diff options
Diffstat (limited to 'arch/i386/kernel/cpu/mcheck/therm_throt.c')
| -rw-r--r-- | arch/i386/kernel/cpu/mcheck/therm_throt.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/mcheck/therm_throt.c b/arch/i386/kernel/cpu/mcheck/therm_throt.c new file mode 100644 index 000000000000..4f43047de406 --- /dev/null +++ b/arch/i386/kernel/cpu/mcheck/therm_throt.c @@ -0,0 +1,180 @@ +/* + * linux/arch/i386/kerne/cpu/mcheck/therm_throt.c + * + * Thermal throttle event support code (such as syslog messaging and rate + * limiting) that was factored out from x86_64 (mce_intel.c) and i386 (p4.c). + * This allows consistent reporting of CPU thermal throttle events. + * + * Maintains a counter in /sys that keeps track of the number of thermal + * events, such that the user knows how bad the thermal problem might be + * (since the logging to syslog and mcelog is rate limited). + * + * Author: Dmitriy Zavin (dmitriyz@google.com) + * + * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c. + * Inspired by Ross Biro's and Al Borchers' counter code. + */ + +#include <linux/percpu.h> +#include <linux/sysdev.h> +#include <linux/cpu.h> +#include <asm/cpu.h> +#include <linux/notifier.h> +#include <asm/therm_throt.h> + +/* How long to wait between reporting thermal events */ +#define CHECK_INTERVAL (300 * HZ) + +static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES; +static DEFINE_PER_CPU(unsigned long, thermal_throttle_count); +atomic_t therm_throt_en = ATOMIC_INIT(0); + +#ifdef CONFIG_SYSFS +#define define_therm_throt_sysdev_one_ro(_name) \ + static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL) + +#define define_therm_throt_sysdev_show_func(name) \ +static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev, \ + char *buf) \ +{ \ + unsigned int cpu = dev->id; \ + ssize_t ret; \ + \ + preempt_disable(); /* CPU hotplug */ \ + if (cpu_online(cpu)) \ + ret = sprintf(buf, "%lu\n", \ + per_cpu(thermal_throttle_##name, cpu)); \ + else \ + ret = 0; \ + preempt_enable(); \ + \ + return ret; \ +} + +define_therm_throt_sysdev_show_func(count); +define_therm_throt_sysdev_one_ro(count); + +static struct attribute *thermal_throttle_attrs[] = { + &attr_count.attr, + NULL +}; + +static struct attribute_group thermal_throttle_attr_group = { + .attrs = thermal_throttle_attrs, + .name = "thermal_throttle" +}; +#endif /* CONFIG_SYSFS */ + +/*** + * therm_throt_process - Process thermal throttling event from interrupt + * @curr: Whether the condition is current or not (boolean), since the + * thermal interrupt normally gets called both when the thermal + * event begins and once the event has ended. + * + * This function is called by the thermal interrupt after the + * IRQ has been acknowledged. + * + * It will take care of rate limiting and printing messages to the syslog. + * + * Returns: 0 : Event should NOT be further logged, i.e. still in + * "timeout" from previous log message. + * 1 : Event should be logged further, and a message has been + * printed to the syslog. + */ +int therm_throt_process(int curr) +{ + unsigned int cpu = smp_processor_id(); + __u64 tmp_jiffs = get_jiffies_64(); + + if (curr) + __get_cpu_var(thermal_throttle_count)++; + + if (time_before64(tmp_jiffs, __get_cpu_var(next_check))) + return 0; + + __get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL; + + /* if we just entered the thermal event */ + if (curr) { + printk(KERN_CRIT "CPU%d: Temperature above threshold, " + "cpu clock throttled (total events = %lu)\n", cpu, + __get_cpu_var(thermal_throttle_count)); + + add_taint(TAINT_MACHINE_CHECK); + } else { + printk(KERN_CRIT "CPU%d: Temperature/speed normal\n", cpu); + } + + return 1; +} + +#ifdef CONFIG_SYSFS +/* Add/Remove thermal_throttle interface for CPU device */ +static __cpuinit int thermal_throttle_add_dev(struct sys_device * sys_dev) +{ + sysfs_create_group(&sys_dev->kobj, &thermal_throttle_attr_group); + return 0; +} + +#ifdef CONFIG_HOTPLUG_CPU +static __cpuinit int thermal_throttle_remove_dev(struct sys_device * sys_dev) +{ + sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group); + return 0; +} + +/* Mutex protecting device creation against CPU hotplug */ +static DEFINE_MUTEX(therm_cpu_lock); + +/* Get notified when a cpu comes on/off. Be hotplug friendly. */ +static __cpuinit int thermal_throttle_cpu_callback(struct notifier_block *nfb, + unsigned long action, + void *hcpu) +{ + unsigned int cpu = (unsigned long)hcpu; + struct sys_device *sys_dev; + + sys_dev = get_cpu_sysdev(cpu); + mutex_lock(&therm_cpu_lock); + switch (action) { + case CPU_ONLINE: + thermal_throttle_add_dev(sys_dev); + break; + case CPU_DEAD: + thermal_throttle_remove_dev(sys_dev); + break; + } + mutex_unlock(&therm_cpu_lock); + return NOTIFY_OK; +} + +static struct notifier_block thermal_throttle_cpu_notifier = +{ + .notifier_call = thermal_throttle_cpu_callback, +}; +#endif /* CONFIG_HOTPLUG_CPU */ + +static __init int thermal_throttle_init_device(void) +{ + unsigned int cpu = 0; + + if (!atomic_read(&therm_throt_en)) + return 0; + + register_hotcpu_notifier(&thermal_throttle_cpu_notifier); + +#ifdef CONFIG_HOTPLUG_CPU + mutex_lock(&therm_cpu_lock); +#endif + /* connect live CPUs to sysfs */ + for_each_online_cpu(cpu) + thermal_throttle_add_dev(get_cpu_sysdev(cpu)); +#ifdef CONFIG_HOTPLUG_CPU + mutex_unlock(&therm_cpu_lock); +#endif + + return 0; +} + +device_initcall(thermal_throttle_init_device); +#endif /* CONFIG_SYSFS */ |