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标题: vmlinux.lds.S分析 [打印本页]

作者: yinjiangrong 时间: 2011-07-27 15:15
标题: vmlinux.lds.S分析
#include <asm-generic/vmlinux.lds.h>
#include <asm/thread_info.h>
#include <asm/memory.h>

OUTPUT_ARCH(arm)
ENTRY(stext)

#ifndef __ARMEB__
jiffies = jiffies_64;
#else
jiffies = jiffies_64 + 4;
#endif

SECTIONS
{
#ifdef CONFIG_XIP_KERNEL
. = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
#else
. = PAGE_OFFSET + TEXT_OFFSET;
#endif
.text.head : {
_stext = .; //表示什么意思
_sinittext = .;
*(.text.head) //*(.text.head)这个对应那些代码类容，怎么跟相关的文件建立联系的
}

.init : { /* Init code and data */
INIT_TEXT
_einittext = .;
__proc_info_begin = .;
*(.proc.info.init)
__proc_info_end = .;
__arch_info_begin = .;
*(.arch.info.init) //

*(.arch.info.init)怎么找到对应的类容
__arch_info_end = .;
__tagtable_begin = .;
*(.taglist.init)
__tagtable_end = .;
. = ALIGN(16);
__setup_start = .;
*(.init.setup)
__setup_end = .;
__early_begin = .;
*(.early_param.init)
__early_end = .;
__initcall_start = .;
INITCALLS
__initcall_end = .;
__con_initcall_start = .;
*(.con_initcall.init)
__con_initcall_end = .;
__security_initcall_start = .;
*(.security_initcall.init)
__security_initcall_end = .;
#ifdef CONFIG_BLK_DEV_INITRD
. = ALIGN(32);
__initramfs_start = .;
usr/built-in.o(.init.ramfs)
__initramfs_end = .;
#endif
. = ALIGN(4096);
__per_cpu_start = .;
*(.data.percpu)
*(.data.percpu.shared_aligned)
__per_cpu_end = .;
#ifndef CONFIG_XIP_KERNEL
__init_begin = _stext;
INIT_DATA
. = ALIGN(4096);
__init_end = .;
#endif
}

/DISCARD/ : { /* Exit code and data */
EXIT_TEXT
EXIT_DATA
*(.exitcall.exit)
#ifndef CONFIG_MMU
*(.fixup)
*(__ex_table)
#endif
}

.text : { /* Real text segment */
_text = .; /* Text and read-only data */
__exception_text_start = .;
*(.exception.text)
__exception_text_end = .;
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
#ifdef CONFIG_MMU
*(.fixup)
#endif
*(.gnu.warning)//怎么找到对应的类容
*(.rodata)
*(.rodata.*)
*(.glue_7)
*(.glue_7t)
*(.got) /* Global offset table */
}

RODATA

_etext = .; /* End of text and rodata section */

#ifdef CONFIG_XIP_KERNEL
__data_loc = ALIGN(4); /* location in binary */
. = PAGE_OFFSET + TEXT_OFFSET;
#else
. = ALIGN(THREAD_SIZE);
__data_loc = .;
#endif

.data : AT(__data_loc) {
__data_start = .; /* address in memory */

/*
   * first, the init task union, aligned
   * to an 8192 byte boundary.
   */
*(.data.init_task)

#ifdef CONFIG_XIP_KERNEL
. = ALIGN(4096);
__init_begin = .;
INIT_DATA
. = ALIGN(4096);
__init_end = .;
#endif

. = ALIGN(4096);
__nosave_begin = .;
*(.data.nosave)
. = ALIGN(4096);
__nosave_end = .;

/*
   * then the cacheline aligned data
   */
. = ALIGN(32);
*(.data.cacheline_aligned)

/*
   * The exception fixup table (might need resorting at runtime)
   */
. = ALIGN(32);
__start___ex_table = .;
#ifdef CONFIG_MMU
*(__ex_table)
#endif
__stop___ex_table = .;

/*
   * and the usual data section
   */
DATA_DATA
CONSTRUCTORS

_edata = .;
}
_edata_loc = __data_loc + SIZEOF(.data);

.bss : {
__bss_start = .; /* BSS */
*(.bss)
*(COMMON)
_end = .;
}
/* Stabs debugging sections. */
.stab 0 : { *(.stab) }
.stabstr 0 : { *(.stabstr) }
.stab.excl 0 : { *(.stab.excl) }
.stab.exclstr 0 : { *(.stab.exclstr) }
.stab.index 0 : { *(.stab.index) }
.stab.indexstr 0 : { *(.stab.indexstr) }
.comment 0 : { *(.comment) }
}

作者: fei1700 时间: 2011-07-27 22:43
说错请纠正
1. _stext = .; _stext从当前地址开始

2. *(.text.head)，我的代码是*(.head.text)，在include/linux/init.h中有很多section的宏

/* For assembly routines */
#define __HEAD .section ".head.text","ax"

这个段是定义汇编部分的在 arch/arm/kernel/head.S
__HEAD
ENTRY(stext)

3. *(.arch.info.init) 在arch/arm/include/asm/mach/arch.h
MACHINE_START每款CPU都有定义一个

/*
* Set of macros to define architecture features. This is built into
* a table by the linker.
*/
#define MACHINE_START(_type,_name) \
static const struct machine_desc __mach_desc_##_type \
__used \
__attribute__((__section__(".arch.info.init"))) = { \
.nr = MACH_TYPE_##_type, \
.name = _name,
#define MACHINE_END \
};

复制代码

作者: linyunxian 时间: 2011-07-28 11:11
本身来说，就是控制最终的代码不同符号，区块的 layout 。
另外，还添加了特定的一些符号以用于在代码里面引用。

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