Cortex-A9 SCU + ARM_ERRATA_764369
Mason
slash.tmp at free.fr
Tue Nov 3 11:52:30 PST 2015
Mark Rutland wrote:
> Mason wrote:
>
>> What is scu_base + 0x30? (SCU diagnostic control register?)
>
> It's documented (admittedly very sparsely) in the Software
> Developers Errata Notice for Cortex-A9 processors, in the
> section regarding erratum 764369.
A Freescale document mentions:
> Set bit[0] in the undocumented SCU diagnostic control register
> located at offset 0x30 from the PERIPHBASE address. Setting this bit
> disables the "migratory bit" feature. This forces a dirty cache line
> to be evicted to the lower memory subsystem—which is both the point
> of coherency and the point of unification—when it is being read by
> another processor.
Can this register be written to by a non-secure OS?
Regards.
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