mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-24 18:51:36 +01:00
584 lines
38 KiB
HTML
584 lines
38 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en">
|
||
<head>
|
||
<meta charset="UTF-8">
|
||
<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 2.0.11">
|
||
<meta name="description" content="The perfect emulation setup to study and develop the <<linux-kernel>> v5.9.2, kernel modules, <<qemu-buildroot-setup,QEMU>>, <<gem5-buildroot-setup,gem5>> and x86_64, ARMv7 and ARMv8 <<userland-assembly,userland>> and <<baremetal-setup,baremetal>> assembly, <<c,ANSI C>>, <<cpp,C++>> and <<posix,POSIX>>. <<gdb>> and <<kgdb>> just work. Powered by <<about-the-qemu-buildroot-setup,Buildroot>> and <<about-the-baremetal-setup,crosstool-NG>>. Highly automated. Thoroughly documented. Automated <<test-this-repo,tests>>. "Tested" in an Ubuntu 20.04 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>
|
||
/* Asciidoctor default stylesheet | MIT License | https://asciidoctor.org */
|
||
/* Uncomment @import statement to use as custom stylesheet */
|
||
/*@import "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";*/
|
||
article,aside,details,figcaption,figure,footer,header,hgroup,main,nav,section{display:block}
|
||
audio,video{display:inline-block}
|
||
audio:not([controls]){display:none;height:0}
|
||
html{font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}
|
||
a{background:none}
|
||
a:focus{outline:thin dotted}
|
||
a:active,a:hover{outline:0}
|
||
h1{font-size:2em;margin:.67em 0}
|
||
abbr[title]{border-bottom:1px dotted}
|
||
b,strong{font-weight:bold}
|
||
dfn{font-style:italic}
|
||
hr{-moz-box-sizing:content-box;box-sizing:content-box;height:0}
|
||
mark{background:#ff0;color:#000}
|
||
code,kbd,pre,samp{font-family:monospace;font-size:1em}
|
||
pre{white-space:pre-wrap}
|
||
q{quotes:"\201C" "\201D" "\2018" "\2019"}
|
||
small{font-size:80%}
|
||
sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}
|
||
sup{top:-.5em}
|
||
sub{bottom:-.25em}
|
||
img{border:0}
|
||
svg:not(:root){overflow:hidden}
|
||
figure{margin:0}
|
||
fieldset{border:1px solid silver;margin:0 2px;padding:.35em .625em .75em}
|
||
legend{border:0;padding:0}
|
||
button,input,select,textarea{font-family:inherit;font-size:100%;margin:0}
|
||
button,input{line-height:normal}
|
||
button,select{text-transform:none}
|
||
button,html input[type="button"],input[type="reset"],input[type="submit"]{-webkit-appearance:button;cursor:pointer}
|
||
button[disabled],html input[disabled]{cursor:default}
|
||
input[type="checkbox"],input[type="radio"]{box-sizing:border-box;padding:0}
|
||
button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0}
|
||
textarea{overflow:auto;vertical-align:top}
|
||
table{border-collapse:collapse;border-spacing:0}
|
||
*,*::before,*::after{-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box}
|
||
html,body{font-size:100%}
|
||
body{background:#fff;color:rgba(0,0,0,.8);padding:0;margin:0;font-family:"Noto Serif","DejaVu Serif",serif;font-weight:400;font-style:normal;line-height:1;position:relative;cursor:auto;tab-size:4;word-wrap:anywhere;-moz-osx-font-smoothing:grayscale;-webkit-font-smoothing:antialiased}
|
||
a:hover{cursor:pointer}
|
||
img,object,embed{max-width:100%;height:auto}
|
||
object,embed{height:100%}
|
||
img{-ms-interpolation-mode:bicubic}
|
||
.left{float:left!important}
|
||
.right{float:right!important}
|
||
.text-left{text-align:left!important}
|
||
.text-right{text-align:right!important}
|
||
.text-center{text-align:center!important}
|
||
.text-justify{text-align:justify!important}
|
||
.hide{display:none}
|
||
img,object,svg{display:inline-block;vertical-align:middle}
|
||
textarea{height:auto;min-height:50px}
|
||
select{width:100%}
|
||
.subheader,.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{line-height:1.45;color:#7a2518;font-weight:400;margin-top:0;margin-bottom:.25em}
|
||
div,dl,dt,dd,ul,ol,li,h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6,pre,form,p,blockquote,th,td{margin:0;padding:0}
|
||
a{color:#2156a5;text-decoration:underline;line-height:inherit}
|
||
a:hover,a:focus{color:#1d4b8f}
|
||
a img{border:0}
|
||
p{font-family:inherit;font-weight:400;font-size:1em;line-height:1.6;margin-bottom:1.25em;text-rendering:optimizeLegibility}
|
||
p aside{font-size:.875em;line-height:1.35;font-style:italic}
|
||
h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{font-family:"Open Sans","DejaVu Sans",sans-serif;font-weight:300;font-style:normal;color:#ba3925;text-rendering:optimizeLegibility;margin-top:1em;margin-bottom:.5em;line-height:1.0125em}
|
||
h1 small,h2 small,h3 small,#toctitle small,.sidebarblock>.content>.title small,h4 small,h5 small,h6 small{font-size:60%;color:#e99b8f;line-height:0}
|
||
h1{font-size:2.125em}
|
||
h2{font-size:1.6875em}
|
||
h3,#toctitle,.sidebarblock>.content>.title{font-size:1.375em}
|
||
