diff --git a/index.html b/index.html
index 23eec9a..4bbbe79 100644
--- a/index.html
+++ b/index.html
@@ -5,7 +5,7 @@
 <meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <meta name="generator" content="Asciidoctor 2.0.10">
-<meta name="description" content="The perfect emulation setup to study and develop the &lt;&lt;linux-kernel&gt;&gt; v5.1, 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 18.04 host.">
+<meta name="description" content="The perfect emulation setup to study and develop the &lt;&lt;linux-kernel&gt;&gt; v5.2.1, 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 18.04 host.">
 <title>Linux Kernel Module Cheat</title>
 <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700">
 <style>
@@ -445,13 +445,13 @@ body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-b
 <div id="preamble">
 <div class="sectionbody">
 <div class="paragraph">
-<p>The perfect emulation setup to study and develop the <a href="#linux-kernel">Linux kernel</a> v5.1, kernel modules, <a href="#qemu-buildroot-setup">QEMU</a>, <a href="#gem5-buildroot-setup">gem5</a> and x86_64, ARMv7 and ARMv8 <a href="#userland-assembly">userland</a> and <a href="#baremetal-setup">baremetal</a> assembly, <a href="#c">ANSI C</a>, <a href="#cpp">C++</a> and <a href="#posix">POSIX</a>. <a href="#gdb">GDB step debug</a> and <a href="#kgdb">KGDB</a> just work. Powered by <a href="#about-the-qemu-buildroot-setup">Buildroot</a> and <a href="#about-the-baremetal-setup">crosstool-NG</a>.  Highly automated. Thoroughly documented. Automated <a href="#test-this-repo">tests</a>. "Tested" in an Ubuntu 18.04 host.</p>
+<p>The perfect emulation setup to study and develop the <a href="#linux-kernel">Linux kernel</a> v5.2.1, kernel modules, <a href="#qemu-buildroot-setup">QEMU</a>, <a href="#gem5-buildroot-setup">gem5</a> and x86_64, ARMv7 and ARMv8 <a href="#userland-assembly">userland</a> and <a href="#baremetal-setup">baremetal</a> assembly, <a href="#c">ANSI C</a>, <a href="#cpp">C++</a> and <a href="#posix">POSIX</a>. <a href="#gdb">GDB step debug</a> and <a href="#kgdb">KGDB</a> just work. Powered by <a href="#about-the-qemu-buildroot-setup">Buildroot</a> and <a href="#about-the-baremetal-setup">crosstool-NG</a>.  Highly automated. Thoroughly documented. Automated <a href="#test-this-repo">tests</a>. "Tested" in an Ubuntu 18.04 host.</p>
 </div>
 <div class="paragraph">
 <p>TL;DR: <a href="#qemu-buildroot-setup-getting-started">QEMU Buildroot setup getting started</a></p>
 </div>
 <div class="paragraph">
-<p>The source code for this page is located at: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat" class="bare">https://github.com/cirosantilli/linux-kernel-module-cheat</a>. Due to <a href="https://github.com/isaacs/github/issues/1610">a GitHub limitation</a>, this README is too long and not fully rendered on github.com. Either use: <a href="https://cirosantilli.com/linux-kernel-module-cheat" class="bare">https://cirosantilli.com/linux-kernel-module-cheat</a> or <a href="#build-the-documentation">build the docs yourself</a>.</p>
+<p>The source code for this page is located at: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat" class="bare">https://github.com/cirosantilli/linux-kernel-module-cheat</a>. Due to <a href="https://github.com/isaacs/github/issues/1610">a GitHub limitation</a>, this README is too long and not fully rendered on github.com. Either use: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/README.adoc">README.adoc</a>, <a href="https://cirosantilli.com/linux-kernel-module-cheat" class="bare">https://cirosantilli.com/linux-kernel-module-cheat</a> or <a href="#build-the-documentation">build the docs yourself</a>.</p>
 </div>
 <div id="toc" class="toc">
 <div id="toctitle" class="title"></div>
@@ -795,7 +795,11 @@ body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-b
 <li><a href="#kernel-version">15.2. Kernel version</a>
 <ul class="sectlevel3">
 <li><a href="#find-the-kernel-version">15.2.1. Find the kernel version</a></li>
-<li><a href="#update-the-linux-kernel">15.2.2. Update the Linux kernel</a></li>
+<li><a href="#update-the-linux-kernel">15.2.2. Update the Linux kernel</a>
+<ul class="sectlevel4">
+<li><a href="#update-the-linux-kernel-lkmc-procedure">15.2.2.1. Update the Linux kernel LKMC procedure</a></li>
+</ul>
+</li>
 <li><a href="#downgrade-the-linux-kernel">15.2.3. Downgrade the Linux kernel</a></li>
 </ul>
 </li>
@@ -1191,14 +1195,20 @@ body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-b
 </li>
 <li><a href="#cpp">20.2. C++</a>
 <ul class="sectlevel3">
-<li><a href="#c-standards">20.2.1. C++ standards</a>
+<li><a href="#cpp-multithreading">20.2.1. C++ multithreading</a></li>
+<li><a href="#c-standards">20.2.2. C++ standards</a>
 <ul class="sectlevel4">
-<li><a href="#cpp17">20.2.1.1. C++17 N4659 standards draft</a></li>
+<li><a href="#cpp17">20.2.2.1. C++17 N4659 standards draft</a></li>
 </ul>
 </li>
 </ul>
 </li>
-<li><a href="#posix">20.3. POSIX</a></li>
+<li><a href="#posix">20.3. POSIX</a>
+<ul class="sectlevel3">
+<li><a href="#sysconf">20.3.1. sysconf</a></li>
+</ul>
+</li>
+<li><a href="#userland-multithreading">20.4. Userland multithreading</a></li>
 </ul>
 </li>
 <li><a href="#userland-assembly">21. Userland assembly</a>
@@ -1334,7 +1344,11 @@ body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-b
 </li>
 </ul>
 </li>
-<li><a href="#x86-lock-prefix">22.14. x86 LOCK prefix</a></li>
+<li><a href="#x86-thread-synchronization-primitives">22.14. x86 thread synchronization primitives</a>
+<ul class="sectlevel3">
+<li><a href="#x86-lock-prefix">22.14.1. x86 LOCK prefix</a></li>
+</ul>
+</li>
 <li><a href="#x86-assembly-bibliography">22.15. x86 assembly bibliography</a>
 <ul class="sectlevel3">
 <li><a href="#x86-official-bibliography">22.15.1. x86 official bibliography</a>
@@ -1367,6 +1381,7 @@ body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-b
 <li><a href="#arm-instruction-encodings">23.1.3. ARM instruction encodings</a>
 <ul class="sectlevel4">
 <li><a href="#arm-thumb-encoding">23.1.3.1. ARM Thumb encoding</a></li>
+<li><a href="#arm-big-endian-mode">23.1.3.2. ARM big endian mode</a></li>
 </ul>
 </li>
 </ul>
@@ -1516,232 +1531,243 @@ body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-b
 <li><a href="#armarm8">23.8.2.2. ARMv8 architecture reference manual</a></li>
 <li><a href="#armarm8-db">23.8.2.3. ARMv8 architecture reference manual db</a></li>
 <li><a href="#armv8-programmers-guide">23.8.2.4. Programmer&#8217;s Guide for ARMv8-A</a></li>
-<li><a href="#arm-processor-documentation">23.8.2.5. ARM processor documentation</a></li>
-<li><a href="#arm-cortex15-trm">23.8.2.6. ARM Cortex-A15 MPCore Processor Technical Reference Manual r4p0</a></li>
-</ul>
-</li>
-</ul>
-</li>
-</ul>
-</li>
-<li><a href="#ieee-754">24. IEEE 754</a></li>
-<li><a href="#baremetal">25. Baremetal</a>
-<ul class="sectlevel2">
-<li><a href="#baremetal-gdb-step-debug">25.1. Baremetal GDB step debug</a></li>
-<li><a href="#baremetal-bootloaders">25.2. Baremetal bootloaders</a></li>
-<li><a href="#semihosting">25.3. Semihosting</a>
-<ul class="sectlevel3">
-<li><a href="#gem5-semihosting">25.3.1. gem5 semihosting</a></li>
-</ul>
-</li>
-<li><a href="#gem5-baremetal-carriage-return">25.4. gem5 baremetal carriage return</a></li>
-<li><a href="#baremetal-host-packaged-toolchain">25.5. Baremetal host packaged toolchain</a></li>
-<li><a href="#baremetal-cpp">25.6. Baremetal C++</a></li>
-<li><a href="#gdb-builtin-cpu-simulator">25.7. GDB builtin CPU simulator</a>
-<ul class="sectlevel3">
-<li><a href="#gdb-builtin-cpu-simulator-userland">25.7.1. GDB builtin CPU simulator userland</a></li>
-</ul>
-</li>
-<li><a href="#arm-baremetal">25.8. ARM baremetal</a>
-<ul class="sectlevel3">
-<li><a href="#arm-exception-levels">25.8.1. ARM exception levels</a></li>
-<li><a href="#arm-svc-instruction">25.8.2. ARM SVC instruction</a></li>
-<li><a href="#arm-multicore">25.8.3. ARM multicore</a>
-<ul class="sectlevel4">
-<li><a href="#arm-wfe-and-sev-instructions">25.8.3.1. ARM WFE and SEV instructions</a></li>
-<li><a href="#arm-psci">25.8.3.2. ARM PSCI</a></li>
-<li><a href="#arm-dmb-instruction">25.8.3.3. ARM DMB instruction</a></li>
-</ul>
-</li>
-<li><a href="#arm-timer">25.8.4. ARM timer</a></li>
-<li><a href="#arm-baremetal-bibliography">25.8.5. ARM baremetal bibliography</a>
-<ul class="sectlevel4">
-<li><a href="#nienfengyaoarmv8-bare-metal">25.8.5.1. NienfengYao/armv8-bare-metal</a></li>
-<li><a href="#tukl-msdgem5-bare-metal">25.8.5.2. tukl-msd/gem5.bare-metal</a></li>
-</ul>
-</li>
-</ul>
-</li>
-<li><a href="#how-we-got-some-baremetal-stuff-to-work">25.9. How we got some baremetal stuff to work</a>
-<ul class="sectlevel3">
-<li><a href="#find-the-uart-address">25.9.1. Find the UART address</a></li>
-<li><a href="#aarch64-baremetal-neon-setup">25.9.2. aarch64 baremetal NEON setup</a></li>
-</ul>
-</li>
-<li><a href="#baremetal-tests">25.10. Baremetal tests</a></li>
-</ul>
-</li>
-<li><a href="#android">26. Android</a>
-<ul class="sectlevel2">
-<li><a href="#android-image-structure">26.1. Android image structure</a>
-<ul class="sectlevel3">
-<li><a href="#android-images-read-only">26.1.1. Android images read-only</a></li>
-<li><a href="#android-data-partition">26.1.2. Android /data partition</a></li>
-</ul>
-</li>
-<li><a href="#install-android-apps">26.2. Install Android apps</a></li>
-<li><a href="#android-init">26.3. Android init</a></li>
-</ul>
-</li>
-<li><a href="#benchmark-this-repo">27. Benchmark this repo</a>
-<ul class="sectlevel2">
-<li><a href="#continuous-integraion">27.1. Continuous integraion</a>
-<ul class="sectlevel3">
-<li><a href="#travis">27.1.1. Travis</a></li>
-<li><a href="#circleci">27.1.2. CircleCI</a></li>
-</ul>
-</li>
-<li><a href="#benchmark-this-repo-benchmarks">27.2. Benchmark this repo benchmarks</a>
-<ul class="sectlevel3">
-<li><a href="#benchmark-linux-kernel-boot">27.2.1. Benchmark Linux kernel boot</a>
-<ul class="sectlevel4">
-<li><a href="#gem5-arm-hpi-boot-takes-much-longer-than-aarch64">27.2.1.1. gem5 arm HPI boot takes much longer than aarch64</a></li>
-<li><a href="#gem5-x86_64-derivo3cpu-boot-panics">27.2.1.2. gem5 x86_64 DerivO3CPU boot panics</a></li>
-</ul>
-</li>
-<li><a href="#benchmark-builds">27.2.2. Benchmark builds</a>
-<ul class="sectlevel4">
-<li><a href="#find-which-packages-are-making-the-build-slow-and-big">27.2.2.1. Find which packages are making the build slow and big</a>
+<li><a href="#arm-a64-instruction-set-architecture-future-architecture-technologies-in-the-a-architecture-profile-documentation">23.8.2.5. Arm A64 Instruction Set Architecture: Future Architecture Technologies in the A architecture profile Documentation</a></li>
+<li><a href="#arm-processor-documentation">23.8.2.6. ARM processor documentation</a>
 <ul class="sectlevel5">
-<li><a href="#prebuilt-toolchain">27.2.2.1.1. Buildroot use prebuilt host toolchain</a></li>
-</ul>
-</li>
-<li><a href="#benchmark-buildroot-build-baseline">27.2.2.2. Benchmark Buildroot build baseline</a></li>
-<li><a href="#benchmark-gem5-build">27.2.2.3. Benchmark gem5 build</a>
-<ul class="sectlevel5">
-<li><a href="#benchmark-gem5-single-file-change-rebuild-time">27.2.2.3.1. Benchmark gem5 single file change rebuild time</a></li>
+<li><a href="#arm-cortex15-trm">23.8.2.6.1. ARM Cortex-A15 MPCore Processor Technical Reference Manual r4p0</a></li>
 </ul>
 </li>
 </ul>
 </li>
 </ul>
 </li>
-<li><a href="#benchmark-machines">27.3. Benchmark machines</a>
-<ul class="sectlevel3">
-<li><a href="#p51">27.3.1. P51</a></li>
 </ul>
 </li>
-<li><a href="#benchmark-internets">27.4. Benchmark Internets</a>
-<ul class="sectlevel3">
-<li><a href="#38mbps-internet">27.4.1. 38Mbps internet</a></li>
-</ul>
-</li>
-<li><a href="#benchmark-this-repo-bibliography">27.5. Benchmark this repo bibliography</a></li>
-</ul>
-</li>
-<li><a href="#about-this-repo">28. About this repo</a>
+<li><a href="#elf">24. ELF</a></li>
+<li><a href="#ieee-754">25. IEEE 754</a></li>
+<li><a href="#baremetal">26. Baremetal</a>
 <ul class="sectlevel2">
-<li><a href="#supported-hosts">28.1. Supported hosts</a></li>
-<li><a href="#common-build-issues">28.2. Common build issues</a>
+<li><a href="#baremetal-gdb-step-debug">26.1. Baremetal GDB step debug</a></li>
+<li><a href="#baremetal-bootloaders">26.2. Baremetal bootloaders</a></li>
+<li><a href="#semihosting">26.3. Semihosting</a>
 <ul class="sectlevel3">
-<li><a href="#put-source-uris-in-sources">28.2.1. You must put some 'source' URIs in your sources.list</a></li>
-<li><a href="#build-from-downloaded-source-zip-files">28.2.2. Build from downloaded source zip files</a></li>
+<li><a href="#gem5-semihosting">26.3.1. gem5 semihosting</a></li>
 </ul>
 </li>
-<li><a href="#run-command-after-boot">28.3. Run command after boot</a></li>
-<li><a href="#default-command-line-arguments">28.4. Default command line arguments</a></li>
-<li><a href="#build-the-documentation">28.5. Build the documentation</a>
+<li><a href="#gem5-baremetal-carriage-return">26.4. gem5 baremetal carriage return</a></li>
+<li><a href="#baremetal-host-packaged-toolchain">26.5. Baremetal host packaged toolchain</a></li>
+<li><a href="#baremetal-cpp">26.6. Baremetal C++</a></li>
+<li><a href="#gdb-builtin-cpu-simulator">26.7. GDB builtin CPU simulator</a>
 <ul class="sectlevel3">
-<li><a href="#documentation-verification">28.5.1. Documentation verification</a>
+<li><a href="#gdb-builtin-cpu-simulator-userland">26.7.1. GDB builtin CPU simulator userland</a></li>
+</ul>
+</li>
+<li><a href="#arm-baremetal">26.8. ARM baremetal</a>
+<ul class="sectlevel3">
+<li><a href="#arm-exception-levels">26.8.1. ARM exception levels</a></li>
+<li><a href="#arm-svc-instruction">26.8.2. ARM SVC instruction</a>
 <ul class="sectlevel4">
-<li><a href="#asciidoctor-extract-link-targets">28.5.1.1. asciidoctor/extract-link-targets</a></li>
