[PATCH v4 16/20] arm64: enable Permission Indirection Extension (PIE)

[Marc Zyngier]

On 2023-06-20 20:16, Neil Armstrong wrote:
> Hi Joey,
> 
> On 06/06/2023 16:58, Joey Gouly wrote:
>> Now that the necessary changes have been made, set the Permission 
>> Indirection
>> registers and enable the Permission Indirection Extension.
>> 
>> Signed-off-by: Joey Gouly <joey.gouly at arm.com>
>> Cc: Catalin Marinas <catalin.marinas at arm.com>
>> Cc: Will Deacon <will at kernel.org>
>> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
> 
> This patch on linux-next causes a great amount of:
> 
> X     xxx.xxxxxx Emulated RAZ for ID register: ISS 0x36002f
> 
> messages printed by the system firmware on the Qualcomm SM8550 SoC,
> and the platform is barely usable.

As others have said on this thread, this is a firmware bug.
Not a lot we can do about that, unfortunately, apart from hiding
the new feature behind a config option that you'd disable on this
platform.

Alternatively, disabling idle management on this machine should
reduce the screaming greatly.

         M.
-- 
Jazz is not dead. It just smells funny...