{ "version": "https://jsonfeed.org/version/1", "title": "\u6c47\u7f16", "description": "", "home_page_url": "go/assembly", "feed_url": "feed/assembly.json", "items": [ { "author": { "url": "member/foxyier", "name": "foxyier", "avatar": "https://cdn.v2ex.com/gravatar/1f81470bfe2e5790748810e44269bbc9?s=73&d=retro" }, "url": "t/1041265", "title": "\u5728\u6d4f\u89c8\u5668\u4f7f\u7528 wasm \u5982\u4f55\u89e3\u51b3\u517c\u5bb9\u6027\u95ee\u9898", "id": "t/1041265", "date_published": "2024-05-16T03:54:51+00:00", "content_html": "

\u4e3a\u4e86\u5b89\u5168\u8003\u8651\uff0c \u6253\u7b97\u91c7\u7528 wasm \u4fdd\u62a4\u52a0\u5bc6\u7b97\u6cd5\u3002

\n

\u4f46\u662f\u9488\u5bf9\u4e0d\u517c\u5bb9\u7684\u6d4f\u89c8\u5668\uff0c\u5982\u4f55\u80fd\u505a\u5230\u964d\u7ea7\u7684\u540c\u65f6\u4e0d\u4f1a\u51fa\u73b0\u6f0f\u6d1e\u5462\u3002

\n

\u60f3\u8bf7\u6559\u4e00\u4e0b\u5927\u4f6c\u4eec\u9488\u5bf9\u8fd9\u79cd\u573a\u666f\u90fd\u662f\u600e\u4e48\u505a\u7684\u3002

\n" }, { "author": { "url": "member/huzhikuizainali", "name": "huzhikuizainali", "avatar": "https://cdn.v2ex.com/avatar/1869/a390/522912_large.png?m=1752498684" }, "url": "t/1017817", "title": "C++\u4e2d i=i; \u4e0e *p=i; \u5bf9\u5e94\u7684\u6c47\u7f16\u4ee3\u7801\u4e3a\u4ec0\u4e48\u4e0d\u4e00\u6837\uff1f", "id": "t/1017817", "date_published": "2024-02-23T03:56:41+00:00", "content_html": "\u300a C++ Primer \u300b P48 \u95ee\u8fd9\u4e2a\u95ee\u9898\u7684\u76ee\u7684\u662f\u5e0c\u671b\u66f4\u6df1\u5165\u7406\u89e3 C++\u7684\u6307\u9488
int i=42;
int &r=i;
int *p=&i;
*p=i;
i=i;

\u4e0a\u8ff0 C++\u4ee3\u7801\u4e2d i=i; \u4e0e *p=i; \u5bf9\u5e94\u7684\u6c47\u7f16\u4ee3\u7801\u4e3a\u4ec0\u4e48\u4e0d\u4e00\u6837\uff1f
\u5728

\u9898\u76ee\u8981\u6c42\u5982\u4e0b

\u5728\u5c4f\u5e55\u7684\u7b2c\u4e00\u884c\u663e\u793a\u6570\u636e belles \u3002\nbelles\tdb \"Reading is a happy thing. For those who love reading, once they read it,\"\t\u3002\u8bf7\u6839\u636e\u9700\u8981\u7f16\u5199\u5b50\u7a0b\u5e8f\uff0c\u5b9e\u73b0\uff1a\u4f9d\u6b21\u53d6\u8d70\u5b57\u7b26\uff0c\u5e76\u8ba9\u5b57\u7b26\u4ece\u5176\u4f4d\u7f6e\u8dcc\u843d\u5230\u5c4f\u5e55\u5e95\u90e8\u5e76\u6d88\u5931\u3002

