1 /*
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).
4 *
5 * This allows consistent reporting of CPU thermal throttle events.
6 *
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).
10 *
11 * Author: Dmitriy Zavin (dmitriyz@google.com)
12 *
13 * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c.
14 * Inspired by Ross Biro's and Al Borchers' counter code.
15 */
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/export.h>
22 #include <linux/types.h>
23 #include <linux/init.h>
24 #include <linux/smp.h>
25 #include <linux/cpu.h>
26
27 #include <asm/processor.h>
28 #include <asm/system.h>
29 #include <asm/apic.h>
30 #include <asm/idle.h>
31 #include <asm/mce.h>
32 #include <asm/msr.h>
33
34 /* How long to wait between reporting thermal events */
35 #define CHECK_INTERVAL (300 * HZ)
36
37 #define THERMAL_THROTTLING_EVENT 0
38 #define POWER_LIMIT_EVENT 1
39
40 /*
41 * Current thermal event state:
42 */
43 struct _thermal_state {
44 bool new_event;
45 int event;
46 u64 next_check;
47 unsigned long count;
48 unsigned long last_count;
49 };
50
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;
58 };
59
60 /* Callback to handle core threshold interrupts */
61 int (*platform_thermal_notify)(__u64 msr_val);
62 EXPORT_SYMBOL(platform_thermal_notify);
63
64 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
65
66 static atomic_t therm_throt_en = ATOMIC_INIT(0);
67
68 static u32 lvtthmr_init __read_mostly;
69
70 #ifdef CONFIG_SYSFS
71 #define define_therm_throt_device_one_ro(_name) \
72 static DEVICE_ATTR(_name, 0444, \
73 therm_throt_device_show_##_name, \
74 NULL) \
75
76 #define define_therm_throt_device_show_func(event, name) \
77 \
78 static ssize_t therm_throt_device_show_##event##_##name( \
79 struct device *dev, \
80 struct device_attribute *attr, \
81 char *buf) \
82 { \
83 unsigned int cpu = dev->id; \
84 ssize_t ret; \
85 \
86 preempt_disable(); /* CPU hotplug */ \
87 if (cpu_online(cpu)) { \
88 ret = sprintf(buf, "%lu\n", \
89 per_cpu(thermal_state, cpu).event.name); \
90 } else \
91 ret = 0; \
92 preempt_enable(); \
93 \
94 return ret; \
95 }
96
97 define_therm_throt_device_show_func(core_throttle, count);
98 define_therm_throt_device_one_ro(core_throttle_count);
99
100 define_therm_throt_device_show_func(core_power_limit, count);
101 define_therm_throt_device_one_ro(core_power_limit_count);
102
103 define_therm_throt_device_show_func(package_throttle, count);
104 define_therm_throt_device_one_ro(package_throttle_count);
105
106 define_therm_throt_device_show_func(package_power_limit, count);
107 define_therm_throt_device_one_ro(package_power_limit_count);
108
109 static struct attribute *thermal_throttle_attrs[] = {
110 &dev_attr_core_throttle_count.attr,
111 NULL
112 };
113
114 static struct attribute_group thermal_attr_group = {
115 .attrs = thermal_throttle_attrs,
116 .name = "thermal_throttle"
117 };
118 #endif /* CONFIG_SYSFS */
119
120 #define CORE_LEVEL 0
121 #define PACKAGE_LEVEL 1
122
123 /***
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.
128 *
129 * This function is called by the thermal interrupt after the
130 * IRQ has been acknowledged.
131 *
132 * It will take care of rate limiting and printing messages to the syslog.
133 *
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.
