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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
11#ifndef _ASM_FIXMAP_H
12#define _ASM_FIXMAP_H
13
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/kernel.h>
15#include <asm/apicdef.h>
16#include <asm/page.h>
17#include <asm/vsyscall.h>
Huang, Ying5b836832008-01-30 13:31:19 +010018#include <asm/efi.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
20/*
21 * Here we define all the compile-time 'special' virtual
22 * addresses. The point is to have a constant address at
23 * compile time, but to set the physical address only
24 * in the boot process.
25 *
Jiri Kosinabdb345a2007-07-21 17:11:21 +020026 * These 'compile-time allocated' memory buffers are
27 * fixed-size 4k pages (or larger if used with an increment
28 * higher than 1). Use set_fixmap(idx,phys) to associate
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 * physical memory with fixmap indices.
30 *
31 * TLB entries of such buffers will not be flushed across
32 * task switches.
33 */
34
35enum fixed_addresses {
36 VSYSCALL_LAST_PAGE,
Joe Perchesdca13fb2008-03-23 01:02:10 -070037 VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE
38 + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 VSYSCALL_HPET,
Yinghai Lu18a8bd92007-07-15 23:37:59 -070040 FIX_DBGP_BASE,
41 FIX_EARLYCON_MEM_BASE,
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 FIX_HPET_BASE,
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 FIX_IO_APIC_BASE_0,
Joe Perchesdca13fb2008-03-23 01:02:10 -070045 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
Huang, Ying5b836832008-01-30 13:31:19 +010046 FIX_EFI_IO_MAP_LAST_PAGE,
Joe Perchesdca13fb2008-03-23 01:02:10 -070047 FIX_EFI_IO_MAP_FIRST_PAGE = FIX_EFI_IO_MAP_LAST_PAGE
48 + MAX_EFI_IO_PAGES - 1,
Bernhard Kaindlf212ec42008-01-30 13:34:11 +010049#ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
50 FIX_OHCI1394_BASE,
51#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 __end_of_fixed_addresses
53};
54
Joe Perchesdca13fb2008-03-23 01:02:10 -070055extern void __set_fixmap(enum fixed_addresses idx,
56 unsigned long phys, pgprot_t flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Joe Perchesdca13fb2008-03-23 01:02:10 -070058#define set_fixmap(idx, phys) \
59 __set_fixmap(idx, phys, PAGE_KERNEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -070060/*
61 * Some hardware wants to get fixmapped without caching.
62 */
Joe Perchesdca13fb2008-03-23 01:02:10 -070063#define set_fixmap_nocache(idx, phys) \
64 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66#define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE)
67#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
68#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
69
70/* Only covers 32bit vsyscalls currently. Need another set for 64bit. */
71#define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL)
72#define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
73
74#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
75
76extern void __this_fixmap_does_not_exist(void);
77
78/*
79 * 'index to address' translation. If anyone tries to use the idx
80 * directly without translation, we catch the bug with a NULL-deference
81 * kernel oops. Illegal ranges of incoming indices are caught too.
82 */
Ingo Molnar652050a2006-01-14 13:21:30 -080083static __always_inline unsigned long fix_to_virt(const unsigned int idx)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084{
85 /*
86 * this branch gets completely eliminated after inlining,
87 * except when someone tries to use fixaddr indices in an
88 * illegal way. (such as mixing up address types or using
89 * out-of-range indices).
90 *
91 * If it doesn't get removed, the linker will complain
92 * loudly with a reasonably clear error message..
93 */
94 if (idx >= __end_of_fixed_addresses)
95 __this_fixmap_does_not_exist();
96
Yinghai Lu18a8bd92007-07-15 23:37:59 -070097 return __fix_to_virt(idx);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098}
99
100#endif