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         if (cpu_has(c, X86_FEATURE_TM2) && (l & MSR_IA32_MISC_ENABLE_TM2))
 308                 tm2 = 1;
 309
 310         /* Check whether a vector already exists */
 311         if (h & APIC_VECTOR_MASK) {
 312                 printk(KERN_DEBUG
 313                        "CPU%d: Thermal LVT vector (%#x) already installed\n",
 314                        cpu, (h & APIC_VECTOR_MASK));
 315                 return;
 316         }
 317
 318         /* We'll mask the thermal vector in the lapic till we're ready: */
 319         h = THERMAL_APIC_VECTOR | APIC_DM_FIXED | APIC_LVT_MASKED;
 320         apic_write(APIC_LVTTHMR, h);
 321
 322         rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
 323         wrmsr(MSR_IA32_THERM_INTERRUPT,
 324                 l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
 325
 326         smp_thermal_vector = intel_thermal_interrupt;
 327
 328         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
 329         wrmsr(MSR_IA32_MISC_ENABLE, l | MSR_IA32_MISC_ENABLE_TM1, h);
 330
 331         /* Unmask the thermal vector: */
 332         l = apic_read(APIC_LVTTHMR);
 333         apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
 334
 335         printk(KERN_INFO "CPU%d: Thermal monitoring enabled (%s)\n",
 336                cpu, tm2 ? "TM2" : "TM1");
 337
 338         /* enable thermal throttle processing */
 339         atomic_set(&therm_throt_en, 1);
 340 }