-<li><a href="#asciidoctor-extract-header-ids">28.5.1.2. asciidoctor/extract-header-ids</a></li>
+<li><a href="#arm-esr-register">26.8.2.1. ARM ESR register</a></li>
+<li><a href="#arm-elr-register">26.8.2.2. ARM ELR register</a></li>
 </ul>
 </li>
-</ul>
-</li>
-<li><a href="#asciidoctor-link-target-up-rb">28.6. asciidoctor/link-target-up.rb</a>
-<ul class="sectlevel3">
-<li><a href="#github-pages">28.6.1. GitHub pages</a></li>
-</ul>
-</li>
-<li><a href="#clean-the-build">28.7. Clean the build</a></li>
-<li><a href="#ccache">28.8. ccache</a></li>
-<li><a href="#rebuild-buildroot-while-running">28.9. Rebuild Buildroot while running</a></li>
-<li><a href="#simultaneous-runs">28.10. Simultaneous runs</a></li>
-<li><a href="#build-variants">28.11. Build variants</a>
-<ul class="sectlevel3">
-<li><a href="#linux-kernel-build-variants">28.11.1. Linux kernel build variants</a></li>
-<li><a href="#qemu-build-variants">28.11.2. QEMU build variants</a></li>
-<li><a href="#gem5-build-variants">28.11.3. gem5 build variants</a>
+<li><a href="#arm-multicore">26.8.3. ARM multicore</a>
 <ul class="sectlevel4">
-<li><a href="#gem5-worktree">28.11.3.1. gem5 worktree</a></li>
-<li><a href="#gem5-private-source-trees">28.11.3.2. gem5 private source trees</a></li>
-<li><a href="#gem5-debug-build">28.11.3.3. gem5 debug build</a></li>
+<li><a href="#arm-wfe-and-sev-instructions">26.8.3.1. ARM WFE and SEV instructions</a></li>
+<li><a href="#arm-psci">26.8.3.2. ARM PSCI</a></li>
+<li><a href="#arm-dmb-instruction">26.8.3.3. ARM DMB instruction</a></li>
 </ul>
 </li>
-<li><a href="#buildroot-build-variants">28.11.4. Buildroot build variants</a></li>
-</ul>
-</li>
-<li><a href="#directory-structure">28.12. Directory structure</a>
-<ul class="sectlevel3">
-<li><a href="#lkmc-directory">28.12.1. lkmc directory</a>
+<li><a href="#arm-timer">26.8.4. ARM timer</a></li>
+<li><a href="#arm-paging">26.8.5. ARM paging</a></li>
+<li><a href="#arm-baremetal-bibliography">26.8.6. ARM baremetal bibliography</a>
 <ul class="sectlevel4">
-<li><a href="#userland-objects-vs-header-only">28.12.1.1. Userland objects vs header-only</a></li>
+<li><a href="#nienfengyaoarmv8-bare-metal">26.8.6.1. NienfengYao/armv8-bare-metal</a></li>
+<li><a href="#tukl-msdgem5-bare-metal">26.8.6.2. tukl-msd/gem5.bare-metal</a></li>
 </ul>
 </li>
-<li><a href="#buildroot_packages-directory">28.12.2. buildroot_packages directory</a>
-<ul class="sectlevel4">
-<li><a href="#kernel_modules-buildroot-package">28.12.2.1. kernel_modules buildroot package</a></li>
 </ul>
 </li>
-<li><a href="#patches-directory">28.12.3. patches directory</a>
-<ul class="sectlevel4">
-<li><a href="#patches-global-directory">28.12.3.1. patches/global directory</a></li>
-<li><a href="#patches-manual-directory">28.12.3.2. patches/manual directory</a></li>
-</ul>
-</li>
-<li><a href="#rootfs_overlay">28.12.4. rootfs_overlay</a></li>
-<li><a href="#lkmc-c">28.12.5. lkmc.c</a></li>
-<li><a href="#rand_check-out">28.12.6. rand_check.out</a></li>
-<li><a href="#lkmc_home">28.12.7. lkmc_home</a></li>
-</ul>
-</li>
-<li><a href="#test-this-repo">28.13. Test this repo</a>
+<li><a href="#how-we-got-some-baremetal-stuff-to-work">26.9. How we got some baremetal stuff to work</a>
 <ul class="sectlevel3">
-<li><a href="#automated-tests">28.13.1. Automated tests</a>
+<li><a href="#find-the-uart-address">26.9.1. Find the UART address</a></li>
+<li><a href="#aarch64-baremetal-neon-setup">26.9.2. aarch64 baremetal NEON setup</a></li>
+</ul>
+</li>
+<li><a href="#baremetal-tests">26.10. Baremetal tests</a></li>
+</ul>
+</li>
+<li><a href="#android">27. Android</a>
+<ul class="sectlevel2">
+<li><a href="#android-image-structure">27.1. Android image structure</a>
+<ul class="sectlevel3">
+<li><a href="#android-images-read-only">27.1.1. Android images read-only</a></li>
+<li><a href="#android-data-partition">27.1.2. Android /data partition</a></li>
+</ul>
+</li>
+<li><a href="#install-android-apps">27.2. Install Android apps</a></li>
+<li><a href="#android-init">27.3. Android init</a></li>
+</ul>
+</li>
+<li><a href="#benchmark-this-repo">28. Benchmark this repo</a>
+<ul class="sectlevel2">
+<li><a href="#continuous-integraion">28.1. Continuous integraion</a>
+<ul class="sectlevel3">
+<li><a href="#travis">28.1.1. Travis</a></li>
+<li><a href="#circleci">28.1.2. CircleCI</a></li>
+</ul>
+</li>
+<li><a href="#benchmark-this-repo-benchmarks">28.2. Benchmark this repo benchmarks</a>
+<ul class="sectlevel3">
+<li><a href="#benchmark-linux-kernel-boot">28.2.1. Benchmark Linux kernel boot</a>
 <ul class="sectlevel4">
-<li><a href="#test-arch-and-emulator-selection">28.13.1.1. Test arch and emulator selection</a></li>
-<li><a href="#quit-on-fail">28.13.1.2. Quit on fail</a></li>
-<li><a href="#test-userland-in-full-system">28.13.1.3. Test userland in full system</a></li>
-<li><a href="#gdb-tests">28.13.1.4. GDB tests</a></li>
-<li><a href="#magic-failure-string">28.13.1.5. Magic failure string</a></li>
+<li><a href="#gem5-arm-hpi-boot-takes-much-longer-than-aarch64">28.2.1.1. gem5 arm HPI boot takes much longer than aarch64</a></li>
+<li><a href="#gem5-x86_64-derivo3cpu-boot-panics">28.2.1.2. gem5 x86_64 DerivO3CPU boot panics</a></li>
 </ul>
 </li>
-<li><a href="#non-automated-tests">28.13.2. Non-automated tests</a>
+<li><a href="#benchmark-builds">28.2.2. Benchmark builds</a>
 <ul class="sectlevel4">
-<li><a href="#test-gdb-linux-kernel">28.13.2.1. Test GDB Linux kernel</a></li>
-<li><a href="#test-the-internet">28.13.2.2. Test the Internet</a></li>
-<li><a href="#cli-script-tests">28.13.2.3. CLI script tests</a></li>
+<li><a href="#find-which-packages-are-making-the-build-slow-and-big">28.2.2.1. Find which packages are making the build slow and big</a>
+<ul class="sectlevel5">
+<li><a href="#prebuilt-toolchain">28.2.2.1.1. Buildroot use prebuilt host toolchain</a></li>
+</ul>
+</li>
+<li><a href="#benchmark-buildroot-build-baseline">28.2.2.2. Benchmark Buildroot build baseline</a></li>
+<li><a href="#benchmark-gem5-build">28.2.2.3. Benchmark gem5 build</a>
+<ul class="sectlevel5">
+<li><a href="#benchmark-gem5-single-file-change-rebuild-time">28.2.2.3.1. Benchmark gem5 single file change rebuild time</a></li>
 </ul>
 </li>
 </ul>
 </li>
-<li><a href="#bisection">28.14. Bisection</a></li>
-<li><a href="#path-properties">28.15. path_properties</a></li>
-<li><a href="#update-a-forked-submodule">28.16. Update a forked submodule</a></li>
-<li><a href="#release">28.17. Release</a>
+</ul>
+</li>
+<li><a href="#benchmark-machines">28.3. Benchmark machines</a>
 <ul class="sectlevel3">
-<li><a href="#release-procedure">28.17.1. Release procedure</a></li>
-<li><a href="#release-zip">28.17.2. release-zip</a></li>
-<li><a href="#release-upload">28.17.3. release-upload</a></li>
+<li><a href="#p51">28.3.1. P51</a></li>
 </ul>
 </li>
-<li><a href="#design-rationale">28.18. Design rationale</a>
+<li><a href="#benchmark-internets">28.4. Benchmark Internets</a>
 <ul class="sectlevel3">
-<li><a href="#design-goals">28.18.1. Design goals</a></li>
-<li><a href="#setup-trade-offs">28.18.2. Setup trade-offs</a></li>
-<li><a href="#resource-tradeoff-guidelines">28.18.3. Resource tradeoff guidelines</a></li>
-<li><a href="#linux-distro-choice">28.18.4. Linux distro choice</a></li>
+<li><a href="#38mbps-internet">28.4.1. 38Mbps internet</a></li>
 </ul>
 </li>
-<li><a href="#soft-topics">28.19. Soft topics</a>
+<li><a href="#benchmark-this-repo-bibliography">28.5. Benchmark this repo bibliography</a></li>
+</ul>
+</li>
+<li><a href="#about-this-repo">29. About this repo</a>
+<ul class="sectlevel2">
+<li><a href="#supported-hosts">29.1. Supported hosts</a></li>
+<li><a href="#common-build-issues">29.2. Common build issues</a>
 <ul class="sectlevel3">
-<li><a href="#fairy-tale">28.19.1. Fairy tale</a></li>
-<li><a href="#should-you-waste-your-life-with-systems-programming">28.19.2. Should you waste your life with systems programming?</a></li>
+<li><a href="#put-source-uris-in-sources">29.2.1. You must put some 'source' URIs in your sources.list</a></li>
+<li><a href="#build-from-downloaded-source-zip-files">29.2.2. Build from downloaded source zip files</a></li>
 </ul>
 </li>
-<li><a href="#bibliography">28.20. Bibliography</a></li>
+<li><a href="#run-command-after-boot">29.3. Run command after boot</a></li>
+<li><a href="#default-command-line-arguments">29.4. Default command line arguments</a></li>
+<li><a href="#build-the-documentation">29.5. Build the documentation</a>
+<ul class="sectlevel3">
+<li><a href="#documentation-verification">29.5.1. Documentation verification</a>
+<ul class="sectlevel4">
+<li><a href="#asciidoctor-extract-link-targets">29.5.1.1. asciidoctor/extract-link-targets</a></li>
+<li><a href="#asciidoctor-extract-header-ids">29.5.1.2. asciidoctor/extract-header-ids</a></li>
+</ul>
+</li>
+</ul>
+</li>
+<li><a href="#asciidoctor-link-target-up-rb">29.6. asciidoctor/link-target-up.rb</a>
+<ul class="sectlevel3">
+<li><a href="#github-pages">29.6.1. GitHub pages</a></li>
+</ul>
+</li>
+<li><a href="#clean-the-build">29.7. Clean the build</a></li>
+<li><a href="#ccache">29.8. ccache</a></li>
+<li><a href="#rebuild-buildroot-while-running">29.9. Rebuild Buildroot while running</a></li>
+<li><a href="#simultaneous-runs">29.10. Simultaneous runs</a></li>
+<li><a href="#build-variants">29.11. Build variants</a>
+<ul class="sectlevel3">
+<li><a href="#linux-kernel-build-variants">29.11.1. Linux kernel build variants</a></li>
+<li><a href="#qemu-build-variants">29.11.2. QEMU build variants</a></li>
+<li><a href="#gem5-build-variants">29.11.3. gem5 build variants</a>
+<ul class="sectlevel4">
+<li><a href="#gem5-worktree">29.11.3.1. gem5 worktree</a></li>
+<li><a href="#gem5-private-source-trees">29.11.3.2. gem5 private source trees</a></li>
+<li><a href="#gem5-debug-build">29.11.3.3. gem5 debug build</a></li>
+</ul>
+</li>
+<li><a href="#buildroot-build-variants">29.11.4. Buildroot build variants</a></li>
+</ul>
+</li>
+<li><a href="#directory-structure">29.12. Directory structure</a>
+<ul class="sectlevel3">
+<li><a href="#lkmc-directory">29.12.1. lkmc directory</a>
+<ul class="sectlevel4">
+<li><a href="#userland-objects-vs-header-only">29.12.1.1. Userland objects vs header-only</a></li>
+</ul>
+</li>
+<li><a href="#buildroot_packages-directory">29.12.2. buildroot_packages directory</a>
+<ul class="sectlevel4">
+<li><a href="#kernel_modules-buildroot-package">29.12.2.1. kernel_modules buildroot package</a></li>
+</ul>
+</li>
+<li><a href="#patches-directory">29.12.3. patches directory</a>
+<ul class="sectlevel4">
+<li><a href="#patches-global-directory">29.12.3.1. patches/global directory</a></li>
+<li><a href="#patches-manual-directory">29.12.3.2. patches/manual directory</a></li>
+</ul>
+</li>
+<li><a href="#rootfs_overlay">29.12.4. rootfs_overlay</a></li>
+<li><a href="#lkmc-c">29.12.5. lkmc.c</a></li>
+<li><a href="#rand_check-out">29.12.6. rand_check.out</a></li>
+<li><a href="#lkmc_home">29.12.7. lkmc_home</a></li>
+</ul>
+</li>
+<li><a href="#test-this-repo">29.13. Test this repo</a>
+<ul class="sectlevel3">
+<li><a href="#automated-tests">29.13.1. Automated tests</a>
+<ul class="sectlevel4">
+<li><a href="#test-arch-and-emulator-selection">29.13.1.1. Test arch and emulator selection</a></li>
+<li><a href="#quit-on-fail">29.13.1.2. Quit on fail</a></li>
+<li><a href="#test-userland-in-full-system">29.13.1.3. Test userland in full system</a></li>
+<li><a href="#gdb-tests">29.13.1.4. GDB tests</a></li>
+<li><a href="#magic-failure-string">29.13.1.5. Magic failure string</a></li>
+</ul>
+</li>
+<li><a href="#non-automated-tests">29.13.2. Non-automated tests</a>
+<ul class="sectlevel4">
+<li><a href="#test-gdb-linux-kernel">29.13.2.1. Test GDB Linux kernel</a></li>
+<li><a href="#test-the-internet">29.13.2.2. Test the Internet</a></li>
+<li><a href="#cli-script-tests">29.13.2.3. CLI script tests</a></li>
+</ul>
+</li>
+</ul>
+</li>
+<li><a href="#bisection">29.14. Bisection</a></li>
+<li><a href="#path-properties">29.15. path_properties</a></li>
+<li><a href="#update-a-forked-submodule">29.16. Update a forked submodule</a></li>
+<li><a href="#release">29.17. Release</a>
+<ul class="sectlevel3">
+<li><a href="#release-procedure">29.17.1. Release procedure</a></li>
+<li><a href="#release-zip">29.17.2. release-zip</a></li>
+<li><a href="#release-upload">29.17.3. release-upload</a></li>
+</ul>
+</li>
+<li><a href="#design-rationale">29.18. Design rationale</a>
+<ul class="sectlevel3">
+<li><a href="#design-goals">29.18.1. Design goals</a></li>
+<li><a href="#setup-trade-offs">29.18.2. Setup trade-offs</a></li>
+<li><a href="#resource-tradeoff-guidelines">29.18.3. Resource tradeoff guidelines</a></li>
+<li><a href="#linux-distro-choice">29.18.4. Linux distro choice</a></li>
+</ul>
+</li>
+<li><a href="#soft-topics">29.19. Soft topics</a>
+<ul class="sectlevel3">
+<li><a href="#fairy-tale">29.19.1. Fairy tale</a></li>
+<li><a href="#should-you-waste-your-life-with-systems-programming">29.19.2. Should you waste your life with systems programming?</a></li>
+</ul>
+</li>
+<li><a href="#bibliography">29.20. Bibliography</a></li>
 </ul>
 </li>
 </ul>
@@ -3088,7 +3114,7 @@ dmesg</pre>
 <div class="sect3">
 <h4 id="userland-setup-getting-started"><a class="anchor" href="#userland-setup-getting-started"></a><a class="link" href="#userland-setup-getting-started">1.6.2. Userland setup getting started</a></h4>
 <div class="paragraph">
-<p>There are several ways to run our userland content, notably:</p>
+<p>There are several ways to run our <a href="#userland-content">Userland content</a>, notably:</p>
 </div>
 <div class="ulist">
 <ul>
@@ -8314,8 +8340,7 @@ git -C "$(./getvar linux_source_dir)" checkout -
 [    0.066438]  ret_from_fork+0x10/0x1c
 [    0.066444] hdlcd 2b000000.hdlcd: Failed to set initial hw configuration.
