[Dri-devel] PPC Lockup (ati-pcigart-branch)

[Roman Zippel]

Hi,

On Mon, 22 Jan 2001, Michel Dänzer wrote:

> > There is no pte table and so there is nothing mapped at that address, you
> > can use (pgd|pmd|pte)_present() to test for that.
>
> You are saying we should use *_present() to check each of these before using
> *_offset to get the pointer? And what if *_present() is false?

It depends what you what you want to do. If you just want to do a reverse
lookup, yes, you have to check the value with *_present.
But you can also map something at that address, then you had to use
*_alloc(), but leave that better to ioremap/vmalloc. (Look for map_page in
arch/ppc/mm/init.c for how it can be done.)

bye, Roman


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