cpufreq: powernv: Fix unsafe notifiers (966c08de) · Commits · 戴 / test

The PowerNV cpufreq driver registers two notifiers: one to catch throttle messages from the OCC and one to bump the CPU frequency back to normal before a reboot. Both require the cpufreq driver to be registered in order to function since the notifier callbacks use various cpufreq_*() functions. Right now we register both notifiers before we've initialised the driver. This seems to work, but we should head off any protential problems by registering the notifiers after the driver is initialised. Signed-off-by:

Oliver O'Halloran <oohall@gmail.com> Reviewed-by:

Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200206062622.28235-2-oohall@gmail.com

drivers/cpufreq/powernv-cpufreq.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -1114,9 +1114,6 @@ static int __init powernv_cpufreq_init(void)
		if (rc)
		goto out;

		register_reboot_notifier(&powernv_cpufreq_reboot_nb);
		opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);

		if (powernv_pstate_info.wof_enabled)
		powernv_cpufreq_driver.boost_enabled = true;
		else
		@@ -1125,15 +1122,17 @@ static int __init powernv_cpufreq_init(void)
		rc = cpufreq_register_driver(&powernv_cpufreq_driver);
		if (rc) {
		pr_info("Failed to register the cpufreq driver (%d)\n", rc);
		goto cleanup_notifiers;
		goto cleanup;
		}

		if (powernv_pstate_info.wof_enabled)
		cpufreq_enable_boost_support();

		register_reboot_notifier(&powernv_cpufreq_reboot_nb);
		opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);

		return 0;
		cleanup_notifiers:
		unregister_all_notifiers();
		cleanup:
		clean_chip_info();
		out:
		pr_info("Platform driver disabled. System does not support PState control\n");

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