uboot连接器脚本
来源:互联网 发布:软件与软件教育现代化 编辑:程序博客网 时间:2024/06/05 17:48
1、uboot.lds
- OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
- ;指定输出的格式,elf小端,32位
- OUTPUT_ARCH(arm)
- ;指定输出文件是arm平台
- ENTRY(_start)
- ;指定启始代码段为_start
- ;下面写的是链接,表示最终生成的elf格式,如何进行链接
- SECTIONS
- {
- . = 0x00000000;开始地址
- . = ALIGN(4);//4字节对齐
- .text ://正文段,即指令代码,放在当前位置,即0x00000000位置
- {
- cpu/arm920t/start.o (.text)//从目标文件start.o开始,即从汇编程序start.S开始
- *(.text)//其他代码部分都放在此处,如board.o cpu.o等等,在他们中有相应的跳转指令,只要指定开始就可以了
- //其他放在其后面,自己实现自动跳转。比如再编译c程序的时候,a.o b.o c.o最后生成a.out,只要指定开始就可以了
- //就是默认的main开始,其他的自己实现跳转,不用管放在什么位置了。
- }
- . = ALIGN(4);//继续4字节对齐
- .rodata : { *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) }只读代码段
- . = ALIGN(4);//继续4字节对齐
- .data : { *(.data) }//数据段,RW可读写
- . = ALIGN(4);//继续4字节对齐
- .got : { *(.got) }//自定义got段
- . = .;
- __u_boot_cmd_start = .;//定义变量__u_boot_cmd_start为当前位置
- .u_boot_cmd : { *(.u_boot_cmd) }//放置cmd
- __u_boot_cmd_end = .;定义变量__u_boot_cmd_end
- . = ALIGN(4);//继续4字节
- __bss_start = .;//定义__bss_start变量,为当前位置,定义为当前位置是因为不知道编译出来到有多大放
- //放到了那里,那么就等链接的时候自动生成并定义变量
- .bss (NOLOAD) : { *(.bss) . = ALIGN(4); }//bss段,即未初始化变量段如数组,参数等
- _end = .;//定义变量_end
- }
2、start.s
- #include <common.h>
- #include <config.h>
- /*
- *************************************************************************
- *
- * Jump vector table as in table 3.1 in [1]
- *
- *************************************************************************
- */
- .globl _start//这里定义了一个符号,_start 其中.globl指示告诉编译器,_start这个符号要被链接器用到,
- //_start就像C语言的main函数一样,告诉链接器程序从这里入口
- //每个汇编都要提供一个_start符号并且用.globl声明,如果使用默认到链接器。
- //如果一个符号没有被.globl声明,就表示这个符号不会被连接器用到。即使int a;声明没有赋值
- _start: b reset //符号具体含义的定义相当于对符号赋值 即a=....
- ldr pc, _undefined_instruction
- ldr pc, _software_interrupt
- ldr pc, _prefetch_abort
- ldr pc, _data_abort
- ldr pc, _not_used
- ldr pc, _irq
- ldr pc, _fiq
- _undefined_instruction: .word undefined_instruction//前面的_undefined_instruction也是一个符号,没有
- //globl声明不会被编译器用到。
- //把undefined_instruction值按照16bit赋值给
- //标号_undefined_instruction 即使int a=22;
- _software_interrupt: .word software_interrupt
- _prefetch_abort: .word prefetch_abort
- _data_abort: .word data_abort
- _not_used: .word not_used
- _irq: .word irq
- _fiq: .word fiq
- .balignl 16,0xdeadbeef
- /*
- *************************************************************************
- *
- * Startup Code (called from the ARM reset exception vector)
- *
- * do important init only if we don't start from
- * relocate armboot to ram
- * setup stack
- * jump to second stage
- *
- *************************************************************************
- */
- _TEXT_BASE:
- .word TEXT_BASE//定义符号_TEXT_BASE值为TEXT_BASE
- .word _start
- /*
- * These are defined in the board-specific linker script.
