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David Howellsb920de12008-02-08 04:19:31 -08001/* MN10300 Virtual kernel memory mappings for high memory
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from include/asm-i386/highmem.h
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12#ifndef _ASM_HIGHMEM_H
13#define _ASM_HIGHMEM_H
14
15#ifdef __KERNEL__
16
17#include <linux/init.h>
18#include <linux/interrupt.h>
19#include <asm/kmap_types.h>
20#include <asm/pgtable.h>
21
22/* undef for production */
23#undef HIGHMEM_DEBUG
24
25/* declarations for highmem.c */
26extern unsigned long highstart_pfn, highend_pfn;
27
28extern pte_t *kmap_pte;
29extern pgprot_t kmap_prot;
30extern pte_t *pkmap_page_table;
31
32extern void __init kmap_init(void);
33
34/*
35 * Right now we initialize only a single pte table. It can be extended
36 * easily, subsequent pte tables have to be allocated in one physical
37 * chunk of RAM.
38 */
39#define PKMAP_BASE 0xfe000000UL
40#define LAST_PKMAP 1024
41#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
42#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
43#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
44
Harvey Harrison21534302008-02-13 15:03:17 -080045extern unsigned long kmap_high(struct page *page);
46extern void kunmap_high(struct page *page);
David Howellsb920de12008-02-08 04:19:31 -080047
48static inline unsigned long kmap(struct page *page)
49{
50 if (in_interrupt())
51 BUG();
52 if (page < highmem_start_page)
53 return page_address(page);
54 return kmap_high(page);
55}
56
57static inline void kunmap(struct page *page)
58{
59 if (in_interrupt())
60 BUG();
61 if (page < highmem_start_page)
62 return;
63 kunmap_high(page);
64}
65
66/*
67 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
68 * gives a more generic (and caching) interface. But kmap_atomic can
69 * be used in IRQ contexts, so in some (very limited) cases we need
70 * it.
71 */
72static inline unsigned long kmap_atomic(struct page *page, enum km_type type)
73{
74 enum fixed_addresses idx;
75 unsigned long vaddr;
76
77 if (page < highmem_start_page)
78 return page_address(page);
79
80 idx = type + KM_TYPE_NR * smp_processor_id();
81 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
82#if HIGHMEM_DEBUG
83 if (!pte_none(*(kmap_pte - idx)))
84 BUG();
85#endif
86 set_pte(kmap_pte - idx, mk_pte(page, kmap_prot));
87 __flush_tlb_one(vaddr);
88
89 return vaddr;
90}
91
92static inline void kunmap_atomic(unsigned long vaddr, enum km_type type)
93{
94#if HIGHMEM_DEBUG
95 enum fixed_addresses idx = type + KM_TYPE_NR * smp_processor_id();
96
97 if (vaddr < FIXADDR_START) /* FIXME */
98 return;
99
100 if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
101 BUG();
102
103 /*
104 * force other mappings to Oops if they'll try to access
105 * this pte without first remap it
106 */
107 pte_clear(kmap_pte - idx);
108 __flush_tlb_one(vaddr);
109#endif
110}
111
112#endif /* __KERNEL__ */
113
114#endif /* _ASM_HIGHMEM_H */