linux-kernel - Re: [tip:x86/cpu] x86/cpu: Create Zhaoxin processors architecture support file

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Date:   Sat, 22 Jun 2019 11:01:17 -0700
From:   Joe Perches <joe@...ches.com>
To:     HerryYang@...oxin.com, CooperYan@...oxin.com,
        linux-kernel@...r.kernel.org, hpa@...or.com, lenb@...nel.org,
        gregkh@...uxfoundation.org, QiyuanWang@...oxin.com,
        mingo@...nel.org, DavidWang@...oxin.com, tglx@...utronix.de,
        rjw@...ysocki.net, TonyWWang-oc@...oxin.com,
        linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/cpu] x86/cpu: Create Zhaoxin processors architecture
 support file

On Sat, 2019-06-22 at 03:16 -0700, tip-bot for Tony W Wang-oc wrote:
> Commit-ID:  761fdd5e3327db6c646a09bab5ad48cd42680cd2
> Gitweb:     https://git.kernel.org/tip/761fdd5e3327db6c646a09bab5ad48cd42680cd2
> Author:     Tony W Wang-oc <TonyWWang-oc@...oxin.com>
> AuthorDate: Tue, 18 Jun 2019 08:37:05 +0000
> Committer:  Thomas Gleixner <tglx@...utronix.de>
> CommitDate: Sat, 22 Jun 2019 11:45:57 +0200
> 
> x86/cpu: Create Zhaoxin processors architecture support file
> 
[]
> diff --git a/arch/x86/kernel/cpu/zhaoxin.c b/arch/x86/kernel/cpu/zhaoxin.c
[]
> +static void init_zhaoxin_cap(struct cpuinfo_x86 *c)
> +{
> +	u32  lo, hi;
> +
> +	/* Test for Extended Feature Flags presence */
> +	if (cpuid_eax(0xC0000000) >= 0xC0000001) {
> +		u32 tmp = cpuid_edx(0xC0000001);
> +
> +		/* Enable ACE unit, if present and disabled */
> +		if ((tmp & (ACE_PRESENT | ACE_ENABLED)) == ACE_PRESENT) {

trivia:

Perhaps this is more intelligible for humans to read
and it deduplicates the comment as:

		if ((tmp & ACE_PRESENT) && !(tmp & ACE_ENABLED))

The compiler produces the same object code.