From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] Hibernation: Document __save_processor_state() on x86-64
Date: Sun, 30 Dec 2007 22:04:56 +0100
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Cc: pm list <linux-pm@lists.linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>, Len Brown <lenb@kernel.org>,
       LKML <linux-kernel@vger.kernel.org>, Pavel Machek <pavel@suse.cz>
References: <200712281353.37976.rjw@sisk.pl> <20071230142109.GK16946@elte.hu>
In-Reply-To: <20071230142109.GK16946@elte.hu>
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On Sunday, 30 of December 2007, Ingo Molnar wrote:
> 
> * Rafael J. Wysocki <rjw@sisk.pl> wrote:
> 
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> > 
> > Document the fact that __save_processor_state() has to save all CPU 
> > registers referred to by the kernel in case a different kernel is used 
> > to load and restore a hibernation image containing it.
> 
> ok - so i guess i should drop this from x86.git:
> 
>  @@ -53,7 +53,6 @@ void __save_processor_state(struct saved
>          ctxt->cr2 = read_cr2();
>          ctxt->cr3 = read_cr3();
>          ctxt->cr4 = read_cr4();
>  -       ctxt->cr8 = read_cr8();
>   }
> 
> right?

Well, if cr8 is used for anything that matters, then yes.

> But i'm wondering - are we really ever resuming to a different  
> kernel version, for this to be an issue?

The boot kernel may be different from the kernel within the image, if that's
what you're asking for.

Rafael
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