linux-kernel - Re: [PATCH v3 1/1] x86/cpu: Make sure flag_is_changeable

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Message-ID: <52362D81-CE7E-4F06-AA1E-B8C55933B4B4@zytor.com>
Date: Fri, 08 Nov 2024 12:50:49 +0100
From: "H. Peter Anvin" <hpa@...or.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev
CC: Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Bill Wendling <morbo@...gle.com>,
        Justin Stitt <justinstitt@...gle.com>,
        Dave Hansen <dave.hansen@...el.com>
Subject: Re: [PATCH v3 1/1] x86/cpu: Make sure flag_is_changeable_p() is always being used

On November 8, 2024 10:29:02 AM GMT+01:00, Andy Shevchenko <andriy.shevchenko@...ux.intel.com> wrote:
>On Tue, Sep 10, 2024 at 11:42:42AM +0300, Andy Shevchenko wrote:
>> When flag_is_changeable_p() is unused, it prevents kernel builds
>> with clang, `make W=1` and CONFIG_WERROR=y:
>> 
>> arch/x86/kernel/cpu/common.c:351:19: error: unused function 'flag_is_changeable_p' [-Werror,-Wunused-function]
>>   351 | static inline int flag_is_changeable_p(u32 flag)
>>       |                   ^~~~~~~~~~~~~~~~~~~~
>> 
>> Fix this by moving core around to make sure flag_is_changeable_p() is
>> always being used.
>> 
>> See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
>> inline functions for W=1 build").
>
>Any comments on this? Can it be applied?
>

Incidentally, this really should be "unsigned long" rather than u32, although I believe it is only used on 32 bits.