2 * highmem.h: virtual kernel memory mappings for high memory
4 * Used in CONFIG_HIGHMEM systems for memory pages which
5 * are not addressable by direct kernel virtual addresses.
7 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
8 * Gerhard.Wichert@pdb.siemens.de
11 * Redesigned the x86 32-bit VM architecture to deal with
12 * up to 16 Terabyte physical memory. With current x86 CPUs
13 * we now support up to 64 Gigabytes physical RAM.
15 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
17 #ifndef _ASM_HIGHMEM_H
18 #define _ASM_HIGHMEM_H
22 #include <linux/interrupt.h>
23 #include <linux/uaccess.h>
24 #include <asm/kmap_types.h>
26 /* undef for production */
27 #define HIGHMEM_DEBUG 1
29 /* declarations for highmem.c */
30 extern unsigned long highstart_pfn
, highend_pfn
;
32 extern pte_t
*pkmap_page_table
;
35 * Right now we initialize only a single pte table. It can be extended
36 * easily, subsequent pte tables have to be allocated in one physical
39 #define LAST_PKMAP 1024
40 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
41 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
42 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
44 extern void * kmap_high(struct page
*page
);
45 extern void kunmap_high(struct page
*page
);
47 extern void *kmap(struct page
*page
);
48 extern void kunmap(struct page
*page
);
49 extern void *kmap_atomic(struct page
*page
);
50 extern void __kunmap_atomic(void *kvaddr
);
51 extern void *kmap_atomic_pfn(unsigned long pfn
);
52 extern struct page
*kmap_atomic_to_page(void *ptr
);
54 #define flush_cache_kmaps() flush_cache_all()
56 extern void kmap_init(void);
58 #define kmap_prot PAGE_KERNEL
60 #endif /* __KERNEL__ */
62 #endif /* _ASM_HIGHMEM_H */