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Linux/arch/x86/kernel/cpu/mcheck/therm_throt.c

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  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/apic.h>
 29 #include <asm/idle.h>
 30 #include <asm/mce.h>
 31 #include <asm/msr.h>
 32 
 33 /* How long to wait between reporting thermal events */
 34 #define CHECK_INTERVAL          (300 * HZ)
 35 
 36 #define THERMAL_THROTTLING_EVENT        0
 37 #define POWER_LIMIT_EVENT               1
 38 
 39 /*
 40  * Current thermal event state:
 41  */
 42 struct _thermal_state {
 43         bool                    new_event;
 44         int                     event;
 45         u64                     next_check;
 46         unsigned long           count;
 47         unsigned long           last_count;
 48 };
 49 
 50 struct thermal_state {
 51         struct _thermal_state core_throttle;
 52         struct _thermal_state core_power_limit;
 53         struct _thermal_state package_throttle;
 54         struct _thermal_state package_power_limit;
 55         struct _thermal_state core_thresh0;
 56         struct _thermal_state core_thresh1;
 57 };
 58 
 59 /* Callback to handle core threshold interrupts */
 60 int (*platform_thermal_notify)(__u64 msr_val);
 61 EXPORT_SYMBOL(platform_thermal_notify);
 62 
 63 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
 64 
 65 static atomic_t therm_throt_en  = ATOMIC_INIT(0);
 66 
 67 static u32 lvtthmr_init __read_mostly;
 68 
 69 #ifdef CONFIG_SYSFS
 70 #define define_therm_throt_device_one_ro(_name)                         \
 71         static DEVICE_ATTR(_name, 0444,                                 \
 72                            therm_throt_device_show_##_name,             \
 73                                    NULL)                                \
 74 
 75 #define define_therm_throt_device_show_func(event, name)                \
 76                                                                         \
 77 static ssize_t therm_throt_device_show_##event##_##name(                \
 78                         struct device *dev,                             \
 79                         struct device_attribute *attr,                  \
 80                         char *buf)                                      \
 81 {                                                                       \
 82         unsigned int cpu = dev->id;                                     \
 83         ssize_t ret;                                                    \
 84                                                                         \
 85         preempt_disable();      /* CPU hotplug */                       \
 86         if (cpu_online(cpu)) {                                          \
 87                 ret = sprintf(buf, "%lu\n",                             \
 88                               per_cpu(thermal_state, cpu).event.name);  \
 89         } else                                                          \
 90                 ret = 0;                                                \
 91         preempt_enable();                                               \
 92                                                                         \
 93         return ret;                                                     \
 94 }
 95 
 96 define_therm_throt_device_show_func(core_throttle, count);
 97 define_therm_throt_device_one_ro(core_throttle_count);
 98 
 99 define_therm_throt_device_show_func(core_power_limit, count);
100 define_therm_throt_device_one_ro(core_power_limit_count);
101 
102 define_therm_throt_device_show_func(package_throttle, count);
103 define_therm_throt_device_one_ro(package_throttle_count);
104 
105 define_therm_throt_device_show_func(package_power_limit, count);
106 define_therm_throt_device_one_ro(package_power_limit_count);
107 
108 static struct attribute *thermal_throttle_attrs[] = {
109         &dev_attr_core_throttle_count.attr,
110         NULL
111 };
112 
113 static struct attribute_group thermal_attr_group = {
114         .attrs  = thermal_throttle_attrs,
115         .name   = "thermal_throttle"
116 };
117 #endif /* CONFIG_SYSFS */
118 
119 #define CORE_LEVEL      0
120 #define PACKAGE_LEVEL   1
121 
122 /***
123  * therm_throt_process - Process thermal throttling event from interrupt
124  * @curr: Whether the condition is current or not (boolean), since the
125  *        thermal interrupt normally gets called both when the thermal
126  *        event begins and once the event has ended.
127  *
128  * This function is called by the thermal interrupt after the
129  * IRQ has been acknowledged.
130  *
131  * It will take care of rate limiting and printing messages to the syslog.
132  *
133  * Returns: 0 : Event should NOT be further logged, i.e. still in
134  *              "timeout" from previous log message.
135  *          1 : Event should be logged further, and a message has been
136  *              printed to the syslog.
