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diff --git a/share/doc/gdb/Memory-Region-Attributes.html b/share/doc/gdb/Memory-Region-Attributes.html new file mode 100644 index 0000000..3da8037 --- /dev/null +++ b/share/doc/gdb/Memory-Region-Attributes.html @@ -0,0 +1,252 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 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." --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Debugging with GDB: Memory Region Attributes</title> + +<meta name="description" content="Debugging with GDB: Memory Region Attributes"> +<meta name="keywords" content="Debugging with GDB: Memory Region Attributes"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Data.html#Data" rel="up" title="Data"> +<link href="Dump_002fRestore-Files.html#Dump_002fRestore-Files" rel="next" title="Dump/Restore Files"> +<link href="OS-Information.html#OS-Information" rel="previous" title="OS Information"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Memory-Region-Attributes"></a> +<div class="header"> +<p> +Next: <a href="Dump_002fRestore-Files.html#Dump_002fRestore-Files" accesskey="n" rel="next">Dump/Restore Files</a>, Previous: <a href="OS-Information.html#OS-Information" accesskey="p" rel="previous">OS Information</a>, Up: <a href="Data.html#Data" accesskey="u" rel="up">Data</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Memory-Region-Attributes-1"></a> +<h3 class="section">10.18 Memory Region Attributes</h3> +<a name="index-memory-region-attributes"></a> + +<p><em>Memory region attributes</em> allow you to describe special handling +required by regions of your target’s memory. <small>GDB</small> uses +attributes to determine whether to allow certain types of memory +accesses; whether to use specific width accesses; and whether to cache +target memory. By default the description of memory regions is +fetched from the target (if the current target supports this), but the +user can override the fetched regions. +</p> +<p>Defined memory regions can be individually enabled and disabled. When a +memory region is disabled, <small>GDB</small> uses the default attributes when +accessing memory in that region. Similarly, if no memory regions have +been defined, <small>GDB</small> uses the default attributes when accessing +all memory. +</p> +<p>When a memory region is defined, it is given a number to identify it; +to enable, disable, or remove a memory region, you specify that number. +</p> +<dl compact="compact"> +<dd><a name="index-mem"></a> +</dd> +<dt><code>mem <var>lower</var> <var>upper</var> <var>attributes</var>…</code></dt> +<dd><p>Define a memory region bounded by <var>lower</var> and <var>upper</var> with +attributes <var>attributes</var>…, and add it to the list of regions +monitored by <small>GDB</small>. Note that <var>upper</var> == 0 is a special +case: it is treated as the target’s maximum memory address. +(0xffff on 16 bit targets, 0xffffffff on 32 bit targets, etc.) +</p> +</dd> +<dt><code>mem auto</code></dt> +<dd><p>Discard any user changes to the memory regions and use target-supplied +regions, if available, or no regions if the target does not support. +</p> +<a name="index-delete-mem"></a> +</dd> +<dt><code>delete mem <var>nums</var>…</code></dt> +<dd><p>Remove memory regions <var>nums</var>… from the list of regions +monitored by <small>GDB</small>. +</p> +<a name="index-disable-mem"></a> +</dd> +<dt><code>disable mem <var>nums</var>…</code></dt> +<dd><p>Disable monitoring of memory regions <var>nums</var>…. +A disabled memory region is not forgotten. +It may be enabled again later. +</p> +<a name="index-enable-mem"></a> +</dd> +<dt><code>enable mem <var>nums</var>…</code></dt> +<dd><p>Enable monitoring of memory regions <var>nums</var>…. +</p> +<a name="index-info-mem"></a> +</dd> +<dt><code>info mem</code></dt> +<dd><p>Print a table of all defined memory regions, with the following columns +for each region: +</p> +<dl compact="compact"> +<dt><em>Memory Region Number</em></dt> +<dt><em>Enabled or Disabled.