[开发工具] 从零开始使用Vscode调试XV6

sudo apt install binutils-riscv64-linux-gnu
sudo apt install gcc-riscv64-linux-gnu
sudo apt install gdb-multiarch
sudo apt install qemu-system-misc u-boot-qemu qemu-utils

报错：

a725@ubuntu:~/Desktop/xv6/xv6-riscv$ make qemu
qemu-system-riscv64 -machine virt -bios none -kernel kernel/kernel -m 128M -smp 1 -nographic -drive file=fs.img,if=none,format=raw,id=x0 -device virtio-blk-device,drive=x0,bus=virtio-mmio-bus.0
make: qemu-system-riscv64: Command not found
Makefile:164: recipe for target 'qemu' failed
make: *** [qemu] Error 127

解决方案：
  249  wget https://download.qemu.org/qemu-5.1.0.tar.xz
  251  tar -xvf qemu-5.1.0.tar.xz 
  253  cd qemu-5.1.0/
  275  ./configure --target-list=riscv64-softmmu,riscv64-linux-user
  276  sudo make -j8
  277  sudo make install


然后终端 输入 qemu-system-risv6 --version能打印即算ok

看到shell即代表ok

a725@ubuntu:~/Desktop/xv6/xv6-riscv$ make qemu
qemu-system-riscv64 -machine virt -bios none -kernel kernel/kernel -m 128M -smp 1 -nographic -drive file=fs.img,if=none,format=raw,id=x0 -device virtio-blk-device,drive=x0,bus=virtio-mmio-bus.0

xv6 kernel is booting

init: starting sh
$ ls
.              1 1 1024
..             1 1 1024
README         2 2 2226
cat            2 3 23896
echo           2 4 22720
forktest       2 5 13016
grep           2 6 27256
init           2 7 23816
kill           2 8 22696
ln             2 9 22648
ls             2 10 26144
mkdir          2 11 22800
rm             2 12 22784
sh             2 13 41792
stressfs       2 14 23792
usertests      2 15 156240
grind          2 16 37992
wc             2 17 25000
zombie         2 18 22168
console        3 19 0
$

退出方法

在 xv6 中按?Ctrl?+?a?，然后按?x?即可退出 xv6 系统。

?2.compile_commands.json生成：便于调试

makefile的生成方法：安装compiledbhttps://github.com/nickdiego/compiledb.git

针对makefile:? ?安装compiledb【git clone https://github.com/nickdiego/compiledb.git】来自动生成compile_commands.json

sudo python3 setup.py install
将sh-completion/compiledb.bash文件的内容添加到.bashrc文件中。
然后在 xv6目录下 compiledb make 即可?，可看到生成的 compile_commands.json?

Cmake的生成方法

如果用CMAKE，加上参数DCMAKE_EXPORT_COMPILE_COMMANDS即可生成
cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=True ..

3. xv6的Makefile修改

修改xv6文件夹的Makefie 的 -smp 为1 便于调试
看Makefile来理解整个kernel的编译过程

make | less 或者 make | vim -

Makefile的宏定义不能定义到 vscode

bear make ,让 vscode的宏生效

关于? .gdbinit

gdb里面又gdb intit的配置，避免重复输入命令

4. 调试内核

开两个Terminal?

此时,在xv6-riscv目录下,执行make qemu-gdb?,进程会阻塞.

另开一个终端,在xv6-riscv目录下,执行gdb-multiarch kernel/kernel

?配置.gdbinit让其在gdb启动的时候生效

?按上图红色部分修改

5. 在vscode调试

配置tasks.json--->Terminal--->configure default build tasak


{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "xv6build",
            "type": "shell",
            "isBackground": true,
            "command": "make qemu-gdb",
            "problemMatcher": [
                {
                    "pattern": [
                        {
                            "regexp": ".",
                            "file": 1,
                            "location": 2,
                            "message": 3
                        }
                    ],
                    "background": {
                        "beginsPattern": ".*Now run 'gdb' in another window.",
                        "endsPattern": "."
                    }
                }
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

配置launch.json[用于调试]

注意：由于有?"miDebuggerServerAddress": "127.0.0.1:26000", //所以需要吧.gdbinit 中 target remote xxxx:xx改为

@REM?target remote xxxx:xx

// xv6-riscv/.vscode/launch.json
{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "xv6debug",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/kernel/kernel",
            "stopAtEntry": true,
            "cwd": "${workspaceFolder}",
            "miDebuggerServerAddress": "127.0.0.1:26000", //见.gdbinit 中 target remote xxxx:xx
            "miDebuggerPath": "/usr/bin/gdb-multiarch", // which gdb-multiarch
            "MIMode": "gdb",
            "preLaunchTask": "xv6build"
        }
    ]
}