Re: [PATCH] 64-bit struct resource fields

Eric W. Biederman (ebiederm@xmission.com)
01 Dec 2002 21:46:11 -0700


Dave Hansen <haveblue@us.ibm.com> writes:

> We need some way to replicate the e820 tables for kexec. This modifies struct
> resource to use u64's for its start and end fields. This way we can export the
> whole e820 table on PAE machines.
>
> resource->flags seems to be used often to mask out things in
> resource->start/end, so I think it needs to be u64 too.

I don't see this in the parts of the kernel your patch changes, I will
have to look a little more and see if this is really true. If it
is you probably should append ULL to the flag constants.

>But, Is it all right to
>
> let things like pcibios_update_resource() truncate the resource addresses like
> they do?

The type of addresses for resources will always be equal or larger
than the resources they actually represent. Until someone modifies
the pcibios_xxxx code to handle 64bit BARs it should only be
truncation of zeros and thus safe.

I will see if I can scrutinize this carefully, and try it in the next
little while. For now I am placing it on the back burner and going
to bed. It looks like a good start though.

Eric
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