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
39 static bool boot_cpu_done;
41 static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
43 static inline void pat_disable(const char *reason)
46 pr_info("x86/PAT: %s\n", reason);
49 static int __init nopat(char *str)
51 pat_disable("PAT support disabled.");
54 early_param("nopat", nopat);
56 bool pat_enabled(void)
58 return !!__pat_enabled;
60 EXPORT_SYMBOL_GPL(pat_enabled);
64 static int __init pat_debug_setup(char *str)
69 __setup("debugpat", pat_debug_setup);
73 * X86 PAT uses page flags WC and Uncached together to keep track of
74 * memory type of pages that have backing page struct. X86 PAT supports 3
75 * different memory types, _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC and
76 * _PAGE_CACHE_MODE_UC_MINUS and fourth state where page's memory type has not
77 * been changed from its default (value of -1 used to denote this).
78 * Note we do not support _PAGE_CACHE_MODE_UC here.
81 #define _PGMT_DEFAULT 0
82 #define _PGMT_WC (1UL << PG_arch_1)
83 #define _PGMT_UC_MINUS (1UL << PG_uncached)
84 #define _PGMT_WB (1UL << PG_uncached | 1UL << PG_arch_1)
85 #define _PGMT_MASK (1UL << PG_uncached | 1UL << PG_arch_1)
86 #define _PGMT_CLEAR_MASK (~_PGMT_MASK)
88 static inline enum page_cache_mode get_page_memtype(struct page *pg)
90 unsigned long pg_flags = pg->flags & _PGMT_MASK;
92 if (pg_flags == _PGMT_DEFAULT)
94 else if (pg_flags == _PGMT_WC)
95 return _PAGE_CACHE_MODE_WC;
96 else if (pg_flags == _PGMT_UC_MINUS)
97 return _PAGE_CACHE_MODE_UC_MINUS;
99 return _PAGE_CACHE_MODE_WB;
102 static inline void set_page_memtype(struct page *pg,
103 enum page_cache_mode memtype)
105 unsigned long memtype_flags;
106 unsigned long old_flags;
107 unsigned long new_flags;
110 case _PAGE_CACHE_MODE_WC:
111 memtype_flags = _PGMT_WC;
113 case _PAGE_CACHE_MODE_UC_MINUS:
114 memtype_flags = _PGMT_UC_MINUS;
116 case _PAGE_CACHE_MODE_WB:
117 memtype_flags = _PGMT_WB;
120 memtype_flags = _PGMT_DEFAULT;
125 old_flags = pg->flags;
126 new_flags = (old_flags & _PGMT_CLEAR_MASK) | memtype_flags;
127 } while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags);
130 static inline enum page_cache_mode get_page_memtype(struct page *pg)
134 static inline void set_page_memtype(struct page *pg,
135 enum page_cache_mode memtype)
141 PAT_UC = 0, /* uncached */
142 PAT_WC = 1, /* Write combining */
143 PAT_WT = 4, /* Write Through */
144 PAT_WP = 5, /* Write Protected */
145 PAT_WB = 6, /* Write Back (default) */
146 PAT_UC_MINUS = 7, /* UC, but can be overriden by MTRR */
149 #define CM(c) (_PAGE_CACHE_MODE_ ## c)
151 static enum page_cache_mode pat_get_cache_mode(unsigned pat_val, char *msg)
153 enum page_cache_mode cache;
157 case PAT_UC: cache = CM(UC); cache_mode = "UC "; break;
158 case PAT_WC: cache = CM(WC); cache_mode = "WC "; break;
159 case PAT_WT: cache = CM(WT); cache_mode = "WT "; break;
160 case PAT_WP: cache = CM(WP); cache_mode = "WP "; break;
161 case PAT_WB: cache = CM(WB); cache_mode = "WB "; break;
162 case PAT_UC_MINUS: cache = CM(UC_MINUS); cache_mode = "UC- "; break;
163 default: cache = CM(WB); cache_mode = "WB "; break;
166 memcpy(msg, cache_mode, 4);
174 * Update the cache mode to pgprot translation tables according to PAT
176 * Using lower indices is preferred, so we start with highest index.
