92 lines
2.7 KiB
C
92 lines
2.7 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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#ifndef _ASM_FIXMAP_H
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#define _ASM_FIXMAP_H
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#include <linux/kernel.h>
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#include <asm/apicdef.h>
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#include <asm/page.h>
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#include <asm/vsyscall.h>
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#include <asm/vsyscall32.h>
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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.
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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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enum fixed_addresses {
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VSYSCALL_LAST_PAGE,
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VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
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VSYSCALL_HPET,
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FIX_HPET_BASE,
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FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
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FIX_IO_APIC_BASE_0,
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FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
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__end_of_fixed_addresses
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};
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extern void __set_fixmap (enum fixed_addresses idx,
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unsigned long phys, pgprot_t flags);
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#define set_fixmap(idx, phys) \
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__set_fixmap(idx, phys, PAGE_KERNEL)
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/*
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* Some hardware wants to get fixmapped without caching.
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*/
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#define set_fixmap_nocache(idx, phys) \
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__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
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#define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE)
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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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/* Only covers 32bit vsyscalls currently. Need another set for 64bit. */
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#define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL)
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#define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
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#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
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extern void __this_fixmap_does_not_exist(void);
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/*
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* 'index to address' translation. If anyone tries to use the idx
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* directly without translation, we catch the bug with a NULL-deference
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* kernel oops. Illegal ranges of incoming indices are caught too.
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*/
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static __always_inline unsigned long fix_to_virt(const unsigned int idx)
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{
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/*
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* this branch gets completely eliminated after inlining,
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* except when someone tries to use fixaddr indices in an
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* illegal way. (such as mixing up address types or using
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* out-of-range indices).
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*
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* If it doesn't get removed, the linker will complain
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* loudly with a reasonably clear error message..
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*/
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if (idx >= __end_of_fixed_addresses)
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__this_fixmap_does_not_exist();
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return __fix_to_virt(idx);
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}
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#endif
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