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
  10 static inline void flush_anon_page(struct page *page, unsigned long vmaddr)
  11 {
  12 }
  13 #endif
  14
  15 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  16 static 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 */
  26 unsigned int nr_free_highpages(void);
  27
  28 #else /* CONFIG_HIGHMEM */
  29
  30 static inline unsigned int nr_free_highpages(void) { return 0; }
  31
  32 static 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 */
  48 static 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
  58 static inline struct page *
  59 alloc_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
  70 static 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  */
  80 static 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
  92 static 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
 105 static 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 */