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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/pgtable.h>
17#ifdef CONFIG_HIGHMEM
18#include <linux/threads.h>
19#include <asm/kmap_types.h>
20#endif
21
22/*
23 * Here we define all the compile-time 'special' virtual
24 * addresses. The point is to have a constant address at
25 * compile time, but to set the physical address only
26 * in the boot process. We allocate these special addresses
27 * from the end of the consistent memory region backwards.
28 * Also this lets us do fail-safe vmalloc(), we
29 * can guarantee that these special addresses and
30 * vmalloc()-ed addresses never overlap.
31 *
32 * these 'compile-time allocated' memory buffers are
33 * fixed-size 4k pages. (or larger if used with an increment
34 * higher than 1) use fixmap_set(idx,phys) to associate
35 * physical memory with fixmap indices.
36 */
37enum fixed_addresses {
38#ifdef CONFIG_HIGHMEM
39 /* reserved pte's for temporary kernel mappings */
40 FIX_KMAP_BEGIN,
41 FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
42#endif
43 __end_of_fixed_addresses
44};
45
46#define FIXADDR_TOP (VMALLOC_START - PAGE_SIZE)
47#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
48#define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK)
49
50#include <asm-generic/fixmap.h>
51
52#define kmap_get_fixmap_pte(vaddr) \
53 pte_offset_kernel( \
54 pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), \
55 (vaddr) \
56 )
57
58#endif