[uboot学习笔记（一）]u-boot.lds文件分析

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/* * (C) Copyright 2002-2004 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA *//***********************************************************************uboot version: 2009.08*board version: freescale imx28*uboot flie   : u-boot.lds*uboot链接脚本 ，指定生成可执行文件的各个代码段链接地址及标号*path:  \board\freescale\mx28_evk\u-boot.lds**Makefile:*/config.mk-->/board/freescale/mx28_evk/config.mk-->*/board/freescale/mx28_evk/u-boot.lds**********************************************************************/OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")OUTPUT_ARCH(arm)        /*指定输出的平台arm*/ENTRY(_start)           /*指定uboot输出可执行文件起始代码段*/SECTIONS{    . = 0x00000000;     /*ld最终链接时候，会被-Ttext $(TEXT_BASE)更新*/                        /*生成的uboot.bin链接地址都是从TEXT_BASE开始*/                        /*uboot分两个阶段（flash/ram）             */                        /*flash阶段，程序实际从0地址开始执行，但程序的*/                        *链接地址是从TEXT_BASE开始,第一个阶段代码执行*/                        /*都是相对寻址，所以即使链接地址不对应执行地址也不会出错*/                        /*LDFLAGS += -Ttext $(TEXT_BASE) 定义在顶层目录的config.mk*/                        /*TEXT_BASE = 0x41008000 在board/freescale/mx28_evk/config.mk定义*/    . = ALIGN(4);       /*4字节对齐*/    .text :             /*定义代码段*/    {                   /*start.o链接在text段最前*/        cpu/arm926ejs/start.o   (.text)          *(.text)        /*其他.o文件链接在start.o后面*/    }    . = ALIGN(4);       /*只读数据段*/    .rodata : { *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) }    . = ALIGN(4);       /*数据段*/    .data : { *(.data) }    . = ALIGN(4);    .got : { *(.got) }    . = .;    __u_boot_cmd_start = .; /*uboot自定义命令存储段*/    .u_boot_cmd : { *(.u_boot_cmd) }    __u_boot_cmd_end = .;    . = ALIGN(4);    __bss_start = .;        /*bss段起始*/    .bss (NOLOAD) : { *(.bss) . = ALIGN(4); }    _end = .;               /*bss结束地址*/}
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