VS Code 调试 start.S 汇编代码

特别注意：debug时候，CFLAGS  AFLAGS  一定要加入 -g 参数。

CFLAGS += -O0 -gdwarf-2
AFLAGS += -gdwarf-2

 VS Code中加入汇编断点：

在右侧 Run and Debug窗口的BREAKPOINTS，加入汇编的lable，如_boot、_start

https://gitee.com/rtthread/rt-thread 

rt-thread/.vscode/launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(gdb) Launch",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/bsp/raspberry-pi/raspi3-64/rtthread.elf",
            "args": [],
            "stopAtEntry": true,
            "cwd": "${workspaceFolder}/bsp/raspberry-pi/raspi3-64",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "targetArchitecture": "arm",
            "miDebuggerPath":"/usr/bin/gdb-multiarch",  // "/opt/gcc-arm-10.3-2021.07-x86_64-aarch64-none-elf/bin/aarch64-none-elf-gdb"
            "miDebuggerServerAddress": "localhost:1234",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ]
        }
    ]
}

当gdb启动时，会读取HOME目录和当前目录下的的配置文件，执行里面的命令。这个文件通常为“.gdbinit”。

所以 .gdbinit需要在 "cwd": "${workspaceFolder}/bsp/raspberry-pi/raspi3-64",目录下

rt-thread/bsp/raspberry-pi/raspi3-64/.gdbinit

# set architecture aarch64
# target remote localhost:1234
# file rtthread.elf
# layout asm
b main
b *0x80000
b *0x80088

How to debug with gdb

Append -s and -S options to the qemu command.

• -s: enable to attach gdb to QEMU at port 1234
• -S: start and halted CPU (wait for attach from gdb)

VS Code 打开任何C/C++文件，右键选择  Open Disassembly View

https://docs.lagerdata.com/tutorials/vscode.html

https://github.com/Microsoft/vscode-cpptools/issues/1498

https://github.com/microsoft/vscode-cpptools/issues/6010

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(arm-none-eabi-gdb) Launch",
            "type": "cppdbg",
            "request": "launch",
            "miDebuggerPath":"/usr/bin/gdb-multiarch",
            "targetArchitecture": "arm",
            "program": "${workspaceFolder}/kernel.elf",
            "setupCommands": [
                {"text": "set remotetimeout 5"},
                {"text": "target remote localhost:1234"},
                {"text": "monitor reset halt"},
                {"text": "file kernel.elf"},
                {"text": "load"},
                {"text": "break main thread 1","ignoreFailures": true},
            ],
            "launchCompleteCommand": "None",
            "externalConsole": false,
            "cwd": "${workspaceFolder}",
        }
    ]
}

不确定是否是QEMU的bug ？

使用 img 二进制文件时，QEMU调试boot启动代码， mrs x0, CurrentEL，x0=8:  EL2

qemu-system-aarch64 -M raspi3 -m 1024 -serial null -serial mon:stdio -nographic -kernel kernel.img -S -s

使用 elf 文件时，QEMU调试boot启动代码， mrs x0, CurrentEL，x0=12:  EL3

qemu-system-aarch64 -M raspi3 -m 1024 -serial null -serial mon:stdio -nographic -kernel kernel.elf -S -s

其他：

.gdbinit用法示例

aarch64-none-elf-gdb -x .gdbinit -tui

gdb 多核/多线程

b main thread 1

b *0x80000 thread 1