linux-kernel - [PATCH v2] platform/x86/intel-uncore-freq: Do not present separate package-die domain

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240820204558.1296319-1-srinivas.pandruvada@linux.intel.com>
Date: Tue, 20 Aug 2024 13:45:58 -0700
From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To: hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com
Cc: platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: [PATCH v2] platform/x86/intel-uncore-freq: Do not present separate package-die domain

The scope of uncore control is per power domain with TPMI.

There are two types of processor topologies can be presented by CPUID
extended topology leaf irrespective of the hardware architecture:

1. A die is not enumerated in CPUID. In this case there is only one die
in a package is visible. In this case there can be multiple power domains
in a single die.
2. A power domain in a package is enumerated as a die in CPUID. So
there is one power domain per die.

To allow die level controls, the current implementation creates a root
domain and aggregates all information from power domains in it. This
is well suited for configuration 1 above.

But for configuration 2 above, the root domain will present the same
information as present by power domain. So, no use of aggregating. To
check the configuration, call topology_max_dies_per_package(). If it is
more than one, avoid creating root domain.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
---
This is a forward looking change as TPMI is architectural and should
support all topologies.

v2
Updated commit description as suggested.

 .../x86/intel/uncore-frequency/uncore-frequency-tpmi.c     | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
index 2016acf44f6a..e6047fbbea76 100644
--- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
+++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
@@ -557,6 +557,9 @@ static int uncore_probe(struct auxiliary_device *auxdev, const struct auxiliary_

 	auxiliary_set_drvdata(auxdev, tpmi_uncore);

+	if (topology_max_dies_per_package() > 1)
+		return 0;
+
 	tpmi_uncore->root_cluster.root_domain = true;
 	tpmi_uncore->root_cluster.uncore_root = tpmi_uncore;

@@ -580,7 +583,9 @@ static void uncore_remove(struct auxiliary_device *auxdev)
 {
 	struct tpmi_uncore_struct *tpmi_uncore = auxiliary_get_drvdata(auxdev);

-	uncore_freq_remove_die_entry(&tpmi_uncore->root_cluster.uncore_data);
+	if (tpmi_uncore->root_cluster.root_domain)
+		uncore_freq_remove_die_entry(&tpmi_uncore->root_cluster.uncore_data);
+
 	remove_cluster_entries(tpmi_uncore);

 	uncore_freq_common_exit();
-- 
2.45.0