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/slab.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>
33 #include "pat_internal.h"
34 #include "mm_internal.h"
37 #define pr_fmt(fmt) "" fmt
40 int __read_mostly pat_enabled = 1;
42 static inline void pat_disable(const char *reason)
45 pr_info("x86/PAT: %s\n", reason);
48 static int __init nopat(char *str)
50 pat_disable("PAT support disabled.");
53 early_param("nopat", nopat);
55 static inline void pat_disable(const char *reason)
64 static int __init pat_debug_setup(char *str)
69 __setup("debugpat", pat_debug_setup);
71 static u64 __read_mostly boot_pat_state;
75 * X86 PAT uses page flags WC and Uncached together to keep track of
76 * memory type of pages that have backing page struct. X86 PAT supports 3
77 * different memory types, _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC and
78 * _PAGE_CACHE_MODE_UC_MINUS and fourth state where page's memory type has not
79 * been changed from its default (value of -1 used to denote this).
80 * Note we do not support _PAGE_CACHE_MODE_UC here.
83 #define _PGMT_DEFAULT 0
84 #define _PGMT_WC (1UL << PG_arch_1)
85 #define _PGMT_UC_MINUS (1UL << PG_uncached)
86 #define _PGMT_WB (1UL << PG_uncached | 1UL << PG_arch_1)
87 #define _PGMT_MASK (1UL << PG_uncached | 1UL << PG_arch_1)
88 #define _PGMT_CLEAR_MASK (~_PGMT_MASK)
90 static inline enum page_cache_mode get_page_memtype(struct page *pg)
92 unsigned long pg_flags = pg->flags & _PGMT_MASK;
94 if (pg_flags == _PGMT_DEFAULT)
96 else if (pg_flags == _PGMT_WC)
97 return _PAGE_CACHE_MODE_WC;
98 else if (pg_flags == _PGMT_UC_MINUS)
99 return _PAGE_CACHE_MODE_UC_MINUS;
101 return _PAGE_CACHE_MODE_WB;
104 static inline void set_page_memtype(struct page *pg,
105 enum page_cache_mode memtype)
107 unsigned long memtype_flags;
108 unsigned long old_flags;
109 unsigned long new_flags;
112 case _PAGE_CACHE_MODE_WC:
113 memtype_flags = _PGMT_WC;
115 case _PAGE_CACHE_MODE_UC_MINUS:
116 memtype_flags = _PGMT_UC_MINUS;
118 case _PAGE_CACHE_MODE_WB:
119 memtype_flags = _PGMT_WB;
122 memtype_flags = _PGMT_DEFAULT;
127 old_flags = pg->flags;
128 new_flags = (old_flags & _PGMT_CLEAR_MASK) | memtype_flags;
129 } while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags);
132 static inline enum page_cache_mode get_page_memtype(struct page *pg)
136 static inline void set_page_memtype(struct page *pg,
137 enum page_cache_mode memtype)
143 PAT_UC = 0, /* uncached */
144 PAT_WC = 1, /* Write combining */
145 PAT_WT = 4, /* Write Through */
146 PAT_WP = 5, /* Write Protected */
147 PAT_WB = 6, /* Write Back (default) */
148 PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */
151 #define CM(c) (_PAGE_CACHE_MODE_ ## c)
153 static enum page_cache_mode pat_get_cache_mode(unsigned pat_val, char *msg)
155 enum page_cache_mode cache;
159 case PAT_UC: cache = CM(UC); cache_mode = "UC "; break;
160 case PAT_WC: cache = CM(WC); cache_mode = "WC "; break;
161 case PAT_WT: cache = CM(WT); cache_mode = "WT "; break;
162 case PAT_WP: cache = CM(WP); cache_mode = "WP "; break;
163 case PAT_WB: cache = CM(WB); cache_mode = "WB "; break;
164 case PAT_UC_MINUS: cache = CM(UC_MINUS); cache_mode = "UC- "; break;
165 default: cache = CM(WB); cache_mode = "WB "; break;
168 memcpy(msg, cache_mode, 4);
176 * Update the cache mode to pgprot translation tables according to PAT
178 * Using lower indices is preferred, so we start with highest index.
180 void pat_init_cache_modes(void)
183 enum page_cache_mode cache;
187 rdmsrl(MSR_IA32_CR_PAT, pat);
189 for (i = 7; i >= 0; i--) {
190 cache = pat_get_cache_mode((pat >> (i * 8)) & 7,
192 update_cache_mode_entry(i, cache);
194 pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg);
197 #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
202 bool boot_cpu = !boot_pat_state;
208 if (!boot_pat_state) {
209 pat_disable("PAT not supported by CPU.");
213 * If this happens we are on a secondary CPU, but
214 * switched to PAT on the boot CPU. We have no way to
217 pr_err("x86/PAT: PAT enabled, but not supported by secondary CPU\n");
222 /* Set PWT to Write-Combining. All other bits stay the same */
224 * PTE encoding used in Linux:
229 * 000 WB _PAGE_CACHE_WB
230 * 001 WC _PAGE_CACHE_WC
231 * 010 UC- _PAGE_CACHE_UC_MINUS
232 * 011 UC _PAGE_CACHE_UC
235 pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
236 PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
239 if (!boot_pat_state) {
240 rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
241 if (!boot_pat_state) {
242 pat_disable("PAT read returns always zero, disabled.");
247 wrmsrl(MSR_IA32_CR_PAT, pat);
250 pat_init_cache_modes();
255 static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */
258 * Does intersection of PAT memory type and MTRR memory type and returns
259 * the resulting memory type as PAT understands it.
260 * (Type in pat and mtrr will not have same value)
261 * The intersection is based on "Effective Memory Type" tables in IA-32
264 static unsigned long pat_x_mtrr_type(u64 start, u64 end,
265 enum page_cache_mode req_type)
268 * Look for MTRR hint to get the effective type in case where PAT
271 if (req_type == _PAGE_CACHE_MODE_WB) {
272 u8 mtrr_type, uniform;
274 mtrr_type = mtrr_type_lookup(start, end, &uniform);
275 if (mtrr_type != MTRR_TYPE_WRBACK)
276 return _PAGE_CACHE_MODE_UC_MINUS;
278 return _PAGE_CACHE_MODE_WB;
284 struct pagerange_state {
285 unsigned long cur_pfn;
291 pagerange_is_ram_callback(unsigned long initial_pfn, unsigned long total_nr_pages, void *arg)
293 struct pagerange_state *state = arg;
295 state->not_ram |= initial_pfn > state->cur_pfn;
296 state->ram |= total_nr_pages > 0;
297 state->cur_pfn = initial_pfn + total_nr_pages;
299 return state->ram && state->not_ram;
302 static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end)
305 unsigned long start_pfn = start >> PAGE_SHIFT;
306 unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
307 struct pagerange_state state = {start_pfn, 0, 0};
310 * For legacy reasons, physical address range in the legacy ISA
311 * region is tracked as non-RAM. This will allow users of
312 * /dev/mem to map portions of legacy ISA region, even when
313 * some of those portions are listed(or not even listed) with
314 * different e820 types(RAM/reserved/..)
316 if (start_pfn < ISA_END_ADDRESS >> PAGE_SHIFT)
317 start_pfn = ISA_END_ADDRESS >> PAGE_SHIFT;
319 if (start_pfn < end_pfn) {
320 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
321 &state, pagerange_is_ram_callback);
324 return (ret > 0) ? -1 : (state.ram ? 1 : 0);
328 * For RAM pages, we use page flags to mark the pages with appropriate type.
329 * Here we do two pass:
330 * - Find the memtype of all the pages in the range, look for any conflicts
331 * - In case of no conflicts, set the new memtype for pages in the range
333 static int reserve_ram_pages_type(u64 start, u64 end,
334 enum page_cache_mode req_type,
335 enum page_cache_mode *new_type)
340 if (req_type == _PAGE_CACHE_MODE_UC) {
341 /* We do not support strong UC */
343 req_type = _PAGE_CACHE_MODE_UC_MINUS;
346 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
347 enum page_cache_mode type;
349 page = pfn_to_page(pfn);
350 type = get_page_memtype(page);
352 pr_info("x86/PAT: reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n",
353 start, end - 1, type, req_type);
362 *new_type = req_type;
364 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
365 page = pfn_to_page(pfn);
366 set_page_memtype(page, req_type);
371 static int free_ram_pages_type(u64 start, u64 end)
376 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
377 page = pfn_to_page(pfn);
378 set_page_memtype(page, -1);
384 * req_type typically has one of the:
385 * - _PAGE_CACHE_MODE_WB
386 * - _PAGE_CACHE_MODE_WC
387 * - _PAGE_CACHE_MODE_UC_MINUS
388 * - _PAGE_CACHE_MODE_UC
390 * If new_type is NULL, function will return an error if it cannot reserve the
391 * region with req_type. If new_type is non-NULL, function will return
392 * available type in new_type in case of no error. In case of any error
393 * it will return a negative return value.
