linux-kernel - Re: [PATCH 0/3] minor cleanups to EFLAGS initialisation in ret_from

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Date:	Wed, 10 Aug 2011 17:35:21 +0200
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Ian Campbell <Ian.Campbell@...citrix.com>
Cc:	Cyrill Gorcunov <gorcunov@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Pekka Enberg <penberg@...nel.org>,
	Andi Kleen <ak@...ux.intel.com>, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH 0/3] minor cleanups to EFLAGS initialisation in
 ret_from_fork

On Wed, 2011-08-10 at 16:27 +0100, Ian Campbell wrote:
> raw_spin_unlock_irq unconditionally re-enables interrupts so I don't
> really see what I've changed since interrupts are enabled by
> schedule_tail and I've moved (on 64 bit) the EFLAGS reset to after
> schedule_tail, so it should have interrupts enabled at that point
> already and so they should remain enabled. Or are you suggesting that
> things were already wrong?

Ah, I thought this was about the EFLAGS state of new tasks which would
get into effect at switch_to(), which is well before we enable
interrupts in finish_lock_switch().

> However I've switched the order of my second patch anyway, so EFLAGS is
> reset to 0x0002 (interrupts disabled) on both 32- and 64-bit before the
> call to schedule_tail, since it does seem like the simpler option. I'll
> repost shortly. 

OK.
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