linux-kernel - Re: [PATCH v2 1/4] x86/mce: Add Zhaoxin MCE support

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Date:   Tue, 10 Sep 2019 13:51:16 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Tony W Wang-oc <TonyWWang-oc@...oxin.com>
Cc:     "tony.luck@...el.com" <tony.luck@...el.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "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>,
        "yazen.ghannam@....com" <yazen.ghannam@....com>,
        "vishal.l.verma@...el.com" <vishal.l.verma@...el.com>,
        "qiuxu.zhuo@...el.com" <qiuxu.zhuo@...el.com>,
        David Wang <DavidWang@...oxin.com>,
        "Cooper Yan(BJ-RD)" <CooperYan@...oxin.com>,
        "Qiyuan Wang(BJ-RD)" <QiyuanWang@...oxin.com>,
        "Herry Yang(BJ-RD)" <HerryYang@...oxin.com>
Subject: Re: [PATCH v2 1/4] x86/mce: Add Zhaoxin MCE support

On Tue, Sep 10, 2019 at 08:19:08AM +0000, Tony W Wang-oc wrote:
> All Zhaoxin newer CPUs support MCE that compatible with Intel's
> "Machine-Check Architecture", so add support for Zhaoxin MCE in
> mce/core.c.
> 
> Signed-off-by: Tony W Wang-oc <TonyWWang-oc@...oxin.com>
> ---
>  arch/x86/kernel/cpu/mce/core.c | 30 ++++++++++++++++++++++++------
>  1 file changed, 24 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
> index 743370e..3f878f6 100644
> --- a/arch/x86/kernel/cpu/mce/core.c
> +++ b/arch/x86/kernel/cpu/mce/core.c
> @@ -488,8 +488,9 @@ int mce_usable_address(struct mce *m)
>  	if (!(m->status & MCI_STATUS_ADDRV))
>  		return 0;
>  
> -	/* Checks after this one are Intel-specific: */
> -	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
> +	/* Checks after this one are Intel/Zhaoxin-specific: */
> +	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL &&
> +	    boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN)
>  		return 1;
>  
>  	if (!(m->status & MCI_STATUS_MISCV))
> @@ -510,7 +511,8 @@ bool mce_is_memory_error(struct mce *m)
>  	if (m->cpuvendor == X86_VENDOR_AMD ||
>  	    m->cpuvendor == X86_VENDOR_HYGON) {
>  		return amd_mce_is_memory_error(m);
> -	} else if (m->cpuvendor == X86_VENDOR_INTEL) {
> +	} else if (m->cpuvendor == X86_VENDOR_INTEL ||
> +		   m->cpuvendor == X86_VENDOR_ZHAOXIN) {
>  		/*
>  		 * Intel SDM Volume 3B - 15.9.2 Compound Error Codes
>  		 *

Make that a switch-case for better readability pls.

> @@ -1697,6 +1699,21 @@ static int __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
>  		if (c->x86 == 6 && c->x86_model == 45)
>  			quirk_no_way_out = quirk_sandybridge_ifu;
>  	}
> +
> +	if (c->x86_vendor == X86_VENDOR_ZHAOXIN) {
> +		/*
> +		 * All newer Zhaoxin CPUs support MCE broadcasting. Enable
> +		 * synchronization with a one second timeout.
> +		 */
> +		if ((c->x86 == 6 && c->x86_model == 0x19 &&
> +			(c->x86_stepping > 3 && c->x86_stepping < 8)) ||
> +		    (c->x86 == 6 && c->x86_model == 0x1f) ||
> +		     c->x86 > 6) {

Can this be simplified into maybe something like this:

	if (c->x86 > 6 || (c->x86_model == 0x19 || c->x86_model == 0x1f))

this is, of course, assuming that Zhaoxin doesn't do family < 6 and that
the other steppings for model 0x19 don't matter because they don't exist
or so...

-- 
Regards/Gruss,
    Boris.

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