Subject: Re: [PATCH 2/2] selftests: vm: pkeys: Fix powerpc access right updates

From: Sandipan Das <[email-masked]>
Date: Sat, 9 May 2020 01:24:26 +0530

Hi Florian,

On 08/05/20 11:31 pm, Florian Weimer wrote:
> * Sandipan Das:
> 
>> The Power ISA mandates that all writes to the Authority
>> Mask Register (AMR) must always be preceded as well as
>> succeeded by a context-synchronizing instruction. This
>> applies to both the privileged and unprivileged variants
>> of the Move To AMR instruction.
> 
> Ugh.  Do you have a reference for that?
> 
> We need to fix this in glibc.
> 

This is from Table 6 of Chapter 11 in page 1134 of Power
ISA 3.0B. The document can be found here:
https://ibm.ent.box.com/s/1hzcwkwf8rbju5h9iyf44wm94amnlcrv

- Sandipan