RE: [PATCH v3 0/8] gdbserver improvements for AArch64 SVE support

Willgerodt, Felix
2024-05-07T14:30:26Z

> -----Original Message-----
> From: Gdb-patches <gdb-patches-
> bounces+felix.willgerodt=intel.com@sourceware.org> On Behalf Of Thiago Jung
> Bauermann via Gdb-patches
> Sent: Montag, 30. Januar 2023 05:45
> To: gdb-patches@sourceware.org
> Cc: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Subject: [PATCH v3 0/8] gdbserver improvements for AArch64 SVE support
>
> Hello,
>
> This is version 3 of the patch series adding support to gdbserver for
> inferiors that change the SVE vector length at runtime. This is already
> supported by GDB, but not by gdbserver. Version 2 was posted here:
>
> https://inbox.sourceware.org/gdb-patches/20221126020452.1686509-1-
> thiago.bauermann@linaro.org/
>
> This version incorporates the review comments from v2 (thanks!). The
> biggest change is that it implements Simon's idea¹:
>
> > If it's the case, that we need to extend the RSP to allow fetching
> > per-thread tdesc, here's the idea I had in mind for a while, to avoid
> > adding too much overhead. Stop replies and the qXfer:threads:read reply
> > could include a per-thread tdesc identifier. That tdesc identifier
> > would be something short, either an incrementing number, or some kind of
> > hash of the tdesc. It would be something opaque chosen by the stub. A
> > new packet would be introduced to allow GDB to request the XML given
> > that ID. On the GDB side, GDB would request the XML when encountering a
> > tdesc ID it doesn't know about, and then cache the result.
>
> The only difference from the above in this series is that instead of
> creating a new packet to allow GDB to request the XML given the ID, I'm
> extending the qXfer:features:read request: GDB can send "target-id-%u.xml"
> as the annex, where %u is the target description ID. Please let me know if
> you think a separate packet would be better. The remote protocol changes
> are documented in patch 5.
>
> I had to drop the Reviewed-by tags from some patches because they have some
> significant changes from the version that was reviewed.
>
> There's also a new testcase exercising the case of an inferior's thread
> changing its SVE vector length. The previous version of this series failed
> the testcase, but this one passes it.
>
> With this series applied, gdb.arch/aarch64-sve.exp passes all tests on
> extended-remote aarch64-linux. Without them, it fails tests after the
> testcase changes the vector length.
>
> Tested on native and extended-remote aarch64-linux, x86_64-linux and
> armv7l-linux-gnueabihf (the last one on QEMU TCG).
>
> ¹ https://inbox.sourceware.org/gdb-patches/559069a3-f3ce-2059-bf4a-
> 44add43979f7@simark.ca/

Hi Thiago, Hi Luis,

I wonder what happened to this series. Do you plan to revive it at some
point? I realise this isn't an easy series to land. Tough it would be great
to have in my view.

Regards,
Felix

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