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 #define THERMAL_THROTTLING_EVENT 0
38 #define POWER_LIMIT_EVENT 1
41 * Current thermal event state:
43 struct _thermal_state {
48 unsigned long last_count;
51 struct thermal_state {
52 struct _thermal_state core_throttle;
53 struct _thermal_state core_power_limit;
54 struct _thermal_state package_throttle;
55 struct _thermal_state package_power_limit;
56 struct _thermal_state core_thresh0;
57 struct _thermal_state core_thresh1;
60 /* Callback to handle core threshold interrupts */
61 int (*platform_thermal_notify)(__u64 msr_val);
62 EXPORT_SYMBOL(platform_thermal_notify);
64 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
66 static atomic_t therm_throt_en = ATOMIC_INIT(0);
68 static u32 lvtthmr_init __read_mostly;
71 #define define_therm_throt_sysdev_one_ro(_name) \
72 static SYSDEV_ATTR(_name, 0444, \
73 therm_throt_sysdev_show_##_name, \
76 #define define_therm_throt_sysdev_show_func(event, name) \
78 static ssize_t therm_throt_sysdev_show_##event##_##name( \
79 struct sys_device *dev, \
80 struct sysdev_attribute *attr, \
83 unsigned int cpu = dev->id; \
86 preempt_disable(); /* CPU hotplug */ \
87 if (cpu_online(cpu)) { \
88 ret = sprintf(buf, "%lu\n", \
89 per_cpu(thermal_state, cpu).event.name); \
97 define_therm_throt_sysdev_show_func(core_throttle, count);
98 define_therm_throt_sysdev_one_ro(core_throttle_count);
100 define_therm_throt_sysdev_show_func(core_power_limit, count);
101 define_therm_throt_sysdev_one_ro(core_power_limit_count);
103 define_therm_throt_sysdev_show_func(package_throttle, count);
104 define_therm_throt_sysdev_one_ro(package_throttle_count);
106 define_therm_throt_sysdev_show_func(package_power_limit, count);
107 define_therm_throt_sysdev_one_ro(package_power_limit_count);
109 static struct attribute *thermal_throttle_attrs[] = {
110 &attr_core_throttle_count.attr,
114 static struct attribute_group thermal_attr_group = {
115 .attrs = thermal_throttle_attrs,
116 .name = "thermal_throttle"
118 #endif /* CONFIG_SYSFS */
121 #define PACKAGE_LEVEL 1
124 * therm_throt_process - Process thermal throttling event from interrupt
125 * @curr: Whether the condition is current or not (boolean), since the
126 * thermal interrupt normally gets called both when the thermal
127 * event begins and once the event has ended.
129 * This function is called by the thermal interrupt after the
130 * IRQ has been acknowledged.
132 * It will take care of rate limiting and printing messages to the syslog.
134 * Returns: 0 : Event should NOT be further logged, i.e. still in
135 * "timeout" from previous log message.
136 * 1 : Event should be logged further, and a message has been
137 * printed to the syslog.
139 static int therm_throt_process(bool new_event, int event, int level)
141 struct _thermal_state *state;
142 unsigned int this_cpu = smp_processor_id();
145 struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
147 now = get_jiffies_64();
148 if (level == CORE_LEVEL) {
149 if (event == THERMAL_THROTTLING_EVENT)
150 state = &pstate->core_throttle;
151 else if (event == POWER_LIMIT_EVENT)
152 state = &pstate->core_power_limit;
155 } else if (level == PACKAGE_LEVEL) {
156 if (event == THERMAL_THROTTLING_EVENT)
157 state = &pstate->package_throttle;
158 else if (event == POWER_LIMIT_EVENT)
159 state = &pstate->package_power_limit;
165 old_event = state->new_event;
166 state->new_event = new_event;
171 if (time_before64(now, state->next_check) &&
172 state->count != state->last_count)
175 state->next_check = now + CHECK_INTERVAL;
176 state->last_count = state->count;
178 /* if we just entered the thermal event */
180 if (event == THERMAL_THROTTLING_EVENT)
181 printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
183 level == CORE_LEVEL ? "Core" : "Package",
186 printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu)\n",
188 level == CORE_LEVEL ? "Core" : "Package",
191 add_taint(TAINT_MACHINE_CHECK);
195 if (event == THERMAL_THROTTLING_EVENT)
196 printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
198 level == CORE_LEVEL ? "Core" : "Package");
