1 /* 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 */
26 extern unsigned long highstart_pfn, highend_pfn;
27
28 extern pte_t *kmap_pte;
29 extern pgprot_t kmap_prot;
30 extern pte_t *pkmap_page_table;
31
32 extern 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
45 extern unsigned long kmap_high(struct page *page);
46 extern void kunmap_high(struct page *page);
47
kmap(struct page * page)48 static 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
kunmap(struct page * page)57 static 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 */
kmap_atomic(struct page * page,enum km_type type)72 static 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
kunmap_atomic(unsigned long vaddr,enum km_type type)92 static 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 */
115