 [    0.066470] hdlcd 2b000000.hdlcd: master bind failed: -12
-[    0.066477] hdlcd: probe of 2b000000.hdlcd failed with error -12
-[</pre>
+[    0.066477] hdlcd: probe of 2b000000.hdlcd failed with error -12</pre>
 </div>
 </div>
 <div class="paragraph">
@@ -8355,7 +8380,7 @@ xeyes</pre>
 </div>
 </div>
 <div class="paragraph">
-<p>Outcome: <a href="#image-x11">X11 Buildroot graphical user interface screenshot</a></p>
+<p>Outcome: <a href="#image-x11">Figure 1, &#8220;X11 Buildroot graphical user interface screenshot&#8221;</a></p>
 </div>
 <div id="image-x11" class="imageblock">
 <div class="content">
@@ -9334,6 +9359,28 @@ git log | grep -E '    Linux [0-9]+\.' | head</pre>
 <div class="paragraph">
 <p>In case something breaks while updating the Linux kernel, you can try to bisect it to understand the root cause: <a href="#bisection">Bisection</a>.</p>
 </div>
+<div class="sect4">
+<h5 id="update-the-linux-kernel-lkmc-procedure"><a class="anchor" href="#update-the-linux-kernel-lkmc-procedure"></a><a class="link" href="#update-the-linux-kernel-lkmc-procedure">15.2.2.1. Update the Linux kernel LKMC procedure</a></h5>
+<div class="paragraph">
+<p>First, use use the branching procedure described at: <a href="#update-a-forked-submodule">Update a forked submodule</a></p>
+</div>
+<div class="paragraph">
+<p>Because the kernel is so central to this repository, almost all tests must be re-run, so basically just follow the full testing procedure described at: <a href="#test-this-repo">Test this repo</a>. The only tests that can be skipped are essentially the <a href="#baremetal">Baremetal</a> tests.</p>
+</div>
+<div class="paragraph">
+<p>Before comitting, don&#8217;t forget to update:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p>the <code>linux_kernel_version</code> constant in <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/common.py">common.py</a></p>
+</li>
+<li>
+<p>the tagline of this README</p>
+</li>
+</ul>
+</div>
+</div>
 </div>
 <div class="sect3">
 <h4 id="downgrade-the-linux-kernel"><a class="anchor" href="#downgrade-the-linux-kernel"></a><a class="link" href="#downgrade-the-linux-kernel">15.2.3. Downgrade the Linux kernel</a></h4>
@@ -16956,7 +17003,7 @@ cat /sys/devices/system/cpu/cpu0/cache/index2/size</pre>
 </div>
 <div class="literalblock">
 <div class="content">
-<pre>./gem5-bench-cache --arch aarch64
+<pre>./gem5-bench-cache -- --arch aarch64
 cat "$(./getvar --arch aarch64 run_dir)/bench-cache.txt"</pre>
 </div>
 </div>
@@ -19416,15 +19463,15 @@ git -C "$(./getvar qemu_source_dir)" checkout -
 <p>This section contains userland content, such as <a href="#c">C</a>, <a href="#cpp">C++</a> and <a href="#posix">POSIX</a> examples.</p>
 </div>
 <div class="paragraph">
+<p>Getting started at: <a href="#userland-setup">Userland setup</a></p>
+</div>
+<div class="paragraph">
 <p>Userland assembly content is located at: <a href="#userland-assembly">Userland assembly</a>. It was split from this section basically becase we were hitting the HTML <code>h6</code> limit, stupid web :-)</p>
 </div>
 <div class="paragraph">
 <p>This content makes up the bulk of the <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/">userland/</a> directory.</p>
 </div>
 <div class="paragraph">
-<p>Getting started at: <a href="#userland-setup">Userland setup</a></p>
-</div>
-<div class="paragraph">
 <p>The quickest way to run the arch agnostic examples, which comprise the majority of the examples, is natively with: <a href="#userland-setup-getting-started-natively">Userland setup getting started natively</a></p>
 </div>
 <div class="paragraph">
@@ -19600,6 +19647,12 @@ git -C "$(./getvar qemu_source_dir)" checkout -
 <li>
 <p><a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/cpp/hello.cpp">userland/cpp/hello.cpp</a></p>
 </li>
+</ul>
+</div>
+<div class="sect3">
+<h4 id="cpp-multithreading"><a class="anchor" href="#cpp-multithreading"></a><a class="link" href="#cpp-multithreading">20.2.1. C++ multithreading</a></h4>
+<div class="ulist">
+<ul>
 <li>
 <p><code>&lt;atomic&gt;</code>: <a href="#cpp17">C++17 N4659 standards draft</a> 32 "Atomic operations library"</p>
 <div class="ulist">
@@ -19612,8 +19665,9 @@ git -C "$(./getvar qemu_source_dir)" checkout -
 </li>
 </ul>
 </div>
+</div>
 <div class="sect3">
-<h4 id="c-standards"><a class="anchor" href="#c-standards"></a><a class="link" href="#c-standards">20.2.1. C++ standards</a></h4>
+<h4 id="c-standards"><a class="anchor" href="#c-standards"></a><a class="link" href="#c-standards">20.2.2. C++ standards</a></h4>
 <div class="paragraph">
 <p>Like for C, you have to pay for the standards&#8230;&#8203; insane. So we just use the closest free drafts instead.</p>
 </div>
@@ -19621,7 +19675,7 @@ git -C "$(./getvar qemu_source_dir)" checkout -
 <p><a href="https://stackoverflow.com/questions/81656/where-do-i-find-the-current-c-or-c-standard-documents" class="bare">https://stackoverflow.com/questions/81656/where-do-i-find-the-current-c-or-c-standard-documents</a></p>
 </div>
 <div class="sect4">
-<h5 id="cpp17"><a class="anchor" href="#cpp17"></a><a class="link" href="#cpp17">20.2.1.1. C++17 N4659 standards draft</a></h5>
+<h5 id="cpp17"><a class="anchor" href="#cpp17"></a><a class="link" href="#cpp17">20.2.2.1. C++17 N4659 standards draft</a></h5>
 <div class="paragraph">
 <p><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/n4659.pdf" class="bare">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/n4659.pdf</a></p>
 </div>
@@ -19646,6 +19700,58 @@ git -C "$(./getvar qemu_source_dir)" checkout -
 </li>
 </ul>
 </div>
+<div class="sect3">
+<h4 id="sysconf"><a class="anchor" href="#sysconf"></a><a class="link" href="#sysconf">20.3.1. sysconf</a></h4>
+<div class="paragraph">
+<p><a href="https://pubs.opengroup.org/onlinepubs/9699919799/functions/sysconf.html" class="bare">https://pubs.opengroup.org/onlinepubs/9699919799/functions/sysconf.html</a></p>
+</div>
+<div class="paragraph">
+<p>Examples:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p><a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/posix/sysconf.c">userland/posix/sysconf.c</a></p>
+</li>
+<li>
+<p><a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/linux/sysconf.c">userland/linux/sysconf.c</a> showcases Linux extensions to POSIX</p>
+</li>
+</ul>
+</div>
+<div class="paragraph">
+<p>Get lots of info on the system configuration.</p>
+</div>
+<div class="paragraph">
+<p>The constants can also be viewed accessed on my Ubuntu 18.04 host with:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>getconf -a</pre>
+</div>
+</div>
+<div class="paragraph">
+<p><code>getconf</code> is also specified by POSIX at: <a href="https://pubs.opengroup.org/onlinepubs/9699919799/utilities/getconf.html" class="bare">https://pubs.opengroup.org/onlinepubs/9699919799/utilities/getconf.html</a> but not the <code>-a</code> option which shows all configurations.</p>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="userland-multithreading"><a class="anchor" href="#userland-multithreading"></a><a class="link" href="#userland-multithreading">20.4. Userland multithreading</a></h3>
+<div class="paragraph">
+<p>The following sections are related to multithreading in userland:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p>&lt;cpp-multithreading&gt;</p>
+</li>
+<li>
+<p><a href="#x86-thread-synchronization-primitives">x86 thread synchronization primitives</a></p>
+</li>
+<li>
+<p><a href="#arm-lse">ARM Large System Extensions (LSE)</a></p>
+</li>
+</ul>
+</div>
 </div>
 </div>
 </div>
@@ -22429,7 +22535,9 @@ taskset -c 1 ./userland/arch/x86_64/rdtscp.out | tail -n 1</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="x86-lock-prefix"><a class="anchor" href="#x86-lock-prefix"></a><a class="link" href="#x86-lock-prefix">22.14. x86 LOCK prefix</a></h3>
+<h3 id="x86-thread-synchronization-primitives"><a class="anchor" href="#x86-thread-synchronization-primitives"></a><a class="link" href="#x86-thread-synchronization-primitives">22.14. x86 thread synchronization primitives</a></h3>
+<div class="sect3">
+<h4 id="x86-lock-prefix"><a class="anchor" href="#x86-lock-prefix"></a><a class="link" href="#x86-lock-prefix">22.14.1. x86 LOCK prefix</a></h4>
 <div class="paragraph">
 <p>Inline assembly example at: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/cpp/atomic.cpp">userland/cpp/atomic.cpp</a></p>
 </div>
@@ -22453,6 +22561,7 @@ taskset -c 1 ./userland/arch/x86_64/rdtscp.out | tail -n 1</pre>
 </ul>
 </div>
 </div>
+</div>
 <div class="sect2">
 <h3 id="x86-assembly-bibliography"><a class="anchor" href="#x86-assembly-bibliography"></a><a class="link" href="#x86-assembly-bibliography">22.15. x86 assembly bibliography</a></h3>
 <div class="sect3">
@@ -22850,6 +22959,100 @@ Bibliography: <a href="https://www.quora.com/Why-is-it-that-you-need-a-license-f
 </ul>
 </div>
 </div>
+<div class="sect4">
+<h5 id="arm-big-endian-mode"><a class="anchor" href="#arm-big-endian-mode"></a><a class="link" href="#arm-big-endian-mode">23.1.3.2. ARM big endian mode</a></h5>
+<div class="paragraph">
+<p>ARM can switch between big and little endian mode on the fly!</p>
+</div>
+<div class="paragraph">
+<p>However, everyone only uses little endian, so the big endian ecosystem is not as supported.</p>
+</div>
+<div class="paragraph">
+<p>TODO is there any advantage of using big endian?</p>
+</div>
+<div class="paragraph">
+<p>Here Peter mentions that QEMU does "support" big endian in theory, but that there are no machines for it not sure what that implies: <a href="https://stackoverflow.com/questions/41571643/emulatin-big-endian-arm-system-with-qemu" class="bare">https://stackoverflow.com/questions/41571643/emulatin-big-endian-arm-system-with-qemu</a></p>
+</div>
+<div class="paragraph">
+<p>We can try it out quickly in user mode with:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>touch userland/arch/aarch64/freestanding/linux/hello.S
+./build-userland --arch aarch64 --ccflags=-mbig-endian userland/arch/aarch64/freestanding/linux/hello.S
+./run --arch aarch64 --userland userland/arch/aarch64/freestanding/linux/hello.S</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>and it fails with:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>Invalid ELF image for this architecture</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>From this we can guess that the big endian metadata is actually stored in the <a href="#elf">ELF</a> file, and confirm that with:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>./run-toolchain \
+  --arch aarch64 \
+  readelf \
+  -- \
+  --file-header "$(./getvar --arch aarch64 userland_build_dir)/arch/aarch64/freestanding/linux/hello.out" \
+;</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>which contains:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>Data:                              2's complement, big endian</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>instead of the default:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>Data:                              2's complement, little endian</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>TODO does the Linux kernel support running big endian executables? I tried after building the big endian executable:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>./build-buildroot --arch aarch64
+./run --arch aarch64 --eval-after ./arch/aarch64/freestanding/linux/hello.out</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>but that failed with:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>/lkmc/arch/aarch64/freestanding/linux/hello.out: line 1: ELF@x@0@8@: not found
+/lkmc/arch/aarch64/freestanding/linux/hello.out: line 2: @@: not found
+/lkmc/arch/aarch64/freestanding/linux/hello.out: line 3: syntax error: unexpected ")"</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>TODO:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p>can you compile the Linux kernel itself as big endian? Looks like yes since there is a <a href="https://github.com/torvalds/linux/blob/v5.1/arch/arm64/Kconfig#L791"><code>config CPU_BIG_ENDIAN</code></a> See also: <a href="https://unix.stackexchange.com/questions/378829/getting-big-endian-linux-build-to-boot-on-arm-with-u-boot" class="bare">https://unix.stackexchange.com/questions/378829/getting-big-endian-linux-build-to-boot-on-arm-with-u-boot</a></p>
+</li>
+<li>
+<p>how can be is the endianess be checked and modified in the CPU?</p>
+</li>
+</ul>
+</div>
+</div>
 </div>
 </div>
 <div class="sect2">
@@ -24260,16 +24463,24 @@ AArch64, see Procedure Call Standard for the ARM 64-bit Architecture.</p>
 </div>
 </div>
 <div class="sect4">
-<h5 id="arm-processor-documentation"><a class="anchor" href="#arm-processor-documentation"></a><a class="link" href="#arm-processor-documentation">23.8.2.5. ARM processor documentation</a></h5>
+<h5 id="arm-a64-instruction-set-architecture-future-architecture-technologies-in-the-a-architecture-profile-documentation"><a class="anchor" href="#arm-a64-instruction-set-architecture-future-architecture-technologies-in-the-a-architecture-profile-documentation"></a><a class="link" href="#arm-a64-instruction-set-architecture-future-architecture-technologies-in-the-a-architecture-profile-documentation">23.8.2.5. Arm A64 Instruction Set Architecture: Future Architecture Technologies in the A architecture profile Documentation</a></h5>
+<div class="paragraph">
+<p><a href="https://developer.arm.com/docs/ddi0602/b" class="bare">https://developer.arm.com/docs/ddi0602/b</a></p>
+</div>
+<div class="paragraph">
+<p>This page contains the documentation of architecture features that were publicly announced but haven&#8217;t been merged into the main spec yet.</p>
+</div>
+</div>
+<div class="sect4">
+<h5 id="arm-processor-documentation"><a class="anchor" href="#arm-processor-documentation"></a><a class="link" href="#arm-processor-documentation">23.8.2.6. ARM processor documentation</a></h5>
 <div class="paragraph">
 <p>ARM also releases documentation specific to each given processor.</p>
 </div>
 <div class="paragraph">
 <p>This adds extra details to the more portable <a href="#armarm8">ARMv8 architecture reference manual</a> ISA documentation.</p>
 </div>
-</div>
-<div class="sect4">
-<h5 id="arm-cortex15-trm"><a class="anchor" href="#arm-cortex15-trm"></a><a class="link" href="#arm-cortex15-trm">23.8.2.6. ARM Cortex-A15 MPCore Processor Technical Reference Manual r4p0</a></h5>
+<div class="sect5">
+<h6 id="arm-cortex15-trm"><a class="anchor" href="#arm-cortex15-trm"></a><a class="link" href="#arm-cortex15-trm">23.8.2.6.1. ARM Cortex-A15 MPCore Processor Technical Reference Manual r4p0</a></h6>
 <div class="paragraph">
 <p><a href="http://infocenter.arm.com/help/topic/com.arm.doc.ddi0438i/DDI0438I_cortex_a15_r4p0_trm.pdf" class="bare">http://infocenter.arm.com/help/topic/com.arm.doc.ddi0438i/DDI0438I_cortex_a15_r4p0_trm.pdf</a></p>
 </div>
@@ -24281,8 +24492,23 @@ AArch64, see Procedure Call Standard for the ARM 64-bit Architecture.</p>
 </div>
 </div>
 </div>
+</div>
 <div class="sect1">
