Kernel Boot Process Kernel Booting Process. Part 1
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Device Tree 101
Device Tree 101 Device Tree 101 Organized in partnership with ST February 9, 2021 Thomas Petazzoni embedded Linux and kernel engineering [email protected] © Copyright 2004-2021, Bootlin. Creative Commons BY-SA 3.0 license. Corrections, suggestions, contributions and translations are welcome! - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 1/56 Who is speaking ? I Thomas Petazzoni I Chief Technical Officer at Bootlin I Joined in 2008, employee #1 I Embedded Linux & Linux kernel engineer, open-source contributor I Author of the Device Tree for Dummies talk in 2013/2014 I Buildroot co-maintainer I Linux kernel contributor: ≈ 900 contributions I Member of Embedded Linux Conference (Europe) program committee I Based in Toulouse, France - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 2/56 Agenda I Bootlin introduction I STM32MP1 introduction I Why the Device Tree ? I Basic Device Tree syntax I Device Tree inheritance I Device Tree specifications and bindings I Device Tree and Linux kernel drivers I Common properties and examples - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 3/56 Bootlin I In business since 2004 I Team based in France I Serving customers worldwide I 18% revenue from France I 44% revenue from EU except France I 38% revenue outside EU I Highly focused and recognized expertise I Embedded Linux I Linux kernel I Embedded Linux build systems I Activities -
Devicetree BOF
Devicetree BOF Open Source Summit Japan 2018 Tokyo Frank Rowand, Sony June 20, 2018 180618_0351 My Goal Do NOT show all of the slides Agenda - Past events - Future events - New since elc 2017 (February 2017) - Tools status - dtc compiler - questions, comments, issues, concerns from the crowd - commit statistics Plumbers 2017 Summary September 2017 Los Angeles Was not scheduled -- not enough interest / commitment Devicetree Workshop Oct 2017 Prague, Czech Republic https://elinux.org/Device_tree_future #Kernel_Summit_2017.2C_Devicetree_Workshop - slides - notes === Validation Tools & Schema === Runtime usage === DTS maintenance issues === More stuff Devicetree Workshop Oct 2017 Prague, Czech Republic Devicetree Workshop 2017 9:30 Welcome and Schedule bashing 9:40 Encoding and Schema checking: Framing the problem 9:45 DT YAML encoding overview 10:00 YAML encoding discussion 10:20 DT Schema format - option 1 10:35 DT Schema format - option 2 10:50 DT Schema discussion - what should go in the spec? 11:50 Code Generation from DT 12:10 Runtime memory consumption 14:30 Overlay maintenance plan 14:45 Avoiding duplicate descriptions 15:00 Criteria for accepting board files 15:15 Location for maintaining bindings - how to handle foreign bindings 15:30 Sharing Generic bindings 15:45 ABI Stability 16:00 [break and overflow discussion] 16:30 DT health check 16:50 devicetree.org update 17:05 EBBR Discussion 17:20 Closing and feedback Plumbers 2018 November 13 - 15, 2018 Tuesday - Thursday Vancouver, British Columbia, Canada https://www.linuxplumbersconf.org/event/2/overview -
Introduction to Linux Kernel Driver Programming
IntroductionIntroduction toto LinuxLinux kernelkernel driverdriver programmingprogramming Introduction to Linux kernel driver programming The Linux kernel device model Authors and license ● Authors – Michael Opdenacker ([email protected]) Founder of Bootlin, kernel and embedded Linux engineering company https://bootlin.com/company/staff/michael-opdenacker ● License – Creative Commons Attribution – Share Alike 4.0 https://creativecommons.org/licenses/by-sa/4.0/ – Document sources: https://github.com/e-ale/Slides Need for a device model ● For the same device, need to use the same device driver on multiple CPU architectures (x86, ARM…), even though the hardware controllers are different. ● Need for a single driver to support multiple devices of the same kind. ● This requires a clean organization of the code, with the device drivers separated from the controller drivers, the hardware description separated from the drivers themselves, etc. Driver: between bus infrastructure and framework In Linux, a driver is always interfacing with: ● a framework that allows the driver to expose the hardware features in a generic way. ● a bus infrastructure, part of the device model, to detect/communicate with the hardware. Let’s focus on the bus infrastructure for now Device model data structures The device model is organized around three main data structures: ● The struct bus_type structure, which represent one type of bus (USB, PCI, I2C, etc.) ● The struct device_driver structure, which represents one driver capable of handling certain devices on a certain bus. ● The struct device structure, which represents one device connected to a bus The kernel uses inheritance to create more specialized versions of struct device_driver and struct device for each bus subsystem. -
VAX MACRO and Instruction Set Reference Manual
VAX MACRO and Instruction Set Reference Manual Order Number: AA-LA89A-TE April 1988 This document describes the features of the VAX MACRO instruction set and assembler. It includes a detailed description of MACRO directives and instructions, as well as information about MACRO source program syntax. Revision/Update Information: This manual supersedes the VAX MACRO and Instruction Set Reference Manual, Version 4.0. Software Version: VMS Version 5.0 digital equipment corporation maynard, massachusetts April 1988 The information in this document is subject to change without notice and should not be construed as a commitment by Digital Equipment Corporation. Digital Equipment Corporation assumes no responsibility for any errors that may appear in this document. The software described in this document is furnished under a license and may be used or copied only in accordance with the terms of such license. No responsibility is assumed for the use or reliability of software on equipment that is not supplied by Digital Equipment Corporation or its affiliated companies. Copyright © 1988 by Digital Equipment Corporation All Rights Reserved. Printed in U.S.A. The postpaid READER'S COMMENTS form on the last page of this document requests the user's critical evaluation to assist in preparing future documentation. The following are trademarks of Digital Equipment Corporation: DEC DIBOL UNIBUS DEC/CMS EduSystem VAX DEC/MMS IAS VAXcluster DECnet MASSBUS VMS DECsystem-10 PDP VT DECSYSTEM-20 PDT DECUS RSTS DECwriter RSX t:JD~DD5lD TM ZK4515 HOW TO ORDER ADDITIONAL DOCUMENTATION DIRECT MAIL ORDERS USA 8t PUERTO Rico* CANADA INTERNATIONAL Digital Equipment Corporation Digital Equipment Digital Equipment Corporation P.O. -
Kernel Boot-Time Tracing
Kernel Boot-time Tracing Linux Plumbers Conference 2019 - Tracing Track Masami Hiramatsu <[email protected]> Linaro, Ltd. Speaker Masami Hiramatsu - Working for Linaro and Linaro members - Tech Lead for a Landing team - Maintainer of Kprobes and related tracing features/tools Why Kernel Boot-time Tracing? Debug and analyze boot time errors and performance issues - Measure performance statistics of kernel boot - Analyze driver init failure - Debug boot up process - Continuously tracing from boot time etc. What We Have There are already many ftrace options on kernel command line ● Setup options (trace_options=) ● Output to printk (tp_printk) ● Enable events (trace_events=) ● Enable tracers (ftrace=) ● Filtering (ftrace_filter=,ftrace_notrace=,ftrace_graph_filter=,ftrace_graph_notrace=) ● Add kprobe events (kprobe_events=) ● And other options (alloc_snapshot, traceoff_on_warning, ...) See Documentation/admin-guide/kernel-parameters.txt Example of Kernel Cmdline Parameters In grub.conf linux /boot/vmlinuz-5.1 root=UUID=5a026bbb-6a58-4c23-9814-5b1c99b82338 ro quiet splash tp_printk trace_options=”sym-addr” trace_clock=global ftrace_dump_on_oops trace_buf_size=1M trace_event=”initcall:*,irq:*,exceptions:*” kprobe_event=”p:kprobes/myevent foofunction $arg1 $arg2;p:kprobes/myevent2 barfunction %ax” What Issues? Size limitation ● kernel cmdline size is small (< 256bytes) ● A half of the cmdline is used for normal boot Only partial features supported ● ftrace has too complex features for single command line ● per-event filters/actions, instances, histograms. Solutions? 1. Use initramfs - Too late for kernel boot time tracing 2. Expand kernel cmdline - It is not easy to write down complex tracing options on bootloader (Single line options is too simple) 3. Reuse structured boot time data (Devicetree) - Well documented, structured data -> V1 & V2 series based on this. Boot-time Trace: V1 and V2 series V1 and V2 series posted at June. -
Devicetree Specification
Devicetree Specification Release unknown-rev devicetree.org unknown-rev 13 September 2021 Contents 1 Introduction 3 1.1 Purpose and Scope..............................................3 1.2 Relationship to IEEE™ 1275 and ePAPR..................................4 1.3 32-bit and 64-bit Support...........................................4 1.4 Definition of Terms..............................................4 2 The Devicetree 6 2.1 Overview...................................................6 2.2 Devicetree Structure and Conventions....................................7 2.2.1 Node Names............................................7 2.2.2 Generic Names Recommendation.................................8 2.2.3 Path Names............................................. 10 2.2.4 Properties.............................................. 10 2.3 Standard Properties.............................................. 12 2.3.1 compatible............................................. 12 2.3.2 model................................................ 13 2.3.3 phandle............................................... 13 2.3.4 status................................................ 14 2.3.5 #address-cells and #size-cells.................................... 14 2.3.6 reg.................................................. 15 2.3.7 virtual-reg.............................................. 15 2.3.8 ranges................................................ 15 2.3.9 dma-ranges.............................................unknown-rev 16 2.3.10 dma-coherent........................................... -
Device Tree the Disaster So Far
Device Tree The Disaster so Far Mark Rutland <[email protected]> ELC Europe 2013 Agenda Disaster is a strong word. Let's talk about: I What was wrong with board files I What device tree is (and what it isn't) I The ARM conversion so far I The problems we have, and how to fix them I What we need to do in future Where we came from Two big problems: I Hard-coded board description I Kernel must know every possible configuration I Minor revisions require a new kernel I Separate kernels per platform I Uncoordinated { \stepping on each others toes" I Difficult to test I Painful for distributions Planned solution: I Single image I Dynamic configuration I Move board description out of the kernel Device Tree { Overview I A data structure for describing hardware I Defined by OpenFirmware (IEEE1275-1994) I Extended by ePAPR & other supplements I Handled by OpenFirmware, U-Boot, ... I Used by *BSD, Linux, OS X, Solaris, Xen I Used on ARC, ARM(64) C6X, META, MicroBlaze, MIPS, OpenRISC, PowerPC, SPARC, x86, Xtensa I Generated by KVM tool, Xen, others Device Tree { Overview I Declarative hardware description I Describes hardware topology I Format not tied to OS internals I Hierarchical key value(-list) I Just a data structure I Conventions, not rigid rules I Bindings I Conventions for describing a particular devices I Typically matched by compatible string I Device classes share common bindings I No central authority I Bindings created by users I No coordination of implementors Device Tree { Bindings Vendor dev2000 bindings ======================= The Vendor dev2000 is a memory-mapped device that may or may not do something useful. -
Multi-Method Dispatch Using Single-Receiver Projections
