[coreboot] [PATCH] LAR: Don't clobber top 8 bytes

Jordan Crouse jordan at cosmicpenguin.net
Wed Dec 3 19:00:10 CET 2008

Carl-Daniel Hailfinger wrote:
> On 03.12.2008 12:48, Stefan Reinauer wrote:
>> Carl-Daniel Hailfinger wrote:
>>> LAR currently overwrites the top 13 bytes (0xfffff3-0xffffff) of the
>>> bootblock with zeros, then it stores the ROM size in 0xfffff4-0xfffff7.
>>> The top 8 bytes are unused in that scheme.
>>> Leave the top 8 bytes as they are and allow us to store something in
>>> there during the bootblock build process. The byte at 0xfffff3 is 0xff
>>> by default on x86 and setting it to 0 is not needed.
>>> Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
>> Nack.
>> They're unused, and until they are used, they should be cleared to a
>> consistent state.
> They are already cleared by arch/x86/stage0_common.S. Having to clear
> them in the LAR would mean the code in stage0_common.S is crap and needs
> to be fixed.

Not necessarily.  This is a userland utility, so there is no real 
penalty for making extra sure that the area is in a valid state.  LAR 
shouldn't depend on the v3 code to do the right thing, nor should the v3 
code depend on LAR to do the right thing.


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