<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Chapter 2. Compiling a kernel</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Using kgdb and the kgdb Internals" /><link rel="up" href="index.html" title="Using kgdb and the kgdb Internals" /><link rel="prev" href="ch01.html" title="Chapter 1. Introduction" /><link rel="next" href="ch03.html" title="Chapter 3. Enable kgdb for debugging" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 2. Compiling a kernel</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch01.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ch03.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 2. Compiling a kernel"><div class="titlepage"><div><div><h2 class="title"><a id="CompilingAKernel"></a>Chapter 2. Compiling a kernel</h2></div></div></div><p> To enable <span class="symbol">CONFIG_KGDB</span> you should first turn on "Prompt for development and/or incomplete code/drivers" (CONFIG_EXPERIMENTAL) in "General setup", then under the "Kernel debugging" select "KGDB: kernel debugging with remote gdb". </p><p> It is advised, but not required that you turn on the CONFIG_FRAME_POINTER kernel option. This option inserts code to into the compiled executable which saves the frame information in registers or on the stack at different points which will allow a debugger such as gdb to more accurately construct stack back traces while debugging the kernel. </p><p> If the architecture that you are using supports the kernel option CONFIG_DEBUG_RODATA, you should consider turning it off. This option will prevent the use of software breakpoints because it marks certain regions of the kernel's memory space as read-only. If kgdb supports it for the architecture you are using, you can use hardware breakpoints if you desire to run with the CONFIG_DEBUG_RODATA option turned on, else you need to turn off this option. </p><p> Next you should choose one of more I/O drivers to interconnect debugging host and debugged target. Early boot debugging requires a KGDB I/O driver that supports early debugging and the driver must be built into the kernel directly. Kgdb I/O driver configuration takes place via kernel or module parameters, see following chapter. </p><p> The kgdb test compile options are described in the kgdb test suite chapter. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch01.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="ch03.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 1. Introduction </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 3. Enable kgdb for debugging</td></tr></table></div></body></html>