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 static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES;
  38 static DEFINE_PER_CPU(unsigned long, thermal_throttle_count);
  39 static DEFINE_PER_CPU(bool, thermal_throttle_active);
  40
  41 static atomic_t therm_throt_en          = ATOMIC_INIT(0);
  42
  43 #ifdef CONFIG_SYSFS
  44 #define define_therm_throt_sysdev_one_ro(_name)                         \
  45         static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
  46
  47 #define define_therm_throt_sysdev_show_func(name)                       \
  48 static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev,   \
  49                                         struct sysdev_attribute *attr,  \
  50                                               char *buf)                \
  51 {                                                                       \
  52         unsigned int cpu = dev->id;                                     \
  53         ssize_t ret;                                                    \
  54                                                                         \
  55         preempt_disable();      /* CPU hotplug */                       \
  56         if (cpu_online(cpu))                                            \
  57                 ret = sprintf(buf, "%lu\n",                             \
  58                               per_cpu(thermal_throttle_##name, cpu));   \
  59         else                                                            \
  60                 ret = 0;                                                \
  61         preempt_enable();                                               \
  62                                                                         \
  63         return ret;                                                     \
  64 }
  65
  66 define_therm_throt_sysdev_show_func(count);
  67 define_therm_throt_sysdev_one_ro(count);
  68
  69 static struct attribute *thermal_throttle_attrs[] = {
  70         &attr_count.attr,
  71         NULL
  72 };
  73
  74 static struct attribute_group thermal_throttle_attr_group = {
  75         .attrs  = thermal_throttle_attrs,
  76         .name   = "thermal_throttle"
  77 };
  78 #endif /* CONFIG_SYSFS */
  79
  80 /***
  81  * therm_throt_process - Process thermal throttling event from interrupt
  82  * @curr: Whether the condition is current or not (boolean), since the
  83  *        thermal interrupt normally gets called both when the thermal
  84  *        event begins and once the event has ended.
  85  *
  86  * This function is called by the thermal interrupt after the
  87  * IRQ has been acknowledged.
  88  *
  89  * It will take care of rate limiting and printing messages to the syslog.
  90  *
  91  * Returns: 0 : Event should NOT be further logged, i.e. still in
  92  *              "timeout" from previous log message.
  93  *          1 : Event should be logged further, and a message has been
  94  *              printed to the syslog.
  95  */
  96 static int therm_throt_process(int curr)
  97 {
  98         unsigned int cpu = smp_processor_id();
  99         __u64 tmp_jiffs = get_jiffies_64();
 100         bool was_throttled = __get_cpu_var(thermal_throttle_active);
 101         bool is_throttled = __get_cpu_var(thermal_throttle_active) = curr;
 102
 103         if (is_throttled)
 104                 __get_cpu_var(thermal_throttle_count)++;
 105
 106         if (!(was_throttled ^ is_throttled) &&
 107             time_before64(tmp_jiffs, __get_cpu_var(next_check)))
 108                 return 0;
 109
 110         __get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL;
 111
 112         /* if we just entered the thermal event */
 113         if (is_throttled) {
 114                 printk(KERN_CRIT "CPU%d: Temperature above threshold, "
 115                        "cpu clock throttled (total events = %lu)\n",
 116                        cpu, __get_cpu_var(thermal_throttle_count));
 117
 118                 add_taint(TAINT_MACHINE_CHECK);
 119         } else if (was_throttled) {
 120                 printk(KERN_INFO "CPU%d: Temperature/speed normal\n", cpu);
 121         }
 122
 123         return 1;
 124 }
 125
 126 #ifdef CONFIG_SYSFS
 127 /* Add/Remove thermal_throttle interface for CPU device: */
 128 static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
 129 {
 130         return sysfs_create_group(&sys_dev->kobj,
 131                                   &thermal_throttle_attr_group);
 132 }
 133
 134 static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
 135 {
 136         sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
 137 }
 138
 139 /* Mutex protecting device creation against CPU hotplug: */
 140 static DEFINE_MUTEX(therm_cpu_lock);
 141
 142 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
 143 static __cpuinit int
 144 thermal_throttle_cpu_callback(struct notifier_block *nfb,
 145                               unsigned long action,
 146                               void *hcpu)
 147 {
 148         unsigned int cpu = (unsigned long)hcpu;
 149         struct sys_device *sys_dev;
