2 * Thermal throttle event support code (such as syslog messaging and rate
3 * limiting) that was factored out from x86_64 (mce_intel.c) and i386 (p4.c).
5 * This allows consistent reporting of CPU thermal throttle events.
7 * Maintains a counter in /sys that keeps track of the number of thermal
8 * events, such that the user knows how bad the thermal problem might be
9 * (since the logging to syslog and mcelog is rate limited).
11 * Author: Dmitriy Zavin (dmitriyz@google.com)
13 * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c.
14 * Inspired by Ross Biro's and Al Borchers' counter code.
16 #include <linux/interrupt.h>
17 #include <linux/notifier.h>
18 #include <linux/jiffies.h>
19 #include <linux/kernel.h>
20 #include <linux/percpu.h>
21 #include <linux/sysdev.h>
22 #include <linux/types.h>
23 #include <linux/init.h>
24 #include <linux/smp.h>
25 #include <linux/cpu.h>
27 #include <asm/processor.h>
28 #include <asm/system.h>
34 /* How long to wait between reporting thermal events */
35 #define CHECK_INTERVAL (300 * HZ)
37 static DEFINE_PER_CPU(__u64
, next_check
) = INITIAL_JIFFIES
;
38 static DEFINE_PER_CPU(unsigned long, thermal_throttle_count
);
40 static atomic_t therm_throt_en
= ATOMIC_INIT(0);
43 #define define_therm_throt_sysdev_one_ro(_name) \
44 static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
46 #define define_therm_throt_sysdev_show_func(name) \
47 static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev, \
48 struct sysdev_attribute *attr, \
51 unsigned int cpu = dev->id; \
54 preempt_disable(); /* CPU hotplug */ \
55 if (cpu_online(cpu)) \
56 ret = sprintf(buf, "%lu\n", \
57 per_cpu(thermal_throttle_##name, cpu)); \
65 define_therm_throt_sysdev_show_func(count
);
66 define_therm_throt_sysdev_one_ro(count
);
68 static struct attribute
*thermal_throttle_attrs
[] = {
73 static struct attribute_group thermal_throttle_attr_group
= {
74 .attrs
= thermal_throttle_attrs
,
75 .name
= "thermal_throttle"
77 #endif /* CONFIG_SYSFS */
80 * therm_throt_process - Process thermal throttling event from interrupt
81 * @curr: Whether the condition is current or not (boolean), since the
82 * thermal interrupt normally gets called both when the thermal
83 * event begins and once the event has ended.
85 * This function is called by the thermal interrupt after the
86 * IRQ has been acknowledged.
88 * It will take care of rate limiting and printing messages to the syslog.
90 * Returns: 0 : Event should NOT be further logged, i.e. still in
91 * "timeout" from previous log message.
92 * 1 : Event should be logged further, and a message has been
93 * printed to the syslog.
95 static int therm_throt_process(int curr
)
97 unsigned int cpu
= smp_processor_id();
98 __u64 tmp_jiffs
= get_jiffies_64();
101 __get_cpu_var(thermal_throttle_count
)++;
103 if (time_before64(tmp_jiffs
, __get_cpu_var(next_check
)))
106 __get_cpu_var(next_check
) = tmp_jiffs
+ CHECK_INTERVAL
;
108 /* if we just entered the thermal event */
110 printk(KERN_CRIT
"CPU%d: Temperature above threshold, "
111 "cpu clock throttled (total events = %lu)\n", cpu
,
112 __get_cpu_var(thermal_throttle_count
));
114 add_taint(TAINT_MACHINE_CHECK
);
116 printk(KERN_CRIT
"CPU%d: Temperature/speed normal\n", cpu
);
123 /* Add/Remove thermal_throttle interface for CPU device: */
124 static __cpuinit
int thermal_throttle_add_dev(struct sys_device
*sys_dev
)
126 return sysfs_create_group(&sys_dev
->kobj
,
127 &thermal_throttle_attr_group
);
130 static __cpuinit
void thermal_throttle_remove_dev(struct sys_device
*sys_dev
)
132 sysfs_remove_group(&sys_dev
->kobj
, &thermal_throttle_attr_group
);
135 /* Mutex protecting device creation against CPU hotplug: */
