DOCSLIB.ORG

The GNU Linker

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The GNU Linker The GNU linker ld (GNU Binutils) Version 2.36.50 Steve Chamberlain Ian Lance Taylor Red Hat Inc [email protected], [email protected] The GNU linker Edited by Jeffrey Osier ([email protected]) Copyright c 1991-2021 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled \GNU Free Documentation License". i Table of Contents 1 Overview :::::::::::::::::::::::::::::::::::::::: 1 2 Invocation ::::::::::::::::::::::::::::::::::::::: 3 2.1 Command-line Options ::::::::::::::::::::::::::::::::::::::::: 3 2.1.1 Options Specific to i386 PE Targets :::::::::::::::::::::: 39 2.1.2 Options specific to C6X uClinux targets :::::::::::::::::: 47 2.1.3 Options specific to Motorola 68HC11 and 68HC12 targets :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 47 2.1.4 Options specific to Motorola 68K target :::::::::::::::::: 47 2.2 Environment Variables :::::::::::::::::::::::::::::::::::::::: 47 3 Linker Scripts:::::::::::::::::::::::::::::::::: 49 3.1 Basic Linker Script Concepts :::::::::::::::::::::::::::::::::: 49 3.2 Linker Script Format :::::::::::::::::::::::::::::::::::::::::: 50 3.3 Simple Linker Script Example ::::::::::::::::::::::::::::::::: 50 3.4 Simple Linker Script Commands :::::::::::::::::::::::::::::: 51 3.4.1 Setting the Entry Point :::::::::::::::::::::::::::::::::: 51 3.4.2 Commands Dealing with Files :::::::::::::::::::::::::::: 51 3.4.3 Commands Dealing with Object File Formats::::::::::::: 53 3.4.4 Assign alias names to memory regions :::::::::::::::::::: 53 3.4.5 Other Linker Script Commands::::::::::::::::::::::::::: 56 3.5 Assigning Values to Symbols :::::::::::::::::::::::::::::::::: 58 3.5.1 Simple Assignments :::::::::::::::::::::::::::::::::::::: 58 3.5.2 HIDDEN::::::::::::::::::::::::::::::::::::::::::::::::: 59 3.5.3 PROVIDE ::::::::::::::::::::::::::::::::::::::::::::::: 59 3.5.4 PROVIDE HIDDEN ::::::::::::::::::::::::::::::::::::: 60 3.5.5 Source Code Reference ::::::::::::::::::::::::::::::::::: 60 3.6 SECTIONS Command :::::::::::::::::::::::::::::::::::::::: 61 3.6.1 Output Section Description::::::::::::::::::::::::::::::: 62 3.6.2 Output Section Name :::::::::::::::::::::::::::::::::::: 62 3.6.3 Output Section Address :::::::::::::::::::::::::::::::::: 62 3.6.4 Input Section Description :::::::::::::::::::::::::::::::: 63 3.6.4.1 Input Section Basics::::::::::::::::::::::::::::::::: 63 3.6.4.2 Input Section Wildcard Patterns::::::::::::::::::::: 65 3.6.4.3 Input Section for Common Symbols:::::::::::::::::: 67 3.6.4.4 Input Section and Garbage Collection:::::::::::::::: 67 3.6.4.5 Input Section Example :::::::::::::::::::::::::::::: 67 3.6.5 Output Section Data ::::::::::::::::::::::::::::::::::::: 68 3.6.6 Output Section Keywords :::::::::::::::::::::::::::::::: 69 3.6.7 Output Section Discarding ::::::::::::::::::::::::::::::: 70 3.6.8 Output Section Attributes:::::::::::::::::::::::::::::::: 70 3.6.8.1 Output Section Type :::::::::::::::::::::::::::::::: 71 ii The GNU linker 3.6.8.2 Output Section LMA :::::::::::::::::::::::::::::::: 71 3.6.8.3 Forced Output Alignment ::::::::::::::::::::::::::: 72 3.6.8.4 Forced Input Alignment ::::::::::::::::::::::::::::: 72 3.6.8.5 Output Section Constraint::::::::::::::::::::::::::: 73 3.6.8.6 Output Section Region :::::::::::::::::::::::::::::: 73 3.6.8.7 Output Section Phdr :::::::::::::::::::::::::::::::: 73 3.6.8.8 Output Section Fill:::::::::::::::::::::::::::::::::: 73 3.6.9 Overlay Description :::::::::::::::::::::::::::::::::::::: 73 3.7 MEMORY Command ::::::::::::::::::::::::::::::::::::::::: 75 3.8 PHDRS Command :::::::::::::::::::::::::::::::::::::::::::: 76 3.9 VERSION Command ::::::::::::::::::::::::::::::::::::::::: 79 3.10 Expressions in Linker Scripts ::::::::::::::::::::::::::::::::: 82 3.10.1 Constants ::::::::::::::::::::::::::::::::::::::::::::::: 82 3.10.2 Symbolic Constants ::::::::::::::::::::::::::::::::::::: 82 3.10.3 Symbol Names :::::::::::::::::::::::::::::::::::::::::: 82 3.10.4 Orphan Sections :::::::::::::::::::::::::::::::::::::::: 83 3.10.5 The Location Counter::::::::::::::::::::::::::::::::::: 83 3.10.6 Operators ::::::::::::::::::::::::::::::::::::::::::::::: 85 