138 */
therm_throt_process(bool new_event,int event,int level)139 static int therm_throt_process(bool new_event, int event, int level)
140 {
141 struct _thermal_state *state;
142 unsigned int this_cpu = smp_processor_id();
143 bool old_event;
144 u64 now;
145 struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
146
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;
153 else
154 return 0;
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;
160 else
161 return 0;
162 } else
163 return 0;
164
165 old_event = state->new_event;
166 state->new_event = new_event;
167
168 if (new_event)
169 state->count++;
170
171 if (time_before64(now, state->next_check) &&
172 state->count != state->last_count)
173 return 0;
174
175 state->next_check = now + CHECK_INTERVAL;
176 state->last_count = state->count;
177
178 /* if we just entered the thermal event */
179 if (new_event) {
180 if (event == THERMAL_THROTTLING_EVENT)
181 printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
182 this_cpu,
183 level == CORE_LEVEL ? "Core" : "Package",
184 state->count);
185 else
186 printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu)\n",
187 this_cpu,
188 level == CORE_LEVEL ? "Core" : "Package",
189 state->count);
190 return 1;
191 }
192 if (old_event) {
193 if (event == THERMAL_THROTTLING_EVENT)
194 printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
195 this_cpu,
196 level == CORE_LEVEL ? "Core" : "Package");
197 else
198 printk(KERN_INFO "CPU%d: %s power limit normal\n",
199 this_cpu,
200 level == CORE_LEVEL ? "Core" : "Package");
201 return 1;
202 }
203
204 return 0;
205 }
206
thresh_event_valid(int event)207 static int thresh_event_valid(int event)
208 {
209 struct _thermal_state *state;
210 unsigned int this_cpu = smp_processor_id();
211 struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
212 u64 now = get_jiffies_64();
213
214 state = (event == 0) ? &pstate->core_thresh0 : &pstate->core_thresh1;
215
216 if (time_before64(now, state->next_check))
217 return 0;
218
219 state->next_check = now + CHECK_INTERVAL;
220 return 1;
221 }
222
223 #ifdef CONFIG_SYSFS
224 /* Add/Remove thermal_throttle interface for CPU device: */
thermal_throttle_add_dev(struct device * dev,unsigned int cpu)225 static __cpuinit int thermal_throttle_add_dev(struct device *dev,
226 unsigned int cpu)
227 {
228 int err;
229 struct cpuinfo_x86 *c = &cpu_data(cpu);
230
231 err = sysfs_create_group(&dev->kobj, &thermal_attr_group);
232 if (err)
233 return err;
234
235 if (cpu_has(c, X86_FEATURE_PLN))
236 err = sysfs_add_file_to_group(&dev->kobj,
237 &dev_attr_core_power_limit_count.attr,
238 thermal_attr_group.name);
239 if (cpu_has(c, X86_FEATURE_PTS)) {
240 err = sysfs_add_file_to_group(&dev->kobj,
241 &dev_attr_package_throttle_count.attr,
242 thermal_attr_group.name);
243 if (cpu_has(c, X86_FEATURE_PLN))
244 err = sysfs_add_file_to_group(&dev->kobj,
245 &dev_attr_package_power_limit_count.attr,
246 thermal_attr_group.name);
247 }
248
249 return err;
250 }
251
thermal_throttle_remove_dev(struct device * dev)252 static __cpuinit void thermal_throttle_remove_dev(struct device *dev)
253 {
254 sysfs_remove_group(&dev->kobj, &thermal_attr_group);
255 }
256
257 /* Mutex protecting device creation against CPU hotplug: */
258 static DEFINE_MUTEX(therm_cpu_lock);
259
260 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
261 static __cpuinit int
thermal_throttle_cpu_callback(struct notifier_block * nfb,unsigned long action,void * hcpu)262 thermal_throttle_cpu_callback(struct notifier_block *nfb,
263 unsigned long action,
264 void *hcpu)
265 {
266 unsigned int cpu = (unsigned long)hcpu;
267 struct device *dev;
268 int err = 0;
269
270 dev = get_cpu_device(cpu);
271
272 switch (action) {
273 case CPU_UP_PREPARE:
274 case CPU_UP_PREPARE_FROZEN:
275 mutex_lock(&therm_cpu_lock);
276 err = thermal_throttle_add_dev(dev, cpu);
277 mutex_unlock(&therm_cpu_lock);
278 WARN_ON(err);
279 break;
280 case CPU_UP_CANCELED:
281 case CPU_UP_CANCELED_FROZEN:
282 case CPU_DEAD:
283 case CPU_DEAD_FROZEN:
284 mutex_lock(&therm_cpu_lock);
285 thermal_throttle_remove_dev(dev);
286 mutex_unlock(&therm_cpu_lock);
287 break;
288 }
289 return notifier_from_errno(err);
290 }
291
292 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
293 {
