https://github.com/torvalds/linux
Tip revision: 7c60610d476766e128cc4284bb6349732cbd6606 authored by Linus Torvalds on 15 August 2021, 23:40:53 UTC
Linux 5.14-rc6
Linux 5.14-rc6
Tip revision: 7c60610
therm_throt.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Thermal throttle event support code (such as syslog messaging and rate
* limiting) that was factored out from x86_64 (mce_intel.c) and i386 (p4.c).
*
* This allows consistent reporting of CPU thermal throttle events.
*
* Maintains a counter in /sys that keeps track of the number of thermal
* events, such that the user knows how bad the thermal problem might be
* (since the logging to syslog is rate limited).
*
* Author: Dmitriy Zavin (dmitriyz@google.com)
*
* Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c.
* Inspired by Ross Biro's and Al Borchers' counter code.
*/
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <asm/processor.h>
#include <asm/thermal.h>
#include <asm/traps.h>
#include <asm/apic.h>
#include <asm/irq.h>
#include <asm/msr.h>
#include "thermal_interrupt.h"
/* How long to wait between reporting thermal events */
#define CHECK_INTERVAL (300 * HZ)
#define THERMAL_THROTTLING_EVENT 0
#define POWER_LIMIT_EVENT 1
/**
* struct _thermal_state - Represent the current thermal event state
* @next_check: Stores the next timestamp, when it is allowed
* to log the next warning message.
* @last_interrupt_time: Stores the timestamp for the last threshold
* high event.
* @therm_work: Delayed workqueue structure
* @count: Stores the current running count for thermal
* or power threshold interrupts.
* @last_count: Stores the previous running count for thermal
* or power threshold interrupts.
* @max_time_ms: This shows the maximum amount of time CPU was
* in throttled state for a single thermal
* threshold high to low state.
* @total_time_ms: This is a cumulative time during which CPU was
* in the throttled state.
* @rate_control_active: Set when a throttling message is logged.
* This is used for the purpose of rate-control.
* @new_event: Stores the last high/low status of the
* THERM_STATUS_PROCHOT or
* THERM_STATUS_POWER_LIMIT.
* @level: Stores whether this _thermal_state instance is
* for a CORE level or for PACKAGE level.
* @sample_index: Index for storing the next sample in the buffer
* temp_samples[].
* @sample_count: Total number of samples collected in the buffer
* temp_samples[].
* @average: The last moving average of temperature samples
* @baseline_temp: Temperature at which thermal threshold high
* interrupt was generated.
* @temp_samples: Storage for temperature samples to calculate
* moving average.
*
* This structure is used to represent data related to thermal state for a CPU.
* There is a separate storage for core and package level for each CPU.
*/
struct _thermal_state {
u64 next_check;
u64 last_interrupt_time;
struct delayed_work therm_work;
unsigned long count;
unsigned long last_count;
unsigned long max_time_ms;
unsigned long total_time_ms;
bool rate_control_active;
bool new_event;
u8 level;
u8 sample_index;
u8 sample_count;
u8 average;
u8 baseline_temp;
u8 temp_samples[3];
};
struct thermal_state {
struct _thermal_state core_throttle;
struct _thermal_state core_power_limit;
struct _thermal_state package_throttle;
struct _thermal_state package_power_limit;
struct _thermal_state core_thresh0;
struct _thermal_state core_thresh1;
struct _thermal_state pkg_thresh0;
struct _thermal_state pkg_thresh1;
};
/* Callback to handle core threshold interrupts */
int (*platform_thermal_notify)(__u64 msr_val);
EXPORT_SYMBOL(platform_thermal_notify);
/* Callback to handle core package threshold_interrupts */
int (*platform_thermal_package_notify)(__u64 msr_val);
EXPORT_SYMBOL_GPL(platform_thermal_package_notify);
/* Callback support of rate control, return true, if
* callback has rate control */
bool (*platform_thermal_package_rate_control)(void);
EXPORT_SYMBOL_GPL(platform_thermal_package_rate_control);
static DEFINE_PER_CPU(struct thermal_state, thermal_state);
static atomic_t therm_throt_en = ATOMIC_INIT(0);
static u32 lvtthmr_init __read_mostly;
#ifdef CONFIG_SYSFS
#define define_therm_throt_device_one_ro(_name) \
static DEVICE_ATTR(_name, 0444, \
therm_throt_device_show_##_name, \
NULL) \
#define define_therm_throt_device_show_func(event, name) \
\
static ssize_t therm_throt_device_show_##event##_##name( \
struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
unsigned int cpu = dev->id; \
ssize_t ret; \
\
preempt_disable(); /* CPU hotplug */ \
