2 * Handle caching attributes in page tables (PAT)
4 * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
5 * Suresh B Siddha <suresh.b.siddha@intel.com>
7 * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen.
10 #include <linux/seq_file.h>
11 #include <linux/bootmem.h>
12 #include <linux/debugfs.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/gfp.h>
18 #include <linux/rbtree.h>
20 #include <asm/cacheflush.h>
21 #include <asm/processor.h>
22 #include <asm/tlbflush.h>
23 #include <asm/x86_init.h>
24 #include <asm/pgtable.h>
25 #include <asm/fcntl.h>
34 int __read_mostly pat_enabled = 1;
36 static inline void pat_disable(const char *reason)
39 printk(KERN_INFO "%s\n", reason);
42 static int __init nopat(char *str)
44 pat_disable("PAT support disabled.");
47 early_param("nopat", nopat);
49 static inline void pat_disable(const char *reason)
56 static int debug_enable;
58 static int __init pat_debug_setup(char *str)
63 __setup("debugpat", pat_debug_setup);
65 #define dprintk(fmt, arg...) \
66 do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
69 static u64 __read_mostly boot_pat_state;
72 PAT_UC = 0, /* uncached */
73 PAT_WC = 1, /* Write combining */
74 PAT_WT = 4, /* Write Through */
75 PAT_WP = 5, /* Write Protected */
76 PAT_WB = 6, /* Write Back (default) */
77 PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */
80 #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
85 bool boot_cpu = !boot_pat_state;
91 if (!boot_pat_state) {
92 pat_disable("PAT not supported by CPU.");
96 * If this happens we are on a secondary CPU, but
97 * switched to PAT on the boot CPU. We have no way to
100 printk(KERN_ERR "PAT enabled, "
101 "but not supported by secondary CPU\n");
106 /* Set PWT to Write-Combining. All other bits stay the same */
108 * PTE encoding used in Linux:
113 * 000 WB _PAGE_CACHE_WB
114 * 001 WC _PAGE_CACHE_WC
115 * 010 UC- _PAGE_CACHE_UC_MINUS
116 * 011 UC _PAGE_CACHE_UC
119 pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
120 PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
124 rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
126 wrmsrl(MSR_IA32_CR_PAT, pat);
129 printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
130 smp_processor_id(), boot_pat_state, pat);
135 static char *cattr_name(unsigned long flags)
137 switch (flags & _PAGE_CACHE_MASK) {
138 case _PAGE_CACHE_UC: return "uncached";
139 case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
140 case _PAGE_CACHE_WB: return "write-back";
141 case _PAGE_CACHE_WC: return "write-combining";
142 default: return "broken";
147 * The global memtype list keeps track of memory type for specific
148 * physical memory areas. Conflicting memory types in different
149 * mappings can cause CPU cache corruption. To avoid this we keep track.
151 * The list is sorted based on starting address and can contain multiple
152 * entries for each address (this allows reference counting for overlapping
153 * areas). All the aliases have the same cache attributes of course.
154 * Zero attributes are represented as holes.
156 * The data structure is a list that is also organized as an rbtree
157 * sorted on the start address of memtype range.
159 * memtype_lock protects both the linear list and rbtree.
170 static struct rb_root memtype_rbroot = RB_ROOT;
171 static LIST_HEAD(memtype_list);
172 static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
174 static struct memtype *memtype_rb_search(struct rb_root *root, u64 start)
176 struct rb_node *node = root->rb_node;
177 struct memtype *last_lower = NULL;
180 struct memtype *data = container_of(node, struct memtype, rb);
182 if (data->start < start) {
184 node = node->rb_right;
185 } else if (data->start > start) {
186 node = node->rb_left;
191 /* Will return NULL if there is no entry with its start <= start */
195 static void memtype_rb_insert(struct rb_root *root, struct memtype *data)
197 struct rb_node **new = &(root->rb_node);
198 struct rb_node *parent = NULL;
201 struct memtype *this = container_of(*new, struct memtype, rb);
204 if (data->start <= this->start)
205 new = &((*new)->rb_left);
206 else if (data->start > this->start)
207 new = &((*new)->rb_right);
210 rb_link_node(&data->rb, parent, new);
211 rb_insert_color(&data->rb, root);
215 * Does intersection of PAT memory type and MTRR memory type and returns
216 * the resulting memory type as PAT understands it.
