linux/drivers/acpi/processor_driver.c
Rafael J. Wysocki c0e0421a60 ACPI: processor: Reorder acpi_processor_driver_init()
The cpufreq policy notifier in the ACPI processor driver may as
well be registered before the driver itself, which causes
acpi_processor_cpufreq_init to be true (unless the notifier
registration fails, which is unlikely at that point) when the
ACPI CPU thermal cooling devices are registered, so the
processor_get_max_state() result does not change while
acpi_processor_driver_init() is running.

Change the ordering in acpi_processor_driver_init() accordingly
to prevent the max_state value from remaining 0 permanently for all
ACPI CPU cooling devices due to setting acpi_processor_cpufreq_init
too late.  [Note that processor_get_max_state() may still return
different values at different times after this change, depending on
the cpufreq driver registration time, but that issue needs to be
addressed separately.]

Fixes: a365105c685c("thermal: sysfs: Reuse cdev->max_state")
Reported-by: Wang, Quanxian <quanxian.wang@intel.com>
Link: https://lore.kernel.org/linux-pm/53ec1f06f61c984100868926f282647e57ecfb2d.camel@intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
2023-03-22 15:20:38 +01:00

312 lines
7.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* processor_driver.c - ACPI Processor Driver
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
* - Added processor hotplug support
* Copyright (C) 2013, Intel Corporation
* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include "internal.h"
#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
#define ACPI_PROCESSOR_NOTIFY_POWER 0x81
#define ACPI_PROCESSOR_NOTIFY_THROTTLING 0x82
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[] = {
{ACPI_PROCESSOR_OBJECT_HID, 0},
{ACPI_PROCESSOR_DEVICE_HID, 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, processor_device_ids);
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,
};
static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
{
struct acpi_device *device = data;
struct acpi_processor *pr;
int saved;
if (device->handle != handle)
return;
pr = acpi_driver_data(device);
if (!pr)
return;
switch (event) {
case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
saved = pr->performance_platform_limit;
acpi_processor_ppc_has_changed(pr, 1);
if (saved == pr->performance_platform_limit)
break;
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event,
pr->performance_platform_limit);
break;
case ACPI_PROCESSOR_NOTIFY_POWER:
acpi_processor_power_state_has_changed(pr);
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event, 0);
break;
case ACPI_PROCESSOR_NOTIFY_THROTTLING:
acpi_processor_tstate_has_changed(pr);
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event, 0);
break;
default:
acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
break;
}
return;
}
static int __acpi_processor_start(struct acpi_device *device);
static int acpi_soft_cpu_online(unsigned int cpu)
{
struct acpi_processor *pr = per_cpu(processors, cpu);
struct acpi_device *device;
if (!pr)
return 0;
device = acpi_fetch_acpi_dev(pr->handle);
if (!device)
return 0;
/*
* CPU got physically hotplugged and onlined for the first time:
* Initialize missing things.
*/
if (pr->flags.need_hotplug_init) {
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 {
/* Normal CPU soft online event. */
acpi_processor_ppc_has_changed(pr, 0);
acpi_processor_hotplug(pr);
acpi_processor_reevaluate_tstate(pr, false);
acpi_processor_tstate_has_changed(pr);
}
return 0;
}
static int acpi_soft_cpu_dead(unsigned int cpu)
{
struct acpi_processor *pr = per_cpu(processors, cpu);
if (!pr || !acpi_fetch_acpi_dev(pr->handle))
return 0;
acpi_processor_reevaluate_tstate(pr, true);
return 0;
}
#ifdef CONFIG_ACPI_CPU_FREQ_PSS
static void acpi_pss_perf_init(struct acpi_processor *pr)
{
acpi_processor_ppc_has_changed(pr, 0);
acpi_processor_get_throttling_info(pr);
if (pr->flags.throttling)
pr->flags.limit = 1;
}
#else
static inline void acpi_pss_perf_init(struct acpi_processor *pr) {}
#endif /* CONFIG_ACPI_CPU_FREQ_PSS */
static int __acpi_processor_start(struct acpi_device *device)
{
struct acpi_processor *pr = acpi_driver_data(device);
acpi_status status;
int result = 0;
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");
if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
acpi_processor_power_init(pr);
acpi_pss_perf_init(pr);
result = acpi_processor_thermal_init(pr, device);
if (result)
goto err_power_exit;
status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
acpi_processor_notify, device);
if (ACPI_SUCCESS(status))
return 0;
result = -ENODEV;
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);
struct acpi_processor *pr;
if (!device)
return 0;
acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
acpi_processor_notify);
pr = acpi_driver_data(device);
if (!pr)
return 0;
acpi_processor_power_exit(pr);
acpi_cppc_processor_exit(pr);
acpi_processor_thermal_exit(pr, device);
return 0;
}
bool acpi_processor_cpufreq_init;
static int acpi_processor_notifier(struct notifier_block *nb,
unsigned long event, void *data)
{
struct cpufreq_policy *policy = data;
if (event == CPUFREQ_CREATE_POLICY) {
acpi_thermal_cpufreq_init(policy);
acpi_processor_ppc_init(policy);
} else if (event == CPUFREQ_REMOVE_POLICY) {
acpi_processor_ppc_exit(policy);
acpi_thermal_cpufreq_exit(policy);
}
return 0;
}
static struct notifier_block acpi_processor_notifier_block = {
.notifier_call = acpi_processor_notifier,
};
/*
* We keep the driver loaded even when ACPI is not running.
* This is needed for the powernow-k8 driver, that works even without
* ACPI, but needs symbols from this driver
*/
static enum cpuhp_state hp_online;
static int __init acpi_processor_driver_init(void)
{
int result = 0;
if (acpi_disabled)
return 0;
if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
CPUFREQ_POLICY_NOTIFIER)) {
acpi_processor_cpufreq_init = true;
acpi_processor_ignore_ppc_init();
}
result = driver_register(&acpi_processor_driver);
if (result < 0)
return result;
result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"acpi/cpu-drv:online",
acpi_soft_cpu_online, NULL);
if (result < 0)
goto err;
hp_online = result;
cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
NULL, acpi_soft_cpu_dead);
acpi_processor_throttling_init();
return 0;
err:
driver_unregister(&acpi_processor_driver);
return result;
}
static void __exit acpi_processor_driver_exit(void)
{
if (acpi_disabled)
return;
if (acpi_processor_cpufreq_init) {
cpufreq_unregister_notifier(&acpi_processor_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
acpi_processor_cpufreq_init = false;
}
cpuhp_remove_state_nocalls(hp_online);
cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
driver_unregister(&acpi_processor_driver);
}
module_init(acpi_processor_driver_init);
module_exit(acpi_processor_driver_exit);
MODULE_ALIAS("processor");