📄 system_call.s
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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/kernel/system_call.s</title><meta http-equiv=Content-Type content="text/html; charset=gb2312"><base href="http://oldlinux.org/lxr/http/"></head><body bgcolor=white><div align=center> [<b><i>源代码浏览</i></b>] [<a href="diff/kernel/system_call.s">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>]</div><h1 align=center> <a href="http:/"> OldLinux</a> <a href="http:blurb.html"> 交叉引用</a><br> <a href="source/">Linux</a>/<a href="source/kernel/">kernel</a>/<a href="source/kernel/system_call.s">system_call.s</a></h1><div align=center> <b>版本:</b> [<a href="source/kernel/system_call.s?v=1.0">1.0</a>] [<a href="source/kernel/system_call.s?v=0.99.11">0.99.11</a>] [<a href="source/kernel/system_call.s?v=0.99">0.99</a>] [<a href="source/kernel/system_call.s?v=0.97">0.97</a>] [<a href="source/kernel/system_call.s?v=0.96a">0.96a</a>] [<a href="source/kernel/system_call.s?v=0.95">0.95</a>] [<a href="source/kernel/system_call.s?v=0.12">0.12</a>] [<b><i>0.11</i></b>] [<a href="source/kernel/system_call.s?v=0.01">0.01</a>] <br> <b>体系结构:</b> [<b><i>i386</i></b>] <br></div><hr><pre> <a name=L1 href="source/kernel/system_call.s#L1">1</a> /* <a name=L2 href="source/kernel/system_call.s#L2">2</a> * linux/kernel/system_call.s <a name=L3 href="source/kernel/system_call.s#L3">3</a> * <a name=L4 href="source/kernel/system_call.s#L4">4</a> * (C) 1991 Linus Torvalds <a name=L5 href="source/kernel/system_call.s#L5">5</a> */ <a name=L6 href="source/kernel/system_call.s#L6">6</a> <a name=L7 href="source/kernel/system_call.s#L7">7</a> /* <a name=L8 href="source/kernel/system_call.s#L8">8</a> * system_call.s contains the system-call low-level handling routines. <a name=L9 href="source/kernel/system_call.s#L9">9</a> * This also contains the timer-interrupt handler, as some of the code is <a name=L10 href="source/kernel/system_call.s#L10">10</a> * the same. The hd- and flopppy-interrupts are also here. <a name=L11 href="source/kernel/system_call.s#L11">11</a> * <a name=L12 href="source/kernel/system_call.s#L12">12</a> * NOTE: This code handles signal-recognition, which happens every time <a name=L13 href="source/kernel/system_call.s#L13">13</a> * after a timer-interrupt and after each system call. Ordinary interrupts <a name=L14 href="source/kernel/system_call.s#L14">14</a> * don't handle signal-recognition, as that would clutter them up totally <a name=L15 href="source/kernel/system_call.s#L15">15</a> * unnecessarily. <a name=L16 href="source/kernel/system_call.s#L16">16</a> * <a name=L17 href="source/kernel/system_call.s#L17">17</a> * Stack layout in 'ret_from_system_call': <a name=L18 href="source/kernel/system_call.s#L18">18</a> * <a name=L19 href="source/kernel/system_call.s#L19">19</a> * 0(%esp) - %eax <a name=L20 href="source/kernel/system_call.s#L20">20</a> * 4(%esp) - %ebx <a name=L21 href="source/kernel/system_call.s#L21">21</a> * 8(%esp) - %ecx <a name=L22 href="source/kernel/system_call.s#L22">22</a> * C(%esp) - %edx <a name=L23 href="source/kernel/system_call.s#L23">23</a> * 10(%esp) - %fs <a name=L24 href="source/kernel/system_call.s#L24">24</a> * 14(%esp) - %es <a name=L25 href="source/kernel/system_call.s#L25">25</a> * 18(%esp) - %ds <a name=L26 href="source/kernel/system_call.s#L26">26</a> * 1C(%esp) - %eip <a name=L27 href="source/kernel/system_call.s#L27">27</a> * 20(%esp) - %cs <a name=L28 href="source/kernel/system_call.s#L28">28</a> * 24(%esp) - %eflags <a name=L29 href="source/kernel/system_call.s#L29">29</a> * 28(%esp) - %oldesp <a name=L30 href="source/kernel/system_call.s#L30">30</a> * 2C(%esp) - %oldss <a name=L31 href="source/kernel/system_call.s#L31">31</a> */ <a name=L32 href="source/kernel/system_call.s#L32">32</a> <a name=L33 href="source/kernel/system_call.s#L33">33</a> SIG_CHLD = 17 <a name=L34 href="source/kernel/system_call.s#L34">34</a> <a name=L35 href="source/kernel/system_call.s#L35">35</a> EAX = 0x00 <a name=L36 href="source/kernel/system_call.s#L36">36</a> EBX = 0x04 <a name=L37 href="source/kernel/system_call.s#L37">37</a> ECX = 0x08 <a name=L38 href="source/kernel/system_call.s#L38">38</a> EDX = 0x0C <a name=L39 href="source/kernel/system_call.s#L39">39</a> FS = 0x10 <a name=L40 href="source/kernel/system_call.s#L40">40</a> ES = 0x14 <a name=L41 href="source/kernel/system_call.s#L41">41</a> DS = 0x18 <a name=L42 href="source/kernel/system_call.s#L42">42</a> EIP = 0x1C <a name=L43 href="source/kernel/system_call.s#L43">43</a> CS = 0x20 <a name=L44 href="source/kernel/system_call.s#L44">44</a> EFLAGS = 0x24 <a name=L45 href="source/kernel/system_call.s#L45">45</a> OLDESP = 0x28 <a name=L46 href="source/kernel/system_call.s#L46">46</a> OLDSS = 0x2C <a name=L47 href="source/kernel/system_call.s#L47">47</a> <a name=L48 href="source/kernel/system_call.s#L48">48</a> state = 0 # these are offsets into the task-struct. <a name=L49 href="source/kernel/system_call.s#L49">49</a> counter = 4 <a name=L50 href="source/kernel/system_call.s#L50">50</a> priority = 8 <a name=L51 href="source/kernel/system_call.s#L51">51</a> signal = 12 <a name=L52 href="source/kernel/system_call.s#L52">52</a> sigaction = 16 # MUST be 16 (=len of sigaction) <a name=L53 href="source/kernel/system_call.s#L53">53</a> blocked = (33*16) <a name=L54 href="source/kernel/system_call.s#L54">54</a> <a name=L55 href="source/kernel/system_call.s#L55">55</a> # offsets within sigaction <a name=L56 href="source/kernel/system_call.s#L56">56</a> sa_handler = 0 <a name=L57 href="source/kernel/system_call.s#L57">57</a> sa_mask = 4 <a name=L58 href="source/kernel/system_call.s#L58">58</a> sa_flags = 8 <a name=L59 href="source/kernel/system_call.s#L59">59</a> sa_restorer = 12 <a name=L60 href="source/kernel/system_call.s#L60">60</a> <a name=L61 href="source/kernel/system_call.s#L61">61</a> nr_system_calls = 72 <a name=L62 href="source/kernel/system_call.s#L62">62</a> <a name=L63 href="source/kernel/system_call.s#L63">63</a> /* <a name=L64 href="source/kernel/system_call.s#L64">64</a> * Ok, I get parallel printer interrupts while using the floppy for some <a name=L65 href="source/kernel/system_call.s#L65">65</a> * strange reason. Urgel. Now I just ignore them. <a name=L66 href="source/kernel/system_call.s#L66">66</a> */ <a name=L67 href="source/kernel/system_call.s#L67">67</a> .globl _system_call,_sys_fork,_timer_interrupt,_sys_execve <a name=L68 href="source/kernel/system_call.s#L68">68</a> .globl _hd_interrupt,_floppy_interrupt,_parallel_interrupt <a name=L69 href="source/kernel/system_call.s#L69">69</a> .globl _device_not_available, _coprocessor_error <a name=L70 href="source/kernel/system_call.s#L70">70</a> <a name=L71 href="source/kernel/system_call.s#L71">71</a> .align 2 <a name=L72 href="source/kernel/system_call.s#L72">72</a> bad_sys_call: <a name=L73 href="source/kernel/system_call.s#L73">73</a> movl $-1,%eax <a name=L74 href="source/kernel/system_call.s#L74">74</a> iret <a name=L75 href="source/kernel/system_call.s#L75">75</a> .align 2 <a name=L76 href="source/kernel/system_call.s#L76">76</a> reschedule: <a name=L77 href="source/kernel/system_call.s#L77">77</a> pushl $ret_from_sys_call <a name=L78 href="source/kernel/system_call.s#L78">78</a> jmp _schedule <a name=L79 href="source/kernel/system_call.s#L79">79</a> .align 2 <a name=L80 href="source/kernel/system_call.s#L80">80</a> _system_call: <a name=L81 href="source/kernel/system_call.s#L81">81</a> cmpl $nr_system_calls-1,%eax <a name=L82 href="source/kernel/system_call.s#L82">82</a> ja bad_sys_call <a name=L83 href="source/kernel/system_call.s#L83">83</a> push %ds <a name=L84 href="source/kernel/system_call.s#L84">84</a> push %es <a name=L85 href="source/kernel/system_call.s#L85">85</a> push %fs <a name=L86 href="source/kernel/system_call.s#L86">86</a> pushl %edx <a name=L87 href="source/kernel/system_call.s#L87">87</a> pushl %ecx # push %ebx,%ecx,%edx as parameters <a name=L88 href="source/kernel/system_call.s#L88">88</a> pushl %ebx # to the system call <a name=L89 href="source/kernel/system_call.s#L89">89</a> movl $0x10,%edx # set up ds,es to kernel space <a name=L90 href="source/kernel/system_call.s#L90">90</a> mov %dx,%ds <a name=L91 href="source/kernel/system_call.s#L91">91</a> mov %dx,%es <a name=L92 href="source/kernel/system_call.s#L92">92</a> movl $0x17,%edx # fs points to local data space <a name=L93 href="source/kernel/system_call.s#L93">93</a> mov %dx,%fs <a name=L94 href="source/kernel/system_call.s#L94">94</a> call _sys_call_table(,%eax,4) <a name=L95 href="source/kernel/system_call.s#L95">95</a> pushl %eax <a name=L96 href="source/kernel/system_call.s#L96">96</a> movl _current,%eax <a name=L97 href="source/kernel/system_call.s#L97">97</a> cmpl $0,state(%eax) # state <a name=L98 href="source/kernel/system_call.s#L98">98</a> jne reschedule <a name=L99 href="source/kernel/system_call.s#L99">99</a> cmpl $0,counter(%eax) # counter<a name=L100 href="source/kernel/system_call.s#L100">100</a> je reschedule<a name=L101 href="source/kernel/system_call.s#L101">101</a> ret_from_sys_call:<a name=L102 href="source/kernel/system_call.s#L102">102</a> movl _current,%eax # task[0] cannot have signals<a name=L103 href="source/kernel/system_call.s#L103">103</a> cmpl _task,%eax<a name=L104 href="source/kernel/system_call.s#L104">104</a> je 3f<a name=L105 href="source/kernel/system_call.s#L105">105</a> cmpw $0x0f,CS(%esp) # was old code segment supervisor ?<a name=L106 href="source/kernel/system_call.s#L106">106</a> jne 3f<a name=L107 href="source/kernel/system_call.s#L107">107</a> cmpw $0x17,OLDSS(%esp) # was stack segment = 0x17 ?<a name=L108 href="source/kernel/system_call.s#L108">108</a> jne 3f<a name=L109 href="source/kernel/system_call.s#L109">109</a> movl signal(%eax),%ebx<a name=L110 href="source/kernel/system_call.s#L110">110</a> movl blocked(%eax),%ecx<a name=L111 href="source/kernel/system_call.s#L111">111</a> notl %ecx<a name=L112 href="source/kernel/system_call.s#L112">112</a> andl %ebx,%ecx<a name=L113 href="source/kernel/system_call.s#L113">113</a> bsfl %ecx,%ecx<a name=L114 href="source/kernel/system_call.s#L114">114</a> je 3f<a name=L115 href="source/kernel/system_call.s#L115">115</a> btrl %ecx,%ebx<a name=L116 href="source/kernel/system_call.s#L116">116</a> movl %ebx,signal(%eax)<a name=L117 href="source/kernel/system_call.s#L117">117</a> incl %ecx<a name=L118 href="source/kernel/system_call.s#L118">118</a> pushl %ecx<a name=L119 href="source/kernel/system_call.s#L119">119</a> call _do_signal<a name=L120 href="source/kernel/system_call.s#L120">120</a> popl %eax<a name=L121 href="source/kernel/system_call.s#L121">121</a> 3: popl %eax<a name=L122 href="source/kernel/system_call.s#L122">122</a> popl %ebx<a name=L123 href="source/kernel/system_call.s#L123">123</a> popl %ecx<a name=L124 href="source/kernel/system_call.s#L124">124</a> popl %edx<a name=L125 href="source/kernel/system_call.s#L125">125</a> pop %fs<a name=L126 href="source/kernel/system_call.s#L126">126</a> pop %es<a name=L127 href="source/kernel/system_call.s#L127">127</a> pop %ds<a name=L128 href="source/kernel/system_call.s#L128">128</a> iret<a name=L129 href="source/kernel/system_call.s#L129">129</a> <a name=L130 href="source/kernel/system_call.s#L130">130</a> .align 2<a name=L131 href="source/kernel/system_call.s#L131">131</a> _coprocessor_error:<a name=L132 href="source/kernel/system_call.s#L132">132</a> push %ds<a name=L133 href="source/kernel/system_call.s#L133">133</a> push %es⌨️ 快捷键说明
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