Merge branch 'for-next/vcpu-hotplug' into for-next/core

* for-next/vcpu-hotplug: (21 commits)
  : arm64 support for virtual CPU hotplug (ACPI)
  irqchip/gic-v3: Fix 'broken_rdists' unused warning when !SMP and !ACPI
  arm64: Kconfig: Fix dependencies to enable ACPI_HOTPLUG_CPU
  cpumask: Add enabled cpumask for present CPUs that can be brought online
  arm64: document virtual CPU hotplug's expectations
  arm64: Kconfig: Enable hotplug CPU on arm64 if ACPI_PROCESSOR is enabled.
  arm64: arch_register_cpu() variant to check if an ACPI handle is now available.
  arm64: psci: Ignore DENIED CPUs
  irqchip/gic-v3: Add support for ACPI's disabled but 'online capable' CPUs
  irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc()
  arm64: acpi: Harden get_cpu_for_acpi_id() against missing CPU entry
  arm64: acpi: Move get_cpu_for_acpi_id() to a header
  ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug
  ACPI: scan: switch to flags for acpi_scan_check_and_detach()
  ACPI: processor: Register deferred CPUs from acpi_processor_get_info()
  ACPI: processor: Add acpi_get_processor_handle() helper
  ACPI: processor: Move checks and availability of acpi_processor earlier
  ACPI: processor: Fix memory leaks in error paths of processor_add()
  ACPI: processor: Return an error if acpi_processor_get_info() fails in processor_add()
  ACPI: processor: Drop duplicated check on _STA (enabled + present)
  cpu: Do not warn on arch_register_cpu() returning -EPROBE_DEFER
  ...

4 files changed, 134 insertions, 100 deletions

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 7a0dd35d62c9..64e10bad8072 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -35,6 +35,17 @@ EXPORT_PER_CPU_SYMBOL(processors);
 struct acpi_processor_errata errata __read_mostly;
 EXPORT_SYMBOL_GPL(errata);
 
+acpi_handle acpi_get_processor_handle(int cpu)
+{
+	struct acpi_processor *pr;
+
+	pr = per_cpu(processors, cpu);
+	if (pr)
+		return pr->handle;
+
+	return NULL;
+}
+
 static int acpi_processor_errata_piix4(struct pci_dev *dev)
 {
 	u8 value1 = 0;
@@ -183,20 +194,44 @@ static void __init acpi_pcc_cpufreq_init(void) {}
 #endif /* CONFIG_X86 */
 
 /* Initialization */
+static DEFINE_PER_CPU(void *, processor_device_array);
+
+static int acpi_processor_set_per_cpu(struct acpi_processor *pr,
+				      struct acpi_device *device)
+{
+	BUG_ON(pr->id >= nr_cpu_ids);
+
+	/*
+	 * Buggy BIOS check.
+	 * ACPI id of processors can be reported wrongly by the BIOS.
+	 * Don't trust it blindly
+	 */
+	if (per_cpu(processor_device_array, pr->id) != NULL &&
+	    per_cpu(processor_device_array, pr->id) != device) {
+		dev_warn(&device->dev,
+			 "BIOS reported wrong ACPI id %d for the processor\n",
+			 pr->id);
+		return -EINVAL;
+	}
+	/*
+	 * processor_device_array is not cleared on errors to allow buggy BIOS
+	 * checks.
+	 */
+	per_cpu(processor_device_array, pr->id) = device;
+	per_cpu(processors, pr->id) = pr;
+
+	return 0;
+}
+
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
-static int acpi_processor_hotadd_init(struct acpi_processor *pr)
+static int acpi_processor_hotadd_init(struct acpi_processor *pr,
+				      struct acpi_device *device)
 {
-	unsigned long long sta;
-	acpi_status status;
 	int ret;
 
 	if (invalid_phys_cpuid(pr->phys_id))
 		return -ENODEV;
 
-	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
-	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
-		return -ENODEV;
-
 	cpu_maps_update_begin();
 	cpus_write_lock();
 
@@ -204,19 +239,26 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
 	if (ret)
 		goto out;
 
+	ret = acpi_processor_set_per_cpu(pr, device);
+	if (ret) {
+		acpi_unmap_cpu(pr->id);
+		goto out;
+	}
+
 	ret = arch_register_cpu(pr->id);
 	if (ret) {
+		/* Leave the processor device array in place to detect buggy bios */
+		per_cpu(processors, pr->id) = NULL;
 		acpi_unmap_cpu(pr->id);
 		goto out;
 	}
 
