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>
18 #ifndef _ASM_HIGHMEM_H
19 #define _ASM_HIGHMEM_H
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>
29 /* declarations for highmem.c */
30 extern unsigned long highstart_pfn, highend_pfn;
32 extern pte_t *kmap_pte;
33 extern pgprot_t kmap_prot;
34 extern pte_t *pkmap_page_table;
37 * Right now we initialize only a single pte table. It can be extended
38 * easily, subsequent pte tables have to be allocated in one physical
42 #define LAST_PKMAP 512
44 #define LAST_PKMAP 1024
52 * temp fixed addresses
54 * Persistent kmap area
61 #define PKMAP_BASE ( (FIXADDR_BOOT_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK )
62 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
63 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
64 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
66 extern void * FASTCALL(kmap_high(struct page *page));
67 extern void FASTCALL(kunmap_high(struct page *page));
69 void *kmap(struct page *page);
70 void kunmap(struct page *page);
71 void *kmap_atomic(struct page *page, enum km_type type);
72 void *kmap_atomic_pte(struct page *page, enum km_type type);
73 void kunmap_atomic(void *kvaddr, enum km_type type);
74 void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
75 struct page *kmap_atomic_to_page(void *ptr);
77 #define flush_cache_kmaps() do { } while (0)
79 #endif /* __KERNEL__ */
81 #endif /* _ASM_HIGHMEM_H */