Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shaggy...
[linux-2.6] / arch / arm / mm / highmem.c
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 }