include/linux/highmem.h

   1 #ifndef _LINUX_HIGHMEM_H
   2 #define _LINUX_HIGHMEM_H
   3
   4 #include <linux/config.h>
   5 #include <linux/fs.h>
   6 #include <linux/mm.h>
   7
   8 #include <asm/cacheflush.h>
   9
  10 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  11 static inline void flush_anon_page(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
  29 #else /* CONFIG_HIGHMEM */
  30
  31 static inline unsigned int nr_free_highpages(void) { return 0; }
  32
  33 static inline void *kmap(struct page *page)
  34 {
  35         might_sleep();
  36         return page_address(page);
  37 }
  38
  39 #define kunmap(page) do { (void) (page); } while (0)
  40
  41 #define kmap_atomic(page, idx)          page_address(page)
  42 #define kunmap_atomic(addr, idx)        do { } while (0)
  43 #define kmap_atomic_pfn(pfn, idx)       page_address(pfn_to_page(pfn))
  44 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  45
  46 #endif /* CONFIG_HIGHMEM */
  47
  48 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
  49 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
  50 {
  51         void *addr = kmap_atomic(page, KM_USER0);
  52         clear_user_page(addr, vaddr, page);
  53         kunmap_atomic(addr, KM_USER0);
  54         /* Make sure this page is cleared on other CPU's too before using it */
  55         smp_wmb();
  56 }
  57
  58 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
  59 static inline struct page *
  60 alloc_zeroed_user_highpage(struct vm_area_struct *vma, unsigned long vaddr)
  61 {
  62         struct page *page = alloc_page_vma(GFP_HIGHUSER, vma, vaddr);
  63
  64         if (page)
  65                 clear_user_highpage(page, vaddr);
  66
  67         return page;
  68 }
  69 #endif
  70
  71 static inline void clear_highpage(struct page *page)
  72 {
  73         void *kaddr = kmap_atomic(page, KM_USER0);
  74         clear_page(kaddr);
  75         kunmap_atomic(kaddr, KM_USER0);
  76 }
  77
  78 /*
  79  * Same but also flushes aliased cache contents to RAM.
  80  */
  81 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
  82 {
  83         void *kaddr;
  84
  85         BUG_ON(offset + size > PAGE_SIZE);
  86
  87         kaddr = kmap_atomic(page, KM_USER0);
  88         memset((char *)kaddr + offset, 0, size);
  89         flush_dcache_page(page);
  90         kunmap_atomic(kaddr, KM_USER0);
  91 }
  92
  93 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
  94 {
  95         char *vfrom, *vto;
  96
  97         vfrom = kmap_atomic(from, KM_USER0);
  98         vto = kmap_atomic(to, KM_USER1);
  99         copy_user_page(vto, vfrom, vaddr, to);
 100         kunmap_atomic(vfrom, KM_USER0);
 101         kunmap_atomic(vto, KM_USER1);
 102         /* Make sure this page is cleared on other CPU's too before using it */
 103         smp_wmb();
 104 }
 105
 106 static inline void copy_highpage(struct page *to, struct page *from)
 107 {
 108         char *vfrom, *vto;
 109
 110         vfrom = kmap_atomic(from, KM_USER0);
 111         vto = kmap_atomic(to, KM_USER1);
 112         copy_page(vto, vfrom);
 113         kunmap_atomic(vfrom, KM_USER0);
 114         kunmap_atomic(vto, KM_USER1);
 115 }
 116
 117 #endif /* _LINUX_HIGHMEM_H */