Re: Is e820_setup_gap broken ??

From: Alok Kataria
Date: Fri Jun 20 2008 - 14:26:09 EST


On Fri, 2008-06-20 at 11:14 -0700, Alok Kataria wrote:
> I am looking at the e820_setup_gap function in tip/master tree.
>
> For i386 if we don't find a big enough gap in e820 map, we keep the
> gapstart value to "0x10000000". Don't print any warning messages for the
> user that we were unable to find gap in the 32bit address range.
>
> Now this address 0x10000000 can actually be used by the system ram or
> may have been reserved for some reason. Wouldn't the system break if the
> PCI devices started using this gap in such a case ?

Ok I take this back.
In the PCI code path when we actually use this gap start address for
allocating the resource...allocate_resource will shout about the memory
address being already in use. And the pci device won't be allocated
which is the right thing to do.


> Also note that this is not just a problem with the tip/master tree in
> the current mainline tree too we do similar stuff for i386 kernel.
>
> Thanks,
> Alok

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