217 * (Type in pat and mtrr will not have same value)
218 * The intersection is based on "Effective Memory Type" tables in IA-32
221 static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
224 * Look for MTRR hint to get the effective type in case where PAT
227 if (req_type == _PAGE_CACHE_WB) {
230 mtrr_type = mtrr_type_lookup(start, end);
231 if (mtrr_type != MTRR_TYPE_WRBACK)
232 return _PAGE_CACHE_UC_MINUS;
234 return _PAGE_CACHE_WB;
241 chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
243 if (new->type != entry->type) {
245 new->type = entry->type;
251 /* check overlaps with more than one entry in the list */
252 list_for_each_entry_continue(entry, &memtype_list, nd) {
253 if (new->end <= entry->start)
255 else if (new->type != entry->type)
261 printk(KERN_INFO "%s:%d conflicting memory types "
262 "%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
263 new->end, cattr_name(new->type), cattr_name(entry->type));
267 static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
269 int ram_page = 0, not_rampage = 0;
270 unsigned long page_nr;
272 for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
275 * For legacy reasons, physical address range in the legacy ISA
276 * region is tracked as non-RAM. This will allow users of
277 * /dev/mem to map portions of legacy ISA region, even when
278 * some of those portions are listed(or not even listed) with
279 * different e820 types(RAM/reserved/..)
281 if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) &&
282 page_is_ram(page_nr))
287 if (ram_page == not_rampage)
295 * For RAM pages, we use page flags to mark the pages with appropriate type.
296 * Here we do two pass:
297 * - Find the memtype of all the pages in the range, look for any conflicts
298 * - In case of no conflicts, set the new memtype for pages in the range
300 * Caller must hold memtype_lock for atomicity.
302 static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type,
303 unsigned long *new_type)
308 if (req_type == _PAGE_CACHE_UC) {
309 /* We do not support strong UC */
311 req_type = _PAGE_CACHE_UC_MINUS;
314 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
317 page = pfn_to_page(pfn);
318 type = get_page_memtype(page);
320 printk(KERN_INFO "reserve_ram_pages_type failed "
321 "0x%Lx-0x%Lx, track 0x%lx, req 0x%lx\n",
322 start, end, type, req_type);
331 *new_type = req_type;
333 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
334 page = pfn_to_page(pfn);
335 set_page_memtype(page, req_type);
340 static int free_ram_pages_type(u64 start, u64 end)
345 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
346 page = pfn_to_page(pfn);
347 set_page_memtype(page, -1);
353 * req_type typically has one of the:
356 * - _PAGE_CACHE_UC_MINUS
359 * If new_type is NULL, function will return an error if it cannot reserve the
360 * region with req_type. If new_type is non-NULL, function will return
361 * available type in new_type in case of no error. In case of any error
362 * it will return a negative return value.
364 int reserve_memtype(u64 start, u64 end, unsigned long req_type,
365 unsigned long *new_type)
367 struct memtype *new, *entry;
368 unsigned long actual_type;
369 struct list_head *where;
373 BUG_ON(start >= end); /* end is exclusive */
376 /* This is identical to page table setting without PAT */
378 if (req_type == _PAGE_CACHE_WC)
379 *new_type = _PAGE_CACHE_UC_MINUS;
381 *new_type = req_type & _PAGE_CACHE_MASK;
386 /* Low ISA region is always mapped WB in page table. No need to track */
387 if (x86_platform.is_untracked_pat_range(start, end)) {
389 *new_type = _PAGE_CACHE_WB;
394 * Call mtrr_lookup to get the type hint. This is an
395 * optimization for /dev/mem mmap'ers into WB memory (BIOS
396 * tools and ACPI tools). Use WB request for WB memory and use
397 * UC_MINUS otherwise.
