 #define PF_RSVD (1<<3)
52 #define PF_INSTR (1<<4)
54 static inline int kmmio_fault(struct pt_regs
*regs
, unsigned long addr
)
56 #ifdef CONFIG_MMIOTRACE_HOOKS
57 if (unlikely(is_kmmio_active()))
58 if (kmmio_handler(regs
, addr
) == 1)
64 static inline int notify_page_fault(struct pt_regs
*regs
)
69 /* kprobe_running() needs smp_processor_id() */
70 if (!user_mode_vm(regs
)) {
72 if (kprobe_running() && kprobe_fault_handler(regs
, 14))
85 * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
86 * Check that here and ignore it.
89 * Sometimes the CPU reports invalid exceptions on prefetch.
90 * Check that here and ignore it.
92 * Opcode checker based on code by Richard Brunner
94 static int is_prefetch(struct pt_regs
*regs
, unsigned long addr
,
95 unsigned long error_code
)
100 unsigned char *max_instr
;
103 * If it was a exec (instruction fetch) fault on NX page, then
104 * do not ignore the fault:
106 if (error_code
& PF_INSTR
)
109 instr
= (unsigned char *)convert_ip_to_linear(current
, regs
);
110 max_instr
= instr
+ 15;
112 if (user_mode(regs
) && instr
>= (unsigned char *)TASK_SIZE
)
115 while (scan_more
&& instr
< max_instr
) {
116 unsigned char opcode
;
117 unsigned char instr_hi
;
118 unsigned char instr_lo
;
120 if (probe_kernel_address(instr
, opcode
))
123 instr_hi
= opcode
& 0xf0;
124 instr_lo
= opcode
& 0x0f;
131 * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
132 * In X86_64 long mode, the CPU will signal invalid
133 * opcode if some of these prefixes are present so
134 * X86_64 will never get here anyway
136 scan_more
= ((instr_lo
& 7) == 0x6);
141 * In AMD64 long mode 0x40..0x4F are valid REX prefixes
142 * Need to figure out under what instruction mode the
143 * instruction was issued. Could check the LDT for lm,
144 * but for now it's good enough to assume that long
145 * mode only uses well known segments or kernel.
147 scan_more
= (!user_mode(regs
)) || (regs
->cs
== __USER_CS
);
151 /* 0x64 thru 0x67 are valid prefixes in all modes. */
152 scan_more
= (instr_lo
& 0xC) == 0x4;
155 /* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */
156 scan_more
= !instr_lo
|| (instr_lo
>>1) == 1;
159 /* Prefetch instruction is 0x0F0D or 0x0F18 */
162 if (probe_kernel_address(instr
, opcode
))
164 prefetch
= (instr_lo
== 0xF) &&
165 (opcode
== 0x0D || opcode
== 0x18);
175 static void force_sig_info_fault(int si_signo
, int si_code
,
176 unsigned long address
, struct task_struct
*tsk
)
180 info
.si_signo
= si_signo
;
182 info
.si_code
= si_code
;
183 info
.si_addr
= (void __user
*)address
;
184 force_sig_info(si_signo
, &info
, tsk
);
188 static int bad_address(void *p
)
191 return probe_kernel_address((unsigned long *)p
, dummy
);
195 static void dump_pagetable(unsigned long address
)
198 __typeof__(pte_val(__pte(0))) page
;
201 page
= ((__typeof__(page
) *) __va(page
))[address
>> PGDIR_SHIFT
];
202 #ifdef CONFIG_X86_PAE
203 printk("*pdpt = %016Lx ", page
);
204 if ((page
>> PAGE_SHIFT
) < max_low_pfn
205 && page
& _PAGE_PRESENT
) {
207 page
= ((__typeof__(page
) *) __va(page
))[(address
>> PMD_SHIFT
)
208 & (PTRS_PER_PMD
- 1)];
209 printk(KERN_CONT
"*pde = %016Lx ", page
);
213 printk("*pde = %08lx ", page
);
217 * We must not directly access the pte in the highpte
218 * case if the page table is located in highmem.
