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 };
  46
  47 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
  48
  49 static atomic_t therm_throt_en  = ATOMIC_INIT(0);
  50
  51 #ifdef CONFIG_SYSFS
  52 #define define_therm_throt_sysdev_one_ro(_name)                         \
  53         static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
  54
  55 #define define_therm_throt_sysdev_show_func(name)                       \
  56                                                                         \
  57 static ssize_t therm_throt_sysdev_show_##name(                          \
  58                         struct sys_device *dev,                         \
  59                         struct sysdev_attribute *attr,                  \
  60                         char *buf)                                      \
  61 {                                                                       \
  62         unsigned int cpu = dev->id;                                     \
  63         ssize_t ret;                                                    \
  64                                                                         \
  65         preempt_disable();      /* CPU hotplug */                       \
  66         if (cpu_online(cpu))                                            \
  67                 ret = sprintf(buf, "%lu\n",                             \
  68                               per_cpu(thermal_state, cpu).name);        \
  69         else                                                            \
  70                 ret = 0;                                                \
  71         preempt_enable();                                               \
  72                                                                         \
  73         return ret;                                                     \
  74 }
  75
  76 define_therm_throt_sysdev_show_func(throttle_count);
  77 define_therm_throt_sysdev_one_ro(throttle_count);
  78
  79 static struct attribute *thermal_throttle_attrs[] = {
  80         &attr_throttle_count.attr,
  81         NULL
  82 };
  83
  84 static struct attribute_group thermal_throttle_attr_group = {
  85         .attrs  = thermal_throttle_attrs,
  86         .name   = "thermal_throttle"
  87 };
  88 #endif /* CONFIG_SYSFS */
  89
  90 /***
  91  * therm_throt_process - Process thermal throttling event from interrupt
  92  * @curr: Whether the condition is current or not (boolean), since the
  93  *        thermal interrupt normally gets called both when the thermal
  94  *        event begins and once the event has ended.
  95  *
  96  * This function is called by the thermal interrupt after the
  97  * IRQ has been acknowledged.
  98  *
  99  * It will take care of rate limiting and printing messages to the syslog.
 100  *
 101  * Returns: 0 : Event should NOT be further logged, i.e. still in
 102  *              "timeout" from previous log message.
 103  *          1 : Event should be logged further, and a message has been
 104  *              printed to the syslog.
 105  */
 106 static int therm_throt_process(bool is_throttled)
 107 {
 108         struct thermal_state *state;
 109         unsigned int this_cpu;
 110         bool was_throttled;
 111         u64 now;
 112
 113         this_cpu = smp_processor_id();
 114         now = get_jiffies_64();
 115         state = &per_cpu(thermal_state, this_cpu);
 116
 117         was_throttled = state->is_throttled;
 118         state->is_throttled = is_throttled;
 119
 120         if (is_throttled)
 121                 state->throttle_count++;
 122
 123         if (!(was_throttled ^ is_throttled) &&
 124                         time_before64(now, state->next_check))
 125                 return 0;
 126
 127         state->next_check = now + CHECK_INTERVAL;
 128
 129         /* if we just entered the thermal event */
 130         if (is_throttled) {
 131                 printk(KERN_CRIT "CPU%d: Temperature above threshold, cpu clock throttled (total events = %lu)\n", this_cpu, state->throttle_count);
 132
 133                 add_taint(TAINT_MACHINE_CHECK);
 134                 return 1;
 135         }
 136         if (was_throttled) {
 137                 printk(KERN_INFO "CPU%d: Temperature/speed normal\n", this_cpu);
 138                 return 1;
 139         }
 140
 141         return 0;
 142 }
 143
 144 #ifdef CONFIG_SYSFS
 145 /* Add/Remove thermal_throttle interface for CPU device: */
 146 static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
 147 {
 148         return sysfs_create_group(&sys_dev->kobj,
 149                                   &thermal_throttle_attr_group);
 150 }
 151
 152 static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
 153 {
 154         sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
 155 }
 156
 157 /* Mutex protecting device creation against CPU hotplug: */
 158 static DEFINE_MUTEX(therm_cpu_lock);
 159
 160 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
 161 static __cpuinit int
 162 thermal_throttle_cpu_callback(struct notifier_block *nfb,
 163                               unsigned long action,
 164                               void *hcpu)
 165 {