 150         int err = 0;
 151
 152         sys_dev = get_cpu_sysdev(cpu);
 153
 154         switch (action) {
 155         case CPU_UP_PREPARE:
 156         case CPU_UP_PREPARE_FROZEN:
 157                 mutex_lock(&therm_cpu_lock);
 158                 err = thermal_throttle_add_dev(sys_dev);
 159                 mutex_unlock(&therm_cpu_lock);
 160                 WARN_ON(err);
 161                 break;
 162         case CPU_UP_CANCELED:
 163         case CPU_UP_CANCELED_FROZEN:
 164         case CPU_DEAD:
 165         case CPU_DEAD_FROZEN:
 166                 mutex_lock(&therm_cpu_lock);
 167                 thermal_throttle_remove_dev(sys_dev);
 168                 mutex_unlock(&therm_cpu_lock);
 169                 break;
 170         }
 171         return err ? NOTIFY_BAD : NOTIFY_OK;
 172 }
 173
 174 static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
 175 {
 176         .notifier_call = thermal_throttle_cpu_callback,
 177 };
 178
 179 static __init int thermal_throttle_init_device(void)
 180 {
 181         unsigned int cpu = 0;
 182         int err;
 183
 184         if (!atomic_read(&therm_throt_en))
 185                 return 0;
 186
 187         register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
 188
 189 #ifdef CONFIG_HOTPLUG_CPU
 190         mutex_lock(&therm_cpu_lock);
 191 #endif
 192         /* connect live CPUs to sysfs */
 193         for_each_online_cpu(cpu) {
 194                 err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
 195                 WARN_ON(err);
 196         }
 197 #ifdef CONFIG_HOTPLUG_CPU
 198         mutex_unlock(&therm_cpu_lock);
 199 #endif
 200
 201         return 0;
 202 }
 203 device_initcall(thermal_throttle_init_device);
 204
 205 #endif /* CONFIG_SYSFS */
 206
 207 /* Thermal transition interrupt handler */
 208 static void intel_thermal_interrupt(void)
 209 {
 210         __u64 msr_val;
 211
 212         rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
 213         if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT))
 214                 mce_log_therm_throt_event(msr_val);
 215 }
 216
 217 static void unexpected_thermal_interrupt(void)
 218 {
 219         printk(KERN_ERR "CPU%d: Unexpected LVT TMR interrupt!\n",
 220                         smp_processor_id());
 221         add_taint(TAINT_MACHINE_CHECK);
 222 }
 223
 224 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
 225
 226 asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
 227 {
 228         exit_idle();
 229         irq_enter();
 230         inc_irq_stat(irq_thermal_count);
 231         smp_thermal_vector();
 232         irq_exit();
 233         /* Ack only at the end to avoid potential reentry */
 234         ack_APIC_irq();
 235 }
 236
 237 void intel_init_thermal(struct cpuinfo_x86 *c)
 238 {
 239         unsigned int cpu = smp_processor_id();
 240         int tm2 = 0;
 241         u32 l, h;
 242
 243         /* Thermal monitoring depends on ACPI and clock modulation*/
 244         if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
 245                 return;
 246
 247         /*
 248          * First check if its enabled already, in which case there might
 249          * be some SMM goo which handles it, so we can't even put a handler
 250          * since it might be delivered via SMI already:
 251          */
 252         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
 253         h = apic_read(APIC_LVTTHMR);
 254         if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
 255                 printk(KERN_DEBUG
 256                        "CPU%d: Thermal monitoring handled by SMI\n", cpu);
 257                 return;
 258         }
 259
 260         if (cpu_has(c, X86_FEATURE_TM2) && (l & MSR_IA32_MISC_ENABLE_TM2))
 261                 tm2 = 1;
 262
 263         /* Check whether a vector already exists */
 264         if (h & APIC_VECTOR_MASK) {
 265                 printk(KERN_DEBUG
 266                        "CPU%d: Thermal LVT vector (%#x) already installed\n",
 267                        cpu, (h & APIC_VECTOR_MASK));
 268                 return;
 269         }
 270
 271         /* We'll mask the thermal vector in the lapic till we're ready: */
 272         h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
 273         apic_write(APIC_LVTTHMR, h);
 274
 275         rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
 276         wrmsr(MSR_IA32_THERM_INTERRUPT,
 277                 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
 278
 279         smp_thermal_vector = intel_thermal_interrupt;
 280
 281         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
 282         wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
 283
 284         /* Unmask the thermal vector: */
 285         l = apic_read(APIC_LVTTHMR);
 286         apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
 287
 288         printk(KERN_INFO "CPU%d: Thermal monitoring enabled (%s)\n",
 289                cpu, tm2 ? "TM2" : "TM1");
 290
 291         /* enable thermal throttle processing */
 292         atomic_set(&therm_throt_en, 1);
 293 }