Date: Wed, 22 Mar 2006 13:45:56 -0800
From: Chris Wright <chrisw@sous-sol.org>
To: Zachary Amsden <zach@vmware.com>
Cc: Chris Wright <chrisw@sous-sol.org>, linux-kernel@vger.kernel.org,
       xen-devel@lists.xensource.com, virtualization@lists.osdl.org,
       Ian Pratt <ian.pratt@xensource.com>,
       Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Subject: Re: [RFC PATCH 19/35] subarch support for control register accesses
Message-ID: <20060322214556.GK15997@sorel.sous-sol.org>
References: <20060322063040.960068000@sorel.sous-sol.org> <20060322063754.391952000@sorel.sous-sol.org> <442110F0.9090805@vmware.com>
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* Zachary Amsden (zach@vmware.com) wrote:
> Chris Wright wrote:
> >+#define read_cr4_safe() ({			      \
> >+	unsigned int __dummy;			      \
> >+	/* This could fault if %cr4 does not exist */ \
> >+	__asm__("1: movl %%cr4, %0		\n"   \
> >+		"2:				\n"   \
> >+		".section __ex_table,\"a\"	\n"   \
> >+		".long 1b,2b			\n"   \
> >+		".previous			\n"   \
> >+		: "=r" (__dummy): "0" (0));	      \
> >+	__dummy;				      \
> >+})
> 
> I think you'll find trap and emulate quite sufficient for this one.

Heh ;-)

> >+#define stts() write_cr0(8 | read_cr0())
> >  
> 
> Nit: You shouldn't need to redefine stts() in the subarch.

Yes, you're right, better to keep things consolidated.
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