/*

 * 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>

/*

 * 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

	__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 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