3.10.7 Evaluation :::::::::::::::::::::::::::::::::::::::::::::: 85 3.10.8 The Section of an Expression :::::::::::::::::::::::::::: 86 3.10.9 Builtin Functions ::::::::::::::::::::::::::::::::::::::: 87 3.11 Implicit Linker Scripts ::::::::::::::::::::::::::::::::::::::: 91 4 Linker Plugins ::::::::::::::::::::::::::::::::: 93 4.1 Static Library Dependencies Plugin ::::::::::::::::::::::::::: 93 5 Machine Dependent Features::::::::::::::::: 95 5.1 ld and the H8/300 :::::::::::::::::::::::::::::::::::::::::::: 95 5.2 ld and the Motorola 68HC11 and 68HC12 families::::::::::::: 95 5.2.1 Linker Relaxation :::::::::::::::::::::::::::::::::::::::: 95 5.2.2 Trampoline Generation ::::::::::::::::::::::::::::::::::: 96 5.3 ld and the ARM family ::::::::::::::::::::::::::::::::::::::: 96 5.4 ld and HPPA 32-bit ELF Support ::::::::::::::::::::::::::: 100 5.5 ld and the Motorola 68K family ::::::::::::::::::::::::::::: 100 5.6 ld and MMIX ::::::::::::::::::::::::::::::::::::::::::::::: 100 5.7 ld and MSP430 :::::::::::::::::::::::::::::::::::::::::::::: 101 5.8 ld and PowerPC 32-bit ELF Support :::::::::::::::::::::::: 101 5.9 ld and PowerPC64 64-bit ELF Support :::::::::::::::::::::: 102 5.10 ld and SPU ELF Support :::::::::::::::::::::::::::::::::: 105 5.11 ld's Support for Various TI COFF Versions ::::::::::::::::: 106 5.12 ld and WIN32 (cygwin/mingw) ::::::::::::::::::::::::::::: 107 5.13 ld and Xtensa Processors ::::::::::::::::::::::::::::::::::: 114 6 BFD ::::::::::::::::::::::::::::::::::::::::::: 117 6.1 How It Works: An Outline of BFD ::::::::::::::::::::::::::: 117 6.1.1 Information Loss :::::::::::::::::::::::::::::::::::::::: 117 6.1.2 The BFD canonical object-file format:::::::::::::::::::: 118 iii 7 Reporting Bugs :::::::::::::::::::::::::::::: 121 7.1 Have You Found a Bug? ::::::::::::::::::::::::::::::::::::: 121 7.2 How to Report Bugs ::::::::::::::::::::::::::::::::::::::::: 121 Appendix A MRI Compatible Script Files :: 125 Appendix B GNU Free Documentation License ::::::::::::::::::::::::::::::::::::::::::::::: 127 LD Index ::::::::::::::::::::::::::::::::::::::::: 135 Chapter 1: Overview 1 1 Overview ld combines a number of object and archive files, relocates their data and ties up symbol references. Usually the last step in compiling a program is to run ld. ld accepts Linker Command Language files written in a superset of AT&T's Link Editor Command Language syntax, to provide explicit and total control over the linking process. This version of ld uses the general purpose BFD libraries to operate on object files. This allows ld to read, combine, and write object files in many different formats|for example, COFF or a.out. Different formats may be linked together to produce any available kindof object file. See Chapter 6 [BFD], page 117, for more information. Aside from its flexibility, the gnu linker is more helpful than other linkers in providing diagnostic information. Many linkers abandon execution immediately upon encountering an error; whenever possible, ld continues executing, allowing you to identify other errors (or, in some cases, to get an output file in spite of the error). Chapter 2: Invocation 3 2 Invocation The gnu linker ld is meant to cover a broad range of situations, and to be as compatible as possible with other linkers. As a result, you have many choices to control its behavior. 2.1 Command-line Options The linker supports a plethora of command-line options, but in actual practice few of them are used in any particular context. For instance, a frequent use of ld is to link standard Unix object files on a standard, supported Unix system. On such a system, to link afile hello.o: ld -o output /lib/crt0.o hello.o -lc This tells ld to produce a file called output as the result of linking the file /lib/crt0.o with hello.o and the library libc.a, which will come from the standard search directories. (See the discussion of the `-l' option below.) Some of the command-line options to ld may be specified at any point in the command line. However, options which refer to files, such as-l ` ' or `-T', cause the file to be read at the point at which the option appears in the command line, relative to the object files and other file options. Repeating