Multi-Method Dispatch Using Single-Receiver Projections Wade Holst Duane Szafron Candy Pang Yuri Leontiev g fwade,duane,candy,yuri @cs.ualberta.ca Department of Computing Science University of Alberta Edmonton, Canada Abstract A new technique for multi-method dispatch, called Single-Receiver Projections and abbre- viated SRP, is presented. It operates by performing projections onto single-receiver dispatch tables, and thus benefits from existing research into single-receiver dispatch techniques. It pro- k vides method dispatch in O(k ), where is the arity of the method. Unlike existing multi-method dispatch techniques, it also maintains the set of all applicable methods. This extra information allows SRP to support languages like CLOS that use next-method. SRP is also highly incremen- tal in nature, so it is well-suited for languages that require separate compilation and languages that allow methods and classes to be added at run-time. SRP uses less data-structure memory than all existing multi-method techniques and has the second fastest dispatch time. Furthermore, if the other techniques are extended to support all applicable methods, SRP becomes the fastest dispatch techniques. RESEARCH PAPER Subject Areas: language design and implementation, programming environments Keywords: multi-method, dispatch, object-oriented, implementation, compiler Word Count: 8722 Contact Author: Duane Szafron Department of Computing Science University of Alberta Edmonton, Canada, T6G 2H1 Phone: (780) 492-5468 Fax: (780) 492-1071 Email: [email protected] 1 1 Introduction In object-oriented languages, the method to invoke is determined not only by the method (selector) name, but also by the dynamic types of its arguments. -
EXTENDING the LIFECYCLE of IOT DEVICES USING SELECTIVE DEACTIVATION a Dissertation Presented to the Academic Faculty by Michael
EXTENDING THE LIFECYCLE OF IOT DEVICES USING SELECTIVE DEACTIVATION A Dissertation Presented to The Academic Faculty By Michael Hesse In Partial Fulfillment of the Requirements for the Degree Master of Science in the School of Computer Science Georgia Institute of Technology August 2020 Copyright c Michael Hesse 2020 EXTENDING THE LIFECYCLE OF IOT DEVICES USING SELECTIVE DEACTIVATION Approved by: Professor Taesoo Kim, Advisor School of Computer Science Georgia Institute of Technology Professor Brendan Saltaformaggio School of Electrical and Computer Engineering Georgia Institute of Technology Professor Mustaque Ahmad School of Computer Science Georgia Institute of Technology Date Approved: April 29, 2020 ACKNOWLEDGEMENTS I would like to thank my advisor Taesoo Kim and the other members of the committee, Brendan Saltaformaggio and Mustaque Ahmad, for their time, patience and guidance, as this thesis would not have been possible without them. I would further like to thank Meng Xu and Fan San for their continued support and feedback during the course of my research. Ranjani and Sundar, thank you for emotional support and interest in my work. Finally, I would like to thank my parents and my sister for all the love and support they continue to provide throughout my entire life. iii TABLE OF CONTENTS Acknowledgments . iii List of Tables . viii List of Figures . ix Nomenclature . x Chapter 1: Introduction . 1 1.1 Problem Description . 2 1.2 Goal . 2 1.3 Assumptions & Threat Model . 4 1.4 Security Properties . 5 1.5 Challenges . 6 1.6 Thesis Overview . 6 Chapter 2: Background . 8 2.1 Platform Architecture . 8 2.2 Hardware Assisted Security Mechanisms . -
Create Platform Device for Node
devicetree: kernel internals and practical troubleshooting There have been many presentations on what a devicetree looks like and how to create a devicetree. This talk instead examines how the Linux kernel uses a devicetree. Topics include the kernel devicetree framework, device creation, resource allocation, driver binding, and connecting objects. Troubleshooting will consider initialization, allocation, and binding ordering; kernel configuration; and driver problems. Frank Rowand, Sony Mobile Communications August 22, 2014 140821_1927 CAUTION The material covered in this presentation is kernel version specific Most information describes 3.16 or earlier In cases where arch specific code is involved, there will be a bias to looking at arch/arm/ Chapter 1 Device tree what is device tree? “A device tree is a tree data structure with nodes that describe the devices in a system. Each node has property/value pairs that describe the characteristics of the device being represented. Each node has exactly one parent except for the root node, which has no parent.” (ePAPR v1.1) what is device tree? “A device tree is a tree data structure with nodes that describe the devices in a system. Each node has property/value pairs that describe the characteristics of the device being represented. Each node has exactly one parent except for the root node, which has no parent.” (ePAPR v1.1) A device tree describes hardware that can not be located by probing. DT data life cycle (source) .dts .dts - device tree source file / { /* incomplete .dts example */ model -
