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 */
  66static 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 */
  88static 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 */
 111static inline struct page *
 112alloc_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
 118static 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
 125static 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
 143static 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
 149static 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
 155static 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
 163static 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
 177static 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 */
 189
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