 	/*
-	 * CPU got hot-added, but cpu_data is not initialized yet.  Set a flag
-	 * to delay cpu_idle/throttling initialization and do it when the CPU
-	 * gets online for the first time.
+	 * CPU got hot-added, but cpu_data is not initialized yet. Do
+	 * cpu_idle/throttling initialization when the CPU gets online for
+	 * the first time.
 	 */
 	pr_info("CPU%d has been hot-added\n", pr->id);
-	pr->flags.need_hotplug_init = 1;
 
 out:
 	cpus_write_unlock();
@@ -224,7 +266,8 @@ out:
 	return ret;
 }
 #else
-static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
+static inline int acpi_processor_hotadd_init(struct acpi_processor *pr,
+					     struct acpi_device *device)
 {
 	return -ENODEV;
 }
@@ -239,6 +282,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	acpi_status status = AE_OK;
 	static int cpu0_initialized;
 	unsigned long long value;
+	int ret;
 
 	acpi_processor_errata();
 
@@ -315,19 +359,19 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	}
 
 	/*
-	 *  Extra Processor objects may be enumerated on MP systems with
-	 *  less than the max # of CPUs. They should be ignored _iff
-	 *  they are physically not present.
-	 *
-	 *  NOTE: Even if the processor has a cpuid, it may not be present
-	 *  because cpuid <-> apicid mapping is persistent now.
+	 *  This code is not called unless we know the CPU is present and
+	 *  enabled. The two paths are:
+	 *  a) Initially present CPUs on architectures that do not defer
+	 *     their arch_register_cpu() calls until this point.
+	 *  b) Hotplugged CPUs (enabled bit in _STA has transitioned from not
+	 *     enabled to enabled)
 	 */
-	if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
-		int ret = acpi_processor_hotadd_init(pr);
-
-		if (ret)
-			return ret;
-	}
+	if (!get_cpu_device(pr->id))
+		ret = acpi_processor_hotadd_init(pr, device);
+	else
+		ret = acpi_processor_set_per_cpu(pr, device);
+	if (ret)
+		return ret;
 
 	/*
 	 * On some boxes several processors use the same processor bus id.
@@ -372,8 +416,6 @@ static int acpi_processor_get_info(struct acpi_device *device)
  * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
  * Such things have to be put in and set up by the processor driver's .probe().
  */
-static DEFINE_PER_CPU(void *, processor_device_array);
-
 static int acpi_processor_add(struct acpi_device *device,
 					const struct acpi_device_id *id)
 {
@@ -400,39 +442,17 @@ static int acpi_processor_add(struct acpi_device *device,
 
 	result = acpi_processor_get_info(device);
 	if (result) /* Processor is not physically present or unavailable */
-		return 0;
-
-	BUG_ON(pr->id >= nr_cpu_ids);
-
-	/*
-	 * Buggy BIOS check.
-	 * ACPI id of processors can be reported wrongly by the BIOS.
-	 * Don't trust it blindly
-	 */
-	if (per_cpu(processor_device_array, pr->id) != NULL &&
-	    per_cpu(processor_device_array, pr->id) != device) {
-		dev_warn(&device->dev,
-			"BIOS reported wrong ACPI id %d for the processor\n",
-			pr->id);
-		/* Give up, but do not abort the namespace scan. */
-		goto err;
-	}
-	/*
-	 * processor_device_array is not cleared on errors to allow buggy BIOS
-	 * checks.
-	 */
-	per_cpu(processor_device_array, pr->id) = device;
-	per_cpu(processors, pr->id) = pr;
+		goto err_clear_driver_data;
 
 	dev = get_cpu_device(pr->id);
 	if (!dev) {
 		result = -ENODEV;
-		goto err;
+		goto err_clear_per_cpu;
 	}
 
 	result = acpi_bind_one(dev, device);
 	if (result)
-		goto err;
+		goto err_clear_per_cpu;
 
 	pr->dev = dev;
 
@@ -443,10 +463,11 @@ static int acpi_processor_add(struct acpi_device *device,
 	dev_err(dev, "Processor driver could not be attached\n");
 	acpi_unbind_one(dev);
 
- err:
-	free_cpumask_var(pr->throttling.shared_cpu_map);
-	device->driver_data = NULL;
+ err_clear_per_cpu:
 	per_cpu(processors, pr->id) = NULL;
+ err_clear_driver_data:
+	device->driver_data = NULL;
+	free_cpumask_var(pr->throttling.shared_cpu_map);
  err_free_pr:
 	kfree(pr);
 	return result;
@@ -454,7 +475,7 @@ static int acpi_processor_add(struct acpi_device *device,
 
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 /* Removal */
-static void acpi_processor_remove(struct acpi_device *device)
+static void acpi_processor_post_eject(struct acpi_device *device)
 {
 	struct acpi_processor *pr;
 
@@ -476,10 +497,6 @@ static void acpi_processor_remove(struct acpi_device *device)
 	device_release_driver(pr->dev);
 	acpi_unbind_one(pr->dev);
 
-	/* Clean up. */
-	per_cpu(processor_device_array, pr->id) = NULL;
-	per_cpu(processors, pr->id) = NULL;
-
 	cpu_maps_update_begin();
 	cpus_write_lock();
 
@@ -487,6 +504,10 @@ static void acpi_processor_remove(struct acpi_device *device)
 	arch_unregister_cpu(pr->id);
 	acpi_unmap_cpu(pr->id);
 
+	/* Clean up. */
+	per_cpu(processor_device_array, pr->id) = NULL;
+	per_cpu(processors, pr->id) = NULL;
+
 	cpus_write_unlock();
 	cpu_maps_update_done();
 
@@ -622,7 +643,7 @@ static struct acpi_scan_handler processor_handler = {
 	.ids = processor_device_ids,
 	.attach = acpi_processor_add,
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
-	.detach = acpi_processor_remove,
+	.post_eject = acpi_processor_post_eject,
 #endif
 	.hotplug = {
 		.enabled = true,
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index b203cfe28550..b04b684f3190 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -90,7 +90,8 @@ static int map_gicc_mpidr(struct acpi_subtable_header *entry,
 	struct acpi_madt_generic_interrupt *gicc =
 	    container_of(entry, struct acpi_madt_generic_interrupt, header);
 
-	if (!acpi_gicc_is_usable(gicc))
+	if (!(gicc->flags &
+	      (ACPI_MADT_ENABLED | ACPI_MADT_GICC_ONLINE_CAPABLE)))
 		return -ENODEV;
 
 	/* device_declaration means Device object in DSDT, in the
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 67db60eda370..cb52dd000b95 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -33,7 +33,6 @@ MODULE_AUTHOR("Paul Diefenbaugh");
 MODULE_DESCRIPTION("ACPI Processor Driver");
 MODULE_LICENSE("GPL");
 
-static int acpi_processor_start(struct device *dev);
 static int acpi_processor_stop(struct device *dev);
 
 static const struct acpi_device_id processor_device_ids[] = {
@@ -47,7 +46,6 @@ static struct device_driver acpi_processor_driver = {
 	.name = "processor",
 	.bus = &cpu_subsys,
 	.acpi_match_table = processor_device_ids,
-	.probe = acpi_processor_start,
 	.remove = acpi_processor_stop,
 };
 
@@ -115,12 +113,9 @@ static int acpi_soft_cpu_online(unsigned int cpu)
 	 * CPU got physically hotplugged and onlined for the first time:
 	 * Initialize missing things.
 	 */
-	if (pr->flags.need_hotplug_init) {
+	if (!pr->flags.previously_online) {
 		int ret;
 
-		pr_info("Will online and init hotplugged CPU: %d\n",
-			pr->id);
-		pr->flags.need_hotplug_init = 0;
 		ret = __acpi_processor_start(device);
 		WARN(ret, "Failed to start CPU: %d\n", pr->id);
 	} else {
@@ -167,9 +162,6 @@ static int __acpi_processor_start(struct acpi_device *device)
 	if (!pr)
 		return -ENODEV;
 
-	if (pr->flags.need_hotplug_init)
-		return 0;
-
 	result = acpi_cppc_processor_probe(pr);
 	if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
 		dev_dbg(&device->dev, "CPPC data invalid or not present\n");
@@ -185,32 +177,21 @@ static int __acpi_processor_start(struct acpi_device *device)
 
 	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
 					     acpi_processor_notify, device);
-	if (ACPI_SUCCESS(status))
-		return 0;
+	if (!ACPI_SUCCESS(status)) {
+		result = -ENODEV;
+		goto err_thermal_exit;
+	}
+	pr->flags.previously_online = 1;
 
-	result = -ENODEV;
-	acpi_processor_thermal_exit(pr, device);
+	return 0;
 
+err_thermal_exit:
+	acpi_processor_thermal_exit(pr, device);
 err_power_exit:
 	acpi_processor_power_exit(pr);
 	return result;
 }
 
-static int acpi_processor_start(struct device *dev)
-{
-	struct acpi_device *device = ACPI_COMPANION(dev);
-	int ret;
-
-	if (!device)
-		return -ENODEV;
-
-	/* Protect against concurrent CPU hotplug operations */
-	cpu_hotplug_disable();
-	ret = __acpi_processor_start(device);
-	cpu_hotplug_enable();
-	return ret;
-}
-
 static int acpi_processor_stop(struct device *dev)
 {
 	struct acpi_device *device = ACPI_COMPANION(dev);
@@ -279,9 +260,9 @@ static int __init acpi_processor_driver_init(void)
 	if (result < 0)
 		return result;
 