395 int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type,
396 enum page_cache_mode *new_type)
399 enum page_cache_mode actual_type;
403 BUG_ON(start >= end); /* end is exclusive */
406 /* This is identical to page table setting without PAT */
408 if (req_type == _PAGE_CACHE_MODE_WC)
409 *new_type = _PAGE_CACHE_MODE_UC_MINUS;
411 *new_type = req_type;
416 /* Low ISA region is always mapped WB in page table. No need to track */
417 if (x86_platform.is_untracked_pat_range(start, end)) {
419 *new_type = _PAGE_CACHE_MODE_WB;
424 * Call mtrr_lookup to get the type hint. This is an
425 * optimization for /dev/mem mmap'ers into WB memory (BIOS
426 * tools and ACPI tools). Use WB request for WB memory and use
427 * UC_MINUS otherwise.
429 actual_type = pat_x_mtrr_type(start, end, req_type);
432 *new_type = actual_type;
434 is_range_ram = pat_pagerange_is_ram(start, end);
435 if (is_range_ram == 1) {
437 err = reserve_ram_pages_type(start, end, req_type, new_type);
440 } else if (is_range_ram < 0) {
444 new = kzalloc(sizeof(struct memtype), GFP_KERNEL);
450 new->type = actual_type;
452 spin_lock(&memtype_lock);
454 err = rbt_memtype_check_insert(new, new_type);
456 pr_info("x86/PAT: reserve_memtype failed [mem %#010Lx-%#010Lx], track %s, req %s\n",
458 cattr_name(new->type), cattr_name(req_type));
460 spin_unlock(&memtype_lock);
465 spin_unlock(&memtype_lock);
467 dprintk("reserve_memtype added [mem %#010Lx-%#010Lx], track %s, req %s, ret %s\n",
468 start, end - 1, cattr_name(new->type), cattr_name(req_type),
469 new_type ? cattr_name(*new_type) : "-");
474 int free_memtype(u64 start, u64 end)
478 struct memtype *entry;
483 /* Low ISA region is always mapped WB. No need to track */
484 if (x86_platform.is_untracked_pat_range(start, end))
487 is_range_ram = pat_pagerange_is_ram(start, end);
488 if (is_range_ram == 1) {
490 err = free_ram_pages_type(start, end);
493 } else if (is_range_ram < 0) {
497 spin_lock(&memtype_lock);
498 entry = rbt_memtype_erase(start, end);
499 spin_unlock(&memtype_lock);
502 pr_info("x86/PAT: %s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n",
503 current->comm, current->pid, start, end - 1);
509 dprintk("free_memtype request [mem %#010Lx-%#010Lx]\n", start, end - 1);
516 * lookup_memtype - Looksup the memory type for a physical address
517 * @paddr: physical address of which memory type needs to be looked up
519 * Only to be called when PAT is enabled
521 * Returns _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC, _PAGE_CACHE_MODE_UC_MINUS
522 * or _PAGE_CACHE_MODE_UC
524 static enum page_cache_mode lookup_memtype(u64 paddr)
526 enum page_cache_mode rettype = _PAGE_CACHE_MODE_WB;
527 struct memtype *entry;
529 if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
532 if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
534 page = pfn_to_page(paddr >> PAGE_SHIFT);
535 rettype = get_page_memtype(page);
537 * -1 from get_page_memtype() implies RAM page is in its
538 * default state and not reserved, and hence of type WB
541 rettype = _PAGE_CACHE_MODE_WB;
546 spin_lock(&memtype_lock);
548 entry = rbt_memtype_lookup(paddr);
550 rettype = entry->type;
552 rettype = _PAGE_CACHE_MODE_UC_MINUS;
554 spin_unlock(&memtype_lock);
559 * io_reserve_memtype - Request a memory type mapping for a region of memory
560 * @start: start (physical address) of the region
561 * @end: end (physical address) of the region
562 * @type: A pointer to memtype, with requested type. On success, requested
563 * or any other compatible type that was available for the region is returned
565 * On success, returns 0
566 * On failure, returns non-zero
568 int io_reserve_memtype(resource_size_t start, resource_size_t end,
569 enum page_cache_mode *type)
571 resource_size_t size = end - start;
572 enum page_cache_mode req_type = *type;
573 enum page_cache_mode new_type;
576 WARN_ON_ONCE(iomem_map_sanity_check(start, size));
578 ret = reserve_memtype(start, end, req_type, &new_type);
582 if (!is_new_memtype_allowed(start, size, req_type, new_type))
585 if (kernel_map_sync_memtype(start, size, new_type) < 0)
592 free_memtype(start, end);
599 * io_free_memtype - Release a memory type mapping for a region of memory
600 * @start: start (physical address) of the region
601 * @end: end (physical address) of the region
