Merge tag 'pm+acpi-4.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI fixes from Rafael Wysocki:
 "These fix three regressions, two recent ones (cpufreq core and ACPI
  device power management) and one introduced during the 4.1 cycle
  (intel_pstate).

  Specifics:

   - Fix a recently introduced issue in the cpufreq core causing it to
     attempt to create duplicate symbolic links to the policy directory
     in sysfs for CPUs that are offline when the cpufreq driver is being
     registered (Rafael J Wysocki)

   - Fix a recently introduced problem in the ACPI device power
     management core code causing it to store an incorrect value in the
     device object's power.state field in some cases which in turn leads
     to attempts to turn power resources off while they should still be
     on going forward (Mika Westerberg)

   - Fix an intel_pstate driver issue introduced during the 4.1 cycle
     which leads to kernel panics on boot on Knights Landing chips due
     to incomplete support for them in that driver (Lukasz Anaczkowski)"

* tag 'pm+acpi-4.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: Avoid attempts to create duplicate symbolic links
  ACPI / PM: Use target_state to set the device power state
  intel_pstate: Add get_scaling cpu_defaults param to Knights Landing

drivers/acpi/device_pm.c

@@ -231,7 +231,7 @@ int acpi_device_set_power(struct acpi_device *device, int state)
 		dev_warn(&device->dev, "Failed to change power state to %s\n",
 			 acpi_power_state_string(state));
 	} else {
-		device->power.state = state;
+		device->power.state = target_state;
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Device [%s] transitioned to %s\n",
 				  device->pnp.bus_id,

drivers/cpufreq/cpufreq.c

@@ -1002,7 +1002,7 @@ static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
 	int ret = 0;
 
 	/* Some related CPUs might not be present (physically hotplugged) */
-	for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
+	for_each_cpu(j, policy->real_cpus) {
 		if (j == policy->kobj_cpu)
 			continue;
 
@@ -1019,7 +1019,7 @@ static void cpufreq_remove_dev_symlink(struct cpufreq_policy *policy)
 	unsigned int j;
 
 	/* Some related CPUs might not be present (physically hotplugged) */
-	for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
+	for_each_cpu(j, policy->real_cpus) {
 		if (j == policy->kobj_cpu)
 			continue;
 
@@ -1163,11 +1163,14 @@ static struct cpufreq_policy *cpufreq_policy_alloc(struct device *dev)
 	if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
 		goto err_free_cpumask;
 
+	if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
+		goto err_free_rcpumask;
+
 	ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &dev->kobj,
 				   "cpufreq");
 	if (ret) {
 		pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
-		goto err_free_rcpumask;
+		goto err_free_real_cpus;
 	}
 
 	INIT_LIST_HEAD(&policy->policy_list);
@@ -1184,6 +1187,8 @@ static struct cpufreq_policy *cpufreq_policy_alloc(struct device *dev)
 
 	return policy;
 
+err_free_real_cpus:
+	free_cpumask_var(policy->real_cpus);
 err_free_rcpumask:
 	free_cpumask_var(policy->related_cpus);
 err_free_cpumask:
@@ -1234,6 +1239,7 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
 	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 
 	cpufreq_policy_put_kobj(policy, notify);
+	free_cpumask_var(policy->real_cpus);
 	free_cpumask_var(policy->related_cpus);
 	free_cpumask_var(policy->cpus);
 	kfree(policy);
@@ -1258,14 +1264,17 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 
 	pr_debug("adding CPU %u\n", cpu);
 
+	if (cpu_is_offline(cpu)) {
 		/*
-	 * Only possible if 'cpu' wasn't physically present earlier and we are
-	 * here from subsys_interface add callback. A hotplug notifier will
-	 * follow and we will handle it like logical CPU hotplug then. For now,
-	 * just create the sysfs link.
+		 * Only possible if we are here from the subsys_interface add
+		 * callback.  A hotplug notifier will follow and we will handle
+		 * it as CPU online then.  For now, just create the sysfs link,
+		 * unless there is no policy or the link is already present.
 		 */
-	if (cpu_is_offline(cpu))
-		return add_cpu_dev_symlink(per_cpu(cpufreq_cpu_data, cpu), cpu);
+		policy = per_cpu(cpufreq_cpu_data, cpu);
+		return policy && !cpumask_test_and_set_cpu(cpu, policy->real_cpus)
+			? add_cpu_dev_symlink(policy, cpu) : 0;
+	}
 
 	if (!down_read_trylock(&cpufreq_rwsem))
 		return 0;
@@ -1307,6 +1316,10 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 	/* related cpus should atleast have policy->cpus */
 	cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
 
+	/* Remember which CPUs have been present at the policy creation time. */
+	if (!recover_policy)
+		cpumask_and(policy->real_cpus, policy->cpus, cpu_present_mask);
+
 	/*
 	 * affected cpus must always be the one, which are online. We aren't
 	 * managing offline cpus here.
@@ -1420,8 +1433,7 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
 	return ret;
 }
 
