#UNPACKING GZ LINUX KERNEL SOURCES HOW TO#
#UNPACKING GZ LINUX KERNEL SOURCES INSTALL#
#UNPACKING GZ LINUX KERNEL SOURCES ANDROID#
#UNPACKING GZ LINUX KERNEL SOURCES CODE#
#UNPACKING GZ LINUX KERNEL SOURCES DOWNLOAD#

#UNPACKING GZ LINUX KERNEL SOURCES ANDROID#

To build the GKI kernel for the aarch64 architecture, check outĪn Android Common Kernel branch no earlier than Android 13 and To identify when you can use Kleaf to build a kernel, and build instructions andĪndroid 13 introduced building kernels with $ repo init -b common-android-mainline & repo sync.īuilding the kernel Building with Bazel (Kleaf) Note: For example, to switch toĬommon-android-mainline from your existing Repo checkout, Switching to a different branch is similar to initializing a branch the To be cloned fully (not shallow), which enables fast switching among them. TheĬommon kernel manifests (and most others) define the kernel git repository You can switch among different branches within one Repo checkout. Pixel 3 (blueline) Pixel 3 XL (crosshatch) Pixel 5a (barbet) Pixel 5 (redfin) Pixel 4a (5G) (bramble) The following table lists the BRANCH names for kernels available Using the repo approach ensures a correct sourceĭownload the sources for the appropriate branch: mkdir android-kernel & cd android-kernel repo init -u -b BRANCH repo sync Repositories, while others (for example, the common kernels) require only a single Some kernels (for example, the Pixel 3 kernels) require sources from multiple git

#UNPACKING GZ LINUX KERNEL SOURCES DOWNLOAD#

To download the sources, toolchain, and build scripts. The kernel trees contain the kernel sources and all tools to build The Android tree contains only prebuilt kernelīinaries. Note: The root of the kernel source checkout containsīuild/build.sh. You can acquire more recent kernel sources by usingĬonfiguration by running build/build.sh from the root of your Sources, building the kernel, and embedding the results into a system imageīuilt from the Android Open Source Project (AOSP). Instructions guide you through the process of selecting the right

#UNPACKING GZ LINUX KERNEL SOURCES CODE#

Extracting the kernel can be useful when you want to verify comments left by kernel code authors or are just curious to see how a particular function was compiled.This page details the process of building custom You can now search the objdump output for the address ffffffff81590df0 to find the disassmbled net_ipv4_path function: ffffffff81590df0: 55 push %rbpįfffffff81590df4: 48 83 ec 20 sub $0x20,%rspįfffffff81590df8: 48 89 5d e8 mov %rbx,-0x18(%rbp)įfffffff81590dfc: 4c 89 65 f0 mov %r12,-0x10(%rbp)įfffffff81590e00: 4c 89 6d f8 mov %r13,-0x8(%rbp)įfffffff81590e04: e8 77 9c 0c 00 callq 0xffffffff8165aa80Įxtracting the Linux kernel is relatively straightforward once you know what extract-vmlinux is and where to find it. Luckily, all the symbols and their starting address can be found in the file /boot/System.map-$(uname -r).įor example, let’s lookup the address of tcp_v4_do_rcv: $ sudo grep ' tcp_v4_do_rcv' /boot/System.map-3.2.0-29-virtual You’ll notice that there are no symbol names, so you can’t easily find the starting point for functions you want to examine. So, you’ve extracted the kernel and are now looking at the disassembled kernel.

Using the same directory structure as before: $ cd /tmp/kernel-extract/ There’s quite a bit of code, so piping the output to less is probably a good idea. Now that you have decompressed and extracted the kernel image, you can use objdump to disassemble it.

$ sudo /usr/src/kernels/$(uname -r)/scripts/extract-vmlinux vmlinuz-$(uname -r) > vmlinux $ sudo /usr/src/linux-headers-$(uname -r)/scripts/extract-vmlinux vmlinuz-$(uname -r) > vmlinux Now, run the extract-vmlinux script to extract the image. $ sudo cp /boot/vmlinuz-$(uname -r) /tmp/kernel-extract/ You can now use extract-vmlinux to decompress and extract the kernel image.Ī good first step is to create a temporary directory and copy the kernel image to it: $ mkdir /tmp/kernel-extract You will be able to find the extract-linux script at /usr/src/kernels/$(uname -r)/scripts/extract-vmlinux.

#UNPACKING GZ LINUX KERNEL SOURCES INSTALL#

On CentOS, install kernel-devel: $ sudo yum install kernel-devel You will be able to find the extract-linux script at /usr/src/linux-headers-$(uname -r)/scripts/extract-vmlinux. On Ubuntu, install linux-headers-$(uname -r): $ sudo apt-get install linux-headers-$(uname -r) If you are extracting a kernel installed from your operating system, you can install the extract-linux script with your package manager. It’s unlikely that the script will change, but to be safe you should use the extract-vmlinux script that is from the same source tree as your kernel. You can download the latest version from GitHub: $ wget -O extract-vmlinux

#UNPACKING GZ LINUX KERNEL SOURCES HOW TO#

It will cover the extract-vmlinux script, how to use objdump, and how to use /boot/System.map to locate functions and other symbols.Įxtracting the Linux kernel image (vmlinuz)įirst, you’ll need to get the extract-vmlinux script so that you can decompress and extract the Linux kernel image.

This blog post explains how to extract and disassemble a Linux kernel image.

Unpacking gz linux kernel sources