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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 | */ | |
ca9153a3 IY |
41 | /* |
42 | * We use one full pte table with 4K pages. And with 16K/64K pages pte | |
43 | * table covers enough memory (32MB and 512MB resp.) that both FIXMAP | |
44 | * and PKMAP can be placed in single pte table. We use 1024 pages for | |
45 | * PKMAP in case of 16K/64K pages. | |
46 | */ | |
47 | #ifdef CONFIG_PPC_4K_PAGES | |
48 | #define PKMAP_ORDER PTE_SHIFT | |
49 | #else | |
50 | #define PKMAP_ORDER 10 | |
51 | #endif | |
52 | #define LAST_PKMAP (1 << PKMAP_ORDER) | |
53 | #ifndef CONFIG_PPC_4K_PAGES | |
54 | #define PKMAP_BASE (FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) | |
55 | #else | |
2c419bde | 56 | #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK) |
ca9153a3 IY |
57 | #endif |
58 | #define LAST_PKMAP_MASK (LAST_PKMAP-1) | |
33d71d26 KG |
59 | #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) |
60 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
61 | ||
33d71d26 KG |
62 | extern void *kmap_high(struct page *page); |
63 | extern void kunmap_high(struct page *page); | |
64 | ||
65 | static inline void *kmap(struct page *page) | |
66 | { | |
67 | might_sleep(); | |
68 | if (!PageHighMem(page)) | |
69 | return page_address(page); | |
70 | return kmap_high(page); | |
71 | } | |
72 | ||
73 | static inline void kunmap(struct page *page) | |
74 | { | |
75 | BUG_ON(in_interrupt()); | |
76 | if (!PageHighMem(page)) | |
77 | return; | |
78 | kunmap_high(page); | |
79 | } | |
80 | ||
81 | /* | |
82 | * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap | |
83 | * gives a more generic (and caching) interface. But kmap_atomic can | |
84 | * be used in IRQ contexts, so in some (very limited) cases we need | |
85 | * it. | |
86 | */ | |
2c419bde | 87 | static inline void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) |
33d71d26 KG |
88 | { |
89 | unsigned int idx; | |
90 | unsigned long vaddr; | |
91 | ||
92 | /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ | |
93 | pagefault_disable(); | |
94 | if (!PageHighMem(page)) | |
95 | return page_address(page); | |
96 | ||
97 | idx = type + KM_TYPE_NR*smp_processor_id(); | |
2c419bde KG |
98 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
99 | #ifdef CONFIG_DEBUG_HIGHMEM | |
100 | BUG_ON(!pte_none(*(kmap_pte-idx))); | |
33d71d26 | 101 | #endif |
8d30c14c | 102 | __set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot), 1); |
f048aace | 103 | local_flush_tlb_page(NULL, vaddr); |
33d71d26 KG |
104 | |
105 | return (void*) vaddr; | |
106 | } | |
107 | ||
2c419bde KG |
108 | static inline void *kmap_atomic(struct page *page, enum km_type type) |
109 | { | |
110 | return kmap_atomic_prot(page, type, kmap_prot); | |
111 | } | |
112 | ||
33d71d26 KG |
113 | static inline void kunmap_atomic(void *kvaddr, enum km_type type) |
114 | { | |
2c419bde | 115 | #ifdef CONFIG_DEBUG_HIGHMEM |
33d71d26 | 116 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; |
2c419bde | 117 | enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); |
33d71d26 | 118 | |
2c419bde | 119 | if (vaddr < __fix_to_virt(FIX_KMAP_END)) { |
33d71d26 KG |
120 | pagefault_enable(); |
121 | return; | |
122 | } | |
123 | ||
2c419bde | 124 | BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); |
33d71d26 KG |
125 | |
126 | /* | |
127 | * force other mappings to Oops if they'll try to access | |
128 | * this pte without first remap it | |
129 | */ | |
2c419bde | 130 | pte_clear(&init_mm, vaddr, kmap_pte-idx); |
f048aace | 131 | local_flush_tlb_page(NULL, vaddr); |
33d71d26 KG |
132 | #endif |
133 | pagefault_enable(); | |
134 | } | |
135 | ||
136 | static inline struct page *kmap_atomic_to_page(void *ptr) | |
137 | { | |
138 | unsigned long idx, vaddr = (unsigned long) ptr; | |
2c419bde | 139 | pte_t *pte; |
33d71d26 | 140 | |
2c419bde | 141 | if (vaddr < FIXADDR_START) |
33d71d26 KG |
142 | return virt_to_page(ptr); |
143 | ||
2c419bde KG |
144 | idx = virt_to_fix(vaddr); |
145 | pte = kmap_pte - (idx - FIX_KMAP_BEGIN); | |
146 | return pte_page(*pte); | |
33d71d26 KG |
147 | } |
148 | ||
149 | #define flush_cache_kmaps() flush_cache_all() | |
150 | ||
151 | #endif /* __KERNEL__ */ | |
152 | ||
153 | #endif /* _ASM_HIGHMEM_H */ |