603 void io_free_memtype(resource_size_t start, resource_size_t end)
605 free_memtype(start, end);
608 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
609 unsigned long size, pgprot_t vma_prot)
614 #ifdef CONFIG_STRICT_DEVMEM
615 /* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM */
616 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
621 /* This check is needed to avoid cache aliasing when PAT is enabled */
622 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
624 u64 from = ((u64)pfn) << PAGE_SHIFT;
625 u64 to = from + size;
631 while (cursor < to) {
632 if (!devmem_is_allowed(pfn)) {
633 pr_info("x86/PAT: Program %s tried to access /dev/mem between [mem %#010Lx-%#010Lx], PAT prevents it\n",
634 current->comm, from, to - 1);
642 #endif /* CONFIG_STRICT_DEVMEM */
644 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
645 unsigned long size, pgprot_t *vma_prot)
647 enum page_cache_mode pcm = _PAGE_CACHE_MODE_WB;
649 if (!range_is_allowed(pfn, size))
652 if (file->f_flags & O_DSYNC)
653 pcm = _PAGE_CACHE_MODE_UC_MINUS;
657 * On the PPro and successors, the MTRRs are used to set
658 * memory types for physical addresses outside main memory,
659 * so blindly setting UC or PWT on those pages is wrong.
660 * For Pentiums and earlier, the surround logic should disable
661 * caching for the high addresses through the KEN pin, but
662 * we maintain the tradition of paranoia in this code.
665 !(boot_cpu_has(X86_FEATURE_MTRR) ||
666 boot_cpu_has(X86_FEATURE_K6_MTRR) ||
667 boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
668 boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
669 (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
670 pcm = _PAGE_CACHE_MODE_UC;
674 *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
675 cachemode2protval(pcm));
680 * Change the memory type for the physial address range in kernel identity
681 * mapping space if that range is a part of identity map.
683 int kernel_map_sync_memtype(u64 base, unsigned long size,
684 enum page_cache_mode pcm)
688 if (base > __pa(high_memory-1))
692 * some areas in the middle of the kernel identity range
693 * are not mapped, like the PCI space.
695 if (!page_is_ram(base >> PAGE_SHIFT))
698 id_sz = (__pa(high_memory-1) <= base + size) ?
699 __pa(high_memory) - base :
702 if (ioremap_change_attr((unsigned long)__va(base), id_sz, pcm) < 0) {
703 pr_info("x86/PAT: %s:%d ioremap_change_attr failed %s for [mem %#010Lx-%#010Lx]\n",
704 current->comm, current->pid,
706 base, (unsigned long long)(base + size-1));
713 * Internal interface to reserve a range of physical memory with prot.
714 * Reserved non RAM regions only and after successful reserve_memtype,
715 * this func also keeps identity mapping (if any) in sync with this new prot.
717 static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
722 enum page_cache_mode want_pcm = pgprot2cachemode(*vma_prot);
723 enum page_cache_mode pcm = want_pcm;
725 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
728 * reserve_pfn_range() for RAM pages. We do not refcount to keep
729 * track of number of mappings of RAM pages. We can assert that
730 * the type requested matches the type of first page in the range.
736 pcm = lookup_memtype(paddr);
737 if (want_pcm != pcm) {
738 pr_warn("x86/PAT: %s:%d map pfn RAM range req %s for [mem %#010Lx-%#010Lx], got %s\n",
739 current->comm, current->pid,
740 cattr_name(want_pcm),
741 (unsigned long long)paddr,
742 (unsigned long long)(paddr + size - 1),
744 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
745 (~_PAGE_CACHE_MASK)) |
746 cachemode2protval(pcm));
751 ret = reserve_memtype(paddr, paddr + size, want_pcm, &pcm);
755 if (pcm != want_pcm) {
757 !is_new_memtype_allowed(paddr, size, want_pcm, pcm)) {
758 free_memtype(paddr, paddr + size);
759 pr_err("x86/PAT: %s:%d map pfn expected mapping type %s for [mem %#010Lx-%#010Lx], got %s\n",
760 current->comm, current->pid,
761 cattr_name(want_pcm),
762 (unsigned long long)paddr,
763 (unsigned long long)(paddr + size - 1),
768 * We allow returning different type than the one requested in
771 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
772 (~_PAGE_CACHE_MASK)) |
773 cachemode2protval(pcm));
776 if (kernel_map_sync_memtype(paddr, size, pcm) < 0) {
777 free_memtype(paddr, paddr + size);
784 * Internal interface to free a range of physical memory.
