Android Kernel Debug

This document gives a way to debug Android kernel using Android emulator and ARM-LINUX-ANDROIDEABI-GDB

1. Checkout goldfish Source: Kernel used by the simulator is goldfish

git clone https://android.googlesource.com/kernel/goldfish.git gitcheckout-t origin/android-goldfish-3.4-b goldfish3.4

　　

2. Set environment variables, mainly to specify the cross compiler to path path: The following sentences can be saved as a script, need to execute in the shell

Export path= $YOUR _android_src_path/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.8/bin/: $PATHexport ARCH= Armexport Subarch=armexport Cross_compile=arm-eabi-make Goldfish_armv7_defconfig

3. Add kernel config option

The default Goldfish_armv7_defconfig configuration does not turn on debugging, nor does it use HIGHMEM, where we open the Goldfish/.config directory manually, opening several of the following configurations:

Config_highmem=y When this option is turned on, the emulator-memory parameter is activated when the emulator is started, or the emulator's memory is always more than 700 mconfig_debug_kernel=y when this option is turned on, vmlinux Only sign Config_kgdb=y open KGDB

　　

4. Start compiling

Make Arch=arm cross_compile= $YOUR _android_src_path/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.8/bin/ Arm-linux-androideabi-all

Since the 3rd step to open a few configurations, so the compile start will be prompted to choose configuration options, remember that the relevant configuration of all Y can be compiled after the goldfish/arch/arm/boot/zimage appear, this is the kernel

5. Start the simulator

Emulator-no-window-no-audio-verbose-show-kernel-kernel Goldfish/arch/arm/boot/zimage-memory 2048-qemu-s-S

　　

I generally debug the kernel does not require a graphical interface, so add-no-window, No-audio. In addition, want to see the detailed output of the kernel, add-show-kernel,-verbose, and then the-kernel parameter points to just compiled Zimage,-memory set memory, the larger the memory, debugging performance better, and finally-qemu-s-s Start debugging monitoring, that is, the kernel will wait on port 1234 after boot and not always start, this time need to start gdb in another interface:

Arm-linux-androideabi-gdb Goldfish/vmlinux

　　

Then perform remote debugging in the interface:

Reference:

https://gbrownmozilla.wordpress.com/2015/02/13/more-memory-for-the-android-emulator/

http://www.kgdb.info/kgdb/use_kgdb/using_kgdb_base_qemu/

Http://yabinc.blogspot.com/2015/03/build-and-run-android-linux-kernel-in.html

http://www.joenchen.com/archives/1093

Android Kernel Debug