toolchain/share/doc/gdb/Memory-Map-Format.html

120 lines
5.5 KiB
HTML

<html lang="en">
<head>
<title>Memory Map Format - Debugging with GDB</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="Debugging with GDB">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Remote-Protocol.html#Remote-Protocol" title="Remote Protocol">
<link rel="prev" href="Library-List-Format-for-SVR4-Targets.html#Library-List-Format-for-SVR4-Targets" title="Library List Format for SVR4 Targets">
<link rel="next" href="Thread-List-Format.html#Thread-List-Format" title="Thread List Format">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1988-2019 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 the
Invariant Sections being ``Free Software'' and ``Free Software Needs
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
and with the Back-Cover Texts as in (a) below.
(a) The FSF's Back-Cover Text is: ``You are free to copy and modify
this GNU Manual. Buying copies from GNU Press supports the FSF in
developing GNU and promoting software freedom.''
-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="Memory-Map-Format"></a>
<p>
Next:&nbsp;<a rel="next" accesskey="n" href="Thread-List-Format.html#Thread-List-Format">Thread List Format</a>,
Previous:&nbsp;<a rel="previous" accesskey="p" href="Library-List-Format-for-SVR4-Targets.html#Library-List-Format-for-SVR4-Targets">Library List Format for SVR4 Targets</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Remote-Protocol.html#Remote-Protocol">Remote Protocol</a>
<hr>
</div>
<h3 class="section">E.16 Memory Map Format</h3>
<p><a name="index-memory-map-format-3633"></a>
To be able to write into flash memory, <span class="sc">gdb</span> needs to obtain a
memory map from the target. This section describes the format of the
memory map.
<p>The memory map is obtained using the &lsquo;<samp><span class="samp">qXfer:memory-map:read</span></samp>&rsquo;
(see <a href="qXfer-memory-map-read.html#qXfer-memory-map-read">qXfer memory map read</a>) packet and is an XML document that
lists memory regions.
<p><span class="sc">gdb</span> must be linked with the Expat library to support XML
memory maps. See <a href="Expat.html#Expat">Expat</a>.
<p>The top-level structure of the document is shown below:
<pre class="smallexample"> &lt;?xml version="1.0"?&gt;
&lt;!DOCTYPE memory-map
PUBLIC "+//IDN gnu.org//DTD GDB Memory Map V1.0//EN"
"http://sourceware.org/gdb/gdb-memory-map.dtd"&gt;
&lt;memory-map&gt;
region...
&lt;/memory-map&gt;
</pre>
<p>Each region can be either:
<ul>
<li>A region of RAM starting at <var>addr</var> and extending for <var>length</var>
bytes from there:
<pre class="smallexample"> &lt;memory type="ram" start="<var>addr</var>" length="<var>length</var>"/&gt;
</pre>
<li>A region of read-only memory:
<pre class="smallexample"> &lt;memory type="rom" start="<var>addr</var>" length="<var>length</var>"/&gt;
</pre>
<li>A region of flash memory, with erasure blocks <var>blocksize</var>
bytes in length:
<pre class="smallexample"> &lt;memory type="flash" start="<var>addr</var>" length="<var>length</var>"&gt;
&lt;property name="blocksize"&gt;<var>blocksize</var>&lt;/property&gt;
&lt;/memory&gt;
</pre>
</ul>
<p>Regions must not overlap. <span class="sc">gdb</span> assumes that areas of memory not covered
by the memory map are RAM, and uses the ordinary &lsquo;<samp><span class="samp">M</span></samp>&rsquo; and &lsquo;<samp><span class="samp">X</span></samp>&rsquo;
packets to write to addresses in such ranges.
<p>The formal DTD for memory map format is given below:
<pre class="smallexample"> &lt;!-- ................................................... --&gt;
&lt;!-- Memory Map XML DTD ................................ --&gt;
&lt;!-- File: memory-map.dtd .............................. --&gt;
&lt;!-- .................................... .............. --&gt;
&lt;!-- memory-map.dtd --&gt;
&lt;!-- memory-map: Root element with versioning --&gt;
&lt;!ELEMENT memory-map (memory)*&gt;
&lt;!ATTLIST memory-map version CDATA #FIXED "1.0.0"&gt;
&lt;!ELEMENT memory (property)*&gt;
&lt;!-- memory: Specifies a memory region,
and its type, or device. --&gt;
&lt;!ATTLIST memory type (ram|rom|flash) #REQUIRED
start CDATA #REQUIRED
length CDATA #REQUIRED&gt;
&lt;!-- property: Generic attribute tag --&gt;
&lt;!ELEMENT property (#PCDATA | property)*&gt;
&lt;!ATTLIST property name (blocksize) #REQUIRED&gt;
</pre>
</body></html>