200 printk(KERN_INFO "CPU%d: %s power limit normal\n",
202 level == CORE_LEVEL ? "Core" : "Package");
209 static int thresh_event_valid(int event)
211 struct _thermal_state *state;
212 unsigned int this_cpu = smp_processor_id();
213 struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
214 u64 now = get_jiffies_64();
216 state = (event == 0) ? &pstate->core_thresh0 : &pstate->core_thresh1;
218 if (time_before64(now, state->next_check))
221 state->next_check = now + CHECK_INTERVAL;
226 /* Add/Remove thermal_throttle interface for CPU device: */
227 static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev,
231 struct cpuinfo_x86 *c = &cpu_data(cpu);
233 err = sysfs_create_group(&sys_dev->kobj, &thermal_attr_group);
237 if (cpu_has(c, X86_FEATURE_PLN))
238 err = sysfs_add_file_to_group(&sys_dev->kobj,
239 &attr_core_power_limit_count.attr,
240 thermal_attr_group.name);
241 if (cpu_has(c, X86_FEATURE_PTS)) {
242 err = sysfs_add_file_to_group(&sys_dev->kobj,
243 &attr_package_throttle_count.attr,
244 thermal_attr_group.name);
245 if (cpu_has(c, X86_FEATURE_PLN))
246 err = sysfs_add_file_to_group(&sys_dev->kobj,
247 &attr_package_power_limit_count.attr,
248 thermal_attr_group.name);
254 static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
256 sysfs_remove_group(&sys_dev->kobj, &thermal_attr_group);
259 /* Mutex protecting device creation against CPU hotplug: */
260 static DEFINE_MUTEX(therm_cpu_lock);
262 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
264 thermal_throttle_cpu_callback(struct notifier_block *nfb,
265 unsigned long action,
268 unsigned int cpu = (unsigned long)hcpu;
269 struct sys_device *sys_dev;
272 sys_dev = get_cpu_sysdev(cpu);
276 case CPU_UP_PREPARE_FROZEN:
277 mutex_lock(&therm_cpu_lock);
278 err = thermal_throttle_add_dev(sys_dev, cpu);
279 mutex_unlock(&therm_cpu_lock);
282 case CPU_UP_CANCELED:
283 case CPU_UP_CANCELED_FROZEN:
285 case CPU_DEAD_FROZEN:
286 mutex_lock(&therm_cpu_lock);
287 thermal_throttle_remove_dev(sys_dev);
288 mutex_unlock(&therm_cpu_lock);
291 return notifier_from_errno(err);
294 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
296 .notifier_call = thermal_throttle_cpu_callback,
299 static __init int thermal_throttle_init_device(void)
301 unsigned int cpu = 0;
304 if (!atomic_read(&therm_throt_en))
307 register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
309 #ifdef CONFIG_HOTPLUG_CPU
310 mutex_lock(&therm_cpu_lock);
312 /* connect live CPUs to sysfs */
313 for_each_online_cpu(cpu) {
314 err = thermal_throttle_add_dev(get_cpu_sysdev(cpu), cpu);
317 #ifdef CONFIG_HOTPLUG_CPU
318 mutex_unlock(&therm_cpu_lock);
323 device_initcall(thermal_throttle_init_device);
325 #endif /* CONFIG_SYSFS */
328 * Set up the most two significant bit to notify mce log that this thermal
330 * This is a temp solution. May be changed in the future with mce log
333 #define CORE_THROTTLED (0)
334 #define CORE_POWER_LIMIT ((__u64)1 << 62)
335 #define PACKAGE_THROTTLED ((__u64)2 << 62)
336 #define PACKAGE_POWER_LIMIT ((__u64)3 << 62)
338 static void notify_thresholds(__u64 msr_val)
340 /* check whether the interrupt handler is defined;
341 * otherwise simply return
343 if (!platform_thermal_notify)
346 /* lower threshold reached */
347 if ((msr_val & THERM_LOG_THRESHOLD0) && thresh_event_valid(0))
348 platform_thermal_notify(msr_val);
349 /* higher threshold reached */
350 if ((msr_val & THERM_LOG_THRESHOLD1) && thresh_event_valid(1))
351 platform_thermal_notify(msr_val);
354 /* Thermal transition interrupt handler */
355 static void intel_thermal_interrupt(void)
358 struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
360 rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
362 /* Check for violation of core thermal thresholds*/
363 notify_thresholds(msr_val);
365 if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
366 THERMAL_THROTTLING_EVENT,
368 mce_log_therm_throt_event(CORE_THROTTLED | msr_val);
370 if (cpu_has(c, X86_FEATURE_PLN))
371 if (therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
374 mce_log_therm_throt_event(CORE_POWER_LIMIT | msr_val);
