2 * fixmap.h: compile-time virtual memory allocation
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
8 * Copyright (C) 1998 Ingo Molnar
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
18 #include <linux/threads.h>
19 #include <asm/kmap_types.h>
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 virtual memory (0xfffff000) 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.
32 * these 'compile-time allocated' memory buffers are
33 * fixed-size 4k pages. (or larger if used with an increment
34 * highger than 1) use fixmap_set(idx,phys) to associate
35 * physical memory with fixmap indices.
37 * TLB entries of such buffers will not be flushed across
42 * on UP currently we will have no trace of the fixmap mechanizm,
43 * no page table allocations, etc. This might change in the
44 * future, say framebuffers for the console driver(s) could be
47 enum fixed_addresses
{
48 #define FIX_N_COLOURS 8
50 #ifdef CONFIG_MIPS_MT_SMTC
51 FIX_CMAP_END
= FIX_CMAP_BEGIN
+ (FIX_N_COLOURS
* NR_CPUS
* 2),
53 FIX_CMAP_END
= FIX_CMAP_BEGIN
+ (FIX_N_COLOURS
* 2),
56 /* reserved pte's for temporary kernel mappings */
57 FIX_KMAP_BEGIN
= FIX_CMAP_END
+ 1,
58 FIX_KMAP_END
= FIX_KMAP_BEGIN
+(KM_TYPE_NR
*NR_CPUS
)-1,
60 __end_of_fixed_addresses
63 extern void __set_fixmap (enum fixed_addresses idx
,
64 unsigned long phys
, pgprot_t flags
);
66 #define set_fixmap(idx, phys) \
67 __set_fixmap(idx, phys, PAGE_KERNEL)
69 * Some hardware wants to get fixmapped without caching.
71 #define set_fixmap_nocache(idx, phys) \
72 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
76 * Leave one empty page between vmalloc'ed areas and
77 * the start of the fixmap, and leave one page empty
80 #if defined(CONFIG_CPU_TX39XX) || defined(CONFIG_CPU_TX49XX)
81 #define FIXADDR_TOP ((unsigned long)(long)(int)(0xff000000 - 0x20000))
82 #elif defined(CONFIG_BCM47XX)
83 #define FIXADDR_TOP ((unsigned long)(long)(int)0xf0000000)
85 #define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000)
87 #define FIXADDR_SIZE (__end_of_fixed_addresses << (VALIAS_PAGE_SHIFT))
88 #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
90 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
91 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
93 static inline unsigned long fix_to_virt_noalias(const unsigned int x
, unsigned long pfn
)
95 unsigned long vaddr
= __fix_to_virt(x
);
96 unsigned long poffset
= (pfn
<< PAGE_SHIFT
) & VALIAS_PAGE_OFFSET_MASK
;
97 unsigned long voffset
= vaddr
& VALIAS_PAGE_OFFSET_MASK
;
99 return ((!voffset
|| (poffset
>= voffset
)) ? (vaddr
| poffset
):(vaddr
| poffset
| VALIAS_PAGE_SIZE
));
102 extern void __this_fixmap_does_not_exist(void);
105 * 'index to address' translation. If anyone tries to use the idx
106 * directly without tranlation, we catch the bug with a NULL-deference
107 * kernel oops. Illegal ranges of incoming indices are caught too.
109 static inline unsigned long fix_to_virt(const unsigned int idx
)
112 * this branch gets completely eliminated after inlining,
113 * except when someone tries to use fixaddr indices in an
114 * illegal way. (such as mixing up address types or using
115 * out-of-range indices).
117 * If it doesn't get removed, the linker will complain
118 * loudly with a reasonably clear error message..
120 if (idx
>= __end_of_fixed_addresses
)
121 __this_fixmap_does_not_exist();
123 return __fix_to_virt(idx
);
126 static inline unsigned long virt_to_fix(const unsigned long vaddr
)
128 BUG_ON(vaddr
>= FIXADDR_TOP
|| vaddr
< FIXADDR_START
);
129 return __virt_to_fix(vaddr
);
133 * Called from pgtable_init()
135 extern void fixrange_init(unsigned long start
, unsigned long end
,