if (cpu_online(cpu)) { \
ret = sprintf(buf, "%lu\n", \
per_cpu(thermal_state, cpu).event.name); \
} else \
ret = 0; \
preempt_enable(); \
\
return ret; \
}
define_therm_throt_device_show_func(core_throttle, count);
define_therm_throt_device_one_ro(core_throttle_count);
define_therm_throt_device_show_func(core_power_limit, count);
define_therm_throt_device_one_ro(core_power_limit_count);
define_therm_throt_device_show_func(package_throttle, count);
define_therm_throt_device_one_ro(package_throttle_count);
define_therm_throt_device_show_func(package_power_limit, count);
define_therm_throt_device_one_ro(package_power_limit_count);
define_therm_throt_device_show_func(core_throttle, max_time_ms);
define_therm_throt_device_one_ro(core_throttle_max_time_ms);
define_therm_throt_device_show_func(package_throttle, max_time_ms);
define_therm_throt_device_one_ro(package_throttle_max_time_ms);
define_therm_throt_device_show_func(core_throttle, total_time_ms);
define_therm_throt_device_one_ro(core_throttle_total_time_ms);
define_therm_throt_device_show_func(package_throttle, total_time_ms);
define_therm_throt_device_one_ro(package_throttle_total_time_ms);
static struct attribute *thermal_throttle_attrs[] = {
&dev_attr_core_throttle_count.attr,
&dev_attr_core_throttle_max_time_ms.attr,
&dev_attr_core_throttle_total_time_ms.attr,
NULL
};
static const struct attribute_group thermal_attr_group = {
.attrs = thermal_throttle_attrs,
.name = "thermal_throttle"
};
#endif /* CONFIG_SYSFS */
#define CORE_LEVEL 0
#define PACKAGE_LEVEL 1
#define THERM_THROT_POLL_INTERVAL HZ
#define THERM_STATUS_PROCHOT_LOG BIT(1)
#define THERM_STATUS_CLEAR_CORE_MASK (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11) | BIT(13) | BIT(15))
#define THERM_STATUS_CLEAR_PKG_MASK (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11))
static void clear_therm_status_log(int level)
{
int msr;
u64 mask, msr_val;
if (level == CORE_LEVEL) {
msr = MSR_IA32_THERM_STATUS;
mask = THERM_STATUS_CLEAR_CORE_MASK;
} else {
msr = MSR_IA32_PACKAGE_THERM_STATUS;
mask = THERM_STATUS_CLEAR_PKG_MASK;
}
rdmsrl(msr, msr_val);
msr_val &= mask;
wrmsrl(msr, msr_val & ~THERM_STATUS_PROCHOT_LOG);
}
static void get_therm_status(int level, bool *proc_hot, u8 *temp)
{
int msr;
u64 msr_val;
if (level == CORE_LEVEL)
msr = MSR_IA32_THERM_STATUS;
else
msr = MSR_IA32_PACKAGE_THERM_STATUS;
rdmsrl(msr, msr_val);
if (msr_val & THERM_STATUS_PROCHOT_LOG)
*proc_hot = true;
else
*proc_hot = false;
*temp = (msr_val >> 16) & 0x7F;
}
static void __maybe_unused throttle_active_work(struct work_struct *work)
{
struct _thermal_state *state = container_of(to_delayed_work(work),
struct _thermal_state, therm_work);
unsigned int i, avg, this_cpu = smp_processor_id();
u64 now = get_jiffies_64();
bool hot;
u8 temp;
get_therm_status(state->level, &hot, &temp);
/* temperature value is offset from the max so lesser means hotter */
if (!hot && temp > state->baseline_temp) {
if (state->rate_control_active)
pr_info("CPU%d: %s temperature/speed normal (total events = %lu)\n",
this_cpu,
state->level == CORE_LEVEL ? "Core" : "Package",
state->count);
state->rate_control_active = false;
return;
}
if (time_before64(now, state->next_check) &&
state->rate_control_active)
goto re_arm;
state->next_check = now + CHECK_INTERVAL;
if (state->count != state->last_count) {
/* There was one new thermal interrupt */
state->last_count = state->count;
state->average = 0;
state->sample_count = 0;
state->sample_index = 0;
}
state->temp_samples[state->sample_index] = temp;
state->sample_count++;
state->sample_index = (state->sample_index + 1) % ARRAY_SIZE(state->temp_samples);
if (state->sample_count < ARRAY_SIZE(state->temp_samples))
goto re_arm;
avg = 0;
for (i = 0; i < ARRAY_SIZE(state->temp_samples); ++i)
avg += state->temp_samples[i];
avg /= ARRAY_SIZE(state->temp_samples);
if (state->average > avg) {
pr_warn("CPU%d: %s temperature is above threshold, cpu clock is throttled (total events = %lu)\n",
this_cpu,
state->level == CORE_LEVEL ? "Core" : "Package",
state->count);
state->rate_control_active = true;
}
state->average = avg;
re_arm:
clear_therm_status_log(state->level);
schedule_delayed_work_on(this_cpu, &state->therm_work, THERM_THROT_POLL_INTERVAL);
}
/***
* therm_throt_process - Process thermal throttling event from interrupt
* @curr: Whether the condition is current or not (boolean), since the
* thermal interrupt normally gets called both when the thermal
* event begins and once the event has ended.
