Re: [PATCH v3 3/4] arm64: mte: Enable async tag check fault

[Vincenzo Frascino]

On 1/18/21 2:48 PM, Vincenzo Frascino wrote:
>> Are you aware of cases where the TFSR_EL1 value is read other than by an
>> MRS? e.g. are there any cases where checks are elided if TF1 is set? If
>> so, we may need the ISB to order the direct write against subsequent
>> indirect reads.
>>
> Thank you for the explanation. I am not aware of any case in which TFSR_EL1 is
> read other then by an MRS. Based on the ARM DDI 0487F.c (J1-7626) TF0/TF1 are
> always set to '1' without being accessed before. I will check with the
> architects for further clarification and if this is correct I will remove the
> isb() in the next version.
> 

I spoke to the architects and I confirm that the isb() can be removed.

-- 
Regards,
Vincenzo