178 void pat_init_cache_modes(u64 pat)
180 enum page_cache_mode cache;
185 for (i = 7; i >= 0; i--) {
186 cache = pat_get_cache_mode((pat >> (i * 8)) & 7,
188 update_cache_mode_entry(i, cache);
190 pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg);
193 #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
195 static void pat_bsp_init(u64 pat)
200 pat_disable("PAT not supported by CPU.");
207 rdmsrl(MSR_IA32_CR_PAT, tmp_pat);
209 pat_disable("PAT MSR is 0, disabled.");
213 wrmsrl(MSR_IA32_CR_PAT, pat);
216 pat_init_cache_modes(pat);
219 static void pat_ap_init(u64 pat)
226 * If this happens we are on a secondary CPU, but switched to
227 * PAT on the boot CPU. We have no way to undo PAT.
229 panic("x86/PAT: PAT enabled, but not supported by secondary CPU\n");
232 wrmsrl(MSR_IA32_CR_PAT, pat);
239 if (!pat_enabled()) {
241 * No PAT. Emulate the PAT table that corresponds to the two
242 * cache bits, PWT (Write Through) and PCD (Cache Disable). This
243 * setup is the same as the BIOS default setup when the system
244 * has PAT but the "nopat" boot option has been specified. This
245 * emulated PAT table is used when MSR_IA32_CR_PAT returns 0.
252 * 00 0 WB : _PAGE_CACHE_MODE_WB
253 * 01 1 WT : _PAGE_CACHE_MODE_WT
254 * 10 2 UC-: _PAGE_CACHE_MODE_UC_MINUS
255 * 11 3 UC : _PAGE_CACHE_MODE_UC
257 * NOTE: When WC or WP is used, it is redirected to UC- per
258 * the default setup in __cachemode2pte_tbl[].
260 pat = PAT(0, WB) | PAT(1, WT) | PAT(2, UC_MINUS) | PAT(3, UC) |
261 PAT(4, WB) | PAT(5, WT) | PAT(6, UC_MINUS) | PAT(7, UC);
264 * PTE encoding used in Linux:
269 * 000 WB _PAGE_CACHE_WB
270 * 001 WC _PAGE_CACHE_WC
271 * 010 UC- _PAGE_CACHE_UC_MINUS
272 * 011 UC _PAGE_CACHE_UC
275 pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
276 PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
279 if (!boot_cpu_done) {
281 boot_cpu_done = true;
289 static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */
292 * Does intersection of PAT memory type and MTRR memory type and returns
293 * the resulting memory type as PAT understands it.
294 * (Type in pat and mtrr will not have same value)
295 * The intersection is based on "Effective Memory Type" tables in IA-32
298 static unsigned long pat_x_mtrr_type(u64 start, u64 end,
299 enum page_cache_mode req_type)
302 * Look for MTRR hint to get the effective type in case where PAT
305 if (req_type == _PAGE_CACHE_MODE_WB) {
306 u8 mtrr_type, uniform;
308 mtrr_type = mtrr_type_lookup(start, end, &uniform);
309 if (mtrr_type != MTRR_TYPE_WRBACK)
310 return _PAGE_CACHE_MODE_UC_MINUS;
312 return _PAGE_CACHE_MODE_WB;
318 struct pagerange_state {
319 unsigned long cur_pfn;
325 pagerange_is_ram_callback(unsigned long initial_pfn, unsigned long total_nr_pages, void *arg)
327 struct pagerange_state *state = arg;
329 state->not_ram |= initial_pfn > state->cur_pfn;
330 state->ram |= total_nr_pages > 0;
331 state->cur_pfn = initial_pfn + total_nr_pages;
333 return state->ram && state->not_ram;
336 static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end)
339 unsigned long start_pfn = start >> PAGE_SHIFT;
340 unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
341 struct pagerange_state state = {start_pfn, 0, 0};
344 * For legacy reasons, physical address range in the legacy ISA
345 * region is tracked as non-RAM. This will allow users of
346 * /dev/mem to map portions of legacy ISA region, even when
347 * some of those portions are listed(or not even listed) with
348 * different e820 types(RAM/reserved/..)