294 .notifier_call = thermal_throttle_cpu_callback,
295 };
296
thermal_throttle_init_device(void)297 static __init int thermal_throttle_init_device(void)
298 {
299 unsigned int cpu = 0;
300 int err;
301
302 if (!atomic_read(&therm_throt_en))
303 return 0;
304
305 register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
306
307 #ifdef CONFIG_HOTPLUG_CPU
308 mutex_lock(&therm_cpu_lock);
309 #endif
310 /* connect live CPUs to sysfs */
311 for_each_online_cpu(cpu) {
312 err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
313 WARN_ON(err);
314 }
315 #ifdef CONFIG_HOTPLUG_CPU
316 mutex_unlock(&therm_cpu_lock);
317 #endif
318
319 return 0;
320 }
321 device_initcall(thermal_throttle_init_device);
322
323 #endif /* CONFIG_SYSFS */
324
notify_thresholds(__u64 msr_val)325 static void notify_thresholds(__u64 msr_val)
326 {
327 /* check whether the interrupt handler is defined;
328 * otherwise simply return
329 */
330 if (!platform_thermal_notify)
331 return;
332
333 /* lower threshold reached */
334 if ((msr_val & THERM_LOG_THRESHOLD0) && thresh_event_valid(0))
335 platform_thermal_notify(msr_val);
336 /* higher threshold reached */
337 if ((msr_val & THERM_LOG_THRESHOLD1) && thresh_event_valid(1))
338 platform_thermal_notify(msr_val);
339 }
340
341 /* Thermal transition interrupt handler */
intel_thermal_interrupt(void)342 static void intel_thermal_interrupt(void)
343 {
344 __u64 msr_val;
345
346 rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
347
348 /* Check for violation of core thermal thresholds*/
349 notify_thresholds(msr_val);
350
351 if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
352 THERMAL_THROTTLING_EVENT,
353 CORE_LEVEL) != 0)
354 mce_log_therm_throt_event(msr_val);
355
356 if (this_cpu_has(X86_FEATURE_PLN))
357 therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
358 POWER_LIMIT_EVENT,
359 CORE_LEVEL);
360
361 if (this_cpu_has(X86_FEATURE_PTS)) {
362 rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
363 therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
364 THERMAL_THROTTLING_EVENT,
365 PACKAGE_LEVEL);
366 if (this_cpu_has(X86_FEATURE_PLN))
367 therm_throt_process(msr_val &
368 PACKAGE_THERM_STATUS_POWER_LIMIT,
369 POWER_LIMIT_EVENT,
370 PACKAGE_LEVEL);
371 }
372 }
373
unexpected_thermal_interrupt(void)374 static void unexpected_thermal_interrupt(void)
375 {
376 printk(KERN_ERR "CPU%d: Unexpected LVT thermal interrupt!\n",
377 smp_processor_id());
378 }
379
380 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
381
smp_thermal_interrupt(struct pt_regs * regs)382 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
383 {
384 irq_enter();
385 exit_idle();
386 inc_irq_stat(irq_thermal_count);
387 smp_thermal_vector();
388 irq_exit();
389 /* Ack only at the end to avoid potential reentry */
390 ack_APIC_irq();
391 }
392
393 /* Thermal monitoring depends on APIC, ACPI and clock modulation */
intel_thermal_supported(struct cpuinfo_x86 * c)394 static int intel_thermal_supported(struct cpuinfo_x86 *c)
395 {
396 if (!cpu_has_apic)
397 return 0;
398 if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
399 return 0;
400 return 1;
401 }
402
mcheck_intel_therm_init(void)403 void __init mcheck_intel_therm_init(void)
404 {
405 /*
406 * This function is only called on boot CPU. Save the init thermal
407 * LVT value on BSP and use that value to restore APs' thermal LVT
408 * entry BIOS programmed later
409 */
410 if (intel_thermal_supported(&boot_cpu_data))
411 lvtthmr_init = apic_read(APIC_LVTTHMR);
412 }
413
intel_init_thermal(struct cpuinfo_x86 * c)414 void intel_init_thermal(struct cpuinfo_x86 *c)
415 {
416 unsigned int cpu = smp_processor_id();
417 int tm2 = 0;
418 u32 l, h;
419
420 if (!intel_thermal_supported(c))
421 return;
422
423 /*
424 * First check if its enabled already, in which case there might
425 * be some SMM goo which handles it, so we can't even put a handler
426 * since it might be delivered via SMI already:
427 */
428 rdmsr(MSR_IA32_MISC_ENABLE, l, h);
429
430 h = lvtthmr_init;
431 /*
432 * The initial value of thermal LVT entries on all APs always reads
433 * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
434 * sequence to them and LVT registers are reset to 0s except for
435 * the mask bits which are set to 1s when APs receive INIT IPI.
