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The Linux Kernel Teaching Project

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View slides

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http://github.com/linux-kernel-labs

+

Octavian Purdila <tavi@cs.pub.ro>

+

Daniel Baluta <daniel.baluta@gmail.com>

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What is it?

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  • A collection of lectures and labs about Linux kernel topics
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  • The lectures focus on theoretical topics and Linux kernel +internals exploration
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  • The labs focus on device drivers topics and they resemble “howto” +style documentation
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  • Content based on the Operatings Systems 2 course from the Computer +Science and Engineering Department, the Faculty of Automatic +Control and Computers, University POLITEHNICA of Bucharest.
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What is it for?

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  • A base for people wanting to start learning about a specific +subsystem or a particular device driver
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  • A base for creating operating systems internals courses based on +the Linux kernel
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  • A base for creating traning courses on Linux kernel
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Lectures

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  • Present topics about Linux kernel internals as well as any +required OS internals concepts
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  • Topics: system calls, address space, SMP, interrupts, processes, +etc.
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Example: Introduction

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Labs

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The labs focus on device drivers topics and they resemble “howto” +style documentation. Each topic has two parts:

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  • a walk-through the topic which contains an overview, the main +abstractions, simple examples and pointers to APIs
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  • a hands-on part which contains a few exercises that should be +resolved by the student; to focus on the topic at hand, the +student is presented with a starting coding skeleton and with +in-depth tips on how to solve the exercises
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Example: Kernel Modules

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VM

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  • Exercises are designed to run on a qemu based virtual machine
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  • Lectures use gdb for introspection (e.g. follow system call flow)
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  • The virtual machine setup uses prebuild Yocto images that it +downloads from downloads.yocyoproject.org and a kernel image that +it builds itself
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  • Simulates typical Linux embedded development (e.g. students +connect to the VM via serial, simulates JTAG debugging via qemu +gdb support)
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VM demo

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Exercises

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  • Each lab has a hands-on exercises section which will contain +in-depth, incremental clues on how to solve one or multiple +tasks.
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  • To focus on a particular issue most of the tasks will be +performed on existing skeleton drivers.
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  • Each skeleton driver has clearly marked sections that needs to be +filled in order to complete the tasks
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  • The skeleton drivers are generated from full source examples +located in tools/labs/templates
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  • Targets for building and copying modules to VM image
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Exercises demo

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How?

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  • Integrated with the Linux kernel documentation system
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  • Uses a few extra sphinx plugins: hieroglyph, ditaa, ascinema
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  • Provides a qemu + yocto sandbox for kernel development as well as +iterative code templates
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Hieroglyph

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  • A sphinx plugin that creates HTML slides
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  • Same source for slides and docs
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+
Advocates of micro-kernels often suggest that micro-kernel are
+superior because of the modular design a micro-kernel
+enforces. However, monolithic kernels can also be modular and
+there are several approaches that modern monolithic kernels use
+toward this goal:
+
+.. slide:: Monolithic kernels *can* be modular
+   :level: 2
+   :inline-contents: True
+
+   * Components can enabled or disabled at compile time
+
+   * Support of loadable kernel modules (at runtime)
+
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+

Docs view +Slides view

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ditaa

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+
.. ditaa::
+
+   +---------------+  +--------------+      +---------------+  -\
+   | Application 1 |  | Application2 | ...  | Application n |   |
+   +---------------+  +--------------+      +---------------+   |> User space
+           |                 |                      |           |
+           v                 v                      v          -/
+   +--------------------------------------------------------+  -\
+   |                 System Call Interface                  |   |
+   +--------------------------------------------------------+   |
+
+
+../_images/ditaa-12614a4afe93c9e1ae68861a79f14afe4f3e4b3e.png +
+
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ascinema

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.. asciicast:: syscalls-inspection.cast
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Templates

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  • Full solution provided for exercises
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  • Script for generating skeletons from solution with simple +/* TODO <task>/<lines> */ annotations in the source code
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+
static void timer_handler(struct timer_list *tl)
+{
+  /* TODO 1/4: print a message */
+  static size_t nseconds;
+
+  nseconds += TIMER_TIMEOUT;
+  pr_info("[timer_handler] nseconds = %d\n", nseconds);
+
+  /* TODO 2: rechedule timer */
+  mod_timer(tl, jiffies + TIMER_TIMEOUT * HZ);
+}
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