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)
38 * Current thermal throttling state:
40 struct thermal_state {
44 unsigned long throttle_count;
45 unsigned long last_throttle_count;
48 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
50 static atomic_t therm_throt_en = ATOMIC_INIT(0);
52 static u32 lvtthmr_init __read_mostly;
55 #define define_therm_throt_sysdev_one_ro(_name) \
56 static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
58 #define define_therm_throt_sysdev_show_func(name) \
60 static ssize_t therm_throt_sysdev_show_##name( \
61 struct sys_device *dev, \
62 struct sysdev_attribute *attr, \
65 unsigned int cpu = dev->id; \
68 preempt_disable(); /* CPU hotplug */ \
69 if (cpu_online(cpu)) \
70 ret = sprintf(buf, "%lu\n", \
71 per_cpu(thermal_state, cpu).name); \
79 define_therm_throt_sysdev_show_func(throttle_count);
80 define_therm_throt_sysdev_one_ro(throttle_count);
82 static struct attribute *thermal_throttle_attrs[] = {
83 &attr_throttle_count.attr,
87 static struct attribute_group thermal_throttle_attr_group = {
88 .attrs = thermal_throttle_attrs,
89 .name = "thermal_throttle"
91 #endif /* CONFIG_SYSFS */
94 * therm_throt_process - Process thermal throttling event from interrupt
95 * @curr: Whether the condition is current or not (boolean), since the
96 * thermal interrupt normally gets called both when the thermal
97 * event begins and once the event has ended.
99 * This function is called by the thermal interrupt after the
100 * IRQ has been acknowledged.
102 * It will take care of rate limiting and printing messages to the syslog.
104 * Returns: 0 : Event should NOT be further logged, i.e. still in
105 * "timeout" from previous log message.
106 * 1 : Event should be logged further, and a message has been
107 * printed to the syslog.
109 static int therm_throt_process(bool is_throttled)
111 struct thermal_state *state;
112 unsigned int this_cpu;
116 this_cpu = smp_processor_id();
117 now = get_jiffies_64();
118 state = &per_cpu(thermal_state, this_cpu);
120 was_throttled = state->is_throttled;
121 state->is_throttled = is_throttled;
124 state->throttle_count++;
126 if (time_before64(now, state->next_check) &&
127 state->throttle_count != state->last_throttle_count)
130 state->next_check = now + CHECK_INTERVAL;
131 state->last_throttle_count = state->throttle_count;
133 /* if we just entered the thermal event */
135 printk(KERN_CRIT "CPU%d: Temperature above threshold, cpu clock throttled (total events = %lu)\n", this_cpu, state->throttle_count);
137 add_taint(TAINT_MACHINE_CHECK);
141 printk(KERN_INFO "CPU%d: Temperature/speed normal\n", this_cpu);
149 /* Add/Remove thermal_throttle interface for CPU device: */
150 static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
152 return sysfs_create_group(&sys_dev->kobj,
153 &thermal_throttle_attr_group);
156 static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
158 sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
161 /* Mutex protecting device creation against CPU hotplug: */
162 static DEFINE_MUTEX(therm_cpu_lock);
164 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
166 thermal_throttle_cpu_callback(struct notifier_block *nfb,
167 unsigned long action,
170 unsigned int cpu = (unsigned long)hcpu;
171 struct sys_device *sys_dev;
174 sys_dev = get_cpu_sysdev(cpu);
178 case CPU_UP_PREPARE_FROZEN:
179 mutex_lock(&therm_cpu_lock);
180 err = thermal_throttle_add_dev(sys_dev);
181 mutex_unlock(&therm_cpu_lock);
184 case CPU_UP_CANCELED:
185 case CPU_UP_CANCELED_FROZEN:
187 case CPU_DEAD_FROZEN:
188 mutex_lock(&therm_cpu_lock);
189 thermal_throttle_remove_dev(sys_dev);
190 mutex_unlock(&therm_cpu_lock);
193 return notifier_from_errno(err);
196 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
198 .notifier_call = thermal_throttle_cpu_callback,