-static int __cpufreq_remove_dev_prepare(struct device *dev,
-					struct subsys_interface *sif)
+static int __cpufreq_remove_dev_prepare(struct device *dev)
 {
 	unsigned int cpu = dev->id;
 	int ret = 0;
@@ -1437,10 +1449,8 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 
 	if (has_target()) {
 		ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
-		if (ret) {
+		if (ret)
 			pr_err("%s: Failed to stop governor\n", __func__);
-			return ret;
-		}
 	}
 
 	down_write(&policy->rwsem);
@@ -1473,8 +1483,7 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
 	return ret;
 }
 
-static int __cpufreq_remove_dev_finish(struct device *dev,
-				       struct subsys_interface *sif)
+static int __cpufreq_remove_dev_finish(struct device *dev)
 {
 	unsigned int cpu = dev->id;
 	int ret;
@@ -1492,10 +1501,8 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 	/* If cpu is last user of policy, free policy */
 	if (has_target()) {
 		ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
-		if (ret) {
+		if (ret)
 			pr_err("%s: Failed to exit governor\n", __func__);
-			return ret;
-		}
 	}
 
 	/*
@@ -1506,10 +1513,6 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 	if (cpufreq_driver->exit)
 		cpufreq_driver->exit(policy);
 
-	/* Free the policy only if the driver is getting removed. */
-	if (sif)
-		cpufreq_policy_free(policy, true);
-
 	return 0;
 }
 
@@ -1521,42 +1524,41 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
 static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	unsigned int cpu = dev->id;
-	int ret;
-
-	/*
-	 * Only possible if 'cpu' is getting physically removed now. A hotplug
-	 * notifier should have already been called and we just need to remove
-	 * link or free policy here.
-	 */
-	if (cpu_is_offline(cpu)) {
 	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
-		struct cpumask mask;
 
 	if (!policy)
 		return 0;
 
-		cpumask_copy(&mask, policy->related_cpus);
-		cpumask_clear_cpu(cpu, &mask);
-
-		/*
-		 * Free policy only if all policy->related_cpus are removed
-		 * physically.
-		 */
-		if (cpumask_intersects(&mask, cpu_present_mask)) {
-			remove_cpu_dev_symlink(policy, cpu);
-			return 0;
+	if (cpu_online(cpu)) {
+		__cpufreq_remove_dev_prepare(dev);
+		__cpufreq_remove_dev_finish(dev);
 	}
 
+	cpumask_clear_cpu(cpu, policy->real_cpus);
+
+	if (cpumask_empty(policy->real_cpus)) {
 		cpufreq_policy_free(policy, true);
 		return 0;
 	}
 
-	ret = __cpufreq_remove_dev_prepare(dev, sif);
+	if (cpu != policy->kobj_cpu) {
+		remove_cpu_dev_symlink(policy, cpu);
+	} else {
+		/*
+		 * The CPU owning the policy object is going away.  Move it to
+		 * another suitable CPU.
+		 */
+		unsigned int new_cpu = cpumask_first(policy->real_cpus);
+		struct device *new_dev = get_cpu_device(new_cpu);
 
-	if (!ret)
-		ret = __cpufreq_remove_dev_finish(dev, sif);
+		dev_dbg(dev, "%s: Moving policy object to CPU%u\n", __func__, new_cpu);
 
-	return ret;
+		sysfs_remove_link(&new_dev->kobj, "cpufreq");
+		policy->kobj_cpu = new_cpu;
+		WARN_ON(kobject_move(&policy->kobj, &new_dev->kobj));
+	}
+
+	return 0;
 }
 
 static void handle_update(struct work_struct *work)
@@ -2395,11 +2397,11 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
 			break;
 
 		case CPU_DOWN_PREPARE:
-			__cpufreq_remove_dev_prepare(dev, NULL);
+			__cpufreq_remove_dev_prepare(dev);
 			break;
 
 		case CPU_POST_DEAD:
-			__cpufreq_remove_dev_finish(dev, NULL);
+			__cpufreq_remove_dev_finish(dev);
 			break;
 
 		case CPU_DOWN_FAILED:

drivers/cpufreq/intel_pstate.c

@@ -681,6 +681,7 @@ static struct cpu_defaults knl_params = {
 		.get_max = core_get_max_pstate,
 		.get_min = core_get_min_pstate,
 		.get_turbo = knl_get_turbo_pstate,
+		.get_scaling = core_get_scaling,
 		.set = core_set_pstate,
 	},
 };

include/linux/cpufreq.h

@@ -62,6 +62,7 @@ struct cpufreq_policy {
 	/* CPUs sharing clock, require sw coordination */
 	cpumask_var_t		cpus;	/* Online CPUs only */
 	cpumask_var_t		related_cpus; /* Online + Offline CPUs */
+	cpumask_var_t		real_cpus; /* Related and present */
 
 	unsigned int		shared_type; /* ACPI: ANY or ALL affected CPUs
 						should set cpufreq */