Re: [RFC PATCH 0/5] gdb/aarch64: Support for FPMR

[Thiago Jung Bauermann <thiago.bauermann@linaro.org>]

Ezra Sitorus <ezra.sitorus@arm.com> writes:

>> Hello Ezra,
>
> Hi!
>
>> Thank you for these patches.
>> 
>> <Ezra.Sitorus@arm.com> writes:
>> 
>> > From: Ezra Sitorus <ezra.sitorus@arm.com>
>> >
>> > The Floating Point Mode Register (FPMR) determines the behaviour of FP8
>> > instructions. This patch series adds support for this register into gdb.
>> >
>> > This has been tested using Shrinkwrap, which allows me to run Linux on a
>> > model of an Arm system with new features. You can find more information
>> > here: [1].
>> 
>> Is there something specific one has to do to enable FPMR on
>> Shrinkwrap/FVP?
>> 
>> I tried building an Armv9.5 configuration:
>> 
>> $ shrinkwrap build --overlay=arch/v9.5.yaml ns-edk2.yaml
>> 
>> and then running it with upstream kernel v6.16-rc7 which I think should
>> support FPMR, but AT_HWCAP doesn't have the FPMR bit set, and the test
>> program from the allow_aarch64_fpmr_tests procedure gets a SIGILL so the
>> testcases in this series report unsupported.
>> 
>> -- 
>> Thiago
>
> I think that kernel version is fine. To get FPMR to work, I created an overlay.yaml
> file which contains this:
>
> run:
>   params:
>     -C cluster0.has_fpmr: 1
>
> Then I run with this:
>
> shrinkwrap run ns-edk2.yaml --overlay overlay.yaml

Thanks! This worked.

> FYI, if you want to enable other features, you can see the options by doing:
>
> docker exec <docker container name> FVP_Base_RevC-2xAEMvA --list-params

This is very useful. Thanks for the tip.

-- 
Thiago