399 actual_type = pat_x_mtrr_type(start, end, req_type & _PAGE_CACHE_MASK);
402 *new_type = actual_type;
404 is_range_ram = pat_pagerange_is_ram(start, end);
405 if (is_range_ram == 1) {
407 spin_lock(&memtype_lock);
408 err = reserve_ram_pages_type(start, end, req_type, new_type);
409 spin_unlock(&memtype_lock);
412 } else if (is_range_ram < 0) {
416 new = kmalloc(sizeof(struct memtype), GFP_KERNEL);
422 new->type = actual_type;
424 spin_lock(&memtype_lock);
426 /* Search for existing mapping that overlaps the current range */
428 list_for_each_entry(entry, &memtype_list, nd) {
429 if (end <= entry->start) {
430 where = entry->nd.prev;
432 } else if (start <= entry->start) { /* end > entry->start */
433 err = chk_conflict(new, entry, new_type);
435 dprintk("Overlap at 0x%Lx-0x%Lx\n",
436 entry->start, entry->end);
437 where = entry->nd.prev;
440 } else if (start < entry->end) { /* start > entry->start */
441 err = chk_conflict(new, entry, new_type);
443 dprintk("Overlap at 0x%Lx-0x%Lx\n",
444 entry->start, entry->end);
447 * Move to right position in the linked
448 * list to add this new entry
450 list_for_each_entry_continue(entry,
452 if (start <= entry->start) {
453 where = entry->nd.prev;
463 printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
464 "track %s, req %s\n",
465 start, end, cattr_name(new->type), cattr_name(req_type));
467 spin_unlock(&memtype_lock);
473 list_add(&new->nd, where);
475 list_add_tail(&new->nd, &memtype_list);
477 memtype_rb_insert(&memtype_rbroot, new);
479 spin_unlock(&memtype_lock);
481 dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
482 start, end, cattr_name(new->type), cattr_name(req_type),
483 new_type ? cattr_name(*new_type) : "-");
488 int free_memtype(u64 start, u64 end)
490 struct memtype *entry, *saved_entry;
497 /* Low ISA region is always mapped WB. No need to track */
498 if (x86_platform.is_untracked_pat_range(start, end))
501 is_range_ram = pat_pagerange_is_ram(start, end);
502 if (is_range_ram == 1) {
504 spin_lock(&memtype_lock);
505 err = free_ram_pages_type(start, end);
506 spin_unlock(&memtype_lock);
509 } else if (is_range_ram < 0) {
513 spin_lock(&memtype_lock);
515 entry = memtype_rb_search(&memtype_rbroot, start);
516 if (unlikely(entry == NULL))
520 * Saved entry points to an entry with start same or less than what
521 * we searched for. Now go through the list in both directions to look
522 * for the entry that matches with both start and end, with list stored
523 * in sorted start address
526 list_for_each_entry_from(entry, &memtype_list, nd) {
527 if (entry->start == start && entry->end == end) {
528 rb_erase(&entry->rb, &memtype_rbroot);
529 list_del(&entry->nd);
533 } else if (entry->start > start) {
542 list_for_each_entry_reverse(entry, &memtype_list, nd) {
543 if (entry->start == start && entry->end == end) {
544 rb_erase(&entry->rb, &memtype_rbroot);
545 list_del(&entry->nd);
549 } else if (entry->start < start) {
554 spin_unlock(&memtype_lock);
557 printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
558 current->comm, current->pid, start, end);
561 dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
568 * lookup_memtype - Looksup the memory type for a physical address
569 * @paddr: physical address of which memory type needs to be looked up
571 * Only to be called when PAT is enabled
573 * Returns _PAGE_CACHE_WB, _PAGE_CACHE_WC, _PAGE_CACHE_UC_MINUS or
576 static unsigned long lookup_memtype(u64 paddr)
578 int rettype = _PAGE_CACHE_WB;
579 struct memtype *entry;
581 if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
584 if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
586 spin_lock(&memtype_lock);
587 page = pfn_to_page(paddr >> PAGE_SHIFT);
588 rettype = get_page_memtype(page);
589 spin_unlock(&memtype_lock);
591 * -1 from get_page_memtype() implies RAM page is in its
592 * default state and not reserved, and hence of type WB
595 rettype = _PAGE_CACHE_WB;
600 spin_lock(&memtype_lock);
602 entry = memtype_rb_search(&memtype_rbroot, paddr);
604 rettype = entry->type;
606 rettype = _PAGE_CACHE_UC_MINUS;
608 spin_unlock(&memtype_lock);
613 * io_reserve_memtype - Request a memory type mapping for a region of memory
614 * @start: start (physical address) of the region
615 * @end: end (physical address) of the region
616 * @type: A pointer to memtype, with requested type. On success, requested
617 * or any other compatible type that was available for the region is returned
619 * On success, returns 0
620 * On failure, returns non-zero
