Kexec on arm64

[Geoff Levand]

Hi Arun,

On Wed, 2014-08-13 at 16:39 +0530, Arun Chandran wrote:
> I have one more concern regarding flushing of D-cache area corresponding
> to the kexec_list entrees.
> 
> Currently kexec_list_walk() is doing
> 
> 1) flush_dcache_area of the kexec_list[0] till PAGE_SIZE
> 
> 2) continue accessing entries in kexec_list[0] to PAGE_SIZE
> 
> 3) switch to next kexec_list depending upon kexec_list[entry] & flag
> ==  IND_INDIRECTION
> 
> 4) goto 1
> 
> Shouldn't that be doing flush_dcache_area() after completely using the list??

We just want to get any data in the dcache out to the PoC before
disabling the dcache, so as long as there are only reads, and no writes
to those addresses, kexec_list_walk() should work OK.

I will move the flush of the new kernel image to after it is copied in
relocate_new_kernel().  I think that your L3 cache may not work with
what we have now:

  current:  invalidate dcache -> turn off dcache -> write data to PoC
  proposed: turn off dcache -> write data to PoC -> invalidate dcache

-Geoff