-<h2 id="ieee-754"><a class="anchor" href="#ieee-754"></a><a class="link" href="#ieee-754">24. IEEE 754</a></h2>
+<h2 id="elf"><a class="anchor" href="#elf"></a><a class="link" href="#elf">24. ELF</a></h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p><a href="https://en.wikipedia.org/wiki/Executable_and_Linkable_Format" class="bare">https://en.wikipedia.org/wiki/Executable_and_Linkable_Format</a></p>
+</div>
+<div class="paragraph">
+<p>This is the main format for executables, object files (<code>.o</code>) and shared libraries (<code>.so</code>) in Linux.</p>
+</div>
+<div class="paragraph">
+<p>An introduction to the format can be found at: <a href="https://cirosantilli.com/elf-hello-world" class="bare">https://cirosantilli.com/elf-hello-world</a></p>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="ieee-754"><a class="anchor" href="#ieee-754"></a><a class="link" href="#ieee-754">25. IEEE 754</a></h2>
 <div class="sectionbody">
 <div class="paragraph">
 <p><a href="https://en.wikipedia.org/wiki/IEEE_754" class="bare">https://en.wikipedia.org/wiki/IEEE_754</a></p>
@@ -24312,13 +24538,13 @@ AArch64, see Procedure Call Standard for the ARM 64-bit Architecture.</p>
 </div>
 </div>
 <div class="sect1">
-<h2 id="baremetal"><a class="anchor" href="#baremetal"></a><a class="link" href="#baremetal">25. Baremetal</a></h2>
+<h2 id="baremetal"><a class="anchor" href="#baremetal"></a><a class="link" href="#baremetal">26. Baremetal</a></h2>
 <div class="sectionbody">
 <div class="paragraph">
 <p>Getting started at: <a href="#baremetal-setup">Baremetal setup</a></p>
 </div>
 <div class="sect2">
-<h3 id="baremetal-gdb-step-debug"><a class="anchor" href="#baremetal-gdb-step-debug"></a><a class="link" href="#baremetal-gdb-step-debug">25.1. Baremetal GDB step debug</a></h3>
+<h3 id="baremetal-gdb-step-debug"><a class="anchor" href="#baremetal-gdb-step-debug"></a><a class="link" href="#baremetal-gdb-step-debug">26.1. Baremetal GDB step debug</a></h3>
 <div class="paragraph">
 <p>GDB step debug works on baremetal exactly as it does on the Linux kernel: <a href="#gdb">GDB step debug</a>.</p>
 </div>
@@ -24383,7 +24609,7 @@ AArch64, see Procedure Call Standard for the ARM 64-bit Architecture.</p>
 </div>
 </div>
 <div class="sect2">
-<h3 id="baremetal-bootloaders"><a class="anchor" href="#baremetal-bootloaders"></a><a class="link" href="#baremetal-bootloaders">25.2. Baremetal bootloaders</a></h3>
+<h3 id="baremetal-bootloaders"><a class="anchor" href="#baremetal-bootloaders"></a><a class="link" href="#baremetal-bootloaders">26.2. Baremetal bootloaders</a></h3>
 <div class="paragraph">
 <p>As can be seen from <a href="#baremetal-gdb-step-debug">Baremetal GDB step debug</a>, all examples under <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/baremetal/">baremetal/</a>, with the exception of <code>baremetal/arch/&lt;arch&gt;/no_bootloader</code>, start from our tiny bootloaders:</p>
 </div>
@@ -24447,7 +24673,7 @@ AArch64, see Procedure Call Standard for the ARM 64-bit Architecture.</p>
 </div>
 </div>
 <div class="sect2">
-<h3 id="semihosting"><a class="anchor" href="#semihosting"></a><a class="link" href="#semihosting">25.3. Semihosting</a></h3>
+<h3 id="semihosting"><a class="anchor" href="#semihosting"></a><a class="link" href="#semihosting">26.3. Semihosting</a></h3>
 <div class="paragraph">
 <p>Semihosting is a publicly documented interface specified by ARM Holdings that allows us to do some magic operations very useful in development.</p>
 </div>
@@ -24549,7 +24775,7 @@ svc 0x00123456</pre>
 </ul>
 </div>
 <div class="sect3">
-<h4 id="gem5-semihosting"><a class="anchor" href="#gem5-semihosting"></a><a class="link" href="#gem5-semihosting">25.3.1. gem5 semihosting</a></h4>
+<h4 id="gem5-semihosting"><a class="anchor" href="#gem5-semihosting"></a><a class="link" href="#gem5-semihosting">26.3.1. gem5 semihosting</a></h4>
 <div class="paragraph">
 <p>For gem5, you need:</p>
 </div>
@@ -24564,7 +24790,7 @@ svc 0x00123456</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="gem5-baremetal-carriage-return"><a class="anchor" href="#gem5-baremetal-carriage-return"></a><a class="link" href="#gem5-baremetal-carriage-return">25.4. gem5 baremetal carriage return</a></h3>
+<h3 id="gem5-baremetal-carriage-return"><a class="anchor" href="#gem5-baremetal-carriage-return"></a><a class="link" href="#gem5-baremetal-carriage-return">26.4. gem5 baremetal carriage return</a></h3>
 <div class="paragraph">
 <p>TODO: our example is printing newlines without automatic carriage return <code>\r</code> as in:</p>
 </div>
@@ -24587,7 +24813,7 @@ svc 0x00123456</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="baremetal-host-packaged-toolchain"><a class="anchor" href="#baremetal-host-packaged-toolchain"></a><a class="link" href="#baremetal-host-packaged-toolchain">25.5. Baremetal host packaged toolchain</a></h3>
+<h3 id="baremetal-host-packaged-toolchain"><a class="anchor" href="#baremetal-host-packaged-toolchain"></a><a class="link" href="#baremetal-host-packaged-toolchain">26.5. Baremetal host packaged toolchain</a></h3>
 <div class="paragraph">
 <p>For <code>arm</code>, some baremetal examples compile fine with:</p>
 </div>
@@ -24623,7 +24849,7 @@ collect2: error: ld returned 1 exit status</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="baremetal-cpp"><a class="anchor" href="#baremetal-cpp"></a><a class="link" href="#baremetal-cpp">25.6. Baremetal C++</a></h3>
+<h3 id="baremetal-cpp"><a class="anchor" href="#baremetal-cpp"></a><a class="link" href="#baremetal-cpp">26.6. Baremetal C++</a></h3>
 <div class="paragraph">
 <p>TODO not working as of 8825222579767f2ee7e46ffd8204b9e509440759 + 1. Not yet properly researched / reported upstream yet.</p>
 </div>
@@ -24683,7 +24909,7 @@ collect2: error: ld returned 1 exit status</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="gdb-builtin-cpu-simulator"><a class="anchor" href="#gdb-builtin-cpu-simulator"></a><a class="link" href="#gdb-builtin-cpu-simulator">25.7. GDB builtin CPU simulator</a></h3>
+<h3 id="gdb-builtin-cpu-simulator"><a class="anchor" href="#gdb-builtin-cpu-simulator"></a><a class="link" href="#gdb-builtin-cpu-simulator">26.7. GDB builtin CPU simulator</a></h3>
 <div class="paragraph">
 <p>It is incredible, but GDB also has a CPU simulator inside of it as documented at: <a href="https://sourceware.org/gdb/onlinedocs/gdb/Target-Commands.html" class="bare">https://sourceware.org/gdb/onlinedocs/gdb/Target-Commands.html</a></p>
 </div>
@@ -24743,7 +24969,7 @@ starti</pre>
 </ul>
 </div>
 <div class="sect3">
-<h4 id="gdb-builtin-cpu-simulator-userland"><a class="anchor" href="#gdb-builtin-cpu-simulator-userland"></a><a class="link" href="#gdb-builtin-cpu-simulator-userland">25.7.1. GDB builtin CPU simulator userland</a></h4>
+<h4 id="gdb-builtin-cpu-simulator-userland"><a class="anchor" href="#gdb-builtin-cpu-simulator-userland"></a><a class="link" href="#gdb-builtin-cpu-simulator-userland">26.7.1. GDB builtin CPU simulator userland</a></h4>
 <div class="paragraph">
 <p>Since I had this compiled, I also decided to try it out on userland.</p>
 </div>
@@ -24778,7 +25004,7 @@ starti</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="arm-baremetal"><a class="anchor" href="#arm-baremetal"></a><a class="link" href="#arm-baremetal">25.8. ARM baremetal</a></h3>
+<h3 id="arm-baremetal"><a class="anchor" href="#arm-baremetal"></a><a class="link" href="#arm-baremetal">26.8. ARM baremetal</a></h3>
 <div class="paragraph">
 <p>In this section we will focus on learning ARM architecture concepts that can only learnt on baremetal setups.</p>
 </div>
@@ -24786,7 +25012,7 @@ starti</pre>
 <p>Userland information can be found at: <a href="https://github.com/cirosantilli/arm-assembly-cheat" class="bare">https://github.com/cirosantilli/arm-assembly-cheat</a></p>
 </div>
 <div class="sect3">
-<h4 id="arm-exception-levels"><a class="anchor" href="#arm-exception-levels"></a><a class="link" href="#arm-exception-levels">25.8.1. ARM exception levels</a></h4>
+<h4 id="arm-exception-levels"><a class="anchor" href="#arm-exception-levels"></a><a class="link" href="#arm-exception-levels">26.8.1. ARM exception levels</a></h4>
 <div class="paragraph">
 <p>ARM exception levels are analogous to x86 <a href="#ring0">rings</a>.</p>
 </div>
@@ -24916,7 +25142,7 @@ CurrentEL.EL 0x3</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="arm-svc-instruction"><a class="anchor" href="#arm-svc-instruction"></a><a class="link" href="#arm-svc-instruction">25.8.2. ARM SVC instruction</a></h4>
+<h4 id="arm-svc-instruction"><a class="anchor" href="#arm-svc-instruction"></a><a class="link" href="#arm-svc-instruction">26.8.2. ARM SVC instruction</a></h4>
 <div class="paragraph">
 <p>This is the most basic example of exception handling we have.</p>
 </div>
@@ -24947,26 +25173,29 @@ CurrentEL.EL 0x3</pre>
 </div>
 <div class="literalblock">
 <div class="content">
-<pre>daif 0x3c0
-spsel 0x1
-vbar_el1 0x40000800
+<pre>DAIF 0x3C0
+SPSEL 0x1
+VBAR_EL1 0x40000800
+after_svc 0x4000209c
 lkmc_vector_trap_handler
 exc_type 0x11
 exc_type is LKMC_VECTOR_SYNC_SPX
-ESR 0x56000042
-SP 0x4200bba8
-ELR 0x40002470
-SPSR 0x600003c5
+ESR 0x5600ABCD
+ESR.EC 0x15
+ESR.EC.ISS.imm16 0xABCD
+SP 0x4200C510
+ELR 0x4000209C
+SPSR 0x600003C5
 x0 0x0
 x1 0x1
-x2 0x14
-x3 0x14
-x4 0x40008390
-x5 0xfffffff8
-x6 0x4200ba28
-x7 0x0
-x8 0x0
-x9 0x13
+x2 0x15
+x3 0x15
+x4 0x4000A178
+x5 0xFFFFFFF6
+x6 0x4200C390
+x7 0x78
+x8 0x1
+x9 0x14
 x10 0x0
 x11 0x0
 x12 0x0
@@ -24986,12 +25215,45 @@ x25 0x0
 x26 0x0
 x27 0x0
 x28 0x0
-x29 0x4200bba8
-x30 0x4000246c</pre>
+x29 0x4200C510
+x30 0x40002064</pre>
 </div>
 </div>
 <div class="paragraph">
-<p>Both QEMU and gem5 are able to trace interrupts in addition to instructions, and it is instructive to enable both and have a look at the traces:</p>
+<p>The C code does an:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>svc 0xABCD</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>and the value 0xABCD appears at the bottom of <a href="#arm-esr-register">ARM ESR register</a>:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>ESR 0x5600ABCD
+ESR.EC 0x15
+ESR.EC.ISS.imm16 0xABCD</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>The other important register is the <a href="#arm-elr-register">ARM ELR register</a>, which contains the return address after the exception.</p>
+</div>
+<div class="paragraph">
+<p>From the output, we can see that it matches the value as obtained by taking the address of a label placed just after the SVC:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>after_svc 0x4000209c
+ELR 0x4000209C</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Both QEMU and gem5 are able to trace interrupts in addition to instructions, and it is instructive to enable both and have a look at the traces.</p>
+</div>
+<div class="paragraph">
+<p>With <a href="#qemu-d-tracing">QEMU -d tracing</a>:</p>
 </div>
 <div class="literalblock">
 <div class="content">
@@ -25003,7 +25265,7 @@ x30 0x4000246c</pre>
 </div>
 </div>
 <div class="paragraph">
-<p>contains:</p>
+<p>the output contains:</p>
 </div>
 <div class="literalblock">
 <div class="content">
@@ -25022,7 +25284,7 @@ IN:
 </div>
 </div>
 <div class="paragraph">
-<p>and:</p>
+<p>And with <a href="#gem5-tracing">gem5 tracing</a>:</p>
 </div>
 <div class="literalblock">
 <div class="content">
@@ -25035,7 +25297,7 @@ IN:
 </div>
 </div>
 <div class="paragraph">
-<p>contains:</p>
+<p>the output contains:</p>
 </div>
 <div class="literalblock">
 <div class="content">
@@ -25139,19 +25401,37 @@ IN:
 <p><a href="https://github.com/NienfengYao/armv8-bare-metal/blob/572c6f95880e70aa92fe9fed4b8ad7697082a764/vector.S#L168" class="bare">https://github.com/NienfengYao/armv8-bare-metal/blob/572c6f95880e70aa92fe9fed4b8ad7697082a764/vector.S#L168</a></p>
 </li>
 <li>
-<p><a href="https://stackoverflow.com/questions/51094092/how-to-make-timer-irq-work-on-qemu-machine-virt-cpu-cortex-a57" class="bare">https://stackoverflow.com/questions/51094092/how-to-make-timer-irq-work-on-qemu-machine-virt-cpu-cortex-a57</a></p>
+<p><a href="https://stackoverflow.com/questions/24162109/arm-assembly-code-and-svc-numbering/57064062#57064062" class="bare">https://stackoverflow.com/questions/24162109/arm-assembly-code-and-svc-numbering/57064062#57064062</a></p>
 </li>
 <li>
 <p><a href="https://stackoverflow.com/questions/44991264/armv8-exception-vectors-and-handling" class="bare">https://stackoverflow.com/questions/44991264/armv8-exception-vectors-and-handling</a></p>
 </li>
-<li>
-<p><a href="https://stackoverflow.com/questions/44198483/arm-timers-and-interrupts" class="bare">https://stackoverflow.com/questions/44198483/arm-timers-and-interrupts</a></p>
-</li>
 </ul>
 </div>
+<div class="sect4">
+<h5 id="arm-esr-register"><a class="anchor" href="#arm-esr-register"></a><a class="link" href="#arm-esr-register">26.8.2.1. ARM ESR register</a></h5>
+<div class="paragraph">
+<p>Exception Syndrome Register.</p>
+</div>
+<div class="paragraph">
+<p>See example at: <a href="#arm-svc-instruction">ARM SVC instruction</a></p>
+</div>
+<div class="paragraph">
+<p>Documentation: <a href="#armarm8-db">ARMv8 architecture reference manual db</a> D12.2.36 "ESR_EL1, Exception Syndrome Register (EL1)".</p>
+</div>
+</div>
+<div class="sect4">
+<h5 id="arm-elr-register"><a class="anchor" href="#arm-elr-register"></a><a class="link" href="#arm-elr-register">26.8.2.2. ARM ELR register</a></h5>
+<div class="paragraph">
+<p>Exception Link Register.</p>
+</div>
+<div class="paragraph">
+<p>See example at: <a href="#arm-svc-instruction">ARM SVC instruction</a></p>
+</div>
+</div>
 </div>
 <div class="sect3">
-<h4 id="arm-multicore"><a class="anchor" href="#arm-multicore"></a><a class="link" href="#arm-multicore">25.8.3. ARM multicore</a></h4>
+<h4 id="arm-multicore"><a class="anchor" href="#arm-multicore"></a><a class="link" href="#arm-multicore">26.8.3. ARM multicore</a></h4>
 <div class="literalblock">
 <div class="content">
 <pre>./run --arch aarch64 --baremetal baremetal/arch/aarch64/multicore.S --cpus 2
@@ -25224,7 +25504,7 @@ IN:
 <p>Bibliography: <a href="https://stackoverflow.com/questions/980999/what-does-multicore-assembly-language-look-like/33651438#33651438" class="bare">https://stackoverflow.com/questions/980999/what-does-multicore-assembly-language-look-like/33651438#33651438</a></p>
 </div>
 <div class="sect4">
-<h5 id="arm-wfe-and-sev-instructions"><a class="anchor" href="#arm-wfe-and-sev-instructions"></a><a class="link" href="#arm-wfe-and-sev-instructions">25.8.3.1. ARM WFE and SEV instructions</a></h5>
+<h5 id="arm-wfe-and-sev-instructions"><a class="anchor" href="#arm-wfe-and-sev-instructions"></a><a class="link" href="#arm-wfe-and-sev-instructions">26.8.3.1. ARM WFE and SEV instructions</a></h5>
 <div class="paragraph">
 <p>The WFE and SEV instructions are just hints: a compliant implementation can treat them as NOPs.</p>
 </div>
@@ -25298,7 +25578,7 @@ IN:
 </div>
 </div>
 <div class="sect4">
-<h5 id="arm-psci"><a class="anchor" href="#arm-psci"></a><a class="link" href="#arm-psci">25.8.3.2. ARM PSCI</a></h5>
