Commit 43ff36c4 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

Revert "ACPI: processor: idle: Optimize ACPI idle driver registration" 



Revert commit 7a8c994c ("ACPI: processor: idle: Optimize ACPI idle
driver registration") because it is reported to introduce a cpuidle
regression leading to a kernel crash on a platform using the ACPI idle
driver.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: default avatarBorislav Petkov <bp@alien8.de>
Tested-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Closes: https://lore.kernel.org/lkml/20251124200019.GIaSS5U9HhsWBotrQZ@fat_crate.local/
parent 1a8b3501

drivers/acpi/processor_driver.c

+0 −3
Original line number Diff line number Diff line
@@ -263,8 +263,6 @@ static int __init acpi_processor_driver_init(void) 
	if (result < 0)

		return result;



	acpi_processor_register_idle_driver();



	result = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,

				   "acpi/cpu-drv:online",

				   acpi_soft_cpu_online, NULL);
@@ -303,7 +301,6 @@ static void __exit acpi_processor_driver_exit(void) 


	cpuhp_remove_state_nocalls(hp_online);

	cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);

	acpi_processor_unregister_idle_driver();

	driver_unregister(&acpi_processor_driver);

}

drivers/acpi/processor_idle.c

+23 −42
Original line number Diff line number Diff line
@@ -1357,48 +1357,7 @@ int acpi_processor_power_state_has_changed(struct acpi_processor *pr) 
	return 0;

}



void acpi_processor_register_idle_driver(void)

{

	struct acpi_processor *pr;

	int ret = -ENODEV;

	int cpu;



	/*

	 * Acpi idle driver is used by all possible CPUs.

	 * Install the idle handler by the processor power info of one in them.

	 * Note that we use previously set idle handler will be used on

	 * platforms that only support C1.

	 */

	for_each_cpu(cpu, (struct cpumask *)cpu_possible_mask) {

		pr = per_cpu(processors, cpu);

		if (!pr)

			continue;



		ret = acpi_processor_get_power_info(pr);

		if (!ret) {

			pr->flags.power_setup_done = 1;

			acpi_processor_setup_cpuidle_states(pr);

			break;

		}

	}



	if (ret) {

		pr_debug("No ACPI power information from any CPUs.\n");

		return;

	}



	ret = cpuidle_register_driver(&acpi_idle_driver);

	if (ret) {

		pr_debug("register %s failed.\n", acpi_idle_driver.name);

		return;

	}

	pr_debug("%s registered with cpuidle.\n", acpi_idle_driver.name);

}



void acpi_processor_unregister_idle_driver(void)

{

	cpuidle_unregister_driver(&acpi_idle_driver);

}

static int acpi_processor_registered;



int acpi_processor_power_init(struct acpi_processor *pr)

{
@@ -1413,7 +1372,22 @@ int acpi_processor_power_init(struct acpi_processor *pr) 
	if (!acpi_processor_get_power_info(pr))

		pr->flags.power_setup_done = 1;



	/*

	 * Install the idle handler if processor power management is supported.

	 * Note that we use previously set idle handler will be used on

	 * platforms that only support C1.

	 */

	if (pr->flags.power) {

		/* Register acpi_idle_driver if not already registered */

		if (!acpi_processor_registered) {

			acpi_processor_setup_cpuidle_states(pr);

			retval = cpuidle_register_driver(&acpi_idle_driver);

			if (retval)

				return retval;

			pr_debug("%s registered with cpuidle\n",

				 acpi_idle_driver.name);

		}



		dev = kzalloc(sizeof(*dev), GFP_KERNEL);

		if (!dev)

			return -ENOMEM;
@@ -1426,11 +1400,14 @@ int acpi_processor_power_init(struct acpi_processor *pr) 
		 */

		retval = cpuidle_register_device(dev);

		if (retval) {

			if (acpi_processor_registered == 0)

				cpuidle_unregister_driver(&acpi_idle_driver);



			per_cpu(acpi_cpuidle_device, pr->id) = NULL;

			kfree(dev);

			return retval;

		}

		acpi_processor_registered++;

	}

	return 0;

}
@@ -1444,6 +1421,10 @@ int acpi_processor_power_exit(struct acpi_processor *pr) 


	if (pr->flags.power) {

		cpuidle_unregister_device(dev);

		acpi_processor_registered--;

		if (acpi_processor_registered == 0)

			cpuidle_unregister_driver(&acpi_idle_driver);



		kfree(dev);

	}

include/acpi/processor.h

+0 −2
Original line number Diff line number Diff line
@@ -423,8 +423,6 @@ int acpi_processor_power_init(struct acpi_processor *pr); 
int acpi_processor_power_exit(struct acpi_processor *pr);

int acpi_processor_power_state_has_changed(struct acpi_processor *pr);

int acpi_processor_hotplug(struct acpi_processor *pr);

void acpi_processor_register_idle_driver(void);

void acpi_processor_unregister_idle_driver(void);

#else

static inline int acpi_processor_power_init(struct acpi_processor *pr)

{