non-file options with a different argument will either haveno further effect, or override prior occurrences (those further to the left on the command line) of that option. Options which may be meaningfully specified more than once are noted in the descriptions below. Non-option arguments are object files or archives which are to be linked together. They may follow, precede, or be mixed in with command-line options, except that an object file argument may not be placed between an option and its argument. Usually the linker is invoked with at least one object file, but you can specify other forms of binary input files using-l ` ', `-R', and the script command language. If no binary input files at all are specified, the linker does not produce any output, and issues themessage`No input files'. If the linker cannot recognize the format of an object file, it will assume that it is a linker
Load more

Recommended publications
  • Introduction to Computer Systems 15-213/18-243, Spring 2009 1St
    M4-L3: Executables CSE351, Winter 2021 Executables CSE 351 Winter 2021 Instructor: Teaching Assistants: Mark Wyse Kyrie Dowling Catherine Guevara Ian Hsiao Jim Limprasert Armin Magness Allie Pfleger Cosmo Wang Ronald Widjaja http://xkcd.com/1790/ M4-L3: Executables CSE351, Winter 2021 Administrivia ❖ Lab 2 due Monday (2/8) ❖ hw12 due Friday ❖ hw13 due next Wednesday (2/10) ▪ Based on the next two lectures, longer than normal ❖ Remember: HW and readings due before lecture, at 11am PST on due date 2 M4-L3: Executables CSE351, Winter 2021 Roadmap C: Java: Memory & data car *c = malloc(sizeof(car)); Car c = new Car(); Integers & floats c->miles = 100; c.setMiles(100); x86 assembly c->gals = 17; c.setGals(17); Procedures & stacks float mpg = get_mpg(c); float mpg = Executables free(c); c.getMPG(); Arrays & structs Memory & caches Assembly get_mpg: Processes pushq %rbp language: movq %rsp, %rbp Virtual memory ... Memory allocation popq %rbp Java vs. C ret OS: Machine 0111010000011000 100011010000010000000010 code: 1000100111000010 110000011111101000011111 Computer system: 3 M4-L3: Executables CSE351, Winter 2021 Reading Review ❖ Terminology: ▪ CALL: compiler, assembler, linker, loader ▪ Object file: symbol table, relocation table ▪ Disassembly ▪ Multidimensional arrays, row-major ordering ▪ Multilevel arrays ❖ Questions from the Reading? ▪ also post to Ed post! 4 M4-L3: Executables CSE351, Winter 2021 Building an Executable from a C File ❖ Code in files p1.c p2.c ❖ Compile with command: gcc -Og p1.c p2.c -o p ▪ Put resulting machine code in
    [Show full text]
  • CERES Software Bulletin 95-12
    CERES Software Bulletin 95-12 Fortran 90 Linking Experiences, September 5, 1995 1.0 Purpose: To disseminate experience gained in the process of linking Fortran 90 software with library routines compiled under Fortran 77 compiler. 2.0 Originator: Lyle Ziegelmiller ([email protected]) 3.0 Description: One of the summer students, Julia Barsie, was working with a plot program which was written in f77. This program called routines from a graphics package known as NCAR, which is also written in f77. Everything was fine. The plot program was converted to f90, and a new version of the NCAR graphical package was released, which was written in f77. A problem arose when trying to link the new f90 version of the plot program with the new f77 release of NCAR; many undefined references were reported by the linker. This bulletin is intended to convey what was learned in the effort to accomplish this linking. The first step I took was to issue the "-dryrun" directive to the f77 compiler when using it to compile the original f77 plot program and the original NCAR graphics library. "- dryrun" causes the linker to produce an output detailing all the various libraries that it links with. Note that these libaries are in addition to the libaries you would select on the command line. For example, you might compile a program with erbelib, but the linker would have to link with librarie(s) that contain the definitions of sine or cosine. Anyway, it was my hypothesis that if everything compiled and linked with f77, then all the libraries must be contained in the output from the f77's "-dryrun" command.
