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1 | /* |
2 | * highmem.h: virtual kernel memory mappings for high memory | |
3 | * | |
4 | * PowerPC version, stolen from the i386 version. | |
5 | * | |
6 | * Used in CONFIG_HIGHMEM systems for memory pages which | |
7 | * are not addressable by direct kernel virtual addresses. | |
8 | * | |
9 | * Copyright (C) 1999 Gerhard Wichert, Siemens AG | |
10 | * Gerhard.Wichert@pdb.siemens.de | |
11 | * | |
12 | * | |
13 | * Redesigned the x86 32-bit VM architecture to deal with | |
14 | * up to 16 Terrabyte physical memory. With current x86 CPUs | |
15 | * we now support up to 64 Gigabytes physical RAM. | |
16 | * | |
17 | * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> | |
18 | */ | |
19 | ||
20 | #ifndef _ASM_HIGHMEM_H | |
21 | #define _ASM_HIGHMEM_H | |
22 | ||
23 | #ifdef __KERNEL__ | |
24 | ||
25 | #include <linux/init.h> | |
26 | #include <linux/interrupt.h> | |
27 | #include <asm/kmap_types.h> | |
28 | #include <asm/tlbflush.h> | |
29 | #include <asm/page.h> | |
2c419bde | 30 | #include <asm/fixmap.h> |
33d71d26 KG |
31 | |
32 | extern pte_t *kmap_pte; | |
33 | extern pgprot_t kmap_prot; | |
34 | extern pte_t *pkmap_page_table; | |
35 | ||
36 | /* | |
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 | |
39 | * chunk of RAM. | |
40 | */ | |
33d71d26 KG |
41 | #define LAST_PKMAP (1 << PTE_SHIFT) |
42 | #define LAST_PKMAP_MASK (LAST_PKMAP-1) | |
2c419bde | 43 | #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK) |
33d71d26 KG |
44 | #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) |
45 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
46 | ||
33d71d26 KG |
47 | extern void *kmap_high(struct page *page); |
48 | extern void kunmap_high(struct page *page); | |
49 | ||
50 | static inline void *kmap(struct page *page) | |
51 | { | |
52 | might_sleep(); | |
53 | if (!PageHighMem(page)) | |
54 | return page_address(page); | |
55 | return kmap_high(page); | |
56 | } | |
57 | ||
58 | static inline void kunmap(struct page *page) | |
59 | { | |
60 | BUG_ON(in_interrupt()); | |
61 | if (!PageHighMem(page)) | |
62 | return; | |
63 | kunmap_high(page); | |
64 | } | |
65 | ||
66 | /* | |
67 | * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap | |
68 | * gives a more generic (and caching) interface. But kmap_atomic can | |
69 | * be used in IRQ contexts, so in some (very limited) cases we need | |
70 | * it. | |
71 | */ | |
2c419bde | 72 | static inline void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) |
33d71d26 KG |
73 | { |
74 | unsigned int idx; | |
75 | unsigned long vaddr; | |
76 | ||
77 | /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ | |
78 | pagefault_disable(); | |
79 | if (!PageHighMem(page)) | |
80 | return page_address(page); | |
81 | ||
82 | idx = type + KM_TYPE_NR*smp_processor_id(); | |
2c419bde KG |
83 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
84 | #ifdef CONFIG_DEBUG_HIGHMEM | |
85 | BUG_ON(!pte_none(*(kmap_pte-idx))); | |
33d71d26 | 86 | #endif |
9bf2b5cd | 87 | __set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot)); |
33d71d26 KG |
88 | flush_tlb_page(NULL, vaddr); |
89 | ||
90 | return (void*) vaddr; | |
91 | } | |
92 | ||
2c419bde KG |
93 | static inline void *kmap_atomic(struct page *page, enum km_type type) |
94 | { | |
95 | return kmap_atomic_prot(page, type, kmap_prot); | |
96 | } | |
97 | ||
33d71d26 KG |
98 | static inline void kunmap_atomic(void *kvaddr, enum km_type type) |
99 | { | |
2c419bde | 100 | #ifdef CONFIG_DEBUG_HIGHMEM |
33d71d26 | 101 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; |
2c419bde | 102 | enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); |
33d71d26 | 103 | |
2c419bde | 104 | if (vaddr < __fix_to_virt(FIX_KMAP_END)) { |
33d71d26 KG |
105 | pagefault_enable(); |
106 | return; | |
107 | } | |
108 | ||
2c419bde | 109 | BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); |
33d71d26 KG |
110 | |
111 | /* | |
112 | * force other mappings to Oops if they'll try to access | |
113 | * this pte without first remap it | |
114 | */ | |
2c419bde | 115 | pte_clear(&init_mm, vaddr, kmap_pte-idx); |
33d71d26 KG |
116 | flush_tlb_page(NULL, vaddr); |
117 | #endif | |
118 | pagefault_enable(); | |
119 | } | |
120 | ||
121 | static inline struct page *kmap_atomic_to_page(void *ptr) | |
122 | { | |
123 | unsigned long idx, vaddr = (unsigned long) ptr; | |
2c419bde | 124 | pte_t *pte; |
33d71d26 | 125 | |
2c419bde | 126 | if (vaddr < FIXADDR_START) |
33d71d26 KG |
127 | return virt_to_page(ptr); |
128 | ||
2c419bde KG |
129 | idx = virt_to_fix(vaddr); |
130 | pte = kmap_pte - (idx - FIX_KMAP_BEGIN); | |
131 | return pte_page(*pte); | |
33d71d26 KG |
132 | } |
133 | ||
134 | #define flush_cache_kmaps() flush_cache_all() | |
135 | ||
136 | #endif /* __KERNEL__ */ | |
137 | ||
138 | #endif /* _ASM_HIGHMEM_H */ |