350 if (start_pfn < ISA_END_ADDRESS >> PAGE_SHIFT)
351 start_pfn = ISA_END_ADDRESS >> PAGE_SHIFT;
353 if (start_pfn < end_pfn) {
354 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
355 &state, pagerange_is_ram_callback);
358 return (ret > 0) ? -1 : (state.ram ? 1 : 0);
362 * For RAM pages, we use page flags to mark the pages with appropriate type.
363 * Here we do two pass:
364 * - Find the memtype of all the pages in the range, look for any conflicts
365 * - In case of no conflicts, set the new memtype for pages in the range
367 static int reserve_ram_pages_type(u64 start, u64 end,
368 enum page_cache_mode req_type,
369 enum page_cache_mode *new_type)
374 if (req_type == _PAGE_CACHE_MODE_UC) {
375 /* We do not support strong UC */
377 req_type = _PAGE_CACHE_MODE_UC_MINUS;
380 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
381 enum page_cache_mode type;
383 page = pfn_to_page(pfn);
384 type = get_page_memtype(page);
386 pr_info("x86/PAT: reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n",
387 start, end - 1, type, req_type);
396 *new_type = req_type;
398 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
399 page = pfn_to_page(pfn);
400 set_page_memtype(page, req_type);
405 static int free_ram_pages_type(u64 start, u64 end)
410 for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
411 page = pfn_to_page(pfn);
412 set_page_memtype(page, -1);
418 * req_type typically has one of the:
419 * - _PAGE_CACHE_MODE_WB
420 * - _PAGE_CACHE_MODE_WC
421 * - _PAGE_CACHE_MODE_UC_MINUS
422 * - _PAGE_CACHE_MODE_UC
424 * If new_type is NULL, function will return an error if it cannot reserve the
425 * region with req_type. If new_type is non-NULL, function will return
426 * available type in new_type in case of no error. In case of any error
427 * it will return a negative return value.
429 int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type,
430 enum page_cache_mode *new_type)
433 enum page_cache_mode actual_type;
437 BUG_ON(start >= end); /* end is exclusive */
439 if (!pat_enabled()) {
440 /* This is identical to page table setting without PAT */
442 if (req_type == _PAGE_CACHE_MODE_WC)
443 *new_type = _PAGE_CACHE_MODE_UC_MINUS;
445 *new_type = req_type;
450 /* Low ISA region is always mapped WB in page table. No need to track */
451 if (x86_platform.is_untracked_pat_range(start, end)) {
453 *new_type = _PAGE_CACHE_MODE_WB;
458 * Call mtrr_lookup to get the type hint. This is an
459 * optimization for /dev/mem mmap'ers into WB memory (BIOS
460 * tools and ACPI tools). Use WB request for WB memory and use
461 * UC_MINUS otherwise.