785 * Frees non RAM regions only.
787 static void free_pfn_range(u64 paddr, unsigned long size)
791 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
793 free_memtype(paddr, paddr + size);
797 * track_pfn_copy is called when vma that is covering the pfnmap gets
798 * copied through copy_page_range().
800 * If the vma has a linear pfn mapping for the entire range, we get the prot
801 * from pte and reserve the entire vma range with single reserve_pfn_range call.
803 int track_pfn_copy(struct vm_area_struct *vma)
805 resource_size_t paddr;
807 unsigned long vma_size = vma->vm_end - vma->vm_start;
810 if (vma->vm_flags & VM_PAT) {
812 * reserve the whole chunk covered by vma. We need the
813 * starting address and protection from pte.
815 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
819 pgprot = __pgprot(prot);
820 return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
827 * prot is passed in as a parameter for the new mapping. If the vma has a
828 * linear pfn mapping for the entire range reserve the entire vma range with
829 * single reserve_pfn_range call.
831 int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
832 unsigned long pfn, unsigned long addr, unsigned long size)
834 resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
835 enum page_cache_mode pcm;
837 /* reserve the whole chunk starting from paddr */
838 if (addr == vma->vm_start && size == (vma->vm_end - vma->vm_start)) {
841 ret = reserve_pfn_range(paddr, size, prot, 0);
843 vma->vm_flags |= VM_PAT;
851 * For anything smaller than the vma size we set prot based on the
854 pcm = lookup_memtype(paddr);
856 /* Check memtype for the remaining pages */
857 while (size > PAGE_SIZE) {
860 if (pcm != lookup_memtype(paddr))
864 *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
865 cachemode2protval(pcm));
870 int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
873 enum page_cache_mode pcm;
878 /* Set prot based on lookup */
879 pcm = lookup_memtype((resource_size_t)pfn << PAGE_SHIFT);
880 *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
881 cachemode2protval(pcm));
887 * untrack_pfn is called while unmapping a pfnmap for a region.
888 * untrack can be called for a specific region indicated by pfn and size or
889 * can be for the entire vma (in which case pfn, size are zero).
891 void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
894 resource_size_t paddr;
897 if (!(vma->vm_flags & VM_PAT))
900 /* free the chunk starting from pfn or the whole chunk */
901 paddr = (resource_size_t)pfn << PAGE_SHIFT;
902 if (!paddr && !size) {
903 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
908 size = vma->vm_end - vma->vm_start;
910 free_pfn_range(paddr, size);
911 vma->vm_flags &= ~VM_PAT;
914 pgprot_t pgprot_writecombine(pgprot_t prot)
917 return __pgprot(pgprot_val(prot) |
918 cachemode2protval(_PAGE_CACHE_MODE_WC));
920 return pgprot_noncached(prot);
922 EXPORT_SYMBOL_GPL(pgprot_writecombine);
924 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
926 static struct memtype *memtype_get_idx(loff_t pos)
928 struct memtype *print_entry;
931 print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL);
935 spin_lock(&memtype_lock);
936 ret = rbt_memtype_copy_nth_element(print_entry, pos);
937 spin_unlock(&memtype_lock);
947 static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
951 seq_puts(seq, "PAT memtype list:\n");
954 return memtype_get_idx(*pos);
957 static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
960 return memtype_get_idx(*pos);
963 static void memtype_seq_stop(struct seq_file *seq, void *v)
967 static int memtype_seq_show(struct seq_file *seq, void *v)
969 struct memtype *print_entry = (struct memtype *)v;
971 seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
972 print_entry->start, print_entry->end);
978 static const struct seq_operations memtype_seq_ops = {
979 .start = memtype_seq_start,
980 .next = memtype_seq_next,
981 .stop = memtype_seq_stop,
982 .show = memtype_seq_show,
985 static int memtype_seq_open(struct inode *inode, struct file *file)
987 return seq_open(file, &memtype_seq_ops);
990 static const struct file_operations memtype_fops = {
991 .open = memtype_seq_open,
994 .release = seq_release,
997 static int __init pat_memtype_list_init(void)
1000 debugfs_create_file("pat_memtype_list", S_IRUSR,
1001 arch_debugfs_dir, NULL, &memtype_fops);
1006 late_initcall(pat_memtype_list_init);
1008 #endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */