linux-kernel - [PATCH v2 3/3] cpufreq: amd-pstate: Add a module device table

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

Message-ID: <20220329015947.565-4-mario.limonciello@amd.com>
Date:   Mon, 28 Mar 2022 20:59:47 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     Huang Rui <ray.huang@....com>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
CC:     "open list:AMD PSTATE DRIVER" <linux-pm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH v2 3/3] cpufreq: amd-pstate: Add a module device table

`amd-pstate` currently only loads automatically if compiled into the
kernel.  To improve the usability, add a module device table that
will load when AMD CPUs that support CPPC are detected.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
v1->v2:
 * Add comment to indicate need of SBIOS support.

 drivers/cpufreq/amd-pstate.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 7dc2e344f222..9f78849654e7 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -705,6 +705,17 @@ static void __exit amd_pstate_exit(void)
 	amd_pstate_enable(false);
 }
 
+/*
+ * This will only match the HW feature, there still needs to be appropriate
+ * SBIOS support, so it's possible that in such cases this causes a module
+ * load with -ENODEV as the result.
+ */
+static const struct x86_cpu_id __maybe_unused amd_pstate_ids[] = {
+	X86_MATCH_VENDOR_FEATURE(AMD, X86_FEATURE_CPPC, NULL),
+	{}
+};
+MODULE_DEVICE_TABLE(x86cpu, amd_pstate_ids);
+
 module_init(amd_pstate_init);
 module_exit(amd_pstate_exit);
 
-- 
2.34.1