219 * And let's rather not kmap-atomic the pte, just in case
220 * it's allocated already.
222 if ((page
>> PAGE_SHIFT
) < max_low_pfn
223 && (page
& _PAGE_PRESENT
)
224 && !(page
& _PAGE_PSE
)) {
226 page
= ((__typeof__(page
) *) __va(page
))[(address
>> PAGE_SHIFT
)
227 & (PTRS_PER_PTE
- 1)];
228 printk("*pte = %0*Lx ", sizeof(page
)*2, (u64
)page
);
232 #else /* CONFIG_X86_64 */
238 pgd
= (pgd_t
*)read_cr3();
240 pgd
= __va((unsigned long)pgd
& PHYSICAL_PAGE_MASK
);
241 pgd
+= pgd_index(address
);
242 if (bad_address(pgd
)) goto bad
;
243 printk("PGD %lx ", pgd_val(*pgd
));
244 if (!pgd_present(*pgd
)) goto ret
;
246 pud
= pud_offset(pgd
, address
);
247 if (bad_address(pud
)) goto bad
;
248 printk("PUD %lx ", pud_val(*pud
));
249 if (!pud_present(*pud
) || pud_large(*pud
))
252 pmd
= pmd_offset(pud
, address
);
253 if (bad_address(pmd
)) goto bad
;
254 printk("PMD %lx ", pmd_val(*pmd
));
255 if (!pmd_present(*pmd
) || pmd_large(*pmd
)) goto ret
;
257 pte
= pte_offset_kernel(pmd
, address
);
258 if (bad_address(pte
)) goto bad
;
259 printk("PTE %lx", pte_val(*pte
));
269 static inline pmd_t
*vmalloc_sync_one(pgd_t
*pgd
, unsigned long address
)
271 unsigned index
= pgd_index(address
);
277 pgd_k
= init_mm
.pgd
+ index
;
279 if (!pgd_present(*pgd_k
))
283 * set_pgd(pgd, *pgd_k); here would be useless on PAE
284 * and redundant with the set_pmd() on non-PAE. As would
288 pud
= pud_offset(pgd
, address
);
289 pud_k
= pud_offset(pgd_k
, address
);
290 if (!pud_present(*pud_k
))
293 pmd
= pmd_offset(pud
, address
);
294 pmd_k
= pmd_offset(pud_k
, address
);
295 if (!pmd_present(*pmd_k
))
297 if (!pmd_present(*pmd
)) {
298 set_pmd(pmd
, *pmd_k
);
299 arch_flush_lazy_mmu_mode();
301 BUG_ON(pmd_page(*pmd
) != pmd_page(*pmd_k
));
307 static const char errata93_warning
[] =
308 KERN_ERR
"******* Your BIOS seems to not contain a fix for K8 errata #93\n"
309 KERN_ERR
"******* Working around it, but it may cause SEGVs or burn power.\n"
310 KERN_ERR
"******* Please consider a BIOS update.\n"
311 KERN_ERR
"******* Disabling USB legacy in the BIOS may also help.\n";
314 /* Workaround for K8 erratum #93 & buggy BIOS.
315 BIOS SMM functions are required to use a specific workaround
316 to avoid corruption of the 64bit RIP register on C stepping K8.
317 A lot of BIOS that didn't get tested properly miss this.
318 The OS sees this as a page fault with the upper 32bits of RIP cleared.
319 Try to work around it here.
320 Note we only handle faults in kernel here.
321 Does nothing for X86_32
323 static int is_errata93(struct pt_regs
*regs
, unsigned long address
)
327 if (address
!= regs
->ip
)
329 if ((address
>> 32) != 0)
331 address
|= 0xffffffffUL
<< 32;
332 if ((address
>= (u64
)_stext
&& address
<= (u64
)_etext
) ||
333 (address
>= MODULES_VADDR
&& address
<= MODULES_END
)) {
335 printk(errata93_warning
);
346 * Work around K8 erratum #100 K8 in compat mode occasionally jumps to illegal
347 * addresses >4GB. We catch this in the page fault handler because these
348 * addresses are not reachable. Just detect this case and return. Any code
349 * segment in LDT is compatibility mode.
