Loading...
1/*
2 * fixmap.h: compile-time virtual memory allocation
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 1998 Ingo Molnar
9 *
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
11 */
12
13#ifndef _ASM_FIXMAP_H
14#define _ASM_FIXMAP_H
15
16#include <asm/page.h>
17#include <spaces.h>
18#ifdef CONFIG_HIGHMEM
19#include <linux/threads.h>
20#include <asm/kmap_types.h>
21#endif
22
23/*
24 * Here we define all the compile-time 'special' virtual
25 * addresses. The point is to have a constant address at
26 * compile time, but to set the physical address only
27 * in the boot process. We allocate these special addresses
28 * from the end of virtual memory (0xfffff000) backwards.
29 * Also this lets us do fail-safe vmalloc(), we
30 * can guarantee that these special addresses and
31 * vmalloc()-ed addresses never overlap.
32 *
33 * these 'compile-time allocated' memory buffers are
34 * fixed-size 4k pages. (or larger if used with an increment
35 * highger than 1) use fixmap_set(idx,phys) to associate
36 * physical memory with fixmap indices.
37 *
38 * TLB entries of such buffers will not be flushed across
39 * task switches.
40 */
41
42/*
43 * on UP currently we will have no trace of the fixmap mechanizm,
44 * no page table allocations, etc. This might change in the
45 * future, say framebuffers for the console driver(s) could be
46 * fix-mapped?
47 */
48enum fixed_addresses {
49#define FIX_N_COLOURS 8
50 FIX_CMAP_BEGIN,
51 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2),
52#ifdef CONFIG_HIGHMEM
53 /* reserved pte's for temporary kernel mappings */
54 FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
55 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
56#endif
57 __end_of_fixed_addresses
58};
59
60/*
61 * used by vmalloc.c.
62 *
63 * Leave one empty page between vmalloc'ed areas and
64 * the start of the fixmap, and leave one page empty
65 * at the top of mem..
66 */
67#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
68#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
69
70#include <asm-generic/fixmap.h>
71
72#define kmap_get_fixmap_pte(vaddr) \
73 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
74
75/*
76 * Called from pgtable_init()
77 */
78extern void fixrange_init(unsigned long start, unsigned long end,
79 pgd_t *pgd_base);
80
81
82#endif
1/*
2 * fixmap.h: compile-time virtual memory allocation
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 1998 Ingo Molnar
9 *
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
11 */
12
13#ifndef _ASM_FIXMAP_H
14#define _ASM_FIXMAP_H
15
16#include <asm/page.h>
17#include <spaces.h>
18#ifdef CONFIG_HIGHMEM
19#include <linux/threads.h>
20#include <asm/kmap_types.h>
21#endif
22
23/*
24 * Here we define all the compile-time 'special' virtual
25 * addresses. The point is to have a constant address at
26 * compile time, but to set the physical address only
27 * in the boot process. We allocate these special addresses
28 * from the end of virtual memory (0xfffff000) backwards.
29 * Also this lets us do fail-safe vmalloc(), we
30 * can guarantee that these special addresses and
31 * vmalloc()-ed addresses never overlap.
32 *
33 * these 'compile-time allocated' memory buffers are
34 * fixed-size 4k pages. (or larger if used with an increment
35 * highger than 1) use fixmap_set(idx,phys) to associate
36 * physical memory with fixmap indices.
37 *
38 * TLB entries of such buffers will not be flushed across
39 * task switches.
40 */
41
42/*
43 * on UP currently we will have no trace of the fixmap mechanizm,
44 * no page table allocations, etc. This might change in the
45 * future, say framebuffers for the console driver(s) could be
46 * fix-mapped?
47 */
48enum fixed_addresses {
49#define FIX_N_COLOURS 8
50 FIX_CMAP_BEGIN,
51#ifdef CONFIG_MIPS_MT_SMTC
52 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS * 2),
53#else
54 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2),
55#endif
56#ifdef CONFIG_HIGHMEM
57 /* reserved pte's for temporary kernel mappings */
58 FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
59 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
60#endif
61 __end_of_fixed_addresses
62};
63
64/*
65 * used by vmalloc.c.
66 *
67 * Leave one empty page between vmalloc'ed areas and
68 * the start of the fixmap, and leave one page empty
69 * at the top of mem..
70 */
71#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
72#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
73
74#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
75#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
76
77extern void __this_fixmap_does_not_exist(void);
78
79/*
80 * 'index to address' translation. If anyone tries to use the idx
81 * directly without tranlation, we catch the bug with a NULL-deference
82 * kernel oops. Illegal ranges of incoming indices are caught too.
83 */
84static inline unsigned long fix_to_virt(const unsigned int idx)
85{
86 /*
87 * this branch gets completely eliminated after inlining,
88 * except when someone tries to use fixaddr indices in an
89 * illegal way. (such as mixing up address types or using
90 * out-of-range indices).
91 *
92 * If it doesn't get removed, the linker will complain
93 * loudly with a reasonably clear error message..
94 */
95 if (idx >= __end_of_fixed_addresses)
96 __this_fixmap_does_not_exist();
97
98 return __fix_to_virt(idx);
99}
100
101static inline unsigned long virt_to_fix(const unsigned long vaddr)
102{
103 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
104 return __virt_to_fix(vaddr);
105}
106
107#define kmap_get_fixmap_pte(vaddr) \
108 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
109
110/*
111 * Called from pgtable_init()
112 */
113extern void fixrange_init(unsigned long start, unsigned long end,
114 pgd_t *pgd_base);
115
116
117#endif