linux-kernel - [PATCH v1] cpufreq: intel_pstate: Relocate platform preference check

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>] [day] [month] [year] [list]

Message-ID: <2776745.mvXUDI8C0e@rjwysocki.net>
Date: Fri, 07 Feb 2025 13:48:40 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Zhang Rui <rui.zhang@...el.com>
Subject: [PATCH v1] cpufreq: intel_pstate: Relocate platform preference check

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Move the invocation of intel_pstate_platform_pwr_mgmt_exists() before
checking whether or not HWP is enabled because it does not depend on
any code running before it except for the vendor check and if CPU
performance scaling is going to be carried out by the platform, all of
the code that runs before that function (again, except for the vendor
check) is redundant.

This is not expected to alter any functionality except for the ordering
of messages printed by intel_pstate_init() when it is going to return an
error before attempting to register the driver.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpufreq/intel_pstate.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -3688,6 +3688,15 @@
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 		return -ENODEV;

+	/*
+	 * The Intel pstate driver will be ignored if the platform
+	 * firmware has its own power management modes.
+	 */
+	if (intel_pstate_platform_pwr_mgmt_exists()) {
+		pr_info("P-states controlled by the platform\n");
+		return -ENODEV;
+	}
+
 	id = x86_match_cpu(hwp_support_ids);
 	if (id) {
 		hwp_forced = intel_pstate_hwp_is_enabled();
@@ -3743,15 +3752,6 @@
 		default_driver = &intel_cpufreq;

 hwp_cpu_matched:
-	/*
-	 * The Intel pstate driver will be ignored if the platform
-	 * firmware has its own power management modes.
-	 */
-	if (intel_pstate_platform_pwr_mgmt_exists()) {
-		pr_info("P-states controlled by the platform\n");
-		return -ENODEV;
-	}
-
 	if (!hwp_active && hwp_only)
 		return -ENOTSUPP;