LXR linux/arch/x86/kernel/cpu/mcheck/therm

   1/*
   2 * linux/arch/i386/kernel/cpu/mcheck/therm_throt.c
   3 *
   4 * Thermal throttle event support code (such as syslog messaging and rate
   5 * limiting) that was factored out from x86_64 (mce_intel.c) and i386 (p4.c).
   6 * This allows consistent reporting of CPU thermal throttle events.
   7 *
   8 * Maintains a counter in /sys that keeps track of the number of thermal
   9 * events, such that the user knows how bad the thermal problem might be
  10 * (since the logging to syslog and mcelog is rate limited).
  11 *
  12 * Author: Dmitriy Zavin (dmitriyz@google.com)
  13 *
  14 * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c.
  15 *          Inspired by Ross Biro's and Al Borchers' counter code.
  16 */
  17
  18#include <linux/percpu.h>
  19#include <linux/sysdev.h>
  20#include <linux/cpu.h>
  21#include <asm/cpu.h>
  22#include <linux/notifier.h>
  23#include <linux/jiffies.h>
  24#include <asm/therm_throt.h>
  25
  26/* How long to wait between reporting thermal events */
  27#define CHECK_INTERVAL              (300 * HZ)
  28
  29static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES;
  30static DEFINE_PER_CPU(unsigned long, thermal_throttle_count);
  31atomic_t therm_throt_en = ATOMIC_INIT(0);
  32
  33#ifdef CONFIG_SYSFS
  34#define define_therm_throt_sysdev_one_ro(_name)                              \
  35        static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
  36
  37#define define_therm_throt_sysdev_show_func(name)                            \
  38static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev,        \
  39                                              char *buf)                     \
  40{                                                                            \
  41        unsigned int cpu = dev->id;                                          \
  42        ssize_t ret;                                                         \
  43                                                                             \
  44        preempt_disable();              /* CPU hotplug */                    \
  45        if (cpu_online(cpu))                                                 \
  46                ret = sprintf(buf, "%lu\n",                                  \
  47                              per_cpu(thermal_throttle_##name, cpu));        \
  48        else                                                                 \
  49                ret = 0;                                                     \
  50        preempt_enable();                                                    \
  51                                                                             \
  52        return ret;                                                          \
  53}
  54
  55define_therm_throt_sysdev_show_func(count);
  56define_therm_throt_sysdev_one_ro(count);
  57
  58static struct attribute *thermal_throttle_attrs[] = {
  59        &attr_count.attr,
  60        NULL
  61};
  62
  63static struct attribute_group thermal_throttle_attr_group = {
  64        .attrs = thermal_throttle_attrs,
  65        .name = "thermal_throttle"
  66};
  67#endif /* CONFIG_SYSFS */
  68
  69/***
  70 * therm_throt_process - Process thermal throttling event from interrupt
  71 * @curr: Whether the condition is current or not (boolean), since the
  72 *        thermal interrupt normally gets called both when the thermal
  73 *        event begins and once the event has ended.
  74 *
  75 * This function is called by the thermal interrupt after the
  76 * IRQ has been acknowledged.
  77 *
  78 * It will take care of rate limiting and printing messages to the syslog.
  79 *
  80 * Returns: 0 : Event should NOT be further logged, i.e. still in
  81 *              "timeout" from previous log message.
  82 *          1 : Event should be logged further, and a message has been
  83 *              printed to the syslog.
  84 */
  85int therm_throt_process(int curr)
  86{
  87        unsigned int cpu = smp_processor_id();
  88        __u64 tmp_jiffs = get_jiffies_64();
  89
  90        if (curr)
  91                __get_cpu_var(thermal_throttle_count)++;
  92
  93        if (time_before64(tmp_jiffs, __get_cpu_var(next_check)))
  94                return 0;
  95
  96        __get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL;
  97
  98        /* if we just entered the thermal event */
  99        if (curr) {
 100                printk(KERN_CRIT "CPU%d: Temperature above threshold, "
 101                       "cpu clock throttled (total events = %lu)\n", cpu,
 102                       __get_cpu_var(thermal_throttle_count));
 103
 104                add_taint(TAINT_MACHINE_CHECK);
 105        } else {
 106                printk(KERN_CRIT "CPU%d: Temperature/speed normal\n", cpu);
 107        }
 108
 109        return 1;
 110}
 111
 112#ifdef CONFIG_SYSFS
 113/* Add/Remove thermal_throttle interface for CPU device */
 114static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
 115{
 116        return sysfs_create_group(&sys_dev->kobj, &thermal_throttle_attr_group);
 117}
 118
 119static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
 120{
 121        return sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
 122}
 123
 124/* Mutex protecting device creation against CPU hotplug */
 125static DEFINE_MUTEX(therm_cpu_lock);
 126
 127/* Get notified when a cpu comes on/off. Be hotplug friendly. */
 128static __cpuinit int thermal_throttle_cpu_callback(struct notifier_block *nfb,
 129                                                   unsigned long action,
 130                                                   void *hcpu)
 131{
 132        unsigned int cpu = (unsigned long)hcpu;
 133        struct sys_device *sys_dev;
 134        int err = 0;
 135
 136        sys_dev = get_cpu_sysdev(cpu);
 137        switch (action) {
 138        case CPU_UP_PREPARE:
 139        case CPU_UP_PREPARE_FROZEN:
 140                mutex_lock(&therm_cpu_lock);
 141                err = thermal_throttle_add_dev(sys_dev);
 142                mutex_unlock(&therm_cpu_lock);
 143                WARN_ON(err);
 144                break;
 145        case CPU_UP_CANCELED:
 146        case CPU_UP_CANCELED_FROZEN:
 147        case CPU_DEAD:
 148        case CPU_DEAD_FROZEN:
 149                mutex_lock(&therm_cpu_lock);
 150                thermal_throttle_remove_dev(sys_dev);
 151                mutex_unlock(&therm_cpu_lock);
 152                break;
 153        }
 154        return err ? NOTIFY_BAD : NOTIFY_OK;
 155}
 156
 157static struct notifier_block thermal_throttle_cpu_notifier __cpuinitdata =
 158{
 159        .notifier_call = thermal_throttle_cpu_callback,
 160};
 161
 162static __init int thermal_throttle_init_device(void)
 163{
 164        unsigned int cpu = 0;
 165        int err;
 166
 167        if (!atomic_read(&therm_throt_en))
 168                return 0;
 169
 170        register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
 171
 172#ifdef CONFIG_HOTPLUG_CPU
 173        mutex_lock(&therm_cpu_lock);
 174#endif
 175        /* connect live CPUs to sysfs */
 176        for_each_online_cpu(cpu) {
 177                err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
 178                WARN_ON(err);
 179        }
 180#ifdef CONFIG_HOTPLUG_CPU
 181        mutex_unlock(&therm_cpu_lock);
 182#endif
 183
 184        return 0;
 185}
 186
 187device_initcall(thermal_throttle_init_device);
 188#endif /* CONFIG_SYSFS */
 189