+<h5 id="arm-psci"><a class="anchor" href="#arm-psci"></a><a class="link" href="#arm-psci">26.8.3.2. ARM PSCI</a></h5>
 <div class="paragraph">
 <p>In QEMU, CPU 1 starts in a halted state. This can be observed from GDB, where:</p>
 </div>
@@ -25348,14 +25628,14 @@ IN:
 </div>
 </div>
 <div class="sect4">
-<h5 id="arm-dmb-instruction"><a class="anchor" href="#arm-dmb-instruction"></a><a class="link" href="#arm-dmb-instruction">25.8.3.3. ARM DMB instruction</a></h5>
+<h5 id="arm-dmb-instruction"><a class="anchor" href="#arm-dmb-instruction"></a><a class="link" href="#arm-dmb-instruction">26.8.3.3. ARM DMB instruction</a></h5>
 <div class="paragraph">
 <p>TODO: create and study a minimal examples in gem5 where the DMB instruction leads to less cycles: <a href="https://stackoverflow.com/questions/15491751/real-life-use-cases-of-barriers-dsb-dmb-isb-in-arm" class="bare">https://stackoverflow.com/questions/15491751/real-life-use-cases-of-barriers-dsb-dmb-isb-in-arm</a></p>
 </div>
 </div>
 </div>
 <div class="sect3">
-<h4 id="arm-timer"><a class="anchor" href="#arm-timer"></a><a class="link" href="#arm-timer">25.8.4. ARM timer</a></h4>
+<h4 id="arm-timer"><a class="anchor" href="#arm-timer"></a><a class="link" href="#arm-timer">26.8.4. ARM timer</a></h4>
 <div class="paragraph">
 <p>TODO get working. Attempt at: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/baremetal/arch/aarch64/timer.c">baremetal/arch/aarch64/timer.c</a></p>
 </div>
@@ -25381,9 +25661,52 @@ IN:
 </li>
 </ul>
 </div>
+<div class="paragraph">
+<p>Bibliography:</p>
+</div>
+<div class="ulist">
+<ul>
+<li>
+<p><a href="https://stackoverflow.com/questions/51094092/how-to-make-timer-irq-work-on-qemu-machine-virt-cpu-cortex-a57" class="bare">https://stackoverflow.com/questions/51094092/how-to-make-timer-irq-work-on-qemu-machine-virt-cpu-cortex-a57</a></p>
+</li>
+<li>
+<p><a href="https://stackoverflow.com/questions/44198483/arm-timers-and-interrupts" class="bare">https://stackoverflow.com/questions/44198483/arm-timers-and-interrupts</a></p>
+</li>
+</ul>
+</div>
 </div>
 <div class="sect3">
-<h4 id="arm-baremetal-bibliography"><a class="anchor" href="#arm-baremetal-bibliography"></a><a class="link" href="#arm-baremetal-bibliography">25.8.5. ARM baremetal bibliography</a></h4>
+<h4 id="arm-paging"><a class="anchor" href="#arm-paging"></a><a class="link" href="#arm-paging">26.8.5. ARM paging</a></h4>
+<div class="paragraph">
+<p>TODO create a minimal working aarch64 example analogous to the x86 one at: <a href="https://github.com/cirosantilli/x86-bare-metal-examples/blob/6dc9a73830fc05358d8d66128f740ef9906f7677/paging.S" class="bare">https://github.com/cirosantilli/x86-bare-metal-examples/blob/6dc9a73830fc05358d8d66128f740ef9906f7677/paging.S</a></p>
+</div>
+<div class="paragraph">
+<p>A general introduction to paging with x86 examples can be found at: <a href="https://cirosantilli.com/x86-paging" class="bare">https://cirosantilli.com/x86-paging</a>.</p>
+</div>
+<div class="paragraph">
+<p>ARM paging is documented at <a href="#armarm8-db">ARMv8 architecture reference manual db</a> Chapter D5 and is mostly called VMSAv8 in the ARMv8 manual (Virtual Memory System Architecture).</p>
+</div>
+<div class="paragraph">
+<p>Paging is enabled by the <code>SCTLR_EL1.M</code> bit.</p>
+</div>
+<div class="paragraph">
+<p>The base table address is selected by the register documented at <a href="#armarm8-db">ARMv8 architecture reference manual db</a> D12.2.111 "TTBR0_EL1, Translation Table Base Register 0 (EL1)".</p>
+</div>
+<div class="paragraph">
+<p>There is also a <code>TTBR1_EL1</code> register, which is for the second translation stage to speed up virtualization: <a href="https://en.wikipedia.org/wiki/Second_Level_Address_Translation" class="bare">https://en.wikipedia.org/wiki/Second_Level_Address_Translation</a> and will not be used in this section.</p>
+</div>
+<div class="paragraph">
+<p>The translation types are described at: <a href="#armarm8-db">ARMv8 architecture reference manual db</a> D5.2.4 "Memory translation granule size".</p>
+</div>
+<div class="paragraph">
+<p>From this we can see that the translation scheme uses up to 4 levels (0 to 3) and has possible granule sizes 4KiB, 16KiB and 64KiB.</p>
+</div>
+<div class="paragraph">
+<p>Page table formats are described at <a href="#armarm8-db">ARMv8 architecture reference manual db</a> D5.3.1 "VMSAv8-64 translation table level 0, level 1, and level 2 descriptor formats".</p>
+</div>
+</div>
+<div class="sect3">
+<h4 id="arm-baremetal-bibliography"><a class="anchor" href="#arm-baremetal-bibliography"></a><a class="link" href="#arm-baremetal-bibliography">26.8.6. ARM baremetal bibliography</a></h4>
 <div class="paragraph">
 <p>First, also consider the userland bibliography: <a href="#arm-assembly-bibliography">ARM assembly bibliography</a>.</p>
 </div>
@@ -25410,7 +25733,7 @@ IN:
 </ul>
 </div>
 <div class="sect4">
-<h5 id="nienfengyaoarmv8-bare-metal"><a class="anchor" href="#nienfengyaoarmv8-bare-metal"></a><a class="link" href="#nienfengyaoarmv8-bare-metal">25.8.5.1. NienfengYao/armv8-bare-metal</a></h5>
+<h5 id="nienfengyaoarmv8-bare-metal"><a class="anchor" href="#nienfengyaoarmv8-bare-metal"></a><a class="link" href="#nienfengyaoarmv8-bare-metal">26.8.6.1. NienfengYao/armv8-bare-metal</a></h5>
 <div class="paragraph">
 <p><a href="https://github.com/NienfengYao/armv8-bare-metal" class="bare">https://github.com/NienfengYao/armv8-bare-metal</a></p>
 </div>
@@ -25469,7 +25792,7 @@ IN:
 </div>
 </div>
 <div class="sect4">
-<h5 id="tukl-msdgem5-bare-metal"><a class="anchor" href="#tukl-msdgem5-bare-metal"></a><a class="link" href="#tukl-msdgem5-bare-metal">25.8.5.2. tukl-msd/gem5.bare-metal</a></h5>
+<h5 id="tukl-msdgem5-bare-metal"><a class="anchor" href="#tukl-msdgem5-bare-metal"></a><a class="link" href="#tukl-msdgem5-bare-metal">26.8.6.2. tukl-msd/gem5.bare-metal</a></h5>
 <div class="paragraph">
 <p><a href="https://github.com/tukl-msd/gem5.bare-metal" class="bare">https://github.com/tukl-msd/gem5.bare-metal</a></p>
 </div>
@@ -25511,7 +25834,7 @@ make CROSS_COMPILE_DIR=/usr/bin
 </div>
 </div>
 <div class="sect2">
-<h3 id="how-we-got-some-baremetal-stuff-to-work"><a class="anchor" href="#how-we-got-some-baremetal-stuff-to-work"></a><a class="link" href="#how-we-got-some-baremetal-stuff-to-work">25.9. How we got some baremetal stuff to work</a></h3>
+<h3 id="how-we-got-some-baremetal-stuff-to-work"><a class="anchor" href="#how-we-got-some-baremetal-stuff-to-work"></a><a class="link" href="#how-we-got-some-baremetal-stuff-to-work">26.9. How we got some baremetal stuff to work</a></h3>
 <div class="paragraph">
 <p>It is nice when thing just work.</p>
 </div>
@@ -25519,7 +25842,7 @@ make CROSS_COMPILE_DIR=/usr/bin
 <p>But you can also learn a thing or two from how I actually made them work in the first place.</p>
 </div>
 <div class="sect3">
-<h4 id="find-the-uart-address"><a class="anchor" href="#find-the-uart-address"></a><a class="link" href="#find-the-uart-address">25.9.1. Find the UART address</a></h4>
+<h4 id="find-the-uart-address"><a class="anchor" href="#find-the-uart-address"></a><a class="link" href="#find-the-uart-address">26.9.1. Find the UART address</a></h4>
 <div class="paragraph">
 <p>Enter the QEMU console:</p>
 </div>
@@ -25555,7 +25878,7 @@ make CROSS_COMPILE_DIR=/usr/bin
 </div>
 </div>
 <div class="sect3">
-<h4 id="aarch64-baremetal-neon-setup"><a class="anchor" href="#aarch64-baremetal-neon-setup"></a><a class="link" href="#aarch64-baremetal-neon-setup">25.9.2. aarch64 baremetal NEON setup</a></h4>
+<h4 id="aarch64-baremetal-neon-setup"><a class="anchor" href="#aarch64-baremetal-neon-setup"></a><a class="link" href="#aarch64-baremetal-neon-setup">26.9.2. aarch64 baremetal NEON setup</a></h4>
 <div class="paragraph">
 <p>Inside <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/baremetal/lib/aarch64.S">baremetal/lib/aarch64.S</a> there is a chunk of code that enables floating point operations:</p>
 </div>
@@ -25676,7 +25999,7 @@ ISB</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="baremetal-tests"><a class="anchor" href="#baremetal-tests"></a><a class="link" href="#baremetal-tests">25.10. Baremetal tests</a></h3>
+<h3 id="baremetal-tests"><a class="anchor" href="#baremetal-tests"></a><a class="link" href="#baremetal-tests">26.10. Baremetal tests</a></h3>
 <div class="paragraph">
 <p>Baremetal tests work exactly like <a href="#user-mode-tests">User mode tests</a>, except that you have to add the <code>--mode baremetal</code> option, for example:</p>
 </div>
@@ -25695,7 +26018,7 @@ ISB</pre>
 </div>
 </div>
 <div class="sect1">
-<h2 id="android"><a class="anchor" href="#android"></a><a class="link" href="#android">26. Android</a></h2>
+<h2 id="android"><a class="anchor" href="#android"></a><a class="link" href="#android">27. Android</a></h2>
 <div class="sectionbody">
 <div class="paragraph">
 <p>Remember: Android AOSP is a huge undocumented piece of bloatware. It&#8217;s integration into this repo will likely never be super good.</p>
@@ -25743,7 +26066,7 @@ ISB</pre>
 <p>Tested on: <code>8.1.0_r60</code>.</p>
 </div>
 <div class="sect2">
-<h3 id="android-image-structure"><a class="anchor" href="#android-image-structure"></a><a class="link" href="#android-image-structure">26.1. Android image structure</a></h3>
+<h3 id="android-image-structure"><a class="anchor" href="#android-image-structure"></a><a class="link" href="#android-image-structure">27.1. Android image structure</a></h3>
 <div class="paragraph">
 <p><a href="https://source.android.com/devices/bootloader/partitions-images" class="bare">https://source.android.com/devices/bootloader/partitions-images</a></p>
 </div>
@@ -25827,7 +26150,7 @@ vendor-qemu</pre>
 <p>Tested on: <code>8.1.0_r60</code>.</p>
 </div>
 <div class="sect3">
-<h4 id="android-images-read-only"><a class="anchor" href="#android-images-read-only"></a><a class="link" href="#android-images-read-only">26.1.1. Android images read-only</a></h4>
+<h4 id="android-images-read-only"><a class="anchor" href="#android-images-read-only"></a><a class="link" href="#android-images-read-only">27.1.1. Android images read-only</a></h4>
 <div class="paragraph">
 <p>From <code>mount</code>, we can see that some of the mounted images are <code>ro</code>.</p>
 </div>
@@ -25900,7 +26223,7 @@ date &gt;/system/a</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="android-data-partition"><a class="anchor" href="#android-data-partition"></a><a class="link" href="#android-data-partition">26.1.2. Android /data partition</a></h4>
+<h4 id="android-data-partition"><a class="anchor" href="#android-data-partition"></a><a class="link" href="#android-data-partition">27.1.2. Android /data partition</a></h4>
 <div class="paragraph">
 <p>When I install an app like F-Droid, it goes under <code>/data</code> according to:</p>
 </div>
@@ -25961,7 +26284,7 @@ date &gt;/system/a</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="install-android-apps"><a class="anchor" href="#install-android-apps"></a><a class="link" href="#install-android-apps">26.2. Install Android apps</a></h3>
+<h3 id="install-android-apps"><a class="anchor" href="#install-android-apps"></a><a class="link" href="#install-android-apps">27.2. Install Android apps</a></h3>
 <div class="paragraph">
 <p>I don&#8217;t know how to download files from the web on Vanilla android, the default browser does not download anything, and there is no <code>wget</code>:</p>
 </div>
@@ -26011,7 +26334,7 @@ date &gt;/system/a</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="android-init"><a class="anchor" href="#android-init"></a><a class="link" href="#android-init">26.3. Android init</a></h3>
+<h3 id="android-init"><a class="anchor" href="#android-init"></a><a class="link" href="#android-init">27.3. Android init</a></h3>
 <div class="paragraph">
 <p>For Linux in general, see: <a href="#init">init</a>.</p>
 </div>
@@ -26060,7 +26383,7 @@ import /init.${ro.zygote}.rc</pre>
 </div>
 </div>
 <div class="sect1">
-<h2 id="benchmark-this-repo"><a class="anchor" href="#benchmark-this-repo"></a><a class="link" href="#benchmark-this-repo">27. Benchmark this repo</a></h2>
+<h2 id="benchmark-this-repo"><a class="anchor" href="#benchmark-this-repo"></a><a class="link" href="#benchmark-this-repo">28. Benchmark this repo</a></h2>
 <div class="sectionbody">
 <div class="paragraph">
 <p>TODO: didn&#8217;t fully port during refactor after 3b0a343647bed577586989fb702b760bd280844a. Reimplementing should not be hard.</p>
@@ -26089,7 +26412,7 @@ cd -
 </div>
 </div>
 <div class="sect2">
-<h3 id="continuous-integraion"><a class="anchor" href="#continuous-integraion"></a><a class="link" href="#continuous-integraion">27.1. Continuous integraion</a></h3>
+<h3 id="continuous-integraion"><a class="anchor" href="#continuous-integraion"></a><a class="link" href="#continuous-integraion">28.1. Continuous integraion</a></h3>
 <div class="paragraph">
 <p>We have exploreed a few Continuous integration solutions.</p>
 </div>
@@ -26097,13 +26420,13 @@ cd -
 <p>We haven&#8217;t setup any of them yet.</p>
 </div>
 <div class="sect3">
-<h4 id="travis"><a class="anchor" href="#travis"></a><a class="link" href="#travis">27.1.1. Travis</a></h4>
+<h4 id="travis"><a class="anchor" href="#travis"></a><a class="link" href="#travis">28.1.1. Travis</a></h4>
 <div class="paragraph">
 <p>We tried to automate it on Travis with <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/.travis.yml">.travis.yml</a> but it hits the current 50 minute job timeout: <a href="https://travis-ci.org/cirosantilli/linux-kernel-module-cheat/builds/296454523" class="bare">https://travis-ci.org/cirosantilli/linux-kernel-module-cheat/builds/296454523</a> And I bet it would likely hit a disk maxout either way if it went on.</p>
 </div>
 </div>
 <div class="sect3">
-<h4 id="circleci"><a class="anchor" href="#circleci"></a><a class="link" href="#circleci">27.1.2. CircleCI</a></h4>
+<h4 id="circleci"><a class="anchor" href="#circleci"></a><a class="link" href="#circleci">28.1.2. CircleCI</a></h4>
 <div class="paragraph">
 <p>This setup sucessfully built gem5 on every commit: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/.circleci/config.yml">.circleci/config.yml</a></p>
 </div>
@@ -26132,15 +26455,15 @@ cd -
 </div>
 </div>
 <div class="sect2">
-<h3 id="benchmark-this-repo-benchmarks"><a class="anchor" href="#benchmark-this-repo-benchmarks"></a><a class="link" href="#benchmark-this-repo-benchmarks">27.2. Benchmark this repo benchmarks</a></h3>
+<h3 id="benchmark-this-repo-benchmarks"><a class="anchor" href="#benchmark-this-repo-benchmarks"></a><a class="link" href="#benchmark-this-repo-benchmarks">28.2. Benchmark this repo benchmarks</a></h3>
 <div class="sect3">
-<h4 id="benchmark-linux-kernel-boot"><a class="anchor" href="#benchmark-linux-kernel-boot"></a><a class="link" href="#benchmark-linux-kernel-boot">27.2.1. Benchmark Linux kernel boot</a></h4>
+<h4 id="benchmark-linux-kernel-boot"><a class="anchor" href="#benchmark-linux-kernel-boot"></a><a class="link" href="#benchmark-linux-kernel-boot">28.2.1. Benchmark Linux kernel boot</a></h4>
