Date: Thu, 11 Jun 2015 14:14:39 +0100
From: Matt Fleming <matt@codeblueprint.co.uk>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Michal Marek <mmarek@suse.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andi Kleen <andi@firstfloor.org>, x86@kernel.org,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
        Matt Fleming <matt.fleming@intel.com>, linux-efi@vger.kernel.org
Subject: Re: [PATCH v5 06/10] x86/asm/efi: Fix asmvalidate warnings for
 efi_stub_64.S
Message-ID: <20150611131438.GB19243@codeblueprint.co.uk>
References: <cover.1433937132.git.jpoimboe@redhat.com>
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On Wed, 10 Jun, at 07:06:14AM, Josh Poimboeuf wrote:
> Fix the following asmvalidate warnings:
> 
>    asmvalidate: arch/x86/platform/efi/efi_stub_64.o: efi_call(): missing FP_SAVE/RESTORE macros
>    asmvalidate: arch/x86/boot/compressed/efi_stub_64.o: efi_call(): missing FP_SAVE/RESTORE macros
> 
> efi_call() is a non-leaf callable function, so save/restore the frame
> pointer with FP_SAVE/RESTORE.
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Matt Fleming <matt.fleming@intel.com>
> Cc: linux-efi@vger.kernel.org
> ---
>  arch/x86/platform/efi/efi_stub_64.S | 3 +++
>  1 file changed, 3 insertions(+)

Yeah, fair enough. Though it's worth noting that because we're calling
firmware functions, which use the Microsoft ABI, %rbp will be saved by
the callee function if used. Anyway,

Acked-by: Matt Fleming <matt.fleming@intel.com>

And since I know Boris in particular has poked around in this area, an
ACK from him would be worth alot.

-- 
Matt Fleming, Intel Open Source Technology Center
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