622 int io_reserve_memtype(resource_size_t start, resource_size_t end,
625 resource_size_t size = end - start;
626 unsigned long req_type = *type;
627 unsigned long new_type;
630 WARN_ON_ONCE(iomem_map_sanity_check(start, size));
632 ret = reserve_memtype(start, end, req_type, &new_type);
636 if (!is_new_memtype_allowed(start, size, req_type, new_type))
639 if (kernel_map_sync_memtype(start, size, new_type) < 0)
646 free_memtype(start, end);
653 * io_free_memtype - Release a memory type mapping for a region of memory
654 * @start: start (physical address) of the region
655 * @end: end (physical address) of the region
657 void io_free_memtype(resource_size_t start, resource_size_t end)
659 free_memtype(start, end);
662 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
663 unsigned long size, pgprot_t vma_prot)
668 #ifdef CONFIG_STRICT_DEVMEM
669 /* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/
670 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
675 /* This check is needed to avoid cache aliasing when PAT is enabled */
676 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
678 u64 from = ((u64)pfn) << PAGE_SHIFT;
679 u64 to = from + size;
685 while (cursor < to) {
686 if (!devmem_is_allowed(pfn)) {
688 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
689 current->comm, from, to);
697 #endif /* CONFIG_STRICT_DEVMEM */
699 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
700 unsigned long size, pgprot_t *vma_prot)
702 unsigned long flags = _PAGE_CACHE_WB;
704 if (!range_is_allowed(pfn, size))
707 if (file->f_flags & O_SYNC) {
708 flags = _PAGE_CACHE_UC_MINUS;
713 * On the PPro and successors, the MTRRs are used to set
714 * memory types for physical addresses outside main memory,
715 * so blindly setting UC or PWT on those pages is wrong.
716 * For Pentiums and earlier, the surround logic should disable
717 * caching for the high addresses through the KEN pin, but
718 * we maintain the tradition of paranoia in this code.
721 !(boot_cpu_has(X86_FEATURE_MTRR) ||
722 boot_cpu_has(X86_FEATURE_K6_MTRR) ||
723 boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
724 boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
725 (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
726 flags = _PAGE_CACHE_UC;
730 *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
736 * Change the memory type for the physial address range in kernel identity
737 * mapping space if that range is a part of identity map.
739 int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
743 if (base >= __pa(high_memory))
746 id_sz = (__pa(high_memory) < base + size) ?
747 __pa(high_memory) - base :
750 if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) {
752 "%s:%d ioremap_change_attr failed %s "
754 current->comm, current->pid,
756 base, (unsigned long long)(base + size));
763 * Internal interface to reserve a range of physical memory with prot.
764 * Reserved non RAM regions only and after successful reserve_memtype,
765 * this func also keeps identity mapping (if any) in sync with this new prot.
767 static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
772 unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
773 unsigned long flags = want_flags;
775 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
778 * reserve_pfn_range() for RAM pages. We do not refcount to keep
779 * track of number of mappings of RAM pages. We can assert that
780 * the type requested matches the type of first page in the range.
786 flags = lookup_memtype(paddr);
787 if (want_flags != flags) {
789 "%s:%d map pfn RAM range req %s for %Lx-%Lx, got %s\n",
790 current->comm, current->pid,
791 cattr_name(want_flags),
792 (unsigned long long)paddr,
793 (unsigned long long)(paddr + size),
795 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
796 (~_PAGE_CACHE_MASK)) |
802 ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
806 if (flags != want_flags) {
808 !is_new_memtype_allowed(paddr, size, want_flags, flags)) {
809 free_memtype(paddr, paddr + size);
810 printk(KERN_ERR "%s:%d map pfn expected mapping type %s"
811 " for %Lx-%Lx, got %s\n",
812 current->comm, current->pid,
813 cattr_name(want_flags),
814 (unsigned long long)paddr,
815 (unsigned long long)(paddr + size),
820 * We allow returning different type than the one requested in
823 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
824 (~_PAGE_CACHE_MASK)) |
828 if (kernel_map_sync_memtype(paddr, size, flags) < 0) {
829 free_memtype(paddr, paddr + size);
836 * Internal interface to free a range of physical memory.