436 * If BIOS takes over the thermal interrupt and sets its interrupt
437 * delivery mode to SMI (not fixed), it restores the value that the
438 * BIOS has programmed on AP based on BSP's info we saved since BIOS
439 * is always setting the same value for all threads/cores.
440 */
441 if ((h & APIC_DM_FIXED_MASK) != APIC_DM_FIXED)
442 apic_write(APIC_LVTTHMR, lvtthmr_init);
443
444
445 if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
446 printk(KERN_DEBUG
447 "CPU%d: Thermal monitoring handled by SMI\n", cpu);
448 return;
449 }
450
451 /* Check whether a vector already exists */
452 if (h & APIC_VECTOR_MASK) {
453 printk(KERN_DEBUG
454 "CPU%d: Thermal LVT vector (%#x) already installed\n",
455 cpu, (h & APIC_VECTOR_MASK));
456 return;
457 }
458
459 /* early Pentium M models use different method for enabling TM2 */
460 if (cpu_has(c, X86_FEATURE_TM2)) {
461 if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
462 rdmsr(MSR_THERM2_CTL, l, h);
463 if (l & MSR_THERM2_CTL_TM_SELECT)
464 tm2 = 1;
465 } else if (l & MSR_IA32_MISC_ENABLE_TM2)
466 tm2 = 1;
467 }
468
469 /* We'll mask the thermal vector in the lapic till we're ready: */
470 h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
471 apic_write(APIC_LVTTHMR, h);
472
473 rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
474 if (cpu_has(c, X86_FEATURE_PLN))
475 wrmsr(MSR_IA32_THERM_INTERRUPT,
476 l | (THERM_INT_LOW_ENABLE
477 | THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
478 else
479 wrmsr(MSR_IA32_THERM_INTERRUPT,
480 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
481
482 if (cpu_has(c, X86_FEATURE_PTS)) {
483 rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
484 if (cpu_has(c, X86_FEATURE_PLN))
485 wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
486 l | (PACKAGE_THERM_INT_LOW_ENABLE
487 | PACKAGE_THERM_INT_HIGH_ENABLE
488 | PACKAGE_THERM_INT_PLN_ENABLE), h);
489 else
490 wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
491 l | (PACKAGE_THERM_INT_LOW_ENABLE
492 | PACKAGE_THERM_INT_HIGH_ENABLE), h);
493 }
494
495 smp_thermal_vector = intel_thermal_interrupt;
496
497 rdmsr(MSR_IA32_MISC_ENABLE, l, h);
498 wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
499
500 /* Unmask the thermal vector: */
501 l = apic_read(APIC_LVTTHMR);
502 apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
503
504 printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
505 tm2 ? "TM2" : "TM1");
506
507 /* enable thermal throttle processing */
508 atomic_set(&therm_throt_en, 1);
509 }
510