linux-kernel - RE: [PATCH v2 06/10] x86/mce: Convert multiple if () statements into a switch() statement

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Message-ID: <SJ1PR11MB6083AB84528B99F6FC0C3A6AFC4E2@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Thu, 24 Oct 2024 21:41:17 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: "Mehta, Sohil" <sohil.mehta@...el.com>, "Zhuo, Qiuxu"
	<qiuxu.zhuo@...el.com>, "Hansen, Dave" <dave.hansen@...el.com>
CC: "bp@...en8.de" <bp@...en8.de>, "tglx@...utronix.de" <tglx@...utronix.de>,
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
	"mingo@...hat.com" <mingo@...hat.com>, "hpa@...or.com" <hpa@...or.com>,
	"x86@...nel.org" <x86@...nel.org>, "linux-edac@...r.kernel.org"
	<linux-edac@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 06/10] x86/mce: Convert multiple if () statements into
 a switch() statement

> > -       if (c->x86 == 6 && c->x86_model < 0x1A && this_cpu_read(mce_num_banks) > 0)
> > +       if (c->x86_vfm < INTEL_NEHALEM_EP && this_cpu_read(mce_num_banks) > 0)
> >                 mce_banks[0].init = false;
> >
> > Updated code now matches for families before 6 (486, Pentium). 486 would never get
> > to this code. But I think from the comments about machine check bank 0 being magic
> > that Pentium had some rudimentary support.
> >
>
> As you mentioned it yourself (the last time I was concerned about family
> 5), the following check should cover this scenario?
>
> > @@ -1924,6 +1924,10 @@ static void apply_quirks_intel(struct cpuinfo_x86 *c)
> >         struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array);
> >         struct mca_config *cfg = &mca_cfg;
> >
> > +       /* Older CPUs (prior to family 6) don't need quirks. */
> > +       if (c->x86_vfm < INTEL_PENTIUM_PRO)
> > +               return;

So I did. I was right about it too.

Sorry for the noise. This patch looks good.

-Tony