837 * Frees non RAM regions only.
839 static void free_pfn_range(u64 paddr, unsigned long size)
843 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
845 free_memtype(paddr, paddr + size);
849 * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
850 * copied through copy_page_range().
852 * If the vma has a linear pfn mapping for the entire range, we get the prot
853 * from pte and reserve the entire vma range with single reserve_pfn_range call.
855 int track_pfn_vma_copy(struct vm_area_struct *vma)
857 resource_size_t paddr;
859 unsigned long vma_size = vma->vm_end - vma->vm_start;
862 if (is_linear_pfn_mapping(vma)) {
864 * reserve the whole chunk covered by vma. We need the
865 * starting address and protection from pte.
867 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
871 pgprot = __pgprot(prot);
872 return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
879 * track_pfn_vma_new is called when a _new_ pfn mapping is being established
880 * for physical range indicated by pfn and size.
882 * prot is passed in as a parameter for the new mapping. If the vma has a
883 * linear pfn mapping for the entire range reserve the entire vma range with
884 * single reserve_pfn_range call.
886 int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
887 unsigned long pfn, unsigned long size)
890 resource_size_t paddr;
891 unsigned long vma_size = vma->vm_end - vma->vm_start;
893 if (is_linear_pfn_mapping(vma)) {
894 /* reserve the whole chunk starting from vm_pgoff */
895 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
896 return reserve_pfn_range(paddr, vma_size, prot, 0);
902 /* for vm_insert_pfn and friends, we set prot based on lookup */
903 flags = lookup_memtype(pfn << PAGE_SHIFT);
904 *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
911 * untrack_pfn_vma is called while unmapping a pfnmap for a region.
912 * untrack can be called for a specific region indicated by pfn and size or
913 * can be for the entire vma (in which case size can be zero).
915 void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
918 resource_size_t paddr;
919 unsigned long vma_size = vma->vm_end - vma->vm_start;
921 if (is_linear_pfn_mapping(vma)) {
922 /* free the whole chunk starting from vm_pgoff */
923 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
924 free_pfn_range(paddr, vma_size);
929 pgprot_t pgprot_writecombine(pgprot_t prot)
932 return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
934 return pgprot_noncached(prot);
936 EXPORT_SYMBOL_GPL(pgprot_writecombine);
938 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
940 /* get Nth element of the linked list */
941 static struct memtype *memtype_get_idx(loff_t pos)
943 struct memtype *list_node, *print_entry;
946 print_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL);
950 spin_lock(&memtype_lock);
951 list_for_each_entry(list_node, &memtype_list, nd) {
953 *print_entry = *list_node;
954 spin_unlock(&memtype_lock);
959 spin_unlock(&memtype_lock);
965 static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
969 seq_printf(seq, "PAT memtype list:\n");
972 return memtype_get_idx(*pos);
975 static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
978 return memtype_get_idx(*pos);
981 static void memtype_seq_stop(struct seq_file *seq, void *v)
985 static int memtype_seq_show(struct seq_file *seq, void *v)
987 struct memtype *print_entry = (struct memtype *)v;
989 seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
990 print_entry->start, print_entry->end);
996 static const struct seq_operations memtype_seq_ops = {
997 .start = memtype_seq_start,
998 .next = memtype_seq_next,
999 .stop = memtype_seq_stop,
1000 .show = memtype_seq_show,
1003 static int memtype_seq_open(struct inode *inode, struct file *file)
1005 return seq_open(file, &memtype_seq_ops);
1008 static const struct file_operations memtype_fops = {
1009 .open = memtype_seq_open,
1011 .llseek = seq_lseek,
1012 .release = seq_release,
1015 static int __init pat_memtype_list_init(void)
1018 debugfs_create_file("pat_memtype_list", S_IRUSR,
1019 arch_debugfs_dir, NULL, &memtype_fops);
1024 late_initcall(pat_memtype_list_init);
1026 #endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */