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I am working on trying to implement paging into my operating system. I was currently trying to use position independent code to relocate my kernel in the assembly stub and then initalize paging in c from the kernel.

I am having problems with trying to do this and was wondering if I can relocate my kernel in the setup of the paging code?

If this is possible, are there any problems to doing this. I have thought of using the GDT trick for reloating the kernel also, but I cannot figure out how to code it. Has anybody had any luck in setting up this method?

why not simply enabling the paging at the assembly stub (which can be made position-independent quite easily, imho) so that you don't have to bother with relocation (as the run-time base address of the kernel will be known at compile-time , nor with PIC in the kernel ?

I agree with Pype on this one. In my 'big' Mobius kernel, I use the GDT trick to put the kernel image at C000_0000 even with paging disabled, then I enable paging and everything is normal. In some more recent experimental kernels I've been enabling paging right at the start, with assembler code to set up the initial mappings (0000_0000..0040_0000 and C000_0000..C040_0000). It's a bit nastier than doing it in C, but you only have to do it once, and you don't have to write position-independent C code.

I agree with Pype on this one. In my 'big' Mobius kernel, I use the GDT trick to put the kernel image at C000_0000 even with paging disabled, then I enable paging and everything is normal. In some more recent experimental kernels I've been enabling paging right at the start, with assembler code to set up the initial mappings (0000_0000..0040_0000 and C000_0000..C040_0000). It's a bit nastier than doing it in C, but you only have to do it once, and you don't have to write position-independent C code.

I would like to take a look at this code, would you be kind to post it?

See the attached startup code. It expects a Multiboot loader and should be fairly generic. Note that the initial page directory and the two initial page tables are put in a separate section in the executable, so that they can be page-aligned via the linker script.

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