liberatehongkong
/
linux-kernel-module-cheat


			
				
					
						
						
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<meta name="description" content="The perfect emulation setup to study and develop the &lt;&lt;linux-kernel&gt;&gt; v5.9.2, kernel modules, &lt;&lt;qemu-buildroot-setup,QEMU&gt;&gt;, &lt;&lt;gem5-buildroot-setup,gem5&gt;&gt; and x86_64, ARMv7 and ARMv8 &lt;&lt;userland-assembly,userland&gt;&gt; and &lt;&lt;baremetal-setup,baremetal&gt;&gt; assembly, &lt;&lt;c,ANSI C&gt;&gt;, &lt;&lt;cpp,C++&gt;&gt; and &lt;&lt;posix,POSIX&gt;&gt;. &lt;&lt;gdb&gt;&gt; and &lt;&lt;kgdb&gt;&gt; just work. Powered by &lt;&lt;about-the-qemu-buildroot-setup,Buildroot&gt;&gt; and &lt;&lt;about-the-baremetal-setup,crosstool-NG&gt;&gt;. Highly automated. Thoroughly documented. Automated &lt;&lt;test-this-repo,tests&gt;&gt;. "Tested" in an Ubuntu 20.04 host.">
<title>Linux Kernel Module Cheat</title>
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</head>
<body id="path-properties" class="article">
<div id="header">
<h1>Linux Kernel Module Cheat</h1>
</div>
<div id="content">
<div class="sect3">
<h4 id="path-properties"><a class="anchor" href="#path-properties"></a><a class="link" href="#path-properties">38.15.7. path_properties.py</a></h4>
<div class="paragraph">
<p>In order to build and run each userland and <a href="baremetal-setup.html">baremetal</a> example properly, we need per-file metadata such as compiler flags and required number of cores.</p>
</div>
<div class="paragraph">
<p>This data is stored is stored in <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/path_properties.py">path_properties.py</a> at <code>path_properties_tuples</code>.</p>
</div>
<div class="paragraph">
<p>Maybe we should embed it magically into source files directories to make it easier to see? But one big Python dict was easier to implement so we started like this. And it allows factoring chunks out easily.</p>
</div>
<div class="paragraph">
<p>The format is as follows:</p>
</div>
<div class="literalblock">
<div class="content">
<pre>'path_component': (
    {'property': value},
    {
        'child_path_component':
        {
            {'child_property': },
            {}
        }
    }
)</pre>
</div>
</div>
<div class="paragraph">
<p>and as a shortcut, paths that don&#8217;t have any children can be written directly as:</p>
</div>
<div class="literalblock">
<div class="content">
<pre>'path_component': {'property': value}</pre>
</div>
</div>
<div class="paragraph">
<p>Properties of parent directories apply to all children.</p>
</div>
<div class="paragraph">
<p>Lists coming from parent directories are extended instead of overwritten by children, this is especially useful for C compiler flags.</p>
</div>
<div class="paragraph">
<p>To quickly determine which properties a path has, you can use <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/getprops">getprops</a>, e.g.:</p>
</div>
<div class="literalblock">
<div class="content">
<pre>./getprops userland/c/hello.c</pre>
</div>
</div>
<div class="paragraph">
<p>which outputs values such as:</p>
</div>
<div class="literalblock">
<div class="content">
<pre>allowed_archs=None
allowed_emulators=None
arm_aarch32=False
arm_sve=False
baremetal=True</pre>
</div>
</div>
<div class="ulist">
<ul>
</ul>
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<div class="paragraph nav-footer">
<p>← Previous: <a href="lkmc-home.html">lkmc_home</a> | ↑ Up: <a href="directory-structure.html">Directory structure</a> | ⌂ Home: <a href="README.html">Linux Kernel Module Cheat</a> | Next: <a href="rand-check-out.html">rand_check.out</a> →</p>
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