Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / 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         void *kmap;
44
45         pagefault_disable();
46         if (!PageHighMem(page))
47                 return page_address(page);
48
49         debug_kmap_atomic(type);
50
51         kmap = kmap_high_get(page);
52         if (kmap)
53                 return kmap;
54
55         idx = type + KM_TYPE_NR * smp_processor_id();
56         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
57 #ifdef CONFIG_DEBUG_HIGHMEM
58         /*
59          * With debugging enabled, kunmap_atomic forces that entry to 0.
60          * Make sure it was indeed properly unmapped.
61          */
62         BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
63 #endif
64         set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
65         /*
66          * When debugging is off, kunmap_atomic leaves the previous mapping
67          * in place, so this TLB flush ensures the TLB is updated with the
68          * new mapping.
69          */
70         local_flush_tlb_kernel_page(vaddr);
71
72         return (void *)vaddr;
73 }
74 EXPORT_SYMBOL(kmap_atomic);
75
76 void kunmap_atomic(void *kvaddr, enum km_type type)
77 {
78         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
79         unsigned int idx = type + KM_TYPE_NR * smp_processor_id();
80
81         if (kvaddr >= (void *)FIXADDR_START) {
82                 __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
83 #ifdef CONFIG_DEBUG_HIGHMEM
84                 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
85                 set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
86                 local_flush_tlb_kernel_page(vaddr);
87 #else
88                 (void) idx;  /* to kill a warning */
89 #endif
90         } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
91                 /* this address was obtained through kmap_high_get() */
92                 kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
93         }
94         pagefault_enable();
95 }
96 EXPORT_SYMBOL(kunmap_atomic);
97
98 void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
99 {
100         unsigned int idx;
101         unsigned long vaddr;
102
103         pagefault_disable();
104
105         idx = type + KM_TYPE_NR * smp_processor_id();
106         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
107 #ifdef CONFIG_DEBUG_HIGHMEM
108         BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
109 #endif
110         set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
111         local_flush_tlb_kernel_page(vaddr);
112
113         return (void *)vaddr;
114 }
115
116 struct page *kmap_atomic_to_page(const void *ptr)
117 {
118         unsigned long vaddr = (unsigned long)ptr;
119         pte_t *pte;
120
121         if (vaddr < FIXADDR_START)
122                 return virt_to_page(ptr);
123
124         pte = TOP_PTE(vaddr);
125         return pte_page(*pte);
126 }