Kernel Recipes 2013 - Conditional boot

•

2 j'aime•1,851 vues

This document discusses various ways to customize a bootloader's behavior based on hardware properties detected at boot time. It presents options for tweaking Grub2 or Syslinux to select different boot options depending on characteristics like the CPU type, virtualization support, or whether the system is running in a hypervisor. Specific examples are provided of using Syslinux modules or Lua scripts to detect properties and adjust the kernel command line accordingly in order to boot different kernels optimized for the detected hardware.

Technologie

Kernel Recipes 24th September 2013 @Paris
Custom Booting

Back to the Future
● First presentation of HDT @ KR2012
● Does HDT can define a way to boot ?
– NO, just inspecting hardware with a cli/gui
● How can I make my system booting based on
hardware properties ?

Tweaking a Bootloader
● Only the bootloader can do this job
● Making the hardware detection ASAP
● Link between hw properties and boot
entry/option
● Anyone in the room for hacking grub2 ?

Syslinux
● Syslinux provides libs to get HW information
– CPU
– Memory
– PCI
– DMI
– ACPI
– VESA
– Included since 2009 (3.74)

Two ways to make it
● Creating specific COM32 modules
– like IFCPU
– Raw C code, compiled against syslinux
● Using LUA scripts
– Custom defined behaviors based on HW
properties

Ifcpu.c32
label ifcpu
com32 ifcpu.c32
append <cpu_features> -- boot_entry_1 -- boot_entry_2
label boot_entry_1
kernel vmlinuz_entry1
append ...
label boot_entry_2
kernel vmlinuz_entry2
append ...
cpu_features could be :
64: x86_64 compatible (lm)
hvm: hardware virtualization (hvm or svm)
pae : Physical Address Extension (PAE)
multicore: multi-core CPUs
smp : multi-processor system
hypervisor : Running under an hypervisor

Using LUA
DEFAULT lua
label lua
com32 lua.c32
append script.lua
pxelinux.cfg/default

Using LUA
-- Including other modules
package.path = package.path .. ";pxelinux.cfg/?.lua;isolinux/?.lua"
require("hypervisor")
-- Setting up the original options
append=""
-- Adjust them regarding the hypervisor detection
append=detect_hypervisor(append)
-- Booting the kernel
print("Booting with " .. append )
kernel = syslinux.loadfile("/vmlinuz")
initrd = syslinux.initramfs_init()
syslinux.initramfs_load_archive(initrd, "/core.gz");
syslinux.boot_it(kernel, initrd, append)
script.lua

Using LUA
function detect_hypervisor (append)
cpuflags = cpu.flags()
if ( string.match(cpuflags["flags.hypervisor"], "yes")) then
print ("Hypervisor detected");
append=append .. "nr_cpus=1"
else
append=append .. "whatever_you_want"
end
return append
end
hypervisor.lua

Thanks !
● IRC : erwan_taf on freenode
● Twitter : erwanaliasr1
● email : erwan.velu@enovance.com

Contenu connexe

Tendances

Buildroot and Yocto, the two leading embedded Linux buildsystems, have largely overlapping goals but vastly different implementations. Perhaps you’re familiar with either, and wonder how your daily job would change if you used the other. Luca will share insights he gained while managing projects with both tools, spending a lot of time in learning how to achieve the same goals in a different way. He will give a sort of “translation table” to ease the transition between the two, covering: bootstrapping a project, what happens under the hood, invoking the build, customizing the rootfs and tweaking recipes.

Luca Ceresoli - Buildroot vs Yocto: Differences for Your Daily Job

linuxlab_conf

linux minimal os tutorial - by shatrix

Sherif Mousa

The configuration language used by the Linux kernel, known as kconfig, has gained some traction in the community, and is increasingly used by third-party projects. The kconfig-frontends package aims at centralising the effort of keeping an up-to-date, out of the Linux source tree, packaging of the kconfig infrastructure, ready for use by third party projects. The state of the project will be presented: what has been done so far, and ideas on future evolutions. Some kconfig tips and tricks will also be demonstrated.

Kernel Recipes 2013 - kconfig-frontends, a packaging of the kconfig parser an...

