[Linux-Xtensa] Re: Cache flushing when transitioning from U-Boot to Kernel

Chris Zankel chris at zankel.net
Thu Jul 11 19:47:58 PDT 2013


Hi Max,

On 07/11/2013 07:30 PM, Max Filippov wrote:
> Hi Chris,
>
> AFAIK ARM and some exotic arches start with caches disabled and
> initialize them in boot/compressed/head.S
Actually, now that you mentioned it, some arches do indeed flush the
cache in u-boot (and disable it). Thanks for pointing me in the right
direction!
>> anything in the kernel? In cases where we (re-) initialize the MMU, we
>> probably need to flush the caches before messing with the MMU?
> Looks like we can move cache unlock+invalidation to reset vector and
> do nothing in kernel/head.S
Looking at the older u-boot, we also did flush the caches, so I'll just
add that functionality back.

Sorry for the fuzz.

Thanks,
-Chris


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