1 #ifndef _LINUX_HIGHMEM_H
2 #define _LINUX_HIGHMEM_H
4 #include <linux/config.h>
8 #include <asm/cacheflush.h>
12 extern struct page *highmem_start_page;
14 #include <asm/highmem.h>
16 /* declarations for linux/mm/highmem.c */
17 unsigned int nr_free_highpages(void);
19 #else /* CONFIG_HIGHMEM */
21 static inline unsigned int nr_free_highpages(void) { return 0; }
23 static inline void *kmap(struct page *page)
26 return page_address(page);
29 #define kunmap(page) do { (void) (page); } while (0)
31 #define kmap_atomic(page, idx) page_address(page)
32 #define kunmap_atomic(addr, idx) do { } while (0)
33 #define kmap_atomic_to_page(ptr) virt_to_page(ptr)
35 #endif /* CONFIG_HIGHMEM */
37 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
38 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
40 void *addr = kmap_atomic(page, KM_USER0);
41 clear_user_page(addr, vaddr, page);
42 kunmap_atomic(addr, KM_USER0);
45 static inline void clear_highpage(struct page *page)
47 void *kaddr = kmap_atomic(page, KM_USER0);
49 kunmap_atomic(kaddr, KM_USER0);
53 * Same but also flushes aliased cache contents to RAM.
55 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
59 BUG_ON(offset + size > PAGE_SIZE);
61 kaddr = kmap_atomic(page, KM_USER0);
62 memset((char *)kaddr + offset, 0, size);
63 flush_dcache_page(page);
64 kunmap_atomic(kaddr, KM_USER0);
67 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
71 vfrom = kmap_atomic(from, KM_USER0);
72 vto = kmap_atomic(to, KM_USER1);
73 copy_user_page(vto, vfrom, vaddr, to);
74 kunmap_atomic(vfrom, KM_USER0);
75 kunmap_atomic(vto, KM_USER1);
78 static inline void copy_highpage(struct page *to, struct page *from)
82 vfrom = kmap_atomic(from, KM_USER0);
83 vto = kmap_atomic(to, KM_USER1);
84 copy_page(vto, vfrom);
85 kunmap_atomic(vfrom, KM_USER0);
86 kunmap_atomic(vto, KM_USER1);
89 #endif /* _LINUX_HIGHMEM_H */