80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/*
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* fixmap.h: compile-time virtual memory allocation
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1998 Ingo Molnar
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*
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* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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*/
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#ifndef _ASM_FIXMAP_H
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#define _ASM_FIXMAP_H
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#include <asm/page.h>
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#include <spaces.h>
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#ifdef CONFIG_HIGHMEM
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#include <linux/threads.h>
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#include <asm/kmap_size.h>
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#endif
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/*
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* Here we define all the compile-time 'special' virtual
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* addresses. The point is to have a constant address at
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* compile time, but to set the physical address only
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* in the boot process. We allocate these special addresses
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* from the end of virtual memory (0xfffff000) backwards.
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* Also this lets us do fail-safe vmalloc(), we
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* can guarantee that these special addresses and
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* vmalloc()-ed addresses never overlap.
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*
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* these 'compile-time allocated' memory buffers are
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* fixed-size 4k pages. (or larger if used with an increment
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* highger than 1) use fixmap_set(idx,phys) to associate
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* physical memory with fixmap indices.
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*
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* TLB entries of such buffers will not be flushed across
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* task switches.
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*/
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/*
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* on UP currently we will have no trace of the fixmap mechanizm,
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* no page table allocations, etc. This might change in the
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* future, say framebuffers for the console driver(s) could be
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* fix-mapped?
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*/
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enum fixed_addresses {
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#define FIX_N_COLOURS 8
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FIX_CMAP_BEGIN,
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FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2),
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#ifdef CONFIG_HIGHMEM
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/* reserved pte's for temporary kernel mappings */
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FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
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FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
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#endif
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__end_of_fixed_addresses
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};
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/*
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* used by vmalloc.c.
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*
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* Leave one empty page between vmalloc'ed areas and
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* the start of the fixmap, and leave one page empty
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* at the top of mem..
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*/
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#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
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#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
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#include <asm-generic/fixmap.h>
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/*
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* Called from pgtable_init()
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*/
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extern void fixrange_init(unsigned long start, unsigned long end,
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pgd_t *pgd_base);
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#endif
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