Re: pentium 4MB pages question for you MMU hackers

Morgan Sarges (
Fri, 03 Jan 1997 19:52:23 +0000

Ingo Molnar wrote:
> just wondering if ring 3 code could use 4MB pages.
> When i have the following page dir entry:
> _PAGE_TABLE | _PAGE_4M | 4mb_aligned_phys_addr
> Kernel space sees phys_addr correctly, but user space doesnt. Does this
> mean that 4MB pages are only for ring0 code? Has anyone experimented with
> this one?
> [heh, if only for ring0 then one more argument for GGI being in the kernel
> .. and one more argument for ring0 processes]
> -- mingo
> ps. and i got faults when phys_addr wasnt 4mb aligned ... does it really
> have to be 4mb aligned?

Id like to ask a dumb question here, before I say something really

What is ring0 code? How does it relate to linux/unix?

What are GGI's?

If ring0 is what I think it is, this could make 1997 very long and ugly.

Morgan Sarges			Warbirds: blip