    [Show full text]
  • Linking + Libraries
    LinkingLinking ● Last stage in building a program PRE- COMPILATION ASSEMBLY LINKING PROCESSING ● Combining separate code into one executable ● Linking done by the Linker ● ld in Unix ● a.k.a. “link-editor” or “loader” ● Often transparent (gcc can do it all for you) 1 LinkingLinking involves...involves... ● Combining several object modules (the .o files corresponding to .c files) into one file ● Resolving external references to variables and functions ● Producing an executable file (if no errors) file1.c file1.o file2.c gcc file2.o Linker Executable fileN.c fileN.o Header files External references 2 LinkingLinking withwith ExternalExternal ReferencesReferences file1.c file2.c int count; #include <stdio.h> void display(void); Compiler extern int count; int main(void) void display(void) { file1.o file2.o { count = 10; with placeholders printf(“%d”,count); display(); } return 0; Linker } ● file1.o has placeholder for display() ● file2.o has placeholder for count ● object modules are relocatable ● addresses are relative offsets from top of file 3 LibrariesLibraries ● Definition: ● a file containing functions that can be referenced externally by a C program ● Purpose: ● easy access to functions used repeatedly ● promote code modularity and re-use ● reduce source and executable file size 4 LibrariesLibraries ● Static (Archive) ● libname.a on Unix; name.lib on DOS/Windows ● Only modules with referenced code linked when compiling ● unlike .o files ● Linker copies function from library into executable file ● Update to library requires recompiling program 5 LibrariesLibraries ● Dynamic (Shared Object or Dynamic Link Library) ● libname.so on Unix; name.dll on DOS/Windows ● Referenced code not copied into executable ● Loaded in memory at run time ● Smaller executable size ● Can update library without recompiling program ● Drawback: slightly slower program startup 6 LibrariesLibraries ● Linking a static library libpepsi.a /* crave source file */ … gcc ..
    [Show full text]
  • Using the DLFM Package on the Cray XE6 System
    Using the DLFM Package on the Cray XE6 System Mike Davis, Cray Inc. Version 1.4 - October 2013 1.0: Introduction The DLFM package is a set of libraries and tools that can be applied to a dynamically-linked application, or an application that uses Python, to provide improved performance during the loading of dynamic libraries and importing of Python modules when running the application at large scale. Included in the DLFM package are: a set of wrapper functions that interface with the dynamic linker (ld.so) to cache the application's dynamic library load operations; and a custom libpython.so, with a set of optimized components, that caches the application's Python import operations. 2.0: Dynamic Linking and Python Importing Without DLFM When a dynamically-linked application is executed, the set of dependent libraries is loaded in sequence by ld.so prior to the transfer of control to the application's main function. This set of dependent libraries ordinarily numbers a dozen or so, but can number many more, depending on the needs of the application; their names and paths are given by the ldd(1) command. As ld.so processes each dependent library, it executes a series of system calls to find the library and make the library's contents available to the application. These include: fd = open (/path/to/dependent/library, O_RDONLY); read (fd, elfhdr, 832); // to get the library ELF header fstat (fd, &stbuf); // to get library attributes, such as size mmap (buf, length, prot, MAP_PRIVATE, fd, offset); // read text segment mmap (buf, length, prot, MAP_PRIVATE, fd, offset); // read data segment close (fd); The number of open() calls can be many times larger than the number of dependent libraries, because ld.so must search for each dependent library in multiple locations, as described on the ld.so(1) man page.
