Re: [Bug] 2.6.18-rc6-mm2 i386 trouble finding RSDT in get_memcfg_from_srat

[Vivek Goyal <vgoyal@in.ibm.com>]

On Thu, Sep 14, 2006 at 04:21:33PM -0700, Dave Hansen wrote:
> On Thu, 2006-09-14 at 19:04 -0400, Vivek Goyal wrote:
> > I think I know what is going on wrong here. boot_ioremap() is assuming 
> > that only first 8MB of physical memory is being mapped and while
> > calculating the index into page table (boot_pte_index) we will truncate
> > any higher address bits. 
> 
> Vivek, are those pte pages still all contiguous?
> 

Yes, they are. (arch/i386/kernel/head.S)

> Yeah, that's probably it.  Keith, I'm trying to think of reasons why we
> need the mask here:
> 
> #define boot_pte_index(address) \
>              (((address) >> PAGE_SHIFT) & (BOOT_PTE_PTRS - 1))
> 
> and I can't think of any other than just masking out the top of the
> virtual address.  You could do this a bunch of other ways, like __pa().
> 
> This might just work:
> 
> static unsigned long boot_pte_index(unsigned long vaddr)
> {
> 	return __pa(vaddr) >> PAGE_SHIFT;
> }
>

This looks good. Should work.

Thanks
Vivek