h4,h5{font-size:1.125em}
|
||
h6{font-size:1em}
|
||
hr{border:solid #dddddf;border-width:1px 0 0;clear:both;margin:1.25em 0 1.1875em;height:0}
|
||
em,i{font-style:italic;line-height:inherit}
|
||
strong,b{font-weight:bold;line-height:inherit}
|
||
small{font-size:60%;line-height:inherit}
|
||
code{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;color:rgba(0,0,0,.9)}
|
||
ul,ol,dl{font-size:1em;line-height:1.6;margin-bottom:1.25em;list-style-position:outside;font-family:inherit}
|
||
ul,ol{margin-left:1.5em}
|
||
ul li ul,ul li ol{margin-left:1.25em;margin-bottom:0;font-size:1em}
|
||
ul.square li ul,ul.circle li ul,ul.disc li ul{list-style:inherit}
|
||
ul.square{list-style-type:square}
|
||
ul.circle{list-style-type:circle}
|
||
ul.disc{list-style-type:disc}
|
||
ol li ul,ol li ol{margin-left:1.25em;margin-bottom:0}
|
||
dl dt{margin-bottom:.3125em;font-weight:bold}
|
||
dl dd{margin-bottom:1.25em}
|
||
abbr,acronym{text-transform:uppercase;font-size:90%;color:rgba(0,0,0,.8);border-bottom:1px dotted #ddd;cursor:help}
|
||
abbr{text-transform:none}
|
||
blockquote{margin:0 0 1.25em;padding:.5625em 1.25em 0 1.1875em;border-left:1px solid #ddd}
|
||
blockquote cite{display:block;font-size:.9375em;color:rgba(0,0,0,.6)}
|
||
blockquote cite::before{content:"\2014 \0020"}
|
||
blockquote cite a,blockquote cite a:visited{color:rgba(0,0,0,.6)}
|
||
blockquote,blockquote p{line-height:1.6;color:rgba(0,0,0,.85)}
|
||
@media screen and (min-width:768px){h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2}
|
||
h1{font-size:2.75em}
|
||
h2{font-size:2.3125em}
|
||
h3,#toctitle,.sidebarblock>.content>.title{font-size:1.6875em}
|
||
h4{font-size:1.4375em}}
|
||
table{background:#fff;margin-bottom:1.25em;border:solid 1px #dedede}
|
||
table thead,table tfoot{background:#f7f8f7}
|
||
table thead tr th,table thead tr td,table tfoot tr th,table tfoot tr td{padding:.5em .625em .625em;font-size:inherit;color:rgba(0,0,0,.8);text-align:left}
|
||
table tr th,table tr td{padding:.5625em .625em;font-size:inherit;color:rgba(0,0,0,.8)}
|
||
table tr.even,table tr.alt{background:#f8f8f7}
|
||
table thead tr th,table tfoot tr th,table tbody tr td,table tr td,table tfoot tr td{display:table-cell;line-height:1.6}
|
||
h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2;word-spacing:-.05em}
|
||
h1 strong,h2 strong,h3 strong,#toctitle strong,.sidebarblock>.content>.title strong,h4 strong,h5 strong,h6 strong{font-weight:400}
|
||
.center{margin-left:auto;margin-right:auto}
|
||
.stretch{width:100%}
|
||
.clearfix::before,.clearfix::after,.float-group::before,.float-group::after{content:" ";display:table}
|
||
.clearfix::after,.float-group::after{clear:both}
|
||
:not(pre).nobreak{word-wrap:normal}
|
||
:not(pre).nowrap{white-space:nowrap}
|
||
:not(pre).pre-wrap{white-space:pre-wrap}
|
||
:not(pre):not([class^=L])>code{font-size:.9375em;font-style:normal!important;letter-spacing:0;padding:.1em .5ex;word-spacing:-.15em;background:#f7f7f8;-webkit-border-radius:4px;border-radius:4px;line-height:1.45;text-rendering:optimizeSpeed}
|
||
pre{color:rgba(0,0,0,.9);font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;line-height:1.45;text-rendering:optimizeSpeed}
|
||
pre code,pre pre{color:inherit;font-size:inherit;line-height:inherit}
|
||
pre>code{display:block}
|
||
pre.nowrap,pre.nowrap pre{white-space:pre;word-wrap:normal}
|
||
em em{font-style:normal}
|
||
strong strong{font-weight:400}
|
||
.keyseq{color:rgba(51,51,51,.8)}
|
||
kbd{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;display:inline-block;color:rgba(0,0,0,.8);font-size:.65em;line-height:1.45;background:#f7f7f7;border:1px solid #ccc;-webkit-border-radius:3px;border-radius:3px;-webkit-box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em white inset;box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em #fff inset;margin:0 .15em;padding:.2em .5em;vertical-align:middle;position:relative;top:-.1em;white-space:nowrap}
|
||
.keyseq kbd:first-child{margin-left:0}
|
||
.keyseq kbd:last-child{margin-right:0}
|
||
.menuseq,.menuref{color:#000}
|
||
.menuseq b:not(.caret),.menuref{font-weight:inherit}
|
||
.menuseq{word-spacing:-.02em}
|
||
.menuseq b.caret{font-size:1.25em;line-height:.8}
|
||
.menuseq i.caret{font-weight:bold;text-align:center;width:.45em}
|
||
b.button::before,b.button::after{position:relative;top:-1px;font-weight:400}
|
||
b.button::before{content:"[";padding:0 3px 0 2px}
|
||
b.button::after{content:"]";padding:0 2px 0 3px}
|
||
p a>code:hover{color:rgba(0,0,0,.9)}
|
||
#header,#content,#footnotes,#footer{width:100%;margin-left:auto;margin-right:auto;margin-top:0;margin-bottom:0;max-width:62.5em;*zoom:1;position:relative;padding-left:.9375em;padding-right:.9375em}
|
||
#header::before,#header::after,#content::before,#content::after,#footnotes::before,#footnotes::after,#footer::before,#footer::after{content:" ";display:table}