463 actual_type = pat_x_mtrr_type(start, end, req_type);
466 *new_type = actual_type;
468 is_range_ram = pat_pagerange_is_ram(start, end);
469 if (is_range_ram == 1) {
471 err = reserve_ram_pages_type(start, end, req_type, new_type);
474 } else if (is_range_ram < 0) {
478 new = kzalloc(sizeof(struct memtype), GFP_KERNEL);
484 new->type = actual_type;
486 spin_lock(&memtype_lock);
488 err = rbt_memtype_check_insert(new, new_type);
490 pr_info("x86/PAT: reserve_memtype failed [mem %#010Lx-%#010Lx], track %s, req %s\n",
492 cattr_name(new->type), cattr_name(req_type));
494 spin_unlock(&memtype_lock);
499 spin_unlock(&memtype_lock);
501 dprintk("reserve_memtype added [mem %#010Lx-%#010Lx], track %s, req %s, ret %s\n",
502 start, end - 1, cattr_name(new->type), cattr_name(req_type),
503 new_type ? cattr_name(*new_type) : "-");
508 int free_memtype(u64 start, u64 end)
512 struct memtype *entry;
517 /* Low ISA region is always mapped WB. No need to track */
518 if (x86_platform.is_untracked_pat_range(start, end))
521 is_range_ram = pat_pagerange_is_ram(start, end);
522 if (is_range_ram == 1) {
524 err = free_ram_pages_type(start, end);
527 } else if (is_range_ram < 0) {
531 spin_lock(&memtype_lock);
532 entry = rbt_memtype_erase(start, end);
533 spin_unlock(&memtype_lock);
536 pr_info("x86/PAT: %s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n",
537 current->comm, current->pid, start, end - 1);
543 dprintk("free_memtype request [mem %#010Lx-%#010Lx]\n", start, end - 1);
550 * lookup_memtype - Looksup the memory type for a physical address
551 * @paddr: physical address of which memory type needs to be looked up
553 * Only to be called when PAT is enabled
555 * Returns _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC, _PAGE_CACHE_MODE_UC_MINUS
556 * or _PAGE_CACHE_MODE_UC
558 static enum page_cache_mode lookup_memtype(u64 paddr)
560 enum page_cache_mode rettype = _PAGE_CACHE_MODE_WB;
561 struct memtype *entry;
563 if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
566 if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
568 page = pfn_to_page(paddr >> PAGE_SHIFT);
569 rettype = get_page_memtype(page);
571 * -1 from get_page_memtype() implies RAM page is in its
572 * default state and not reserved, and hence of type WB
575 rettype = _PAGE_CACHE_MODE_WB;
580 spin_lock(&memtype_lock);
582 entry = rbt_memtype_lookup(paddr);
584 rettype = entry->type;
586 rettype = _PAGE_CACHE_MODE_UC_MINUS;
588 spin_unlock(&memtype_lock);
593 * io_reserve_memtype - Request a memory type mapping for a region of memory
594 * @start: start (physical address) of the region
595 * @end: end (physical address) of the region
596 * @type: A pointer to memtype, with requested type. On success, requested
597 * or any other compatible type that was available for the region is returned
599 * On success, returns 0
600 * On failure, returns non-zero
602 int io_reserve_memtype(resource_size_t start, resource_size_t end,
603 enum page_cache_mode *type)
605 resource_size_t size = end - start;
606 enum page_cache_mode req_type = *type;
607 enum page_cache_mode new_type;
610 WARN_ON_ONCE(iomem_map_sanity_check(start, size));
612 ret = reserve_memtype(start, end, req_type, &new_type);
616 if (!is_new_memtype_allowed(start, size, req_type, new_type))
619 if (kernel_map_sync_memtype(start, size, new_type) < 0)
626 free_memtype(start, end);
633 * io_free_memtype - Release a memory type mapping for a region of memory
634 * @start: start (physical address) of the region
635 * @end: end (physical address) of the region
637 void io_free_memtype(resource_size_t start, resource_size_t end)
639 free_memtype(start, end);
642 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
643 unsigned long size, pgprot_t vma_prot)
648 #ifdef CONFIG_STRICT_DEVMEM
649 /* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM */
650 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
655 /* This check is needed to avoid cache aliasing when PAT is enabled */
656 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
658 u64 from = ((u64)pfn) << PAGE_SHIFT;
659 u64 to = from + size;
665 while (cursor < to) {
666 if (!devmem_is_allowed(pfn)) {
667 pr_info("x86/PAT: Program %s tried to access /dev/mem between [mem %#010Lx-%#010Lx], PAT prevents it\n",
668 current->comm, from, to - 1);
676 #endif /* CONFIG_STRICT_DEVMEM */
678 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
679 unsigned long size, pgprot_t *vma_prot)
681 enum page_cache_mode pcm = _PAGE_CACHE_MODE_WB;
683 if (!range_is_allowed(pfn, size))
686 if (file->f_flags & O_DSYNC)
687 pcm = _PAGE_CACHE_MODE_UC_MINUS;
691 * On the PPro and successors, the MTRRs are used to set
692 * memory types for physical addresses outside main memory,
693 * so blindly setting UC or PWT on those pages is wrong.