351 static int is_errata100(struct pt_regs
*regs
, unsigned long address
)
354 if ((regs
->cs
== __USER32_CS
|| (regs
->cs
& (1<<2))) &&
361 static int is_f00f_bug(struct pt_regs
*regs
, unsigned long address
)
363 #ifdef CONFIG_X86_F00F_BUG
366 * Pentium F0 0F C7 C8 bug workaround.
368 if (boot_cpu_data
.f00f_bug
) {
369 nr
= (address
- idt_descr
.address
) >> 3;
372 do_invalid_op(regs
, 0);
380 static void show_fault_oops(struct pt_regs
*regs
, unsigned long error_code
,
381 unsigned long address
)
384 if (!oops_may_print())
388 #ifdef CONFIG_X86_PAE
389 if (error_code
& PF_INSTR
) {
391 pte_t
*pte
= lookup_address(address
, &level
);
393 if (pte
&& pte_present(*pte
) && !pte_exec(*pte
))
394 printk(KERN_CRIT
"kernel tried to execute "
395 "NX-protected page - exploit attempt? "
396 "(uid: %d)\n", current_uid());
400 printk(KERN_ALERT
"BUG: unable to handle kernel ");
401 if (address
< PAGE_SIZE
)
402 printk(KERN_CONT
"NULL pointer dereference");
404 printk(KERN_CONT
"paging request");
405 printk(KERN_CONT
" at %p\n", (void *) address
);
406 printk(KERN_ALERT
"IP:");
407 printk_address(regs
->ip
, 1);
408 dump_pagetable(address
);
412 static noinline
void pgtable_bad(unsigned long address
, struct pt_regs
*regs
,
413 unsigned long error_code
)
415 unsigned long flags
= oops_begin();
417 struct task_struct
*tsk
;
419 printk(KERN_ALERT
"%s: Corrupted page table at address %lx\n",
420 current
->comm
, address
);
421 dump_pagetable(address
);
423 tsk
->thread
.cr2
= address
;
424 tsk
->thread
.trap_no
= 14;
425 tsk
->thread
.error_code
= error_code
;
426 if (__die("Bad pagetable", regs
, error_code
))
428 oops_end(flags
, regs
, sig
);
432 static int spurious_fault_check(unsigned long error_code
, pte_t
*pte
)
434 if ((error_code
& PF_WRITE
) && !pte_write(*pte
))
436 if ((error_code
& PF_INSTR
) && !pte_exec(*pte
))
443 * Handle a spurious fault caused by a stale TLB entry. This allows
444 * us to lazily refresh the TLB when increasing the permissions of a
445 * kernel page (RO -> RW or NX -> X). Doing it eagerly is very
446 * expensive since that implies doing a full cross-processor TLB
447 * flush, even if no stale TLB entries exist on other processors.
448 * There are no security implications to leaving a stale TLB when
449 * increasing the permissions on a page.
451 static int spurious_fault(unsigned long address
,
452 unsigned long error_code
)
459 /* Reserved-bit violation or user access to kernel space? */
460 if (error_code
& (PF_USER
| PF_RSVD
))
463 pgd
= init_mm
.pgd
+ pgd_index(address
);
464 if (!pgd_present(*pgd
))
467 pud
= pud_offset(pgd
, address
);
468 if (!pud_present(*pud
))
472 return spurious_fault_check(error_code
, (pte_t
*) pud
);
474 pmd
= pmd_offset(pud
, address
);
475 if (!pmd_present(*pmd
))
479 return spurious_fault_check(error_code
, (pte_t
*) pmd
);
481 pte
= pte_offset_kernel(pmd
, address
);
482 if (!pte_present(*pte
))
485 return spurious_fault_check(error_code
, pte
);
490 * Handle a fault on the vmalloc or module mapping area
493 * Handle a fault on the vmalloc area
495 * This assumes no large pages in there.
497 static int vmalloc_fault(unsigned long address
)
500 unsigned long pgd_paddr
;
504 /* Make sure we are in vmalloc area */
505 if (!(address
>= VMALLOC_START
&& address
< VMALLOC_END
))
509 * Synchronize this task's top level page-table
510 * with the 'reference' page table.