Anne Nicolas

Hands on with embedded linux using zero hardware

Rajesh Sola

Building Embedded Linux

Sherif Mousa

Yocto - Embedded Linux Distribution Maker

Sherif Mousa

Uboot startup sequence

Houcheng Lin

OpenWRT guide and memo

家榮吳

Distro Recipes 2013: What’s new in gcc 4.8?

Anne Nicolas

Yocto: Treinamento em Português

Otavio Salvador

Arm device tree and linux device drivers

Houcheng Lin

U-Boot presentation 2013

Wave Digitech

Embedded Fest 2019. Wei Fu. Linux on RISC-V--Fedora and Firmware in practice

EmbeddedFest

Linux kernel booting

Ramin Farajpour Cami

Yocto project has been used at Open-RnD for building a number of IoT related products. The talk will go though the details of integration of Poky build system and OpenEmbedded layers into 3 projects carried out at Open-RnD: an antonomous parking space monitoring system a distributed 3D steroscopic image acquisition system a gadget for acquisition of metabolic parameters of professional athletes The presentation will approach to building software, automation and upstreaming of fixes. Open-RnD is a small software company from Łódź, Poland. We have started using Yocto/Poky in late 2013 as a better alternative to in-house build system. Since then, we have successfully implemented a number of projects based on Poky. The presentation will go through the details of 3 projects that cover a diverse range of applications: an autonomous parking space monitoring system (ParkEasily) a distributed 3D stereoscopic image acquisition system (Ros3D) a gadget for acquisition of metabolic parameters of professional athletes (Sonda) We only use widely available hardware platforms such as BeagleBone Black, Raspberry Pi, Wandboard or Gateworks GW5400 (not as widely used as the previous ones, but still fully supported), hence all the points made during presentation are directly applicable by professionals and hobbyists alike.

Yocto and IoT - a retrospective

Open-RnD

Many Linux developers and users know that Bootloader boots Linux Kernel which starts Userspace. But what is behind that? Linux Boot process is very similar to the Big Bang which happened in our world: from singularity to the whole beautiful Universe of running Linux processes. What do you think is a black hole equivalent in the Linux? Come to hear about all of that from an engineer who worked on a new processors and boards bringup, Linux boot process modifications and did boot time optimization many times.

Embedded Fest 2019. Руслан Биловол. Linux Boot: The Big Bang theory

EmbeddedFest

Marco Cavallini @ LinuxLab 2018 : Workshop Yocto Project, an automatic genera...

Marco Cavallini

Each processor/chip architecture has its own procedure to boot the kernel. It works with desgined partition layout and vendor specific firmwares/bootloaders in the boot partition. We can learn the related knowledge from the Raspbian image for Raspberry Pi, which is the board we can obtain easily. However, the diversity between the special booting procedures with specific firmwares/bootloaders increases the complexity for distribution maintainers. It will be great if there is a way to make it more generic that can be applied to most of the chip architectures/boards to boot up the system. After referring to some Linux distributions, we learned U-Boot may play a role in the solution. It splits the booting procedure into hardware specific and generic system parts. This helps distribution maintainers deploy the generic system with OSTree, including device trees. Let’s deep dive into this magic booting procedure!

A Journey to Boot Linux on Raspberry Pi

Jian-Hong Pan

Linux kernel system call

Ramin Farajpour Cami

Presentation at October SG Android Developer Meetup by Jeff Pang. Jeff Pang shows us how you can build your own Android Tablet using BeagleBone and a capacitive touch screen. BeagleBone is an $89 MSRP, credit-card-sized Linux computer that connects to the Internet and runs software such as Android 4.0 and Ubuntu. With plenty of I/O and processing power for real-time analysis provided by an AM335x 720MHz ARM® processor, BeagleBone can be complemented with cape plug-in boards to augment functionality.

Build Your Own Android Tablet

SGAndroidDevs

Tendances (20)

Luca Ceresoli - Buildroot vs Yocto: Differences for Your Daily Job

linux minimal os tutorial - by shatrix

Kernel Recipes 2013 - kconfig-frontends, a packaging of the kconfig parser an...

Hands on with embedded linux using zero hardware

Building Embedded Linux

Yocto - Embedded Linux Distribution Maker

Uboot startup sequence

OpenWRT guide and memo

Distro Recipes 2013: What’s new in gcc 4.8?

