On Jun 25, 2025, at 12:48, Bjoern A. Zeeb <bzeeb-li...@lists.zabbadoz.net> 
wrote:

> On Wed, 25 Jun 2025, Mark Millard wrote:
> 
>> Andrew Turner <andrew_at_FreeBSD.org> wrote on
>> Date: Wed, 25 Jun 2025 11:22:51 UTC :
>> 
>>> The branch main has been updated by andrew:
>>> 
>>> URL: 
>>> https://cgit.FreeBSD.org/src/commit/?id=288ba78edcfd82b4b558a46fae78e4076acbe200
>>> 
>>> commit 288ba78edcfd82b4b558a46fae78e4076acbe200
>>> Author: Andrew Turner <and...@freebsd.org>
>>> AuthorDate: 2025-06-24 16:47:28 +0000
>>> Commit: Andrew Turner <and...@freebsd.org>
>>> CommitDate: 2025-06-24 17:45:42 +0000
>>> 
>>> dev/psci: Check for functions before calling
>>> 
>>> In the SMCCC TRNG and Errata ABI drivers check if the version
>>> functions are implemented before calling them. Without this the firmware
>>> may complain about an unimplemented function being called.
>>> 
>>> Reported by: bz
>>> Reviewed by: bz
>>> Sponsored by: Arm Ltd
>>> Differential Revision: https://reviews.freebsd.org/D50978
>>> ---
>> 
>> 
>> I wonder if a debug mode or verbose mode should report
>> the != SMCCC_RET_SUCCESS cases for smccc_arch_features.
>> If this change had already been in place, the older
>> status might not have been noticed. As bz wrote
>> elsewhere:
>> 
>> "That said seems like it's still a good idea to add
>> these bits to my TF-A."
>> 
>> Having a way to check on if a TF-A instance is too
>> old to have a known status for handling things that
>> are now requested could be a good thing.
> 
> Please read the comments on the review.

If you mean the text:

QUOTE
If the firmware doesn't implement the Errata ABI then we may
enable a workaround in the kernel even if we don't need to,
e.g. when the firmware already has a workaround, or the
combination of HW means it's not needed
END QUOTE

Sometimes that might be fine. But other times updating the
TF-A may be more appropriate. Thus, sometimes one might
want to learn about which workarounds (or no-ops) are
being done because the TF-A involved does not claim to
even have a feature. Then one can consider what is
appropriate for the TF-A, possibly choosing to update
it for some of what has workarounds/no-ops in the kernel.

So, to some extent my suggestion generalizes beyond the
2 specific messages that you got and the specific changes
made for those.

It is only a suggestion, possibly not a very valuable one.

===
Mark Millard
marklmi at yahoo.com


Reply via email to