diff options
author | Stephen Warren <swarren@nvidia.com> | 2018-01-03 14:31:51 -0700 |
---|---|---|
committer | Tom Warren <twarren@nvidia.com> | 2018-01-12 09:52:11 -0700 |
commit | 8163faf952c467b01758b8a9a0dc8538e487aa9a (patch) | |
tree | 2964e95d8dccd8367b2115876e7e481a32c2f0ff /arch/arm/cpu/armv8 | |
parent | f097532d279dd7a6ab2d579425d1318051ac1f8d (diff) |
ARMv8: add optional Linux kernel image header
Allow placing a Linux kernel image header at the start of the U-Boot
binary. This is useful since the image header reports the amount of memory
(BSS and similar) that U-Boot needs to use, but that isn't part of the
binary size. This can be used by the code that loads U-Boot into memory to
determine where to load U-Boot, based on other users of memory.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Diffstat (limited to 'arch/arm/cpu/armv8')
-rw-r--r-- | arch/arm/cpu/armv8/linux-kernel-image-header-vars.h | 86 | ||||
-rw-r--r-- | arch/arm/cpu/armv8/start.S | 4 | ||||
-rw-r--r-- | arch/arm/cpu/armv8/u-boot.lds | 4 |
3 files changed, 93 insertions, 1 deletions
diff --git a/arch/arm/cpu/armv8/linux-kernel-image-header-vars.h b/arch/arm/cpu/armv8/linux-kernel-image-header-vars.h new file mode 100644 index 0000000000..3e720937f0 --- /dev/null +++ b/arch/arm/cpu/armv8/linux-kernel-image-header-vars.h @@ -0,0 +1,86 @@ +/* + * (C) Copyright 2017 NVIDIA Corporation <www.nvidia.com> + * + * Derived from Linux kernel v4.14 files: + * + * arch/arm64/include/asm/assembler.h: + * Based on arch/arm/include/asm/assembler.h, arch/arm/mm/proc-macros.S + * Copyright (C) 1996-2000 Russell King + * Copyright (C) 2012 ARM Ltd. + * + * arch/arm64/kernel/head.S: + * Based on arch/arm/kernel/head.S + * Copyright (C) 1994-2002 Russell King + * Copyright (C) 2003-2012 ARM Ltd. + * Authors: Catalin Marinas <catalin.marinas@arm.com> + * Will Deacon <will.deacon@arm.com> + * + * arch/arm64/kernel/image.h: + * Copyright (C) 2014 ARM Ltd. + * + * SPDX-License-Identifier: GPL-2.0 + */ + +/* + * There aren't any ELF relocations we can use to endian-swap values known only + * at link time (e.g. the subtraction of two symbol addresses), so we must get + * the linker to endian-swap certain values before emitting them. + * + * Note that, in order for this to work when building the ELF64 PIE executable + * (for KASLR), these values should not be referenced via R_AARCH64_ABS64 + * relocations, since these are fixed up at runtime rather than at build time + * when PIE is in effect. So we need to split them up in 32-bit high and low + * words. + */ +#ifdef CONFIG_CPU_BIG_ENDIAN +#define DATA_LE32(data) \ + ((((data) & 0x000000ff) << 24) | \ + (((data) & 0x0000ff00) << 8) | \ + (((data) & 0x00ff0000) >> 8) | \ + (((data) & 0xff000000) >> 24)) +#else +#define DATA_LE32(data) ((data) & 0xffffffff) +#endif + +#define DEFINE_IMAGE_LE64(sym, data) \ + sym##_lo32 = DATA_LE32((data) & 0xffffffff); \ + sym##_hi32 = DATA_LE32((data) >> 32) + +#define __MAX(a, b) (((a) > (b)) ? (a) : (b)) +#define __CODE_DATA_SIZE (__bss_start - _start) +#define __BSS_SIZE (__bss_end - __bss_start) +#ifdef CONFIG_SYS_INIT_SP_BSS_OFFSET +#define __MAX_EXTRA_RAM_USAGE __MAX(__BSS_SIZE, CONFIG_SYS_INIT_SP_BSS_OFFSET) +#else +#define __MAX_EXTRA_RAM_USAGE __BSS_SIZE +#endif +#define __MEM_USAGE (__CODE_DATA_SIZE + __MAX_EXTRA_RAM_USAGE) + +#ifdef CONFIG_CPU_BIG_ENDIAN +#define __HEAD_FLAG_BE 1 +#else +#define __HEAD_FLAG_BE 0 +#endif + +#define __HEAD_FLAG_PAGE_SIZE 1 /* 4K hard-coded */ + +#define __HEAD_FLAG_PHYS_BASE 1 + +#define __HEAD_FLAGS ((__HEAD_FLAG_BE << 0) | \ + (__HEAD_FLAG_PAGE_SIZE << 1) | \ + (__HEAD_FLAG_PHYS_BASE << 3)) + +#define TEXT_OFFSET (CONFIG_SYS_TEXT_BASE - \ + CONFIG_LNX_KRNL_IMG_TEXT_OFFSET_BASE) + +/* + * These will output as part of the Image header, which should be little-endian + * regardless of the endianness of the kernel. While constant values could be + * endian swapped in head.S, all are done here for consistency. + */ +#define HEAD_SYMBOLS \ + DEFINE_IMAGE_LE64(_kernel_size_le, __MEM_USAGE); \ + DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET); \ + DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS); + + HEAD_SYMBOLS diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index f385ed40e1..7a98a1c95d 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -19,7 +19,9 @@ .globl _start _start: -#ifdef CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK +#if defined(LINUX_KERNEL_IMAGE_HEADER) +#include <asm/boot0-linux-kernel-header.h> +#elif defined(CONFIG_ENABLE_ARM_SOC_BOOT0_HOOK) /* * Various SoCs need something special and SoC-specific up front in * order to boot, allow them to set that in their boot0.h file and then diff --git a/arch/arm/cpu/armv8/u-boot.lds b/arch/arm/cpu/armv8/u-boot.lds index 22195b8834..7b76e0f9f0 100644 --- a/arch/arm/cpu/armv8/u-boot.lds +++ b/arch/arm/cpu/armv8/u-boot.lds @@ -159,4 +159,8 @@ SECTIONS /DISCARD/ : { *(.plt*) } /DISCARD/ : { *(.interp*) } /DISCARD/ : { *(.gnu*) } + +#ifdef CONFIG_LINUX_KERNEL_IMAGE_HEADER +#include "linux-kernel-image-header-vars.h" +#endif } |