Yocto: Treinamento em Português

Arm device tree and linux device drivers

U-Boot presentation 2013

Embedded Fest 2019. Wei Fu. Linux on RISC-V--Fedora and Firmware in practice

Linux kernel booting

Yocto and IoT - a retrospective

Embedded Fest 2019. Руслан Биловол. Linux Boot: The Big Bang theory

Marco Cavallini @ LinuxLab 2018 : Workshop Yocto Project, an automatic genera...

A Journey to Boot Linux on Raspberry Pi

Linux kernel system call

Build Your Own Android Tablet

Similaire à Kernel Recipes 2013 - Conditional boot

MIPS-X

Zoltan Balazs

Android for Embedded Linux Developers

Opersys inc.

Path to Surfdroid

Paul Dutot IEng MIET MBCS CITP OSCP CSTM

Buildroot is a tool designed by embedded Linux developers to build embedded Linux systems using cross-compilation. It allows to build a cross-compilation toolchain (or re-use an existing one), a root filesystem image with applications and libraries, a kernel image and a bootloader image or any combination of these. Buildroot is typically used to create the embedded Linux systems of industrial systems based on the ARM, PowerPC or x86 architectures, by integrating multiple existing open-source components (kernel, base components, graphical libraries, networking applications, etc.) and in-house components specific to the embedded system. Many of the early embedded Linux developers are used to work with text editors such as Emacs or Vi. However, in the recent years, the major expansion of the embedded Linux platform has attracted many more developers that are more familiar with feature-full, integrated, and user-friendly development environments. To fulfill this need, Eclipse provides an excellent platform, especially with extensions such as CDT, the Autotools plugin, the multiple plugins from the Linux tools project, the Target Communication Framework, and more. As many embedded Linux developers use Buildroot to build their system, it sounded natural to provide an easy-to-use integration with Eclipse. To achieve that, we: Developed an Eclipse plugin that automatically registers the available Buildroot toolchains into Eclipse CDT. This allows application developers to transparently build their application, and then execute it and debug it on the embedded target platform directly within Eclipse. Created a specialized Eclipse version bundling all the useful existing plug-ins for embedded Linux developers: Eclipse CDT, our specialized Buildroot plugin, the Autotools plugin, Linux Tools plugins, etc. Through this talk, we would like to demonstrate how Eclipse has been extended to match the needs of embedded Linux developers, and we will perform a live demonstration of these capabilities using an ARM development platform for which Eclipse will help build, execute and debug applications.

EclipseCon Eu 2012 - Buildroot Eclipse Bundle : A powerful IDE for Embedded L...

melbats

Grub and dracut ii

plarsen67

Embedded Linux BSP Training (Intro)

RuggedBoardGroup

oSC-2023-Cross-Build.pdf

AdrianSchrter1

Beagleboard xm-setup

Premjith Achemveettil

The Deck by Phil Polstra GrrCON2012

Philip Polstra

Building

Satpal Parmar

Extending bhyve beyond FreeBSD guests - EuroBSDCon 2013

bsdvirt

NetBSD workshop

Jun Ebihara

Lightweight Virtualization with Linux Containers and Docker | YaC 2013

dotCloud

Lightweight Virtualization with Linux Containers and Docker I YaC 2013

Docker, Inc.

Polstra 44con2012

Philip Polstra

Hacking and Forensics on the Go - 44CON 2012

44CON

HDT: un outil de diagnostic matériel. Présentation de Hardware Detection Tool. HDT permet de réaliser une analyse fine de la configuration d’une machine x86 depuis un bootloader. La configuration du processeur, de la mémoire, des périphériques PCI, du mode VESA, … sont ainsi présenté dans une interface texte ressemblant a du ncurses. Une présentation de l’outil, des cas d’utilisations rééls ainsi qu’une démonstration seront réalisés.

Hardware Detection Tool

Anne Nicolas

An Introduction to RISC-V bootflow

Atish Patra

Presented at: Open Source 101 at Home Presented by: Veer Muchandi, Red Hat Inc Abstract: While everyone wants to do Containers and Kubernetes, they don’t know what they are getting into from Security perspective. This session intends to take you from “I don’t know what I don’t know” to “I know what I don’t know”. This helps you to make informed choices on Application Security. Kubernetes as a Container Platform is becoming a de facto for every enterprise. In my interactions with enterprises adopting container platform, I come across common questions: - How does application security work on this platform? What all do I need to secure? - How do I implement security in pipelines? - What about vulnerabilities discovered at a later point in time? - What are newer technologies like Istio Service Mesh bring to table? In this session, I will be addressing these commonly asked questions that every enterprise trying to adopt an Enterprise Kubernetes Platform needs to know so that they can make informed decisions.

Securing Applications and Pipelines on a Container Platform

All Things Open

Clear Containers is an Open Containers Initiative (OCI) “runtime” that launches an Intel VT-x secured hypervisor rather than a standard Linux container. An introduction of Clear Containers will be provided, followed by an overview of CNM networking plugins which have been created to enhance network connectivity using Clear Containers. More specifically, we will show demonstrations of using VPP with DPDK and SRIO-v based networks to connect Clear Containers. Pending time we will provide and walk through a hands on example of using VPP with Clear Containers. About the speaker: Manohar Castelino is a Principal Engineer for Intel’s Open Source Technology Center. Manohar has worked on networking, network management, network processors and virtualization for over 15 years. Manohar is currently an architect and developer with the ciao (clearlinux.org/ciao) and the clear containers (https://github.com/01org/cc-oci-runtime) projects focused on networking. Manohar has spoken at many Container Meetups and internal conferences.

Using VPP and SRIO-V with Clear Containers

Michelle Holley

Similaire à Kernel Recipes 2013 - Conditional boot (20)

MIPS-X

Android for Embedded Linux Developers

Path to Surfdroid

EclipseCon Eu 2012 - Buildroot Eclipse Bundle : A powerful IDE for Embedded L...

Grub and dracut ii

Embedded Linux BSP Training (Intro)

oSC-2023-Cross-Build.pdf

Beagleboard xm-setup

The Deck by Phil Polstra GrrCON2012

Building

Extending bhyve beyond FreeBSD guests - EuroBSDCon 2013

NetBSD workshop

Lightweight Virtualization with Linux Containers and Docker | YaC 2013

Lightweight Virtualization with Linux Containers and Docker I YaC 2013

Polstra 44con2012

Hacking and Forensics on the Go - 44CON 2012

Hardware Detection Tool

An Introduction to RISC-V bootflow

Securing Applications and Pipelines on a Container Platform

Using VPP and SRIO-V with Clear Containers

Plus de Anne Nicolas

Wanting to avoid the Android experience, Google developers always aimed to make their Chrome OS Linux kernels as close to mainline as possible. However, when Chromebooks were first created, Google was left with no choice, the mainline kernel, in some subsystems, still did not have all the functionalities needed by Chromebooks. Hence, similarly to Android, Chrome OS had to develop their own out-of-tree code for the kernel and maintain that for a few different kernel versions. Luckily, over the last few years a strong and consistent effort has been happening to bring Chromebook devices closer to mainline. It has led to significant improvements that now make it possible to run mainline on Chrome OS devices. And not only Chromebooks, as these significant strides are also improving Arm-based SOCs and other key components of the rich Chromebook hardware ecosystem. In this talk, we will look at how and why upstream support for Chromebooks improved, the current status of various models, and what we expect in the future. Enric Balletbò i Serra

Kernel Recipes 2019 - Driving the industry toward upstream first

Anne Nicolas

As the name would suggest, a Non-Maskable Interrupt (NMI) is an interrupt-like feature that is unaffected by the disabling of classic interrupts. In Linux, NMIs are involved in some features such as performance event monitoring, hard-lockup detector, on demand state dumping, etc… Their potential to fire when least expected can fill the most seasoned kernel hackers with dread. AArch64 (aka arm64 in the Linux tree) does not provide architected NMIs, a consequence being that features benefiting from NMIs see their use limited on AArch64. However, the Arm Generic Interrupt Controller (GIC) supports interrupt prioritization and masking, which, among other things, provides a way to control whether or not a set of interrupts can be signaled to a CPU. This talk will cover how, using the GIC interrupt priorities, we provide a way to configure some interrupts to behave in an NMI-like manner on AArch64. We’ll discuss the implementation, some of the complications that ensued and also some of the benefits obtained from it. Julien Thierry

