/*
* 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 and mcelog 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/sysdev.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/apic.h>
#include <asm/idle.h>
#include <asm/mce.h>
#include <asm/msr.h>
/* How long to wait between reporting thermal events */
#define CHECK_INTERVAL (300 * HZ)
/*
* Current thermal throttling state:
*/
struct thermal_state {
bool is_throttled;
u64 next_check;
unsigned long throttle_count;
unsigned long last_throttle_count;
};
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_sysdev_one_ro(_name) \
static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
#define define_therm_throt_sysdev_show_func(name) \
\
static ssize_t therm_throt_sysdev_show_##name( \
struct sys_device *dev, \
struct sysdev_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).name); \
else \
ret = 0; \
preempt_enable(); \
\
return ret; \
}
define_therm_throt_sysdev_show_func(throttle_count);
define_therm_throt_sysdev_one_ro(throttle_count);
static struct attribute *thermal_throttle_attrs[] = {
&attr_throttle_count.attr,
NULL
};
static struct attribute_group thermal_throttle_attr_group = {
.attrs = thermal_throttle_attrs,
.name = "thermal_throttle"
};
#endif /* CONFIG_SYSFS */
/***
* 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.
*
* Returns: 0 : Event should NOT be further logged, i.e. still in
* "timeout" from previous log message.
* 1 : Event should be logged further, and a message has been
* printed to the syslog.
*/
static int therm_throt_process(bool is_throttled)
{
struct thermal_state *state;
unsigned int this_cpu;
bool was_throttled;
u64 now;
this_cpu = smp_processor_id();
now = get_jiffies_64();
state = &per_cpu(thermal_state, this_cpu);
was_throttled = state->is_throttled;
state->is_throttled = is_throttled;
if (is_throttled)
state->throttle_count++;
if (time_before64(now, state->next_check) &&
state->throttle_count != state->last_throttle_count)
return 0;
state->next_check = now + CHECK_INTERVAL;
state->last_throttle_count = state->throttle_count;
/* if we just entered the thermal event */
if (is_throttled) {
printk(KERN_CRIT "CPU%d: Temperature above threshold, cpu clock throttled (total events = %lu)\n", this_cpu, state->throttle_count);
add_taint(TAINT_MACHINE_CHECK);
return 1;
}
if (was_throttled) {
printk(KERN_INFO "CPU%d: Temperature/speed normal\n", this_cpu);
return 1;
}
return 0;
}
#ifdef CONFIG_SYSFS
/* Add/Remove thermal_throttle interface for CPU device: */
static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
{
return sysfs_create_group(&sys_dev->kobj,
&thermal_throttle_attr_group);
}
static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
{
sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
}
/* Mutex protecting device creation against CPU hotplug: */
static DEFINE_MUTEX(therm_cpu_lock);
/* Get notified when a cpu comes on/off. Be hotplug friendly. */
static __cpuinit int
thermal_throttle_cpu_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
struct sys_device *sys_dev;
int err = 0;
sys_dev = get_cpu_sysdev(cpu);
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
mutex_lock(&therm_cpu_lock);
err = thermal_throttle_add_dev(sys_dev);
mutex_unlock(&therm_cpu_lock);
WARN_ON(err);
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
case CPU_DEAD_FROZEN:
mutex_lock(&therm_cpu_lock);
thermal_throttle_remove_dev(sys_dev);
mutex_unlock(&therm_cpu_lock);
break;
}
return notifier_from_errno(err);
}
static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
{
.notifier_call = thermal_throttle_cpu_callback,
};
static __init int thermal_throttle_init_device(void)
{
unsigned int cpu = 0;
int err;
if (!atomic_read(&therm_throt_en))
return 0;
register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
#ifdef CONFIG_HOTPLUG_CPU
mutex_lock(&therm_cpu_lock);
#endif
/* connect live CPUs to sysfs */
for_each_online_cpu(cpu) {
err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
WARN_ON(err);
}
#ifdef CONFIG_HOTPLUG_CPU
mutex_unlock(&therm_cpu_lock);
#endif
return 0;
}
device_initcall(thermal_throttle_init_device);
#endif /* CONFIG_SYSFS */
/* Thermal transition interrupt handler */
static void intel_thermal_interrupt(void)
{
__u64 msr_val;
rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
if (therm_throt_process((msr_val & THERM_STATUS_PROCHOT) != 0))
mce_log_therm_throt_event(msr_val);
}
static void unexpected_thermal_interrupt(void)
{
printk(KERN_ERR "CPU%d: Unexpected LVT TMR interrupt!\n",
smp_processor_id());
add_taint(TAINT_MACHINE_CHECK);
}
static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
{
exit_idle();
irq_enter();
inc_irq_stat(irq_thermal_count);
smp_thermal_vector();
irq_exit();
/* Ack only at the end to avoid potential reentry */
ack_APIC_irq();
}
/* Thermal monitoring depends on APIC, ACPI and clock modulation */
static int intel_thermal_supported(struct cpuinfo_x86 *c)
{
if (!cpu_has_apic)
return 0;
if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
return 0;
return 1;
}
void __init mcheck_intel_therm_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);
/*
* 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.
* Always restore the value that BIOS has programmed on AP based on
* BSP's info we saved since BIOS is always setting the same value
* for all threads/cores
*/
apic_write(APIC_LVTTHMR, lvtthmr_init);
h = lvtthmr_init;
if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
printk(KERN_DEBUG
"CPU%d: Thermal monitoring handled by SMI\n", cpu);
return;
}
/* Check whether a vector already exists */
if (h & APIC_VECTOR_MASK) {
printk(KERN_DEBUG
"CPU%d: Thermal LVT vector (%#x) already installed\n",
cpu, (h & APIC_VECTOR_MASK));
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);
wrmsr(MSR_IA32_THERM_INTERRUPT,
l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
smp_thermal_vector = intel_thermal_interrupt;
rdmsr(MSR_IA32_MISC_ENABLE, l, h);
wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
/* Unmask the thermal vector: */
l = apic_read(APIC_LVTTHMR);
apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
tm2 ? "TM2" : "TM1");
/* enable thermal throttle processing */
atomic_set(&therm_throt_en, 1);
}