137  */
138 static int therm_throt_process(bool new_event, int event, int level)
139 {
140         struct _thermal_state *state;
141         unsigned int this_cpu = smp_processor_id();
142         bool old_event;
143         u64 now;
144         struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
145 
146         now = get_jiffies_64();
147         if (level == CORE_LEVEL) {
148                 if (event == THERMAL_THROTTLING_EVENT)
149                         state = &pstate->core_throttle;
150                 else if (event == POWER_LIMIT_EVENT)
151                         state = &pstate->core_power_limit;
152                 else
153                          return 0;
154         } else if (level == PACKAGE_LEVEL) {
155                 if (event == THERMAL_THROTTLING_EVENT)
156                         state = &pstate->package_throttle;
157                 else if (event == POWER_LIMIT_EVENT)
158                         state = &pstate->package_power_limit;
159                 else
160                         return 0;
161         } else
162                 return 0;
163 
164         old_event = state->new_event;
165         state->new_event = new_event;
166 
167         if (new_event)
168                 state->count++;
169 
170         if (time_before64(now, state->next_check) &&
171                         state->count != state->last_count)
172                 return 0;
173 
174         state->next_check = now + CHECK_INTERVAL;
175         state->last_count = state->count;
176 
177         /* if we just entered the thermal event */
178         if (new_event) {
179                 if (event == THERMAL_THROTTLING_EVENT)
180                         printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
181                                 this_cpu,
182                                 level == CORE_LEVEL ? "Core" : "Package",
183                                 state->count);
184                 else
185                         printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu)\n",
186                                 this_cpu,
187                                 level == CORE_LEVEL ? "Core" : "Package",
188                                 state->count);
189                 return 1;
190         }
191         if (old_event) {
192                 if (event == THERMAL_THROTTLING_EVENT)
193                         printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
194                                 this_cpu,
195                                 level == CORE_LEVEL ? "Core" : "Package");
196                 else
197                         printk(KERN_INFO "CPU%d: %s power limit normal\n",
198                                 this_cpu,
199                                 level == CORE_LEVEL ? "Core" : "Package");
200                 return 1;
201         }
202 
203         return 0;
204 }
205 
206 static int thresh_event_valid(int event)
207 {
208         struct _thermal_state *state;
209         unsigned int this_cpu = smp_processor_id();
210         struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
211         u64 now = get_jiffies_64();
212 
213         state = (event == 0) ? &pstate->core_thresh0 : &pstate->core_thresh1;
214 
215         if (time_before64(now, state->next_check))
216                 return 0;
217 
218         state->next_check = now + CHECK_INTERVAL;
219         return 1;
220 }
221 
222 #ifdef CONFIG_SYSFS
223 /* Add/Remove thermal_throttle interface for CPU device: */
224 static __cpuinit int thermal_throttle_add_dev(struct device *dev,
225                                 unsigned int cpu)
226 {
227         int err;
228         struct cpuinfo_x86 *c = &cpu_data(cpu);
229 
230         err = sysfs_create_group(&dev->kobj, &thermal_attr_group);
231         if (err)
232                 return err;
233 
234         if (cpu_has(c, X86_FEATURE_PLN))
235                 err = sysfs_add_file_to_group(&dev->kobj,
236                                               &dev_attr_core_power_limit_count.attr,
237                                               thermal_attr_group.name);
238         if (cpu_has(c, X86_FEATURE_PTS)) {
239                 err = sysfs_add_file_to_group(&dev->kobj,
240                                               &dev_attr_package_throttle_count.attr,
241                                               thermal_attr_group.name);
242                 if (cpu_has(c, X86_FEATURE_PLN))
243                         err = sysfs_add_file_to_group(&dev->kobj,
244                                         &dev_attr_package_power_limit_count.attr,
245                                         thermal_attr_group.name);
246         }
247 
248         return err;
249 }
250 
251 static __cpuinit void thermal_throttle_remove_dev(struct device *dev)
252 {
253         sysfs_remove_group(&dev->kobj, &thermal_attr_group);
254 }
255 
256 /* Mutex protecting device creation against CPU hotplug: */
257 static DEFINE_MUTEX(therm_cpu_lock);
258 
259 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
260 static __cpuinit int
261 thermal_throttle_cpu_callback(struct notifier_block *nfb,
262                               unsigned long action,
263                               void *hcpu)
264 {
265         unsigned int cpu = (unsigned long)hcpu;
266         struct device *dev;
267         int err = 0;
268 
269         dev = get_cpu_device(cpu);
270 
271         switch (action) {
272         case CPU_UP_PREPARE:
273         case CPU_UP_PREPARE_FROZEN:
274                 mutex_lock(&therm_cpu_lock);
275                 err = thermal_throttle_add_dev(dev, cpu);
276                 mutex_unlock(&therm_cpu_lock);
277                 WARN_ON(err);
278                 break;
279         case CPU_UP_CANCELED:
280         case CPU_UP_CANCELED_FROZEN:
281         case CPU_DEAD:
282         case CPU_DEAD_FROZEN:
283                 mutex_lock(&therm_cpu_lock);
284                 thermal_throttle_remove_dev(dev);
285                 mutex_unlock(&therm_cpu_lock);
286                 break;
287         }
288         return notifier_from_errno(err);
289 }
290 
291 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
292 {
293         .notifier_call = thermal_throttle_cpu_callback,
294 };
295 
296 static __init int thermal_throttle_init_device(void)
297 {
298         unsigned int cpu = 0;
299         int err;
300 
301         if (!atomic_read(&therm_throt_en))
302                 return 0;
303 
304         register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
305 
306 #ifdef CONFIG_HOTPLUG_CPU
307         mutex_lock(&therm_cpu_lock);
308 #endif
309         /* connect live CPUs to sysfs */
310         for_each_online_cpu(cpu) {
311                 err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
312                 WARN_ON(err);
313         }
314 #ifdef CONFIG_HOTPLUG_CPU
315         mutex_unlock(&therm_cpu_lock);
316 #endif
317 
318         return 0;
319 }
320 device_initcall(thermal_throttle_init_device);
321 
322 #endif /* CONFIG_SYSFS */
323 
324 static void notify_thresholds(__u64 msr_val)
325 {
326         /* check whether the interrupt handler is defined;
327          * otherwise simply return
328          */
329         if (!platform_thermal_notify)
330                 return;
331 
332         /* lower threshold reached */
333         if ((msr_val & THERM_LOG_THRESHOLD0) && thresh_event_valid(0))
334                 platform_thermal_notify(msr_val);
335         /* higher threshold reached */
336         if ((msr_val & THERM_LOG_THRESHOLD1) && thresh_event_valid(1))
337                 platform_thermal_notify(msr_val);
338 }
339 
340 /* Thermal transition interrupt handler */
341 static void intel_thermal_interrupt(void)
342 {
343         __u64 msr_val;
344 
345         rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
346 
347         /* Check for violation of core thermal thresholds*/
348         notify_thresholds(msr_val);
349 
350         if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
351                                 THERMAL_THROTTLING_EVENT,
352                                 CORE_LEVEL) != 0)
353                 mce_log_therm_throt_event(msr_val);
354 
355         if (this_cpu_has(X86_FEATURE_PLN))
356                 therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
357                                         POWER_LIMIT_EVENT,
358                                         CORE_LEVEL);
359 
360         if (this_cpu_has(X86_FEATURE_PTS)) {
361                 rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
362                 therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
363                                         THERMAL_THROTTLING_EVENT,
364                                         PACKAGE_LEVEL);
365                 if (this_cpu_has(X86_FEATURE_PLN))
366                         therm_throt_process(msr_val &
367                                         PACKAGE_THERM_STATUS_POWER_LIMIT,
368                                         POWER_LIMIT_EVENT,
369                                         PACKAGE_LEVEL);
370         }
371 }
372 
373 static void unexpected_thermal_interrupt(void)
374 {
375         printk(KERN_ERR "CPU%d: Unexpected LVT thermal interrupt!\n",
376                         smp_processor_id());
377 }
378 
379 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
380 
381 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
382 {
383         irq_enter();
384         exit_idle();
385         inc_irq_stat(irq_thermal_count);
386         smp_thermal_vector();
387         irq_exit();
388         /* Ack only at the end to avoid potential reentry */
389         ack_APIC_irq();
390 }
391 
392 /* Thermal monitoring depends on APIC, ACPI and clock modulation */
393 static int intel_thermal_supported(struct cpuinfo_x86 *c)
394 {
395         if (!cpu_has_apic)
396                 return 0;
