2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 21:54:06 +08:00
linux-next/arch/arm64/kernel/image-vars.h
Ard Biesheuvel b9676962cd efi/arm64: Clean EFI stub exit code from cache instead of avoiding it
Commit 9f9223778 ("efi/libstub/arm: Make efi_entry() an ordinary PE/COFF
entrypoint") modified the handover code written in assembler, and for
maintainability, aligned the logic with the logic used in the 32-bit ARM
version, which is to avoid cache maintenance on the remaining instructions
in the subroutine that will be executed with the MMU and caches off, and
instead, branch into the relocated copy of the kernel image.

However, this assumes that this copy is executable, and this means we
expect EFI_LOADER_DATA regions to be executable as well, which is not
a reasonable assumption to make, even if this is true for most UEFI
implementations today.

So change this back, and add a __clean_dcache_area_poc() call to cover
the remaining code in the subroutine. While at it, switch the other
call site over to __clean_dcache_area_poc() as well, and clean up the
terminology in comments to avoid using 'flush' in the context of cache
maintenance. Also, let's switch to the new style asm annotations.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-efi@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20200228121408.9075-6-ardb@kernel.org
2020-02-29 10:16:57 +01:00

55 lines
1.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Linker script variables to be set after section resolution, as
* ld.lld does not like variables assigned before SECTIONS is processed.
*/
#ifndef __ARM64_KERNEL_IMAGE_VARS_H
#define __ARM64_KERNEL_IMAGE_VARS_H
#ifndef LINKER_SCRIPT
#error This file should only be included in vmlinux.lds.S
#endif
#ifdef CONFIG_EFI
__efistub_kernel_size = _edata - _text;
__efistub_stext_offset = stext - _text;
/*
* The EFI stub has its own symbol namespace prefixed by __efistub_, to
* isolate it from the kernel proper. The following symbols are legally
* accessed by the stub, so provide some aliases to make them accessible.
* Only include data symbols here, or text symbols of functions that are
* guaranteed to be safe when executed at another offset than they were
* linked at. The routines below are all implemented in assembler in a
* position independent manner
*/
__efistub_memcmp = __pi_memcmp;
__efistub_memchr = __pi_memchr;
__efistub_memcpy = __pi_memcpy;
__efistub_memmove = __pi_memmove;
__efistub_memset = __pi_memset;
__efistub_strlen = __pi_strlen;
__efistub_strnlen = __pi_strnlen;
__efistub_strcmp = __pi_strcmp;
__efistub_strncmp = __pi_strncmp;
__efistub_strrchr = __pi_strrchr;
__efistub___clean_dcache_area_poc = __pi___clean_dcache_area_poc;
#ifdef CONFIG_KASAN
__efistub___memcpy = __pi_memcpy;
__efistub___memmove = __pi_memmove;
__efistub___memset = __pi_memset;
#endif
__efistub__text = _text;
__efistub__end = _end;
__efistub__edata = _edata;
__efistub_screen_info = screen_info;
__efistub__ctype = _ctype;
#endif
#endif /* __ARM64_KERNEL_IMAGE_VARS_H */