Section qemu+gdb

gdb+qemu What a good thing , To practice this , Debug the kernel later , I won't print it .

qemu

First ：qemu To write a script ：
Name is runqemu

#!/bin/bash 
#SIMPLEVGA=1024x768-16:0x0df00000 /home/andy/loongson/qemu/qemu/mips64el-softmmu/qemu-system-mips64el -M ls2k -kernel vmlinux -m 2048 -smp 1 -append 'console=ttyS0, 115200 initcall_debug=1 loglevel=20 maxcpus=1 nomsix=1 nomsi=0 [email protected]' -dtb /home/andy/loongson/code/2k/pmon-loongson3/zloader.ls2k/LS2K.dtb -s -nographic -net nic -net user "[email protected]" # -initrd ./rootfs.cpio.gz
#SIMPLEVGA=1024x768-16:0x0df00000 /home/andy/loongson/qemu/qemu/mips64el-softmmu/qemu-system-mips64el -M ls2k -kernel vmlinux -m 2048 -smp 1 -append 'console=ttyS0, 115200 initcall_debug=1 loglevel=20 maxcpus=1 nomsix=1 nomsi=0 [email protected]' -dtb /home/andy/loongson/code/2k/pmon-loongson3/zloader.ls2k/LS2K.dtb -s -nographic -net nic -net user "[email protected]" # -initrd ./rootfs-pai2.cpio.gz
#SIMPLEVGA=1024x768-16:0x0df00000 /home/andy/loongson/qemu/qemu/mips64el-softmmu/qemu-system-mips64el -M ls2k -kernel vmlinux -m 2048 -smp 1 -append 'console=ttyS0, 115200 initcall_debug=1 loglevel=20 maxcpus=1 nomsix=1 nomsi=0 [email protected]' -dtb /home/andy/loongson/code/2k/pmon-loongson3/zloader.ls2k/LS2K.dtb -s -nographic -net nic -net user "[email protected]" # 
SIMPLEVGA=1024x768-16:0x0df00000 /home/andy/loongson/qemu/qemu/mips64el-softmmu/qemu-system-mips64el -M ls2k -kernel vmlinux -m 2048 -smp 1 -append 'console=ttyS0, 115200 initcall_debug=1 loglevel=20 maxcpus=1 nomsix=1 nomsi=0 [email protected]' -dtb /home/andy/loongson/code/loongson_pai/linux-4.19-loongson_new/linux-4.19.167-loongson/arch/mips/boot/dts/loongson/ls2k1000_pai_udb_v1_5.dtb -s -nographic -net nic -net user "[email protected]" # 

-M It corresponds to the name of the card for debugging . You can use ./qemu -d ? To view the supported boards .

-m Memory size

-smp Simulate several cores

-append Kernel boot pass parameters

-dtb dtb The path of

-s debugging （ Unknown ）

-nographic No graphics

./runqemu -S Step by step debugging . After running, it will be stuck in the first line

GDB

Suggest opening a tmux,qemu It's over there ./runqemu -S
gdb here gdb-multiarch vmlinux
Then enter gdb ,target remote 127.0.0.1:1234 Enter debugging .//qemu Created a
gdbserver, Use the command to establish a connection with the simulator's application

After that you can ctrl + x + o ,ctrl + x +2 Open the code box
Then you can officially debug
b To set breakpoints
c perform
n Single step non stepping function
s Single step but progressive function
frame 1 see Who called the current function （ Current function parent function ）
frame 2 View the grandfather of the current function
.....
wait .....

If there is no code box, no code is displayed ,list There is no code to show
Remember to add... When compiling +g colleagues menuconfig In the kernel hacking->config_debug_info
Choose