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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@kernel.org>,
	"Bryan O'Donoghue" <pure.logic@nexus-software.ie>,
	Andy Lutomirski <luto@amacapital.net>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	Fenghua Yu <fenghua.yu@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Oleg Nesterov <oleg@redhat.com>,
	"Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Subject: Re: [PATCH] x86/FPU: Fix FPU handling on legacy FPU machines
Date: Fri, 11 Mar 2016 10:32:43 -0800	[thread overview]
Message-ID: <CA+55aFyHQ0+zM5pBNWakA_ti4gutLX5VdounyuduGeFGTmvksg@mail.gmail.com> (raw)
In-Reply-To: <20160311113206.GD4312@pd.tnic>

On Fri, Mar 11, 2016 at 3:32 AM, Borislav Petkov <bp@alien8.de> wrote:
> 486 cores like Intel Quark support only the very old, legacy x87 FPU
> (FSAVE/FRSTOR, CPUID bit FXSR is not set). And our FPU code wasn't
> handling the saving and restoring there properly. First, Andy Shevchenko
> reported a splat:
>
>   WARNING: CPU: 0 PID: 823 at arch/x86/include/asm/fpu/internal.h:163 fpu__clear+0x8c/0x160
>
> which was us trying to execute FXRSTOR on those machines even though
> they don't support it.
>
> After taking care of that, Bryan O'Donoghue reported that a simple FPU
> test still failed because we weren't initializing the FPU state properly
> on those machines.

Obvious Ack to the patch, along with a "how did this ever work
before?" comment..

           Linus

  reply	other threads:[~2016-03-11 18:32 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-10 10:46 Got FPU related warning on Intel Quark during boot Andy Shevchenko
2016-03-10 11:19 ` Ingo Molnar
2016-03-10 12:48   ` Andy Shevchenko
2016-03-10 12:56     ` Borislav Petkov
2016-03-10 13:31       ` Andy Shevchenko
2016-03-10 14:59         ` Borislav Petkov
2016-03-10 15:22           ` Andy Shevchenko
2016-03-10 15:45             ` Bryan O'Donoghue
2016-03-10 16:49               ` Borislav Petkov
2016-03-10 17:15                 ` Bryan O'Donoghue
2016-03-10 19:06                   ` Borislav Petkov
2016-03-11  1:31               ` Andy Lutomirski
2016-03-11 10:50                 ` Bryan O'Donoghue
2016-03-11  1:39           ` Andy Lutomirski
2016-03-11  9:08             ` Ingo Molnar
2016-03-11  9:48               ` Borislav Petkov
2016-03-11 11:02                 ` Bryan O'Donoghue
2016-03-11 11:26                   ` Borislav Petkov
2016-03-11 11:32                     ` [PATCH] x86/FPU: Fix FPU handling on legacy FPU machines Borislav Petkov
2016-03-11 18:32                       ` Linus Torvalds [this message]
2016-03-11 22:03                         ` Borislav Petkov
2016-03-11 22:07                           ` Dave Hansen
2016-03-11 22:20                             ` Borislav Petkov
2016-03-12 17:21                               ` Andy Lutomirski
2016-03-12 17:47                                 ` Borislav Petkov
2016-03-12 12:04                           ` Bryan O'Donoghue
2016-03-12 12:27                             ` Borislav Petkov
2016-03-12 15:17                           ` Ingo Molnar
2016-03-22 22:03                           ` Maciej W. Rozycki
2016-03-12 15:08                         ` Ingo Molnar
2016-03-12 15:12                           ` Ingo Molnar
2016-03-12 15:16                       ` [tip:x86/urgent] x86/fpu: Fix eager-FPU " tip-bot for Borislav Petkov

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