linux-kernel - Re: Got FPU related warning on Intel Quark during boot

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Date:	Thu, 10 Mar 2016 17:15:15 +0000
From:	Bryan O'Donoghue <pure.logic@...us-software.ie>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Andy Shevchenko <andy.shevchenko@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Fenghua Yu <fenghua.yu@...el.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Oleg Nesterov <oleg@...hat.com>,
	"Yu, Yu-cheng" <yu-cheng.yu@...el.com>
Subject: Re: Got FPU related warning on Intel Quark during boot

On Thu, 2016-03-10 at 17:49 +0100, Borislav Petkov wrote:
> On Thu, Mar 10, 2016 at 03:45:21PM +0000, Bryan O'Donoghue wrote:
> > It works but user-space FPU is broken; something's wrong with the
> > initial state of the FPU regs - it looks as though they aren't
> > being
> > properly initialized and FPU context in the signal handler is wrong
> > too.
> 
> What does your test prog say when you boot linux-next with
> "eagerfpu=off" and *without* my fix?
> 

root@...ileo:~# ./fpu 
f is 10.000000 g is 10.100000
Double value is 0.000000
Double value is 0.100000
Double value is 0.200000
^Chandler value of variable is 0.300000
Double value is 0.300000
Double value is 0.400000
^Z
[1]+  Stopped                 ./fpu
root@...ileo:~#