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Date:   Tue, 25 Jul 2023 14:15:16 +0200
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Borislav Petkov" <bp@alien8.de>, "Arnd Bergmann" <arnd@kernel.org>
Cc:     "Thomas Gleixner" <tglx@linutronix.de>,
        "Ingo Molnar" <mingo@redhat.com>,
        "Dave Hansen" <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        "Kees Cook" <keescook@chromium.org>,
        "Kim Phillips" <kim.phillips@amd.com>,
        "Alexey Kardashevskiy" <aik@amd.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: Fix amd_check_microcode() declaration
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On Tue, Jul 25, 2023, at 11:20, Borislav Petkov wrote:
> On Tue, Jul 25, 2023 at 10:26:13AM +0200, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> The newly added amd_check_microcode() function has two conflicting definitions
>> if CONFIG_CPU_SUP_AMD is enabled and CONFIG_MICROCODE_AMD is disabled. Since
>> the header with the stub definition is not included in cpu/amd.c, this only
>> causes a -Wmissing-prototype warning with W=1
>
> Can we please promote -Wmissing-prototype to default or is it too noisy
> yet?

I'm working on it, currently missing just 15 patches (down from 70 in 6.3)
before all randconfigs on x86 and arm are clean.

>> diff --git a/arch/x86/include/asm/microcode_amd.h b/arch/x86/include/asm/microcode_amd.h
>> index 9675c621c1ca4..6a860d40b0411 100644
>> --- a/arch/x86/include/asm/microcode_amd.h
>> +++ b/arch/x86/include/asm/microcode_amd.h

>> +#ifdef CONFIG_CPU_SUP_AMD
>> +extern void amd_check_microcode(void);
>> +#else
>>  static inline void amd_check_microcode(void) {}
>>  #endif
>> +
>>  #endif /* _ASM_X86_MICROCODE_AMD_H */
>
> Considering how cpu/amd.c provides the function implementation, that
> header gunk should not be in microcode_amd.h but in ...asm/processor.h,
> I'd say.

Ok, I'll send a v2 with that changed.

     Arnd