如何编译内核？ [英] How to compile kernel?

问题描述

我创建了一个简单的c内核，它使用nasm打印Hello world和另一个目标文件。我的问题是如何使用gcc编译c内核，然后通过链接两个目标文件并放置地址0x7e12来创建平面二进制内核。它应该是32位内核。我在Lubuntu 14.04



我尝试过：



i有看到一些样品并厌倦了这个，但这没有给出正确的答案。



Compile.sh：

I have created a simple c kernel that prints Hello world and an another object file using nasm. my question is how to compile c kernel with gcc and after that create flat binary kernel by linking both object files and put on address 0x7e12. It should be 32bit kernel. I am on Lubuntu 14.04

What I have tried:

i have seen some samples and tired this but this does not give correct thing.

Compile.sh:

gcc -c kernel.c -o kernel.o
<br />nasm base.asm -f elf -o base.o
<br />ld -oformat=binary kernel.o base.o -Ttext=0x7e12

base.asm：

base.asm:

[bits 32]
[extern _start]

call _start

kernel.c：

kernel.c:

void start { char *v = (char*) 0xb8000; *v="M";}

推荐答案

第一步是修复报告的错误和警告。

The first step is to fix the reported errors and warnings.

# gcc -c kernel.c
error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘{’ token

之前预期'='，'，'，';'，'asm'或'__attribute__'它必须是

It must be

void start() { char *v = (char*) 0xb8000; *v="M";}

接下来尝试：

Next try:

# gcc -c kernel.c
warning: assignment makes integer from pointer without a cast

理解这个错误有点棘手。它抱怨 * v =M因为M是指针（指向常量字符串）。您的代码将无法按预期工作。您必须使用复制字符串或分配每个字符的函数：

Understanding this error is a bit tricky. It complains about *v="M" because "M" is a pointer (to a constant string). Your code won't work as expected. You have to use a function that copies a string or assign each character:

void start() 
{ 
    char *v = (char*)0xb8000; 
    v[0] = 'M';
    v[1] = '\0';
}

我 nasm 无处安装，所以我无法查看。



关于链接阅读文档。 -T 选项后面必须跟一个脚本文件。

I have nasm nowhere installed so I can't check it.

Regarding the linking read the documentation. The -T option requires to be followed by a script file.

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