Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
[linux/fpc-iii.git] / arch / x86 / mm / pat.c
blobf6ff57b7efa514e0a7e1ec47ac8472ea868c13fa
1 /*
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.
8 */
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/slab.h>
16 #include <linux/mm.h>
17 #include <linux/fs.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>
26 #include <asm/e820.h>
27 #include <asm/mtrr.h>
28 #include <asm/page.h>
29 #include <asm/msr.h>
30 #include <asm/pat.h>
31 #include <asm/io.h>
33 #include "pat_internal.h"
35 #ifdef CONFIG_X86_PAT
36 int __read_mostly pat_enabled = 1;
38 static inline void pat_disable(const char *reason)
40 pat_enabled = 0;
41 printk(KERN_INFO "%s\n", reason);
44 static int __init nopat(char *str)
46 pat_disable("PAT support disabled.");
47 return 0;
49 early_param("nopat", nopat);
50 #else
51 static inline void pat_disable(const char *reason)
53 (void)reason;
55 #endif
58 int pat_debug_enable;
60 static int __init pat_debug_setup(char *str)
62 pat_debug_enable = 1;
63 return 0;
65 __setup("debugpat", pat_debug_setup);
67 static u64 __read_mostly boot_pat_state;
69 enum {
70 PAT_UC = 0, /* uncached */
71 PAT_WC = 1, /* Write combining */
72 PAT_WT = 4, /* Write Through */
73 PAT_WP = 5, /* Write Protected */
74 PAT_WB = 6, /* Write Back (default) */
75 PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */
78 #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
80 void pat_init(void)
82 u64 pat;
83 bool boot_cpu = !boot_pat_state;
85 if (!pat_enabled)
86 return;
88 if (!cpu_has_pat) {
89 if (!boot_pat_state) {
90 pat_disable("PAT not supported by CPU.");
91 return;
92 } else {
94 * If this happens we are on a secondary CPU, but
95 * switched to PAT on the boot CPU. We have no way to
96 * undo PAT.
98 printk(KERN_ERR "PAT enabled, "
99 "but not supported by secondary CPU\n");
100 BUG();
104 /* Set PWT to Write-Combining. All other bits stay the same */
106 * PTE encoding used in Linux:
107 * PAT
108 * |PCD
109 * ||PWT
110 * |||
111 * 000 WB _PAGE_CACHE_WB
112 * 001 WC _PAGE_CACHE_WC
113 * 010 UC- _PAGE_CACHE_UC_MINUS
114 * 011 UC _PAGE_CACHE_UC
115 * PAT bit unused
117 pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
118 PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
120 /* Boot CPU check */
121 if (!boot_pat_state)
122 rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
124 wrmsrl(MSR_IA32_CR_PAT, pat);
126 if (boot_cpu)
127 printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
128 smp_processor_id(), boot_pat_state, pat);
131 #undef PAT
133 static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */
136 * Does intersection of PAT memory type and MTRR memory type and returns
137 * the resulting memory type as PAT understands it.
138 * (Type in pat and mtrr will not have same value)
139 * The intersection is based on "Effective Memory Type" tables in IA-32
140 * SDM vol 3a
142 static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
145 * Look for MTRR hint to get the effective type in case where PAT
146 * request is for WB.
148 if (req_type == _PAGE_CACHE_WB) {
149 u8 mtrr_type;
151 mtrr_type = mtrr_type_lookup(start, end);
152 if (mtrr_type != MTRR_TYPE_WRBACK)
153 return _PAGE_CACHE_UC_MINUS;
155 return _PAGE_CACHE_WB;
158 return req_type;
161 static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end)
163 int ram_page = 0, not_rampage = 0;
164 unsigned long page_nr;
166 for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
167 ++page_nr) {
169 * For legacy reasons, physical address range in the legacy ISA
170 * region is tracked as non-RAM. This will allow users of
171 * /dev/mem to map portions of legacy ISA region, even when
172 * some of those portions are listed(or not even listed) with
173 * different e820 types(RAM/reserved/..)
175 if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) &&
176 page_is_ram(page_nr))
177 ram_page = 1;
178 else
179 not_rampage = 1;
181 if (ram_page == not_rampage)
182 return -1;
185 return ram_page;
189 * For RAM pages, we use page flags to mark the pages with appropriate type.
190 * Here we do two pass:
191 * - Find the memtype of all the pages in the range, look for any conflicts
192 * - In case of no conflicts, set the new memtype for pages in the range
194 static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type,
195 unsigned long *new_type)
197 struct page *page;
198 u64 pfn;
200 if (req_type == _PAGE_CACHE_UC) {
201 /* We do not support strong UC */
202 WARN_ON_ONCE(1);
203 req_type = _PAGE_CACHE_UC_MINUS;
206 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
207 unsigned long type;
209 page = pfn_to_page(pfn);
210 type = get_page_memtype(page);
211 if (type != -1) {
212 printk(KERN_INFO "reserve_ram_pages_type failed "
213 "0x%Lx-0x%Lx, track 0x%lx, req 0x%lx\n",
214 start, end, type, req_type);
215 if (new_type)
216 *new_type = type;
218 return -EBUSY;
222 if (new_type)
223 *new_type = req_type;
225 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
226 page = pfn_to_page(pfn);
227 set_page_memtype(page, req_type);
229 return 0;
232 static int free_ram_pages_type(u64 start, u64 end)
234 struct page *page;
235 u64 pfn;
237 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
238 page = pfn_to_page(pfn);
239 set_page_memtype(page, -1);
241 return 0;
245 * req_type typically has one of the:
246 * - _PAGE_CACHE_WB
247 * - _PAGE_CACHE_WC
248 * - _PAGE_CACHE_UC_MINUS
249 * - _PAGE_CACHE_UC
251 * If new_type is NULL, function will return an error if it cannot reserve the
252 * region with req_type. If new_type is non-NULL, function will return
253 * available type in new_type in case of no error. In case of any error
254 * it will return a negative return value.
256 int reserve_memtype(u64 start, u64 end, unsigned long req_type,
257 unsigned long *new_type)
259 struct memtype *new;
260 unsigned long actual_type;
261 int is_range_ram;
262 int err = 0;
264 BUG_ON(start >= end); /* end is exclusive */
266 if (!pat_enabled) {
267 /* This is identical to page table setting without PAT */
268 if (new_type) {
269 if (req_type == _PAGE_CACHE_WC)
270 *new_type = _PAGE_CACHE_UC_MINUS;
271 else
272 *new_type = req_type & _PAGE_CACHE_MASK;
274 return 0;
277 /* Low ISA region is always mapped WB in page table. No need to track */
278 if (x86_platform.is_untracked_pat_range(start, end)) {
279 if (new_type)
280 *new_type = _PAGE_CACHE_WB;
281 return 0;
285 * Call mtrr_lookup to get the type hint. This is an
286 * optimization for /dev/mem mmap'ers into WB memory (BIOS
287 * tools and ACPI tools). Use WB request for WB memory and use
288 * UC_MINUS otherwise.