</em></dt> +<dd><p>Enabled memory regions are marked with ‘<samp>y</samp>’. +Disabled memory regions are marked with ‘<samp>n</samp>’. +</p> +</dd> +<dt><em>Lo Address</em></dt> +<dd><p>The address defining the inclusive lower bound of the memory region. +</p> +</dd> +<dt><em>Hi Address</em></dt> +<dd><p>The address defining the exclusive upper bound of the memory region. +</p> +</dd> +<dt><em>Attributes</em></dt> +<dd><p>The list of attributes set for this memory region. +</p></dd> +</dl> +</dd> +</dl> + + +<a name="Attributes"></a> +<h4 class="subsection">10.18.1 Attributes</h4> + +<a name="Memory-Access-Mode"></a> +<h4 class="subsubsection">10.18.1.1 Memory Access Mode</h4> +<p>The access mode attributes set whether <small>GDB</small> may make read or +write accesses to a memory region. +</p> +<p>While these attributes prevent <small>GDB</small> from performing invalid +memory accesses, they do nothing to prevent the target system, I/O DMA, +etc. from accessing memory. +</p> +<dl compact="compact"> +<dt><code>ro</code></dt> +<dd><p>Memory is read only. +</p></dd> +<dt><code>wo</code></dt> +<dd><p>Memory is write only. +</p></dd> +<dt><code>rw</code></dt> +<dd><p>Memory is read/write. This is the default. +</p></dd> +</dl> + +<a name="Memory-Access-Size"></a> +<h4 class="subsubsection">10.18.1.2 Memory Access Size</h4> +<p>The access size attribute tells <small>GDB</small> to use specific sized +accesses in the memory region. Often memory mapped device registers +require specific sized accesses. If no access size attribute is +specified, <small>GDB</small> may use accesses of any size. +</p> +<dl compact="compact"> +<dt><code>8</code></dt> +<dd><p>Use 8 bit memory accesses. +</p></dd> +<dt><code>16</code></dt> +<dd><p>Use 16 bit memory accesses. +</p></dd> +<dt><code>32</code></dt> +<dd><p>Use 32 bit memory accesses. +</p></dd> +<dt><code>64</code></dt> +<dd><p>Use 64 bit memory accesses. +</p></dd> +</dl> + + +<a name="Data-Cache"></a> +<h4 class="subsubsection">10.18.1.3 Data Cache</h4> +<p>The data cache attributes set whether <small>GDB</small> will cache target +memory. While this generally improves performance by reducing debug +protocol overhead, it can lead to incorrect results because <small>GDB</small> +does not know about volatile variables or memory mapped device +registers. +</p> +<dl compact="compact"> +<dt><code>cache</code></dt> +<dd><p>Enable <small>GDB</small> to cache target memory. +</p></dd> +<dt><code>nocache</code></dt> +<dd><p>Disable <small>GDB</small> from caching target memory. This is the default. +</p></dd> +</dl> + +<a name="Memory-Access-Checking"></a> +<h4 class="subsection">10.18.2 Memory Access Checking</h4> +<p><small>GDB</small> can be instructed to refuse accesses to memory that is +not explicitly described. This can be useful if accessing such +regions has undesired effects for a specific target, or to provide +better error checking. The following commands control this behaviour. +</p> +<dl compact="compact"> +<dd><a name="index-set-mem-inaccessible_002dby_002ddefault"></a> +</dd> +<dt><code>set mem inaccessible-by-default [on|off]</code></dt> +<dd><p>If <code>on</code> is specified, make <small>GDB</small> treat memory not +explicitly described by the memory ranges as non-existent and refuse accesses +to such memory. The checks are only performed if there’s at least one +memory range defined. If <code>off</code> is specified, make <small>GDB</small> +treat the memory not explicitly described by the memory ranges as RAM. +The default value is <code>on</code>. +<a name="index-show-mem-inaccessible_002dby_002ddefault"></a> +</p></dd> +<dt><code>show mem inaccessible-by-default</code></dt> +<dd><p>Show the current handling of accesses to unknown memory. +</p></dd> +</dl> + + + +<hr> +<div class="header"> +<p> +Next: <a href="Dump_002fRestore-Files.html#Dump_002fRestore-Files" accesskey="n" rel="next">Dump/Restore Files</a>, Previous: <a href="OS-Information.html#OS-Information" accesskey="p" rel="previous">OS Information</a>, Up: <a href="Data.html#Data" accesskey="u" rel="up">Data</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |