Inside XNU

Inside XNU Series

Inside XNU is a blog-series in which I analyse and discuss the boot process and functionality of the XNU Kernel, and particular stages of iBoot. My inspiration for this project comes from the Linux Insides book by @0xAX where he covers different areas of the Linux Kernel in quite some detail. I’d like to do the same, as there is no real equivalent for XNU with exception of Jonathan Levin’s books. I aim to cover the Kernel and iBoot in a series of blog-posts, with each focusing on a particular area. The coverage of iBoot will be brief, and focus primarily on the Tasking system and loading of the Kernel.

We will be looking at XNU from an ARM64 point of view, as that is the architecture I am most familiar with, although I may point out interesting cross-platform items.

In terms of the timeframe for these posts, I do not want to commit to a set timetable as I have other commitments I must meet first. I’d like to do 2-3 per month, and if and when I have the time I shall do more. I’d also like to mention that I am in no way an expert on this subject. I have taken up OS development as a hobby and have a significant interest in the operation and development of Kernel’s - particularly iOS.

My hobby OS, that I am working on with nullpixel of the checkra1n team, is currently private. However, we do plan to open-source it in the future.

Contents

iBoot

XNU Kernel