LXR linux/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
   7#include <asm/cacheflush.h>
   8
   9#ifndef ARCH_HAS_FLUSH_ANON_PAGE
  10static inline void flush_anon_page(struct page *page, unsigned long vmaddr)
  11{
  12}
  13#endif
  14
  15#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  16static inline void flush_kernel_dcache_page(struct page *page)
  17{
  18}
  19#endif
  20
  21#ifdef CONFIG_HIGHMEM
  22
  23#include <asm/highmem.h>
  24
  25/* declarations for linux/mm/highmem.c */
  26unsigned int nr_free_highpages(void);
  27
  28#else /* CONFIG_HIGHMEM */
  29
  30static inline unsigned int nr_free_highpages(void) { return 0; }
  31
  32static inline void *kmap(struct page *page)
  33{
  34        might_sleep();
  35        return page_address(page);
  36}
  37
  38#define kunmap(page) do { (void) (page); } while (0)
  39
  40#define kmap_atomic(page, idx)          page_address(page)
  41#define kunmap_atomic(addr, idx)        do { } while (0)
  42#define kmap_atomic_pfn(pfn, idx)       page_address(pfn_to_page(pfn))
  43#define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  44
  45#endif /* CONFIG_HIGHMEM */
  46
  47/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  48static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  49{
  50        void *addr = kmap_atomic(page, KM_USER0);
  51        clear_user_page(addr, vaddr, page);
  52        kunmap_atomic(addr, KM_USER0);
  53        /* Make sure this page is cleared on other CPU's too before using it */
  54        smp_wmb();
  55}
  56
  57#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  58static inline struct page *
  59alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
  60{
  61        struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
  62
  63        if (page)
  64                clear_user_highpage(page, vaddr);
  65
  66        return page;
  67}
  68#endif
  69
  70static inline void clear_highpage(struct page *page)
  71{
  72        void *kaddr = kmap_atomic(page, KM_USER0);
  73        clear_page(kaddr);
  74        kunmap_atomic(kaddr, KM_USER0);
  75}
  76
  77/*
  78 * Same but also flushes aliased cache contents to RAM.
  79 */
  80static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  81{
  82        void *kaddr;
  83
  84        BUG_ON(offset + size > PAGE_SIZE);
  85
  86        kaddr = kmap_atomic(page, KM_USER0);
  87        memset((char *)kaddr + offset, 0, size);
  88        flush_dcache_page(page);
  89        kunmap_atomic(kaddr, KM_USER0);
  90}
  91
  92static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
  93{
  94        char *vfrom, *vto;
  95
  96        vfrom = kmap_atomic(from, KM_USER0);
  97        vto = kmap_atomic(to, KM_USER1);
  98        copy_user_page(vto, vfrom, vaddr, to);
  99        kunmap_atomic(vfrom, KM_USER0);
 100        kunmap_atomic(vto, KM_USER1);
 101        /* Make sure this page is cleared on other CPU's too before using it */
 102        smp_wmb();
 103}
 104
 105static inline void copy_highpage(struct page *to, struct page *from)
 106{
 107        char *vfrom, *vto;
 108
 109        vfrom = kmap_atomic(from, KM_USER0);
 110        vto = kmap_atomic(to, KM_USER1);
 111        copy_page(vto, vfrom);
 112        kunmap_atomic(vfrom, KM_USER0);
 113        kunmap_atomic(vto, KM_USER1);
 114}
 115
 116#endif /* _LINUX_HIGHMEM_H */
 117