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Date:   Wed, 09 Aug 2023 20:26:17 +0200
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Daniel Sneddon" <daniel.sneddon@linux.intel.com>,
        "Arnd Bergmann" <arnd@kernel.org>, x86@kernel.org,
        "Thomas Gleixner" <tglx@linutronix.de>,
        "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>,
        "Dave Hansen" <dave.hansen@linux.intel.com>,
        "Sean Christopherson" <seanjc@google.com>,
        "Paolo Bonzini" <pbonzini@redhat.com>,
        "Josh Poimboeuf" <jpoimboe@kernel.org>
Cc:     "H. Peter Anvin" <hpa@zytor.com>,
        "Peter Zijlstra" <peterz@infradead.org>,
        "Maxim Levitsky" <mlevitsk@redhat.com>,
        "Michal Luczaj" <mhal@rbox.co>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Subject: Re: [PATCH 2/2] x86: move gds_ucode_mitigated() declaration to header
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On Wed, Aug 9, 2023, at 18:54, Daniel Sneddon wrote:
> HI Arnd,
>
> On 8/9/23 06:05, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> The declaration got placed in the .c file of the caller, but that
>> causes a warning for the definition:
>> 
>> arch/x86/kernel/cpu/bugs.c:682:6: error: no previous prototype for 'gds_ucode_mitigated' [-Werror=missing-prototypes]
>
> When I build with gcc 9.4 and the x86_64_defconfig I don't see this warning even
> without this patch. I'm curious why you're seeing it and I'm not. Any ideas?

The warning is currently disabled by default, unless you build with
'make W=1'. I'm in the process of getting my last patches out to
change this so the warning is enabled by default though, so I was
phrasing this based on the future behavior. Sorry if this was confusing.

    Arnd