linux/arch/arm/include/asm/efi.h
Ard Biesheuvel 138728dd4e efi/arm-stub: Correct FDT and initrd allocation rules for arm64
On arm64, we have made some changes over the past year to the way the
kernel itself is allocated and to how it deals with the initrd and FDT.
This patch brings the allocation logic in the EFI stub in line with that,
which is necessary because the introduction of KASLR has created the
possibility for the initrd to be allocated in a place where the kernel
may not be able to map it. (This is mostly a theoretical scenario, since
it only affects systems where the physical memory footprint exceeds the
size of the linear mapping.)

Since we know the kernel itself will be covered by the linear mapping,
choose a suitably sized window (i.e., based on the size of the linear
region) covering the kernel when allocating memory for the initrd.

The FDT may be anywhere in memory on arm64 now that we map it via the
fixmap, so we can lift the address restriction there completely.

Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-4-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-05 12:27:23 +02:00

103 lines
3.0 KiB
C

/*
* Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __ASM_ARM_EFI_H
#define __ASM_ARM_EFI_H
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/early_ioremap.h>
#include <asm/fixmap.h>
#include <asm/highmem.h>
#include <asm/mach/map.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/ptrace.h>
#ifdef CONFIG_EFI
void efi_init(void);
int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
#define arch_efi_call_virt_setup() efi_virtmap_load()
#define arch_efi_call_virt_teardown() efi_virtmap_unload()
#define arch_efi_call_virt(p, f, args...) \
({ \
efi_##f##_t *__f; \
__f = p->f; \
__f(args); \
})
#define ARCH_EFI_IRQ_FLAGS_MASK \
(PSR_J_BIT | PSR_E_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | \
PSR_T_BIT | MODE_MASK)
static inline void efi_set_pgd(struct mm_struct *mm)
{
check_and_switch_context(mm, NULL);
}
void efi_virtmap_load(void);
void efi_virtmap_unload(void);
#else
#define efi_init()
#endif /* CONFIG_EFI */
/* arch specific definitions used by the stub code */
#define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__)
#define __efi_call_early(f, ...) f(__VA_ARGS__)
#define efi_call_runtime(f, ...) sys_table_arg->runtime->f(__VA_ARGS__)
#define efi_is_64bit() (false)
#define efi_call_proto(protocol, f, instance, ...) \
((protocol##_t *)instance)->f(instance, ##__VA_ARGS__)
struct screen_info *alloc_screen_info(efi_system_table_t *sys_table_arg);
void free_screen_info(efi_system_table_t *sys_table, struct screen_info *si);
static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
{
}
/*
* A reasonable upper bound for the uncompressed kernel size is 32 MBytes,
* so we will reserve that amount of memory. We have no easy way to tell what
* the actuall size of code + data the uncompressed kernel will use.
* If this is insufficient, the decompressor will relocate itself out of the
* way before performing the decompression.
*/
#define MAX_UNCOMP_KERNEL_SIZE SZ_32M
/*
* The kernel zImage should preferably be located between 32 MB and 128 MB
* from the base of DRAM. The min address leaves space for a maximal size
* uncompressed image, and the max address is due to how the zImage decompressor
* picks a destination address.
*/
#define ZIMAGE_OFFSET_LIMIT SZ_128M
#define MIN_ZIMAGE_OFFSET MAX_UNCOMP_KERNEL_SIZE
/* on ARM, the FDT should be located in the first 128 MB of RAM */
static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
{
return dram_base + ZIMAGE_OFFSET_LIMIT;
}
/* on ARM, the initrd should be loaded in a lowmem region */
static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
unsigned long image_addr)
{
return dram_base + SZ_512M;
}
#endif /* _ASM_ARM_EFI_H */