*
* This function is called by the thermal interrupt after the
* IRQ has been acknowledged.
*
* It will take care of rate limiting and printing messages to the syslog.
*/
static void therm_throt_process(bool new_event, int event, int level)
{
struct _thermal_state *state;
unsigned int this_cpu = smp_processor_id();
bool old_event;
u64 now;
struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
now = get_jiffies_64();
if (level == CORE_LEVEL) {
if (event == THERMAL_THROTTLING_EVENT)
state = &pstate->core_throttle;
else if (event == POWER_LIMIT_EVENT)
state = &pstate->core_power_limit;
else
return;
} else if (level == PACKAGE_LEVEL) {
if (event == THERMAL_THROTTLING_EVENT)
state = &pstate->package_throttle;
else if (event == POWER_LIMIT_EVENT)
state = &pstate->package_power_limit;
else
return;
} else
return;
old_event = state->new_event;
state->new_event = new_event;
if (new_event)
state->count++;
if (event != THERMAL_THROTTLING_EVENT)
return;
if (new_event && !state->last_interrupt_time) {
bool hot;
u8 temp;
get_therm_status(state->level, &hot, &temp);
/*
* Ignore short temperature spike as the system is not close
* to PROCHOT. 10C offset is large enough to ignore. It is
* already dropped from the high threshold temperature.
*/
if (temp > 10)
return;
state->baseline_temp = temp;
state->last_interrupt_time = now;
schedule_delayed_work_on(this_cpu, &state->therm_work, THERM_THROT_POLL_INTERVAL);
} else if (old_event && state->last_interrupt_time) {
unsigned long throttle_time;
throttle_time = jiffies_delta_to_msecs(now - state->last_interrupt_time);
if (throttle_time > state->max_time_ms)
state->max_time_ms = throttle_time;
state->total_time_ms += throttle_time;
state->last_interrupt_time = 0;
}
}
static int thresh_event_valid(int level, int event)
{
struct _thermal_state *state;
unsigned int this_cpu = smp_processor_id();
struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
u64 now = get_jiffies_64();
if (level == PACKAGE_LEVEL)
state = (event == 0) ? &pstate->pkg_thresh0 :
&pstate->pkg_thresh1;
else
state = (event == 0) ? &pstate->core_thresh0 :
&pstate->core_thresh1;
if (time_before64(now, state->next_check))
return 0;
state->next_check = now + CHECK_INTERVAL;
return 1;
}
static bool int_pln_enable;
static int __init int_pln_enable_setup(char *s)
{
int_pln_enable = true;
return 1;
}
__setup("int_pln_enable", int_pln_enable_setup);
#ifdef CONFIG_SYSFS
/* Add/Remove thermal_throttle interface for CPU device: */
static int thermal_throttle_add_dev(struct device *dev, unsigned int cpu)
{
int err;
struct cpuinfo_x86 *c = &cpu_data(cpu);
err = sysfs_create_group(&dev->kobj, &thermal_attr_group);
if (err)
return err;
if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable) {
err = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_core_power_limit_count.attr,
thermal_attr_group.name);
if (err)
goto del_group;
}
if (cpu_has(c, X86_FEATURE_PTS)) {
err = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_package_throttle_count.attr,
thermal_attr_group.name);
if (err)
goto del_group;
err = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_package_throttle_max_time_ms.attr,
thermal_attr_group.name);
if (err)
goto del_group;
err = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_package_throttle_total_time_ms.attr,
thermal_attr_group.name);
if (err)
goto del_group;
if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable) {
err = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_package_power_limit_count.attr,
thermal_attr_group.name);
if (err)
goto del_group;
}
}
return 0;
del_group:
sysfs_remove_group(&dev->kobj, &thermal_attr_group);
return err;
}
static void thermal_throttle_remove_dev(struct device *dev)
{
sysfs_remove_group(&dev->kobj, &thermal_attr_group);