512 * Do _not_ use "current" here. We might be inside
513 * an interrupt in the middle of a task switch..
515 pgd_paddr
= read_cr3();
516 pmd_k
= vmalloc_sync_one(__va(pgd_paddr
), address
);
519 pte_k
= pte_offset_kernel(pmd_k
, address
);
520 if (!pte_present(*pte_k
))
524 pgd_t
*pgd
, *pgd_ref
;
525 pud_t
*pud
, *pud_ref
;
526 pmd_t
*pmd
, *pmd_ref
;
527 pte_t
*pte
, *pte_ref
;
529 /* Make sure we are in vmalloc area */
530 if (!(address
>= VMALLOC_START
&& address
< VMALLOC_END
))
533 /* Copy kernel mappings over when needed. This can also
534 happen within a race in page table update. In the later
537 pgd
= pgd_offset(current
->mm
?: &init_mm
, address
);
538 pgd_ref
= pgd_offset_k(address
);
539 if (pgd_none(*pgd_ref
))
542 set_pgd(pgd
, *pgd_ref
);
544 BUG_ON(pgd_page_vaddr(*pgd
) != pgd_page_vaddr(*pgd_ref
));
546 /* Below here mismatches are bugs because these lower tables
549 pud
= pud_offset(pgd
, address
);
550 pud_ref
= pud_offset(pgd_ref
, address
);
551 if (pud_none(*pud_ref
))
553 if (pud_none(*pud
) || pud_page_vaddr(*pud
) != pud_page_vaddr(*pud_ref
))
555 pmd
= pmd_offset(pud
, address
);
556 pmd_ref
= pmd_offset(pud_ref
, address
);
557 if (pmd_none(*pmd_ref
))
559 if (pmd_none(*pmd
) || pmd_page(*pmd
) != pmd_page(*pmd_ref
))
561 pte_ref
= pte_offset_kernel(pmd_ref
, address
);
562 if (!pte_present(*pte_ref
))
564 pte
= pte_offset_kernel(pmd
, address
);
565 /* Don't use pte_page here, because the mappings can point
566 outside mem_map, and the NUMA hash lookup cannot handle
568 if (!pte_present(*pte
) || pte_pfn(*pte
) != pte_pfn(*pte_ref
))
574 int show_unhandled_signals
= 1;
577 * This routine handles page faults. It determines the address,
578 * and the problem, and then passes it off to one of the appropriate
584 void __kprobes
do_page_fault(struct pt_regs
*regs
, unsigned long error_code
)
586 struct task_struct
*tsk
;
587 struct mm_struct
*mm
;
588 struct vm_area_struct
*vma
;
589 unsigned long address
;
599 prefetchw(&mm
->mmap_sem
);
601 /* get the address */
602 address
= read_cr2();
604 si_code
= SEGV_MAPERR
;
606 if (notify_page_fault(regs
))
608 if (unlikely(kmmio_fault(regs
, address
)))
612 * We fault-in kernel-space virtual memory on-demand. The
613 * 'reference' page table is init_mm.pgd.
615 * NOTE! We MUST NOT take any locks for this case. We may
616 * be in an interrupt or a critical region, and should
617 * only copy the information from the master page table,
620 * This verifies that the fault happens in kernel space
621 * (error_code & 4) == 0, and that the fault was not a
622 * protection error (error_code & 9) == 0.
625 if (unlikely(address
>= TASK_SIZE
)) {
627 if (unlikely(address
>= TASK_SIZE64
)) {
629 if (!(error_code
& (PF_RSVD
|PF_USER
|PF_PROT
)) &&
630 vmalloc_fault(address
) >= 0)
633 /* Can handle a stale RO->RW TLB */
634 if (spurious_fault(address
, error_code
))
638 * Don't take the mm semaphore here. If we fixup a prefetch
639 * fault we could otherwise deadlock.
641 goto bad_area_nosemaphore
;
646 * It's safe to allow irq's after cr2 has been saved and the
647 * vmalloc fault has been handled.
