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Date: Sat, 01 Feb 2014 12:16:43 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Linus Torvalds <torvalds@linux-foundation.org>
CC: Suresh Siddha <sbsiddha@gmail.com>,
	Nate Eldredge <nate@thatsmathematics.com>,
	Thomas Gleixner <tglx@linutronix.de>,
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	Jan Kara <jack@suse.cz>, George Spelvin <linux@horizon.com>,
	Pekka Riikonen <priikone@iki.fi>
Subject: Re: [PATCH] Make math_state_restore() save and restore the interrupt
 flag
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On 02/01/2014 11:46 AM, Linus Torvalds wrote:
> 
> .. which *does* actually bring up something that might work, and might
> be a good idea: remove the "restore math state or set TS" from the
> normal kernel paths *entirely*, and move it to the "return to user
> space" phase.
> 

The task switch code would have to be aware in case of preemption,
though.  The nice thing about *that* is that we could probably
completely drop the notion that we can't preempt an FPU-using kernel task.

	-hpa