VSCode 调试 u-boot

调试配置

参考 qemu基础篇——VSCode 配置 GDB 调试

要想调试 u-boot 只需要再添加一个 u-boot 的配置即可

{"version": "0.2.0","configurations": [{// qemu 裸机调试配置"name": "qemu_bare","type": "cppdbg","request": "launch","program": "${workspaceFolder}/qemu_code/bare/example/0020_mmu/bsp.elf","args": [],"stopAtEntry": true,"cwd": "${workspaceFolder}/qemu_code/bare","environment": [],"externalConsole": false,"MIMode": "gdb","miDebuggerPath": "/home/tyustli/cross_tool/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf/bin/arm-none-linux-gnueabihf-gdb","miDebuggerServerAddress": "localhost:1234",},{   // u-boot 调试配置"name": "u-boot","type": "cppdbg","request": "launch","program": "${workspaceFolder}/open_source/u-boot/u-boot","args": [],"stopAtEntry": true,"cwd": "${workspaceFolder}/open_source/u-boot","environment": [],"externalConsole": false,"MIMode": "gdb","miDebuggerPath": "/home/tyustli/cross_tool/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf/bin/arm-none-linux-gnueabihf-gdb","miDebuggerServerAddress": "localhost:1234",},]
}

启动 u-boot 脚本

qemu-system-arm -M vexpress-a9 -m 256 -kernel ./u-boot -nographic -s -S

调试界面

重定向之后继续调试

需要注意的是，u-boot 有一段重定向代码，之后 VSCode 就不能调试了

u-boot/arch/arm/lib/crt0.S 重定向代码

	adr	lr, here
#if defined(CONFIG_POSITION_INDEPENDENT)adr	r0, _mainldr	r1, _start_ofsadd	r0, r1ldr	r1, =CONFIG_TEXT_BASEsub	r1, r0add	lr, r1
#if defined(CONFIG_SYS_RELOC_GD_ENV_ADDR)ldr	r0, [r9, #GD_ENV_ADDR]		/* r0 = gd->env_addr */add	r0, r0, r1str	r0, [r9, #GD_ENV_ADDR]
#endif
#endifldr	r0, [r9, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */add	lr, lr, r0
#if defined(CONFIG_CPU_V7M)orr	lr, #1				/* As required by Thumb-only */
#endifldr	r0, [r9, #GD_RELOCADDR]		/* r0 = gd->relocaddr */b	relocate_code

解决方法也比较简单

官网推荐的方法是 使用 gdb 命令行来手动加载符号表 。

add-symbol-file u-boot 重定位后的地址

重定位后的地址就位于 gd 中的成员变量 unsigned long relocaddr; 中。
从上面的代码中可以看到 ，地址就放在 R0 寄存器中。得到地址之后执行如下命令

-exec add-symbol-file /home/tyustli/code/open_source/u-boot/u-boot 0x6ff62000

就可以接着调试了。

参考

• https://blog.csdn.net/tyustli/article/details/133829652
• https://itexp.blog.csdn.net/article/details/122173518