Introduction Objectives Who You Are The Linux Foundation Linux Foundation Training Certification Programs and Digital Badging Linux Distributions Preparing Your System Things change in Linux Documentation and Links

Preliminaries Procedures Kernel Versions Kernel Sources and Use of git Hardware

How to Work in OSS Projects ** Overview on How to Contribute Properly Stay Close to Mainline for Security and Quality Study and Understand the Project DNA Figure Out What Itch You Want to Scratch Identify Maintainers and Their Work Flows and Methods Get Early Input and Work in the Open Contribute Incremental Bits, Not Large Code Dumps Leave Your Ego at the Door: Don’t Be Thin-Skinned Be Patient, Develop Long Term Relationships, Be Helpful

Cross-Development Toolchain The Compiler Triplet Built-in Linux Distribution Cross Compiler Linaro CodeSourcery crosstool-ng Buildroot OpenEmbedded Yocto Project Labs

QEMU What is QEMU? Emulated Architectures Image Formats Why use QEMU? Labs

Booting a Target Development Board from uSD Why do we use uSD cards? Getting SW onto a uSD card Why is using uSD cards a bad idea? Labs

Booting a Target Development Board over Ethernet Using virtual Hardware An easier way to develop Objectives of the Lab Labs

Kernel Configuration, Compilation, Booting Configuring the Kernel for the Development Board Labs

Device Drivers Types of Devices Mechanism vs. Policy Avoiding Binary Blobs Power Management How Applications Use Device Drivers Walking Through a System Call Accessing a Device Error Numbers printk() devres: Managed Device Resources Labs

Modules and Device Drivers The module_driver() Macros Modules and Hot Plug Labs

Memory Management and Allocation Virtual and Physical Memory Memory Zones Page Tables kmalloc() __get_free_pages() vmalloc() Slabs and Cache Allocations Labs

Character Devices Device Nodes Major and Minor Numbers Reserving Major/Minor Numbers Accessing the Device Node Registering the Device udev dev_printk() and Associates file_operations Structure Driver Entry Points The file and inode Structures Miscellaneous Character Drivers Labs

Kernel Features Components of the Kernel User-Space vs. Kernel-Space What are System Calls? Available System Calls Scheduling Algorithms and Task Structures Process Context Labs

Transferring Between User and Kernel Space Transferring Between Spaces put(get)_user() and copy_to(from)_user() Direct Transfer: Kernel I/O and Memory Mapping Kernel I/O Mapping User Pages Memory Mapping User-Space Functions for mmap() Driver Entry Point for mmap() Accessing Files from the Kernel Labs

Platform Drivers What are Platform Drivers? Main Data Structures Registering Platform Devices An Example Hardcoded Platform Data The New Way: Device Trees Labs

Device Trees What are Device Trees? What Device Trees Do and What They Do Not Do Device Tree Syntax Device Tree Walk Through Device Tree Bindings Device Tree support in Boot Loaders Using Device Tree Data in Drivers Coexistence and Conversion of Old Drivers Labs

Interrupts and Exceptions What are Interrupts and Exceptions? Exceptions Asynchronous Interrupts MSI Enabling/Disabling Interrupts What You Cannot Do at Interrupt Time IRQ Data Structures Installing an Interrupt Handler Labs

Timing Measurements Kinds of Timing Measurements Jiffies Getting the Current Time Clock Sources Real Time Clock Programmable Interval Timer Time Stamp Counter HPET Going Tickless

Kernel Timers Inserting Delays What are Kernel Timers? Low Resolution Timer Functions Low Resolution Timer Implementation High Resolution Timers Using High Resolution Timers Labs

ioctls What are ioctls? Driver Entry point for ioctls Defining ioctls Labs

Unified Device Model and sysfs Unified Device Model Basic Structures Real Devices sysfs kset and kobject examples Labs

Sleeping and Wait Queues What are Wait Queues? Going to Sleep and Waking Up Going to Sleep Details Exclusive Sleeping Waking Up Details Polling Labs

Interrupt Handling: Deferrable Functions and User Drivers Top and Bottom Halves Softirqs Tasklets Work Queues New Work Queue API Creating Kernel Threads Threaded Interrupt Handlers Interrupt Handling in User-Space Labs

Hardware I/O Memory Barriers Allocating and Mapping I/O Memory Accessing I/O Memory

Direct Memory Access (DMA)** What is DMA? DMA Directly to User DMA and Interrupts DMA Memory Constraints DMA Masks DMA API DMA Pools Scatter/Gather Mappings Labs

Memory Technology Devices (Flash Memory Filesystems) What are MTD Devices? NAND vs. NOR vs. eMMC Driver and User Modules Flash Filesystems

USB Drivers What is USB? USB Topology Terminology Endpoints Descriptors USB Device Classes USB Support in Linux Registering USB Device Drivers Moving Data Example of a USB Driver Labs

Closing and Evaluation Survey Evaluation Survey

Appendices — Booting the Target Development Board from uSD Objectives of the Lab Labs

Kernel Architecture I UNIX and Linux ** Monolithic and Micro Kernels Object-Oriented Methods Main Kernel Tasks User-Space and Kernel-Space

Kernel Programming Preview Task Structure Memory Allocation Transferring Data between User and Kernel Spaces Linked Lists Jiffies Labs

Modules What are Modules? A Trivial Example Compiling Modules Modules vs Built-in Module Utilities Automatic Loading/Unloading of Modules Module Usage Count Module Licensing Exporting Symbols Resolving Symbols ** Labs

Kernel Architecture II Processes, Threads, and Tasks Kernel Preemption Real Time Preemption Patch Labs

Kernel Configuration and Compilation Installation and Layout of the Kernel Source Kernel Browsers Kernel Configuration Files Kernel Building and Makefiles initrd and initramfs Labs

Kernel Style and General Considerations Coding Style Using Generic Kernel Routines and Methods Making a Kernel Patch sparse Using likely() and unlikely() Writing Portable Code, CPU, 32/64-bit, Endianness Writing for SMP Writing for High Memory Systems Power Management Keeping Security in Mind Labs

Race Conditions and Synchronization Methods Concurrency and Synchronization Methods Atomic Operations Bit Operations Spinlocks Seqlocks Disabling Preemption Mutexes Semaphores Completion Functions Read-Copy-Update (RCU) Reference Counts Labs

Memory Addressing Virtual Memory Management Systems With and Without MMU and the TLB Memory Addresses High and Low Memory Memory Zones Special Device Nodes NUMA Paging Page Tables page structure Labs

Memory Allocation Requesting and Releasing Pages Buddy System Slabs and Cache Allocations Memory Pools kmalloc() vmalloc() Early Allocations and bootmem() Memory Defragmentation Labs