 166         unsigned int cpu = (unsigned long)hcpu;
 167         struct sys_device *sys_dev;
 168         int err = 0;
 169
 170         sys_dev = get_cpu_sysdev(cpu);
 171
 172         switch (action) {
 173         case CPU_UP_PREPARE:
 174         case CPU_UP_PREPARE_FROZEN:
 175                 mutex_lock(&therm_cpu_lock);
 176                 err = thermal_throttle_add_dev(sys_dev);
 177                 mutex_unlock(&therm_cpu_lock);
 178                 WARN_ON(err);
 179                 break;
 180         case CPU_UP_CANCELED:
 181         case CPU_UP_CANCELED_FROZEN:
 182         case CPU_DEAD:
 183         case CPU_DEAD_FROZEN:
 184                 mutex_lock(&therm_cpu_lock);
 185                 thermal_throttle_remove_dev(sys_dev);
 186                 mutex_unlock(&therm_cpu_lock);
 187                 break;
 188         }
 189         return err ? NOTIFY_BAD : NOTIFY_OK;
 190 }
 191
 192 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
 193 {
 194         .notifier_call = thermal_throttle_cpu_callback,
 195 };
 196
 197 static __init int thermal_throttle_init_device(void)
 198 {
 199         unsigned int cpu = 0;
 200         int err;
 201
 202         if (!atomic_read(&therm_throt_en))
 203                 return 0;
 204
 205         register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
 206
 207 #ifdef CONFIG_HOTPLUG_CPU
 208         mutex_lock(&therm_cpu_lock);
 209 #endif
 210         /* connect live CPUs to sysfs */
 211         for_each_online_cpu(cpu) {
 212                 err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
 213                 WARN_ON(err);
 214         }
 215 #ifdef CONFIG_HOTPLUG_CPU
 216         mutex_unlock(&therm_cpu_lock);
 217 #endif
 218
 219         return 0;
 220 }
 221 device_initcall(thermal_throttle_init_device);
 222
 223 #endif /* CONFIG_SYSFS */
 224
 225 /* Thermal transition interrupt handler */
 226 static void intel_thermal_interrupt(void)
 227 {
 228         __u64 msr_val;
 229
 230         rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
 231         if (therm_throt_process((msr_val & THERM_STATUS_PROCHOT) != 0))
 232                 mce_log_therm_throt_event(msr_val);
 233 }
 234
 235 static void unexpected_thermal_interrupt(void)
 236 {
 237         printk(KERN_ERR "CPU%d: Unexpected LVT TMR interrupt!\n",
 238                         smp_processor_id());
 239         add_taint(TAINT_MACHINE_CHECK);
 240 }
 241
 242 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
 243
 244 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
 245 {
 246         exit_idle();
 247         irq_enter();
 248         inc_irq_stat(irq_thermal_count);
 249         smp_thermal_vector();
 250         irq_exit();
 251         /* Ack only at the end to avoid potential reentry */
 252         ack_APIC_irq();
 253 }
 254
 255 void intel_init_thermal(struct cpuinfo_x86 *c)
 256 {
 257         unsigned int cpu = smp_processor_id();
 258         int tm2 = 0;
 259         u32 l, h;
 260
 261         /* Thermal monitoring depends on ACPI and clock modulation*/
 262         if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
 263                 return;
 264
 265         /*
 266          * First check if its enabled already, in which case there might
 267          * be some SMM goo which handles it, so we can't even put a handler
 268          * since it might be delivered via SMI already:
 269          */
 270         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
 271         h = apic_read(APIC_LVTTHMR);
 272         if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
 273                 printk(KERN_DEBUG
 274                        "CPU%d: Thermal monitoring handled by SMI\n", cpu);
 275                 return;
 276         }
 277
 278         if (cpu_has(c, X86_FEATURE_TM2) && (l & MSR_IA32_MISC_ENABLE_TM2))
 279                 tm2 = 1;
 280
 281         /* Check whether a vector already exists */
 282         if (h & APIC_VECTOR_MASK) {
 283                 printk(KERN_DEBUG
 284                        "CPU%d: Thermal LVT vector (%#x) already installed\n",
 285                        cpu, (h & APIC_VECTOR_MASK));
 286                 return;
 287         }
 288
 289         /* We'll mask the thermal vector in the lapic till we're ready: */
 290         h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
 291         apic_write(APIC_LVTTHMR, h);
 292
 293         rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
 294         wrmsr(MSR_IA32_THERM_INTERRUPT,
 295                 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
 296
 297         smp_thermal_vector = intel_thermal_interrupt;
 298
 299         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
 300         wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
 301
 302         /* Unmask the thermal vector: */
 303         l = apic_read(APIC_LVTTHMR);
 304         apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
 305
 306         printk(KERN_INFO "CPU%d: Thermal monitoring enabled (%s)\n",
 307                cpu, tm2 ? "TM2" : "TM1");
 308
 309         /* enable thermal throttle processing */
 310         atomic_set(&therm_throt_en, 1);
 311 }