 <div class="paragraph">
 <p>Run all kernel boot benchmarks for one arch:</p>
 </div>
 <div class="literalblock">
 <div class="content">
-<pre>./build-test-boot --size 3 &amp;&amp; ./test-boot --size 3
+<pre>./build-test-boot --size 3 &amp;&amp; ./test-boot --all-archs --all-emulators --size 3
 cat "$(./getvar test_boot_benchmark_file)"</pre>
 </div>
 </div>
@@ -26219,7 +26542,7 @@ instructions 124346081</pre>
 <p>TODO: aarch64 gem5 and QEMU use the same kernel, so why is the gem5 instruction count so much much higher?</p>
 </div>
 <div class="sect4">
-<h5 id="gem5-arm-hpi-boot-takes-much-longer-than-aarch64"><a class="anchor" href="#gem5-arm-hpi-boot-takes-much-longer-than-aarch64"></a><a class="link" href="#gem5-arm-hpi-boot-takes-much-longer-than-aarch64">27.2.1.1. gem5 arm HPI boot takes much longer than aarch64</a></h5>
+<h5 id="gem5-arm-hpi-boot-takes-much-longer-than-aarch64"><a class="anchor" href="#gem5-arm-hpi-boot-takes-much-longer-than-aarch64"></a><a class="link" href="#gem5-arm-hpi-boot-takes-much-longer-than-aarch64">28.2.1.1. gem5 arm HPI boot takes much longer than aarch64</a></h5>
 <div class="paragraph">
 <p>TODO 62f6870e4e0b384c4bd2d514116247e81b241251 takes 33 minutes to finish at 62f6870e4e0b384c4bd2d514116247e81b241251:</p>
 </div>
@@ -26245,7 +26568,7 @@ instructions 124346081</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="gem5-x86_64-derivo3cpu-boot-panics"><a class="anchor" href="#gem5-x86_64-derivo3cpu-boot-panics"></a><a class="link" href="#gem5-x86_64-derivo3cpu-boot-panics">27.2.1.2. gem5 x86_64 DerivO3CPU boot panics</a></h5>
+<h5 id="gem5-x86_64-derivo3cpu-boot-panics"><a class="anchor" href="#gem5-x86_64-derivo3cpu-boot-panics"></a><a class="link" href="#gem5-x86_64-derivo3cpu-boot-panics">28.2.1.2. gem5 x86_64 DerivO3CPU boot panics</a></h5>
 <div class="paragraph">
 <p><a href="https://github.com/cirosantilli-work/gem5-issues/issues/2" class="bare">https://github.com/cirosantilli-work/gem5-issues/issues/2</a></p>
 </div>
@@ -26257,7 +26580,7 @@ instructions 124346081</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="benchmark-builds"><a class="anchor" href="#benchmark-builds"></a><a class="link" href="#benchmark-builds">27.2.2. Benchmark builds</a></h4>
+<h4 id="benchmark-builds"><a class="anchor" href="#benchmark-builds"></a><a class="link" href="#benchmark-builds">28.2.2. Benchmark builds</a></h4>
 <div class="paragraph">
 <p>The build times are calculated after doing <code>./configure</code> and <a href="https://buildroot.org/downloads/manual/manual.html#_offline_builds"><code>make source</code></a>, which downloads the sources, and basically benchmarks the <a href="#benchmark-internets">Internet</a>.</p>
 </div>
@@ -26282,7 +26605,7 @@ cat ../linux-kernel-module-cheat-regression/*/build-time.log</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="find-which-packages-are-making-the-build-slow-and-big"><a class="anchor" href="#find-which-packages-are-making-the-build-slow-and-big"></a><a class="link" href="#find-which-packages-are-making-the-build-slow-and-big">27.2.2.1. Find which packages are making the build slow and big</a></h5>
+<h5 id="find-which-packages-are-making-the-build-slow-and-big"><a class="anchor" href="#find-which-packages-are-making-the-build-slow-and-big"></a><a class="link" href="#find-which-packages-are-making-the-build-slow-and-big">28.2.2.1. Find which packages are making the build slow and big</a></h5>
 <div class="literalblock">
 <div class="content">
 <pre>./build-buildroot -- graph-build graph-size graph-depends
@@ -26293,14 +26616,14 @@ xdg-open graph-size.pdf</pre>
 </div>
 </div>
 <div class="sect5">
-<h6 id="prebuilt-toolchain"><a class="anchor" href="#prebuilt-toolchain"></a><a class="link" href="#prebuilt-toolchain">27.2.2.1.1. Buildroot use prebuilt host toolchain</a></h6>
+<h6 id="prebuilt-toolchain"><a class="anchor" href="#prebuilt-toolchain"></a><a class="link" href="#prebuilt-toolchain">28.2.2.1.1. Buildroot use prebuilt host toolchain</a></h6>
 <div class="paragraph">
 <p>The biggest build time hog is always GCC, and it does not look like we can use a precompiled one: <a href="https://stackoverflow.com/questions/10833672/buildroot-environment-with-host-toolchain" class="bare">https://stackoverflow.com/questions/10833672/buildroot-environment-with-host-toolchain</a></p>
 </div>
 </div>
 </div>
 <div class="sect4">
-<h5 id="benchmark-buildroot-build-baseline"><a class="anchor" href="#benchmark-buildroot-build-baseline"></a><a class="link" href="#benchmark-buildroot-build-baseline">27.2.2.2. Benchmark Buildroot build baseline</a></h5>
+<h5 id="benchmark-buildroot-build-baseline"><a class="anchor" href="#benchmark-buildroot-build-baseline"></a><a class="link" href="#benchmark-buildroot-build-baseline">28.2.2.2. Benchmark Buildroot build baseline</a></h5>
 <div class="paragraph">
 <p>This is the minimal build we could expect to get away with.</p>
 </div>
@@ -26368,7 +26691,7 @@ xdg-open graph-size.pdf</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="benchmark-gem5-build"><a class="anchor" href="#benchmark-gem5-build"></a><a class="link" href="#benchmark-gem5-build">27.2.2.3. Benchmark gem5 build</a></h5>
+<h5 id="benchmark-gem5-build"><a class="anchor" href="#benchmark-gem5-build"></a><a class="link" href="#benchmark-gem5-build">28.2.2.3. Benchmark gem5 build</a></h5>
 <div class="paragraph">
 <p>How long it takes to build gem5 itself.</p>
 </div>
@@ -26388,7 +26711,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect5">
-<h6 id="benchmark-gem5-single-file-change-rebuild-time"><a class="anchor" href="#benchmark-gem5-single-file-change-rebuild-time"></a><a class="link" href="#benchmark-gem5-single-file-change-rebuild-time">27.2.2.3.1. Benchmark gem5 single file change rebuild time</a></h6>
+<h6 id="benchmark-gem5-single-file-change-rebuild-time"><a class="anchor" href="#benchmark-gem5-single-file-change-rebuild-time"></a><a class="link" href="#benchmark-gem5-single-file-change-rebuild-time">28.2.2.3.1. Benchmark gem5 single file change rebuild time</a></h6>
 <div class="paragraph">
 <p>This is the critical development parameter, and is dominated by the link time of huge binaries.</p>
 </div>
@@ -26465,9 +26788,9 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="benchmark-machines"><a class="anchor" href="#benchmark-machines"></a><a class="link" href="#benchmark-machines">27.3. Benchmark machines</a></h3>
+<h3 id="benchmark-machines"><a class="anchor" href="#benchmark-machines"></a><a class="link" href="#benchmark-machines">28.3. Benchmark machines</a></h3>
 <div class="sect3">
-<h4 id="p51"><a class="anchor" href="#p51"></a><a class="link" href="#p51">27.3.1. P51</a></h4>
+<h4 id="p51"><a class="anchor" href="#p51"></a><a class="link" href="#p51">28.3.1. P51</a></h4>
 <div class="paragraph">
 <p>Lenovo ThinkPad <a href="https://www3.lenovo.com/gb/en/laptops/thinkpad/p-series/P51/p/22TP2WPWP51">P51 laptop</a>:</p>
 </div>
@@ -26496,9 +26819,9 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="benchmark-internets"><a class="anchor" href="#benchmark-internets"></a><a class="link" href="#benchmark-internets">27.4. Benchmark Internets</a></h3>
+<h3 id="benchmark-internets"><a class="anchor" href="#benchmark-internets"></a><a class="link" href="#benchmark-internets">28.4. Benchmark Internets</a></h3>
 <div class="sect3">
-<h4 id="38mbps-internet"><a class="anchor" href="#38mbps-internet"></a><a class="link" href="#38mbps-internet">27.4.1. 38Mbps internet</a></h4>
+<h4 id="38mbps-internet"><a class="anchor" href="#38mbps-internet"></a><a class="link" href="#38mbps-internet">28.4.1. 38Mbps internet</a></h4>
 <div class="paragraph">
 <p>2c12b21b304178a81c9912817b782ead0286d282:</p>
 </div>
@@ -26518,7 +26841,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="benchmark-this-repo-bibliography"><a class="anchor" href="#benchmark-this-repo-bibliography"></a><a class="link" href="#benchmark-this-repo-bibliography">27.5. Benchmark this repo bibliography</a></h3>
+<h3 id="benchmark-this-repo-bibliography"><a class="anchor" href="#benchmark-this-repo-bibliography"></a><a class="link" href="#benchmark-this-repo-bibliography">28.5. Benchmark this repo bibliography</a></h3>
 <div class="paragraph">
 <p>gem5:</p>
 </div>
@@ -26546,10 +26869,10 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect1">
-<h2 id="about-this-repo"><a class="anchor" href="#about-this-repo"></a><a class="link" href="#about-this-repo">28. About this repo</a></h2>
+<h2 id="about-this-repo"><a class="anchor" href="#about-this-repo"></a><a class="link" href="#about-this-repo">29. About this repo</a></h2>
 <div class="sectionbody">
 <div class="sect2">
-<h3 id="supported-hosts"><a class="anchor" href="#supported-hosts"></a><a class="link" href="#supported-hosts">28.1. Supported hosts</a></h3>
+<h3 id="supported-hosts"><a class="anchor" href="#supported-hosts"></a><a class="link" href="#supported-hosts">29.1. Supported hosts</a></h3>
 <div class="paragraph">
 <p>The host requirements depend a lot on which examples you want to run.</p>
 </div>
@@ -26598,9 +26921,9 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="common-build-issues"><a class="anchor" href="#common-build-issues"></a><a class="link" href="#common-build-issues">28.2. Common build issues</a></h3>
+<h3 id="common-build-issues"><a class="anchor" href="#common-build-issues"></a><a class="link" href="#common-build-issues">29.2. Common build issues</a></h3>
 <div class="sect3">
-<h4 id="put-source-uris-in-sources"><a class="anchor" href="#put-source-uris-in-sources"></a><a class="link" href="#put-source-uris-in-sources">28.2.1. You must put some 'source' URIs in your sources.list</a></h4>
+<h4 id="put-source-uris-in-sources"><a class="anchor" href="#put-source-uris-in-sources"></a><a class="link" href="#put-source-uris-in-sources">29.2.1. You must put some 'source' URIs in your sources.list</a></h4>
 <div class="paragraph">
 <p>If <code>./build --download-dependencies</code> fails with:</p>
 </div>
@@ -26614,7 +26937,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="build-from-downloaded-source-zip-files"><a class="anchor" href="#build-from-downloaded-source-zip-files"></a><a class="link" href="#build-from-downloaded-source-zip-files">28.2.2. Build from downloaded source zip files</a></h4>
+<h4 id="build-from-downloaded-source-zip-files"><a class="anchor" href="#build-from-downloaded-source-zip-files"></a><a class="link" href="#build-from-downloaded-source-zip-files">29.2.2. Build from downloaded source zip files</a></h4>
 <div class="paragraph">
 <p>It does not work if you just download the <code>.zip</code> with the sources for this repository from GitHub because we use <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/.gitmodules">Git submodules</a>, you must clone this repo.</p>
 </div>
@@ -26624,7 +26947,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="run-command-after-boot"><a class="anchor" href="#run-command-after-boot"></a><a class="link" href="#run-command-after-boot">28.3. Run command after boot</a></h3>
+<h3 id="run-command-after-boot"><a class="anchor" href="#run-command-after-boot"></a><a class="link" href="#run-command-after-boot">29.3. Run command after boot</a></h3>
 <div class="paragraph">
 <p>If you just want to run a command after boot ends without thinking much about it, just use the <code>--eval-after</code> option, e.g.:</p>
 </div>
@@ -26641,7 +26964,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="default-command-line-arguments"><a class="anchor" href="#default-command-line-arguments"></a><a class="link" href="#default-command-line-arguments">28.4. Default command line arguments</a></h3>
+<h3 id="default-command-line-arguments"><a class="anchor" href="#default-command-line-arguments"></a><a class="link" href="#default-command-line-arguments">29.4. Default command line arguments</a></h3>
 <div class="paragraph">
 <p>It gets annoying to retype <code>--arch aarch64</code> for every single command, or to remember <code>--config</code> setups.</p>
 </div>
@@ -26686,12 +27009,24 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="build-the-documentation"><a class="anchor" href="#build-the-documentation"></a><a class="link" href="#build-the-documentation">28.5. Build the documentation</a></h3>
+<h3 id="build-the-documentation"><a class="anchor" href="#build-the-documentation"></a><a class="link" href="#build-the-documentation">29.5. Build the documentation</a></h3>
 <div class="paragraph">
 <p>You don&#8217;t need to depend on GitHub.</p>
 </div>
 <div class="paragraph">
-<p>To build the first time use:</p>
+<p>For a quick and dirty build, install <a href="https://asciidoctor.org/">Asciidoctor</a> however you like and build:</p>
+</div>
+<div class="literalblock">
+<div class="content">
+<pre>asciidotor README.adoc
+xdg-open README.html</pre>
+</div>
+</div>
+<div class="paragraph">
+<p>For development, you will want to do a more controlled build with extra error checking as follows.</p>
+</div>
+<div class="paragraph">
+<p>For the initial build do:</p>
 </div>
 <div class="literalblock">
 <div class="content">
@@ -26713,7 +27048,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 <p>Source: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/build-doc">build-doc</a></p>
 </div>
 <div class="paragraph">
-<p>Then just open the HTML output at:</p>
+<p>The HTML output is located at:</p>
 </div>
 <div class="literalblock">
 <div class="content">
@@ -26721,7 +27056,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="documentation-verification"><a class="anchor" href="#documentation-verification"></a><a class="link" href="#documentation-verification">28.5.1. Documentation verification</a></h4>
+<h4 id="documentation-verification"><a class="anchor" href="#documentation-verification"></a><a class="link" href="#documentation-verification">29.5.1. Documentation verification</a></h4>
 <div class="paragraph">
 <p>When running <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/build-doc">build-doc</a>, we do the following checks:</p>
 </div>
@@ -26742,7 +27077,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 <p>The scripts prints what you have to fix and exits with an error status if there are any errors.</p>
 </div>
 <div class="sect4">
-<h5 id="asciidoctor-extract-link-targets"><a class="anchor" href="#asciidoctor-extract-link-targets"></a><a class="link" href="#asciidoctor-extract-link-targets">28.5.1.1. asciidoctor/extract-link-targets</a></h5>
+<h5 id="asciidoctor-extract-link-targets"><a class="anchor" href="#asciidoctor-extract-link-targets"></a><a class="link" href="#asciidoctor-extract-link-targets">29.5.1.1. asciidoctor/extract-link-targets</a></h5>
 <div class="paragraph">
 <p>Documentation for <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/asciidoctor/extract-link-targets">asciidoctor/extract-link-targets</a></p>
 </div>
