linux/include/linux/highmem.h
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   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
  11static 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
  17static 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 */
  27unsigned int nr_free_highpages(void);
  28extern unsigned long totalhigh_pages;
  29
  30void kmap_flush_unused(void);
  31
  32#else /* CONFIG_HIGHMEM */
  33
  34static inline unsigned int nr_free_highpages(void) { return 0; }
  35
  36#define totalhigh_pages 0
  37
  38#ifndef ARCH_HAS_KMAP
  39static 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
  49static 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
  67static 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 */
  90static 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 */
 113static inline struct page *
 114alloc_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
 120static 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
 127static 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
 145static 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
 151static 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
 157static 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
 165static 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
 179static 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 */
 191
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