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422 giacomo 1
/*
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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 <linux/config.h>
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#include <linux/kernel.h>
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#include <asm/acpi.h>
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#include <asm/apicdef.h>
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#include <asm/page.h>
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#ifdef CONFIG_HIGHMEM
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#include <linux/threads.h>
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#include <asm/kmap_types.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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enum fixed_addresses {
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        FIX_HOLE,
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        FIX_VSYSCALL,
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#ifdef CONFIG_X86_LOCAL_APIC
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        FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
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#endif
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#ifdef CONFIG_X86_IO_APIC
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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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#endif
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#ifdef CONFIG_X86_VISWS_APIC
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        FIX_CO_CPU,     /* Cobalt timer */
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        FIX_CO_APIC,    /* Cobalt APIC Redirection Table */
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        FIX_LI_PCIA,    /* Lithium PCI Bridge A */
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        FIX_LI_PCIB,    /* Lithium PCI Bridge B */
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#endif
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#ifdef CONFIG_X86_F00F_BUG
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        FIX_F00F_IDT,   /* Virtual mapping for IDT */
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#endif
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#ifdef CONFIG_X86_CYCLONE_TIMER
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        FIX_CYCLONE_TIMER, /*cyclone timer register*/
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#endif 
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#ifdef CONFIG_HIGHMEM
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        FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
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        FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
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#endif
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#ifdef CONFIG_ACPI_BOOT
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        FIX_ACPI_BEGIN,
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        FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
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#endif
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        __end_of_permanent_fixed_addresses,
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        /* temporary boot-time mappings, used before ioremap() is functional */
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#define NR_FIX_BTMAPS   16
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        FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
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        FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
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        FIX_WP_TEST,
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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 clear_fixmap(idx) \
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                __set_fixmap(idx, 0, __pgprot(0))
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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.
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 */
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#define FIXADDR_TOP     (0xfffff000UL)
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#define __FIXADDR_SIZE  (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
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#define FIXADDR_START   (FIXADDR_TOP - __FIXADDR_SIZE)
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#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
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#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
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/*
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 * This is the range that is readable by user mode, and things
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 * acting like user mode such as get_user_pages.
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 */
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#define FIXADDR_USER_START      (__fix_to_virt(FIX_VSYSCALL))
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#define FIXADDR_USER_END        (FIXADDR_USER_START + PAGE_SIZE)
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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 tranlation, 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 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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static inline unsigned long virt_to_fix(const unsigned long vaddr)
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{
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        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
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        return __virt_to_fix(vaddr);
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}
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#endif