201 static __init int thermal_throttle_init_device(void)
203 unsigned int cpu = 0;
206 if (!atomic_read(&therm_throt_en))
209 register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
211 #ifdef CONFIG_HOTPLUG_CPU
212 mutex_lock(&therm_cpu_lock);
214 /* connect live CPUs to sysfs */
215 for_each_online_cpu(cpu) {
216 err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
219 #ifdef CONFIG_HOTPLUG_CPU
220 mutex_unlock(&therm_cpu_lock);
225 device_initcall(thermal_throttle_init_device);
227 #endif /* CONFIG_SYSFS */
229 /* Thermal transition interrupt handler */
230 static void intel_thermal_interrupt(void)
234 rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
235 if (therm_throt_process((msr_val & THERM_STATUS_PROCHOT) != 0))
236 mce_log_therm_throt_event(msr_val);
239 static void unexpected_thermal_interrupt(void)
241 printk(KERN_ERR "CPU%d: Unexpected LVT TMR interrupt!\n",
243 add_taint(TAINT_MACHINE_CHECK);
246 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
248 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
252 inc_irq_stat(irq_thermal_count);
253 smp_thermal_vector();
255 /* Ack only at the end to avoid potential reentry */
259 /* Thermal monitoring depends on APIC, ACPI and clock modulation */
260 static int intel_thermal_supported(struct cpuinfo_x86 *c)
264 if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
269 void __init mcheck_intel_therm_init(void)
272 * This function is only called on boot CPU. Save the init thermal
273 * LVT value on BSP and use that value to restore APs' thermal LVT
274 * entry BIOS programmed later
276 if (intel_thermal_supported(&boot_cpu_data))
277 lvtthmr_init = apic_read(APIC_LVTTHMR);
280 void intel_init_thermal(struct cpuinfo_x86 *c)
282 unsigned int cpu = smp_processor_id();
286 if (!intel_thermal_supported(c))
290 * First check if its enabled already, in which case there might
291 * be some SMM goo which handles it, so we can't even put a handler
292 * since it might be delivered via SMI already:
294 rdmsr(MSR_IA32_MISC_ENABLE, l, h);
297 * The initial value of thermal LVT entries on all APs always reads
298 * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
299 * sequence to them and LVT registers are reset to 0s except for
300 * the mask bits which are set to 1s when APs receive INIT IPI.
301 * Always restore the value that BIOS has programmed on AP based on
302 * BSP's info we saved since BIOS is always setting the same value
303 * for all threads/cores
305 apic_write(APIC_LVTTHMR, lvtthmr_init);
309 if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
311 "CPU%d: Thermal monitoring handled by SMI\n", cpu);
315 /* Check whether a vector already exists */
316 if (h & APIC_VECTOR_MASK) {
318 "CPU%d: Thermal LVT vector (%#x) already installed\n",
319 cpu, (h & APIC_VECTOR_MASK));
323 /* early Pentium M models use different method for enabling TM2 */
324 if (cpu_has(c, X86_FEATURE_TM2)) {
325 if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
326 rdmsr(MSR_THERM2_CTL, l, h);
327 if (l & MSR_THERM2_CTL_TM_SELECT)
329 } else if (l & MSR_IA32_MISC_ENABLE_TM2)
333 /* We'll mask the thermal vector in the lapic till we're ready: */
334 h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
335 apic_write(APIC_LVTTHMR, h);
337 rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
338 wrmsr(MSR_IA32_THERM_INTERRUPT,
339 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
341 smp_thermal_vector = intel_thermal_interrupt;
343 rdmsr(MSR_IA32_MISC_ENABLE, l, h);
344 wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
346 /* Unmask the thermal vector: */
347 l = apic_read(APIC_LVTTHMR);
348 apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
350 printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
351 tm2 ? "TM2" : "TM1");
353 /* enable thermal throttle processing */
354 atomic_set(&therm_throt_en, 1);