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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - include/asm-sparc/fixmap.h
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
16 #include <linux/config.h>
17 #include <linux/kernel.h>
20 #include <linux/threads.h>
21 #include <asm/kmap_types.h>
25 * Here we define all the compile-time 'special' virtual
26 * addresses. The point is to have a constant address at
27 * compile time, but to set the physical address only
28 * in the boot process. We allocate these special addresses
29 * from the top of unused virtual memory (0xfd000000 - 1 page) backwards.
30 * Also this lets us do fail-safe vmalloc(), we
31 * can guarantee that these special addresses and
32 * vmalloc()-ed addresses never overlap.
34 * these 'compile-time allocated' memory buffers are
35 * fixed-size 4k pages. (or larger if used with an increment
36 * highger than 1) use fixmap_set(idx,phys) to associate
37 * physical memory with fixmap indices.
39 * TLB entries of such buffers will not be flushed across
44 * on UP currently we will have no trace of the fixmap mechanism,
45 * no page table allocations, etc. This might change in the
46 * future, say framebuffers for the console driver(s) could be
49 enum fixed_addresses
{
53 FIX_KMAP_END
= FIX_KMAP_BEGIN
+(KM_TYPE_NR
*NR_CPUS
)-1,
55 __end_of_fixed_addresses
58 extern void __set_fixmap (enum fixed_addresses idx
,
59 unsigned long phys
, pgprot_t flags
);
61 #define set_fixmap(idx, phys) \
62 __set_fixmap(idx, phys, PAGE_KERNEL)
64 * Some hardware wants to get fixmapped without caching.
66 #define set_fixmap_nocache(idx, phys) \
67 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
71 * Leave one empty page between IO pages at 0xfd000000 and
72 * the start of the fixmap.
74 #define FIXADDR_TOP (0xfcfff000UL)
75 #define FIXADDR_SIZE ((__end_of_fixed_addresses) << PAGE_SHIFT)
76 #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
78 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
79 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
81 extern void __this_fixmap_does_not_exist(void);
84 * 'index to address' translation. If anyone tries to use the idx
85 * directly without tranlation, we catch the bug with a NULL-deference
86 * kernel oops. Illegal ranges of incoming indices are caught too.
88 static inline unsigned long fix_to_virt(const unsigned int idx
)
91 * this branch gets completely eliminated after inlining,
92 * except when someone tries to use fixaddr indices in an
93 * illegal way. (such as mixing up address types or using
94 * out-of-range indices).
96 * If it doesn't get removed, the linker will complain
97 * loudly with a reasonably clear error message..
99 if (idx
>= __end_of_fixed_addresses
)
100 __this_fixmap_does_not_exist();
102 return __fix_to_virt(idx
);
105 static inline unsigned long virt_to_fix(const unsigned long vaddr
)
107 BUG_ON(vaddr
>= FIXADDR_TOP
|| vaddr
< FIXADDR_START
);
108 return __virt_to_fix(vaddr
);