- */
- .globl _bss_start
- _bss_start:
- .word __bss_start//在lds中定义的开始赋值为_bss_start
- .globl _bss_end//同上//定义_bss_end为lds中的_end
- _bss_end:
- .word _end
- //下面这里没有define
- #ifdef CONFIG_USE_IRQ
- /* IRQ stack memory (calculated at run-time) */
- .globl IRQ_STACK_START
- IRQ_STACK_START:
- .word 0x0badc0de
- /* IRQ stack memory (calculated at run-time) */
- .globl FIQ_STACK_START
- FIQ_STACK_START:
- .word 0x0badc0de
- #endif
- //没有define
- /*
- * the actual start code
- */
- start_code:
- /*
- * set the cpu to SVC32 mode
- */
- mrs r0, cpsr//cpsr到r0
- bic r0, r0, #0x1f//
- orr r0, r0, #0xd3//上面把r0的32位赋值成SVC32模式然后下面再赋值给cpsr,改变状态寄存器从而进入svc32
- msr cpsr,r0
- bl coloured_LED_init//跳转到LED程序,这里可以删除,也可以进行点灯调试
- bl red_LED_on
- #if defined(CONFIG_AT91RM9200DK) || defined(CONFIG_AT91RM9200EK)
- /*
- * relocate exception table
- */
- //重新拷贝异常向量表,从_start开始的16个32位数据拷贝到0地址
- ldr r0, =_start
- ldr r1, =0x0
- mov r2, #16
- copyex:
- subs r2, r2, #1
- ldr r3, [r0], #4
- str r3, [r1], #4// 拷贝然后地址+4 每个地址1个字节,4*8=32
- bne copyex
- #endif
- #if defined(CONFIG_S3C2400) || defined(CONFIG_S3C2410)
- /* turn off the watchdog */
- # if defined(CONFIG_S3C2400)//定义寄存器地址
- # define pWTCON 0x15300000
- # define INTMSK 0x14400008 /* Interupt-Controller base addresses */
- # define CLKDIVN 0x14800014 /* clock divisor register */
- #else
- # define pWTCON 0x53000000
- # define INTMSK 0x4A000008 /* Interupt-Controller base addresses */
- # define INTSUBMSK 0x4A00001C
- # define CLKDIVN 0x4C000014 /* clock divisor register */
- # endif
- ldr r0, =pWTCON 关闭看门狗
- mov r1, #0x0
- str r1, [r0]
- /*
- * mask all IRQs by setting all bits in the INTMR - default
- */
- mov r1, #0xffffffff//这里关闭中断
- ldr r0, =INTMSK
- str r1, [r0]
- # if defined(CONFIG_S3C2410)
- ldr r1, =0x3ff
- ldr r0, =INTSUBMSK
- str r1, [r0]
- # endif
- /* FCLK:HCLK:PCLK = 1:2:4 */
- /* default FCLK is 120 MHz ! */
- ldr r0, =CLKDIVN
- mov r1, #3
- str r1, [r0]
- #endif /* CONFIG_S3C2400 || CONFIG_S3C2410 */
- /*
- * we do sys-critical inits only at reboot,
- * not when booting from
- */
- #ifndef CONFIG_SKIP_LOWLEVEL_INIT//这里没有定义skip,跳转到cpu_init_crit
- bl cpu_init_crit
- #endif
- //在lowlevel_init.S执行完后继续执行下面的代码
- #ifndef CONFIG_SKIP_RELOCATE_UBOOT //进行代码搬运
- relocate: /* relocate U-Boot to RAM */
- adr r0, _start /* r0 <- current position of code */ //adr取变脸地址,取_start地址。
- ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
- cmp r0, r1 /* don't reloc during debug */
- beq stack_setup
- ldr r2, _armboot_start //计算代码段大小 从_bss_start - _armboot_start即_start 都在lds中定义
- ldr r3, _bss_start
- sub r2, r3, r2 /* r2 <- size of armboot */ //然后从0地址拷贝这么大小的内容到_TEXT_BASE地址开始的空间中即内存
- add r2, r0, r2 /* r2 <- source end address */
- copy_loop:
- ldmia {r3-r10} /* copy from source address [r0] */
- stmia {r3-r10} /* copy to target address [r1] */
