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1da177e4 LT |
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 | #ifndef _ASM_HIGHMEM_H | |
18 | #define _ASM_HIGHMEM_H | |
19 | ||
20 | #ifdef __KERNEL__ | |
21 | ||
1da177e4 LT |
22 | #include <linux/init.h> |
23 | #include <linux/interrupt.h> | |
ad76fb6b | 24 | #include <linux/uaccess.h> |
1da177e4 LT |
25 | #include <asm/kmap_types.h> |
26 | ||
27 | /* undef for production */ | |
28 | #define HIGHMEM_DEBUG 1 | |
29 | ||
30 | /* declarations for highmem.c */ | |
31 | extern unsigned long highstart_pfn, highend_pfn; | |
32 | ||
33 | extern pte_t *kmap_pte; | |
34 | extern pgprot_t kmap_prot; | |
35 | extern pte_t *pkmap_page_table; | |
36 | ||
37 | /* | |
38 | * Right now we initialize only a single pte table. It can be extended | |
39 | * easily, subsequent pte tables have to be allocated in one physical | |
40 | * chunk of RAM. | |
41 | */ | |
42 | #define PKMAP_BASE (0xfe000000UL) | |
43 | #define LAST_PKMAP 1024 | |
44 | #define LAST_PKMAP_MASK (LAST_PKMAP-1) | |
45 | #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) | |
46 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
47 | ||
48 | extern void * kmap_high(struct page *page); | |
49 | extern void kunmap_high(struct page *page); | |
50 | ||
51 | /* | |
52 | * CONFIG_LIMITED_DMA is for systems with DMA limitations such as Momentum's | |
53 | * Jaguar ATX. This option exploits the highmem code in the kernel so is | |
54 | * always enabled together with CONFIG_HIGHMEM but at this time doesn't | |
55 | * actually add highmem functionality. | |
56 | */ | |
57 | ||
58 | #ifdef CONFIG_LIMITED_DMA | |
59 | ||
60 | /* | |
61 | * These are the default functions for the no-highmem case from | |
62 | * <linux/highmem.h> | |
63 | */ | |
64 | static inline void *kmap(struct page *page) | |
65 | { | |
66 | might_sleep(); | |
67 | return page_address(page); | |
68 | } | |
69 | ||
70 | #define kunmap(page) do { (void) (page); } while (0) | |
71 | ||
72 | static inline void *kmap_atomic(struct page *page, enum km_type type) | |
73 | { | |
ad76fb6b | 74 | pagefault_disable(); |
1da177e4 LT |
75 | return page_address(page); |
76 | } | |
77 | ||
ad76fb6b PZ |
78 | static inline void kunmap_atomic(void *kvaddr, enum km_type type) |
79 | { | |
80 | pagefault_enable(); | |
81 | } | |
82 | ||
83 | #define kmap_atomic_pfn(pfn, idx) kmap_atomic(pfn_to_page(pfn), (idx)) | |
1da177e4 LT |
84 | |
85 | #define kmap_atomic_to_page(ptr) virt_to_page(ptr) | |
86 | ||
87 | #define flush_cache_kmaps() do { } while (0) | |
88 | ||
89 | #else /* LIMITED_DMA */ | |
90 | ||
91 | extern void *__kmap(struct page *page); | |
92 | extern void __kunmap(struct page *page); | |
93 | extern void *__kmap_atomic(struct page *page, enum km_type type); | |
94 | extern void __kunmap_atomic(void *kvaddr, enum km_type type); | |
60080265 | 95 | extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); |
1da177e4 LT |
96 | extern struct page *__kmap_atomic_to_page(void *ptr); |
97 | ||
98 | #define kmap __kmap | |
99 | #define kunmap __kunmap | |
100 | #define kmap_atomic __kmap_atomic | |
101 | #define kunmap_atomic __kunmap_atomic | |
102 | #define kmap_atomic_to_page __kmap_atomic_to_page | |
103 | ||
104 | #define flush_cache_kmaps() flush_cache_all() | |
105 | ||
106 | #endif /* LIMITED_DMA */ | |
107 | ||
108 | #endif /* __KERNEL__ */ | |
109 | ||
110 | #endif /* _ASM_HIGHMEM_H */ |