290 actual_type = pat_x_mtrr_type(start, end, req_type & _PAGE_CACHE_MASK);
292 if (new_type)
293 *new_type = actual_type;
295 is_range_ram = pat_pagerange_is_ram(start, end);
296 if (is_range_ram == 1) {
298 err = reserve_ram_pages_type(start, end, req_type, new_type);
300 return err;
301 } else if (is_range_ram < 0) {
302 return -EINVAL;
305 new = kzalloc(sizeof(struct memtype), GFP_KERNEL);
306 if (!new)
307 return -ENOMEM;
309 new->start = start;
310 new->end = end;
311 new->type = actual_type;
313 spin_lock(&memtype_lock);
315 err = rbt_memtype_check_insert(new, new_type);
316 if (err) {
317 printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
318 "track %s, req %s\n",
319 start, end, cattr_name(new->type), cattr_name(req_type));
320 kfree(new);
321 spin_unlock(&memtype_lock);
323 return err;
326 spin_unlock(&memtype_lock);
328 dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
329 start, end, cattr_name(new->type), cattr_name(req_type),
330 new_type ? cattr_name(*new_type) : "-");
332 return err;
335 int free_memtype(u64 start, u64 end)
337 int err = -EINVAL;
338 int is_range_ram;
339 struct memtype *entry;
341 if (!pat_enabled)
342 return 0;
344 /* Low ISA region is always mapped WB. No need to track */
345 if (x86_platform.is_untracked_pat_range(start, end))
346 return 0;
348 is_range_ram = pat_pagerange_is_ram(start, end);
349 if (is_range_ram == 1) {
351 err = free_ram_pages_type(start, end);
353 return err;
354 } else if (is_range_ram < 0) {
355 return -EINVAL;
358 spin_lock(&memtype_lock);
359 entry = rbt_memtype_erase(start, end);
360 spin_unlock(&memtype_lock);
362 if (!entry) {
363 printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
364 current->comm, current->pid, start, end);
365 return -EINVAL;
368 kfree(entry);
370 dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
372 return 0;
377 * lookup_memtype - Looksup the memory type for a physical address
378 * @paddr: physical address of which memory type needs to be looked up
380 * Only to be called when PAT is enabled
382 * Returns _PAGE_CACHE_WB, _PAGE_CACHE_WC, _PAGE_CACHE_UC_MINUS or
383 * _PAGE_CACHE_UC
385 static unsigned long lookup_memtype(u64 paddr)
387 int rettype = _PAGE_CACHE_WB;
388 struct memtype *entry;
390 if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
391 return rettype;
393 if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
394 struct page *page;
395 page = pfn_to_page(paddr >> PAGE_SHIFT);
396 rettype = get_page_memtype(page);
398 * -1 from get_page_memtype() implies RAM page is in its
399 * default state and not reserved, and hence of type WB
401 if (rettype == -1)
402 rettype = _PAGE_CACHE_WB;
404 return rettype;
407 spin_lock(&memtype_lock);
409 entry = rbt_memtype_lookup(paddr);
410 if (entry != NULL)
411 rettype = entry->type;
412 else
413 rettype = _PAGE_CACHE_UC_MINUS;
415 spin_unlock(&memtype_lock);
416 return rettype;
420 * io_reserve_memtype - Request a memory type mapping for a region of memory
421 * @start: start (physical address) of the region
422 * @end: end (physical address) of the region
423 * @type: A pointer to memtype, with requested type. On success, requested
424 * or any other compatible type that was available for the region is returned
426 * On success, returns 0
427 * On failure, returns non-zero
429 int io_reserve_memtype(resource_size_t start, resource_size_t end,
430 unsigned long *type)
432 resource_size_t size = end - start;
433 unsigned long req_type = *type;
434 unsigned long new_type;
435 int ret;
437 WARN_ON_ONCE(iomem_map_sanity_check(start, size));
439 ret = reserve_memtype(start, end, req_type, &new_type);
440 if (ret)
441 goto out_err;
443 if (!is_new_memtype_allowed(start, size, req_type, new_type))
444 goto out_free;
446 if (kernel_map_sync_memtype(start, size, new_type) < 0)
447 goto out_free;
449 *type = new_type;
450 return 0;
452 out_free:
453 free_memtype(start, end);
454 ret = -EBUSY;
455 out_err:
456 return ret;
460 * io_free_memtype - Release a memory type mapping for a region of memory
461 * @start: start (physical address) of the region
462 * @end: end (physical address) of the region
464 void io_free_memtype(resource_size_t start, resource_size_t end)
466 free_memtype(start, end);
469 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
470 unsigned long size, pgprot_t vma_prot)
472 return vma_prot;
475 #ifdef CONFIG_STRICT_DEVMEM
476 /* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/
477 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
479 return 1;
481 #else
482 /* This check is needed to avoid cache aliasing when PAT is enabled */
483 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
485 u64 from = ((u64)pfn) << PAGE_SHIFT;
486 u64 to = from + size;
487 u64 cursor = from;
489 if (!pat_enabled)
490 return 1;
492 while (cursor < to) {
493 if (!devmem_is_allowed(pfn)) {
494 printk(KERN_INFO
495 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
496 current->comm, from, to);
497 return 0;
499 cursor += PAGE_SIZE;
500 pfn++;
502 return 1;
504 #endif /* CONFIG_STRICT_DEVMEM */
506 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
507 unsigned long size, pgprot_t *vma_prot)
509 unsigned long flags = _PAGE_CACHE_WB;
511 if (!range_is_allowed(pfn, size))
512 return 0;
514 if (file->f_flags & O_DSYNC)
515 flags = _PAGE_CACHE_UC_MINUS;
517 #ifdef CONFIG_X86_32
519 * On the PPro and successors, the MTRRs are used to set
520 * memory types for physical addresses outside main memory,
521 * so blindly setting UC or PWT on those pages is wrong.