Kernel Recipes 2019 - No NMI? No Problem! – Implementing Arm64 Pseudo-NMI

Anne Nicolas

At a rate of almost 9 changes per hour (24/7), the Linux kernel is definitely a scary beast. Bugs are introduced on a daily basis and, through the use of multiple code analyzers, *some* of them are detected and fixed before they hit mainline. Over the course of the last few years, Gustavo has been fixing such bugs and many different issues in every corner of the Linux kernel. Recently, he was in charge of leading the efforts to globally enable -Wimplicit-fallthrough; which appears by default in Linux v5.3. This presentation is a report on all the stuff Gustavo has found and fixed in the kernel with the support of the Core Infrastructure Initiative. Gustavo A.R. Silva

Kernel Recipes 2019 - Hunting and fixing bugs all over the Linux kernel

Anne Nicolas

Kernel Recipes 2019 - Metrics are money

Anne Nicolas

The Linux kernel project includes a huge amount of documentation, but that information has seen little in the way of care over the years. The amount of care has increased significantly recently, though, and things are improving quickly. Listen as the kernel’s documentation maintainer discusses the current state of the kernel’s docs, how we got here, where we’re trying to go, and how you can help. Jonathan Corbet

Kernel Recipes 2019 - Kernel documentation: past, present, and future

Anne Nicolas

Modern SoC designs incorporate technologies from numerous vendors, each with their own inconsistent, confusing, undocumented and even contradictory terminology. The result is a mess of acronyms and product names which have a surprising impact on the ability to develop reusable, modular code thanks to the nature of the underlying IP being obscured. This presentation will dive into some of the misnomers plaguing the Arm ecosystem, with the aim of explaining why things are like they are, how they fit together under the architectural umbrella and how you, as a developer, can decipher the baffling ingredients list of your next SoC design! Will Deacon

Embedded Recipes 2019 - Knowing your ARM from your ARSE: wading through the t...

Anne Nicolas

GNU poke is a new interactive editor for binary data. Not limited to editing basic ntities such as bits and bytes, it provides a full-fledged procedural, interactive programming language designed to describe data structures and to operate on them. Once a user has defined a structure for binary data (usually matching some file format) she can search, inspect, create, shuffle and modify abstract entities such as ELF relocations, MP3 tags, DWARF expressions, partition table entries, and so on, with primitives resembling simple editing of bits and bytes. The program comes with a library of already written descriptions (or “pickles” in poke parlance) for many binary formats. GNU poke is useful in many domains. It is very well suited to aid in the development of programs that operate on binary files, such as assemblers and linkers. This was in fact the primary inspiration that brought me to write it: easily injecting flaws into ELF files in order to reproduce toolchain bugs. Also, due to its flexibility, poke is also very useful for reverse engineering, where the real structure of the data being edited is discovered by experiment, interactively. It is also good for the fast development of prototypes for programs like linkers, compressors or filters, and it provides a convenient foundation to write other utilities such as diff and patch tools for binary files. This talk (unlike Gaul) is divided into four parts. First I will introduce the program and show what it does: from simple bits/bytes editing to user-defined structures. Then I will show some of the internals, and how poke is implemented. The third block will cover the way of using Poke to describe user data, which is to say the art of writing “pickles”. The presentation ends with a status of the project, a call for hackers, and a hint at future works. Jose E. Marchesi

Kernel Recipes 2019 - GNU poke, an extensible editor for structured binary data

Anne Nicolas

Operating system distributors often face challenges that are somewhat different from that of upstream kernel developers. For instance, some kernel updates often need to stay at least binary compatible with modules that might be “out of tree” for some time. In that context, being able to automatically detect and analyze changes to the binary interface exposed by the kernel to its module does have some noticeable value. The Libabigail framework is capable of analyzing ELF binaries along with their accompanying debug info in the DWARF format, detect and report changes in types, functions, variables and ELF symbols. It has historically supported that for user space shared libraries and application so we worked to make it understand the Linux kernel binaries. In this presentation, we are going to present the current support of ABI analysis for Linux Kernel binaries, the challenges we face, how we address them and the plans we have for the future. Dodji Seketeli, Jessica Yu, Matthias Männich

Kernel Recipes 2019 - Analyzing changes to the binary interface exposed by th...

