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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 * Copyright 2008 Freescale Semiconductor Inc.
11 * Port to powerpc added by Kumar Gala
12 */
13
14#ifndef _ASM_FIXMAP_H
15#define _ASM_FIXMAP_H
16
17#ifndef __ASSEMBLY__
18#include <linux/kernel.h>
19#include <asm/page.h>
20#ifdef CONFIG_HIGHMEM
21#include <linux/threads.h>
22#include <asm/kmap_types.h>
23#endif
24
25#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
26
27/*
28 * Here we define all the compile-time 'special' virtual
29 * addresses. The point is to have a constant address at
30 * compile time, but to set the physical address only
31 * in the boot process. We allocate these special addresses
32 * from the end of virtual memory (0xfffff000) backwards.
33 * Also this lets us do fail-safe vmalloc(), we
34 * can guarantee that these special addresses and
35 * vmalloc()-ed addresses never overlap.
36 *
37 * these 'compile-time allocated' memory buffers are
38 * fixed-size 4k pages. (or larger if used with an increment
39 * highger than 1) use fixmap_set(idx,phys) to associate
40 * physical memory with fixmap indices.
41 *
42 * TLB entries of such buffers will not be flushed across
43 * task switches.
44 */
45enum fixed_addresses {
46 FIX_HOLE,
47 /* reserve the top 128K for early debugging purposes */
48 FIX_EARLY_DEBUG_TOP = FIX_HOLE,
49 FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+((128*1024)/PAGE_SIZE)-1,
50#ifdef CONFIG_HIGHMEM
51 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
52 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
53#endif
54 /* FIX_PCIE_MCFG, */
55 __end_of_fixed_addresses
56};
57
58extern void __set_fixmap (enum fixed_addresses idx,
59 phys_addr_t phys, pgprot_t flags);
60
61#define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
62#define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
63
64#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NCG
65
66#include <asm-generic/fixmap.h>
67
68#endif /* !__ASSEMBLY__ */
69#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 * Copyright 2008 Freescale Semiconductor Inc.
11 * Port to powerpc added by Kumar Gala
12 */
13
14#ifndef _ASM_FIXMAP_H
15#define _ASM_FIXMAP_H
16
17#ifndef __ASSEMBLY__
18#include <linux/kernel.h>
19#include <asm/page.h>
20#ifdef CONFIG_HIGHMEM
21#include <linux/threads.h>
22#include <asm/kmap_types.h>
23#endif
24
25#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
26
27/*
28 * Here we define all the compile-time 'special' virtual
29 * addresses. The point is to have a constant address at
30 * compile time, but to set the physical address only
31 * in the boot process. We allocate these special addresses
32 * from the end of virtual memory (0xfffff000) backwards.
33 * Also this lets us do fail-safe vmalloc(), we
34 * can guarantee that these special addresses and
35 * vmalloc()-ed addresses never overlap.
36 *
37 * these 'compile-time allocated' memory buffers are
38 * fixed-size 4k pages. (or larger if used with an increment
39 * highger than 1) use fixmap_set(idx,phys) to associate
40 * physical memory with fixmap indices.
41 *
42 * TLB entries of such buffers will not be flushed across
43 * task switches.
44 */
45enum fixed_addresses {
46 FIX_HOLE,
47 /* reserve the top 128K for early debugging purposes */
48 FIX_EARLY_DEBUG_TOP = FIX_HOLE,
49 FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+((128*1024)/PAGE_SIZE)-1,
50#ifdef CONFIG_HIGHMEM
51 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
52 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
53#endif
54 /* FIX_PCIE_MCFG, */
55 __end_of_fixed_addresses
56};
57
58extern void __set_fixmap (enum fixed_addresses idx,
59 phys_addr_t phys, pgprot_t flags);
60
61#define set_fixmap(idx, phys) \
62 __set_fixmap(idx, phys, PAGE_KERNEL)
63/*
64 * Some hardware wants to get fixmapped without caching.
65 */
66#define set_fixmap_nocache(idx, phys) \
67 __set_fixmap(idx, phys, PAGE_KERNEL_NCG)
68
69#define clear_fixmap(idx) \
70 __set_fixmap(idx, 0, __pgprot(0))
71
72#define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
73#define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
74
75#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
76#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
77
78extern void __this_fixmap_does_not_exist(void);
79
80/*
81 * 'index to address' translation. If anyone tries to use the idx
82 * directly without tranlation, we catch the bug with a NULL-deference
83 * kernel oops. Illegal ranges of incoming indices are caught too.
84 */
85static __always_inline unsigned long fix_to_virt(const unsigned int idx)
86{
87 /*
88 * this branch gets completely eliminated after inlining,
89 * except when someone tries to use fixaddr indices in an
90 * illegal way. (such as mixing up address types or using
91 * out-of-range indices).
92 *
93 * If it doesn't get removed, the linker will complain
94 * loudly with a reasonably clear error message..
95 */
96 if (idx >= __end_of_fixed_addresses)
97 __this_fixmap_does_not_exist();
98
99 return __fix_to_virt(idx);
100}
101
102static inline unsigned long virt_to_fix(const unsigned long vaddr)
103{
104 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
105 return __virt_to_fix(vaddr);
106}
107
108#endif /* !__ASSEMBLY__ */
109#endif