ARMv7-A 那些事 - 7.栈回溯浅析
 2023.10.14    |      ARMv7-A    |     AilsonJack    |     暂无评论    |     54 views
By: AilsonJack
Date: 2023-10-14
个人博客: http://www.only2fire.com/
<meta charset="UTF-8"/><meta name="viewport" content="width=device-width initial-scale=1"/><link href="https://fonts.googleapis.com/css?family=Open+Sans:400italic,700italic,700,400&subset=latin,latin-ext" rel="stylesheet" type="text/css"/><style type="text/css">html {overflow-x: initial !important;}:root { --bg-color:#ffffff; --text-color:#333333; --select-text-bg-color:#B5D6FC; --select-text-font-color:auto; --monospace:"Lucida Console",Consolas,"Courier",monospace; --title-bar-height:20px; } .mac-os-11 { --title-bar-height:28px; } html { font-size: 14px; background-color: var(--bg-color); color: var(--text-color); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; -webkit-font-smoothing: antialiased; } h1, h2, h3, h4, h5 { white-space: pre-wrap; } body { margin: 0px; padding: 0px; height: auto; inset: 0px; font-size: 1rem; line-height: 1.42857; overflow-x: hidden; background: inherit; tab-size: 4; } iframe { margin: auto; } a.url { word-break: break-all; } a:active, a:hover { outline: 0px; } .in-text-selection, ::selection { text-shadow: none; background: var(--select-text-bg-color); color: var(--select-text-font-color); } #write { margin: 0px auto; height: auto; width: inherit; word-break: normal; overflow-wrap: break-word; position: relative; white-space: normal; overflow-x: visible; padding-top: 36px; } #write.first-line-indent p { text-indent: 2em; } #write.first-line-indent li p, #write.first-line-indent p * { text-indent: 0px; } #write.first-line-indent li { margin-left: 2em; } .for-image #write { padding-left: 8px; padding-right: 8px; } body.typora-export { padding-left: 30px; padding-right: 30px; } .typora-export .footnote-line, .typora-export li, .typora-export p { white-space: pre-wrap; } .typora-export .task-list-item input { pointer-events: none; } @media screen and (max-width: 500px) { body.typora-export { padding-left: 0px; padding-right: 0px; } #write { padding-left: 20px; padding-right: 20px; } } #write li >figure:last-child { margin-bottom: 0.5rem; } #write ol, #write ul { position: relative; } img { max-width: 100%; vertical-align: middle; image-orientation: from-image; } button, input, select, textarea { color: inherit; font: inherit; } input[type="checkbox"], input[type="radio"] { line-height: normal; padding: 0px; } *, ::after, ::before { box-sizing: border-box; } #write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p, #write pre { width: inherit; } #write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p { position: relative; } p { line-height: inherit; } h1, h2, h3, h4, h5, h6 { break-after: avoid-page; break-inside: avoid; orphans: 4; } p { orphans: 4; } h1 { font-size: 2rem; } h2 { font-size: 1.8rem; } h3 { font-size: 1.6rem; } h4 { font-size: 1.4rem; } h5 { font-size: 1.2rem; } h6 { font-size: 1rem; } .md-math-block, .md-rawblock, h1, h2, h3, h4, h5, h6, p { margin-top: 1rem; margin-bottom: 1rem; } .hidden { display: none; } .md-blockmeta { color: rgb(204, 204, 204); font-weight: 700; font-style: italic; } a { cursor: pointer; } sup.md-footnote { padding: 2px 4px; background-color: rgba(238, 238, 238, 0.7); color: rgb(85, 85, 85); border-radius: 4px; cursor: pointer; } sup.md-footnote a, sup.md-footnote a:hover { color: inherit; text-transform: inherit; text-decoration: inherit; } #write input[type="checkbox"] { cursor: pointer; width: inherit; height: inherit; } figure { overflow-x: auto; margin: 1.2em 0px; max-width: calc(100% + 16px); padding: 0px; } figure > table { margin: 0px; } thead, tr { break-inside: avoid; break-after: auto; } thead { display: table-header-group; } table { border-collapse: collapse; border-spacing: 0px; width: 100%; overflow: auto; break-inside: auto; text-align: left; } table.md-table td { min-width: 32px; } .CodeMirror-gutters { border-right: 0px; background-color: inherit; } .CodeMirror-linenumber { user-select: none; } .CodeMirror { text-align: left; } .CodeMirror-placeholder { opacity: 0.3; } .CodeMirror pre { padding: 0px 4px; } .CodeMirror-lines { padding: 0px; } div.hr:focus { cursor: none; } #write pre { white-space: pre-wrap; } #write.fences-no-line-wrapping pre { white-space: pre; } #write pre.ty-contain-cm { white-space: normal; } .CodeMirror-gutters { margin-right: 4px; } .md-fences { font-size: 0.9rem; display: block; break-inside: avoid; text-align: left; overflow: visible; white-space: pre; background: inherit; position: relative !important; } .md-fences-adv-panel { width: 100%; margin-top: 10px; text-align: center; padding-top: 0px; padding-bottom: 8px; overflow-x: auto; } #write .md-fences.mock-cm { white-space: pre-wrap; } .md-fences.md-fences-with-lineno { padding-left: 0px; } #write.fences-no-line-wrapping .md-fences.mock-cm { white-space: pre; overflow-x: auto; } .md-fences.mock-cm.md-fences-with-lineno { padding-left: 8px; } .CodeMirror-line, twitterwidget { break-inside: avoid; } svg { break-inside: avoid; } .footnotes { opacity: 0.8; font-size: 0.9rem; margin-top: 1em; margin-bottom: 1em; } .footnotes + .footnotes { margin-top: 0px; } .md-reset { margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: top; background: 0px 0px; text-decoration: none; text-shadow: none; float: none; position: static; width: auto; height: auto; white-space: nowrap; cursor: inherit; -webkit-tap-highlight-color: transparent; line-height: normal; font-weight: 400; text-align: left; box-sizing: content-box; direction: ltr; } li div { padding-top: 0px; } blockquote { margin: 1rem 0px; } li .mathjax-block, li p { margin: 0.5rem 0px; } li blockquote { margin: 1rem 0px; } li { margin: 0px; position: relative; } blockquote > :last-child { margin-bottom: 0px; } blockquote > :first-child, li > :first-child { margin-top: 0px; } .footnotes-area { color: rgb(136, 136, 136); margin-top: 0.714rem; padding-bottom: 0.143rem; white-space: normal; } #write .footnote-line { white-space: pre-wrap; } @media print { body, html { border: 1px solid transparent; height: 99%; break-after: avoid; break-before: avoid; font-variant-ligatures: no-common-ligatures; } #write { margin-top: 0px; border-color: transparent !important; padding-top: 0px !important; padding-bottom: 0px !important; } .typora-export * { -webkit-print-color-adjust: exact; } .typora-export #write { break-after: avoid; } .typora-export #write::after { height: 0px; } .is-mac table { break-inside: avoid; } #write > p:nth-child(1) { margin-top: 0px; } .typora-export-show-outline .typora-export-sidebar { display: none; } figure { overflow-x: visible; } } .footnote-line { margin-top: 0.714em; font-size: 0.7em; } a img, img a { cursor: pointer; } pre.md-meta-block { font-size: 0.8rem; min-height: 0.8rem; white-space: pre-wrap; background: rgb(204, 204, 204); display: block; overflow-x: hidden; } p > .md-image:only-child:not(.md-img-error) img, p > img:only-child { display: block; margin: auto; } #write.first-line-indent p > .md-image:only-child:not(.md-img-error) img { left: -2em; position: relative; } p > .md-image:only-child { display: inline-block; width: 100%; } #write .MathJax_Display { margin: 0.8em 0px 0px; } .md-math-block { width: 100%; } .md-math-block:not(:empty)::after { display: none; } .MathJax_ref { fill: currentcolor; } [contenteditable="true"]:active, [contenteditable="true"]:focus, [contenteditable="false"]:active, [contenteditable="false"]:focus { outline: 0px; box-shadow: none; } .md-task-list-item { position: relative; list-style-type: none; } .task-list-item.md-task-list-item { padding-left: 0px; } .md-task-list-item > input { position: absolute; top: 0px; left: 0px; margin-left: -1.2em; margin-top: calc(1em - 10px); border: none; } .math { font-size: 1rem; } .md-toc { min-height: 3.58rem; position: relative; font-size: 0.9rem; border-radius: 10px; } .md-toc-content { position: relative; margin-left: 0px; } .md-toc-content::after, .md-toc::after { display: none; } .md-toc-item { display: block; color: rgb(65, 131, 196); } .md-toc-item a { text-decoration: none; } .md-toc-inner:hover { text-decoration: underline; } .md-toc-inner { display: inline-block; cursor: pointer; } .md-toc-h1 .md-toc-inner { margin-left: 0px; font-weight: 700; } .md-toc-h2 .md-toc-inner { margin-left: 2em; } .md-toc-h3 .md-toc-inner { margin-left: 4em; } .md-toc-h4 .md-toc-inner { margin-left: 6em; } .md-toc-h5 .md-toc-inner { margin-left: 8em; } .md-toc-h6 .md-toc-inner { margin-left: 10em; } @media screen and (max-width: 48em) { .md-toc-h3 .md-toc-inner { margin-left: 3.5em; } .md-toc-h4 .md-toc-inner { margin-left: 5em; } .md-toc-h5 .md-toc-inner { margin-left: 6.5em; } .md-toc-h6 .md-toc-inner { margin-left: 8em; } } a.md-toc-inner { font-size: inherit; font-style: inherit; font-weight: inherit; line-height: inherit; } .footnote-line a:not(.reversefootnote) { color: inherit; } .reversefootnote { font-family: ui-monospace, sans-serif; } .md-attr { display: none; } .md-fn-count::after { content: "."; } code, pre, samp, tt { font-family: var(--monospace); } kbd { margin: 0px 0.1em; padding: 0.1em 0.6em; font-size: 0.8em; color: rgb(36, 39, 41); background: rgb(255, 255, 255); border: 1px solid rgb(173, 179, 185); border-radius: 3px; box-shadow: rgba(12, 13, 14, 0.2) 0px 1px 0px, rgb(255, 255, 255) 0px 0px 0px 2px inset; white-space: nowrap; vertical-align: middle; } .md-comment { color: rgb(162, 127, 3); opacity: 0.6; font-family: var(--monospace); } code { text-align: left; vertical-align: initial; } a.md-print-anchor { white-space: pre !important; border-width: initial !important; border-style: none !important; border-color: initial !important; display: inline-block !important; position: absolute !important; width: 1px !important; right: 0px !important; outline: 0px !important; background: 0px 0px !important; text-decoration: initial !important; text-shadow: initial !important; } .os-windows.monocolor-emoji .md-emoji { font-family: "Segoe UI Symbol", sans-serif; } .md-diagram-panel > svg { max-width: 100%; } [lang="flow"] svg, [lang="mermaid"] svg { max-width: 100%; height: auto; } [lang="mermaid"] .node text { font-size: 1rem; } table tr th { border-bottom: 0px; } video { max-width: 100%; display: block; margin: 0px auto; } iframe { max-width: 100%; width: 100%; border: none; } .highlight td, .highlight tr { border: 0px; } mark { background: rgb(255, 255, 0); color: rgb(0, 0, 0); } .md-html-inline .md-plain, .md-html-inline strong, mark .md-inline-math, mark strong { color: inherit; } .md-expand mark .md-meta { opacity: 0.3 !important; } mark .md-meta { color: rgb(0, 0, 0); } @media print { .typora-export h1, .typora-export h2, .typora-export h3, .typora-export h4, .typora-export h5, .typora-export h6 { break-inside: avoid; } } .md-diagram-panel .messageText { stroke: none !important; } .md-diagram-panel .start-state { fill: var(--node-fill); } .md-diagram-panel .edgeLabel rect { opacity: 1 !important; } .md-fences.md-fences-math { font-size: 1em; } .md-fences-advanced:not(.md-focus) { padding: 0px; white-space: nowrap; border: 0px; } .md-fences-advanced:not(.md-focus) { background: inherit; } .typora-export-show-outline .typora-export-content { max-width: 1440px; margin: auto; display: flex; flex-direction: row; } .typora-export-sidebar { width: 300px; font-size: 0.8rem; margin-top: 80px; margin-right: 18px; } .typora-export-show-outline #write { --webkit-flex:2; flex: 2 1 0%; } .typora-export-sidebar .outline-content { position: fixed; top: 0px; max-height: 100%; overflow: hidden auto; padding-bottom: 30px; padding-top: 60px; width: 300px; } @media screen and (max-width: 1024px) { .typora-export-sidebar, .typora-export-sidebar .outline-content { width: 240px; } } @media screen and (max-width: 800px) { .typora-export-sidebar { display: none; } } .outline-content li, .outline-content ul { margin-left: 0px; margin-right: 0px; padding-left: 0px; padding-right: 0px; list-style: none; overflow-wrap: anywhere; } .outline-content ul { margin-top: 0px; margin-bottom: 0px; } .outline-content strong { font-weight: 400; } .outline-expander { width: 1rem; height: 1.42857rem; position: relative; display: table-cell; vertical-align: middle; cursor: pointer; padding-left: 4px; } .outline-expander::before { content: ""; position: relative; font-family: Ionicons; display: inline-block; font-size: 8px; vertical-align: middle; } .outline-item { padding-top: 3px; padding-bottom: 3px; cursor: pointer; } .outline-expander:hover::before { content: ""; } .outline-h1 > .outline-item { padding-left: 0px; } .outline-h2 > .outline-item { padding-left: 1em; } .outline-h3 > .outline-item { padding-left: 2em; } .outline-h4 > .outline-item { padding-left: 3em; } .outline-h5 > .outline-item { padding-left: 4em; } .outline-h6 > .outline-item { padding-left: 5em; } .outline-label { cursor: pointer; display: table-cell; vertical-align: middle; text-decoration: none; color: inherit; } .outline-label:hover { text-decoration: underline; } .outline-item:hover { border-color: rgb(245, 245, 245); background-color: var(--item-hover-bg-color); } .outline-item:hover { margin-left: -28px; margin-right: -28px; border-left: 28px solid transparent; border-right: 28px solid transparent; } .outline-item-single .outline-expander::before, .outline-item-single .outline-expander:hover::before { display: none; } .outline-item-open > .outline-item > .outline-expander::before { content: ""; } .outline-children { display: none; } .info-panel-tab-wrapper { display: none; } .outline-item-open > .outline-children { display: block; } .typora-export .outline-item { padding-top: 1px; padding-bottom: 1px; } .typora-export .outline-item:hover { margin-right: -8px; border-right: 8px solid transparent; } .typora-export .outline-expander::before { content: "+"; font-family: inherit; top: -1px; } .typora-export .outline-expander:hover::before, .typora-export .outline-item-open > .outline-item > .outline-expander::before { content: "−"; } .typora-export-collapse-outline .outline-children { display: none; } .typora-export-collapse-outline .outline-item-open > .outline-children, .typora-export-no-collapse-outline .outline-children { display: block; } .typora-export-no-collapse-outline .outline-expander::before { content: "" !important; } .typora-export-show-outline .outline-item-active > .outline-item .outline-label { font-weight: 700; } .md-inline-math-container mjx-container { zoom: 0.95; } mjx-container { break-inside: avoid; } .CodeMirror { height: auto; } .CodeMirror.cm-s-inner { background: inherit; } .CodeMirror-scroll { overflow: auto hidden; z-index: 3; } .CodeMirror-gutter-filler, .CodeMirror-scrollbar-filler { background-color: rgb(255, 255, 255); } .CodeMirror-gutters { border-right: 1px solid rgb(221, 221, 221); background: inherit; white-space: nowrap; } .CodeMirror-linenumber { padding: 0px 3px 0px 5px; text-align: right; color: rgb(153, 153, 153); } .cm-s-inner .cm-keyword { color: rgb(119, 0, 136); } .cm-s-inner .cm-atom, .cm-s-inner.cm-atom { color: rgb(34, 17, 153); } .cm-s-inner .cm-number { color: rgb(17, 102, 68); } .cm-s-inner .cm-def { color: rgb(0, 0, 255); } .cm-s-inner .cm-variable { color: rgb(0, 0, 0); } .cm-s-inner .cm-variable-2 { color: rgb(0, 85, 170); } .cm-s-inner .cm-variable-3 { color: rgb(0, 136, 85); } .cm-s-inner .cm-string { color: rgb(170, 17, 17); } .cm-s-inner .cm-property { color: rgb(0, 0, 0); } .cm-s-inner .cm-operator { color: rgb(152, 26, 26); } .cm-s-inner .cm-comment, .cm-s-inner.cm-comment { color: rgb(170, 85, 0); } .cm-s-inner .cm-string-2 { color: rgb(255, 85, 0); } .cm-s-inner .cm-meta { color: rgb(85, 85, 85); } .cm-s-inner .cm-qualifier { color: rgb(85, 85, 85); } .cm-s-inner .cm-builtin { color: rgb(51, 0, 170); } .cm-s-inner .cm-bracket { color: rgb(153, 153, 119); } .cm-s-inner .cm-tag { color: rgb(17, 119, 0); } .cm-s-inner .cm-attribute { color: rgb(0, 0, 204); } .cm-s-inner .cm-header, .cm-s-inner.cm-header { color: rgb(0, 0, 255); } .cm-s-inner .cm-quote, .cm-s-inner.cm-quote { color: rgb(0, 153, 0); } .cm-s-inner .cm-hr, .cm-s-inner.cm-hr { color: rgb(153, 153, 153); } .cm-s-inner .cm-link, .cm-s-inner.cm-link { color: rgb(0, 0, 204); } .cm-negative { color: rgb(221, 68, 68); } .cm-positive { color: rgb(34, 153, 34); } .cm-header, .cm-strong { font-weight: 700; } .cm-del { text-decoration: line-through; } .cm-em { font-style: italic; } .cm-link { text-decoration: underline; } .cm-error { color: red; } .cm-invalidchar { color: red; } .cm-constant { color: rgb(38, 139, 210); } .cm-defined { color: rgb(181, 137, 0); } div.CodeMirror span.CodeMirror-matchingbracket { color: rgb(0, 255, 0); } div.CodeMirror span.CodeMirror-nonmatchingbracket { color: rgb(255, 34, 34); } .cm-s-inner .CodeMirror-activeline-background { background: inherit; } .CodeMirror { position: relative; overflow: hidden; } .CodeMirror-scroll { height: 100%; outline: 0px; position: relative; box-sizing: content-box; background: inherit; } .CodeMirror-sizer { position: relative; } .CodeMirror-gutter-filler, .CodeMirror-hscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-vscrollbar { position: absolute; z-index: 6; display: none; outline: 0px; } .CodeMirror-vscrollbar { right: 0px; top: 0px; overflow: hidden; } .CodeMirror-hscrollbar { bottom: 0px; left: 0px; overflow: auto hidden; } .CodeMirror-scrollbar-filler { right: 0px; bottom: 0px; } .CodeMirror-gutter-filler { left: 0px; bottom: 0px; } .CodeMirror-gutters { position: absolute; left: 0px; top: 0px; padding-bottom: 10px; z-index: 3; overflow-y: hidden; } .CodeMirror-gutter { white-space: normal; height: 100%; box-sizing: content-box; padding-bottom: 30px; margin-bottom: -32px; display: inline-block; } .CodeMirror-gutter-wrapper { position: absolute; z-index: 4; background: 0px 0px !important; border: none !important; } .CodeMirror-gutter-background { position: absolute; top: 0px; bottom: 0px; z-index: 4; } .CodeMirror-gutter-elt { position: absolute; cursor: default; z-index: 4; } .CodeMirror-lines { cursor: text; } .CodeMirror pre { border-radius: 0px; border-width: 0px; background: 0px 0px; font-family: inherit; font-size: inherit; margin: 0px; white-space: pre; overflow-wrap: normal; color: inherit; z-index: 2; position: relative; overflow: visible; } .CodeMirror-wrap pre { overflow-wrap: break-word; white-space: pre-wrap; word-break: normal; } .CodeMirror-code pre { border-right: 30px solid transparent; width: fit-content; } .CodeMirror-wrap .CodeMirror-code pre { border-right: none; width: auto; } .CodeMirror-linebackground { position: absolute; inset: 0px; z-index: 0; } .CodeMirror-linewidget { position: relative; z-index: 2; overflow: auto; } .CodeMirror-wrap .CodeMirror-scroll { overflow-x: hidden; } .CodeMirror-measure { position: absolute; width: 100%; height: 0px; overflow: hidden; visibility: hidden; } .CodeMirror-measure pre { position: static; } .CodeMirror div.CodeMirror-cursor { position: absolute; visibility: hidden; border-right: none; width: 0px; } .CodeMirror div.CodeMirror-cursor { visibility: hidden; } .CodeMirror-focused div.CodeMirror-cursor { visibility: inherit; } .cm-searching { background: rgba(255, 255, 0, 0.4); } span.cm-underlined { text-decoration: underline; } span.cm-strikethrough { text-decoration: line-through; } .cm-tw-syntaxerror { color: rgb(255, 255, 255); background-color: rgb(153, 0, 0); } .cm-tw-deleted { text-decoration: line-through; } .cm-tw-header5 { font-weight: 700; } .cm-tw-listitem:first-child { padding-left: 10px; } .cm-tw-box { border-style: solid; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-color: inherit; border-top-width: 0px !important; } .cm-tw-underline { text-decoration: underline; } @media print { .CodeMirror div.CodeMirror-cursor { visibility: hidden; } } :root { --side-bar-bg-color: #fafafa; --control-text-color: #777; } @include-when-export url(https://fonts.googleapis.com/css?family=Open+Sans:400italic,700italic,700,400&subset=latin,latin-ext); /* open-sans-regular - latin-ext_latin */ /* open-sans-italic - latin-ext_latin */ /* open-sans-700 - latin-ext_latin */ /* open-sans-700italic - latin-ext_latin */ html { font-size: 16px; -webkit-font-smoothing: antialiased; } body { font-family: "Open Sans","Clear Sans", "Helvetica Neue", Helvetica, Arial, 'Segoe UI Emoji', sans-serif; color: rgb(51, 51, 51); line-height: 1.6; } #write { max-width: 860px; margin: 0 auto; padding: 30px; padding-bottom: 100px; } @media only screen and (min-width: 1400px) { #write { max-width: 1024px; } } @media only screen and (min-width: 1800px) { #write { max-width: 1200px; } } #write > ul:first-child, #write > ol:first-child{ margin-top: 30px; } a { color: #4183C4; } h1, h2, h3, h4, h5, h6 { position: relative; margin-top: 1rem; margin-bottom: 1rem; font-weight: bold; line-height: 1.4; cursor: text; } h1:hover a.anchor, h2:hover a.anchor, h3:hover a.anchor, h4:hover a.anchor, h5:hover a.anchor, h6:hover a.anchor { text-decoration: none; } h1 tt, h1 code { font-size: inherit; } h2 tt, h2 code { font-size: inherit; } h3 tt, h3 code { font-size: inherit; } h4 tt, h4 code { font-size: inherit; } h5 tt, h5 code { font-size: inherit; } h6 tt, h6 code { font-size: inherit; } h1 { font-size: 2.25em; line-height: 1.2; border-bottom: 1px solid #eee; } h2 { font-size: 1.75em; line-height: 1.225; border-bottom: 1px solid #eee; } /*@media print { .typora-export h1, .typora-export h2 { border-bottom: none; padding-bottom: initial; } .typora-export h1::after, .typora-export h2::after { content: ""; display: block; height: 100px; margin-top: -96px; border-top: 1px solid #eee; } }*/ h3 { font-size: 1.5em; line-height: 1.43; } h4 { font-size: 1.25em; } h5 { font-size: 1em; } h6 { font-size: 1em; color: #777; } p, blockquote, ul, ol, dl, table{ margin: 0.8em 0; } li>ol, li>ul { margin: 0 0; } hr { height: 2px; padding: 0; margin: 16px 0; background-color: #e7e7e7; border: 0 none; overflow: hidden; box-sizing: content-box; } li p.first { display: inline-block; } ul, ol { padding-left: 30px; } ul:first-child, ol:first-child { margin-top: 0; } ul:last-child, ol:last-child { margin-bottom: 0; } blockquote { border-left: 4px solid #dfe2e5; padding: 0 15px; color: #777777; } blockquote blockquote { padding-right: 0; } table { padding: 0; word-break: initial; } table tr { border: 1px solid #dfe2e5; margin: 0; padding: 0; } table tr:nth-child(2n), thead { background-color: #f8f8f8; } table th { font-weight: bold; border: 1px solid #dfe2e5; border-bottom: 0; margin: 0; padding: 6px 13px; } table td { border: 1px solid #dfe2e5; margin: 0; padding: 6px 13px; } table th:first-child, table td:first-child { margin-top: 0; } table th:last-child, table td:last-child { margin-bottom: 0; } .CodeMirror-lines { padding-left: 4px; } .code-tooltip { box-shadow: 0 1px 1px 0 rgba(0,28,36,.3); border-top: 1px solid #eef2f2; } .md-fences, code, tt { border: 1px solid #e7eaed; background-color: #f8f8f8; border-radius: 3px; padding: 0; padding: 2px 4px 0px 4px; font-size: 0.9em; } code { background-color: #f3f4f4; padding: 0 2px 0 2px; } .md-fences { margin-bottom: 15px; margin-top: 15px; padding-top: 8px; padding-bottom: 6px; } .md-task-list-item > input { margin-left: -1.3em; } @media print { html { font-size: 13px; } pre { page-break-inside: avoid; word-wrap: break-word; } } .md-fences { background-color: #f8f8f8; } #write pre.md-meta-block { padding: 1rem; font-size: 85%; line-height: 1.45; background-color: #f7f7f7; border: 0; border-radius: 3px; color: #777777; margin-top: 0 !important; } .mathjax-block>.code-tooltip { bottom: .375rem; } .md-mathjax-midline { background: #fafafa; } #write>h3.md-focus:before{ left: -1.5625rem; top: .375rem; } #write>h4.md-focus:before{ left: -1.5625rem; top: .285714286rem; } #write>h5.md-focus:before{ left: -1.5625rem; top: .285714286rem; } #write>h6.md-focus:before{ left: -1.5625rem; top: .285714286rem; } .md-image>.md-meta { /*border: 1px solid #ddd;*/ border-radius: 3px; padding: 2px 0px 0px 4px; font-size: 0.9em; color: inherit; } .md-tag { color: #a7a7a7; opacity: 1; } .md-toc { margin-top:20px; padding-bottom:20px; } .sidebar-tabs { border-bottom: none; } #typora-quick-open { border: 1px solid #ddd; background-color: #f8f8f8; } #typora-quick-open-item { background-color: #FAFAFA; border-color: #FEFEFE #e5e5e5 #e5e5e5 #eee; border-style: solid; border-width: 1px; } /** focus mode */ .on-focus-mode blockquote { border-left-color: rgba(85, 85, 85, 0.12); } header, .context-menu, .megamenu-content, footer{ font-family: "Segoe UI", "Arial", sans-serif; } .file-node-content:hover .file-node-icon, .file-node-content:hover .file-node-open-state{ visibility: visible; } .mac-seamless-mode #typora-sidebar { background-color: #fafafa; background-color: var(--side-bar-bg-color); } .md-lang { color: #b4654d; } /*.html-for-mac { --item-hover-bg-color: #E6F0FE; }*/ #md-notification .btn { border: 0; } .dropdown-menu .divider { border-color: #e5e5e5; opacity: 0.4; } .ty-preferences .window-content { background-color: #fafafa; } .ty-preferences .nav-group-item.active { color: white; background: #999; } .menu-item-container a.menu-style-btn { background-color: #f5f8fa; background-image: linear-gradient( 180deg , hsla(0, 0%, 100%, 0.8), hsla(0, 0%, 100%, 0)); }</style><title>ARMv7-A 那些事 - 7.栈回溯浅析</title><p>在嵌入式开发过程中,经常需要对代码进行调试来解决各种各样的问题,常用的调试手段有:</p><p>(1)、开发环境搭配硬件仿真器进行在线调试。优点:调试过程中能够清楚的知道各个寄存器的值以及各个变量的值,程序的执行流程也能够一目了然。缺点:板卡需要引出硬件仿真器的连接口,并且需要购买硬件仿真器。</p><p>(2)、通过调试串口打印信息梳理程序的执行流程,结合代码分析问题产生的原因。优点:足够简单,通过增加较多的打印信息来分析问题出现的位置,再结合代码分析问题产生的原因。缺点:没法准确的定位问题产生的位置和原因。</p><p>(3)、在应用或者操作系统死机的时候,根据操作系统输出的异常栈信息进行分析,再结合镜像或者应用的反汇编代码进行定位。通常这种方法和方法(2)结合使用。</p><p>本文主要简单的讲讲栈回溯,对于以后去理解操作系统的异常栈处理打个基础吧。</p><p>ARM处理器的栈回溯主要有两种方式:一种是基于栈帧寄存器(FP)的栈回溯,另一种是unwind形式的栈回溯。本文主要讲讲基于栈帧寄存器(FP)的栈回溯。</p><h2 id="栈回溯相关寄存器">栈回溯相关寄存器</h2><p>在栈回溯过程中,主要涉及如下寄存器:</p><p>R15:又叫程序计数器(Program Counter)PC,PC主要用于存放CPU取指的地址。</p><p>R14:又叫链接寄存器(Link register)LR,LR主要用于存放函数的返回地址,即当函数返回时,知道自己该回到哪儿去继续运行。</p><p>R13:又叫堆栈指针寄存器(Stack pointer)SP,SP通常用于保存堆栈地址,在使用入栈和出栈指令时,SP中的堆栈地址会自动的更新。</p><p>R12:又叫内部过程调用暂存寄存器(Intra-Procedure-call scratch register)IP,主要用于暂存SP。</p><p>R11:又叫帧指针寄存器(Frame pointer)FP,通常指向一个函数的栈帧底部,表示一个函数栈的开始位置。</p><h2 id="arm栈帧结构">ARM栈帧结构</h2><p>依据AAPCS (ARM Archtecture Procedure Call Standard)规范,当调用子函数时,子函数一开始的代码总是会执行压栈操作来保留父函数的相关信息,压栈步骤示例如下所示:</p><pre class="md-fences md-end-block ty-contain-cm modeLoaded md-focus" spellcheck="false" lang="c">mov&nbsp;&nbsp;&nbsp;&nbsp;ip,&nbsp;sp push&nbsp;{fp,&nbsp;ip,&nbsp;lr,&nbsp;pc} sub&nbsp;&nbsp;&nbsp;&nbsp;fp,&nbsp;ip,&nbsp;#4 sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;sp,&nbsp;#16 ...</pre><p>每个函数都有自己的栈空间,这一部分称为栈帧。栈帧在函数被调用的时候创建,在函数返回后销毁。每个函数的栈帧是由SP寄存器和FP寄存器来界定的,ARM栈帧结构典型示意图如下所示:</p><p style="text-align:center"><img src="/uploads/AilsonJack/2023.10.14/112414860569798.png" onclick="preview_image(&#39;/uploads/AilsonJack/2023.10.14/112414860569798.png&#39;)"/></p><p>上图描述的栈帧,main函数和func1函数的示意代码如下:</p><pre class="brush:cpp;toolbar:false;" spellcheck="false" lang="c" style="break-inside: unset;">int&nbsp;func1(int&nbsp;p1,&nbsp;int&nbsp;p2,&nbsp;int&nbsp;p3,&nbsp;int&nbsp;p4,&nbsp;int&nbsp;p5) { &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;i; &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;j; &nbsp;&nbsp;&nbsp;&nbsp;i&nbsp;=&nbsp;0xf3; &nbsp;&nbsp;&nbsp;&nbsp;j&nbsp;=&nbsp;0xf6; &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;0; } int&nbsp;main(int&nbsp;argc,&nbsp;char&nbsp;*argv[]) { &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;i; &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;j; &nbsp;&nbsp;&nbsp;&nbsp;i&nbsp;=&nbsp;0x33; &nbsp;&nbsp;&nbsp;&nbsp;j&nbsp;=&nbsp;0x66; &nbsp;&nbsp;&nbsp;&nbsp;func1(0xa1,&nbsp;0xa2,&nbsp;0xa3,&nbsp;0xa4,&nbsp;0xa5); &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;0; }</pre><p>每个函数的栈帧中都会保存调用该函数之前的PC、LR、SP、FP寄存器的值;如果函数具有参数并且函数内部使用了局部变量,那么函数栈帧中也会保存函数的参数和局部变量;如果被调用的子函数参数过多,那么多余的参数会通过父函数的栈进行传递。比如func1函数的参数p5通过main函数的栈帧进行传递的。(注:编译器的版本不同,函数栈帧中参数和局部变量的压栈顺序可能不同,PC,LR,SP和FP这4个寄存器的压栈顺序一般是固定的)</p><p>函数栈帧中的PC和LR均指向代码段,PC表示执行入栈指令时CPU正在取指的地址,LR表示当前函数返回后继续执行的地址。</p><h2 id="栈回溯原理">栈回溯原理</h2><p>在栈回溯的过程中,我们主要利用FP寄存器进行栈回溯。通过FP就可以知道当前函数的栈底,从而可以找到存储在栈帧中的LR寄存器的数据,这个数据就是函数的返回地址。同时也可以找到保存在函数栈帧中的上一级函数FP的数据,这个数据指向了上一级函数的栈底,按照同样的方法可以找出上一级函数栈帧中存储的LR和FP数据,就知道哪个函数调用了上一级函数以及这个函数的栈底地址。这就是栈回溯的流程,整个流程以FP为核心,依次找出每个函数栈帧中存储的LR和FP数据,计算出函数返回地址和上一级函数栈底地址,从而找出每一级函数调用关系。</p><h2 id="栈回溯编译选项">栈回溯编译选项</h2><p>当gcc的编译选项带有<code>-mapcs-frame</code>时,编译出来的代码能够将PC,LR,SP和FP寄存器的值压入函数的栈帧中。默认情况下gcc的编译选项为<code>-mno-apcs-frame</code>,此时编译出来的代码不一定会将PC,LR,SP和FP这四个寄存器的值压入函数的栈帧中,可能只会将LR和FP寄存器的值压入函数的栈帧中。关于<code>-mapcs-frame</code>选项,gcc的手册描述如下:</p><pre class="md-fences md-end-block ty-contain-cm modeLoaded" spellcheck="false" lang="">Generate&nbsp;a&nbsp;stack&nbsp;frame&nbsp;that&nbsp;is&nbsp;compliant&nbsp;with&nbsp;the&nbsp;ARM&nbsp;Procedure&nbsp;Call&nbsp;Standard&nbsp;for&nbsp;all&nbsp; functions,&nbsp;even&nbsp;if&nbsp;this&nbsp;is&nbsp;not&nbsp;strictly&nbsp;necessary&nbsp;for&nbsp;correct&nbsp;execution&nbsp;of&nbsp;the&nbsp;code.&nbsp; Specifying&nbsp;‘-fomit-frame-pointer’&nbsp;with&nbsp;this&nbsp;option&nbsp;causes&nbsp;the&nbsp;stack&nbsp;frames&nbsp;not&nbsp;to&nbsp;be&nbsp; generated&nbsp;for&nbsp;leaf&nbsp;functions.&nbsp;The&nbsp;default&nbsp;is&nbsp;‘-mno-apcs-frame’. This&nbsp;option&nbsp;is&nbsp;deprecated.</pre><p>我这里使用的gcc信息如下:</p><pre class="md-fences md-end-block ty-contain-cm modeLoaded" spellcheck="false" lang="">$&nbsp;arm-none-eabi-gcc&nbsp;-v ... gcc&nbsp;version&nbsp;10.3.1&nbsp;20210824&nbsp;(release)&nbsp;(GNU&nbsp;Arm&nbsp;Embedded&nbsp;Toolchain&nbsp;10.3-2021.10)</pre><p>虽然gcc手册上说<code>-mapcs-frame</code>选项被废弃了,但是只有添加了该选项,编译出来的代码才会将PC,LR,SP和FP寄存器的值压入函数的栈帧中。</p><p>我这里编译代码仍然使用<code>-mapcs-frame</code>选项,有知道该选项对应的新的栈帧配置选项的兄弟可以告知我一下。</p><h2 id="栈回溯示例">栈回溯示例</h2><p>根据前面的内容,这里简单的写了一个栈回溯的示例,函数调用流程为:<code>main -&gt; test_a -&gt; test_b -&gt; test_c</code>。</p><p>函数的源代码如下:</p><pre class="brush:cpp;toolbar:false;" spellcheck="false" lang="c" style="break-inside: unset;">int&nbsp;test_a(int&nbsp;arg0,&nbsp;int&nbsp;arg1,&nbsp;int&nbsp;arg2,&nbsp;int&nbsp;arg3,&nbsp;int&nbsp;arg4) { &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;a; &nbsp;&nbsp;&nbsp;&nbsp;a&nbsp;=&nbsp;0xff11; &nbsp;&nbsp;&nbsp;&nbsp;test_b(0xbb00); &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;a; } int&nbsp;test_b(int&nbsp;arg0) { &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;b; &nbsp;&nbsp;&nbsp;&nbsp;b&nbsp;=&nbsp;0xff22; &nbsp;&nbsp;&nbsp;&nbsp;test_c(0xcc00); &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;b; } int&nbsp;test_c(int&nbsp;arg0) { &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;c; &nbsp;&nbsp;&nbsp;&nbsp;c&nbsp;=&nbsp;0xff33; &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;c; } int&nbsp;main(void) { &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;val; &nbsp;&nbsp;&nbsp;&nbsp;val&nbsp;=&nbsp;0xff00; &nbsp;&nbsp;&nbsp;&nbsp;test_a(0xaa00,&nbsp;0xaa11,&nbsp;0xaa22,&nbsp;0xaa33,&nbsp;0xaa44); &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;0; }</pre><p>上述函数的反汇编内容如下:</p><pre class="md-fences md-end-block ty-contain-cm modeLoaded" spellcheck="false" lang="c" style="break-inside: unset;">80002164&nbsp;&lt;test_a&gt;: int&nbsp;test_a(int&nbsp;arg0,&nbsp;int&nbsp;arg1,&nbsp;int&nbsp;arg2,&nbsp;int&nbsp;arg3,&nbsp;int&nbsp;arg4) { 80002164:&nbsp;&nbsp;&nbsp;&nbsp;e1a0c00d&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;ip,&nbsp;sp 80002168:&nbsp;&nbsp;&nbsp;&nbsp;e92dd800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;push&nbsp;&nbsp;&nbsp;&nbsp;{fp,&nbsp;ip,&nbsp;lr,&nbsp;pc} 8000216c:&nbsp;&nbsp;&nbsp;&nbsp;e24cb004&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;fp,&nbsp;ip,&nbsp;#4 80002170:&nbsp;&nbsp;&nbsp;&nbsp;e24dd018&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;sp,&nbsp;#24 80002174:&nbsp;&nbsp;&nbsp;&nbsp;e50b0018&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;[fp,&nbsp;#-24]&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xffffffe8 80002178:&nbsp;&nbsp;&nbsp;&nbsp;e50b101c&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r1,&nbsp;[fp,&nbsp;#-28]&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xffffffe4 8000217c:&nbsp;&nbsp;&nbsp;&nbsp;e50b2020&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r2,&nbsp;[fp,&nbsp;#-32]&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xffffffe0 80002180:&nbsp;&nbsp;&nbsp;&nbsp;e50b3024&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-36]&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xffffffdc &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;a; &nbsp;&nbsp;&nbsp;&nbsp;a&nbsp;=&nbsp;0xff11; 80002184:&nbsp;&nbsp;&nbsp;&nbsp;e30f3f11&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#65297&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xff11 80002188:&nbsp;&nbsp;&nbsp;&nbsp;e50b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] &nbsp;&nbsp;&nbsp;&nbsp;test_b(0xbb00); 8000218c:&nbsp;&nbsp;&nbsp;&nbsp;e3a00cbb&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;#47872&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xbb00 80002190:&nbsp;&nbsp;&nbsp;&nbsp;eb000003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;bl&nbsp;&nbsp;&nbsp;&nbsp;800021a4&nbsp;&lt;test_b&gt; &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;a; 80002194:&nbsp;&nbsp;&nbsp;&nbsp;e51b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldr&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] } 80002198:&nbsp;&nbsp;&nbsp;&nbsp;e1a00003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;r3 8000219c:&nbsp;&nbsp;&nbsp;&nbsp;e24bd00c&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;fp,&nbsp;#12 800021a0:&nbsp;&nbsp;&nbsp;&nbsp;e89da800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldm&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;{fp,&nbsp;sp,&nbsp;pc} 800021a4&nbsp;&lt;test_b&gt;: int&nbsp;test_b(int&nbsp;arg0) { 800021a4:&nbsp;&nbsp;&nbsp;&nbsp;e1a0c00d&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;ip,&nbsp;sp 800021a8:&nbsp;&nbsp;&nbsp;&nbsp;e92dd800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;push&nbsp;&nbsp;&nbsp;&nbsp;{fp,&nbsp;ip,&nbsp;lr,&nbsp;pc} 800021ac:&nbsp;&nbsp;&nbsp;&nbsp;e24cb004&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;fp,&nbsp;ip,&nbsp;#4 800021b0:&nbsp;&nbsp;&nbsp;&nbsp;e24dd010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;sp,&nbsp;#16 800021b4:&nbsp;&nbsp;&nbsp;&nbsp;e50b0018&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;[fp,&nbsp;#-24]&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xffffffe8 &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;b; &nbsp;&nbsp;&nbsp;&nbsp;b&nbsp;=&nbsp;0xff22; 800021b8:&nbsp;&nbsp;&nbsp;&nbsp;e30f3f22&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#65314&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xff22 800021bc:&nbsp;&nbsp;&nbsp;&nbsp;e50b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] &nbsp;&nbsp;&nbsp;&nbsp;test_c(0xcc00); 800021c0:&nbsp;&nbsp;&nbsp;&nbsp;e3a00b33&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;#52224&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xcc00 800021c4:&nbsp;&nbsp;&nbsp;&nbsp;eb000003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;bl&nbsp;&nbsp;&nbsp;&nbsp;800021d8&nbsp;&lt;test_c&gt; &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;b; 800021c8:&nbsp;&nbsp;&nbsp;&nbsp;e51b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldr&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] } 800021cc:&nbsp;&nbsp;&nbsp;&nbsp;e1a00003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;r3 800021d0:&nbsp;&nbsp;&nbsp;&nbsp;e24bd00c&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;fp,&nbsp;#12 800021d4:&nbsp;&nbsp;&nbsp;&nbsp;e89da800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldm&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;{fp,&nbsp;sp,&nbsp;pc} 800021d8&nbsp;&lt;test_c&gt;: int&nbsp;test_c(int&nbsp;arg0) { 800021d8:&nbsp;&nbsp;&nbsp;&nbsp;e1a0c00d&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;ip,&nbsp;sp 800021dc:&nbsp;&nbsp;&nbsp;&nbsp;e92dd800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;push&nbsp;&nbsp;&nbsp;&nbsp;{fp,&nbsp;ip,&nbsp;lr,&nbsp;pc} 800021e0:&nbsp;&nbsp;&nbsp;&nbsp;e24cb004&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;fp,&nbsp;ip,&nbsp;#4 800021e4:&nbsp;&nbsp;&nbsp;&nbsp;e24dd010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;sp,&nbsp;#16 800021e8:&nbsp;&nbsp;&nbsp;&nbsp;e50b0018&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;[fp,&nbsp;#-24]&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xffffffe8 &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;c; &nbsp;&nbsp;&nbsp;&nbsp;c&nbsp;=&nbsp;0xff33; 800021ec:&nbsp;&nbsp;&nbsp;&nbsp;e30f3f33&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#65331&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xff33 800021f0:&nbsp;&nbsp;&nbsp;&nbsp;e50b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;c; 800021f4:&nbsp;&nbsp;&nbsp;&nbsp;e51b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldr&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] } 800021f8:&nbsp;&nbsp;&nbsp;&nbsp;e1a00003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;r3 800021fc:&nbsp;&nbsp;&nbsp;&nbsp;e24bd00c&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;fp,&nbsp;#12 80002200:&nbsp;&nbsp;&nbsp;&nbsp;e89da800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldm&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;{fp,&nbsp;sp,&nbsp;pc} 80002204&nbsp;&lt;main&gt;: int&nbsp;main(void) { 80002204:&nbsp;&nbsp;&nbsp;&nbsp;e1a0c00d&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;ip,&nbsp;sp 80002208:&nbsp;&nbsp;&nbsp;&nbsp;e92dd800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;push&nbsp;&nbsp;&nbsp;&nbsp;{fp,&nbsp;ip,&nbsp;lr,&nbsp;pc} 8000220c:&nbsp;&nbsp;&nbsp;&nbsp;e24cb004&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;fp,&nbsp;ip,&nbsp;#4 80002210:&nbsp;&nbsp;&nbsp;&nbsp;e24dd010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;sp,&nbsp;#16 &nbsp;&nbsp;&nbsp;&nbsp;int&nbsp;val; &nbsp;&nbsp;&nbsp;&nbsp;val&nbsp;=&nbsp;0xff00; 80002214:&nbsp;&nbsp;&nbsp;&nbsp;e3a03cff&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#65280&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xff00 80002218:&nbsp;&nbsp;&nbsp;&nbsp;e50b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16] &nbsp;&nbsp;&nbsp;&nbsp;test_a(0xaa00,&nbsp;0xaa11,&nbsp;0xaa22,&nbsp;0xaa33,&nbsp;0xaa44); 8000221c:&nbsp;&nbsp;&nbsp;&nbsp;e30a3a44&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#43588&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xaa44 80002220:&nbsp;&nbsp;&nbsp;&nbsp;e58d3000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;str&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[sp] 80002224:&nbsp;&nbsp;&nbsp;&nbsp;e30a3a33&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#43571&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xaa33 80002228:&nbsp;&nbsp;&nbsp;&nbsp;e30a2a22&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r2,&nbsp;#43554&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xaa22 8000222c:&nbsp;&nbsp;&nbsp;&nbsp;e30a1a11&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;movw&nbsp;&nbsp;&nbsp;&nbsp;r1,&nbsp;#43537&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xaa11 80002230:&nbsp;&nbsp;&nbsp;&nbsp;e3a00caa&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;#43520&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xaa00 80002234:&nbsp;&nbsp;&nbsp;&nbsp;ebffffca&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;bl&nbsp;&nbsp;&nbsp;&nbsp;80002164&nbsp;&lt;test_a&gt; &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;0; 80002238:&nbsp;&nbsp;&nbsp;&nbsp;e3a03000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;#0 } 8000223c:&nbsp;&nbsp;&nbsp;&nbsp;e1a00003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;r3 80002240:&nbsp;&nbsp;&nbsp;&nbsp;e24bd00c&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sub&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;fp,&nbsp;#12 80002244:&nbsp;&nbsp;&nbsp;&nbsp;e89da800&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldm&nbsp;&nbsp;&nbsp;&nbsp;sp,&nbsp;{fp,&nbsp;sp,&nbsp;pc}</pre><p>当程序运行到<code>test_c()</code>函数的<code>return c;</code>代码处时,FP的值为0x9FDFFF94,此时内存数据如下:</p><p style="text-align:center"><img src="/uploads/AilsonJack/2023.10.14/112414248826393.png" onclick="preview_image(&#39;/uploads/AilsonJack/2023.10.14/112414248826393.png&#39;)"/></p><p><code>test_c()</code>函数的栈底为0x9FDFFF94,可以得到<code>test_c()</code>函数栈帧中LR为0x800021C8、FP为0x9FDFFFB4,LR是<code>test_c()</code>函数执行完成后的返回地址,与反汇编代码中<code>test_b()</code>函数调用完<code>test_c()</code>之后的下一个执行地址一致:</p><pre class="md-fences md-end-block ty-contain-cm modeLoaded" spellcheck="false" lang="c">800021c0:&nbsp;&nbsp;&nbsp;&nbsp;e3a00b33&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mov&nbsp;&nbsp;&nbsp;&nbsp;r0,&nbsp;#52224&nbsp;&nbsp;&nbsp;&nbsp;;&nbsp;0xcc00 800021c4:&nbsp;&nbsp;&nbsp;&nbsp;eb000003&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;bl&nbsp;&nbsp;&nbsp;&nbsp;800021d8&nbsp;&lt;test_c&gt; &nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;b; 800021c8:&nbsp;&nbsp;&nbsp;&nbsp;e51b3010&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ldr&nbsp;&nbsp;&nbsp;&nbsp;r3,&nbsp;[fp,&nbsp;#-16]&nbsp;//&nbsp;test_c()&nbsp;函数返回后继续执行的地址</pre><p>FP为0x9FDFFFB4表示<code>test_b()</code>函数的栈底为0x9FDFFFB4,有了<code>test_b()</code>函数的栈底就可以得到<code>test_b()</code>函数栈帧中LR为0x80002194、FP为0x9FDFFFDC,从而知道<code>test_b()</code>函数执行完成后的返回地址以及<code>test_a()</code>函数的栈底,依次逐级回溯,就可以知道程序的整个运行流程了。</p><p>在栈回溯的过程中我们可以利用addr2line工具辅助我们对程序执行流程的分析。</p><!--!doctype-->
欢迎关注博主的公众号呀,精彩内容随时掌握:
热情邀请仔细浏览下博客中的广告,万一有对自己有用或感兴趣的呢。◕ᴗ◕。。
如果这篇文章对你有帮助,记得点赞和关注博主就行了^_^,当然了能够赞赏博主,那就非常感谢啦!
注: 转载请注明出处,谢谢!^_^
转载请注明来源: 本文链接:  By: AilsonJack
ARMv7-A 那些事 - 7.栈回溯浅析  |  说好一起走
暂无评论,要不要来个沙发
发表评论

 
Copyright © 2015~2023  说好一起走   保留所有权利   |  百度统计  蜀ICP备15004292号