source: trunk/packages/xen-3.1/xen-3.1/linux-2.6-xen-sparse/include/asm-x86_64/mach-xen/asm/fixmap.h @ 34

/*
 * 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
 */

#ifndef _ASM_FIXMAP_H
#define _ASM_FIXMAP_H

#include <linux/kernel.h>
#include <asm/apicdef.h>
#include <asm/page.h>
#include <asm/vsyscall.h>
#include <asm/vsyscall32.h>
#include <asm/acpi.h>

/*
 * 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.
 *
 * 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 {
        VSYSCALL_LAST_PAGE,
        VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
        VSYSCALL_HPET,
        FIX_HPET_BASE,
#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_ACPI
        FIX_ACPI_BEGIN,
        FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
#endif
        FIX_SHARED_INFO,
#define NR_FIX_ISAMAPS  256
        FIX_ISAMAP_END,
        FIX_ISAMAP_BEGIN = FIX_ISAMAP_END + NR_FIX_ISAMAPS - 1,
        __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,
        __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))

#define FIXADDR_TOP     (VSYSCALL_END-PAGE_SIZE)
#define FIXADDR_SIZE    (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START   (FIXADDR_TOP - FIXADDR_SIZE)

/* Only covers 32bit vsyscalls currently. Need another set for 64bit. */
#define FIXADDR_USER_START      ((unsigned long)VSYSCALL32_VSYSCALL)
#define FIXADDR_USER_END        (FIXADDR_USER_START + PAGE_SIZE)

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

extern void __this_fixmap_does_not_exist(void);

/*
 * 'index to address' translation. If anyone tries to use the idx
 * directly without translation, we catch the bug with a NULL-deference
 * kernel oops. Illegal ranges of incoming indices are caught too.
 */
static __always_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);
}

#endif