522 * For Pentiums and earlier, the surround logic should disable
523 * caching for the high addresses through the KEN pin, but
524 * we maintain the tradition of paranoia in this code.
526 if (!pat_enabled &&
527 !(boot_cpu_has(X86_FEATURE_MTRR) ||
528 boot_cpu_has(X86_FEATURE_K6_MTRR) ||
529 boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
530 boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
531 (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
532 flags = _PAGE_CACHE_UC;
534 #endif
536 *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
537 flags);
538 return 1;
542 * Change the memory type for the physial address range in kernel identity
543 * mapping space if that range is a part of identity map.
545 int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
547 unsigned long id_sz;
549 if (base >= __pa(high_memory))
550 return 0;
552 id_sz = (__pa(high_memory) < base + size) ?
553 __pa(high_memory) - base :
554 size;
556 if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) {
557 printk(KERN_INFO
558 "%s:%d ioremap_change_attr failed %s "
559 "for %Lx-%Lx\n",
560 current->comm, current->pid,
561 cattr_name(flags),
562 base, (unsigned long long)(base + size));
563 return -EINVAL;
565 return 0;
569 * Internal interface to reserve a range of physical memory with prot.
570 * Reserved non RAM regions only and after successful reserve_memtype,
571 * this func also keeps identity mapping (if any) in sync with this new prot.
573 static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
574 int strict_prot)
576 int is_ram = 0;
577 int ret;
578 unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
579 unsigned long flags = want_flags;
581 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
584 * reserve_pfn_range() for RAM pages. We do not refcount to keep
585 * track of number of mappings of RAM pages. We can assert that
586 * the type requested matches the type of first page in the range.
588 if (is_ram) {
589 if (!pat_enabled)
590 return 0;
592 flags = lookup_memtype(paddr);
593 if (want_flags != flags) {
594 printk(KERN_WARNING
595 "%s:%d map pfn RAM range req %s for %Lx-%Lx, got %s\n",
596 current->comm, current->pid,
597 cattr_name(want_flags),
598 (unsigned long long)paddr,
599 (unsigned long long)(paddr + size),
600 cattr_name(flags));
601 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
602 (~_PAGE_CACHE_MASK)) |
603 flags);
605 return 0;
608 ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
609 if (ret)
610 return ret;
612 if (flags != want_flags) {
613 if (strict_prot ||
614 !is_new_memtype_allowed(paddr, size, want_flags, flags)) {
615 free_memtype(paddr, paddr + size);
616 printk(KERN_ERR "%s:%d map pfn expected mapping type %s"
617 " for %Lx-%Lx, got %s\n",
618 current->comm, current->pid,
619 cattr_name(want_flags),
620 (unsigned long long)paddr,
621 (unsigned long long)(paddr + size),
622 cattr_name(flags));
623 return -EINVAL;
626 * We allow returning different type than the one requested in
627 * non strict case.
629 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
630 (~_PAGE_CACHE_MASK)) |
631 flags);
634 if (kernel_map_sync_memtype(paddr, size, flags) < 0) {
635 free_memtype(paddr, paddr + size);
636 return -EINVAL;
638 return 0;
642 * Internal interface to free a range of physical memory.
643 * Frees non RAM regions only.
645 static void free_pfn_range(u64 paddr, unsigned long size)
647 int is_ram;
649 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
650 if (is_ram == 0)
651 free_memtype(paddr, paddr + size);
655 * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
656 * copied through copy_page_range().
658 * If the vma has a linear pfn mapping for the entire range, we get the prot
659 * from pte and reserve the entire vma range with single reserve_pfn_range call.
