linux-kernel - [PATCH] x86/cpu/amd: Set __max_die_per

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Date:   Mon, 11 Jan 2021 11:14:55 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Johnathan Smithinovic <johnathan.smithinovic@....at>,
        Rafael Kitover <rkitover@...il.com>
Subject: [PATCH] x86/cpu/amd: Set __max_die_per_package on AMD

From: Yazen Ghannam <Yazen.Ghannam@....com>

Set the maximum DIE per package variable on AMD using the
NodesPerProcessor topology value. This will be used by RAPL, among
others, to determine the maximum number of DIEs on the system in order
to do per-DIE manipulations.

 [ bp: Productize into a proper patch. ]

Fixes: 028c221ed190 ("x86/CPU/AMD: Save AMD NodeId as cpu_die_id")
Reported-by: Johnathan Smithinovic <johnathan.smithinovic@....at>
Reported-by: Rafael Kitover <rkitover@...il.com>
Signed-off-by: Yazen Ghannam <Yazen.Ghannam@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Tested-by: Johnathan Smithinovic <johnathan.smithinovic@....at>
Tested-by: Rafael Kitover <rkitover@...il.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=210939
---
 arch/x86/kernel/cpu/amd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index f8ca66f3d861..347a956f71ca 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -542,12 +542,12 @@ static void bsp_init_amd(struct cpuinfo_x86 *c)
 		u32 ecx;
 
 		ecx = cpuid_ecx(0x8000001e);
-		nodes_per_socket = ((ecx >> 8) & 7) + 1;
+		__max_die_per_package = nodes_per_socket = ((ecx >> 8) & 7) + 1;
 	} else if (boot_cpu_has(X86_FEATURE_NODEID_MSR)) {
 		u64 value;
 
 		rdmsrl(MSR_FAM10H_NODE_ID, value);
-		nodes_per_socket = ((value >> 3) & 7) + 1;
+		__max_die_per_package = nodes_per_socket = ((value >> 3) & 7) + 1;
 	}
 
 	if (!boot_cpu_has(X86_FEATURE_AMD_SSBD) &&
-- 
2.29.2