MIPS SDE 6.X Programmers' Guide
TECHNOLOGIES MIPS® SDE 6.x Programmers’ Guide Document Number: MD00428 Revision 1.17 April 4, 2007 MIPS Technologies, Inc 1225 Charleston Road Mountain View,CA94043-1353 Copyright © 1995-2007 MIPS Technologies, Inc. All rights reserved. Copyright © 1995-2007 MIPS Technologies, Inc. All rights reserved. Unpublished rights (if any) reserved under the copyright laws of the United States of America and other countries. This document contains information that is proprietary to MIPS Technologies, Inc. (‘‘MIPS Technologies’’). Any copying, reproducing, modifying or use of this information (in whole or in part) that is not expressly permitted in writing by MIPS Technologies or an authorized third party is strictly prohibited. At a minimum, this information is protected under unfair competition and copyright laws. Violations thereof may result in criminal penalties and fines. Anydocument provided in source format (i.e., in a modifiable form such as in FrameMaker or Microsoft Word format) is subject to use and distribution restrictions that are independent of and supplemental to anyand all confidentiality restrictions. UNDER NO CIRCUMSTANCES MAYADOCUMENT PROVIDED IN SOURCE FORMATBEDISTRIBUTED TOATHIRD PARTY IN SOURCE FORMATWITHOUT THE EXPRESS WRITTEN PERMISSION OF MIPS TECHNOLOGIES, INC. MIPS Technologies reserves the right to change the information contained in this document to improve function, design or otherwise. MIPS Technologies does not assume anyliability arising out of the application or use of this information, or of anyerror or omission in such information. Anywarranties, whether express, statutory,implied or otherwise, including but not limited to the implied warranties of merchantability or fitness for a particular purpose, are excluded. Except as expressly provided in anywritten license agreement from MIPS Technologies or an authorized third party,the furnishing of this document does not give recipient anylicense to anyintellectual property rights, including anypatent rights, that coverthe information in this document. -
A Tale of Reusability in Coreboot
A tale of reusability in coreboot Furquan Shaikh Table of contents - Introduction to Chrome OS and Chrome OS Platform Model - Objectives - SSDT generation - Baseboard and Variant Structure - Override devicetree - Current challenges Once upon a time…... What is Chrome OS ? Chrome Linux kernel depthcharge Libraries (e.g. blobs, third- vboot) coreboot party f/w, FSP AARCH64 ARM32 X86 ... What does Chrome OS platform look like ? Chrome Keyboard TCPC EC Linux kernel Touchscreen depthcharge Librarie Trackpad s (e.g. vboot) blobs, third- coreboot party f/w, FSP Camera PMIC TPM AARCH64 ARM32 X86 ... Audio Controllers Application Processor Peripherals Traditional Chrome OS Platform Model Google Reference Platform OEM #1 Lead Device OEM #2 OEM #3 OEM #4 OEM #5 Follower Device Follower Device Follower Device Follower Device Traditional Chrome OS Platform Model Google Reference glados Platform OEM #1 Lead chell Device OEM #2 OEM #3 OEM #4 OEM #5 Follower Follower Follower Follower caroline cave Device Device Device Device Traditional Chrome OS Platform Model Google Reference reef Platform OEM #1 Lead reef Device OEM #2 OEM #3 OEM #4 OEM #5 Follower Follower Follower Follower nasher pyro sand snappy Device Device Device Device Traditional ‸ Chrome OS Platform Model Google Reference reef Platform coral OEM #1 OEM #2 OEM #3 OEM #4 astronaut robo santa nasher ... Device Device Device Device Traditional ‸ Chrome OS Platform Model Google Reference octopus Platform yorp bip OEM #1 OEM #2 OEM #3 OEM #4 phaser meep fleex bobba ... Device Device Device Device