linux-kernel - Re: [PATCHv4] arm: Preserve the user r/w register TPIDRURW on context switch and fork

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Message-ID: <51979801.7010903@dawncrow.de>
Date:	Sat, 18 May 2013 17:02:25 +0200
From:	André Hentschel <nerv@...ncrow.de>
To:	"linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
CC:	Russell King - ARM Linux <linux@....linux.org.uk>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	Will Deacon <will.deacon@....com>,
	Jonathan Austin <jonathan.austin@....com>
Subject: Re: [PATCHv4] arm: Preserve the user r/w register TPIDRURW on context
 switch and fork

Am 08.05.2013 21:03, schrieb André Hentschel:
> From: =?UTF-8?q?Andr=C3=A9=20Hentschel?= <nerv@...ncrow.de>
> 
> Since commit 6a1c53124aa1 the user writeable TLS register was zeroed to
> prevent it from being used as a covert channel between two tasks.
> 
> There are more and more applications coming to WinRT, Wine could support them,
> but mostly they expect to have the thread environment block (TEB) in TPIDRURW.
> 
> This patch preserves that register per thread instead of clearing it.
> Unlike the TPIDRURO, which is already switched, the TPIDRURW
> can be updated from userspace so needs careful treatment in the case that we
> modify TPIDRURW and call fork(). To avoid this we must always read
> TPIDRURW in copy_thread.
> 
> Signed-off-by: André Hentschel <nerv@...ncrow.de>
> Signed-off-by: Will Deacon <will.deacon@....com>
> Signed-off-by: Jonathan Austin <jonathan.austin@....com> 
> 

Hi,
I'm not yet very familiar with the development process here,
am i getting no feedback on v4 because of the mergewindow being closed?
Or is there another reason? Sry for being impatient.
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