基于linux2.6.38.8内核zImage文件的自解压详解

最新推荐文章于 2022-02-11 18:40:42 发布

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最新推荐文章于 2022-02-11 18:40:42 发布 · 4.3k 阅读

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#linux #image #shell #path #makefile #file

本文详细介绍了Linux2.6.38.8内核编译后生成的zImage文件的解压过程。zImage由压缩后的内核piggy.o和包含初始化及解压功能的head.o misc.o两部分组成。在arch/arm/boot/Makefile中，通过objcopy生成zImage，并在运行时自动解压。

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作者：EasyWave 时间：2012.02.18

类别：linux驱动开发声明：转载，请保留链接

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内核编译完成后会生成zImage内核镜像文件。zImage是如何解压的呢？本文将结合关键代码，讲解zImage的解压过程。还是先来看看zImage的组成吧。在内核编译完成后会在arch/arm/boot/下生成zImage。

在arch/arm/boot/Makefile中，如下代码：

#
# arch/arm/boot/Makefile
#
# This file is included by the global makefile so that you can add your own
# architecture-specific flags and dependencies.
#
# 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) 1995-2002 Russell King
#

MKIMAGE         := $(srctree)/scripts/mkuboot.sh

ifneq ($(MACHINE),)
include $(srctree)/$(MACHINE)/Makefile.boot
endif

# Note: the following conditions must always be true:
#   ZRELADDR == virt_to_phys(PAGE_OFFSET + TEXT_OFFSET)
#   PARAMS_PHYS must be within 4MB of ZRELADDR
#   INITRD_PHYS must be in RAM
ZRELADDR    := $(zreladdr-y)
PARAMS_PHYS := $(params_phys-y)
INITRD_PHYS := $(initrd_phys-y)

export ZRELADDR INITRD_PHYS PARAMS_PHYS

targets := Im