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