Anne Nicolas

Different upgrade and update strategies exist when it comes to embedded Linux system. If at development time none of these strategies have been chosen, adding them afterwards can be tedious task. Even harder it gets when the system is already deployed in the field and only accessible via a 3G connection. This talk is a developer experience of putting in place exactly that. Giving a return of experience on one way of doing it on a system running Barebox and a Yocto-based distribution. Patrick Boettcher

Embedded Recipes 2019 - Remote update adventures with RAUC, Yocto and Barebox

Anne Nicolas

Traditionally graphics drivers were one of the last hold-outs of proprietary software in an embedded Linux system. This situation is changing with open-source graphics drivers showing up for almost all of the graphics acceleration peripherals on the market right now. This talk will show how open-source graphics drivers are making embedded systems less special, as well as trying to provide an overview of the Linux graphics stack, de-mystifying what is often seen as black magic GPU stuff from outside observers. Lucas Stach

Embedded Recipes 2019 - Making embedded graphics less special

Anne Nicolas

This talk will explore Open Source Hardware projects relevant to Linux, including boards like BeagleBone, Olimex OLinuXino, Giant board and more. Looking at the benefits and challenges of designing Open Source Hardware for a Linux system, along with BeagleBoard.org’s experience of working with community, manufacturers, and distributors to create an Open Source Hardware platform. In closing also looking at the future, Libre Silicon like RISC-V designs, and where this might take Linux. Drew Fustini

Embedded Recipes 2019 - Linux on Open Source Hardware and Libre Silicon

Anne Nicolas

The I2C subsystem is not the shiniest part of the Linux Kernel. For embedded devices, though, it is one of the many puzzle pieces which just have to work. Wolfram Sang has the experience of maintaining this subsystem for nearly 7 years now. This talk gives a short overview of how maintaining works in general and specifically in this subsystem. But mainly, it will highlight noteworthy points in the timeline and lessons learnt from that. It will present trends, not so much regarding I2C but more the Linux Kernel and the embedded ecosystem in general. And of course, there will be plenty of anecdotes and bits from behind the scenes for your entertainment. Wolfram Sang

Embedded Recipes 2019 - From maintaining I2C to the big (embedded) picture

Anne Nicolas

ITRenew is selling recertified OCP servers under the Sesame brand, those servers come either with their original UEFI BIOS or with LinuxBoot. The LinuxBoot project is pushing the Linux kernel inside bios flash and using userland programs as bootloader. To achieve quality on our software stack, as any project, we need to test it. Traditional BIOS are tested by hand, this is 2019 we need to do it automatically! We already presented the hardware setup behind the LinuxBoot CI, this talk will focus on the software. We use u-root for our userland bootloader; this software is written in Go so we naturally choose to use Go for our testing too. We will present how we are using and extending the Go native test framework `go test` for testing embedded systems (serial console) and improving the report format for integration to a CI. Julien Viard de Galbert

Embedded Recipes 2019 - Testing firmware the devops way

Anne Nicolas

About 60% of the Linux kernel source tree is devoted to drivers for a large variety of supported hardware components. Especially in the embedded world, the number of different SoC families, versions, and revisions, integrating a myriad of “IP cores”, keeps on growing. In this presentation, Geert will explain how to match drivers against hardware, and how to support a wide variety of (dis)similar devices, without turning platform and driver code into an entangled bowl of spaghetti.tra Starting with a brief history of driver matching in Linux, he will fast-forward to device-tree based matching. He will discuss ways to handle slight variations of the same hardware devices, and different SoC revisions, each with their own quirks and bugs. Finally, Geert will show best practices for evolving device drivers in a maintainable way, based on his experiences as an embedded Linux kernel developer and maintainer. Geert Uytterhoeven