694 * For Pentiums and earlier, the surround logic should disable
695 * caching for the high addresses through the KEN pin, but
696 * we maintain the tradition of paranoia in this code.
698 if (!pat_enabled() &&
699 !(boot_cpu_has(X86_FEATURE_MTRR) ||
700 boot_cpu_has(X86_FEATURE_K6_MTRR) ||
701 boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
702 boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
703 (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
704 pcm = _PAGE_CACHE_MODE_UC;
708 *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
709 cachemode2protval(pcm));
714 * Change the memory type for the physial address range in kernel identity
715 * mapping space if that range is a part of identity map.
717 int kernel_map_sync_memtype(u64 base, unsigned long size,
718 enum page_cache_mode pcm)
722 if (base > __pa(high_memory-1))
726 * some areas in the middle of the kernel identity range
727 * are not mapped, like the PCI space.
729 if (!page_is_ram(base >> PAGE_SHIFT))
732 id_sz = (__pa(high_memory-1) <= base + size) ?
733 __pa(high_memory) - base :
736 if (ioremap_change_attr((unsigned long)__va(base), id_sz, pcm) < 0) {
737 pr_info("x86/PAT: %s:%d ioremap_change_attr failed %s for [mem %#010Lx-%#010Lx]\n",
738 current->comm, current->pid,
740 base, (unsigned long long)(base + size-1));
747 * Internal interface to reserve a range of physical memory with prot.
748 * Reserved non RAM regions only and after successful reserve_memtype,
749 * this func also keeps identity mapping (if any) in sync with this new prot.
751 static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
756 enum page_cache_mode want_pcm = pgprot2cachemode(*vma_prot);
757 enum page_cache_mode pcm = want_pcm;
759 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
762 * reserve_pfn_range() for RAM pages. We do not refcount to keep
763 * track of number of mappings of RAM pages. We can assert that
764 * the type requested matches the type of first page in the range.
770 pcm = lookup_memtype(paddr);
771 if (want_pcm != pcm) {
772 pr_warn("x86/PAT: %s:%d map pfn RAM range req %s for [mem %#010Lx-%#010Lx], got %s\n",
773 current->comm, current->pid,
774 cattr_name(want_pcm),
775 (unsigned long long)paddr,
776 (unsigned long long)(paddr + size - 1),
778 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
779 (~_PAGE_CACHE_MASK)) |
780 cachemode2protval(pcm));
785 ret = reserve_memtype(paddr, paddr + size, want_pcm, &pcm);
789 if (pcm != want_pcm) {
791 !is_new_memtype_allowed(paddr, size, want_pcm, pcm)) {
792 free_memtype(paddr, paddr + size);
793 pr_err("x86/PAT: %s:%d map pfn expected mapping type %s for [mem %#010Lx-%#010Lx], got %s\n",
794 current->comm, current->pid,
795 cattr_name(want_pcm),
796 (unsigned long long)paddr,
797 (unsigned long long)(paddr + size - 1),
802 * We allow returning different type than the one requested in
805 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
806 (~_PAGE_CACHE_MASK)) |
807 cachemode2protval(pcm));
810 if (kernel_map_sync_memtype(paddr, size, pcm) < 0) {
811 free_memtype(paddr, paddr + size);
818 * Internal interface to free a range of physical memory.
819 * Frees non RAM regions only.
821 static void free_pfn_range(u64 paddr, unsigned long size)
825 is_ram = pat_pagerange_is_ram(paddr, paddr + size);
827 free_memtype(paddr, paddr + size);
831 * track_pfn_copy is called when vma that is covering the pfnmap gets
832 * copied through copy_page_range().
834 * If the vma has a linear pfn mapping for the entire range, we get the prot
835 * from pte and reserve the entire vma range with single reserve_pfn_range call.
837 int track_pfn_copy(struct vm_area_struct *vma)
839 resource_size_t paddr;
841 unsigned long vma_size = vma->vm_end - vma->vm_start;
844 if (vma->vm_flags & VM_PAT) {
846 * reserve the whole chunk covered by vma. We need the
847 * starting address and protection from pte.
849 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
853 pgprot = __pgprot(prot);
854 return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
861 * prot is passed in as a parameter for the new mapping. If the vma has a
862 * linear pfn mapping for the entire range reserve the entire vma range with
863 * single reserve_pfn_range call.
865 int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
866 unsigned long pfn, unsigned long addr, unsigned long size)
868 resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
869 enum page_cache_mode pcm;
871 /* reserve the whole chunk starting from paddr */
872 if (addr == vma->vm_start && size == (vma->vm_end - vma->vm_start)) {
875 ret = reserve_pfn_range(paddr, size, prot, 0);
877 vma->vm_flags |= VM_PAT;
885 * For anything smaller than the vma size we set prot based on the
888 pcm = lookup_memtype(paddr);
890 /* Check memtype for the remaining pages */
891 while (size > PAGE_SIZE) {
894 if (pcm != lookup_memtype(paddr))
898 *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
899 cachemode2protval(pcm));
904 int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
907 enum page_cache_mode pcm;
912 /* Set prot based on lookup */
913 pcm = lookup_memtype((resource_size_t)pfn << PAGE_SHIFT);
914 *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
915 cachemode2protval(pcm));
921 * untrack_pfn is called while unmapping a pfnmap for a region.
922 * untrack can be called for a specific region indicated by pfn and size or
923 * can be for the entire vma (in which case pfn, size are zero).
925 void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
928 resource_size_t paddr;
931 if (!(vma->vm_flags & VM_PAT))
934 /* free the chunk starting from pfn or the whole chunk */
935 paddr = (resource_size_t)pfn << PAGE_SHIFT;
936 if (!paddr && !size) {
937 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
942 size = vma->vm_end - vma->vm_start;
944 free_pfn_range(paddr, size);
945 vma->vm_flags &= ~VM_PAT;
948 pgprot_t pgprot_writecombine(pgprot_t prot)
951 return __pgprot(pgprot_val(prot) |
952 cachemode2protval(_PAGE_CACHE_MODE_WC));
954 return pgprot_noncached(prot);
956 EXPORT_SYMBOL_GPL(pgprot_writecombine);
958 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
960 static struct memtype *memtype_get_idx(loff_t pos)
962 struct memtype *print_entry;
965 print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL);
969 spin_lock(&memtype_lock);
970 ret = rbt_memtype_copy_nth_element(print_entry, pos);
971 spin_unlock(&memtype_lock);
981 static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
985 seq_puts(seq, "PAT memtype list:\n");
988 return memtype_get_idx(*pos);
991 static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
994 return memtype_get_idx(*pos);
997 static void memtype_seq_stop(struct seq_file *seq, void *v)
1001 static int memtype_seq_show(struct seq_file *seq, void *v)
1003 struct memtype *print_entry = (struct memtype *)v;
1005 seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
1006 print_entry->start, print_entry->end);
1012 static const struct seq_operations memtype_seq_ops = {
1013 .start = memtype_seq_start,
1014 .next = memtype_seq_next,
1015 .stop = memtype_seq_stop,
1016 .show = memtype_seq_show,
1019 static int memtype_seq_open(struct inode *inode, struct file *file)
1021 return seq_open(file, &memtype_seq_ops);
1024 static const struct file_operations memtype_fops = {
1025 .open = memtype_seq_open,
1027 .llseek = seq_lseek,
1028 .release = seq_release,
1031 static int __init pat_memtype_list_init(void)
1033 if (pat_enabled()) {
1034 debugfs_create_file("pat_memtype_list", S_IRUSR,
1035 arch_debugfs_dir, NULL, &memtype_fops);
1040 late_initcall(pat_memtype_list_init);
1042 #endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */