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Commit daef1f35 authored by Zhao Yakui's avatar Zhao Yakui Committed by Len Brown
Browse files

ACPI: Check the returned value of set_cpus_allowed_ptr before T-state operation 



Now before it executes the T-state operation on one CPU, it will try to
migrate to the target CPU. Especially this is required on the system that
uses the MSR_IA32_THERMAL_CONTROL register to switch T-state.
But unfortunately it doesn't check whether the migration is successful or not.
In such case we will get/set the incorrect T-state on the offline CPU as
it fails in the migration to the offline CPU.

Signed-off-by: default avatarZhao Yakui <yakui.zhao@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 3c0eee3f

drivers/acpi/processor_throttling.c

+21 −3
Original line number Diff line number Diff line
@@ -876,7 +876,11 @@ static int acpi_processor_get_throttling(struct acpi_processor *pr) 
	 */

	cpumask_copy(saved_mask, &current->cpus_allowed);

	/* FIXME: use work_on_cpu() */

	set_cpus_allowed_ptr(current, cpumask_of(pr->id));

	if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) {

		/* Can't migrate to the target pr->id CPU. Exit */

		free_cpumask_var(saved_mask);

		return -ENODEV;

	}

	ret = pr->throttling.acpi_processor_get_throttling(pr);

	/* restore the previous state */

	set_cpus_allowed_ptr(current, saved_mask);
@@ -1051,6 +1055,14 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
		return -ENOMEM;

	}



	if (cpu_is_offline(pr->id)) {

		/*

		 * the cpu pointed by pr->id is offline. Unnecessary to change

		 * the throttling state any more.

		 */

		return -ENODEV;

	}



	cpumask_copy(saved_mask, &current->cpus_allowed);

	t_state.target_state = state;

	p_throttling = &(pr->throttling);
@@ -1074,7 +1086,11 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
	 */

	if (p_throttling->shared_type == DOMAIN_COORD_TYPE_SW_ANY) {

		/* FIXME: use work_on_cpu() */

		set_cpus_allowed_ptr(current, cpumask_of(pr->id));

		if (set_cpus_allowed_ptr(current, cpumask_of(pr->id))) {

			/* Can't migrate to the pr->id CPU. Exit */

			ret = -ENODEV;

			goto exit;

		}

		ret = p_throttling->acpi_processor_set_throttling(pr,

						t_state.target_state, force);

	} else {
@@ -1106,7 +1122,8 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
			}

			t_state.cpu = i;

			/* FIXME: use work_on_cpu() */

			set_cpus_allowed_ptr(current, cpumask_of(i));

			if (set_cpus_allowed_ptr(current, cpumask_of(i)))

				continue;

			ret = match_pr->throttling.

				acpi_processor_set_throttling(

				match_pr, t_state.target_state, force);
@@ -1126,6 +1143,7 @@ int acpi_processor_set_throttling(struct acpi_processor *pr, 
	/* restore the previous state */

	/* FIXME: use work_on_cpu() */

	set_cpus_allowed_ptr(current, saved_mask);

exit:

	free_cpumask_var(online_throttling_cpus);

	free_cpumask_var(saved_mask);

	return ret;