linux-kernel - Re: [PATCH] x86-64: use EFI to deal with platform wall clock

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Message-ID: <20120515124707.GB25248@srcf.ucam.org>
Date:	Tue, 15 May 2012 13:47:07 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	Jan Beulich <JBeulich@...e.com>
Cc:	mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
	matt.fleming@...ux.intel.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86-64: use EFI to deal with platform wall clock

On Tue, May 15, 2012 at 01:18:19PM +0100, Jan Beulich wrote:

> Simply removing the #ifdef around the respective code isn't enough,
> however: The runtime code must not only be forced to be executable, it
> also must have a proper virtual address set (which on at least the
> system I'm testing on isn't the case for all necessary regions, or at
> least not as early as they're now being required).

I don't understand this. The get_time pointer won't be updated to the 
virtual function until the end of efi_enter_virtual_mode, at which point 
all runtime regions should have a virtual address mapped. We also call 
runtime_code_page_mkexec() immediately after updating that pointer, 
although maybe the order should be swapped. So I think the bug you're 
fixing is not the bug you think you're fixing...

-- 
Matthew Garrett | mjg59@...f.ucam.org
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