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