[PATCH 1/9] ARM: enable secure platform-only erratas

[Dmitry Osipenko]

On 20.12.2017 02:28, Russell King - ARM Linux wrote:
> On Thu, Oct 05, 2017 at 09:16:12PM +0300, Dmitry Osipenko wrote:
>> On 20.07.2017 03:29, Michał Mirosław wrote:
>>> Allow secure-only erratas to be used in multiarch kernel.
>>>
>>> Signed-off-by: Michał Mirosław <mirq-linux at rere.qmqm.pl>
>>> ---
>>>  arch/arm/Kconfig | 20 ++++++++++++++------
>>>  1 file changed, 14 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>>> index a208bfe367b5..a1eff866550b 100644
>>> --- a/arch/arm/Kconfig
>>> +++ b/arch/arm/Kconfig
>>> @@ -696,6 +696,14 @@ config ARCH_MULTI_CPU_AUTO
>>>  
>>>  endmenu
>>>  
>>> +config ARCH_ASSUME_SECURE_PLATFORM
>>> +	bool "Enable ERRATAs using secure-only registers"
>>> +	default !ARCH_MULTIPLATFORM
>>
>> I think default should always be "Yes" and this option shouldn't affect
>> multiplatform kernels. So a multiplatform kernel wouldn't be an option
>> for your device.
> 
> No, that changes the current behaviour.
> 
> Current behaviour is for the secure-only errata to be disabled when the
> multi-platform option is enabled, because multi-platform kernels have to
> be able to run in the non-secure world.  Defaulting this option to "yes"
> means that these errata become visible.

Indeed, I got it inverted.

> I have to wonder why you need this though - your patches seem to be
> targetting a platform that runs in non-secure world, and enabling these
> errata would make the kernel non-bootable on your platform.

Perhaps because Michał made the Tegra's CPU reset handler hardcoded to either
secure or to non-secure case based on the kernels configuration. I've showed how
we can get rid of that inflexibility in [0], maybe Michał could pick up the idea
in the next iteration of the patches.

[0] https://marc.info/?l=linux-tegra&m=151371042522835