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