    [Show full text]
  • Introduction to GNU Octave
    Introduction to GNU Octave Hubert Selhofer, revised by Marcel Oliver updated to current Octave version by Thomas L. Scofield 2008/08/16 line 1 1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 8 6 4 2 -8 -6 0 -4 -2 -2 0 -4 2 4 -6 6 8 -8 Contents 1 Basics 2 1.1 What is Octave? ........................... 2 1.2 Help! . 2 1.3 Input conventions . 3 1.4 Variables and standard operations . 3 2 Vector and matrix operations 4 2.1 Vectors . 4 2.2 Matrices . 4 1 2.3 Basic matrix arithmetic . 5 2.4 Element-wise operations . 5 2.5 Indexing and slicing . 6 2.6 Solving linear systems of equations . 7 2.7 Inverses, decompositions, eigenvalues . 7 2.8 Testing for zero elements . 8 3 Control structures 8 3.1 Functions . 8 3.2 Global variables . 9 3.3 Loops . 9 3.4 Branching . 9 3.5 Functions of functions . 10 3.6 Efficiency considerations . 10 3.7 Input and output . 11 4 Graphics 11 4.1 2D graphics . 11 4.2 3D graphics: . 12 4.3 Commands for 2D and 3D graphics . 13 5 Exercises 13 5.1 Linear algebra . 13 5.2 Timing . 14 5.3 Stability functions of BDF-integrators . 14 5.4 3D plot . 15 5.5 Hilbert matrix . 15 5.6 Least square fit of a straight line . 16 5.7 Trapezoidal rule . 16 1 Basics 1.1 What is Octave? Octave is an interactive programming language specifically suited for vectoriz- able numerical calculations.
    [Show full text]
  • Lecture 1: Introduction to UNIX
    The Operating System Course Overview Getting Started Lecture 1: Introduction to UNIX CS2042 - UNIX Tools September 29, 2008 Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages Lecture Outline 1 The Operating System Description and History UNIX Flavors Advantages and Disadvantages 2 Course Overview Class Specifics 3 Getting Started Login Information Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages What is UNIX? One of the first widely-used operating systems Basis for many modern OSes Helped set the standard for multi-tasking, multi-user systems Strictly a teaching tool (in its original form) Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages A Brief History of UNIX Origins The first version of UNIX was created in 1969 by a group of guys working for AT&T's Bell Labs. It was one of the first big projects written in the emerging C language. It gained popularity throughout the '70s and '80s, although non-AT&T versions eventually took the lion's share of the market. Predates Microsoft's DOS by 12 years! Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages Lecture Outline 1 The Operating System Description and History UNIX Flavors Advantages and Disadvantages 2 Course Overview Class Specifics 3
    [Show full text]
  • Environment Variable and Set-UID Program Lab 1
    SEED Labs – Environment Variable and Set-UID Program Lab 1 Environment Variable and Set-UID Program Lab Copyright © 2006 - 2016 Wenliang Du, All rights reserved. Free to use for non-commercial educational purposes. Commercial uses of the materials are prohibited. The SEED project was funded by multiple grants from the US National Science Foundation. 1 Overview The learning objective of this lab is for students to understand how environment variables affect program and system behaviors. Environment variables are a set of dynamic named values that can affect the way running processes will behave on a computer. They are used by most operating systems, since they were introduced to Unix in 1979. Although environment variables affect program behaviors, how they achieve that is not well understood by many programmers. As a result, if a program uses environment variables, but the programmer does not know that they are used, the program may have vulnerabilities. In this lab, students will understand how environment variables work, how they are propagated from parent process to child, and how they affect system/program behaviors. We are particularly interested in how environment variables affect the behavior of Set-UID programs, which are usually privileged programs. This lab covers the following topics: • Environment variables • Set-UID programs • Securely invoke external programs • Capability leaking • Dynamic loader/linker Readings and videos. Detailed coverage of the Set-UID mechanism, environment variables, and their related security problems can be found in the following: • Chapters 1 and 2 of the SEED Book, Computer & Internet Security: A Hands-on Approach, 2nd Edition, by Wenliang Du.
