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diff --git a/share/doc/gdb/AArch64.html b/share/doc/gdb/AArch64.html new file mode 100644 index 0000000..21ff296 --- /dev/null +++ b/share/doc/gdb/AArch64.html @@ -0,0 +1,182 @@ +<!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: AArch64</title> + +<meta name="description" content="Debugging with GDB: AArch64"> +<meta name="keywords" content="Debugging with GDB: AArch64"> +<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="Architectures.html#Architectures" rel="up" title="Architectures"> +<link href="i386.html#i386" rel="next" title="i386"> +<link href="Architectures.html#Architectures" rel="previous" title="Architectures"> +<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="AArch64"></a> +<div class="header"> +<p> +Next: <a href="i386.html#i386" accesskey="n" rel="next">i386</a>, Up: <a href="Architectures.html#Architectures" accesskey="u" rel="up">Architectures</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="AArch64-1"></a> +<h4 class="subsection">21.4.1 AArch64</h4> +<a name="index-AArch64-support"></a> + +<p>When <small>GDB</small> is debugging the AArch64 architecture, it provides the +following special commands: +</p> +<dl compact="compact"> +<dt><code>set debug aarch64</code></dt> +<dd><a name="index-set-debug-aarch64"></a> +<p>This command determines whether AArch64 architecture-specific debugging +messages are to be displayed. +</p> +</dd> +<dt><code>show debug aarch64</code></dt> +<dd><p>Show whether AArch64 debugging messages are displayed. +</p> +</dd> +</dl> + +<a name="AArch64-SVE_002e"></a> +<h4 class="subsubsection">21.4.1.1 AArch64 SVE.</h4> +<a name="index-AArch64-SVE_002e"></a> + +<p>When <small>GDB</small> is debugging the AArch64 architecture, if the Scalable Vector +Extension (SVE) is present, then <small>GDB</small> will provide the vector registers +<code>$z0</code> through <code>$z31</code>, vector predicate registers <code>$p0</code> through +<code>$p15</code>, and the <code>$ffr</code> register. In addition, the pseudo register +<code>$vg</code> will be provided. This is the vector granule for the current thread +and represents the number of 64-bit chunks in an SVE <code>z</code> register. +</p> +<p>If the vector length changes, then the <code>$vg</code> register will be updated, +but the lengths of the <code>z</code> and <code>p</code> registers will not change. This +is a known limitation of <small>GDB</small> and does not affect the execution of the +target process. +</p> +<a name="AArch64-Pointer-Authentication_002e"></a> +<h4 class="subsubsection">21.4.1.2 AArch64 Pointer Authentication.</h4> +<a name="index-AArch64-Pointer-Authentication_002e"></a> +<a name="AArch64-PAC"></a> +<p>When <small>GDB</small> is debugging the AArch64 architecture, and the program is +using the v8.3-A feature Pointer Authentication (PAC), then whenever the link +register <code>$lr</code> is pointing to an PAC function its value will be masked. +When GDB prints a backtrace, any addresses that required unmasking will be +postfixed with the marker [PAC]. When using the MI, this is printed as part +of the <code>addr_flags</code> field. +</p> +<a name="AArch64-Memory-Tagging-Extension_002e"></a> +<h4 class="subsubsection">21.4.1.3 AArch64 Memory Tagging Extension.</h4> +<a name="index-AArch64-Memory-Tagging-Extension_002e"></a> + +<p>When <small>GDB</small> is debugging the AArch64 architecture, the program is +using the v8.5-A feature Memory Tagging Extension (MTE) and there is support +in the kernel for MTE, <small>GDB</small> will make memory tagging functionality +available for inspection and editing of logical and allocation tags. +See <a href="Memory-Tagging.html#Memory-Tagging">Memory Tagging</a>. +</p> +<p>To aid debugging, <small>GDB</small> will output additional information when SIGSEGV +signals are generated as a result of memory tag failures. +</p> +<p>If the tag violation is synchronous, the following will be shown: +</p> +<div class="smallexample"> +<pre class="smallexample">Program received signal SIGSEGV, Segmentation fault +Memory tag violation while accessing address 0x0500fffff7ff8000 +Allocation tag 0x1 +Logical tag 0x5. +</pre></div> + +<p>If the tag violation is asynchronous, the fault address is not available. +In this case <small>GDB</small> will show the following: +</p> +<div class="smallexample"> +<pre class="smallexample">Program received signal SIGSEGV, Segmentation fault +Memory tag violation +Fault address unavailable. +</pre></div> + +<p>A special register, <code>tag_ctl</code>, is made available through the +<code>org.gnu.gdb.aarch64.mte</code> feature. This register exposes some +options that can be controlled at runtime and emulates the <code>prctl</code> +option <code>PR_SET_TAGGED_ADDR_CTRL</code>. For further information, see the +documentation in the Linux kernel. +</p> +<p><small>GDB</small> supports dumping memory tag data to core files through the +<code>gcore</code> command and reading memory tag data from core files generated +by the <code>gcore</code> command or the Linux kernel. +</p> +<p>When a process uses memory-mapped pages protected by memory tags (for +example, AArch64 MTE), this additional information will be recorded in +the core file in the event of a crash or if <small>GDB</small> generates a core file +from the current process state. +</p> +<p>The memory tag data will be used so developers can display the memory +tags from a particular memory region (using the ‘<samp>m</samp>’ modifier to the +<code>x</code> command, using the <code>print</code> command or using the various +<code>memory-tag</code> subcommands. +</p> +<p>In the case of a crash, <small>GDB</small> will attempt to retrieve the memory tag +information automatically from the core file, and will show one of the above +messages depending on whether the synchronous or asynchronous mode is selected. +See <a href="Memory-Tagging.html#Memory-Tagging">Memory Tagging</a>. See <a href="Memory.html#Memory">Memory</a>. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="i386.html#i386" accesskey="n" rel="next">i386</a>, Up: <a href="Architectures.html#Architectures" accesskey="u" rel="up">Architectures</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> |