1 #ifndef _LINUX_HIGHMEM_H
2 #define _LINUX_HIGHMEM_H
4 #include <linux/config.h>
5 #include <asm/pgalloc.h>
9 extern struct page *highmem_start_page;
11 #include <asm/highmem.h>
13 /* declarations for linux/mm/highmem.c */
14 unsigned int nr_free_highpages(void);
16 extern struct buffer_head *create_bounce(int rw, struct buffer_head * bh_orig);
18 static inline char *bh_kmap(struct buffer_head *bh)
20 return kmap(bh->b_page) + bh_offset(bh);
23 static inline void bh_kunmap(struct buffer_head *bh)
29 * remember to add offset! and never ever reenable interrupts between a
30 * bh_kmap_irq and bh_kunmap_irq!!
32 static inline char *bh_kmap_irq(struct buffer_head *bh, unsigned long *flags)
41 if (!PageHighMem(bh->b_page))
48 addr = (unsigned long) kmap_atomic(bh->b_page, KM_BH_IRQ);
50 if (addr & ~PAGE_MASK)
53 return (char *) addr + bh_offset(bh);
56 static inline void bh_kunmap_irq(char *buffer, unsigned long *flags)
58 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
60 kunmap_atomic((void *) ptr, KM_BH_IRQ);
61 __restore_flags(*flags);
64 #else /* CONFIG_HIGHMEM */
66 static inline unsigned int nr_free_highpages(void) { return 0; }
68 static inline void *kmap(struct page *page) { return page_address(page); }
70 #define kunmap(page) do { } while (0)
72 #define kmap_atomic(page,idx) kmap(page)
73 #define kunmap_atomic(page,idx) kunmap(page)
75 #define bh_kmap(bh) ((bh)->b_data)
76 #define bh_kunmap(bh) do { } while (0)
77 #define bh_kmap_irq(bh, flags) ((bh)->b_data)
78 #define bh_kunmap_irq(bh, flags) do { *(flags) = 0; } while (0)
80 #endif /* CONFIG_HIGHMEM */
82 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
83 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
85 void *addr = kmap_atomic(page, KM_USER0);
86 clear_user_page(addr, vaddr);
87 kunmap_atomic(addr, KM_USER0);
90 static inline void clear_highpage(struct page *page)
92 clear_page(kmap(page));
97 * Same but also flushes aliased cache contents to RAM.
99 static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size)
103 if (offset + size > PAGE_SIZE)
106 memset(kaddr + offset, 0, size);
107 flush_dcache_page(page);
108 flush_page_to_ram(page);
112 static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
116 vfrom = kmap_atomic(from, KM_USER0);
117 vto = kmap_atomic(to, KM_USER1);
118 copy_user_page(vto, vfrom, vaddr);
119 kunmap_atomic(vfrom, KM_USER0);
120 kunmap_atomic(vto, KM_USER1);
123 #endif /* _LINUX_HIGHMEM_H */