136 static DEFINE_MUTEX(therm_cpu_lock
);
138 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
140 thermal_throttle_cpu_callback(struct notifier_block
*nfb
,
141 unsigned long action
,
144 unsigned int cpu
= (unsigned long)hcpu
;
145 struct sys_device
*sys_dev
;
148 sys_dev
= get_cpu_sysdev(cpu
);
152 case CPU_UP_PREPARE_FROZEN
:
153 mutex_lock(&therm_cpu_lock
);
154 err
= thermal_throttle_add_dev(sys_dev
);
155 mutex_unlock(&therm_cpu_lock
);
158 case CPU_UP_CANCELED
:
159 case CPU_UP_CANCELED_FROZEN
:
161 case CPU_DEAD_FROZEN
:
162 mutex_lock(&therm_cpu_lock
);
163 thermal_throttle_remove_dev(sys_dev
);
164 mutex_unlock(&therm_cpu_lock
);
167 return err
? NOTIFY_BAD
: NOTIFY_OK
;
170 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata
=
172 .notifier_call
= thermal_throttle_cpu_callback
,
175 static __init
int thermal_throttle_init_device(void)
177 unsigned int cpu
= 0;
180 if (!atomic_read(&therm_throt_en
))
183 register_hotcpu_notifier(&thermal_throttle_cpu_notifier
);
185 #ifdef CONFIG_HOTPLUG_CPU
186 mutex_lock(&therm_cpu_lock
);
188 /* connect live CPUs to sysfs */
189 for_each_online_cpu(cpu
) {
190 err
= thermal_throttle_add_dev(get_cpu_sysdev(cpu
));
193 #ifdef CONFIG_HOTPLUG_CPU
194 mutex_unlock(&therm_cpu_lock
);
199 device_initcall(thermal_throttle_init_device
);
201 #endif /* CONFIG_SYSFS */
203 /* Thermal transition interrupt handler */
204 static void intel_thermal_interrupt(void)
208 rdmsrl(MSR_IA32_THERM_STATUS
, msr_val
);
209 if (therm_throt_process(msr_val
& THERM_STATUS_PROCHOT
))
210 mce_log_therm_throt_event(msr_val
);
213 static void unexpected_thermal_interrupt(void)
215 printk(KERN_ERR
"CPU%d: Unexpected LVT TMR interrupt!\n",
217 add_taint(TAINT_MACHINE_CHECK
);
220 static void (*smp_thermal_vector
)(void) = unexpected_thermal_interrupt
;
222 asmlinkage
void smp_thermal_interrupt(struct pt_regs
*regs
)
226 inc_irq_stat(irq_thermal_count
);
227 smp_thermal_vector();
229 /* Ack only at the end to avoid potential reentry */
233 void intel_init_thermal(struct cpuinfo_x86
*c
)
235 unsigned int cpu
= smp_processor_id();
239 /* Thermal monitoring depends on ACPI and clock modulation*/
240 if (!cpu_has(c
, X86_FEATURE_ACPI
) || !cpu_has(c
, X86_FEATURE_ACC
))
244 * First check if its enabled already, in which case there might
245 * be some SMM goo which handles it, so we can't even put a handler
246 * since it might be delivered via SMI already:
248 rdmsr(MSR_IA32_MISC_ENABLE
, l
, h
);
249 h
= apic_read(APIC_LVTTHMR
);
250 if ((l
& MSR_IA32_MISC_ENABLE_TM1
) && (h
& APIC_DM_SMI
)) {
252 "CPU%d: Thermal monitoring handled by SMI\n", cpu
);
256 if (cpu_has(c
, X86_FEATURE_TM2
) && (l
& MSR_IA32_MISC_ENABLE_TM2
))
259 /* Check whether a vector already exists */
260 if (h
& APIC_VECTOR_MASK
) {
262 "CPU%d: Thermal LVT vector (%#x) already installed\n",
263 cpu
, (h
& APIC_VECTOR_MASK
));
267 /* We'll mask the thermal vector in the lapic till we're ready: */
268 h
= THERMAL_APIC_VECTOR
| APIC_DM_FIXED
| APIC_LVT_MASKED
;
269 apic_write(APIC_LVTTHMR
, h
);
271 rdmsr(MSR_IA32_THERM_INTERRUPT
, l
, h
);
272 wrmsr(MSR_IA32_THERM_INTERRUPT
,
273 l
| (THERM_INT_LOW_ENABLE
| THERM_INT_HIGH_ENABLE
), h
);
275 smp_thermal_vector
= intel_thermal_interrupt
;
277 rdmsr(MSR_IA32_MISC_ENABLE
, l
, h
);
278 wrmsr(MSR_IA32_MISC_ENABLE
, l
| MSR_IA32_MISC_ENABLE_TM1
, h
);
280 /* Unmask the thermal vector: */
281 l
= apic_read(APIC_LVTTHMR
);
282 apic_write(APIC_LVTTHMR
, l
& ~APIC_LVT_MASKED
);
284 printk(KERN_INFO
"CPU%d: Thermal monitoring enabled (%s)\n",
285 cpu
, tm2
? "TM2" : "TM1");
287 /* enable thermal throttle processing */
288 atomic_set(&therm_throt_en
, 1);