397         if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
398                 return 0;
399         return 1;
400 }
401 
402 void __init mcheck_intel_therm_init(void)
403 {
404         /*
405          * This function is only called on boot CPU. Save the init thermal
406          * LVT value on BSP and use that value to restore APs' thermal LVT
407          * entry BIOS programmed later
408          */
409         if (intel_thermal_supported(&boot_cpu_data))
410                 lvtthmr_init = apic_read(APIC_LVTTHMR);
411 }
412 
413 void intel_init_thermal(struct cpuinfo_x86 *c)
414 {
415         unsigned int cpu = smp_processor_id();
416         int tm2 = 0;
417         u32 l, h;
418 
419         if (!intel_thermal_supported(c))
420                 return;
421 
422         /*
423          * First check if its enabled already, in which case there might
424          * be some SMM goo which handles it, so we can't even put a handler
425          * since it might be delivered via SMI already:
426          */
427         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
428 
429         h = lvtthmr_init;
430         /*
431          * The initial value of thermal LVT entries on all APs always reads
432          * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
433          * sequence to them and LVT registers are reset to 0s except for
434          * the mask bits which are set to 1s when APs receive INIT IPI.
435          * If BIOS takes over the thermal interrupt and sets its interrupt
436          * delivery mode to SMI (not fixed), it restores the value that the
437          * BIOS has programmed on AP based on BSP's info we saved since BIOS
438          * is always setting the same value for all threads/cores.
439          */
440         if ((h & APIC_DM_FIXED_MASK) != APIC_DM_FIXED)
441                 apic_write(APIC_LVTTHMR, lvtthmr_init);
442 
443 
444         if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
445                 printk(KERN_DEBUG
446                        "CPU%d: Thermal monitoring handled by SMI\n", cpu);
447                 return;
448         }
449 
450         /* Check whether a vector already exists */
451         if (h & APIC_VECTOR_MASK) {
452                 printk(KERN_DEBUG
453                        "CPU%d: Thermal LVT vector (%#x) already installed\n",
454                        cpu, (h & APIC_VECTOR_MASK));
455                 return;
456         }
457 
458         /* early Pentium M models use different method for enabling TM2 */
459         if (cpu_has(c, X86_FEATURE_TM2)) {
460                 if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
461                         rdmsr(MSR_THERM2_CTL, l, h);
462                         if (l & MSR_THERM2_CTL_TM_SELECT)
463                                 tm2 = 1;
464                 } else if (l & MSR_IA32_MISC_ENABLE_TM2)
465                         tm2 = 1;
466         }
467 
468         /* We'll mask the thermal vector in the lapic till we're ready: */
469         h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
470         apic_write(APIC_LVTTHMR, h);
471 
472         rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
473         if (cpu_has(c, X86_FEATURE_PLN))
474                 wrmsr(MSR_IA32_THERM_INTERRUPT,
475                       l | (THERM_INT_LOW_ENABLE
476                         | THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
477         else
478                 wrmsr(MSR_IA32_THERM_INTERRUPT,
479                       l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
480 
481         if (cpu_has(c, X86_FEATURE_PTS)) {
482                 rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
483                 if (cpu_has(c, X86_FEATURE_PLN))
484                         wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
485                               l | (PACKAGE_THERM_INT_LOW_ENABLE
486                                 | PACKAGE_THERM_INT_HIGH_ENABLE
487                                 | PACKAGE_THERM_INT_PLN_ENABLE), h);
488                 else
489                         wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
490                               l | (PACKAGE_THERM_INT_LOW_ENABLE
491                                 | PACKAGE_THERM_INT_HIGH_ENABLE), h);
492         }
493 
494         smp_thermal_vector = intel_thermal_interrupt;
495 
496         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
497         wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
498 
499         /* Unmask the thermal vector: */
500         l = apic_read(APIC_LVTTHMR);
501         apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
502 
503         printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
504                        tm2 ? "TM2" : "TM1");
505 
506         /* enable thermal throttle processing */
507         atomic_set(&therm_throt_en, 1);
508 }
509 

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