|
||
#header::after,#content::after,#footnotes::after,#footer::after{clear:both}
|
||
#content{margin-top:1.25em}
|
||
#content::before{content:none}
|
||
#header>h1:first-child{color:rgba(0,0,0,.85);margin-top:2.25rem;margin-bottom:0}
|
||
#header>h1:first-child+#toc{margin-top:8px;border-top:1px solid #dddddf}
|
||
#header>h1:only-child,body.toc2 #header>h1:nth-last-child(2){border-bottom:1px solid #dddddf;padding-bottom:8px}
|
||
#header .details{border-bottom:1px solid #dddddf;line-height:1.45;padding-top:.25em;padding-bottom:.25em;padding-left:.25em;color:rgba(0,0,0,.6);display:-ms-flexbox;display:-webkit-flex;display:flex;-ms-flex-flow:row wrap;-webkit-flex-flow:row wrap;flex-flow:row wrap}
|
||
#header .details span:first-child{margin-left:-.125em}
|
||
#header .details span.email a{color:rgba(0,0,0,.85)}
|
||
#header .details br{display:none}
|
||
#header .details br+span::before{content:"\00a0\2013\00a0"}
|
||
#header .details br+span.author::before{content:"\00a0\22c5\00a0";color:rgba(0,0,0,.85)}
|
||
#header .details br+span#revremark::before{content:"\00a0|\00a0"}
|
||
#header #revnumber{text-transform:capitalize}
|
||
#header #revnumber::after{content:"\00a0"}
|
||
#content>h1:first-child:not([class]){color:rgba(0,0,0,.85);border-bottom:1px solid #dddddf;padding-bottom:8px;margin-top:0;padding-top:1rem;margin-bottom:1.25rem}
|
||
#toc{border-bottom:1px solid #e7e7e9;padding-bottom:.5em}
|
||
#toc>ul{margin-left:.125em}
|
||
#toc ul.sectlevel0>li>a{font-style:italic}
|
||
#toc ul.sectlevel0 ul.sectlevel1{margin:.5em 0}
|
||
#toc ul{font-family:"Open Sans","DejaVu Sans",sans-serif;list-style-type:none}
|
||
#toc li{line-height:1.3334;margin-top:.3334em}
|
||
#toc a{text-decoration:none}
|
||
#toc a:active{text-decoration:underline}
|
||
#toctitle{color:#7a2518;font-size:1.2em}
|
||
@media screen and (min-width:768px){#toctitle{font-size:1.375em}
|
||
body.toc2{padding-left:15em;padding-right:0}
|
||
#toc.toc2{margin-top:0!important;background:#f8f8f7;position:fixed;width:15em;left:0;top:0;border-right:1px solid #e7e7e9;border-top-width:0!important;border-bottom-width:0!important;z-index:1000;padding:1.25em 1em;height:100%;overflow:auto}
|
||
#toc.toc2 #toctitle{margin-top:0;margin-bottom:.8rem;font-size:1.2em}
|
||
#toc.toc2>ul{font-size:.9em;margin-bottom:0}
|
||
#toc.toc2 ul ul{margin-left:0;padding-left:1em}
|
||
#toc.toc2 ul.sectlevel0 ul.sectlevel1{padding-left:0;margin-top:.5em;margin-bottom:.5em}
|
||
body.toc2.toc-right{padding-left:0;padding-right:15em}
|
||
body.toc2.toc-right #toc.toc2{border-right-width:0;border-left:1px solid #e7e7e9;left:auto;right:0}}
|
||
@media screen and (min-width:1280px){body.toc2{padding-left:20em;padding-right:0}
|
||
#toc.toc2{width:20em}
|
||
#toc.toc2 #toctitle{font-size:1.375em}
|
||
#toc.toc2>ul{font-size:.95em}
|
||
#toc.toc2 ul ul{padding-left:1.25em}
|
||
body.toc2.toc-right{padding-left:0;padding-right:20em}}
|
||
#content #toc{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
|
||
#content #toc>:first-child{margin-top:0}
|
||
#content #toc>:last-child{margin-bottom:0}
|
||
#footer{max-width:none;background:rgba(0,0,0,.8);padding:1.25em}
|
||
#footer-text{color:rgba(255,255,255,.8);line-height:1.44}
|
||
#content{margin-bottom:.625em}
|
||
.sect1{padding-bottom:.625em}
|
||
@media screen and (min-width:768px){#content{margin-bottom:1.25em}
|
||
.sect1{padding-bottom:1.25em}}
|
||
.sect1:last-child{padding-bottom:0}
|
||
.sect1+.sect1{border-top:1px solid #e7e7e9}
|
||
#content h1>a.anchor,h2>a.anchor,h3>a.anchor,#toctitle>a.anchor,.sidebarblock>.content>.title>a.anchor,h4>a.anchor,h5>a.anchor,h6>a.anchor{position:absolute;z-index:1001;width:1.5ex;margin-left:-1.5ex;display:block;text-decoration:none!important;visibility:hidden;text-align:center;font-weight:400}
|
||
#content h1>a.anchor::before,h2>a.anchor::before,h3>a.anchor::before,#toctitle>a.anchor::before,.sidebarblock>.content>.title>a.anchor::before,h4>a.anchor::before,h5>a.anchor::before,h6>a.anchor::before{content:"\00A7";font-size:.85em;display:block;padding-top:.1em}
|
||
#content h1:hover>a.anchor,#content h1>a.anchor:hover,h2:hover>a.anchor,h2>a.anchor:hover,h3:hover>a.anchor,#toctitle:hover>a.anchor,.sidebarblock>.content>.title:hover>a.anchor,h3>a.anchor:hover,#toctitle>a.anchor:hover,.sidebarblock>.content>.title>a.anchor:hover,h4:hover>a.anchor,h4>a.anchor:hover,h5:hover>a.anchor,h5>a.anchor:hover,h6:hover>a.anchor,h6>a.anchor:hover{visibility:visible}
|
||
#content h1>a.link,h2>a.link,h3>a.link,#toctitle>a.link,.sidebarblock>.content>.title>a.link,h4>a.link,h5>a.link,h6>a.link{color:#ba3925;text-decoration:none}
|
||
#content h1>a.link:hover,h2>a.link:hover,h3>a.link:hover,#toctitle>a.link:hover,.sidebarblock>.content>.title>a.link:hover,h4>a.link:hover,h5>a.link:hover,h6>a.link:hover{color:#a53221}
|
||
