linux/arch/arm64/include/asm/fixmap.h
Mark Rutland 961faac114 arm64: mm: add functions to walk tables in fixmap
As a preparatory step to allow us to allocate early page tables from
unmapped memory using memblock_alloc, add new p??_{set,clear}_fixmap*
functions which can be used to walk page tables outside of the linear
mapping by using fixmap slots.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 15:10:46 +00:00

96 lines
2.5 KiB
C

/*
* 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
* Copyright (C) 2013 Mark Salter <msalter@redhat.com>
*
* Adapted from arch/x86 version.
*
*/
#ifndef _ASM_ARM64_FIXMAP_H
#define _ASM_ARM64_FIXMAP_H
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
#include <linux/sizes.h>
#include <asm/boot.h>
#include <asm/page.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
* page-sized. Use set_fixmap(idx,phys) to associate
* physical memory with fixmap indices.
*
*/
enum fixed_addresses {
FIX_HOLE,
/*
* Reserve a virtual window for the FDT that is 2 MB larger than the
* maximum supported size, and put it at the top of the fixmap region.
* The additional space ensures that any FDT that does not exceed
* MAX_FDT_SIZE can be mapped regardless of whether it crosses any
* 2 MB alignment boundaries.
*
* Keep this at the top so it remains 2 MB aligned.
*/
#define FIX_FDT_SIZE (MAX_FDT_SIZE + SZ_2M)
FIX_FDT_END,
FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1,
FIX_EARLYCON_MEM_BASE,
FIX_TEXT_POKE0,
__end_of_permanent_fixed_addresses,
/*
* Temporary boot-time mappings, used by early_ioremap(),
* before ioremap() is functional.
*/
#define NR_FIX_BTMAPS (SZ_256K / PAGE_SIZE)
#define FIX_BTMAPS_SLOTS 7
#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
/*
* Used for kernel page table creation, so unmapped memory may be used
* for tables.
*/
FIX_PTE,
FIX_PMD,
FIX_PUD,
FIX_PGD,
__end_of_fixed_addresses
};
#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
#define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE)
void __init early_fixmap_init(void);
#define __early_set_fixmap __set_fixmap
#define __late_set_fixmap __set_fixmap
#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
#include <asm-generic/fixmap.h>
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_ARM64_FIXMAP_H */