-	result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
-					   "acpi/cpu-drv:online",
-					   acpi_soft_cpu_online, NULL);
+	result = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+				   "acpi/cpu-drv:online",
+				   acpi_soft_cpu_online, NULL);
 	if (result < 0)
 		goto err;
 	hp_online = result;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 503773707e01..0aa20623525a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -243,13 +243,17 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
 	return 0;
 }
 
-static int acpi_scan_check_and_detach(struct acpi_device *adev, void *check)
+#define ACPI_SCAN_CHECK_FLAG_STATUS	BIT(0)
+#define ACPI_SCAN_CHECK_FLAG_EJECT	BIT(1)
+
+static int acpi_scan_check_and_detach(struct acpi_device *adev, void *p)
 {
 	struct acpi_scan_handler *handler = adev->handler;
+	uintptr_t flags = (uintptr_t)p;
 
-	acpi_dev_for_each_child_reverse(adev, acpi_scan_check_and_detach, check);
+	acpi_dev_for_each_child_reverse(adev, acpi_scan_check_and_detach, p);
 
-	if (check) {
+	if (flags & ACPI_SCAN_CHECK_FLAG_STATUS) {
 		acpi_bus_get_status(adev);
 		/*
 		 * Skip devices that are still there and take the enabled
@@ -269,8 +273,6 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *check)
 	if (handler) {
 		if (handler->detach)
 			handler->detach(adev);
-
-		adev->handler = NULL;
 	} else {
 		device_release_driver(&adev->dev);
 	}
@@ -280,6 +282,28 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *check)
 	 */
 	acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
 	adev->flags.initialized = false;
+
+	/* For eject this is deferred to acpi_bus_post_eject() */
+	if (!(flags & ACPI_SCAN_CHECK_FLAG_EJECT)) {
+		adev->handler = NULL;
+		acpi_device_clear_enumerated(adev);
+	}
+	return 0;
+}
+
+static int acpi_bus_post_eject(struct acpi_device *adev, void *not_used)
+{
+	struct acpi_scan_handler *handler = adev->handler;
+
+	acpi_dev_for_each_child_reverse(adev, acpi_bus_post_eject, NULL);
+
+	if (handler) {
+		if (handler->post_eject)
+			handler->post_eject(adev);
+
+		adev->handler = NULL;
+	}
+
 	acpi_device_clear_enumerated(adev);
 
 	return 0;
@@ -287,7 +311,9 @@ static int acpi_scan_check_and_detach(struct acpi_device *adev, void *check)
 
 static void acpi_scan_check_subtree(struct acpi_device *adev)
 {
-	acpi_scan_check_and_detach(adev, (void *)true);
+	uintptr_t flags = ACPI_SCAN_CHECK_FLAG_STATUS;
+
+	acpi_scan_check_and_detach(adev, (void *)flags);
 }
 
 static int acpi_scan_hot_remove(struct acpi_device *device)
@@ -295,6 +321,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
 	acpi_handle handle = device->handle;
 	unsigned long long sta;
 	acpi_status status;
+	uintptr_t flags = ACPI_SCAN_CHECK_FLAG_EJECT;
 
 	if (device->handler && device->handler->hotplug.demand_offline) {
 		if (!acpi_scan_is_offline(device, true))
@@ -307,7 +334,7 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
 
 	acpi_handle_debug(handle, "Ejecting\n");
 
-	acpi_bus_trim(device);
+	acpi_scan_check_and_detach(device, (void *)flags);
 
 	acpi_evaluate_lck(handle, 0);
 	/*
@@ -330,6 +357,8 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
 	} else if (sta & ACPI_STA_DEVICE_ENABLED) {
 		acpi_handle_warn(handle,
 			"Eject incomplete - status 0x%llx\n", sta);
+	} else {
+		acpi_bus_post_eject(device, NULL);
 	}
 
 	return 0;
@@ -2596,7 +2625,9 @@ EXPORT_SYMBOL(acpi_bus_scan);
  */
 void acpi_bus_trim(struct acpi_device *adev)
 {
-	acpi_scan_check_and_detach(adev, NULL);
+	uintptr_t flags = 0;
+
+	acpi_scan_check_and_detach(adev, (void *)flags);
 }
 EXPORT_SYMBOL_GPL(acpi_bus_trim);