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

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Message-ID: <540fd8d21fd043f6a8b49b018fc3b03e@zhaoxin.com>
Date:   Tue, 25 Jun 2019 08:15:01 +0000
From:   Tony W Wang-oc <TonyWWang-oc@...oxin.com>
To:     Thomas Gleixner <tglx@...utronix.de>
CC:     Joe Perches <joe@...ches.com>,
        "Herry Yang(BJ-RD)" <HerryYang@...oxin.com>,
        "Cooper Yan(BJ-RD)" <CooperYan@...oxin.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "hpa@...or.com" <hpa@...or.com>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "Qiyuan Wang(BJ-RD)" <QiyuanWang@...oxin.com>,
        "mingo@...nel.org" <mingo@...nel.org>,
        David Wang <DavidWang@...oxin.com>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>,
        "linux-tip-commits@...r.kernel.org" 
        <linux-tip-commits@...r.kernel.org>
Subject: 答复: 答复: [tip:x86/cpu] x86/cpu: Create Zhaoxin processors architecture support file

On Tue, 25 Jun 2019, Thomas Gleixner wrote:
> Tony,
> 
> On Tue, 25 Jun 2019, Tony W Wang-oc wrote:
> > On Sun, Jun 23, 2019, Joe Perches wrote:
> > > > 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.
> > >
> >
> > Thanks for the trivia, I will change this in the next version patch set.
> 
> as you might have noticed from the tip bot commit notification mail, your
> patch set has been merged into the tip tree and is queued for the 5.3 merge
> window. So a new patch set is pointless. If at all then you can send a
> delta patch.
> 
> Though I have to say, that I prefer the existing check:
> 
> > > > +		if ((tmp & (ACE_PRESENT | ACE_ENABLED)) == ACE_PRESENT) {
> 
> It's pretty clear, but that's really a matter of personal preference. So
> from my side there is nothing to do at all.

Got it, I will not change this code.

Thanks
TonyWWang-oc