1003ed4bbce4ebe3351157ebceffae8a5ecb4b40
[linux-2.6.git] / arch / x86 / kernel / cpu / mcheck / therm_throt.c
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/sysdev.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 /*
38  * Current thermal throttling state:
39  */
40 struct thermal_state {
41         bool                    is_throttled;
42
43         u64                     next_check;
44         unsigned long           throttle_count;
45         unsigned long           last_throttle_count;
46 };
47
48 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
49
50 static atomic_t therm_throt_en  = ATOMIC_INIT(0);
51
52 static u32 lvtthmr_init __read_mostly;
53
54 #ifdef CONFIG_SYSFS
55 #define define_therm_throt_sysdev_one_ro(_name)                         \
56         static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
57
58 #define define_therm_throt_sysdev_show_func(name)                       \
59                                                                         \
60 static ssize_t therm_throt_sysdev_show_##name(                          \
61                         struct sys_device *dev,                         \
62                         struct sysdev_attribute *attr,                  \
63                         char *buf)                                      \
64 {                                                                       \
65         unsigned int cpu = dev->id;                                     \
66         ssize_t ret;                                                    \
67                                                                         \
68         preempt_disable();      /* CPU hotplug */                       \
69         if (cpu_online(cpu))                                            \
70                 ret = sprintf(buf, "%lu\n",                             \
71                               per_cpu(thermal_state, cpu).name);        \
72         else                                                            \
73                 ret = 0;                                                \
74         preempt_enable();                                               \
75                                                                         \
76         return ret;                                                     \
77 }
78
79 define_therm_throt_sysdev_show_func(throttle_count);
80 define_therm_throt_sysdev_one_ro(throttle_count);
81
82 static struct attribute *thermal_throttle_attrs[] = {
83         &attr_throttle_count.attr,
84         NULL
85 };
86
87 static struct attribute_group thermal_throttle_attr_group = {
88         .attrs  = thermal_throttle_attrs,
89         .name   = "thermal_throttle"
90 };
91 #endif /* CONFIG_SYSFS */
92
93 /***
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.
98  *
99  * This function is called by the thermal interrupt after the
100  * IRQ has been acknowledged.
101  *
102  * It will take care of rate limiting and printing messages to the syslog.
103  *
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.
108  */
109 static int therm_throt_process(bool is_throttled)
110 {
111         struct thermal_state *state;
112         unsigned int this_cpu;
113         bool was_throttled;
114         u64 now;
115
116         this_cpu = smp_processor_id();
117         now = get_jiffies_64();
118         state = &per_cpu(thermal_state, this_cpu);
119
120         was_throttled = state->is_throttled;
121         state->is_throttled = is_throttled;
122
123         if (is_throttled)
124                 state->throttle_count++;
125
126         if (time_before64(now, state->next_check) &&
127                         state->throttle_count != state->last_throttle_count)
128                 return 0;
129
130         state->next_check = now + CHECK_INTERVAL;
131         state->last_throttle_count = state->throttle_count;
132
133         /* if we just entered the thermal event */
134         if (is_throttled) {
135                 printk(KERN_CRIT "CPU%d: Temperature above threshold, cpu clock throttled (total events = %lu)\n", this_cpu, state->throttle_count);
136
137                 add_taint(TAINT_MACHINE_CHECK);
138                 return 1;
139         }
140         if (was_throttled) {
141                 printk(KERN_INFO "CPU%d: Temperature/speed normal\n", this_cpu);
142                 return 1;
143         }
144
145         return 0;
146 }
147
148 #ifdef CONFIG_SYSFS
149 /* Add/Remove thermal_throttle interface for CPU device: */
150 static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
151 {
152         return sysfs_create_group(&sys_dev->kobj,
153                                   &thermal_throttle_attr_group);
154 }
155
156 static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
157 {
158         sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
159 }
160
161 /* Mutex protecting device creation against CPU hotplug: */
162 static DEFINE_MUTEX(therm_cpu_lock);
163
164 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
165 static __cpuinit int
166 thermal_throttle_cpu_callback(struct notifier_block *nfb,
167                               unsigned long action,
168                               void *hcpu)
169 {
170         unsigned int cpu = (unsigned long)hcpu;
171         struct sys_device *sys_dev;
172         int err = 0;
173
174         sys_dev = get_cpu_sysdev(cpu);
175
176         switch (action) {
177         case CPU_UP_PREPARE:
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);
182                 WARN_ON(err);
183                 break;
184         case CPU_UP_CANCELED:
185         case CPU_UP_CANCELED_FROZEN:
186         case CPU_DEAD:
187         case CPU_DEAD_FROZEN:
188                 mutex_lock(&therm_cpu_lock);
189                 thermal_throttle_remove_dev(sys_dev);
190                 mutex_unlock(&therm_cpu_lock);
191                 break;
192         }
193         return err ? NOTIFY_BAD : NOTIFY_OK;
194 }
195
196 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
197 {
198         .notifier_call = thermal_throttle_cpu_callback,
199 };
200
201 static __init int thermal_throttle_init_device(void)
202 {
203         unsigned int cpu = 0;
204         int err;
205
206         if (!atomic_read(&therm_throt_en))
207                 return 0;
208
209         register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
210
211 #ifdef CONFIG_HOTPLUG_CPU
212         mutex_lock(&therm_cpu_lock);
213 #endif
214         /* connect live CPUs to sysfs */
215         for_each_online_cpu(cpu) {
216                 err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
217                 WARN_ON(err);
218         }
219 #ifdef CONFIG_HOTPLUG_CPU
220         mutex_unlock(&therm_cpu_lock);
221 #endif
222
223         return 0;
224 }
225 device_initcall(thermal_throttle_init_device);
226
227 #endif /* CONFIG_SYSFS */
228
229 /* Thermal transition interrupt handler */
230 static void intel_thermal_interrupt(void)
231 {
232         __u64 msr_val;
233
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);
237 }
238
239 static void unexpected_thermal_interrupt(void)
240 {
241         printk(KERN_ERR "CPU%d: Unexpected LVT TMR interrupt!\n",
242                         smp_processor_id());
243         add_taint(TAINT_MACHINE_CHECK);
244 }
245
246 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
247
248 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
249 {
250         exit_idle();
251         irq_enter();
252         inc_irq_stat(irq_thermal_count);
253         smp_thermal_vector();
254         irq_exit();
255         /* Ack only at the end to avoid potential reentry */
256         ack_APIC_irq();
257 }
258
259 void __init mcheck_intel_therm_init(void)
260 {
261         /*
262          * This function is only called on boot CPU. Save the init thermal
263          * LVT value on BSP and use that value to restore APs' thermal LVT
264          * entry BIOS programmed later
265          */
266         if (cpu_has(&boot_cpu_data, X86_FEATURE_ACPI) &&
267                 cpu_has(&boot_cpu_data, X86_FEATURE_ACC))
268                 lvtthmr_init = apic_read(APIC_LVTTHMR);
269 }
270
271 void intel_init_thermal(struct cpuinfo_x86 *c)
272 {
273         unsigned int cpu = smp_processor_id();
274         int tm2 = 0;
275         u32 l, h;
276
277         /* Thermal monitoring depends on ACPI and clock modulation*/
278         if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
279                 return;
280
281         /*
282          * First check if its enabled already, in which case there might
283          * be some SMM goo which handles it, so we can't even put a handler
284          * since it might be delivered via SMI already:
285          */
286         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
287
288         /*
289          * The initial value of thermal LVT entries on all APs always reads
290          * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
291          * sequence to them and LVT registers are reset to 0s except for
292          * the mask bits which are set to 1s when APs receive INIT IPI.
293          * Always restore the value that BIOS has programmed on AP based on
294          * BSP's info we saved since BIOS is always setting the same value
295          * for all threads/cores
296          */
297         apic_write(APIC_LVTTHMR, lvtthmr_init);
298
299         h = lvtthmr_init;
300
301         if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
302                 printk(KERN_DEBUG
303                        "CPU%d: Thermal monitoring handled by SMI\n", cpu);
304                 return;
305         }
306
307         /* Check whether a vector already exists */
308         if (h & APIC_VECTOR_MASK) {
309                 printk(KERN_DEBUG
310                        "CPU%d: Thermal LVT vector (%#x) already installed\n",
311                        cpu, (h & APIC_VECTOR_MASK));
312                 return;
313         }
314
315         /* early Pentium M models use different method for enabling TM2 */
316         if (cpu_has(c, X86_FEATURE_TM2)) {
317                 if (c->x86 == 6 && (c->x86_model == 9 || c->x86_model == 13)) {
318                         rdmsr(MSR_THERM2_CTL, l, h);
319                         if (l & MSR_THERM2_CTL_TM_SELECT)
320                                 tm2 = 1;
321                 } else if (l & MSR_IA32_MISC_ENABLE_TM2)
322                         tm2 = 1;
323         }
324
325         /* We'll mask the thermal vector in the lapic till we're ready: */
326         h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
327         apic_write(APIC_LVTTHMR, h);
328
329         rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
330         wrmsr(MSR_IA32_THERM_INTERRUPT,
331                 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
332
333         smp_thermal_vector = intel_thermal_interrupt;
334
335         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
336         wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
337
338         /* Unmask the thermal vector: */
339         l = apic_read(APIC_LVTTHMR);
340         apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
341
342         printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
343                        tm2 ? "TM2" : "TM1");
344
345         /* enable thermal throttle processing */
346         atomic_set(&therm_throt_en, 1);
347 }