661 int track_pfn_vma_copy(struct vm_area_struct *vma)
663 resource_size_t paddr;
664 unsigned long prot;
665 unsigned long vma_size = vma->vm_end - vma->vm_start;
666 pgprot_t pgprot;
668 if (is_linear_pfn_mapping(vma)) {
670 * reserve the whole chunk covered by vma. We need the
671 * starting address and protection from pte.
673 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
674 WARN_ON_ONCE(1);
675 return -EINVAL;
677 pgprot = __pgprot(prot);
678 return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
681 return 0;
685 * track_pfn_vma_new is called when a _new_ pfn mapping is being established
686 * for physical range indicated by pfn and size.
688 * prot is passed in as a parameter for the new mapping. If the vma has a
689 * linear pfn mapping for the entire range reserve the entire vma range with
690 * single reserve_pfn_range call.
692 int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
693 unsigned long pfn, unsigned long size)
695 unsigned long flags;
696 resource_size_t paddr;
697 unsigned long vma_size = vma->vm_end - vma->vm_start;
699 if (is_linear_pfn_mapping(vma)) {
700 /* reserve the whole chunk starting from vm_pgoff */
701 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
702 return reserve_pfn_range(paddr, vma_size, prot, 0);
705 if (!pat_enabled)
706 return 0;
708 /* for vm_insert_pfn and friends, we set prot based on lookup */
709 flags = lookup_memtype(pfn << PAGE_SHIFT);
710 *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
711 flags);
713 return 0;
717 * untrack_pfn_vma is called while unmapping a pfnmap for a region.
718 * untrack can be called for a specific region indicated by pfn and size or
719 * can be for the entire vma (in which case size can be zero).
721 void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
722 unsigned long size)
724 resource_size_t paddr;
725 unsigned long vma_size = vma->vm_end - vma->vm_start;
727 if (is_linear_pfn_mapping(vma)) {
728 /* free the whole chunk starting from vm_pgoff */
729 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
730 free_pfn_range(paddr, vma_size);
731 return;
735 pgprot_t pgprot_writecombine(pgprot_t prot)
737 if (pat_enabled)
738 return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
739 else
740 return pgprot_noncached(prot);
742 EXPORT_SYMBOL_GPL(pgprot_writecombine);
744 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
746 static struct memtype *memtype_get_idx(loff_t pos)
748 struct memtype *print_entry;
749 int ret;
751 print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL);
752 if (!print_entry)
753 return NULL;
755 spin_lock(&memtype_lock);
756 ret = rbt_memtype_copy_nth_element(print_entry, pos);
757 spin_unlock(&memtype_lock);
759 if (!ret) {
760 return print_entry;
761 } else {
762 kfree(print_entry);
763 return NULL;
767 static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
769 if (*pos == 0) {
770 ++*pos;
771 seq_printf(seq, "PAT memtype list:\n");
774 return memtype_get_idx(*pos);
777 static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
779 ++*pos;
780 return memtype_get_idx(*pos);
783 static void memtype_seq_stop(struct seq_file *seq, void *v)
787 static int memtype_seq_show(struct seq_file *seq, void *v)
789 struct memtype *print_entry = (struct memtype *)v;
791 seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
792 print_entry->start, print_entry->end);
793 kfree(print_entry);
795 return 0;
798 static const struct seq_operations memtype_seq_ops = {
799 .start = memtype_seq_start,
800 .next = memtype_seq_next,
801 .stop = memtype_seq_stop,
802 .show = memtype_seq_show,
805 static int memtype_seq_open(struct inode *inode, struct file *file)
807 return seq_open(file, &memtype_seq_ops);
810 static const struct file_operations memtype_fops = {
811 .open = memtype_seq_open,
812 .read = seq_read,
813 .llseek = seq_lseek,
814 .release = seq_release,
817 static int __init pat_memtype_list_init(void)
819 if (pat_enabled) {
820 debugfs_create_file("pat_memtype_list", S_IRUSR,
821 arch_debugfs_dir, NULL, &memtype_fops);
823 return 0;
826 late_initcall(pat_memtype_list_init);
828 #endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */