linux-hardening - [PATCH 2/2] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

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Date: Thu, 2 May 2024 15:21:15 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: <tglx@...utronix.de>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>
CC: <peterz@...radead.org>, <mingo@...hat.com>, <ananth.narayan@....com>,
	<gautham.shenoy@....com>, <linux-perf-users@...r.kernel.org>,
	<linux-hardening@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<sandipan.das@....com>, <alexander.shishkin@...ux.intel.com>,
	<irogers@...gle.com>, <gustavoars@...nel.org>, <kprateek.nayak@....com>,
	<ravi.bangoria@....com>, Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Subject: [PATCH 2/2] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

After commit ("x86/cpu/topology: Add support for the AMD 0x80000026 leaf"),
on AMD processors that support extended CPUID leaf 0x80000026, the
topology_die_cpumask() and topology_logical_die_id() macros, no longer 
return the package cpumask and package id, instead they return the CCD 
(Core Complex Die) mask and id respectively. This leads to the energy-pkg 
event scope to be modified to CCD instead of package.

Replacing these macros with their package counterparts fixes the
energy-pkg event for AMD CPUs.

However due to the difference between the scope of energy-pkg event for 
Intel and AMD CPUs, we have to replace these macros conditionally only for
AMD CPUs.

On a 12 CCD 1 Package AMD Zen4 Genoa machine:

Before:
$ cat /sys/devices/power/cpumask
0,8,16,24,32,40,48,56,64,72,80,88.

The expected cpumask here is supposed to be just "0", as it is a package 
scope event, only one CPU will be collecting the event for all the CPUs in 
the package.

After:
$ cat /sys/devices/power/cpumask
0

Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Fixes: 63edbaa48a57 ("x86/cpu/topology: Add support for the AMD 0x80000026 leaf")
---
 arch/x86/events/rapl.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index 46e673585560..d77bf7959a43 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -102,6 +102,10 @@ static struct perf_pmu_events_attr event_attr_##v = {				\
 	.event_str	= str,							\
 };
 
+#define rapl_pmu_is_pkg_scope()				\
+	(boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||	\
+	 boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
+
 struct rapl_pmu {
 	raw_spinlock_t		lock;
 	int			n_active;
@@ -139,9 +143,21 @@ static unsigned int rapl_cntr_mask;
 static u64 rapl_timer_ms;
 static struct perf_msr *rapl_msrs;
 
+static inline unsigned int get_rapl_pmu_idx(int cpu)
+{
+	return rapl_pmu_is_pkg_scope() ? topology_logical_package_id(cpu) :
+					 topology_logical_die_id(cpu);
+}
+
+static inline cpumask_t *get_rapl_pmu_cpumask(int cpu)
+{
+	return rapl_pmu_is_pkg_scope() ? topology_core_cpumask(cpu) :
+					 topology_die_cpumask(cpu);
+}
+
 static inline struct rapl_pmu *cpu_to_rapl_pmu(unsigned int cpu)
 {
-	unsigned int rapl_pmu_idx = topology_logical_die_id(cpu);
+	unsigned int rapl_pmu_idx = get_rapl_pmu_idx(cpu);
 
 	/*
 	 * The unsigned check also catches the '-1' return value for non
@@ -542,6 +558,7 @@ static struct perf_msr amd_rapl_msrs[] = {
 
 static int rapl_cpu_offline(unsigned int cpu)
 {
+	cpumask_t *cpumask = get_rapl_pmu_cpumask(cpu);
 	struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
 	int target;
 
@@ -551,7 +568,7 @@ static int rapl_cpu_offline(unsigned int cpu)
 
 	pmu->cpu = -1;
 	/* Find a new cpu to collect rapl events */
-	target = cpumask_any_but(topology_die_cpumask(cpu), cpu);
+	target = cpumask_any_but(cpumask, cpu);
 
 	/* Migrate rapl events to the new target */
 	if (target < nr_cpu_ids) {
@@ -564,6 +581,8 @@ static int rapl_cpu_offline(unsigned int cpu)
 
 static int rapl_cpu_online(unsigned int cpu)
 {
+	unsigned int rapl_pmu_idx = get_rapl_pmu_idx(cpu);
+	cpumask_t *cpumask = get_rapl_pmu_cpumask(cpu);
 	struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
 	int target;
 
@@ -578,14 +597,14 @@ static int rapl_cpu_online(unsigned int cpu)
 		pmu->timer_interval = ms_to_ktime(rapl_timer_ms);
 		rapl_hrtimer_init(pmu);
 
-		rapl_pmus->pmus[topology_logical_die_id(cpu)] = pmu;
+		rapl_pmus->pmus[rapl_pmu_idx] = pmu;
 	}
 
 	/*
 	 * Check if there is an online cpu in the package which collects rapl
 	 * events already.
 	 */
-	target = cpumask_any_and(&rapl_cpu_mask, topology_die_cpumask(cpu));
+	target = cpumask_any_and(&rapl_cpu_mask, cpumask);
 	if (target < nr_cpu_ids)
 		return 0;
 
@@ -676,6 +695,9 @@ static int __init init_rapl_pmus(void)
 {
 	int nr_rapl_pmu = topology_max_packages() * topology_max_dies_per_package();
 
+	if (rapl_pmu_is_pkg_scope())
+		nr_rapl_pmu = topology_max_packages();
+
 	rapl_pmus = kzalloc(struct_size(rapl_pmus, pmus, nr_rapl_pmu), GFP_KERNEL);
 	if (!rapl_pmus)
 		return -ENOMEM;
-- 
2.34.1