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
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 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(struct pt_regs *regs,
413 unsigned long error_code, unsigned long address)
415 unsigned long flags = oops_begin();
417 struct task_struct *tsk = current;
419 printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
421 dump_pagetable(address);
422 tsk->thread.cr2 = address;
423 tsk->thread.trap_no = 14;
424 tsk->thread.error_code = error_code;
425 if (__die("Bad pagetable", regs, error_code))
427 oops_end(flags, regs, sig);
431 static noinline void no_context(struct pt_regs *regs,
432 unsigned long error_code, unsigned long address)
434 struct task_struct *tsk = current;
440 /* Are we prepared to handle this kernel fault? */
441 if (fixup_exception(regs))
446 * Valid to do another page fault here, because if this fault
447 * had been triggered by is_prefetch fixup_exception would have
451 * Hall of shame of CPU/BIOS bugs.
453 if (is_prefetch(regs, error_code, address))
456 if (is_errata93(regs, address))
460 * Oops. The kernel tried to access some bad page. We'll have to
461 * terminate things with extreme prejudice.
466 flags = oops_begin();
469 show_fault_oops(regs, error_code, address);
471 tsk->thread.cr2 = address;
472 tsk->thread.trap_no = 14;
473 tsk->thread.error_code = error_code;
476 die("Oops", regs, error_code);
481 if (__die("Oops", regs, error_code))
483 /* Executive summary in case the body of the oops scrolled away */
484 printk(KERN_EMERG "CR2: %016lx\n", address);
485 oops_end(flags, regs, sig);
489 static void __bad_area_nosemaphore(struct pt_regs *regs,
490 unsigned long error_code, unsigned long address,
493 struct task_struct *tsk = current;
495 /* User mode accesses just cause a SIGSEGV */
496 if (error_code & PF_USER) {
498 * It's possible to have interrupts off here.
503 * Valid to do another page fault here because this one came
506 if (is_prefetch(regs, error_code, address))
509 if (is_errata100(regs, address))
512 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
513 printk_ratelimit()) {
515 "%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
516 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
517 tsk->comm, task_pid_nr(tsk), address,
518 (void *) regs->ip, (void *) regs->sp, error_code);
519 print_vma_addr(" in ", regs->ip);
523 tsk->thread.cr2 = address;
524 /* Kernel addresses are always protection faults */
525 tsk->thread.error_code = error_code | (address >= TASK_SIZE);
526 tsk->thread.trap_no = 14;
527 force_sig_info_fault(SIGSEGV, si_code, address, tsk);
531 if (is_f00f_bug(regs, address))
534 no_context(regs, error_code, address);
537 static noinline void bad_area_nosemaphore(struct pt_regs *regs,
538 unsigned long error_code, unsigned long address)
540 __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
543 static void __bad_area(struct pt_regs *regs,
544 unsigned long error_code, unsigned long address,
547 struct mm_struct *mm = current->mm;
550 * Something tried to access memory that isn't in our memory map..
551 * Fix it, but check if it's kernel or user first..
553 up_read(&mm->mmap_sem);
555 __bad_area_nosemaphore(regs, error_code, address, si_code);
558 static noinline void bad_area(struct pt_regs *regs,
559 unsigned long error_code, unsigned long address)
561 __bad_area(regs, error_code, address, SEGV_MAPERR);
564 static noinline void bad_area_access_error(struct pt_regs *regs,
565 unsigned long error_code, unsigned long address)
567 __bad_area(regs, error_code, address, SEGV_ACCERR);
570 /* TODO: fixup for "mm-invoke-oom-killer-from-page-fault.patch" */
571 static void out_of_memory(struct pt_regs *regs,
572 unsigned long error_code, unsigned long address)
575 * We ran out of memory, call the OOM killer, and return the userspace
576 * (which will retry the fault, or kill us if we got oom-killed).
578 up_read(¤t->mm->mmap_sem);
579 pagefault_out_of_memory();
582 static void do_sigbus(struct pt_regs *regs,
583 unsigned long error_code, unsigned long address)
585 struct task_struct *tsk = current;
586 struct mm_struct *mm = tsk->mm;
588 up_read(&mm->mmap_sem);
590 /* Kernel mode? Handle exceptions or die */
591 if (!(error_code & PF_USER))
592 no_context(regs, error_code, address);
594 /* User space => ok to do another page fault */
595 if (is_prefetch(regs, error_code, address))
598 tsk->thread.cr2 = address;
599 tsk->thread.error_code = error_code;
600 tsk->thread.trap_no = 14;
601 force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
604 static noinline void mm_fault_error(struct pt_regs *regs,
605 unsigned long error_code, unsigned long address, unsigned int fault)
607 if (fault & VM_FAULT_OOM)
608 out_of_memory(regs, error_code, address);
609 else if (fault & VM_FAULT_SIGBUS)
610 do_sigbus(regs, error_code, address);
615 static int spurious_fault_check(unsigned long error_code, pte_t *pte)
617 if ((error_code & PF_WRITE) && !pte_write(*pte))
619 if ((error_code & PF_INSTR) && !pte_exec(*pte))
626 * Handle a spurious fault caused by a stale TLB entry. This allows
627 * us to lazily refresh the TLB when increasing the permissions of a
628 * kernel page (RO -> RW or NX -> X). Doing it eagerly is very
629 * expensive since that implies doing a full cross-processor TLB
630 * flush, even if no stale TLB entries exist on other processors.
