changes to make ethernet packets able to be unaligned...

Mike Silbersack silby at silby.com
Fri Mar 18 00:48:37 PST 2005


On Fri, 18 Mar 2005, John-Mark Gurney wrote:

>> I'm confused - don't sparc64 and alpha have similar alignment
>> requirements?  Why does arm require code changes?
>
> yes, the alignment constraints for arm are the same.. the reason I
> said the above is only for arm is the epe driver (which is only on
> an ARM core) has been made to use the new feature...
>
> The changes to ip_input.c will work with other drivers as well... it
> just needs to make sure that the proper defines are in amd64 and i386
> so that we don't do the fix up when we don't need to...
>
> -- 
>  John-Mark Gurney				Voice: +1 415 225 5579

Ok, I see what you're saying now, I had forgotten the #ifdef i386 sections 
we have scattered throughout the network drivers.  When I read your 
original commit, I was thinking about the transmit paths in drivers, which 
is why m_copyup made no sense to me.

Moving the alignment out of the drivers and into a common place seems like 
a good idea, but I wonder if it should be done in the ethernet code 
instead of in the ip code; won't other protocols have unaligned access 
problems if the change is made exactly as is?

Mike "Silby" Silbersack


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