linux-kernel - [PATCH v3] turbostat: Read extended processor family from CPUID

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Message-Id: <20180727115053.8965-1-calvin.walton@kepstin.ca>
Date:   Fri, 27 Jul 2018 07:50:53 -0400
From:   Calvin Walton <calvin.walton@...stin.ca>
To:     Len Brown <lenb@...nel.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Calvin Walton <calvin.walton@...stin.ca>
Subject: [PATCH v3] turbostat: Read extended processor family from CPUID

This fixes the reported family on modern AMD processors (e.g. Ryzen,
which is family 0x17). Previously these processors all showed up as
family 0xf.

See the document
https://support.amd.com/TechDocs/56255_OSRR.pdf
section CPUID_Fn00000001_EAX for how to calculate the family
from the BaseFamily and ExtFamily values.

This matches the code in arch/x86/lib/cpu.c

Signed-off-by: Calvin Walton <calvin.walton@...stin.ca>
---

v3: Having just looked at the arch/x86/lib/cpu.c code again, I realized
that it *didn't* actually match - the kernel code uses family >= 6 for
applying the extended model number, while I was applying it only to
 family == 6 or family >= 0xf. Change that to match for consistency.

v2: I'm still working on updating the RAPL patch on top of the changes for
v4.18, but this CPUID fix doesn't have to wait.

 tools/power/x86/turbostat/turbostat.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index bd9c6b31a504..ed024deed36f 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -4031,7 +4031,9 @@ void process_cpuid()
 	family = (fms >> 8) & 0xf;
 	model = (fms >> 4) & 0xf;
 	stepping = fms & 0xf;
-	if (family == 6 || family == 0xf)
+	if (family == 0xf)
+		family += (fms >> 20) & 0xff;
+	if (family >= 6)
 		model += ((fms >> 16) & 0xf) << 4;

 	if (!quiet) {
-- 
2.18.0