649 * User-mode registers count as a user access even for any
650 * potential system fault or CPU buglet.
652 if (user_mode_vm(regs
)) {
654 error_code
|= PF_USER
;
655 } else if (regs
->flags
& X86_EFLAGS_IF
)
659 if (unlikely(error_code
& PF_RSVD
))
660 pgtable_bad(address
, regs
, error_code
);
664 * If we're in an interrupt, have no user context or are running in an
665 * atomic region then we must not take the fault.
667 if (unlikely(in_atomic() || !mm
))
668 goto bad_area_nosemaphore
;
672 * When running in the kernel we expect faults to occur only to
673 * addresses in user space. All other faults represent errors in the
674 * kernel and should generate an OOPS. Unfortunately, in the case of an
675 * erroneous fault occurring in a code path which already holds mmap_sem
676 * we will deadlock attempting to validate the fault against the
677 * address space. Luckily the kernel only validly references user
678 * space from well defined areas of code, which are listed in the
681 * As the vast majority of faults will be valid we will only perform
682 * the source reference check when there is a possibility of a deadlock.
683 * Attempt to lock the address space, if we cannot we then validate the
684 * source. If this is invalid we can skip the address space check,
685 * thus avoiding the deadlock.
687 if (!down_read_trylock(&mm
->mmap_sem
)) {
688 if ((error_code
& PF_USER
) == 0 &&
689 !search_exception_tables(regs
->ip
))
690 goto bad_area_nosemaphore
;
691 down_read(&mm
->mmap_sem
);
694 vma
= find_vma(mm
, address
);
697 if (vma
->vm_start
<= address
)
699 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
701 if (error_code
& PF_USER
) {
703 * Accessing the stack below %sp is always a bug.
704 * The large cushion allows instructions like enter
705 * and pusha to work. ("enter $65535,$31" pushes
706 * 32 pointers and then decrements %sp by 65535.)
708 if (address
+ 65536 + 32 * sizeof(unsigned long) < regs
->sp
)
711 if (expand_stack(vma
, address
))
714 * Ok, we have a good vm_area for this memory access, so
718 si_code
= SEGV_ACCERR
;
720 switch (error_code
& (PF_PROT
|PF_WRITE
)) {
721 default: /* 3: write, present */
723 case PF_WRITE
: /* write, not present */
724 if (!(vma
->vm_flags
& VM_WRITE
))
728 case PF_PROT
: /* read, present */
730 case 0: /* read, not present */
731 if (!(vma
->vm_flags
& (VM_READ
| VM_EXEC
| VM_WRITE
)))
736 * If for any reason at all we couldn't handle the fault,
737 * make sure we exit gracefully rather than endlessly redo
740 fault
= handle_mm_fault(mm
, vma
, address
, write
);
741 if (unlikely(fault
& VM_FAULT_ERROR
)) {
742 if (fault
& VM_FAULT_OOM
)
744 else if (fault
& VM_FAULT_SIGBUS
)
748 if (fault
& VM_FAULT_MAJOR
)
755 * Did it hit the DOS screen memory VA from vm86 mode?
757 if (v8086_mode(regs
)) {
758 unsigned long bit
= (address
- 0xA0000) >> PAGE_SHIFT
;
760 tsk
->thread
.screen_bitmap
|= 1 << bit
;
763 up_read(&mm
->mmap_sem
);
767 * Something tried to access memory that isn't in our memory map..
768 * Fix it, but check if it's kernel or user first..
771 up_read(&mm
->mmap_sem
);
773 bad_area_nosemaphore
:
774 /* User mode accesses just cause a SIGSEGV */
775 if (error_code
& PF_USER
) {
777 * It's possible to have interrupts off here.
