[ros-dev] multiboot.S patch in need of review, please

[Alex Ionescu]

Royce Mitchell III wrote:

> I was in a strange mood and decided to try to implement something Alex 
> wanted.

=)

>
> I've done the leg-work on this, but need someone familiar with boot-up 
> and particularly smp to review this patch. I do not have access to 
> smp, and do not wish to break it.
>
> This patch implements the /3G switch from within multiboot.S, which is 
> necessary in order to configure the page tables correctly.
>
> I noticed some code in _main() that was processing a 3G switch on the 
> command-line, and I can't understand how it could possibly work 
> because it's not readjusting the page tables, nor does it transition 
> to the 0xC0000000 address space that I can see, so I don't think that 
> code actually works. If it does, I'm glad to be proved wrong.

I added it, simply to see how ntoskrnl would work with dynamic address.

>
> The patch I've written makes an assumption that lowmem is available 
> when application processors execute the code. I can't seem to figure 
> out how or where the application processor(s) actually get told to 
> start executing, so I don't know if this assumption is true. However, 
> if it's not true, if someone could point me to the code that inits the 
> application processors, I can configure them to pass the needed info 
> via %ebp or something.
>
> Finally, I haven't actually tried booting this code. I wanted someone 
> to review it first for obvious blunders, or to tell me, if necessary, 
> that I've wasted my time ;)    If I'm on the right track then, when 
> I'm feeling motivated enough again, I will actually try booting it.
>
>  
>
I'll test it on qemu...can't vouch for smp though.

If it works I'll get to work on relocation when I get back home.


Best regards,
Alex Ionescu