linux-kernel - Re: [PATCH v9 08/26] x86/fpu/xstate: Introduce helpers to manage the XSTATE buffer dynamically

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Date:   Mon, 16 Aug 2021 20:53:21 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Bae, Chang Seok" <chang.seok.bae@...el.com>
Cc:     "Lutomirski, Andy" <luto@...nel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...nel.org" <mingo@...nel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "Brown, Len" <len.brown@...el.com>,
        "Hansen, Dave" <dave.hansen@...el.com>,
        "Macieira, Thiago" <thiago.macieira@...el.com>,
        "Liu, Jing2" <jing2.liu@...el.com>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v9 08/26] x86/fpu/xstate: Introduce helpers to manage the
 XSTATE buffer dynamically

On Mon, Aug 16, 2021 at 06:33:37PM +0000, Bae, Chang Seok wrote:
> Without DISABLE_XSAVES or something under ifdef CONFIG_X86_XX in
> $arch/x86/include/asm/disable-features.h, I don’t see the difference with this
> macro. Am I missing anything here? Or, boot_cpu_has() is going to be
> deprecated everywhere?

There's:

cpu_has
this_cpu_has
cpu_feature_enabled
boot_cpu_has
static_cpu_has

All code where it doesn't matter which CPU, should use
cpu_feature_enabled() and simplicity will ensue in these here lands.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette