linux-kernel - [PATCH 4.14 215/293] perf/events/amd/uncore: Fix amd_uncore_llc ID to use pre-defined cpu_llc

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Message-Id: <20190729190840.965994077@linuxfoundation.org>
Date:   Mon, 29 Jul 2019 21:21:46 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        Borislav Petkov <bp@...e.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Janakarajan Natarajan <Janakarajan.Natarajan@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 215/293] perf/events/amd/uncore: Fix amd_uncore_llc ID to use pre-defined cpu_llc_id

[ Upstream commit 812af433038f984fd951224e8239b09188e36a13 ]

Current logic iterates over CPUID Fn8000001d leafs (Cache Properties)
to detect the last level cache, and derive the last-level cache ID.
However, this information is already available in the cpu_llc_id.
Therefore, make use of it instead.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>
Cc: Janakarajan Natarajan <Janakarajan.Natarajan@....com>
Link: http://lkml.kernel.org/r/1524864877-111962-3-git-send-email-suravee.suthikulpanit@amd.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/events/amd/uncore.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index 3a9ab16d9c2b..baa7e36073f9 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -19,6 +19,7 @@
 #include <asm/cpufeature.h>
 #include <asm/perf_event.h>
 #include <asm/msr.h>
+#include <asm/smp.h>
 
 #define NUM_COUNTERS_NB		4
 #define NUM_COUNTERS_L2		4
@@ -414,26 +415,8 @@ static int amd_uncore_cpu_starting(unsigned int cpu)
 	}
 
 	if (amd_uncore_llc) {
-		unsigned int apicid = cpu_data(cpu).apicid;
-		unsigned int nshared, subleaf, prev_eax = 0;
-
 		uncore = *per_cpu_ptr(amd_uncore_llc, cpu);
-		/*
-		 * Iterate over Cache Topology Definition leaves until no
-		 * more cache descriptions are available.
-		 */
-		for (subleaf = 0; subleaf < 5; subleaf++) {
-			cpuid_count(0x8000001d, subleaf, &eax, &ebx, &ecx, &edx);
-
-			/* EAX[0:4] gives type of cache */
-			if (!(eax & 0x1f))
-				break;
-
-			prev_eax = eax;
-		}
-		nshared = ((prev_eax >> 14) & 0xfff) + 1;
-
-		uncore->id = apicid - (apicid % nshared);
+		uncore->id = per_cpu(cpu_llc_id, cpu);
 
 		uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_llc);
 		*per_cpu_ptr(amd_uncore_llc, cpu) = uncore;
-- 
2.20.1