OSDev.org

Posted: **Fri Mar 14, 2014 4:29 am**

(I apologize for my english since it is not my mother-tongue)

Hi everyone,

Following this tutorial (http://wiki.osdev.org/64-bit_Higher_Hal ... ith_GRUB_2) in order to write my own OS, I encounter a weird bug.
As soon as I add global (static or not) variables in my C code, the assembly bootstrap can't reach the C main() function. The system restarts.

I tried with only the code given by the tutorial, simply changing the c code from:

Code: Select all

int main()
{
	while (1);
}

to:

Code: Select all

int a;
int b[20];
int main()
{
	while (1);
}

NB: the a and b symbols appears to be in the .bss section. If the "static" keyword is added it is no more the case, but the kernel keeps crashing.

I think it is a kind of global symbols mismatch when GRUB2 loads the ELF64 file, but I still can't figure out what is wrong since I am not an expert in the ELF64 format.

Posted: **Fri Mar 14, 2014 5:16 am**

I think you missed the most important part of the page:

the factual accuracy of this article is disputed

IOW, if you want to get something done, it's best if you tried something else first.

OSDev.org

Global variable and 64 bits higher half kernel with GRUB2

Global variable and 64 bits higher half kernel with GRUB2

Re: Global variable and 64 bits higher half kernel with GRUB