linux-kernel - Re: [PATCH] efi: Clean up the efi_call_phys_[prolog|epilog]() save/restore interaction

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Message-ID: <20150310133637.GC17573@codeblueprint.co.uk>
Date:	Tue, 10 Mar 2015 13:36:37 +0000
From:	Matt Fleming <matt@...eblueprint.co.uk>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Tapasweni Pathak <tapaswenipathak@...il.com>,
	matt.fleming@...el.com, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, linux-efi@...r.kernel.org,
	linux-kernel@...r.kernel.org, Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH] efi: Clean up the efi_call_phys_[prolog|epilog]()
 save/restore interaction

On Tue, 03 Mar, at 07:48:50AM, Ingo Molnar wrote:
> 
> Also clean up the save_pgd global variable while at it.
> 
> untested as well.
> 
> Thanks,
> 
> 	Ingo
> 
> ==============>
> From 166625ceaef68fcbeee63adc63c02d75abcaf0db Mon Sep 17 00:00:00 2001
> From: Ingo Molnar <mingo@...nel.org>
> Date: Tue, 3 Mar 2015 07:42:48 +0100
> Subject: [PATCH] efi: Clean up the efi_call_phys_[prolog|epilog]() save/restore interaction
> 
> Currently x86-64 efi_call_phys_prolog() saves into a global variable (save_pgd),
> and efi_call_phys_epilog() restores the kernel pagetables from that global
> variable.
> 
> Change this to a cleaner save/restore pattern where the saving function returns
> the saved object and the restore function restores that.
> 
> Apply the same concept to the 32-bit code as well.
> 
> Plus this approach, as an added bonus, allows us to express the
> !efi_enabled(EFI_OLD_MEMMAP) situation in a clean fashion as well,
> via a 'NULL' return value.
> 
> Cc: Tapasweni Pathak <tapaswenipathak@...il.com>
> Signed-off-by: Ingo Molnar <mingo@...nel.org>
> ---
>  arch/x86/include/asm/efi.h     |  6 ++++--
>  arch/x86/platform/efi/efi.c    |  5 +++--
>  arch/x86/platform/efi/efi_32.c | 11 ++++++++---
>  arch/x86/platform/efi/efi_64.c | 26 ++++++++++++++++----------
>  4 files changed, 31 insertions(+), 17 deletions(-)

Applied, thanks!

-- 
Matt Fleming, Intel Open Source Technology Center
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