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 #ifndef clear_user_highpage
  67 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  68 {
  69         void *addr = kmap_atomic(page, KM_USER0);
  70         clear_user_page(addr, vaddr, page);
  71         kunmap_atomic(addr, KM_USER0);
  72 }
  73 #endif
  74
  75 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  76 /**
  77  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
  78  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
  79  * @vma: The VMA the page is to be allocated for
  80  * @vaddr: The virtual address the page will be inserted into
  81  *
  82  * This function will allocate a page for a VMA but the caller is expected
  83  * to specify via movableflags whether the page will be movable in the
  84  * future or not
  85  *
  86  * An architecture may override this function by defining
  87  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
  88  * implementation.
  89  */
  90 static inline struct page *
  91 __alloc_zeroed_user_highpage(gfp_t movableflags,
  92                         struct vm_area_struct *vma,
  93                         unsigned long vaddr)
  94 {
  95         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
  96                         vma, vaddr);
  97
  98         if (page)
  99                 clear_user_highpage(page, vaddr);
 100
 101         return page;
 102 }
 103 #endif
 104
 105 /**
 106  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 107  * @vma: The VMA the page is to be allocated for
 108  * @vaddr: The virtual address the page will be inserted into
 109  *
 110  * This function will allocate a page for a VMA that the caller knows will
 111  * be able to migrate in the future using move_pages() or reclaimed
 112  */
 113 static inline struct page *
 114 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 115                                         unsigned long vaddr)
 116 {
 117         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 118 }
 119
 120 static inline void clear_highpage(struct page *page)
 121 {
 122         void *kaddr = kmap_atomic(page, KM_USER0);
 123         clear_page(kaddr);
 124         kunmap_atomic(kaddr, KM_USER0);
 125 }
 126
 127 static inline void zero_user_segments(struct page *page,
 128         unsigned start1, unsigned end1,
 129         unsigned start2, unsigned end2)
 130 {
 131         void *kaddr = kmap_atomic(page, KM_USER0);
 132
 133         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 134
 135         if (end1 > start1)
 136                 memset(kaddr + start1, 0, end1 - start1);
 137
 138         if (end2 > start2)
 139                 memset(kaddr + start2, 0, end2 - start2);
 140
 141         kunmap_atomic(kaddr, KM_USER0);
 142         flush_dcache_page(page);
 143 }
 144
 145 static inline void zero_user_segment(struct page *page,
 146         unsigned start, unsigned end)
 147 {
 148         zero_user_segments(page, start, end, 0, 0);
 149 }
 150
 151 static inline void zero_user(struct page *page,
 152         unsigned start, unsigned size)
 153 {
 154         zero_user_segments(page, start, start + size, 0, 0);
 155 }
 156
 157 static inline void __deprecated memclear_highpage_flush(struct page *page,
 158                         unsigned int offset, unsigned int size)
 159 {
 160         zero_user(page, offset, size);
 161 }
 162
 163 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 164
 165 static inline void copy_user_highpage(struct page *to, struct page *from,
 166         unsigned long vaddr, struct vm_area_struct *vma)
 167 {
 168         char *vfrom, *vto;
 169
 170         vfrom = kmap_atomic(from, KM_USER0);
 171         vto = kmap_atomic(to, KM_USER1);
 172         copy_user_page(vto, vfrom, vaddr, to);
 173         kunmap_atomic(vfrom, KM_USER0);
 174         kunmap_atomic(vto, KM_USER1);
 175 }
 176
 177 #endif
 178
 179 static inline void copy_highpage(struct page *to, struct page *from)
 180 {
 181         char *vfrom, *vto;
 182
 183         vfrom = kmap_atomic(from, KM_USER0);
 184         vto = kmap_atomic(to, KM_USER1);
 185         copy_page(vto, vfrom);
 186         kunmap_atomic(vfrom, KM_USER0);
 187         kunmap_atomic(vto, KM_USER1);
 188 }
 189
 190 #endif /* _LINUX_HIGHMEM_H */