@@ -26765,7 +27100,7 @@ tail -n+1 ../linux-kernel-module-cheat-regression/*/gem5-bench-build-*.txt</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="asciidoctor-extract-header-ids"><a class="anchor" href="#asciidoctor-extract-header-ids"></a><a class="link" href="#asciidoctor-extract-header-ids">28.5.1.2. asciidoctor/extract-header-ids</a></h5>
+<h5 id="asciidoctor-extract-header-ids"><a class="anchor" href="#asciidoctor-extract-header-ids"></a><a class="link" href="#asciidoctor-extract-header-ids">29.5.1.2. asciidoctor/extract-header-ids</a></h5>
 <div class="paragraph">
 <p>Documentation for <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/asciidoctor/extract-header-ids">asciidoctor/extract-header-ids</a></p>
 </div>
@@ -26807,7 +27142,7 @@ explicitly-given</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="asciidoctor-link-target-up-rb"><a class="anchor" href="#asciidoctor-link-target-up-rb"></a><a class="link" href="#asciidoctor-link-target-up-rb">28.6. asciidoctor/link-target-up.rb</a></h3>
+<h3 id="asciidoctor-link-target-up-rb"><a class="anchor" href="#asciidoctor-link-target-up-rb"></a><a class="link" href="#asciidoctor-link-target-up-rb">29.6. asciidoctor/link-target-up.rb</a></h3>
 <div class="paragraph">
 <p>The Asciidoctor extension scripts:</p>
 </div>
@@ -26835,7 +27170,7 @@ explicitly-given</pre>
 </ul>
 </div>
 <div class="sect3">
-<h4 id="github-pages"><a class="anchor" href="#github-pages"></a><a class="link" href="#github-pages">28.6.1. GitHub pages</a></h4>
+<h4 id="github-pages"><a class="anchor" href="#github-pages"></a><a class="link" href="#github-pages">29.6.1. GitHub pages</a></h4>
 <div class="paragraph">
 <p>As mentioned before the TOC, we have to push this README to GitHub pages due to: <a href="https://github.com/isaacs/github/issues/1610" class="bare">https://github.com/isaacs/github/issues/1610</a></p>
 </div>
@@ -26885,7 +27220,7 @@ explicitly-given</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="clean-the-build"><a class="anchor" href="#clean-the-build"></a><a class="link" href="#clean-the-build">28.7. Clean the build</a></h3>
+<h3 id="clean-the-build"><a class="anchor" href="#clean-the-build"></a><a class="link" href="#clean-the-build">29.7. Clean the build</a></h3>
 <div class="paragraph">
 <p>You did something crazy, and nothing seems to work anymore?</p>
 </div>
@@ -26949,7 +27284,7 @@ ls "$(./getvar buildroot_build_dir)"</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="ccache"><a class="anchor" href="#ccache"></a><a class="link" href="#ccache">28.8. ccache</a></h3>
+<h3 id="ccache"><a class="anchor" href="#ccache"></a><a class="link" href="#ccache">29.8. ccache</a></h3>
 <div class="paragraph">
 <p><a href="https://en.wikipedia.org/wiki/Ccache">ccache</a> <a href="#benchmark-builds">might</a> save you a lot of re-build when you decide to <a href="#clean-the-build">Clean the build</a> or create a new <a href="#build-variants">build variant</a>.</p>
 </div>
@@ -27018,7 +27353,7 @@ export CCACHE_MAXSIZE="20G"</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="rebuild-buildroot-while-running"><a class="anchor" href="#rebuild-buildroot-while-running"></a><a class="link" href="#rebuild-buildroot-while-running">28.9. Rebuild Buildroot while running</a></h3>
+<h3 id="rebuild-buildroot-while-running"><a class="anchor" href="#rebuild-buildroot-while-running"></a><a class="link" href="#rebuild-buildroot-while-running">29.9. Rebuild Buildroot while running</a></h3>
 <div class="paragraph">
 <p>It is not possible to rebuild the root filesystem while running QEMU because QEMU holds the file qcow2 file:</p>
 </div>
@@ -27029,7 +27364,7 @@ export CCACHE_MAXSIZE="20G"</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="simultaneous-runs"><a class="anchor" href="#simultaneous-runs"></a><a class="link" href="#simultaneous-runs">28.10. Simultaneous runs</a></h3>
+<h3 id="simultaneous-runs"><a class="anchor" href="#simultaneous-runs"></a><a class="link" href="#simultaneous-runs">29.10. Simultaneous runs</a></h3>
 <div class="paragraph">
 <p>When doing long simulations sweeping across multiple system parameters, it becomes fundamental to do multiple simulations in parallel.</p>
 </div>
@@ -27164,7 +27499,7 @@ less "$(./getvar --arch aarch64 --emulator gem5 --run-id 1 termout_file)"</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="build-variants"><a class="anchor" href="#build-variants"></a><a class="link" href="#build-variants">28.11. Build variants</a></h3>
+<h3 id="build-variants"><a class="anchor" href="#build-variants"></a><a class="link" href="#build-variants">29.11. Build variants</a></h3>
 <div class="paragraph">
 <p>It often happens that you are comparing two versions of the build, a good and a bad one, and trying to figure out why the bad one is bad.</p>
 </div>
@@ -27172,7 +27507,7 @@ less "$(./getvar --arch aarch64 --emulator gem5 --run-id 1 termout_file)"</pre>
 <p>Our build variants system allows you to keep multiple built versions of all major components, so that you can easily switching between running one or the other.</p>
 </div>
 <div class="sect3">
-<h4 id="linux-kernel-build-variants"><a class="anchor" href="#linux-kernel-build-variants"></a><a class="link" href="#linux-kernel-build-variants">28.11.1. Linux kernel build variants</a></h4>
+<h4 id="linux-kernel-build-variants"><a class="anchor" href="#linux-kernel-build-variants"></a><a class="link" href="#linux-kernel-build-variants">29.11.1. Linux kernel build variants</a></h4>
 <div class="paragraph">
 <p>If you want to keep two builds around, one for the latest Linux version, and the other for Linux <code>v4.16</code>:</p>
 </div>
@@ -27212,7 +27547,7 @@ git -C "$(./getvar linux_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="qemu-build-variants"><a class="anchor" href="#qemu-build-variants"></a><a class="link" href="#qemu-build-variants">28.11.2. QEMU build variants</a></h4>
+<h4 id="qemu-build-variants"><a class="anchor" href="#qemu-build-variants"></a><a class="link" href="#qemu-build-variants">29.11.2. QEMU build variants</a></h4>
 <div class="paragraph">
 <p>Analogous to the <a href="#linux-kernel-build-variants">Linux kernel build variants</a> but with the <code>--qemu-build-id</code> option instead:</p>
 </div>
@@ -27228,7 +27563,7 @@ git -C "$(./getvar qemu_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="gem5-build-variants"><a class="anchor" href="#gem5-build-variants"></a><a class="link" href="#gem5-build-variants">28.11.3. gem5 build variants</a></h4>
+<h4 id="gem5-build-variants"><a class="anchor" href="#gem5-build-variants"></a><a class="link" href="#gem5-build-variants">29.11.3. gem5 build variants</a></h4>
 <div class="paragraph">
 <p>Analogous to the <a href="#linux-kernel-build-variants">Linux kernel build variants</a> but with the <code>--gem5-build-id</code> option instead:</p>
 </div>
@@ -27259,7 +27594,7 @@ git -C "$(./getvar gem5_source_dir)" checkout some-branch
 <p>Therefore, you can&#8217;t forget to checkout to the sources to that of the corresponding build before running, unless you explicitly tell gem5 to use a non-default source tree with <a href="#gem5-worktree">gem5 worktree</a>. This becomes inevitable when you want to launch multiple simultaneous runs at different checkouts.</p>
 </div>
 <div class="sect4">
-<h5 id="gem5-worktree"><a class="anchor" href="#gem5-worktree"></a><a class="link" href="#gem5-worktree">28.11.3.1. gem5 worktree</a></h5>
+<h5 id="gem5-worktree"><a class="anchor" href="#gem5-worktree"></a><a class="link" href="#gem5-worktree">29.11.3.1. gem5 worktree</a></h5>
 <div class="paragraph">
 <p><a href="#gem5-build-variants"><code>--gem5-build-id</code></a> goes a long way, but if you want to seamlessly switch between two gem5 tress without checking out multiple times, then <code>--gem5-worktree</code> is for you.</p>
 </div>
@@ -27312,7 +27647,7 @@ cd -
 </div>
 </div>
 <div class="sect4">
-<h5 id="gem5-private-source-trees"><a class="anchor" href="#gem5-private-source-trees"></a><a class="link" href="#gem5-private-source-trees">28.11.3.2. gem5 private source trees</a></h5>
+<h5 id="gem5-private-source-trees"><a class="anchor" href="#gem5-private-source-trees"></a><a class="link" href="#gem5-private-source-trees">29.11.3.2. gem5 private source trees</a></h5>
 <div class="paragraph">
 <p>Suppose that you are working on a private fork of gem5, but you want to use this repository to develop it as well.</p>
 </div>
@@ -27355,7 +27690,7 @@ gem5_internal="$(pwd)/gem5-internal"</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="gem5-debug-build"><a class="anchor" href="#gem5-debug-build"></a><a class="link" href="#gem5-debug-build">28.11.3.3. gem5 debug build</a></h5>
+<h5 id="gem5-debug-build"><a class="anchor" href="#gem5-debug-build"></a><a class="link" href="#gem5-debug-build">29.11.3.3. gem5 debug build</a></h5>
 <div class="paragraph">
 <p>The <code>gem5.debug</code> executable has optimizations turned off unlike the default <code>gem5.opt</code>, and provides a much better <a href="#debug-the-emulator">debug experience</a>:</p>
 </div>
@@ -27386,7 +27721,7 @@ gem5_internal="$(pwd)/gem5-internal"</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="buildroot-build-variants"><a class="anchor" href="#buildroot-build-variants"></a><a class="link" href="#buildroot-build-variants">28.11.4. Buildroot build variants</a></h4>
+<h4 id="buildroot-build-variants"><a class="anchor" href="#buildroot-build-variants"></a><a class="link" href="#buildroot-build-variants">29.11.4. Buildroot build variants</a></h4>
 <div class="paragraph">
 <p>Allows you to have multiple versions of the GCC toolchain or root filesystem.</p>
 </div>
@@ -27406,9 +27741,9 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect2">
-<h3 id="directory-structure"><a class="anchor" href="#directory-structure"></a><a class="link" href="#directory-structure">28.12. Directory structure</a></h3>
+<h3 id="directory-structure"><a class="anchor" href="#directory-structure"></a><a class="link" href="#directory-structure">29.12. Directory structure</a></h3>
 <div class="sect3">
-<h4 id="lkmc-directory"><a class="anchor" href="#lkmc-directory"></a><a class="link" href="#lkmc-directory">28.12.1. lkmc directory</a></h4>
+<h4 id="lkmc-directory"><a class="anchor" href="#lkmc-directory"></a><a class="link" href="#lkmc-directory">29.12.1. lkmc directory</a></h4>
 <div class="paragraph">
 <p><a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/lkmc/">lkmc/</a> contains sources and headers that are shared across kernel modules, userland and baremetal examples.</p>
 </div>
@@ -27419,7 +27754,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 <p>Another option would have been to name it as <code>includes/lkmc</code>, but that would make paths longer, and we might want to store source code in that directory as well in the future.</p>
 </div>
 <div class="sect4">
-<h5 id="userland-objects-vs-header-only"><a class="anchor" href="#userland-objects-vs-header-only"></a><a class="link" href="#userland-objects-vs-header-only">28.12.1.1. Userland objects vs header-only</a></h5>
+<h5 id="userland-objects-vs-header-only"><a class="anchor" href="#userland-objects-vs-header-only"></a><a class="link" href="#userland-objects-vs-header-only">29.12.1.1. Userland objects vs header-only</a></h5>
 <div class="paragraph">
 <p>When factoring out functionality across userland examples, there are two main options:</p>
 </div>
@@ -27478,7 +27813,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="buildroot_packages-directory"><a class="anchor" href="#buildroot_packages-directory"></a><a class="link" href="#buildroot_packages-directory">28.12.2. buildroot_packages directory</a></h4>
+<h4 id="buildroot_packages-directory"><a class="anchor" href="#buildroot_packages-directory"></a><a class="link" href="#buildroot_packages-directory">29.12.2. buildroot_packages directory</a></h4>
 <div class="paragraph">
 <p>Source: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/buildroot_packages/">buildroot_packages/</a></p>
 </div>
@@ -27527,7 +27862,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 <p>A custom build script can give you more flexibility: e.g. the package can be made work with other root filesystems more easily, have better <a href="#9p">9P</a> support, and rebuild faster as it evades some Buildroot boilerplate.</p>
 </div>
 <div class="sect4">
-<h5 id="kernel_modules-buildroot-package"><a class="anchor" href="#kernel_modules-buildroot-package"></a><a class="link" href="#kernel_modules-buildroot-package">28.12.2.1. kernel_modules buildroot package</a></h5>
+<h5 id="kernel_modules-buildroot-package"><a class="anchor" href="#kernel_modules-buildroot-package"></a><a class="link" href="#kernel_modules-buildroot-package">29.12.2.1. kernel_modules buildroot package</a></h5>
 <div class="paragraph">
 <p>Source: <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/buildroot_packages/kernel_modules/">buildroot_packages/kernel_modules/</a></p>
 </div>
@@ -27574,9 +27909,9 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="patches-directory"><a class="anchor" href="#patches-directory"></a><a class="link" href="#patches-directory">28.12.3. patches directory</a></h4>
+<h4 id="patches-directory"><a class="anchor" href="#patches-directory"></a><a class="link" href="#patches-directory">29.12.3. patches directory</a></h4>
 <div class="sect4">
-<h5 id="patches-global-directory"><a class="anchor" href="#patches-global-directory"></a><a class="link" href="#patches-global-directory">28.12.3.1. patches/global directory</a></h5>
+<h5 id="patches-global-directory"><a class="anchor" href="#patches-global-directory"></a><a class="link" href="#patches-global-directory">29.12.3.1. patches/global directory</a></h5>
 <div class="paragraph">
 <p>Has the following structure:</p>
 </div>
@@ -27593,7 +27928,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect4">
-<h5 id="patches-manual-directory"><a class="anchor" href="#patches-manual-directory"></a><a class="link" href="#patches-manual-directory">28.12.3.2. patches/manual directory</a></h5>
+<h5 id="patches-manual-directory"><a class="anchor" href="#patches-manual-directory"></a><a class="link" href="#patches-manual-directory">29.12.3.2. patches/manual directory</a></h5>
 <div class="paragraph">
 <p>Patches in this directory are never applied automatically: it is up to users to manually apply them before usage following the instructions in this documentation.</p>
 </div>
@@ -27603,7 +27938,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="rootfs_overlay"><a class="anchor" href="#rootfs_overlay"></a><a class="link" href="#rootfs_overlay">28.12.4. rootfs_overlay</a></h4>
+<h4 id="rootfs_overlay"><a class="anchor" href="#rootfs_overlay"></a><a class="link" href="#rootfs_overlay">29.12.4. rootfs_overlay</a></h4>
 <div class="paragraph">
 <p>We use this directory for:</p>
 </div>
@@ -27648,7 +27983,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="lkmc-c"><a class="anchor" href="#lkmc-c"></a><a class="link" href="#lkmc-c">28.12.5. lkmc.c</a></h4>
+<h4 id="lkmc-c"><a class="anchor" href="#lkmc-c"></a><a class="link" href="#lkmc-c">29.12.5. lkmc.c</a></h4>
