linux uImage/zImage生成过程

最新推荐文章于 2023-03-08 21:19:55 发布

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本文介绍如何使用mkimage工具从zImage或未压缩的Image生成uImage格式，详细解释了Makefile配置过程及scripts/mkuboot.sh脚本的作用。

uImage是zImage通过mkimage工具（在u-boot代码的tools目录中）在前面加了一个64Byte的头生成的。

/usr/bin/mkimage也可以用来生成uImage.

也可以直接在Image（未压缩）的基础上加64Byte的头生成uImage, 如下修改。

linux-3.18.19/arch/arm/boot/Makefile:

-$(obj)/uImage: $(obj)/zImage FORCE

+$(obj)/uImage: $(obj)/Image FORCE

生成uImage 的Makefile部分

nux-3.18.19/arch/arm/boot/Makefile:

$(obj)/uImage: $(obj)/Image FORCE
    @$(check_for_multiple_loadaddr)
    $(call if_changed,uimage)
    @$(kecho) ' Image $@ is ready'
    @cp $@ $(KBUILD_OUTPUT)/

$(call if_changed,uimage)命令，参考 scripts/Makefile.lib中的cmd_uimage

341 # U-Boot mkimage
342 # ---------------------------------------------------------------------------
343
344 MKIMAGE := $(srctree)/scripts/mkuboot.sh
345
346 # SRCARCH just happens to match slightly more than ARCH (on sparc), so reduces
347 # the number of overrides in arch makefiles
348 UIMAGE_ARCH ?= $(SRCARCH)
349 UIMAGE_COMPRESSION ?= $(if $(2),$(2),none)
350 UIMAGE_OPTS-y ?=
351 UIMAGE_TYPE ?= kernel
352 UIMAGE_LOADADDR ?= arch_must_set_this
353 UIMAGE_ENTRYADDR ?= $(UIMAGE_LOADADDR)
354 UIMAGE_NAME ?= 'Linux-$(KERNELRELEASE) - OmniVision ASIC'
355 UIMAGE_IN ?= $<
356 UIMAGE_OUT ?= $@
357
358 quiet_cmd_uimage = UIMAGE $(UIMAGE_OUT)
359       cmd_uimage = $(CONFIG_SHELL) $(MKIMAGE) -A $(UIMAGE_ARCH) -O linux \
360             -C $(UIMAGE_COMPRESSION) $(UIMAGE_OPTS-y) \
361             -T $(UIMAGE_TYPE) \
362             -a $(UIMAGE_LOADADDR) -e $(UIMAGE_ENTRYADDR) \
363             -n $(UIMAGE_NAME) -d $(UIMAGE_IN) $(UIMAGE_OUT)

scripts/mkuboot.sh:

1 #!/bin/bash
2
3 #
4 # Build U-Boot image when `mkimage' tool is available.
5 #
6
7 MKIMAGE=$(type -path "${CROSS_COMPILE}mkimage")
8 if [ -z "${MKIMAGE}" ]; then
9     MKIMAGE=$(type -path mkimage)
10     if [ -z "${MKIMAGE}" ]; then
11         # Doesn't exist
12         echo '"mkimage" command not found - U-Boot images will not be built' >&2
13         exit 1;
14     fi
15 fi
16
17 # Call "mkimage" to create U-Boot image
18 ${MKIMAGE} "$@"