Re: [PATCH 02/14] x86-64/efi: Use EFI to deal with platform wallclock (again)
From: Matt Fleming
Date: Thu Dec 19 2013 - 05:49:37 EST
On Thu, 19 Dec, at 06:20:16PM, Lee, Chun-Yi wrote:
> From: Jan Beulich <JBeulich@xxxxxxxx>
>
> Other than ix86, x86-64 on EFI so far didn't set the
> {g,s}et_wallclock accessors to the EFI routines, thus
> incorrectly using raw RTC accesses instead.
>
> Simply removing the #ifdef around the respective code isn't
> enough, however: While so far early get-time calls were done in
> physical mode, this doesn't work properly for x86-64, as virtual
> addresses would still need to be set up for all runtime regions
> (which wasn't the case on the system I have access to), so
> instead the patch moves the call to efi_enter_virtual_mode()
> ahead (which in turn allows to drop all code related to calling
> efi-get-time in physical mode).
>
> Additionally the earlier calling of efi_set_executable()
> requires the CPA code to cope, i.e. during early boot it must be
> avoided to call cpa_flush_array(), as the first thing this
> function does is a BUG_ON(irqs_disabled()).
>
> Also make the two EFI functions in question here static -
> they're not being referenced elsewhere.
>
> History:
>
> This commit was originally merged as bacef661acdb ("x86-64/efi:
> Use EFI to deal with platform wall clock") but it resulted in some
> ASUS machines no longer booting due to a firmware bug, and so was
> reverted in f026cfa82f62.
>
> Then a pre-emptive fix for the buggy ASUS firmware was merged in
> 03a1c254975e ("x86, efi: 1:1 pagetable mapping for virtual EFI
> calls") but it causes odd bootup problems on x86-64. So this patch
> revoked again by 11520e5e7c1.
>
> Now Borislav Petkov's "EFI runtime services virtual mapping" is
> merged to EFI 'next' branch. So this patch can be reapplied again.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> Tested-by: Matt Fleming <matt.fleming@xxxxxxxxx>
> Acked-by: Matthew Garrett <mjg@xxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx> [added commit history]
> Acked-by: Lee, Chun-Yi <jlee@xxxxxxxx>
> ---
> arch/x86/mm/pageattr.c | 10 ++++++----
> arch/x86/platform/efi/efi.c | 35 +++++++++++------------------------
> include/linux/efi.h | 2 --
> init/main.c | 8 ++++----
> 4 files changed, 21 insertions(+), 34 deletions(-)
Lee, you can't just simply resend this patch with all the tags - I
haven't tested this version with any recent changes and I'm pretty sure
Matthew isn't going to Ack it.
Do you know if anyone has tested this patch with Borislav's recent
changes?
--
Matt Fleming, Intel Open Source Technology Center
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