    [Show full text]
  • Toolchains Instructor: Prabal Dutta Date: October 2, 2012
    EECS 373: Design of Microprocessor-Based Systems Fall 2012 Lecture 3: Toolchains Instructor: Prabal Dutta Date: October 2, 2012 Note: Unless otherwise specified, these notes assume: (i) an ARM Cortex-M3 processor operating in little endian mode; (ii) the ARM EABI application binary interface; and (iii) the GNU GCC toolchain. Toolchains A complete software toolchain includes programs to convert source code into binary machine code, link together separately assembled/compiled code modules, disassemble the binaries, and convert their formats. Binary program file (.bin) Assembly Object Executable files (.s) files (.o) image file objcopy ld (linker) as objdump (assembler) Memory layout Disassembled Linker code (.lst) script (.ld) Figure 0.1: Assembler Toolchain. A typical GNU (GNU's Not Unix) assembler toolchain includes several programs that interact as shown in Figure 0.1 and perform the following functions: • as is the assembler and it converts human-readable assembly language programs into binary machine language code. It typically takes as input .s assembly files and outputs .o object files. • ld is the linker and it is used to combine multiple object files by resolving their external symbol references and relocating their data sections, and outputting a single executable file. It typically takes as input .o object files and .ld linker scripts and outputs .out executable files. • objcopy is a translation utility that copies and converts the contents of an object file from one format (e.g. .out) another (e.g. .bin). • objdump is a disassembler but it can also display various other information about object files. It is often used to disassemble binary files (e.g.
    [Show full text]
  • Université De Montréal Context-Aware
    UNIVERSITE´ DE MONTREAL´ CONTEXT-AWARE SOURCE CODE IDENTIFIER SPLITTING AND EXPANSION FOR SOFTWARE MAINTENANCE LATIFA GUERROUJ DEPARTEMENT´ DE GENIE´ INFORMATIQUE ET GENIE´ LOGICIEL ECOLE´ POLYTECHNIQUE DE MONTREAL´ THESE` PRESENT´ EE´ EN VUE DE L'OBTENTION DU DIPLOME^ DE PHILOSOPHIÆ DOCTOR (GENIE´ INFORMATIQUE) JUILLET 2013 ⃝c Latifa Guerrouj, 2013. UNIVERSITE´ DE MONTREAL´ ECOLE´ POLYTECHNIQUE DE MONTREAL´ Cette th`ese intitul´ee: CONTEXT-AWARE SOURCE CODE IDENTIFIER SPLITTING AND EXPANSION FOR SOFTWARE MAINTENANCE pr´esent´eepar: GUERROUJ Latifa en vue de l'obtention du dipl^ome de: Philosophiæ Doctor a ´et´ed^ument accept´eepar le jury d'examen constitu´ede: Mme BOUCHENEB Hanifa, Doctorat, pr´esidente M. ANTONIOL Giuliano, Ph.D., membre et directeur de recherche M. GUEH´ ENEUC´ Yann-Ga¨el, Ph.D., membre et codirecteur de recherche M. DESMARAIS Michel, Ph.D., membre Mme LAWRIE Dawn, Ph.D., membre iii This dissertation is dedicated to my parents. For their endless love, support and encouragement. iv ACKNOWLEDGMENTS I am very grateful to both Giulio and Yann for their support, encouragement, and intel- lectual input. I worked with you for four years or even less, but what I learned from you will last forever. Giulio, your passion about research was a source of inspiration and motivation for me. Also, your mentoring and support have been instrumental in achieving my goals. Yann, your enthusiasm and guidance have always been a strength for me to keep moving forward. Research would not be as much fun without students and researchers to collaborate with. It has been a real pleasure and great privilege working with Massimiliano Di Penta (University of Sannio), Denys Poshyvanyk (College of William and Mary), and their teams.
