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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/pgtable.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 start of the consistent memory region upwards.
* 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
* higher than 1) use fixmap_set(idx,phys) to associate
* physical memory with fixmap indices.
*/
enum fixed_addresses {
#ifdef CONFIG_HIGHMEM
/* reserved pte's for temporary kernel mappings */
FIX_KMAP_BEGIN,
FIX_KMAP_END = FIX_KMAP_BEGIN +
(KM_TYPE_NR * NR_CPUS * DCACHE_N_COLORS) - 1,
#endif
__end_of_fixed_addresses
};
#define FIXADDR_TOP (XCHAL_KSEG_CACHED_VADDR - PAGE_SIZE)
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START ((FIXADDR_TOP - FIXADDR_SIZE) & PMD_MASK)
#define __fix_to_virt(x) (FIXADDR_START + ((x) << PAGE_SHIFT))
#define __virt_to_fix(x) (((x) - FIXADDR_START) >> PAGE_SHIFT)
#ifndef __ASSEMBLY__
/*
* '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)
{
/* Check if this memory layout is broken because fixmap overlaps page
* table.
*/
BUILD_BUG_ON(FIXADDR_START <
TLBTEMP_BASE_1 + TLBTEMP_SIZE);
BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
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
#define kmap_get_fixmap_pte(vaddr) \
pte_offset_kernel( \
pmd_offset(pud_offset(p4d_offset(pgd_offset_k(vaddr), \
(vaddr)), \
(vaddr)), \
(vaddr)), \
(vaddr))
#endif
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