linux-kernel - Re: [Part1 PATCH v6 02/17] x86/mm: Add Secure Encrypted Virtualization (SEV) support

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Message-ID: <20171016181835.a65fogoxdrl2j36z@pd.tnic>
Date:   Mon, 16 Oct 2017 20:18:35 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Brijesh Singh <brijesh.singh@....com>
Cc:     x86@...nel.org, Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [Part1 PATCH v6 02/17] x86/mm: Add Secure Encrypted
 Virtualization (SEV) support

On Mon, Oct 16, 2017 at 12:46:20PM -0500, Brijesh Singh wrote:
> sev_enabled lives in .data section and looking at the objdump it seems
> to initialized to zero. So, I think its safe to remove the initialization.

So I'd assume that static means it gets cleared to 0 automatically, even
if it is not in the .bss section. And Tom put it in the .data section to
protect it from the .bss clearing later.

To quote the C99 standard:

"If an object that has static storage duration is not initialized
explicitly, then:

...

— if it has arithmetic type, it is initialized to (positive or unsigned) zero;"

-- 
Regards/Gruss,
    Boris.

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