631 * There are no security implications to leaving a stale TLB when
632 * increasing the permissions on a page.
634 static noinline int spurious_fault(unsigned long error_code,
635 unsigned long address)
642 /* Reserved-bit violation or user access to kernel space? */
643 if (error_code & (PF_USER | PF_RSVD))
646 pgd = init_mm.pgd + pgd_index(address);
647 if (!pgd_present(*pgd))
650 pud = pud_offset(pgd, address);
651 if (!pud_present(*pud))
655 return spurious_fault_check(error_code, (pte_t *) pud);
657 pmd = pmd_offset(pud, address);
658 if (!pmd_present(*pmd))
662 return spurious_fault_check(error_code, (pte_t *) pmd);
664 pte = pte_offset_kernel(pmd, address);
665 if (!pte_present(*pte))
668 return spurious_fault_check(error_code, pte);
673 * Handle a fault on the vmalloc or module mapping area
676 * Handle a fault on the vmalloc area
678 * This assumes no large pages in there.
680 static noinline int vmalloc_fault(unsigned long address)
683 unsigned long pgd_paddr;
687 /* Make sure we are in vmalloc area */
688 if (!(address >= VMALLOC_START && address < VMALLOC_END))
692 * Synchronize this task's top level page-table
693 * with the 'reference' page table.
695 * Do _not_ use "current" here. We might be inside
696 * an interrupt in the middle of a task switch..
698 pgd_paddr = read_cr3();
699 pmd_k = vmalloc_sync_one(__va(pgd_paddr), address);
702 pte_k = pte_offset_kernel(pmd_k, address);
703 if (!pte_present(*pte_k))
707 pgd_t *pgd, *pgd_ref;
708 pud_t *pud, *pud_ref;
709 pmd_t *pmd, *pmd_ref;
710 pte_t *pte, *pte_ref;
712 /* Make sure we are in vmalloc area */
713 if (!(address >= VMALLOC_START && address < VMALLOC_END))
716 /* Copy kernel mappings over when needed. This can also
717 happen within a race in page table update. In the later
720 pgd = pgd_offset(current->active_mm, address);
721 pgd_ref = pgd_offset_k(address);
722 if (pgd_none(*pgd_ref))
725 set_pgd(pgd, *pgd_ref);
727 BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
729 /* Below here mismatches are bugs because these lower tables
732 pud = pud_offset(pgd, address);
733 pud_ref = pud_offset(pgd_ref, address);
734 if (pud_none(*pud_ref))
736 if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
738 pmd = pmd_offset(pud, address);
739 pmd_ref = pmd_offset(pud_ref, address);
740 if (pmd_none(*pmd_ref))
742 if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
744 pte_ref = pte_offset_kernel(pmd_ref, address);
745 if (!pte_present(*pte_ref))
747 pte = pte_offset_kernel(pmd, address);
748 /* Don't use pte_page here, because the mappings can point
749 outside mem_map, and the NUMA hash lookup cannot handle
751 if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
757 int show_unhandled_signals = 1;
759 static inline int access_error(unsigned long error_code, int write,
760 struct vm_area_struct *vma)
763 /* write, present and write, not present */
764 if (unlikely(!(vma->vm_flags & VM_WRITE)))
766 } else if (unlikely(error_code & PF_PROT)) {
770 /* read, not present */
771 if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
779 * This routine handles page faults. It determines the address,
780 * and the problem, and then passes it off to one of the appropriate
786 void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
788 unsigned long address;
789 struct task_struct *tsk;
790 struct mm_struct *mm;
791 struct vm_area_struct *vma;
797 prefetchw(&mm->mmap_sem);
799 /* get the address */
800 address = read_cr2();
802 if (unlikely(notify_page_fault(regs)))
804 if (unlikely(kmmio_fault(regs, address)))
808 * We fault-in kernel-space virtual memory on-demand. The
809 * 'reference' page table is init_mm.pgd.
811 * NOTE! We MUST NOT take any locks for this case. We may
812 * be in an interrupt or a critical region, and should
813 * only copy the information from the master page table,
816 * This verifies that the fault happens in kernel space
817 * (error_code & 4) == 0, and that the fault was not a
818 * protection error (error_code & 9) == 0.
