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d73cd428 NP |
1 | /* |
2 | * arch/arm/mm/highmem.c -- ARM highmem support | |
3 | * | |
4 | * Author: Nicolas Pitre | |
5 | * Created: september 8, 2008 | |
6 | * Copyright: Marvell Semiconductors Inc. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/highmem.h> | |
15 | #include <linux/interrupt.h> | |
16 | #include <asm/fixmap.h> | |
17 | #include <asm/cacheflush.h> | |
18 | #include <asm/tlbflush.h> | |
19 | #include "mm.h" | |
20 | ||
21 | void *kmap(struct page *page) | |
22 | { | |
23 | might_sleep(); | |
24 | if (!PageHighMem(page)) | |
25 | return page_address(page); | |
26 | return kmap_high(page); | |
27 | } | |
28 | EXPORT_SYMBOL(kmap); | |
29 | ||
30 | void kunmap(struct page *page) | |
31 | { | |
32 | BUG_ON(in_interrupt()); | |
33 | if (!PageHighMem(page)) | |
34 | return; | |
35 | kunmap_high(page); | |
36 | } | |
37 | EXPORT_SYMBOL(kunmap); | |
38 | ||
39 | void *kmap_atomic(struct page *page, enum km_type type) | |
40 | { | |
41 | unsigned int idx; | |
42 | unsigned long vaddr; | |
43 | ||
44 | pagefault_disable(); | |
45 | if (!PageHighMem(page)) | |
46 | return page_address(page); | |
47 | ||
48 | idx = type + KM_TYPE_NR * smp_processor_id(); | |
49 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
50 | #ifdef CONFIG_DEBUG_HIGHMEM | |
51 | /* | |
52 | * With debugging enabled, kunmap_atomic forces that entry to 0. | |
53 | * Make sure it was indeed properly unmapped. | |
54 | */ | |
55 | BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); | |
56 | #endif | |
57 | set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0); | |
58 | /* | |
59 | * When debugging is off, kunmap_atomic leaves the previous mapping | |
60 | * in place, so this TLB flush ensures the TLB is updated with the | |
61 | * new mapping. | |
62 | */ | |
63 | local_flush_tlb_kernel_page(vaddr); | |
64 | ||
65 | return (void *)vaddr; | |
66 | } | |
67 | EXPORT_SYMBOL(kmap_atomic); | |
68 | ||
69 | void kunmap_atomic(void *kvaddr, enum km_type type) | |
70 | { | |
71 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; | |
72 | unsigned int idx = type + KM_TYPE_NR * smp_processor_id(); | |
73 | ||
74 | if (kvaddr >= (void *)FIXADDR_START) { | |
75 | __cpuc_flush_dcache_page((void *)vaddr); | |
76 | #ifdef CONFIG_DEBUG_HIGHMEM | |
77 | BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); | |
78 | set_pte_ext(TOP_PTE(vaddr), __pte(0), 0); | |
79 | local_flush_tlb_kernel_page(vaddr); | |
80 | #else | |
81 | (void) idx; /* to kill a warning */ | |
82 | #endif | |
83 | } | |
84 | pagefault_enable(); | |
85 | } | |
86 | EXPORT_SYMBOL(kunmap_atomic); | |
87 | ||
88 | void *kmap_atomic_pfn(unsigned long pfn, enum km_type type) | |
89 | { | |
90 | unsigned int idx; | |
91 | unsigned long vaddr; | |
92 | ||
93 | pagefault_disable(); | |
94 | ||
95 | idx = type + KM_TYPE_NR * smp_processor_id(); | |
96 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
97 | #ifdef CONFIG_DEBUG_HIGHMEM | |
98 | BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); | |
99 | #endif | |
100 | set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0); | |
101 | local_flush_tlb_kernel_page(vaddr); | |
102 | ||
103 | return (void *)vaddr; | |
104 | } | |
105 | ||
106 | struct page *kmap_atomic_to_page(const void *ptr) | |
107 | { | |
108 | unsigned long vaddr = (unsigned long)ptr; | |
109 | pte_t *pte; | |
110 | ||
111 | if (vaddr < FIXADDR_START) | |
112 | return virt_to_page(ptr); | |
113 | ||
114 | pte = TOP_PTE(vaddr); | |
115 | return pte_page(*pte); | |
116 | } |