782 * Valid to do another page fault here because this one came
785 if (is_prefetch(regs
, address
, error_code
))
788 if (is_errata100(regs
, address
))
791 if (show_unhandled_signals
&& unhandled_signal(tsk
, SIGSEGV
) &&
792 printk_ratelimit()) {
794 "%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
795 task_pid_nr(tsk
) > 1 ? KERN_INFO
: KERN_EMERG
,
796 tsk
->comm
, task_pid_nr(tsk
), address
,
797 (void *) regs
->ip
, (void *) regs
->sp
, error_code
);
798 print_vma_addr(" in ", regs
->ip
);
802 tsk
->thread
.cr2
= address
;
803 /* Kernel addresses are always protection faults */
804 tsk
->thread
.error_code
= error_code
| (address
>= TASK_SIZE
);
805 tsk
->thread
.trap_no
= 14;
806 force_sig_info_fault(SIGSEGV
, si_code
, address
, tsk
);
810 if (is_f00f_bug(regs
, address
))
814 /* Are we prepared to handle this kernel fault? */
815 if (fixup_exception(regs
))
820 * Valid to do another page fault here, because if this fault
821 * had been triggered by is_prefetch fixup_exception would have
825 * Hall of shame of CPU/BIOS bugs.
827 if (is_prefetch(regs
, address
, error_code
))
830 if (is_errata93(regs
, address
))
834 * Oops. The kernel tried to access some bad page. We'll have to
835 * terminate things with extreme prejudice.
840 flags
= oops_begin();
843 show_fault_oops(regs
, error_code
, address
);
845 tsk
->thread
.cr2
= address
;
846 tsk
->thread
.trap_no
= 14;
847 tsk
->thread
.error_code
= error_code
;
850 die("Oops", regs
, error_code
);
855 if (__die("Oops", regs
, error_code
))
857 /* Executive summary in case the body of the oops scrolled away */
858 printk(KERN_EMERG
"CR2: %016lx\n", address
);
859 oops_end(flags
, regs
, sig
);
863 * We ran out of memory, or some other thing happened to us that made
864 * us unable to handle the page fault gracefully.
867 up_read(&mm
->mmap_sem
);
868 if (is_global_init(tsk
)) {
871 * Re-lookup the vma - in theory the vma tree might
877 printk("VM: killing process %s\n", tsk
->comm
);
878 if (error_code
& PF_USER
)
879 do_group_exit(SIGKILL
);
883 up_read(&mm
->mmap_sem
);
885 /* Kernel mode? Handle exceptions or die */
886 if (!(error_code
& PF_USER
))
889 /* User space => ok to do another page fault */
890 if (is_prefetch(regs
, address
, error_code
))
893 tsk
->thread
.cr2
= address
;
894 tsk
->thread
.error_code
= error_code
;
895 tsk
->thread
.trap_no
= 14;
896 force_sig_info_fault(SIGBUS
, BUS_ADRERR
, address
, tsk
);
899 DEFINE_SPINLOCK(pgd_lock
);
902 void vmalloc_sync_all(void)
904 unsigned long address
;
907 if (SHARED_KERNEL_PMD
)
910 for (address
= VMALLOC_START
& PMD_MASK
;
911 address
>= TASK_SIZE
&& address
< FIXADDR_TOP
;
912 address
+= PMD_SIZE
) {
916 spin_lock_irqsave(&pgd_lock
, flags
);
917 list_for_each_entry(page
, &pgd_list
, lru
) {
918 if (!vmalloc_sync_one(page_address(page
),
922 spin_unlock_irqrestore(&pgd_lock
, flags
);
924 #else /* CONFIG_X86_64 */
925 for (address
= VMALLOC_START
& PGDIR_MASK
; address
<= VMALLOC_END
;
926 address
+= PGDIR_SIZE
) {
927 const pgd_t
*pgd_ref
= pgd_offset_k(address
);
931 if (pgd_none(*pgd_ref
))
933 spin_lock_irqsave(&pgd_lock
, flags
);
934 list_for_each_entry(page
, &pgd_list
, lru
) {
936 pgd
= (pgd_t
*)page_address(page
) + pgd_index(address
);
938 set_pgd(pgd
, *pgd_ref
);
940 BUG_ON(pgd_page_vaddr(*pgd
) != pgd_page_vaddr(*pgd_ref
));
942 spin_unlock_irqrestore(&pgd_lock
, flags
);