821 if (unlikely(address >= TASK_SIZE)) {
823 if (unlikely(address >= TASK_SIZE64)) {
825 if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
826 vmalloc_fault(address) >= 0)
829 /* Can handle a stale RO->RW TLB */
830 if (spurious_fault(error_code, address))
834 * Don't take the mm semaphore here. If we fixup a prefetch
835 * fault we could otherwise deadlock.
837 bad_area_nosemaphore(regs, error_code, address);
842 * It's safe to allow irq's after cr2 has been saved and the
843 * vmalloc fault has been handled.
845 * User-mode registers count as a user access even for any
846 * potential system fault or CPU buglet.
848 if (user_mode_vm(regs)) {
850 error_code |= PF_USER;
851 } else if (regs->flags & X86_EFLAGS_IF)
855 if (unlikely(error_code & PF_RSVD))
856 pgtable_bad(regs, error_code, address);
860 * If we're in an interrupt, have no user context or are running in an
861 * atomic region then we must not take the fault.
863 if (unlikely(in_atomic() || !mm)) {
864 bad_area_nosemaphore(regs, error_code, address);
869 * When running in the kernel we expect faults to occur only to
870 * addresses in user space. All other faults represent errors in the
871 * kernel and should generate an OOPS. Unfortunately, in the case of an
872 * erroneous fault occurring in a code path which already holds mmap_sem
873 * we will deadlock attempting to validate the fault against the
874 * address space. Luckily the kernel only validly references user
875 * space from well defined areas of code, which are listed in the
878 * As the vast majority of faults will be valid we will only perform
879 * the source reference check when there is a possibility of a deadlock.
880 * Attempt to lock the address space, if we cannot we then validate the
881 * source. If this is invalid we can skip the address space check,
882 * thus avoiding the deadlock.
884 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
885 if ((error_code & PF_USER) == 0 &&
886 !search_exception_tables(regs->ip)) {
887 bad_area_nosemaphore(regs, error_code, address);
890 down_read(&mm->mmap_sem);
893 vma = find_vma(mm, address);
894 if (unlikely(!vma)) {
895 bad_area(regs, error_code, address);
898 if (likely(vma->vm_start <= address))
900 if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
901 bad_area(regs, error_code, address);
904 if (error_code & PF_USER) {
906 * Accessing the stack below %sp is always a bug.
907 * The large cushion allows instructions like enter
908 * and pusha to work. ("enter $65535,$31" pushes
909 * 32 pointers and then decrements %sp by 65535.)
911 if (unlikely(address + 65536 + 32 * sizeof(unsigned long) < regs->sp)) {
912 bad_area(regs, error_code, address);
916 if (unlikely(expand_stack(vma, address))) {
917 bad_area(regs, error_code, address);
922 * Ok, we have a good vm_area for this memory access, so
926 write = error_code & PF_WRITE;
927 if (unlikely(access_error(error_code, write, vma))) {
928 bad_area_access_error(regs, error_code, address);
933 * If for any reason at all we couldn't handle the fault,
934 * make sure we exit gracefully rather than endlessly redo
937 fault = handle_mm_fault(mm, vma, address, write);
938 if (unlikely(fault & VM_FAULT_ERROR)) {
939 mm_fault_error(regs, error_code, address, fault);
942 if (fault & VM_FAULT_MAJOR)
949 * Did it hit the DOS screen memory VA from vm86 mode?
951 if (v8086_mode(regs)) {
952 unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;
954 tsk->thread.screen_bitmap |= 1 << bit;
957 up_read(&mm->mmap_sem);
960 DEFINE_SPINLOCK(pgd_lock);
963 void vmalloc_sync_all(void)
965 unsigned long address;
968 if (SHARED_KERNEL_PMD)
971 for (address = VMALLOC_START & PMD_MASK;
972 address >= TASK_SIZE && address < FIXADDR_TOP;
973 address += PMD_SIZE) {
977 spin_lock_irqsave(&pgd_lock, flags);
978 list_for_each_entry(page, &pgd_list, lru) {
979 if (!vmalloc_sync_one(page_address(page),
983 spin_unlock_irqrestore(&pgd_lock, flags);
985 #else /* CONFIG_X86_64 */
986 for (address = VMALLOC_START & PGDIR_MASK; address <= VMALLOC_END;
987 address += PGDIR_SIZE) {
988 const pgd_t *pgd_ref = pgd_offset_k(address);
992 if (pgd_none(*pgd_ref))
994 spin_lock_irqsave(&pgd_lock, flags);
995 list_for_each_entry(page, &pgd_list, lru) {
997 pgd = (pgd_t *)page_address(page) + pgd_index(address);
999 set_pgd(pgd, *pgd_ref);
1001 BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
1003 spin_unlock_irqrestore(&pgd_lock, flags);