- cmp r0, r2 /* until source end addreee [r2] */
- ble copy_loop
- #endif /* CONFIG_SKIP_RELOCATE_UBOOT */
- /* Set up the stack */
- stack_setup: //这里初始化堆栈,搬运代码完成后,初始化堆栈
- ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */ //下面两个变量在Includes/config/smdk2410.h中有定义
- sub r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area */ //堆空间定义的大小 malloc可分配空间大小
- sub r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo */ //给内核传递参数的大小空间,初始化
- #ifdef CONFIG_USE_IRQ//这里不使用快速中断 下面不用
- sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
- #endif
- sub sp, r0, #12 /* leave 3 words for abort-stack */ //从这里看出初始化堆栈时间上就是给定sp寄存器的值
- clear_bss:
- ldr r0, _bss_start /* find start of bss segment */ //清楚_bss_start段为0
- ldr r1, _bss_end /* stop here */
- mov r2, #0x00000000 /* clear */
- clbss_l:str r2, [r0] /* clear loop... */
- add r0, r0, #4
- cmp r0, r1
- ble clbss_l
- ldr pc, _start_armboot //然后跳转到_start_armboot
- _start_armboot: .word start_armboot //lib_arm中board.c 程序中开始执行start_armboot函数 即传说中的stage2
- /*
- *************************************************************************
- *
- * CPU_init_critical registers
- *
- * setup important registers
- * setup memory timing
- *
- *************************************************************************
- */
- #ifndef CONFIG_SKIP_LOWLEVEL_INIT //初始化关键寄存器
- cpu_init_crit:
- /*
- * flush v4 I/D caches
- */
- mov r0, #0
- mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
- mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */ //初始化cache和快表
- /*
- * disable MMU stuff and caches
- */ //关闭MMU全部使用物理地址
- mrc p15, 0, r0, c1, c0, 0
- bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
- bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
- orr r0, r0, #0x00000002 @ set bit 2 (A) Align
- orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
- mcr p15, 0, r0, c1, c0, 0
- /*
- * before relocating, we have to setup RAM timing
- * because memory timing is board-dependend, you will
- * find a lowlevel_init.S in your board directory.
- */
- mov ip, lr
- bl lowlevel_init //跳转到board中的lowlevel_init.S中执行,进行SDARM的配置
- mov lr, ip
- mov pc, lr
- #endif /* CONFIG_SKIP_LOWLEVEL_INIT */
- /*
- *************************************************************************
- *
- * Interrupt handling
- *
- *************************************************************************
- */
- @
- @ IRQ stack frame.
- @
- #define S_FRAME_SIZE 72
- #define S_OLD_R0 68
- #define S_PSR 64
- #define S_PC 60
- #define S_LR 56
- #define S_SP 52
- #define S_IP 48
- #define S_FP 44
- #define S_R10 40
- #define S_R9 36
- #define S_R8 32
- #define S_R7 28
- #define S_R6 24
- #define S_R5 20
- #define S_R4 16
- #define S_R3 12
- #define S_R2 8
- #define S_R1 4
- #define S_R0 0
- #define MODE_SVC 0x13
- #define I_BIT 0x80
- /*
- * use bad_save_user_regs for abort/prefetch/undef/swi ...
- * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
- */
- .macro bad_save_user_regs
- sub sp, sp, #S_FRAME_SIZE
- stmia sp, {r0 - r12} @ Calling r0-r12
- ldr r2, _armboot_start
- sub r2, r2, #(CONFIG_STACKSIZE)
- sub r2, r2, #(CONFIG_SYS_MALLOC_LEN)
- sub r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
- ldmia r2, {r2 - r3} @ get pc, cpsr
- add r0, sp, #S_FRAME_SIZE @ restore sp_SVC
- add r5, sp, #S_SP
- mov r1, lr
- stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr
- mov r0, sp
- .endm
- .macro irq_save_user_regs
- sub sp, sp, #S_FRAME_SIZE
- stmia sp, {r0 - r12} @ Calling r0-r12
- add r7, sp, #S_PC
- stmdb r7, {sp, lr}^ @ Calling SP, LR
- str lr, [r7, #0] @ Save calling PC
- mrs r6, spsr
- str r6, [r7, #4] @ Save CPSR
- str r0, [r7, #8] @ Save OLD_R0
- mov r0, sp
- .endm
- .macro irq_restore_user_regs
- ldmia sp, {r0 - lr}^ @ Calling r0 - lr
- mov r0, r0
- ldr lr, [sp, #S_PC] @ Get PC
- add sp, sp, #S_FRAME_SIZE
- subs pc, lr, #4 @ return & move spsr_svc into cpsr
- .endm
- .macro get_bad_stack
- ldr r13, _armboot_start @ setup our mode stack
- sub r13, r13, #(CONFIG_STACKSIZE)
- sub r13, r13, #(CONFIG_SYS_MALLOC_LEN)
- sub r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
- str lr, [r13] @ save caller lr / spsr
- mrs lr, spsr
- str lr, [r13, #4]
- mov r13, #MODE_SVC @ prepare SVC-Mode
- @ msr spsr_c, r13
- msr spsr, r13
- mov lr, pc
- movs pc, lr
- .endm
- .macro get_irq_stack @ setup IRQ stack
- ldr sp, IRQ_STACK_START
- .endm
- .macro get_fiq_stack @ setup FIQ stack
- ldr sp, FIQ_STACK_START
- .endm
- /*
- * exception handlers
- */
- .align 5
- undefined_instruction:
- get_bad_stack
- bad_save_user_regs
- bl do_undefined_instruction
- .align 5
- software_interrupt:
- get_bad_stack
- bad_save_user_regs
- bl do_software_interrupt
- .align 5
- prefetch_abort:
- get_bad_stack
- bad_save_user_regs
- bl do_prefetch_abort
- .align 5
- data_abort:
- get_bad_stack
- bad_save_user_regs
- bl do_data_abort
- .align 5
- not_used:
- get_bad_stack
- bad_save_user_regs
- bl do_not_used
- #ifdef CONFIG_USE_IRQ
- .align 5
- irq:
- get_irq_stack
- irq_save_user_regs
- bl do_irq
- irq_restore_user_regs
- .align 5
- fiq:
- get_fiq_stack
- /* someone ought to write a more effiction fiq_save_user_regs */
- irq_save_user_regs
- bl do_fiq
- irq_restore_user_regs
- #else
- .align 5
- irq:
- get_bad_stack
- bad_save_user_regs
- bl do_irq
- .align 5
- fiq:
- get_bad_stack
- bad_save_user_regs
- bl do_fiq
- #endif
0 0
- uboot连接器脚本
- 连接器脚本
- 连接器脚本
- 连接器脚本
- 连接器脚本
- 连接器脚本
- 连接器脚本格式注意
- 连接器脚本详解
- 连接器脚本解析
- GNU Binutils 连接器默认链接节本脚本
- 连接器脚本 .bls bss data text stack
- 连接器
- uboot环境变量脚本
- uboot链接脚本
- uboot链接脚本
- uboot链接脚本分析
- uboot autoscript脚本
- uboot 如何运行脚本
- 博主发声:你期望的限免,告诉我们 (这不是广告,只是觉得不错,想分享给大家!)
- spark-sql 结合 hive
- 【系统安全】密码规则和登录限制
- Java8 学习笔记-stream-collection(2)
- HTTP/1.1的实体首部
- uboot连接器脚本
- 改错 字符串倒序
- Android 实现ListView的A-Z字母排序和过滤搜索功能,实现汉字转成拼音
- Island Perimeter
- java进行异常处理时的注意事项
- 移动前端开发之viewport的深入理解(总结)
- [leetcode]25. Reverse Nodes in k-Group
- RabbitMQ学习(二)---------请求许可
- Mybaits利用resultMap实现一对多