[coreboot] Patch merged into coreboot/master: c35c461 Invalidate cache before first jump

[Marc Jones]

On Tue, Apr 10, 2012 at 5:29 AM, Bao, Zheng <Zheng.Bao at amd.com> wrote:
> I tried. It behaves as bad as wbinvd does.
>
> Joe
>
>> -----Original Message-----
>> From: Andrew Goodbody [mailto:ajg4tadpole at gmail.com]
>> Sent: Tuesday, April 10, 2012 7:04 PM
>> To: Bao, Zheng
>> Cc: 'Marc Jones'; Marc Jones; 'coreboot at coreboot.org'
>> Subject: Re: [coreboot] Patch merged into coreboot/master: c35c461
>> Invalidate cache before first jump
>>
>> On 09/04/12 04:24, Bao, Zheng wrote:
>> > Hi,
>> > It is unstable. In most cases, it hangs at this wbinvd. Once it pass
>> that instruction, it will hang at when AP cores are launched.
>>
>> Try invd instead of wbinvd. There should be no need to preserve
>> anything
>> from the cache so the write back is not needed. The write back may also
>> need functional memory which will not be there at least from power on.
>> Also note that these instructions are 486+ only.
>>
>> Andrew



An wbind/invd by the APs may to cause problems with CAR. I think that
the coherency rules will cause a wbind on all cores, but I am not
positive.

Stefan, can you explain the requirement or consider how else to only
do this on a processor that requires it?

Marc



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