}
/* Get notified when a cpu comes on/off. Be hotplug friendly. */
static int thermal_throttle_online(unsigned int cpu)
{
struct thermal_state *state = &per_cpu(thermal_state, cpu);
struct device *dev = get_cpu_device(cpu);
u32 l;
state->package_throttle.level = PACKAGE_LEVEL;
state->core_throttle.level = CORE_LEVEL;
INIT_DELAYED_WORK(&state->package_throttle.therm_work, throttle_active_work);
INIT_DELAYED_WORK(&state->core_throttle.therm_work, throttle_active_work);
/* Unmask the thermal vector after the above workqueues are initialized. */
l = apic_read(APIC_LVTTHMR);
apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
return thermal_throttle_add_dev(dev, cpu);
}
static int thermal_throttle_offline(unsigned int cpu)
{
struct thermal_state *state = &per_cpu(thermal_state, cpu);
struct device *dev = get_cpu_device(cpu);
u32 l;
/* Mask the thermal vector before draining evtl. pending work */
l = apic_read(APIC_LVTTHMR);
apic_write(APIC_LVTTHMR, l | APIC_LVT_MASKED);
cancel_delayed_work_sync(&state->package_throttle.therm_work);
cancel_delayed_work_sync(&state->core_throttle.therm_work);
state->package_throttle.rate_control_active = false;
state->core_throttle.rate_control_active = false;
thermal_throttle_remove_dev(dev);
return 0;
}
static __init int thermal_throttle_init_device(void)
{
int ret;
if (!atomic_read(&therm_throt_en))
return 0;
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/therm:online",
thermal_throttle_online,
thermal_throttle_offline);
return ret < 0 ? ret : 0;
}
device_initcall(thermal_throttle_init_device);
#endif /* CONFIG_SYSFS */
static void notify_package_thresholds(__u64 msr_val)
{
bool notify_thres_0 = false;
bool notify_thres_1 = false;
if (!platform_thermal_package_notify)
return;
/* lower threshold check */
if (msr_val & THERM_LOG_THRESHOLD0)
notify_thres_0 = true;
/* higher threshold check */
if (msr_val & THERM_LOG_THRESHOLD1)
notify_thres_1 = true;
if (!notify_thres_0 && !notify_thres_1)
return;
if (platform_thermal_package_rate_control &&
platform_thermal_package_rate_control()) {
/* Rate control is implemented in callback */
platform_thermal_package_notify(msr_val);
return;
}
/* lower threshold reached */
if (notify_thres_0 && thresh_event_valid(PACKAGE_LEVEL, 0))
platform_thermal_package_notify(msr_val);
/* higher threshold reached */
if (notify_thres_1 && thresh_event_valid(PACKAGE_LEVEL, 1))
platform_thermal_package_notify(msr_val);
}
static void notify_thresholds(__u64 msr_val)
{
/* check whether the interrupt handler is defined;
* otherwise simply return
*/
if (!platform_thermal_notify)
return;
/* lower threshold reached */
if ((msr_val & THERM_LOG_THRESHOLD0) &&
thresh_event_valid(CORE_LEVEL, 0))
platform_thermal_notify(msr_val);
/* higher threshold reached */
if ((msr_val & THERM_LOG_THRESHOLD1) &&
thresh_event_valid(CORE_LEVEL, 1))
platform_thermal_notify(msr_val);
}
/* Thermal transition interrupt handler */
void intel_thermal_interrupt(void)
{
__u64 msr_val;
if (static_cpu_has(X86_FEATURE_HWP))
wrmsrl_safe(MSR_HWP_STATUS, 0);
rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
/* Check for violation of core thermal thresholds*/
notify_thresholds(msr_val);
therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
THERMAL_THROTTLING_EVENT,
CORE_LEVEL);
if (this_cpu_has(X86_FEATURE_PLN) && int_pln_enable)
therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
POWER_LIMIT_EVENT,
CORE_LEVEL);
if (this_cpu_has(X86_FEATURE_PTS)) {
rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
/* check violations of package thermal thresholds */
notify_package_thresholds(msr_val);
therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
THERMAL_THROTTLING_EVENT,
PACKAGE_LEVEL);
