1 /*
2 * highmem.h: virtual kernel memory mappings for high memory
3 *
4 * Used in CONFIG_HIGHMEM systems for memory pages which
5 * are not addressable by direct kernel virtual addresses.
6 *
7 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
8 * Gerhard.Wichert@pdb.siemens.de
9 *
10 *
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.
14 *
15 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
16 */
17
18 #ifndef _ASM_HIGHMEM_H
19 #define _ASM_HIGHMEM_H
20
21 #ifdef __KERNEL__
22
23 #include <linux/config.h>
24 #include <linux/interrupt.h>
25 #include <linux/threads.h>
26 #include <asm/kmap_types.h>
27 #include <asm/tlbflush.h>
28
29 /* declarations for highmem.c */
30 extern unsigned long highstart_pfn, highend_pfn;
31
32 extern pte_t *kmap_pte;
33 extern pgprot_t kmap_prot;
34 extern pte_t *pkmap_page_table;
35
36 extern void kmap_init(void);
37
38 /*
39 * Right now we initialize only a single pte table. It can be extended
40 * easily, subsequent pte tables have to be allocated in one physical
41 * chunk of RAM.
42 */
43 #ifdef CONFIG_X86_PAE
44 #define LAST_PKMAP 512
45 #else
46 #define LAST_PKMAP 1024
47 #endif
48 /*
49 * Ordering is:
50 *
51 * FIXADDR_TOP
52 * fixed_addresses
53 * FIXADDR_START
54 * temp fixed addresses
55 * FIXADDR_BOOT_START
56 * Persistent kmap area
57 * PKMAP_BASE
58 * VMALLOC_END
59 * Vmalloc area
60 * VMALLOC_START
61 * high_memory
62 */
63 #define PKMAP_BASE ( (FIXADDR_BOOT_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK )
64 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
65 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
66 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
67
68 extern void * FASTCALL(kmap_high(struct page *page));
69 extern void FASTCALL(kunmap_high(struct page *page));
70
71 void *kmap(struct page *page);
72 void kunmap(struct page *page);
73 void *kmap_atomic(struct page *page, enum km_type type);
74 void kunmap_atomic(void *kvaddr, enum km_type type);
75 struct page *kmap_atomic_to_page(void *ptr);
76
77 #define flush_cache_kmaps() do { } while (0)
78
79 #endif /* __KERNEL__ */
80
81 #endif /* _ASM_HIGHMEM_H */
82
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