linux-kernel - Re: [GIT PULL] x86 FPU changes for 5.2

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Message-ID: <20190507215925.3wfs7mia5aesedr2@linutronix.de>
Date:   Tue, 7 May 2019 23:59:26 +0200
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Borislav Petkov <bp@...e.de>, Rik van Riel <riel@...riel.com>,
        x86-ml <x86@...nel.org>, lkml <linux-kernel@...r.kernel.org>
Subject: Re: [GIT PULL] x86 FPU changes for 5.2

On 2019-05-07 10:35:25 [-0700], Linus Torvalds wrote:
> Has this gone through lots of testing, particularly with things like
> FP signal handling and old machines that don't necessarily have
> anything but the most basic FP state (ie Pentium class etc)?

I tried it in qemu with incremental FPU capabilities so it went through
all the possible load/restore variants during signal handling. I had a
testcase which did SHA1 computation and a received a SIGALRM every
second. This caught some bugs, most of them were xsave/xsaves related
once the SHA1 result did not match. I tried something similar one the
8087 FPU.
I had the series in the v5.0-RT tree which resulted in the most recent
patch in that branch.

>                Linus

Sebastian