 <div class="paragraph">
 <p>The files:</p>
 </div>
@@ -27678,7 +28013,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="rand_check-out"><a class="anchor" href="#rand_check-out"></a><a class="link" href="#rand_check-out">28.12.6. rand_check.out</a></h4>
+<h4 id="rand_check-out"><a class="anchor" href="#rand_check-out"></a><a class="link" href="#rand_check-out">29.12.6. rand_check.out</a></h4>
 <div class="paragraph">
 <p>Print out several parameters that normally change randomly from boot to boot:</p>
 </div>
@@ -27705,7 +28040,7 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect3">
-<h4 id="lkmc_home"><a class="anchor" href="#lkmc_home"></a><a class="link" href="#lkmc_home">28.12.7. lkmc_home</a></h4>
+<h4 id="lkmc_home"><a class="anchor" href="#lkmc_home"></a><a class="link" href="#lkmc_home">29.12.7. lkmc_home</a></h4>
 <div class="paragraph">
 <p><code>lkmc_home</code> refers to the target base directory in which we put all our custom built stuff, such as <a href="#userland-setup">userland executables</a> and <a href="#your-first-kernel-module-hack">kernel modules</a>.</p>
 </div>
@@ -27739,15 +28074,15 @@ git -C "$(./getvar buildroot_source_dir)" checkout -
 </div>
 </div>
 <div class="sect2">
-<h3 id="test-this-repo"><a class="anchor" href="#test-this-repo"></a><a class="link" href="#test-this-repo">28.13. Test this repo</a></h3>
+<h3 id="test-this-repo"><a class="anchor" href="#test-this-repo"></a><a class="link" href="#test-this-repo">29.13. Test this repo</a></h3>
 <div class="sect3">
-<h4 id="automated-tests"><a class="anchor" href="#automated-tests"></a><a class="link" href="#automated-tests">28.13.1. Automated tests</a></h4>
+<h4 id="automated-tests"><a class="anchor" href="#automated-tests"></a><a class="link" href="#automated-tests">29.13.1. Automated tests</a></h4>
 <div class="paragraph">
 <p>Run almost all tests:</p>
 </div>
 <div class="literalblock">
 <div class="content">
-<pre>./build-test --size 3 &amp;&amp; \
+<pre>./build-test --all-archs --all-emulators --size 3 &amp;&amp; \
 ./test --size 3
 echo $?</pre>
 </div>
@@ -27797,7 +28132,7 @@ echo $?</pre>
 <p><a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/test">test</a> does not all possible tests, because there are too many possible variations and that would take forever. The rationale is the same as for <code>./build all</code> and is explained in <code>./build --help</code>.</p>
 </div>
 <div class="sect4">
-<h5 id="test-arch-and-emulator-selection"><a class="anchor" href="#test-arch-and-emulator-selection"></a><a class="link" href="#test-arch-and-emulator-selection">28.13.1.1. Test arch and emulator selection</a></h5>
+<h5 id="test-arch-and-emulator-selection"><a class="anchor" href="#test-arch-and-emulator-selection"></a><a class="link" href="#test-arch-and-emulator-selection">29.13.1.1. Test arch and emulator selection</a></h5>
 <div class="paragraph">
 <p>You can select multiple archs and emulators of interest, as for an other command, with:</p>
 </div>
@@ -27830,7 +28165,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="quit-on-fail"><a class="anchor" href="#quit-on-fail"></a><a class="link" href="#quit-on-fail">28.13.1.2. Quit on fail</a></h5>
+<h5 id="quit-on-fail"><a class="anchor" href="#quit-on-fail"></a><a class="link" href="#quit-on-fail">29.13.1.2. Quit on fail</a></h5>
 <div class="paragraph">
 <p>By default, continue running even after the first failure happens, and they show a summary at the end.</p>
 </div>
@@ -27844,7 +28179,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="test-userland-in-full-system"><a class="anchor" href="#test-userland-in-full-system"></a><a class="link" href="#test-userland-in-full-system">28.13.1.3. Test userland in full system</a></h5>
+<h5 id="test-userland-in-full-system"><a class="anchor" href="#test-userland-in-full-system"></a><a class="link" href="#test-userland-in-full-system">29.13.1.3. Test userland in full system</a></h5>
 <div class="paragraph">
 <p>TODO: we really need a mechanism to automatically generate the test list automatically e.g. based on <a href="#path-properties">path_properties</a>, currently there are many tests missing, and we have to add everything manually which is very annoying.</p>
 </div>
@@ -27873,7 +28208,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="gdb-tests"><a class="anchor" href="#gdb-tests"></a><a class="link" href="#gdb-tests">28.13.1.4. GDB tests</a></h5>
+<h5 id="gdb-tests"><a class="anchor" href="#gdb-tests"></a><a class="link" href="#gdb-tests">29.13.1.4. GDB tests</a></h5>
 <div class="paragraph">
 <p>We have some <a href="https://github.com/pexpect/pexpect">pexpect</a> automated tests for GDB for both userland and baremetal programs!</p>
 </div>
@@ -27946,7 +28281,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="magic-failure-string"><a class="anchor" href="#magic-failure-string"></a><a class="link" href="#magic-failure-string">28.13.1.5. Magic failure string</a></h5>
+<h5 id="magic-failure-string"><a class="anchor" href="#magic-failure-string"></a><a class="link" href="#magic-failure-string">29.13.1.5. Magic failure string</a></h5>
 <div class="paragraph">
 <p>We do not know of any way to set the emulator exit status in QEMU arm full system.</p>
 </div>
@@ -28049,9 +28384,9 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect3">
-<h4 id="non-automated-tests"><a class="anchor" href="#non-automated-tests"></a><a class="link" href="#non-automated-tests">28.13.2. Non-automated tests</a></h4>
+<h4 id="non-automated-tests"><a class="anchor" href="#non-automated-tests"></a><a class="link" href="#non-automated-tests">29.13.2. Non-automated tests</a></h4>
 <div class="sect4">
-<h5 id="test-gdb-linux-kernel"><a class="anchor" href="#test-gdb-linux-kernel"></a><a class="link" href="#test-gdb-linux-kernel">28.13.2.1. Test GDB Linux kernel</a></h5>
+<h5 id="test-gdb-linux-kernel"><a class="anchor" href="#test-gdb-linux-kernel"></a><a class="link" href="#test-gdb-linux-kernel">29.13.2.1. Test GDB Linux kernel</a></h5>
 <div class="paragraph">
 <p>For the Linux kernel, do the following manual tests for now.</p>
 </div>
@@ -28089,7 +28424,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="test-the-internet"><a class="anchor" href="#test-the-internet"></a><a class="link" href="#test-the-internet">28.13.2.2. Test the Internet</a></h5>
+<h5 id="test-the-internet"><a class="anchor" href="#test-the-internet"></a><a class="link" href="#test-the-internet">29.13.2.2. Test the Internet</a></h5>
 <div class="paragraph">
 <p>You should also test that the Internet works:</p>
 </div>
@@ -28100,7 +28435,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect4">
-<h5 id="cli-script-tests"><a class="anchor" href="#cli-script-tests"></a><a class="link" href="#cli-script-tests">28.13.2.3. CLI script tests</a></h5>
+<h5 id="cli-script-tests"><a class="anchor" href="#cli-script-tests"></a><a class="link" href="#cli-script-tests">29.13.2.3. CLI script tests</a></h5>
 <div class="paragraph">
 <p><code>build-userland</code> and <code>test-executables</code> have a wide variety of target selection modes, and it was hard to keep them all working without some tests:</p>
 </div>
@@ -28118,7 +28453,7 @@ echo $?</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="bisection"><a class="anchor" href="#bisection"></a><a class="link" href="#bisection">28.14. Bisection</a></h3>
+<h3 id="bisection"><a class="anchor" href="#bisection"></a><a class="link" href="#bisection">29.14. Bisection</a></h3>
 <div class="paragraph">
 <p>When updating the Linux kernel, QEMU and gem5, things sometimes break.</p>
 </div>
@@ -28174,7 +28509,7 @@ git submodule update
 </div>
 </div>
 <div class="sect2">
-<h3 id="path-properties"><a class="anchor" href="#path-properties"></a><a class="link" href="#path-properties">28.15. path_properties</a></h3>
+<h3 id="path-properties"><a class="anchor" href="#path-properties"></a><a class="link" href="#path-properties">29.15. path_properties</a></h3>
 <div class="paragraph">
 <p>In order to build and run each userland and <a href="#baremetal-setup">baremetal</a> example properly, we need per-file metadata such as compiler flags and required number of cores.</p>
 </div>
@@ -28217,7 +28552,7 @@ git submodule update
 </div>
 </div>
 <div class="sect2">
-<h3 id="update-a-forked-submodule"><a class="anchor" href="#update-a-forked-submodule"></a><a class="link" href="#update-a-forked-submodule">28.16. Update a forked submodule</a></h3>
+<h3 id="update-a-forked-submodule"><a class="anchor" href="#update-a-forked-submodule"></a><a class="link" href="#update-a-forked-submodule">29.16. Update a forked submodule</a></h3>
 <div class="paragraph">
 <p>This is a template update procedure for submodules for which we have some patches on on top of mainline.</p>
 </div>
@@ -28247,9 +28582,9 @@ git commit -m "linux: update to ${next_mainline_revision}"</pre>
 </div>
 </div>
 <div class="sect2">
-<h3 id="release"><a class="anchor" href="#release"></a><a class="link" href="#release">28.17. Release</a></h3>
+<h3 id="release"><a class="anchor" href="#release"></a><a class="link" href="#release">29.17. Release</a></h3>
 <div class="sect3">
-<h4 id="release-procedure"><a class="anchor" href="#release-procedure"></a><a class="link" href="#release-procedure">28.17.1. Release procedure</a></h4>
+<h4 id="release-procedure"><a class="anchor" href="#release-procedure"></a><a class="link" href="#release-procedure">29.17.1. Release procedure</a></h4>
 <div class="paragraph">
 <p>Ensure that the <a href="#automated-tests">Automated tests</a> are passing on a clean build:</p>
 </div>
@@ -28330,7 +28665,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect3">
-<h4 id="release-zip"><a class="anchor" href="#release-zip"></a><a class="link" href="#release-zip">28.17.2. release-zip</a></h4>
+<h4 id="release-zip"><a class="anchor" href="#release-zip"></a><a class="link" href="#release-zip">29.17.2. release-zip</a></h4>
 <div class="paragraph">
 <p>Create a zip containing all files required for <a href="#prebuilt">Prebuilt setup</a>:</p>
 </div>
@@ -28355,7 +28690,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect3">
-<h4 id="release-upload"><a class="anchor" href="#release-upload"></a><a class="link" href="#release-upload">28.17.3. release-upload</a></h4>
+<h4 id="release-upload"><a class="anchor" href="#release-upload"></a><a class="link" href="#release-upload">29.17.3. release-upload</a></h4>
 <div class="paragraph">
 <p>After:</p>
 </div>
@@ -28403,9 +28738,9 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect2">
-<h3 id="design-rationale"><a class="anchor" href="#design-rationale"></a><a class="link" href="#design-rationale">28.18. Design rationale</a></h3>
+<h3 id="design-rationale"><a class="anchor" href="#design-rationale"></a><a class="link" href="#design-rationale">29.18. Design rationale</a></h3>
 <div class="sect3">
-<h4 id="design-goals"><a class="anchor" href="#design-goals"></a><a class="link" href="#design-goals">28.18.1. Design goals</a></h4>
+<h4 id="design-goals"><a class="anchor" href="#design-goals"></a><a class="link" href="#design-goals">29.18.1. Design goals</a></h4>
 <div class="paragraph">
 <p>This project was created to help me understand, modify and test low level system components by using system simulators.</p>
 </div>
@@ -28481,7 +28816,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect3">
-<h4 id="setup-trade-offs"><a class="anchor" href="#setup-trade-offs"></a><a class="link" href="#setup-trade-offs">28.18.2. Setup trade-offs</a></h4>
+<h4 id="setup-trade-offs"><a class="anchor" href="#setup-trade-offs"></a><a class="link" href="#setup-trade-offs">29.18.2. Setup trade-offs</a></h4>
 <div class="paragraph">
 <p>The trade-offs between the different <a href="#getting-started">setups</a> are basically a balance between:</p>
 </div>
@@ -28512,7 +28847,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect3">
-<h4 id="resource-tradeoff-guidelines"><a class="anchor" href="#resource-tradeoff-guidelines"></a><a class="link" href="#resource-tradeoff-guidelines">28.18.3. Resource tradeoff guidelines</a></h4>
+<h4 id="resource-tradeoff-guidelines"><a class="anchor" href="#resource-tradeoff-guidelines"></a><a class="link" href="#resource-tradeoff-guidelines">29.18.3. Resource tradeoff guidelines</a></h4>
 <div class="paragraph">
 <p>Choosing which features go into our default builds means making tradeoffs, here are our guidelines:</p>
 </div>
@@ -28557,7 +28892,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect3">
-<h4 id="linux-distro-choice"><a class="anchor" href="#linux-distro-choice"></a><a class="link" href="#linux-distro-choice">28.18.4. Linux distro choice</a></h4>
+<h4 id="linux-distro-choice"><a class="anchor" href="#linux-distro-choice"></a><a class="link" href="#linux-distro-choice">29.18.4. Linux distro choice</a></h4>
 <div class="paragraph">
 <p>We haven&#8217;t found the ultimate distro yet, here is a summary table of trade-offs that we care about: <a href="#table-lkmc-linux-distro-comparison">Comparison of Linux distros for usage in this repository</a></p>
 </div>
@@ -28660,9 +28995,9 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect2">
-<h3 id="soft-topics"><a class="anchor" href="#soft-topics"></a><a class="link" href="#soft-topics">28.19. Soft topics</a></h3>
+<h3 id="soft-topics"><a class="anchor" href="#soft-topics"></a><a class="link" href="#soft-topics">29.19. Soft topics</a></h3>
 <div class="sect3">
-<h4 id="fairy-tale"><a class="anchor" href="#fairy-tale"></a><a class="link" href="#fairy-tale">28.19.1. Fairy tale</a></h4>
+<h4 id="fairy-tale"><a class="anchor" href="#fairy-tale"></a><a class="link" href="#fairy-tale">29.19.1. Fairy tale</a></h4>
 <div class="quoteblock">
 <blockquote>
 <div class="paragraph">
@@ -28699,7 +29034,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect3">
-<h4 id="should-you-waste-your-life-with-systems-programming"><a class="anchor" href="#should-you-waste-your-life-with-systems-programming"></a><a class="link" href="#should-you-waste-your-life-with-systems-programming">28.19.2. Should you waste your life with systems programming?</a></h4>
+<h4 id="should-you-waste-your-life-with-systems-programming"><a class="anchor" href="#should-you-waste-your-life-with-systems-programming"></a><a class="link" href="#should-you-waste-your-life-with-systems-programming">29.19.2. Should you waste your life with systems programming?</a></h4>
 <div class="paragraph">
 <p>Being the hardcore person who fully understands an important complex system such as a computer, it does have a nice ring to it doesn&#8217;t it?</p>
 </div>
@@ -28784,7 +29119,7 @@ git push --follow-tags
 </div>
 </div>
 <div class="sect2">
-<h3 id="bibliography"><a class="anchor" href="#bibliography"></a><a class="link" href="#bibliography">28.20. Bibliography</a></h3>
+<h3 id="bibliography"><a class="anchor" href="#bibliography"></a><a class="link" href="#bibliography">29.20. Bibliography</a></h3>
 <div class="paragraph">
 <p>Runnable stuff:</p>
 </div>