linux-kernel - Re: [PATCH v2 7/7] x86/CPU/AMD: Output the AGESA version to the logs

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Message-ID: <20251218154708.GC1346661@yaz-khff2.amd.com>
Date: Thu, 18 Dec 2025 10:47:08 -0500
From: Yazen Ghannam <yazen.ghannam@....com>
To: Mario Limonciello <superm1@...nel.org>
Cc: "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
	Jean Delvare <jdelvare@...e.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H . Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 7/7] x86/CPU/AMD: Output the AGESA version to the logs

On Wed, Dec 17, 2025 at 03:21:17PM -0600, Mario Limonciello wrote:
> On 12/17/25 3:18 PM, Yazen Ghannam wrote:
> > On Tue, Dec 16, 2025 at 06:33:54AM -0600, Mario Limonciello (AMD) wrote:
> > > On AMD Zen platforms that are running AGESA, there is sometimes
> > > DMI additional string for the AGESA version that can be helpful when
> > > debugging an issue.  If this string is found output to kernel logs.
> > > 
> > > Signed-off-by: Mario Limonciello (AMD) <superm1@...nel.org>
> > > ---
> > >   arch/x86/kernel/cpu/amd.c | 18 ++++++++++++++++++
> > >   1 file changed, 18 insertions(+)
> > > 
> > > diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> > > index c19c4ee74dd1f..8f44439d3f993 100644
> > > --- a/arch/x86/kernel/cpu/amd.c
> > > +++ b/arch/x86/kernel/cpu/amd.c
> > > @@ -1,6 +1,7 @@
> > >   // SPDX-License-Identifier: GPL-2.0-only
> > >   #define pr_fmt(fmt) "x86/amd: " fmt
> > > +#include <linux/dmi.h>
> > >   #include <linux/export.h>
> > >   #include <linux/bitops.h>
> > >   #include <linux/elf.h>
> > > @@ -1406,3 +1407,20 @@ static __init int print_s5_reset_status_mmio(void)
> > >   	return 0;
> > >   }
> > >   late_initcall(print_s5_reset_status_mmio);
> > > +
> > > +#ifdef CONFIG_DMI
> > > +static __init int print_agesa_dmi_info(void)
> > > +{
> > > +	const struct dmi_device *dev = NULL;
> > > +
> > > +	while ((dev = dmi_find_device(DMI_DEV_TYPE_ADDITIONAL, NULL, dev))) {
> > > +		if (!strncmp(dev->name, "AGESA", 5)) {
> > > +			pr_info("%s\n", dev->name);
> > > +			break;
> > > +		}
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +late_initcall(print_agesa_dmi_info);
> > > +#endif
> > > 
> > 
> > The Zen check is gone. Is that intentional?
> > 
> 
> No it's not, it's a good catch.  We don't have an AGESA version in SMBIOS
> data on pre-zen hardware.
> 
> I'll add in a check like we do for print_s5_reset_status_mmio() for the next
> spin.
> 
>         if (!cpu_feature_enabled(X86_FEATURE_ZEN))
>                 return 0;
> 

In that case, please consider a wrapper function that checks for Zen and
calls the two functions: AGESA and S5_RESET_STATUS.

Thanks,
Yazen