include/linux/highmem.h

   1 #ifndef _LINUX_HIGHMEM_H
   2 #define _LINUX_HIGHMEM_H
   3
   4 #include <linux/fs.h>
   5 #include <linux/mm.h>
   6 #include <linux/uaccess.h>
   7
   8 #include <asm/cacheflush.h>
   9
  10 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  11 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  12 {
  13 }
  14 #endif
  15
  16 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  17 static inline void flush_kernel_dcache_page(struct page *page)
  18 {
  19 }
  20 #endif
  21
  22 #include <asm/kmap_types.h>
  23
  24 #if defined(CONFIG_DEBUG_HIGHMEM) && defined(CONFIG_TRACE_IRQFLAGS_SUPPORT)
  25
  26 void debug_kmap_atomic(enum km_type type);
  27
  28 #else
  29
  30 static inline void debug_kmap_atomic(enum km_type type)
  31 {
  32 }
  33
  34 #endif
  35
  36 #ifdef CONFIG_HIGHMEM
  37 #include <asm/highmem.h>
  38
  39 /* declarations for linux/mm/highmem.c */
  40 unsigned int nr_free_highpages(void);
  41 extern unsigned long totalhigh_pages;
  42
  43 void kmap_flush_unused(void);
  44
  45 #else /* CONFIG_HIGHMEM */
  46
  47 static inline unsigned int nr_free_highpages(void) { return 0; }
  48
  49 #define totalhigh_pages 0
  50
  51 #ifndef ARCH_HAS_KMAP
  52 static inline void *kmap(struct page *page)
  53 {
  54         might_sleep();
  55         return page_address(page);
  56 }
  57
  58 #define kunmap(page) do { (void) (page); } while (0)
  59
  60 static inline void *kmap_atomic(struct page *page, enum km_type idx)
  61 {
  62         pagefault_disable();
  63         return page_address(page);
  64 }
  65 #define kmap_atomic_prot(page, idx, prot)       kmap_atomic(page, idx)
  66
  67 #define kunmap_atomic(addr, idx)        do { pagefault_enable(); } while (0)
  68 #define kmap_atomic_pfn(pfn, idx)       kmap_atomic(pfn_to_page(pfn), (idx))
  69 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  70
  71 #define kmap_flush_unused()     do {} while(0)
  72 #endif
  73
  74 #endif /* CONFIG_HIGHMEM */
  75
  76 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  77 #ifndef clear_user_highpage
  78 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  79 {
  80         void *addr = kmap_atomic(page, KM_USER0);
  81         clear_user_page(addr, vaddr, page);
  82         kunmap_atomic(addr, KM_USER0);
  83 }
  84 #endif
  85
  86 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  87 /**
  88  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
  89  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
  90  * @vma: The VMA the page is to be allocated for
  91  * @vaddr: The virtual address the page will be inserted into
  92  *
  93  * This function will allocate a page for a VMA but the caller is expected
  94  * to specify via movableflags whether the page will be movable in the
  95  * future or not
  96  *
  97  * An architecture may override this function by defining
  98  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
  99  * implementation.
 100  */
 101 static inline struct page *
 102 __alloc_zeroed_user_highpage(gfp_t movableflags,
 103                         struct vm_area_struct *vma,
 104                         unsigned long vaddr)
 105 {
 106         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 107                         vma, vaddr);
 108
 109         if (page)
 110                 clear_user_highpage(page, vaddr);
 111
 112         return page;
 113 }
 114 #endif
 115
 116 /**
 117  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 118  * @vma: The VMA the page is to be allocated for
 119  * @vaddr: The virtual address the page will be inserted into
 120  *
 121  * This function will allocate a page for a VMA that the caller knows will
 122  * be able to migrate in the future using move_pages() or reclaimed
 123  */
 124 static inline struct page *
 125 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 126                                         unsigned long vaddr)
 127 {
 128         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 129 }
 130
 131 static inline void clear_highpage(struct page *page)
 132 {
 133         void *kaddr = kmap_atomic(page, KM_USER0);
 134         clear_page(kaddr);
 135         kunmap_atomic(kaddr, KM_USER0);
 136 }
 137
 138 static inline void zero_user_segments(struct page *page,
 139         unsigned start1, unsigned end1,
 140         unsigned start2, unsigned end2)
 141 {
 142         void *kaddr = kmap_atomic(page, KM_USER0);
 143
 144         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 145
 146         if (end1 > start1)
 147                 memset(kaddr + start1, 0, end1 - start1);
 148
 149         if (end2 > start2)
 150                 memset(kaddr + start2, 0, end2 - start2);
 151
 152         kunmap_atomic(kaddr, KM_USER0);
 153         flush_dcache_page(page);
 154 }
 155
 156 static inline void zero_user_segment(struct page *page,
 157         unsigned start, unsigned end)
 158 {
 159         zero_user_segments(page, start, end, 0, 0);
 160 }
 161
 162 static inline void zero_user(struct page *page,
 163         unsigned start, unsigned size)
 164 {
 165         zero_user_segments(page, start, start + size, 0, 0);
 166 }
 167
 168 static inline void __deprecated memclear_highpage_flush(struct page *page,
 169                         unsigned int offset, unsigned int size)
 170 {
 171         zero_user(page, offset, size);
 172 }
 173
 174 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 175
 176 static inline void copy_user_highpage(struct page *to, struct page *from,
 177         unsigned long vaddr, struct vm_area_struct *vma)
 178 {
 179         char *vfrom, *vto;
 180
 181         vfrom = kmap_atomic(from, KM_USER0);
 182         vto = kmap_atomic(to, KM_USER1);
 183         copy_user_page(vto, vfrom, vaddr, to);
 184         kunmap_atomic(vfrom, KM_USER0);
 185         kunmap_atomic(vto, KM_USER1);
 186 }
 187
 188 #endif
 189
 190 static inline void copy_highpage(struct page *to, struct page *from)
 191 {
 192         char *vfrom, *vto;
 193
 194         vfrom = kmap_atomic(from, KM_USER0);
 195         vto = kmap_atomic(to, KM_USER1);
 196         copy_page(vto, vfrom);
 197         kunmap_atomic(vfrom, KM_USER0);
 198         kunmap_atomic(vto, KM_USER1);
 199 }
 200
 201 #endif /* _LINUX_HIGHMEM_H */