\u6211\u81ea\u5df1\u7684\u60f3\u6cd5\u662f\u5c06\u505a\u597d\u51e0\u4e2a\u5faa\u73af\u6765\u5199\uff0c\u6bd4\u5982\u7b2c\u4e00\u4e2a\u5faa\u73af\u8ba9\u7b2c\u4e00\u4e2a\u5b57\u7b26\u5f80\u4e0b\u6389\uff0c\u7b2c\u4e8c\u4e2a\u5c31\u8ba9\u7b2c\u4e8c\u4e2a\u5f80\u4e0b\u6389\u5565\u7684\uff0c\u4f46\u662f\u6211\u5199\u4e86\u4e00\u4e2a\u53d1\u73b0\u505a\u8fd9\u6837\u7684\u5faa\u73af\u76f4\u63a5\u8fd0\u884c\u4e4b\u540e DosBox \u4f1a\u76f4\u63a5\u5361\u6b7b\uff0c\u95ee GPT \uff0c\u4f46\u662f GPT \u81ea\u5df1\u7ed9\u7684\u4ee3\u7801\u603b\u662f\u6709\u95ee\u9898\uff0c\u767e\u5ea6\u4e00\u4e0b\u4e5f\u53ea\u80fd\u627e\u5230\u4e00\u4e2a\u4ee3\u7801\uff0c\u90a3\u4e2a\u4ee3\u7801\u4e5f\u4e0d\u80fd\u5b9e\u73b0\u9898\u76ee\u8981\u6c42\u7684\u6548\u679c\uff0c\u505a\u4e86\u51e0\u4e2a\u5c0f\u65f6\u4e86\u8fd8\u5361\u5728\u8fd9

\u6211\u771f\u7684\u6ca1\u529e\u6cd5\u4e86\uff0c\u6240\u4ee5\u6211\u6765\u8bf7\u6559\u5404\u4f4d\uff0c\u6c42\u6c42\u5404\u4f4d\u5927\u4f6c\u5e2e\u5e2e\u6211\u5427\n\u5982\u679c\u7ed9\u4e0d\u4e86\u4ee3\u7801\uff0c\u7ed9\u6211\u70b9\u601d\u8def\u4e5f\u884c\uff0c\u6211\u81ea\u5df1\u4f1a\u53bb\u8bd5\u7684

\u9898\u76ee\u8981\u6c42\u662f\u8fd9\u6837\u7684

\u5728\u5c4f\u5e55\u4e2d\u7684\u7b2c 10 \u884c\u5230 15 \u884c\u7684\u7b2c 20 \u5217\u5f00\u59cb\u663e\u793a\u5982\u4e0b\u83dc\u5355\uff1a\nArithmetic system of primary school

\n
1. add
\n
2. subtract
\n
3. multiply
\n
4. divide
\n

\u7136\u540e\u6211\u5199\u51fa\u4e86\u4e0b\u9762\u7684\u4ee3\u7801

assume cs:codesg, ds:datasg\ndatasg segment\n welcome db 'Arithmetic system of primary school$'\n file db '1. add$'\n insert db '2. subtract$'\n modify db '3. multiply$'\n exit db '4. devide$'\ndatasg ends\n \ncodesg segment\nstart:\n\n mov ax, datasg\n mov ds, ax\n \n mov ah, 02h \n mov dh, 09h \n mov dl, 13h \n int 10h \n \n lea dx, welcome\n mov ah, 09h\n int 21h \n \n mov ah, 02h \n mov dh, 10h \n mov dl, 13h \n int 10h \n \n lea dx, file\n mov ah, 09h\n int 21h \n \n mov ah, 02h \n mov dh, 11h \n mov dl, 13h \n int 10h \n \n lea dx, insert\n mov ah, 09h\n int 21h\n \n mov ah, 02h \n mov dh, 12h \n mov dl, 13h \n int 10h \n \n lea dx, modify\n mov ah, 09h\n int 21h\n \n mov ah, 02h \n mov dh, 13h \n mov dl, 13h \n int 10h \n \n lea dx, exit\n mov ah, 09h\n int 21h\n \n ;\u7b49\u5f85\u7528\u6237\u6309\u952e\n mov ah, 07h \n int 21h \n \n mov ah, 4ch \n int 21h \ncodesg ends\nend start\n

\u8fd9\u4e2a\u4ee3\u7801\u53ef\u4ee5\u6b63\u786e\u663e\u793a\u51fa\u6211\u8981\u7684\u5185\u5bb9\uff0c\u4f46\u662f\u7b2c\u4e00\u884c\u548c\u7b2c\u4e8c\u884c\u4e4b\u95f4\u603b\u662f\u6709\u7a7a\u884c\uff0c\u5177\u4f53\u8868\u73b0\u5982\u4e0b

\u6211\u771f\u7684\u60f3\u4e0d\u660e\u767d\u95ee\u9898\u51fa\u5728\u54ea\u91cc\n\u4e0d\u8bba\u662f\u95ee\u767e\u5ea6\u8fd8\u662f\u95ee gpt \u90fd\u4e0d\u592a\u7ba1\u7528\uff0c\u6211\u6ca1\u6cd5\u4e86\u6240\u4ee5\u6765\u95ee\u95ee\u5404\u4f4d\uff0c\u5e0c\u671b\u6709\u61c2\u7684\u6551\u4e00\u4e0b\uff0c\u6211\u5148\u8c22\u8c22\u5404\u4f4d\u4e86

\u5df2\u7ecf\u770b\u8fc7\u4e86\u738b\u723d\u8001\u5e08\u7684\u300a\u6c47\u7f16\u8bed\u8a00\u300b\uff0c\u8bb2\u7684\u5f88\u597d\uff0c\u4f46\u662f\u662f\u7528 8086 \u5165\u95e8\u7684\u3002\u60f3\u8fdb\u4e00\u6b65\u5b66\u4e60\uff0c\u6709\u6ca1\u6709\u63a8\u8350\u7684\u6559\u6750\uff0c\u73b0\u5728\u5728\u770b\u300a\u4ece\u5b9e\u6a21\u5f0f\u5230\u4fdd\u62a4\u6a21\u5f0f\u300b\uff0c\u8fd9\u672c\u600e\u4e48\u6837\uff1f

\u4ee5\u4e0b\u662f\u6e90\u7801\uff1a

int duplicate(int n)\n{\n return n * 2;\n}\nint global_var = duplicate(0x42);\n\nint main(int argc, char** argv){\n return global_var;\n}\n

\u6709\u4e00\u4e2a global variable, \u7528\u4ee5\u4e0b\u547d\u4ee4\u7f16\u8bd1\uff0c\u5e76\u67e5\u770b\u6c47\u7f16\u4ee3\u7801\uff1a

g++ -o main ./main.c -O0\nobjdump -C -S -s main\n

\u5176\u8f93\u51fa\u53ef\u89c1\uff1a https://controlc.com/70c59b1e

\u603b\u662f\u542c\u522b\u4eba\u8bf4\uff0cstatic storage variable(\u57fa\u672c\u4e0a\u5c31\u662f global variable)\u5728\u8fdb\u5165main\u4e4b\u524d\u5c31\u88ab\u521d\u59cb\u5316\u4e86\uff0c\u4f46\u662f\u5728\u67e5\u770b\u6c47\u7f16\u4ee3\u7801\u65f6\uff0c\u6211\u5e76\u6ca1\u6709\u627e\u5230\u76f8\u5173\u7684\u8c03\u7528\u3002

__static_initialization_and_destruction_0(int, int)\u770b\u8d77\u6765\u50cf\u662f\u521d\u59cb\u5316global_var\uff0c\u88ab_GLOBAL__sub_I__Z9duplicatei\u8c03\u7528\uff0c\u4f46\u662f\u6211\u6ca1\u6709\u5728\u4efb\u4f55\u5730\u65b9\u770b\u5230\u5bf9_GLOBAL__sub_I__Z9duplicatei\u7684\u8c03\u7528\u3002\u56e0\u6b64\u60f3\u8bf7\u95ee\u6211\u7684\u601d\u8def\u5bf9\u4e48\uff1f

\u6700\u8fd1\u5728\u770b\u539f\u5b50\u64cd\u4f5c\u7684\u539f\u7406\uff0c\u5f97\u77e5\u662f\u901a\u8fc7 Lock \u6307\u4ee4\u4fdd\u8bc1\u4e86\u5185\u5b58\u8bfb\u5199\u539f\u5b50\u6027\uff0c\u5176\u539f\u7406\u662f

\n
• CPU \u4fdd\u8bc1 Lock \u540e\u7f00\u540e\u8ddf\u7684\u6307\u4ee4\u539f\u5b50\u6027
\n
• \u8001 CPU \u4e0a\u901a\u8fc7\u9501\u603b\u7ebf\u6765\u4fdd\u8bc1\u53ef\u89c1\u6027
\n
• \u65b0 CPU \u4e0a\u5982\u679c\u6570\u636e\u5b58\u5728\u4e8e cpu cache \u4e0a\u65f6\u901a\u8fc7 MESI \u534f\u8bae\u6765\u5b9e\u73b0\u53ef\u89c1\u6027\uff0c\u5426\u5219\u8fd8\u662f\u9501\u603b\u7ebf
\n

\u5bf9\u6b64\u6211\u4ea7\u751f\u4e86\u51e0\u4e2a\u95ee\u9898\uff1a

\n
1. \u96be\u9053\u4e0d\u58f0\u660e Lock CPU \u5c31\u4e0d\u901a\u8fc7 MESI \u534f\u8bae\u4fdd\u8bc1 cache \u4e00\u81f4\u6027\u5417\uff1f\u6211\u89c9\u5f97\u4e0d\u662f, https://strikefreedom.top/cpu-caches-theory-and-application \u8fd9\u7bc7\u6587\u7ae0\u7684 demo \u4e2d\u5e76\u6ca1\u6709\u58f0\u660e Lock \u6307\u4ee4\uff0c\u4f46\u4ecd\u7136\u51fa\u73b0\u4e86\u7f13\u5b58\u5931\u6548\u3002
\n
2. \u662f\u4e0d\u662f\u9664\u4e86 cpu cache \u5916\u8fd8\u6709 store buffer \u548c invalid queue \u4f1a\u5f71\u54cd\u53ef\u89c1\u6027\uff0c\u6240\u4ee5 CPU \u53ea\u80fd\u4fdd\u8bc1 cache \u7684\u4e00\u81f4\u6027\u4f46\u4fdd\u8bc1\u4e0d\u4e86\u5176\u4ed6\u786c\u4ef6\u7f13\u5b58\u5c42\u9762\u7684\u4e00\u81f4\u6027\uff0c\u6240\u4ee5\u8fd8\u662f\u9700\u8981 Lock \u6307\u4ee4\uff1f
\n

\u4e00\u3001\u5229\u7528 DOS \u7cfb\u7edf\u529f\u80fd\u8c03\u7528\u7f16\u5199\u6c47\u7f16\u7a0b\u5e8f\uff0c\u5728\u5c4f\u5e55\u4e0a\u663e\u793a\u81ea\u5df1\u59d3\u7684\u62fc\u97f3\u548c\u5b66\u53f7\u7684\u540e 4 \u4e2a\u6570\u5b57\u7b26\u53f7\u3002\u4f8b\u5982\uff0c\u4f60\u59d3\u201c\u674e\u201d\uff0c\u4f60\u7684\u5b66\u53f7\u662f\u201c20201234\u201d\uff0c\u5219\u5728\u5c4f\u5e55\u4e0a\u663e\u793a\u51fa\u201cLI\uff1a1234\u201d\u3002\u5177\u4f53\u8981\u6c42\u5982\u4e0b\uff1a\n\uff08 1 \uff09\u7f16\u5199\u51fa\u5b8c\u6574\u7684\u6c47\u7f16\u8bed\u8a00\u7a0b\u5e8f\uff1b\n\uff08 2 \uff09\u5229\u7528\u5b8f\u6c47\u7f16\u7a0b\u5e8f MASM \u548c\u8fde\u63a5\u7a0b\u5e8f LINK \u5bf9\u6240\u7f16\u5199\u7684\u7a0b\u5e8f\u8fdb\u884c\u6c47\u7f16\u548c\u8fde\u63a5\uff0c\u751f\u6210\u53ef\u6267\u884c\u6587\u4ef6\uff0c\u5e76\u5728 DOS \u4e0b\u8fd0\u884c\u7a0b\u5e8f\u3002\n\uff08 3 \uff09\u6253\u5370\u51fa\u76f8\u5e94\u7684\u5217\u8868\u6587\u4ef6\uff08\u540e\u7f00 lst \u7684\u6587\u4ef6\uff09\u6e05\u5355\uff0c\u5e76\u5bf9\u8c03\u8bd5\u8fd0\u884c\u7ed3\u679c\u8fdb\u884c\u622a\u56fe\uff0c\u4ee5\u8bc1\u660e\u7a0b\u5e8f\u8c03\u8bd5\u6210\u529f\u3002

\u4e8c\u3001\u57fa\u4e8e 8088CPU \u8bbe\u8ba1\u4e00\u4e2a\u6a21\u62df\u6570\u636e\u91c7\u96c6\u7cfb\u7edf\u3002\n\u5177\u4f53\u8981\u6c42\u5982\u4e0b\uff1a\n\uff08 1 \uff09\u91c7\u7528 ADC0809 A/D \u8f6c\u6362\u5668\u4e0e Intel 8255 \u53ef\u7f16\u7a0b\u5e76\u884c\u63a5\u53e3\u82af\u7247\u8bbe\u8ba1\u63a5\u53e3\u7535\u8def\u3002\u8bbe 8255 \u7684 PA \u4e3a\u6570\u636e\u53e3\uff0cPB \u3001PC \u4e3a\u63a7\u5236\u53e3\uff0c\u8f93\u5165\u6a21\u62df\u91cf\u63a5\u5165 ADC0809 \u7684 IN1 \u901a\u9053\u3002\u753b\u51fa ADC 0809 \u901a\u8fc7 Intel 8255 \u4e0e 8088CPU \u63a5\u53e3\u7684\u7535\u8def\u539f\u7406\u56fe\u3002\n\uff08 2 \uff09\u5047\u8bbe\u5730\u5740\u7801\u4e3a 3F0H~3F3H \u65f6 8255 \u7247\u9009\u4fe1\u53f7\u6709\u6548\uff0c\u91c7\u7528 74LS138 \u8bd1\u7801\u5668\u8bbe\u8ba1\u5730\u5740\u8bd1\u7801\u7535\u8def\u3002\u753b\u51fa\u5730\u5740\u8bd1\u7801\u5668\u4e0e CPU \u7cfb\u7edf\u548c 8255 \u4e4b\u95f4\u7684\u8fde\u7ebf\u56fe\u3002\n\uff08 3 \uff09\u7528\u6c47\u7f16\u8bed\u8a00\u7f16\u5199\u4e00\u6bb5\u7a0b\u5e8f\uff0c\u5b9e\u73b0\u4ece IN1 \u901a\u9053\u8bfb\u53d6 100 \u4e2a\u6570\u636e\u5e76\u5b58\u5165\u5185\u5b58\u6570\u636e\u6bb5\u4e2d\u3002

https://pdos.csail.mit.edu/6.828/2018/labs/lab1/

\u7248\u672c\uff1a

\n
• qemu\uff1aQEMU emulator version 1.5.3 (qemu-kvm-1.5.3-167.el7_7.4), Copyright (c) 2003-2008 Fabrice Bellard
\n
• centos\uff1aCentOS-7-x86_64-Minimal-1908
\n
• gdb\uff1aGNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-115.el7
\n

The ROM BIOS \u8fd9\u4e2a\u7ae0\u8282\uff0cA \u7a97\u53e3 make qemu-gdb\uff0cB \u7a97\u53e3 make gdb

A\uff1a

/usr/libexec/qemu-kvm -drive file=obj/kern/kernel.img,index=0,media=disk,format=raw -serial mon:stdio -gdb tcp::25000 -D qemu.log -S\nVNC server running on `::1:5900'\n

B si \u5355\u6b65\u8c03\u8bd5:

[f000:fff0] 0xffff0: ljmp $0xf000,$0xe05b\n[f000:e05b] 0xfe05b: cmpl $0x0,%cs:0x69c8\n[f000:e062] 0xfe062: jne 0xfd0f7\n[f000:e066] 0xfe066: xor %dx,%dx\n[f000:e068] 0xfe068: mov %dx,%ss\n[f000:e070] 0xfe070: mov $0xf1399,%edx\n[f000:e076] 0xfe076: jmp 0xfcf8c\n[f000:cf8c] 0xfcf8c: cli\n[f000:cf8d] 0xfcf8d: cld\n[f000:cf8e] 0xfcf8e: mov %eax,%ecx\n[f000:cf91] 0xfcf91: mov $0x8f,%eax\n[f000:cf97] 0xfcf97: out %al,$0x70\n[f000:cf9b] 0xfcf9b: in $0x92,%al\n[f000:cf9d] 0xfcf9d: or $0x2,%al\n[f000:cf9f] 0xfcf9f: out %al,$0x92\n[f000:cfa4] 0xfcfa4: lidtw %cs:0x69b8\n[f000:cfaa] 0xfcfaa: lgdtw %cs:0x6974\n[f000:cfb0] 0xfcfb0: mov %cr0,%ecx\n[f000:cfb3] 0xfcfb3: and $0x1fffffff,%ecx\n[f000:cfba] 0xfcfba: or $0x1,%ecx\n[f000:cfbe] 0xfcfbe: mov %ecx,%cr0\n

\u5207\u5165 PE \u4e4b\u540e\uff1a

The target architecture is assumed to be i386\n=> 0xfcfc9: mov $0x10,%ecx\n=> 0xfcfce: mov %ecx,%ds\n=> 0xfcfd0: mov %ecx,%es\n=> 0xfcfd2: mov %ecx,%ss\n=> 0xfcfd6: mov %ecx,%gs\n=> 0xfcfd8: jmp *%edx\n=> 0xf1399: sub $0x8,%esp\n=> 0xf139c: movl $0xf4254,0x4(%esp)\n=> 0xf13a4: movl $0xf390a,(%esp)\n=> 0xf13ab: call 0xee4dd\n=> 0xee4dd: lea 0x8(%esp),%ecx\n=> 0xee4e1: mov 0x4(%esp),%edx\n=> 0xee4e5: mov $0xf4200,%eax\n=> 0xee4ea: call 0xedd5a\n=> 0xedd5a: push %ebp\n=> 0xedd5b: push %edi\n=> 0xedd5c: push %esi\n=> 0xedd5d: push %ebx\n=> 0xedd5e: sub $0xc,%esp\n=> 0xedd61: mov %eax,%ebx\n=> 0xedd63: mov %edx,0x4(%esp)\n=> 0xedd67: mov %ecx,%ebp\n=> 0xedd69: mov 0x4(%esp),%esi\n=> 0xedd6d: movsbl (%esi),%edx\n=> 0xedd70: test %dl,%dl\n=> 0xedd72: je 0xedfb6\n=> 0xedd78: cmp $0x25,%dl\n=> 0xedd7b: jne 0xede1b\n=> 0xede1b: mov %ebx,%eax\n=> 0xede1d: call 0xec570\n=> 0xec570: mov %eax,%ecx\n=> 0xec572: movsbl %dl,%edx\n=> 0xec575: call *(%ecx)\n=> 0xec565: mov %edx,%eax\n=> 0xec567: mov 0xf683c,%dx\n=> 0xec56e: out %al,(%dx)\n=> 0xec577: ret\n\n=> 0xede22: jmp 0xedfaa\n=> 0xedfaa: lea 0x1(%esi),%eax\n=> 0xedfad: mov %eax,0x4(%esp)\n=> 0xedfb1: jmp 0xedd69\n=> 0xedd69: mov 0x4(%esp),%esi\n=> 0xedd6d: movsbl (%esi),%edx\n=> 0xedd70: test %dl,%dl\n=> 0xedd72: je 0xedfb6\n=> 0xedd78: cmp $0x25,%dl\n=> 0xedd7b: jne 0xede1b\n=> 0xede1b: mov %ebx,%eax\n=> 0xede1d: call 0xec570\n=> 0xec570: mov %eax,%ecx\n=> 0xec572: movsbl %dl,%edx\n=> 0xec575: call *(%ecx)\n=> 0xec565: mov %edx,%eax\n=> 0xec567: mov 0xf683c,%dx\n=> 0xec56e: out %al,(%dx)\n=> 0xec577: ret\n...\n

\u4e2d\u95f4\u9694\u5f00\u7684\u90a3\u4e00\u6bb5\u4e00\u76f4\u5230 ... \u5c31\u662f\u6b7b\u5faa\u73af\uff0c\u4f46\u662f\u5982\u679c\u8fd9\u4e2a\u65f6\u5019 c continue \u7684\u8bdd A \u53c8\u53ef\u4ee5\u8fdb kernel\uff0c\u800c\u4e14\u8bd5\u4e86\u65ad\u70b9\uff0c\u5e76\u6ca1\u6709\u8fdb 0x7c00\u3002

\u627e\u5230\u4e00\u7bc7\uff1ahttps://stackoverflow.com/questions/11408041/how-to-debug-the-linux-kernel-with-gdb-and-qemu/33203642#33203642\uff0c\u628a A \u7a97\u53e3\u6362\u6210\u76f4\u63a5\u6267\u884c\uff1a

/usr/libexec/qemu-kvm -drive file=obj/kern/kernel.img,index=0,media=disk,format=raw -serial mon:stdio -D qemu.log -S -s\n

\u5176\u5b9e\u5c31\u662f\u6362\u4e86 gdb TCP 1234 \u7aef\u53e3\uff0c\u7136\u540e\u6309\u7167 stackoverflow \u4e0a\u5728 B \u8fde 1234\uff1a

target remote localhost:1234\n

\u6700\u7ec8 si \u8fd8\u662f\u8fdb\u4e86\u6b7b\u5faa\u73af... \u53e6\u5916\u8bd5\u4e86 -bios \u53c2\u6570\uff0c\u4e5f\u786e\u5b9e\u662f\u4f7f\u7528\u7684 seabios.bin\u3002

\u5df2\u7ecf\u67e5\u4e0d\u52a8\u4e86\uff0c\u6c42\u5927\u4f6c\u89e3\u7b54~

\u5404\u4f4d\u5927\u4f6c\u597d\uff0c\u60f3\u95ee\u4e00\u4e2a\u5173\u4e8e\u6c47\u7f16\u548c ShellCode \u4e2d\u96f6\u5b57\u8282\u7684\u95ee\u9898\u3002

\u5728\u5b66\u4e60\u7f13\u51b2\u6ea2\u51fa\u65f6\uff0c\u6211\u6839\u636e\u8981\u6c42\u5199\u4e86\u4e00\u6bb5\u53d6\u5f97\u7a0b\u5e8f PID \u7684\u6c47\u7f16\u6765\u6784\u9020 ShellCode\uff0c\u5176\u4e2d\u4e00\u6bb5\u8c03\u7528\u4e86 C \u4e2d\u7684 printf \u6765\u8f93\u51fa\u7ed3\u679c\uff1a

lea rdi, [rel message]\nmov rsi, rax\ncall printf\n

\u53cd\u6c47\u7f16\u540e\u7684\u7ed3\u679c\u5982\u4e0b\uff1a

 13:\t48 8d 3d e8 ff ff ff \tlea -0x18(%rip),%rdi # 2 <message>\n 1a:\t48 89 c6 \tmov %rax,%rsi\n 1d:\te8 00 00 00 00 \tcallq 22 <code+0x19>\n

\u5982\u4e0a\u9762\u4ee3\u7801\u7b2c\u4e09\u884c\u6240\u793a\uff0copcode \u51fa\u73b0\u4e86 \\x00\uff0c \u6211\u641c\u7d22\u4e86\u4e00\u5708\u90fd\u6ca1\u6709\u5408\u9002\u7684\u80fd\u628a \\x00 \u66ff\u6362\u6389\u7684\u65b9\u6848\uff0c\u4e8e\u662f\u60f3\u6765 V \u7ad9\u95ee\u95ee\u5404\u4f4d\u5927\u4f6c\u4eec\uff5e