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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
*/
#ifndef _ASM_FIXMAP_H
#define _ASM_FIXMAP_H
#include <linux/kernel.h>
#include <asm/apicdef.h>
#include <asm/page.h>
#include <asm/vsyscall.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_DBGP_BASE,
FIX_EARLYCON_MEM_BASE,
FIX_HPET_BASE,
FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
FIX_IO_APIC_BASE_0,
FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-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 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
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