    [Show full text]
  • Debian GNU/Linux Installation Guide Debian GNU/Linux Installation Guide Copyright © 2004 – 2015 the Debian Installer Team
    Debian GNU/Linux Installation Guide Debian GNU/Linux Installation Guide Copyright © 2004 – 2015 the Debian Installer team This document contains installation instructions for the Debian GNU/Linux 8 system (codename “jessie”), for the 32-bit soft-float ARM (“armel”) architecture. It also contains pointers to more information and information on how to make the most of your new Debian system. Note: Although this installation guide for armel is mostly up-to-date, we plan to make some changes and reorganize parts of the manual after the official release of jessie. A newer version of this manual may be found on the Internet at the debian-installer home page (http://www.debian.org/devel/debian-installer/). You may also be able to find additional translations there. This manual is free software; you may redistribute it and/or modify it under the terms of the GNU General Public License. Please refer to the license in Appendix F. Table of Contents Installing Debian GNU/Linux 8 For armel......................................................................................ix 1. Welcome to Debian .........................................................................................................................1 1.1. What is Debian? ...................................................................................................................1 1.2. What is GNU/Linux? ...........................................................................................................2 1.3. What is Debian GNU/Linux?...............................................................................................3
    [Show full text]
  • Xv6 Booting: Transitioning from 16 to 32 Bit Mode
    238P Operating Systems, Fall 2018 xv6 Boot Recap: Transitioning from 16 bit mode to 32 bit mode 3 November 2018 Aftab Hussain University of California, Irvine BIOS xv6 Boot loader what it does Sets up the hardware. Transfers control to the Boot Loader. BIOS xv6 Boot loader what it does Sets up the hardware. Transfers control to the Boot Loader. how it transfers control to the Boot Loader Boot loader is loaded from the 1st 512-byte sector of the boot disk. This 512-byte sector is known as the boot sector. Boot loader is loaded at 0x7c00. Sets processor’s ip register to 0x7c00. BIOS xv6 Boot loader 2 source source files bootasm.S - 16 and 32 bit assembly code. bootmain.c - C code. BIOS xv6 Boot loader 2 source source files bootasm.S - 16 and 32 bit assembly code. bootmain.c - C code. executing bootasm.S 1. Disable interrupts using cli instruction. (Code). > Done in case BIOS has initialized any of its interrupt handlers while setting up the hardware. Also, BIOS is not running anymore, so better to disable them. > Clear segment registers. Use xor for %ax, and copy it to the rest (Code). 2. Switch from real mode to protected mode. (References: a, b). > Note the difference between processor modes and kernel privilege modes > We do the above switch to increase the size of the memory we can address. BIOS xv6 Boot loader 2 source source file executing bootasm.S m. Let’s 2. Switch from real mode to protected mode. expand on this a little bit Addressing in Real Mode In real mode, the processor sends 20-bit addresses to the memory.
    [Show full text]
  • Chapter 6: the Linker
    6. The Linker 6-1 Chapter 6: The Linker References: • Brian W. Kernighan / Dennis M. Ritchie: The C Programming Language, 2nd Ed. Prentice-Hall, 1988. • Samuel P. Harbison / Guy L. Steele Jr.: C — A Reference Manual, 4th Ed. Prentice-Hall, 1995. • Online Documentation of Microsoft Visual C++ 6.0 (Standard Edition): MSDN Library: Visual Studio 6.0 release. • Horst Wettstein: Assemblierer und Binder (in German). Carl Hanser Verlag, 1979. • Peter Rechenberg, Gustav Pomberger (Eds.): Informatik-Handbuch (in German). Carl Hanser Verlag, 1997. Kapitel 12: Systemsoftware (H. M¨ossenb¨ock). Stefan Brass: Computer Science III Universit¨atGiessen, 2001 6. The Linker 6-2 Overview ' $ 1. Introduction (Overview) & % 2. Object Files, Libraries, and the Linker 3. Make 4. Dynamic Linking Stefan Brass: Computer Science III Universit¨atGiessen, 2001 6. The Linker 6-3 Introduction (1) • Often, a program consists of several modules which are separately compiled. Reasons are: The program is large. Even with fast computers, editing and compiling a single file with a million lines leads to unnecessary delays. The program is developed by several people. Different programmers cannot easily edit the same file at the same time. (There is software for collaborative work that permits that, but it is still a research topic.) A large program is easier to understand if it is divided into natural units. E.g. each module defines one data type with its operations. Stefan Brass: Computer Science III Universit¨atGiessen, 2001 6. The Linker 6-4 Introduction (2) • Reasons for splitting a program into several source files (continued): The same module might be used in different pro- grams (e.g.
    [Show full text]