linux-hardened/drivers/acpi/processor_driver.c
Thomas Gleixner 8153f9ac43 ACPI/processor: Replace racy task affinity logic
acpi_processor_get_throttling() requires to invoke the getter function on
the target CPU. This is achieved by temporarily setting the affinity of the
calling user space thread to the requested CPU and reset it to the original
affinity afterwards.

That's racy vs. CPU hotplug and concurrent affinity settings for that
thread resulting in code executing on the wrong CPU and overwriting the
new affinity setting.

acpi_processor_get_throttling() is invoked in two ways:

1) The CPU online callback, which is already running on the target CPU and
   obviously protected against hotplug and not affected by affinity
   settings.

2) The ACPI driver probe function, which is not protected against hotplug
   during modprobe.

Switch it over to work_on_cpu() and protect the probe function against CPU
hotplug.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-acpi@vger.kernel.org
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20170412201042.785920903@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-15 12:20:54 +02:00

350 lines
8.8 KiB
C

/*
* 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>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#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
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_driver");
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_DEBUG_PRINT((ACPI_DB_INFO,
"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 || acpi_bus_get_device(pr->handle, &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);
struct acpi_device *device;
if (!pr || acpi_bus_get_device(pr->handle, &device))
return 0;
acpi_processor_reevaluate_tstate(pr, true);
return 0;
}
#ifdef CONFIG_ACPI_CPU_FREQ_PSS
static int acpi_pss_perf_init(struct acpi_processor *pr,
struct acpi_device *device)
{
int result = 0;
acpi_processor_ppc_has_changed(pr, 0);
acpi_processor_get_throttling_info(pr);
if (pr->flags.throttling)
pr->flags.limit = 1;
pr->cdev = thermal_cooling_device_register("Processor", device,
&processor_cooling_ops);
if (IS_ERR(pr->cdev)) {
result = PTR_ERR(pr->cdev);
return result;
}
dev_dbg(&device->dev, "registered as cooling_device%d\n",
pr->cdev->id);
result = sysfs_create_link(&device->dev.kobj,
&pr->cdev->device.kobj,
"thermal_cooling");
if (result) {
dev_err(&device->dev,
"Failed to create sysfs link 'thermal_cooling'\n");
goto err_thermal_unregister;
}
result = sysfs_create_link(&pr->cdev->device.kobj,
&device->dev.kobj,
"device");
if (result) {
dev_err(&pr->cdev->device,
"Failed to create sysfs link 'device'\n");
goto err_remove_sysfs_thermal;
}
return 0;
err_remove_sysfs_thermal:
sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
err_thermal_unregister:
thermal_cooling_device_unregister(pr->cdev);
return result;
}
static void acpi_pss_perf_exit(struct acpi_processor *pr,
struct acpi_device *device)
{
if (pr->cdev) {
sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
sysfs_remove_link(&pr->cdev->device.kobj, "device");
thermal_cooling_device_unregister(pr->cdev);
pr->cdev = NULL;
}
}
#else
static inline int acpi_pss_perf_init(struct acpi_processor *pr,
struct acpi_device *device)
{
return 0;
}
static inline void acpi_pss_perf_exit(struct acpi_processor *pr,
struct acpi_device *device) {}
#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_warn(&device->dev, "CPPC data invalid or not present\n");
if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
acpi_processor_power_init(pr);
result = acpi_pss_perf_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_pss_perf_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 */
get_online_cpus();
ret = __acpi_processor_start(device);
put_online_cpus();
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_pss_perf_exit(pr, device);
acpi_cppc_processor_exit(pr);
return 0;
}
/*
* 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;
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_thermal_cpufreq_init();
acpi_processor_ppc_init();
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;
acpi_processor_ppc_exit();
acpi_thermal_cpufreq_exit();
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");