Embedded Recipes 2019 - Herd your socs become a matchmaker

Anne Nicolas

Buildroot is a popular and easy to use embedded Linux build system. It generates, in few minutes, lightweight and customized Linux systems, including the cross-compilation toolchain, kernel and bootloader images, as well as a wide variety of userspace libraries and programs. This talk is about the integration of LLVM/clang into Buildroot. In 2018, Valentin Korenblit, supervised by Romain Naour, worked on this topic during his internship at Smile ECS. After a short introduction about llvm/clang and Buildroot, this talk will go through the numerous issues discovered while adding llvm/clang componants and how these issues were fixed. Romain will also detail the work in progress and the work to be done based on llvm/clang libraries (OpenCL, Compiler-rt, BCC. Chromium, ldd). Romain Naour

Embedded Recipes 2019 - LLVM / Clang integration

Anne Nicolas

This talk introduces JTAG debugging capabilities, both for debugging hardware and software. Marek first explains what the JTAG stands for and explains the operation of the JTAG state machine. This is followed by an introduction to free software JTAG tools, OpenOCD and urJTAG. Marek shortly explains how to debug software using those tools and how that ties into the JTAG state machine. However, JTAG was designed for testing hardware. Marek explains what boundary scan testing (BST) is, what are BSDL files and their format, and practically demonstrates how to blink an LED using BST and only free software tools. Marek Vasut

Embedded Recipes 2019 - Introduction to JTAG debugging

Anne Nicolas

PipeWire is an open source project that aims to greatly improve audio and video handling under Linux. Utilising a fresh design, it bridges use cases that have been previously addressed by different tools – or not addressed at all -, providing ground for building complex, yet secure and efficient, multimedia systems. In this talk, Julien is going to present the PipeWire project and the concepts that make up its design. In addition, he is going to give an update of the current and future work going on around PipeWire, both upstream and in Automotive Grade Linux, an early adopter that Julien is actively working on. Julian Bouzas

Embedded Recipes 2019 - Pipewire a new foundation for embedded multimedia

Anne Nicolas

Ftrace’s most powerful feature is the function tracer (and function graph tracer which is built from it). But to have this enabled on production systems, it had to have its overhead be negligible when disabled. As the function tracer uses gcc’s profiling mechanism, which adds a call to “mcount” (or more recently fentry, don’t worry if you don’t know what this is, it will all be explained) at the start of almost all functions, it had to do something about the overhead that causes. The solution was to turn those calls into “nops” (an instruction that the CPU simply ignores). But this was no easy feat. It took a lot to come up with a solution (and also turning a few network cards into bricks). This talk will explain the history of how ftrace came about implementing the function tracer, and brought with it the possibility of static branches and soon static calls! Steven Rostedt

Kernel Recipes 2019 - ftrace: Where modifying a running kernel all started

Anne Nicolas

Suricata is a network threat detection engine using network packets capture to reconstruct the traffic till the application layer and find threats on the network using rules that define behavior to detect. This task is really CPU intensive and discarding non interesting traffic is a solution to enable a scaling of Suricata to 40gbps and other. This talk will present the latest evolution of Suricata that knows uses eBPF and XDP to bypass traffic. Suricata 5.0 is supporting the hardware XDP to provide ypass with network card such as Netronome. It also takes advantage of pinned maps to get persistance of the bypassed flows. This talk will cover the different usage of XDP and eBPF in Suricata and shows how it impact performance and usability. If development time permit, the talk will also cover AF_XDP and the impact on this new capture method on Suricata. Eric Leblond

Kernel Recipes 2019 - Suricata and XDP

Anne Nicolas

System memory configuration is a transparent operation nowadays, something that we all came to expect to just work out of the box. Still, it does happen behind the scenes every single time we boot our computers. This requires the cooperation of hardware components on the mainboard and on memory modules themselves, as well as firmware code to drive these. While it is possible to just let it happen, having a deeper understanding of how it works makes it possible to access valuable information from the operating system at run-time. I will take you through the history of system memory configuration from the mid 70s to now. We will explore the different types of memory modules, how their configuration data is stored and how the firmware can access them. We will see which problems had to be solved along the way and how they were solved. Lastly we will see how Linux supports reading the memory configuration information and what you can do with that information. Jean Delvare

Kernel Recipes 2019 - Marvels of Memory Auto-configuration (SPD)

Anne Nicolas

Plus de Anne Nicolas (20)