376 if (cpu_has(c, X86_FEATURE_PTS)) {
377 rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
378 if (therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
379 THERMAL_THROTTLING_EVENT,
381 mce_log_therm_throt_event(PACKAGE_THROTTLED | msr_val);
382 if (cpu_has(c, X86_FEATURE_PLN))
383 if (therm_throt_process(msr_val &
384 PACKAGE_THERM_STATUS_POWER_LIMIT,
387 mce_log_therm_throt_event(PACKAGE_POWER_LIMIT
392 static void unexpected_thermal_interrupt(void)
394 printk(KERN_ERR "CPU%d: Unexpected LVT thermal interrupt!\n",
396 add_taint(TAINT_MACHINE_CHECK);
399 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
401 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
405 inc_irq_stat(irq_thermal_count);
406 smp_thermal_vector();
408 /* Ack only at the end to avoid potential reentry */
412 /* Thermal monitoring depends on APIC, ACPI and clock modulation */
413 static int intel_thermal_supported(struct cpuinfo_x86 *c)
417 if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
422 void __init mcheck_intel_therm_init(void)
425 * This function is only called on boot CPU. Save the init thermal
426 * LVT value on BSP and use that value to restore APs' thermal LVT
427 * entry BIOS programmed later
429 if (intel_thermal_supported(&boot_cpu_data))
430 lvtthmr_init = apic_read(APIC_LVTTHMR);
433 void intel_init_thermal(struct cpuinfo_x86 *c)
435 unsigned int cpu = smp_processor_id();
439 if (!intel_thermal_supported(c))
443 * First check if its enabled already, in which case there might
444 * be some SMM goo which handles it, so we can't even put a handler
445 * since it might be delivered via SMI already:
447 rdmsr(MSR_IA32_MISC_ENABLE, l, h);
450 * The initial value of thermal LVT entries on all APs always reads
451 * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
452 * sequence to them and LVT registers are reset to 0s except for
453 * the mask bits which are set to 1s when APs receive INIT IPI.
454 * Always restore the value that BIOS has programmed on AP based on
455 * BSP's info we saved since BIOS is always setting the same value
456 * for all threads/cores
458 apic_write(APIC_LVTTHMR, lvtthmr_init);
462 if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
464 "CPU%d: Thermal monitoring handled by SMI\n", cpu);
468 /* Check whether a vector already exists */
469 if (h & APIC_VECTOR_MASK) {
471 "CPU%d: Thermal LVT vector (%#x) already installed\n",
472 cpu, (h & APIC_VECTOR_MASK));
476 /* early Pentium M models use different method for enabling TM2 */
477 if (cpu_has(c, X86_FEATURE_TM2)) {
478 if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
479 rdmsr(MSR_THERM2_CTL, l, h);
480 if (l & MSR_THERM2_CTL_TM_SELECT)
482 } else if (l & MSR_IA32_MISC_ENABLE_TM2)
486 /* We'll mask the thermal vector in the lapic till we're ready: */
487 h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
488 apic_write(APIC_LVTTHMR, h);
490 rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
491 if (cpu_has(c, X86_FEATURE_PLN))
492 wrmsr(MSR_IA32_THERM_INTERRUPT,
493 l | (THERM_INT_LOW_ENABLE
494 | THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
496 wrmsr(MSR_IA32_THERM_INTERRUPT,
497 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
499 if (cpu_has(c, X86_FEATURE_PTS)) {
500 rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
501 if (cpu_has(c, X86_FEATURE_PLN))
502 wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
503 l | (PACKAGE_THERM_INT_LOW_ENABLE
504 | PACKAGE_THERM_INT_HIGH_ENABLE
505 | PACKAGE_THERM_INT_PLN_ENABLE), h);
507 wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
508 l | (PACKAGE_THERM_INT_LOW_ENABLE
509 | PACKAGE_THERM_INT_HIGH_ENABLE), h);
512 smp_thermal_vector = intel_thermal_interrupt;
514 rdmsr(MSR_IA32_MISC_ENABLE, l, h);
515 wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
517 /* Unmask the thermal vector: */
518 l = apic_read(APIC_LVTTHMR);
519 apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
521 printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
522 tm2 ? "TM2" : "TM1");
524 /* enable thermal throttle processing */
525 atomic_set(&therm_throt_en, 1);