From: Rik van Riel <riel@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Andrew Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH RFC 2/5] x86,fpu: delay FPU register loading until switch to userspace
Date: Sat, 01 Oct 2016 20:42:36 -0400 [thread overview]
Message-ID: <1475368956.21644.15.camel@redhat.com> (raw)
In-Reply-To: <CALCETrWnhA4Gd5AxDEJz7d-VQNDN7O8ayyna7fz3=HNtNnARxQ@mail.gmail.com>
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On Sat, 2016-10-01 at 16:44 -0700, Andy Lutomirski wrote:
> On Sat, Oct 1, 2016 at 1:31 PM, <riel@redhat.com> wrote:
> >
> >
> > +static inline void switch_fpu_finish(void)
> > {
> > + set_thread_flag(TIF_LOAD_FPU);
> > }
>
> I can imagine this causing problems with kernel code that accesses
> current's FPU state, e.g. get_xsave_field_ptr().
That makes me wonder, what test programs do people have
to verify the correctness of the FPU switching code?
I have a few floating point benchmarks that check
the results for correctness, but nothing that adds in
signals, for example.
What do people use?
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next prev parent reply other threads:[~2016-10-02 0:42 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-01 20:31 [PATCH RFC 0/5] x86,fpu: make FPU context switching much lazier riel
2016-10-01 20:31 ` [PATCH RFC 1/5] x86,fpu: split prev/next task fpu state handling riel
2016-10-01 23:26 ` Andy Lutomirski
2016-10-02 0:02 ` Rik van Riel
2016-10-01 20:31 ` [PATCH RFC 2/5] x86,fpu: delay FPU register loading until switch to userspace riel
2016-10-01 23:44 ` Andy Lutomirski
2016-10-02 0:08 ` Rik van Riel
2016-10-03 20:54 ` Andy Lutomirski
2016-10-03 21:21 ` Rik van Riel
2016-10-03 21:36 ` Andy Lutomirski
2016-10-04 1:29 ` Rik van Riel
2016-10-04 2:09 ` Andy Lutomirski
2016-10-04 2:47 ` Rik van Riel
2016-10-04 3:02 ` Andy Lutomirski
2016-10-04 6:35 ` Ingo Molnar
2016-10-04 12:48 ` Rik van Riel
2016-10-04 2:11 ` Rik van Riel
2016-10-04 3:02 ` Andy Lutomirski
2016-10-02 0:42 ` Rik van Riel [this message]
2016-10-03 16:23 ` Dave Hansen
2016-10-01 20:31 ` [PATCH RFC 3/5] x86,fpu: add kernel fpu argument to __kernel_fpu_begin riel
2016-10-01 20:31 ` [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded riel
2016-10-03 20:04 ` Dave Hansen
2016-10-03 20:22 ` Rik van Riel
2016-10-03 20:49 ` Dave Hansen
2016-10-03 21:02 ` Rik van Riel
2016-10-01 20:31 ` [PATCH RFC 5/5] x86,fpu: kinda sorta fix up signal path riel
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