if (this_cpu_has(X86_FEATURE_PLN) && int_pln_enable)
therm_throt_process(msr_val &
PACKAGE_THERM_STATUS_POWER_LIMIT,
POWER_LIMIT_EVENT,
PACKAGE_LEVEL);
}
}
/* Thermal monitoring depends on APIC, ACPI and clock modulation */
static int intel_thermal_supported(struct cpuinfo_x86 *c)
{
if (!boot_cpu_has(X86_FEATURE_APIC))
return 0;
if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
return 0;
return 1;
}
bool x86_thermal_enabled(void)
{
return atomic_read(&therm_throt_en);
}
void __init therm_lvt_init(void)
{
/*
* This function is only called on boot CPU. Save the init thermal
* LVT value on BSP and use that value to restore APs' thermal LVT
* entry BIOS programmed later
*/
if (intel_thermal_supported(&boot_cpu_data))
lvtthmr_init = apic_read(APIC_LVTTHMR);
}
void intel_init_thermal(struct cpuinfo_x86 *c)
{
unsigned int cpu = smp_processor_id();
int tm2 = 0;
u32 l, h;
if (!intel_thermal_supported(c))
return;
/*
* First check if its enabled already, in which case there might
* be some SMM goo which handles it, so we can't even put a handler
* since it might be delivered via SMI already:
*/
rdmsr(MSR_IA32_MISC_ENABLE, l, h);
h = lvtthmr_init;
/*
* The initial value of thermal LVT entries on all APs always reads
* 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
* sequence to them and LVT registers are reset to 0s except for
* the mask bits which are set to 1s when APs receive INIT IPI.
* If BIOS takes over the thermal interrupt and sets its interrupt
* delivery mode to SMI (not fixed), it restores the value that the
* BIOS has programmed on AP based on BSP's info we saved since BIOS
* is always setting the same value for all threads/cores.
*/
if ((h & APIC_DM_FIXED_MASK) != APIC_DM_FIXED)
apic_write(APIC_LVTTHMR, lvtthmr_init);
if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
if (system_state == SYSTEM_BOOTING)
pr_debug("CPU%d: Thermal monitoring handled by SMI\n", cpu);
return;
}
/* early Pentium M models use different method for enabling TM2 */
if (cpu_has(c, X86_FEATURE_TM2)) {
if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
rdmsr(MSR_THERM2_CTL, l, h);
if (l & MSR_THERM2_CTL_TM_SELECT)
tm2 = 1;
} else if (l & MSR_IA32_MISC_ENABLE_TM2)
tm2 = 1;
}
/* We'll mask the thermal vector in the lapic till we're ready: */
h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
apic_write(APIC_LVTTHMR, h);
rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
if (cpu_has(c, X86_FEATURE_PLN) && !int_pln_enable)
wrmsr(MSR_IA32_THERM_INTERRUPT,
(l | (THERM_INT_LOW_ENABLE
| THERM_INT_HIGH_ENABLE)) & ~THERM_INT_PLN_ENABLE, h);
else if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable)
wrmsr(MSR_IA32_THERM_INTERRUPT,
l | (THERM_INT_LOW_ENABLE
| THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
else
wrmsr(MSR_IA32_THERM_INTERRUPT,
l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
if (cpu_has(c, X86_FEATURE_PTS)) {
rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
if (cpu_has(c, X86_FEATURE_PLN) && !int_pln_enable)
wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
(l | (PACKAGE_THERM_INT_LOW_ENABLE
| PACKAGE_THERM_INT_HIGH_ENABLE))
& ~PACKAGE_THERM_INT_PLN_ENABLE, h);
else if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable)
wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
l | (PACKAGE_THERM_INT_LOW_ENABLE
| PACKAGE_THERM_INT_HIGH_ENABLE
| PACKAGE_THERM_INT_PLN_ENABLE), h);
else
wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
l | (PACKAGE_THERM_INT_LOW_ENABLE
| PACKAGE_THERM_INT_HIGH_ENABLE), h);
}
rdmsr(MSR_IA32_MISC_ENABLE, l, h);
wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
pr_info_once("CPU0: Thermal monitoring enabled (%s)\n",
tm2 ? "TM2" : "TM1");
/* enable thermal throttle processing */
atomic_set(&therm_throt_en, 1);
}