details,.audioblock,.imageblock,.literalblock,.listingblock,.stemblock,.videoblock{margin-bottom:1.25em}
|
||
details>summary:first-of-type{cursor:pointer;display:list-item;outline:none;margin-bottom:.75em}
|
||
.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{text-rendering:optimizeLegibility;text-align:left;font-family:"Noto Serif","DejaVu Serif",serif;font-size:1rem;font-style:italic}
|
||
table.tableblock.fit-content>caption.title{white-space:nowrap;width:0}
|
||
.paragraph.lead>p,#preamble>.sectionbody>[class="paragraph"]:first-of-type p{font-size:1.21875em;line-height:1.6;color:rgba(0,0,0,.85)}
|
||
table.tableblock #preamble>.sectionbody>[class="paragraph"]:first-of-type p{font-size:inherit}
|
||
.admonitionblock>table{border-collapse:separate;border:0;background:none;width:100%}
|
||
.admonitionblock>table td.icon{text-align:center;width:80px}
|
||
.admonitionblock>table td.icon img{max-width:none}
|
||
.admonitionblock>table td.icon .title{font-weight:bold;font-family:"Open Sans","DejaVu Sans",sans-serif;text-transform:uppercase}
|
||
.admonitionblock>table td.content{padding-left:1.125em;padding-right:1.25em;border-left:1px solid #dddddf;color:rgba(0,0,0,.6)}
|
||
.admonitionblock>table td.content>:last-child>:last-child{margin-bottom:0}
|
||
.exampleblock>.content{border-style:solid;border-width:1px;border-color:#e6e6e6;margin-bottom:1.25em;padding:1.25em;background:#fff;-webkit-border-radius:4px;border-radius:4px}
|
||
.exampleblock>.content>:first-child{margin-top:0}
|
||
.exampleblock>.content>:last-child{margin-bottom:0}
|
||
.sidebarblock{border-style:solid;border-width:1px;border-color:#dbdbd6;margin-bottom:1.25em;padding:1.25em;background:#f3f3f2;-webkit-border-radius:4px;border-radius:4px}
|
||
.sidebarblock>:first-child{margin-top:0}
|
||
.sidebarblock>:last-child{margin-bottom:0}
|
||
.sidebarblock>.content>.title{color:#7a2518;margin-top:0;text-align:center}
|
||
.exampleblock>.content>:last-child>:last-child,.exampleblock>.content .olist>ol>li:last-child>:last-child,.exampleblock>.content .ulist>ul>li:last-child>:last-child,.exampleblock>.content .qlist>ol>li:last-child>:last-child,.sidebarblock>.content>:last-child>:last-child,.sidebarblock>.content .olist>ol>li:last-child>:last-child,.sidebarblock>.content .ulist>ul>li:last-child>:last-child,.sidebarblock>.content .qlist>ol>li:last-child>:last-child{margin-bottom:0}
|
||
.literalblock pre,.listingblock>.content>pre{-webkit-border-radius:4px;border-radius:4px;overflow-x:auto;padding:1em;font-size:.8125em}
|
||
@media screen and (min-width:768px){.literalblock pre,.listingblock>.content>pre{font-size:.90625em}}
|
||
@media screen and (min-width:1280px){.literalblock pre,.listingblock>.content>pre{font-size:1em}}
|
||
.literalblock pre,.listingblock>.content>pre:not(.highlight),.listingblock>.content>pre[class="highlight"],.listingblock>.content>pre[class^="highlight "]{background:#f7f7f8}
|
||
.literalblock.output pre{color:#f7f7f8;background:rgba(0,0,0,.9)}
|
||
.listingblock>.content{position:relative}
|
||
.listingblock code[data-lang]::before{display:none;content:attr(data-lang);position:absolute;font-size:.75em;top:.425rem;right:.5rem;line-height:1;text-transform:uppercase;color:inherit;opacity:.5}
|
||
.listingblock:hover code[data-lang]::before{display:block}
|
||
.listingblock.terminal pre .command::before{content:attr(data-prompt);padding-right:.5em;color:inherit;opacity:.5}
|
||
.listingblock.terminal pre .command:not([data-prompt])::before{content:"$"}
|
||
.listingblock pre.highlightjs{padding:0}
|
||
.listingblock pre.highlightjs>code{padding:1em;-webkit-border-radius:4px;border-radius:4px}
|
||
.listingblock pre.prettyprint{border-width:0}
|
||
.prettyprint{background:#f7f7f8}
|
||
pre.prettyprint .linenums{line-height:1.45;margin-left:2em}
|
||
pre.prettyprint li{background:none;list-style-type:inherit;padding-left:0}
|
||
pre.prettyprint li code[data-lang]::before{opacity:1}
|
||
pre.prettyprint li:not(:first-child) code[data-lang]::before{display:none}
|
||
table.linenotable{border-collapse:separate;border:0;margin-bottom:0;background:none}
|
||
table.linenotable td[class]{color:inherit;vertical-align:top;padding:0;line-height:inherit;white-space:normal}
|
||
table.linenotable td.code{padding-left:.75em}
|
||
table.linenotable td.linenos{border-right:1px solid currentColor;opacity:.35;padding-right:.5em}
|
||
pre.pygments .lineno{border-right:1px solid currentColor;opacity:.35;display:inline-block;margin-right:.75em}
|
||
pre.pygments .lineno::before{content:"";margin-right:-.125em}
|
||
.quoteblock{margin:0 1em 1.25em 1.5em;display:table}
|
||
.quoteblock:not(.excerpt)>.title{margin-left:-1.5em;margin-bottom:.75em}
|
||
.quoteblock blockquote,.quoteblock p{color:rgba(0,0,0,.85);font-size:1.15rem;line-height:1.75;word-spacing:.1em;letter-spacing:0;font-style:italic;text-align:justify}
|
||
.quoteblock blockquote{margin:0;padding:0;border:0}
|
||
.quoteblock blockquote::before{content:"\201c";float:left;font-size:2.75em;font-weight:bold;line-height:.6em;margin-left:-.6em;color:#7a2518;text-shadow:0 1px 2px rgba(0,0,0,.1)}
|
||
.quoteblock blockquote>.paragraph:last-child p{margin-bottom:0}
|
||
.quoteblock .attribution{margin-top:.75em;margin-right:.5ex;text-align:right}
|
||
.verseblock{margin:0 1em 1.25em}
|
||
.verseblock pre{font-family:"Open Sans","DejaVu Sans",sans;font-size:1.15rem;color:rgba(0,0,0,.85);font-weight:300;text-rendering:optimizeLegibility}
|
||
.verseblock pre strong{font-weight:400}
|
||
.verseblock .attribution{margin-top:1.25rem;margin-left:.5ex}
|
||
.quoteblock .attribution,.verseblock .attribution{font-size:.9375em;line-height:1.45;font-style:italic}
|
||
.quoteblock .attribution br,.verseblock .attribution br{display:none}
|
||
.quoteblock .attribution cite,.verseblock .attribution cite{display:block;letter-spacing:-.025em;color:rgba(0,0,0,.6)}
|
||
.quoteblock.abstract blockquote::before,.quoteblock.excerpt blockquote::before,.quoteblock .quoteblock blockquote::before{display:none}
|
||
.quoteblock.abstract blockquote,.quoteblock.abstract p,.quoteblock.excerpt blockquote,.quoteblock.excerpt p,.quoteblock .quoteblock blockquote,.quoteblock .quoteblock p{line-height:1.6;word-spacing:0}
|
||
.quoteblock.abstract{margin:0 1em 1.25em;display:block}
|
||
.quoteblock.abstract>.title{margin:0 0 .375em;font-size:1.15em;text-align:center}
|
||
.quoteblock.excerpt>blockquote,.quoteblock .quoteblock{padding:0 0 .25em 1em;border-left:.25em solid #dddddf}
|
||
.quoteblock.excerpt,.quoteblock .quoteblock{margin-left:0}
|
||
.quoteblock.excerpt blockquote,.quoteblock.excerpt p,.quoteblock .quoteblock blockquote,.quoteblock .quoteblock p{color:inherit;font-size:1.0625rem}
|
||
.quoteblock.excerpt .attribution,.quoteblock .quoteblock .attribution{color:inherit;text-align:left;margin-right:0}
|
||
table.tableblock{max-width:100%}
|
||
p.tableblock:last-child{margin-bottom:0}
|
||
td.tableblock>.content{margin-bottom:1.25em}
|
||
td.tableblock>.content>:last-child{margin-bottom:-1.25em}
|
||
table.tableblock,th.tableblock,td.tableblock{border:0 solid #dedede}
|
||
table.grid-all>*>tr>*{border-width:1px}
|
||
table.grid-cols>*>tr>*{border-width:0 1px}
|
||
table.grid-rows>*>tr>*{border-width:1px 0}
|
||
table.frame-all{border-width:1px}
|
||
table.frame-ends{border-width:1px 0}
|
||
table.frame-sides{border-width:0 1px}
|
||
table.frame-none>colgroup+*>:first-child>*,table.frame-sides>colgroup+*>:first-child>*{border-top-width:0}
|
||
table.frame-none>:last-child>:last-child>*,table.frame-sides>:last-child>:last-child>*{border-bottom-width:0}
|
||
table.frame-none>*>tr>:first-child,table.frame-ends>*>tr>:first-child{border-left-width:0}
|
||
table.frame-none>*>tr>:last-child,table.frame-ends>*>tr>:last-child{border-right-width:0}
|
||
table.stripes-all tr,table.stripes-odd tr:nth-of-type(odd),table.stripes-even tr:nth-of-type(even),table.stripes-hover tr:hover{background:#f8f8f7}
|
||
th.halign-left,td.halign-left{text-align:left}
|
||
th.halign-right,td.halign-right{text-align:right}
|
||
th.halign-center,td.halign-center{text-align:center}
|
||
th.valign-top,td.valign-top{vertical-align:top}
|
||
th.valign-bottom,td.valign-bottom{vertical-align:bottom}
|
||
th.valign-middle,td.valign-middle{vertical-align:middle}
|
||
table thead th,table tfoot th{font-weight:bold}
|
||
tbody tr th{display:table-cell;line-height:1.6;background:#f7f8f7}
|
||
tbody tr th,tbody tr th p,tfoot tr th,tfoot tr th p{color:rgba(0,0,0,.8);font-weight:bold}
|
||
p.tableblock>code:only-child{background:none;padding:0}
|
||
p.tableblock{font-size:1em}
|
||
ol{margin-left:1.75em}
|
||
ul li ol{margin-left:1.5em}
|
||
dl dd{margin-left:1.125em}
|
||
dl dd:last-child,dl dd:last-child>:last-child{margin-bottom:0}
|
||
ol>li p,ul>li p,ul dd,ol dd,.olist .olist,.ulist .ulist,.ulist .olist,.olist .ulist{margin-bottom:.625em}
|
||
ul.checklist,ul.none,ol.none,ul.no-bullet,ol.no-bullet,ol.unnumbered,ul.unstyled,ol.unstyled{list-style-type:none}
|
||
ul.no-bullet,ol.no-bullet,ol.unnumbered{margin-left:.625em}
|
||
ul.unstyled,ol.unstyled{margin-left:0}
|
||
ul.checklist{margin-left:.625em}
|
||
ul.checklist li>p:first-child>.fa-square-o:first-child,ul.checklist li>p:first-child>.fa-check-square-o:first-child{width:1.25em;font-size:.8em;position:relative;bottom:.125em}
|
||
ul.checklist li>p:first-child>input[type="checkbox"]:first-child{margin-right:.25em}
|
||
ul.inline{display:-ms-flexbox;display:-webkit-box;display:flex;-ms-flex-flow:row wrap;-webkit-flex-flow:row wrap;flex-flow:row wrap;list-style:none;margin:0 0 .625em -1.25em}
|
||
ul.inline>li{margin-left:1.25em}
|
||
.unstyled dl dt{font-weight:400;font-style:normal}
|
||
ol.arabic{list-style-type:decimal}
|
||
ol.decimal{list-style-type:decimal-leading-zero}
|
||
