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/*

 * fixmap.h: compile-time virtual memory allocation

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 1998 Ingo Molnar

 *

 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999

 */

#ifndef _ASM_FIXMAP_H

#define _ASM_FIXMAP_H

#include <linux/config.h>

#include <linux/kernel.h>

#include <asm/acpi.h>

#include <asm/apicdef.h>

#include <asm/page.h>

#ifdef CONFIG_HIGHMEM

#include <linux/threads.h>

#include <asm/kmap_types.h>

#endif

/*

 * Here we define all the compile-time 'special' virtual

 * addresses. The point is to have a constant address at

 * compile time, but to set the physical address only

 * in the boot process. We allocate these special addresses

 * from the end of virtual memory (0xfffff000) backwards.

 * Also this lets us do fail-safe vmalloc(), we

 * can guarantee that these special addresses and

 * vmalloc()-ed addresses never overlap.

 *

 * these 'compile-time allocated' memory buffers are

 * fixed-size 4k pages. (or larger if used with an increment

 * highger than 1) use fixmap_set(idx,phys) to associate

 * physical memory with fixmap indices.

 *

 * TLB entries of such buffers will not be flushed across

 * task switches.

 */

enum fixed_addresses {

        FIX_HOLE,

        FIX_VSYSCALL,

#ifdef CONFIG_X86_LOCAL_APIC

        FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */

#endif

#ifdef CONFIG_X86_IO_APIC

        FIX_IO_APIC_BASE_0,

        FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,

#endif

#ifdef CONFIG_X86_VISWS_APIC

        FIX_CO_CPU,     /* Cobalt timer */

        FIX_CO_APIC,    /* Cobalt APIC Redirection Table */

        FIX_LI_PCIA,    /* Lithium PCI Bridge A */

        FIX_LI_PCIB,    /* Lithium PCI Bridge B */

#endif

#ifdef CONFIG_X86_F00F_BUG

        FIX_F00F_IDT,   /* Virtual mapping for IDT */

#endif

#ifdef CONFIG_X86_CYCLONE_TIMER

        FIX_CYCLONE_TIMER, /*cyclone timer register*/

#endif 

#ifdef CONFIG_HIGHMEM

        FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */

        FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,

#endif

#ifdef CONFIG_ACPI_BOOT

        FIX_ACPI_BEGIN,

        FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,

#endif

        __end_of_permanent_fixed_addresses,

        /* temporary boot-time mappings, used before ioremap() is functional */

#define NR_FIX_BTMAPS   16

        FIX_BTMAP_END = __end_of_permanent_fixed_addresses,

        FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,

        FIX_WP_TEST,

        __end_of_fixed_addresses

};

extern void __set_fixmap (enum fixed_addresses idx,

                                        unsigned long phys, pgprot_t flags);

#define set_fixmap(idx, phys) \

                __set_fixmap(idx, phys, PAGE_KERNEL)

/*

 * Some hardware wants to get fixmapped without caching.

 */

#define set_fixmap_nocache(idx, phys) \

                __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)

#define clear_fixmap(idx) \

                __set_fixmap(idx, 0, __pgprot(0))

/*

 * used by vmalloc.c.

 *

 * Leave one empty page between vmalloc'ed areas and

 * the start of the fixmap.

 */

#define FIXADDR_TOP     (0xfffff000UL)

#define __FIXADDR_SIZE  (__end_of_permanent_fixed_addresses << PAGE_SHIFT)

#define FIXADDR_START   (FIXADDR_TOP - __FIXADDR_SIZE)

#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))

#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)

/*

 * This is the range that is readable by user mode, and things

 * acting like user mode such as get_user_pages.

 */

#define FIXADDR_USER_START      (__fix_to_virt(FIX_VSYSCALL))

#define FIXADDR_USER_END        (FIXADDR_USER_START + PAGE_SIZE)

extern void __this_fixmap_does_not_exist(void);

/*

 * 'index to address' translation. If anyone tries to use the idx

 * directly without tranlation, we catch the bug with a NULL-deference

 * kernel oops. Illegal ranges of incoming indices are caught too.

 */

static inline unsigned long fix_to_virt(const unsigned int idx)

{

        /*

         * this branch gets completely eliminated after inlining,

         * except when someone tries to use fixaddr indices in an

         * illegal way. (such as mixing up address types or using

         * out-of-range indices).

         *

         * If it doesn't get removed, the linker will complain

         * loudly with a reasonably clear error message..

         */

        if (idx >= __end_of_fixed_addresses)

                __this_fixmap_does_not_exist();

        return __fix_to_virt(idx);

}

static inline unsigned long virt_to_fix(const unsigned long vaddr)

{

        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);

        return __virt_to_fix(vaddr);

}

#endif