linux/arch/arm64/include/asm/fixmap.h
Will Deacon 6c27c4082f arm64: kaslr: Put kernel vectors address in separate data page
The literal pool entry for identifying the vectors base is the only piece
of information in the trampoline page that identifies the true location
of the kernel.

This patch moves it into a page-aligned region of the .rodata section
and maps this adjacent to the trampoline text via an additional fixmap
entry, which protects against any accidental leakage of the trampoline
contents.

Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-12-11 13:41:20 +00:00

109 lines
2.9 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>
#include <asm/pgtable-prot.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,
#ifdef CONFIG_ACPI_APEI_GHES
/* Used for GHES mapping from assorted contexts */
FIX_APEI_GHES_IRQ,
FIX_APEI_GHES_NMI,
#endif /* CONFIG_ACPI_APEI_GHES */
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
FIX_ENTRY_TRAMP_DATA,
FIX_ENTRY_TRAMP_TEXT,
#define TRAMP_VALIAS (__fix_to_virt(FIX_ENTRY_TRAMP_TEXT))
#endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
__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 */