ol.loweralpha{list-style-type:lower-alpha}
|
||
ol.upperalpha{list-style-type:upper-alpha}
|
||
ol.lowerroman{list-style-type:lower-roman}
|
||
ol.upperroman{list-style-type:upper-roman}
|
||
ol.lowergreek{list-style-type:lower-greek}
|
||
.hdlist>table,.colist>table{border:0;background:none}
|
||
.hdlist>table>tbody>tr,.colist>table>tbody>tr{background:none}
|
||
td.hdlist1,td.hdlist2{vertical-align:top;padding:0 .625em}
|
||
td.hdlist1{font-weight:bold;padding-bottom:1.25em}
|
||
.literalblock+.colist,.listingblock+.colist{margin-top:-.5em}
|
||
.colist td:not([class]):first-child{padding:.4em .75em 0;line-height:1;vertical-align:top}
|
||
.colist td:not([class]):first-child img{max-width:none}
|
||
.colist td:not([class]):last-child{padding:.25em 0}
|
||
.thumb,.th{line-height:0;display:inline-block;border:solid 4px #fff;-webkit-box-shadow:0 0 0 1px #ddd;box-shadow:0 0 0 1px #ddd}
|
||
.imageblock.left{margin:.25em .625em 1.25em 0}
|
||
.imageblock.right{margin:.25em 0 1.25em .625em}
|
||
.imageblock>.title{margin-bottom:0}
|
||
.imageblock.thumb,.imageblock.th{border-width:6px}
|
||
.imageblock.thumb>.title,.imageblock.th>.title{padding:0 .125em}
|
||
.image.left,.image.right{margin-top:.25em;margin-bottom:.25em;display:inline-block;line-height:0}
|
||
.image.left{margin-right:.625em}
|
||
.image.right{margin-left:.625em}
|
||
a.image{text-decoration:none;display:inline-block}
|
||
a.image object{pointer-events:none}
|
||
sup.footnote,sup.footnoteref{font-size:.875em;position:static;vertical-align:super}
|
||
sup.footnote a,sup.footnoteref a{text-decoration:none}
|
||
sup.footnote a:active,sup.footnoteref a:active{text-decoration:underline}
|
||
#footnotes{padding-top:.75em;padding-bottom:.75em;margin-bottom:.625em}
|
||
#footnotes hr{width:20%;min-width:6.25em;margin:-.25em 0 .75em;border-width:1px 0 0}
|
||
#footnotes .footnote{padding:0 .375em 0 .225em;line-height:1.3334;font-size:.875em;margin-left:1.2em;margin-bottom:.2em}
|
||
#footnotes .footnote a:first-of-type{font-weight:bold;text-decoration:none;margin-left:-1.05em}
|
||
#footnotes .footnote:last-of-type{margin-bottom:0}
|
||
#content #footnotes{margin-top:-.625em;margin-bottom:0;padding:.75em 0}
|
||
.gist .file-data>table{border:0;background:#fff;width:100%;margin-bottom:0}
|
||
.gist .file-data>table td.line-data{width:99%}
|
||
div.unbreakable{page-break-inside:avoid}
|
||
.big{font-size:larger}
|
||
.small{font-size:smaller}
|
||
.underline{text-decoration:underline}
|
||
.overline{text-decoration:overline}
|
||
.line-through{text-decoration:line-through}
|
||
.aqua{color:#00bfbf}
|
||
.aqua-background{background:#00fafa}
|
||
.black{color:#000}
|
||
.black-background{background:#000}
|
||
.blue{color:#0000bf}
|
||
.blue-background{background:#0000fa}
|
||
.fuchsia{color:#bf00bf}
|
||
.fuchsia-background{background:#fa00fa}
|
||
.gray{color:#606060}
|
||
.gray-background{background:#7d7d7d}
|
||
.green{color:#006000}
|
||
.green-background{background:#007d00}
|
||
.lime{color:#00bf00}
|
||
.lime-background{background:#00fa00}
|
||
.maroon{color:#600000}
|
||
.maroon-background{background:#7d0000}
|
||
.navy{color:#000060}
|
||
.navy-background{background:#00007d}
|
||
.olive{color:#606000}
|
||
.olive-background{background:#7d7d00}
|
||
.purple{color:#600060}
|
||
.purple-background{background:#7d007d}
|
||
.red{color:#bf0000}
|
||
.red-background{background:#fa0000}
|
||
.silver{color:#909090}
|
||
.silver-background{background:#bcbcbc}
|
||
.teal{color:#006060}
|
||
.teal-background{background:#007d7d}
|
||
.white{color:#bfbfbf}
|
||
.white-background{background:#fafafa}
|
||
.yellow{color:#bfbf00}
|
||
.yellow-background{background:#fafa00}
|
||
span.icon>.fa{cursor:default}
|
||
a span.icon>.fa{cursor:inherit}
|
||
.admonitionblock td.icon [class^="fa icon-"]{font-size:2.5em;text-shadow:1px 1px 2px rgba(0,0,0,.5);cursor:default}
|
||
.admonitionblock td.icon .icon-note::before{content:"\f05a";color:#19407c}
|
||
.admonitionblock td.icon .icon-tip::before{content:"\f0eb";text-shadow:1px 1px 2px rgba(155,155,0,.8);color:#111}
|
||
.admonitionblock td.icon .icon-warning::before{content:"\f071";color:#bf6900}
|
||
.admonitionblock td.icon .icon-caution::before{content:"\f06d";color:#bf3400}
|
||
.admonitionblock td.icon .icon-important::before{content:"\f06a";color:#bf0000}
|
||
.conum[data-value]{display:inline-block;color:#fff!important;background:rgba(0,0,0,.8);-webkit-border-radius:50%;border-radius:50%;text-align:center;font-size:.75em;width:1.67em;height:1.67em;line-height:1.67em;font-family:"Open Sans","DejaVu Sans",sans-serif;font-style:normal;font-weight:bold}
|
||
.conum[data-value] *{color:#fff!important}
|
||
.conum[data-value]+b{display:none}
|
||
.conum[data-value]::after{content:attr(data-value)}
|
||
pre .conum[data-value]{position:relative;top:-.125em}
|
||
b.conum *{color:inherit!important}
|
||
.conum:not([data-value]):empty{display:none}
|
||
dt,th.tableblock,td.content,div.footnote{text-rendering:optimizeLegibility}
|
||
h1,h2,p,td.content,span.alt{letter-spacing:-.01em}
|
||
p strong,td.content strong,div.footnote strong{letter-spacing:-.005em}
|
||
p,blockquote,dt,td.content,span.alt{font-size:1.0625rem}
|
||
p{margin-bottom:1.25rem}
|
||
.sidebarblock p,.sidebarblock dt,.sidebarblock td.content,p.tableblock{font-size:1em}
|
||
.exampleblock>.content{background:#fffef7;border-color:#e0e0dc;-webkit-box-shadow:0 1px 4px #e0e0dc;box-shadow:0 1px 4px #e0e0dc}
|
||
.print-only{display:none!important}
|
||
@page{margin:1.25cm .75cm}
|
||
@media print{*{-webkit-box-shadow:none!important;box-shadow:none!important;text-shadow:none!important}
|
||
html{font-size:80%}
|
||
a{color:inherit!important;text-decoration:underline!important}
|
||
a.bare,a[href^="#"],a[href^="mailto:"]{text-decoration:none!important}
|
||
a[href^="http:"]:not(.bare)::after,a[href^="https:"]:not(.bare)::after{content:"(" attr(href) ")";display:inline-block;font-size:.875em;padding-left:.25em}
|
||
abbr[title]::after{content:" (" attr(title) ")"}
|
||
pre,blockquote,tr,img,object,svg{page-break-inside:avoid}
|
||
thead{display:table-header-group}
|
||
svg{max-width:100%}
|
||
p,blockquote,dt,td.content{font-size:1em;orphans:3;widows:3}
|
||
h2,h3,#toctitle,.sidebarblock>.content>.title{page-break-after:avoid}
|
||
#header,#content,#footnotes,#footer{max-width:none}
|
||
#toc,.sidebarblock,.exampleblock>.content{background:none!important}
|
||
#toc{border-bottom:1px solid #dddddf!important;padding-bottom:0!important}
|
||
body.book #header{text-align:center}
|
||
body.book #header>h1:first-child{border:0!important;margin:2.5em 0 1em}
|
||
body.book #header .details{border:0!important;display:block;padding:0!important}
|
||
body.book #header .details span:first-child{margin-left:0!important}
|
||
body.book #header .details br{display:block}
|
||
body.book #header .details br+span::before{content:none!important}
|
||
body.book #toc{border:0!important;text-align:left!important;padding:0!important;margin:0!important}
|
||
body.book #toc,body.book #preamble,body.book h1.sect0,body.book .sect1>h2{page-break-before:always}
|
||
.listingblock code[data-lang]::before{display:block}
|
||
#footer{padding:0 .9375em}
|
||
.hide-on-print{display:none!important}
|
||
.print-only{display:block!important}
|
||
.hide-for-print{display:none!important}
|
||
.show-for-print{display:inherit!important}}
|
||
@media print,amzn-kf8{#header>h1:first-child{margin-top:1.25rem}
|
||
.sect1{padding:0!important}
|
||
.sect1+.sect1{border:0}
|
||
#footer{background:none}
|
||
#footer-text{color:rgba(0,0,0,.6);font-size:.9em}}
|
||
@media amzn-kf8{#header,#content,#footnotes,#footer{padding:0}}
|
||
</style>
|
||
<style>
|
||
pre{ white-space:pre }
|
||
#header,#content,#footnotes,#footer {
|
||
margin-left:40px;
|
||
padding-right:60px;
|
||
max-width:none;
|
||
}
|
||
</style>
|
||
<style>.toc-current{font-weight: bold;} .toc-root{font-family: "Open Sans","DejaVu Sans",sans-serif;
|
||
font-size: 0.9em;} #content{display: flex; flex-direction: column; flex: 1 1 auto;}
|
||
.nav-footer{text-align: center; margin-top: auto;}
|
||
.nav-footer > p > a {white-space: nowrap;}</style>
|
||
</head>
|
||
<body id="wfe-from-userland" class="article">
|
||
<div id="header">
|
||
<h1>Linux Kernel Module Cheat</h1>
|
||
</div>
|
||
<div id="content">
|
||
<div class="sect5">
|
||
<h6 id="wfe-from-userland"><a class="anchor" href="#wfe-from-userland"></a><a class="link" href="#wfe-from-userland">33.10.3.1.2. WFE from userland</a></h6>
|
||
<div class="paragraph">
|
||
<p>WFE and SEV are usable from userland, and are part of an efficient spinlock implementation (which userland should arguably stay away from and rather use the <a href="futex-system-call.html">futex system call</a> which allow for non busy sleep instead), which maybe is not something that userland should ever tho and just stick to mutexes?</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>There is a control bit <code>SCTLR_EL1.nTWE</code> that determines if WFE is trapped or not, i.e.: is that bit is set, then it is trapped and EL0 execution raises an exception in EL1.</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>Linux v5.2.1 does not set <code>SCTLR_EL1.nTWE</code> however, tested with <a href="gem5-tracing.html">gem5 tracing</a> with <code>--trace ExecAll,Failts</code> and the <a href="dump-regs.html">dump_regs kernel module</a> in a full system simulation.</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>The kernel seems to setup nTWE at:</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>include/asm/sysreg.h</p>
|
||
</div>
|
||
<div class="literalblock">
|
||
<div class="content">
|
||
<pre>#define SCTLR_EL1_SET (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_SA |\
|
||
...
|
||
SCTLR_EL1_NTWE | SCTLR_ELx_IESB | SCTLR_EL1_SPAN |\</pre>
|
||
</div>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>and:</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>mm/proc.S</p>
|
||
</div>
|
||
<div class="literalblock">
|
||
<div class="content">
|
||
<pre> /*
|
||
* Prepare SCTLR
|
||
*/
|
||
mov_q x0, SCTLR_EL1_SET</pre>
|
||
</div>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>To reduce the number of instructions from our trace, first we boot, and then we restore a checkpoint after boot with <a href="gem5-restore-new-script.html">gem5 checkpoint restore and run a different script</a> with a restore command that runs <a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/arch/aarch64/freestanding/linux/wfe_wfe.S">userland/arch/aarch64/freestanding/linux/wfe_wfe.S</a>:</p>
|
||
</div>
|
||
<div class="literalblock">
|
||
<div class="content">
|
||
<pre>./run --arch aarch64 --emulator gem5 --gem5-worktree master --gem5-restore 1 --gem5-readfile 'arch/aarch64/freestanding/linux/wfe_wfe.out' --trace ExecAll,Faults,FmtFlag,Thread</pre>
|
||
</div>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>On the traces, we search for <code>wfe</code>, and there are just two hits, so they must be our instructions!</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>The traces then look like this at LKMC 777b7cbbd1d553baf2be9bc2075102be740054dd:</p>
|
||
</div>
|
||
<div class="literalblock">
|
||
<div class="content">
|
||
<pre>112285501668497000: Thread: system.cpu: suspend contextId 0
|
||
112285501668497000: ExecEnable: system.cpu: A0 T0 : 0x400078 : wfe : IntAlu : D=0x0000000000000000 flags=(IsSerializeAfter|IsNonSpeculative|IsQuiesce|IsUnverifiable)
|
||
112285501668497501: Thread: system.cpu: activate contextId 0
|
||
112285501668498000: Thread: system.cpu: suspend contextId 0
|
||
112285501668498000: ExecEnable: system.cpu: A0 T0 : 0x40007c : wfe : IntAlu : D=0x0000000000000000 flags=(IsSerializeAfter|IsNonSpeculative|IsQuiesce|IsUnverifiable)
|
||
112285501909320284: Thread: system.cpu: activate contextId 0
|
||
112285501909320500: Faults: IRQ: Invoking Fault (AArch64 target EL):IRQ cpsr:0x4003c5 PC:0x400080 elr:0x400080 newVec: 0xffffff8010082480
|
||
112285501909320500: ExecEnable: system.cpu: A0 T0 : @vectors+1152 : nop : IntAlu : flags=(IsNop)
|
||
112285501909321000: ExecEnable: system.cpu: A0 T0 : @vectors+1156 : nop : IntAlu : flags=(IsNop)
|
||
|
||
[more exception handler, no ERET here]
|
||
|
||
112285501923080500: ExecEnable: system.cpu: A0 T0 : @finish_ret_to_user+188 : ldr x30, [sp, #240] : MemRead : D=0x0000000000000000 A=0xffffff8010cb3fb0 flags=(IsInteger|IsMemRef|IsLoad)
|
||
112285501923081000: ExecEnable: system.cpu: A0 T0 : @finish_ret_to_user+192 : add sp, sp, #320 : IntAlu : D=0xffffff8010cb4000 flags=(IsInteger)
|
||
112285501923081500: ExecEnable: system.cpu: A0 T0 : 0xffffff8010084144 : eret : IntAlu : D=0x0000000000000001 flags=(IsControl|IsSerializeAfter|IsNonSpeculative|IsSquashAfter)
|
||
112285501923082000: ExecEnable: system.cpu: A0 T0 : 0x400080 : movz x0, #0, #0 : IntAlu : D=0x0000000000000000 flags=(IsInteger)
|
||
112285501923082500: ExecEnable: system.cpu: A0 T0 : 0x400084 : movz x8, #93, #0 : IntAlu : D=0x000000000000005d flags=(IsInteger)
|
||
112285501923083000: ExecEnable: system.cpu: A0 T0 : 0x400088 : svc #0x0 : IntAlu : flags=(IsSerializeAfter|IsNonSpeculative|IsSyscall)</pre>
|
||
</div>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>so we conclude that:</p>
|
||
</div>
|
||
<div class="ulist">
|
||
<ul>
|
||
<li>
|
||
<p>the second WFE made the CPU stop running instructions at time 112285501668498000 and PC 0x40007c</p>
|
||
</li>
|
||
<li>
|
||
<p>the next thing that happened a long time later (112285501909320500, while a following instruction would happen at 112285501668498000 + 1000) was an interrupt, presumably the <a href="arm-timer.html">ARM timer</a></p>
|
||
</li>
|
||
<li>
|
||
<p>after a few interrupt handler instructions, the first <a href="arm-svc-instruction.html">ERET</a> instruction exits the handler and comes back directly to the instruction after the WFE at PC 0x400080 == 0x40007c + 4</p>
|
||
</li>
|
||
<li>
|
||
<p>the execution of the interrupt handler woke up the core that was in WFE, and it now continues normal execution past the WFE</p>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>Therefore, a WFE in userland is treated much like a busy loop by the Linux kernel: the kernel does not seem to try and explicitly make up room for other processes as would happen on a futex.</p>
|
||
</div>
|
||
<div class="paragraph">
|
||
<p>The following test checks that SEV events don’t wake up a futexes, running forever in case of success. In <a href="gem5-syscall-emulation-multithreading.html">gem5 syscall emulation multithreading</a>, this is crucial to prevent deadlocks:</p>
|
||
</div>
|
||
<div class="ulist">
|
||
<ul>
|
||
<li>
|
||
<p><a href="https://github.com/cirosantilli/linux-kernel-module-cheat/blob/master/userland/arch/aarch64/inline_asm/futex_sev.cpp">userland/arch/aarch64/inline_asm/futex_sev.cpp</a></p>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
<div class="ulist">
|
||
<ul>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
<div class="paragraph nav-footer">
|
||
<p>← Previous: <a href="arm-wfe-global-monitor-events.html">ARM WFE global monitor events</a> | ↑ Up: <a href="arm-wfe-and-sev-instructions.html">ARM WFE and SEV instructions</a> | ⌂ Home: <a href="README.html">Linux Kernel Module Cheat</a> | Next: <a href="armv8-spinlock-pattern.html">ARMv8 spinlock pattern</a> →</p>
|
||
</div>
|
||
</div>
|
||
<script>
|
||
<!-- Google Analytics, AKA selling my soul to Google for some backlinks. -->
|
||
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
|
||
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
|
||
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
|
||
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
|
||
ga('create', 'UA-47867706-1', 'auto');
|
||
ga('send', 'pageview');
|
||
</script>
|
||
</body>
|
||
</html> |