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15d5f839 DZ |
1 | /* |
2 | * linux/arch/i386/kerne/cpu/mcheck/therm_throt.c | |
3 | * | |
3222b36f DZ |
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). | |
15d5f839 DZ |
11 | * |
12 | * Author: Dmitriy Zavin (dmitriyz@google.com) | |
13 | * | |
14 | * Credits: Adapted from Zwane Mwaikambo's original code in mce_intel.c. | |
3222b36f | 15 | * Inspired by Ross Biro's and Al Borchers' counter code. |
15d5f839 DZ |
16 | */ |
17 | ||
18 | #include <linux/percpu.h> | |
3222b36f | 19 | #include <linux/sysdev.h> |
15d5f839 DZ |
20 | #include <linux/cpu.h> |
21 | #include <asm/cpu.h> | |
22 | #include <linux/notifier.h> | |
23 | #include <asm/therm_throt.h> | |
24 | ||
25 | /* How long to wait between reporting thermal events */ | |
26 | #define CHECK_INTERVAL (300 * HZ) | |
27 | ||
3222b36f DZ |
28 | static DEFINE_PER_CPU(__u64, next_check) = INITIAL_JIFFIES; |
29 | static DEFINE_PER_CPU(unsigned long, thermal_throttle_count); | |
30 | atomic_t therm_throt_en = ATOMIC_INIT(0); | |
31 | ||
32 | #ifdef CONFIG_SYSFS | |
33 | #define define_therm_throt_sysdev_one_ro(_name) \ | |
34 | static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL) | |
35 | ||
36 | #define define_therm_throt_sysdev_show_func(name) \ | |
37 | static ssize_t therm_throt_sysdev_show_##name(struct sys_device *dev, \ | |
38 | char *buf) \ | |
39 | { \ | |
40 | unsigned int cpu = dev->id; \ | |
41 | ssize_t ret; \ | |
42 | \ | |
43 | preempt_disable(); /* CPU hotplug */ \ | |
44 | if (cpu_online(cpu)) \ | |
45 | ret = sprintf(buf, "%lu\n", \ | |
46 | per_cpu(thermal_throttle_##name, cpu)); \ | |
47 | else \ | |
48 | ret = 0; \ | |
49 | preempt_enable(); \ | |
50 | \ | |
51 | return ret; \ | |
52 | } | |
53 | ||
54 | define_therm_throt_sysdev_show_func(count); | |
55 | define_therm_throt_sysdev_one_ro(count); | |
56 | ||
57 | static struct attribute *thermal_throttle_attrs[] = { | |
58 | &attr_count.attr, | |
59 | NULL | |
60 | }; | |
61 | ||
62 | static struct attribute_group thermal_throttle_attr_group = { | |
63 | .attrs = thermal_throttle_attrs, | |
64 | .name = "thermal_throttle" | |
65 | }; | |
66 | #endif /* CONFIG_SYSFS */ | |
15d5f839 DZ |
67 | |
68 | /*** | |
3222b36f | 69 | * therm_throt_process - Process thermal throttling event from interrupt |
15d5f839 DZ |
70 | * @curr: Whether the condition is current or not (boolean), since the |
71 | * thermal interrupt normally gets called both when the thermal | |
72 | * event begins and once the event has ended. | |
73 | * | |
3222b36f | 74 | * This function is called by the thermal interrupt after the |
15d5f839 DZ |
75 | * IRQ has been acknowledged. |
76 | * | |
77 | * It will take care of rate limiting and printing messages to the syslog. | |
78 | * | |
79 | * Returns: 0 : Event should NOT be further logged, i.e. still in | |
80 | * "timeout" from previous log message. | |
81 | * 1 : Event should be logged further, and a message has been | |
82 | * printed to the syslog. | |
83 | */ | |
84 | int therm_throt_process(int curr) | |
85 | { | |
86 | unsigned int cpu = smp_processor_id(); | |
66aea991 | 87 | __u64 tmp_jiffs = get_jiffies_64(); |
15d5f839 | 88 | |
3222b36f DZ |
89 | if (curr) |
90 | __get_cpu_var(thermal_throttle_count)++; | |
91 | ||
66aea991 | 92 | if (time_before64(tmp_jiffs, __get_cpu_var(next_check))) |
15d5f839 DZ |
93 | return 0; |
94 | ||
66aea991 | 95 | __get_cpu_var(next_check) = tmp_jiffs + CHECK_INTERVAL; |
15d5f839 DZ |
96 | |
97 | /* if we just entered the thermal event */ | |
98 | if (curr) { | |
99 | printk(KERN_CRIT "CPU%d: Temperature above threshold, " | |
3222b36f DZ |
100 | "cpu clock throttled (total events = %lu)\n", cpu, |
101 | __get_cpu_var(thermal_throttle_count)); | |
102 | ||
15d5f839 DZ |
103 | add_taint(TAINT_MACHINE_CHECK); |
104 | } else { | |
105 | printk(KERN_CRIT "CPU%d: Temperature/speed normal\n", cpu); | |
106 | } | |
107 | ||
108 | return 1; | |
109 | } | |
3222b36f DZ |
110 | |
111 | #ifdef CONFIG_SYSFS | |
112 | /* Add/Remove thermal_throttle interface for CPU device */ | |
113 | static __cpuinit int thermal_throttle_add_dev(struct sys_device * sys_dev) | |
114 | { | |
115 | sysfs_create_group(&sys_dev->kobj, &thermal_throttle_attr_group); | |
116 | return 0; | |
117 | } | |
118 | ||
119 | #ifdef CONFIG_HOTPLUG_CPU | |
120 | static __cpuinit int thermal_throttle_remove_dev(struct sys_device * sys_dev) | |
121 | { | |
122 | sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group); | |
123 | return 0; | |
124 | } | |
125 | ||
126 | /* Mutex protecting device creation against CPU hotplug */ | |
127 | static DEFINE_MUTEX(therm_cpu_lock); | |
128 | ||
129 | /* Get notified when a cpu comes on/off. Be hotplug friendly. */ | |
130 | static __cpuinit int thermal_throttle_cpu_callback(struct notifier_block *nfb, | |
131 | unsigned long action, | |
132 | void *hcpu) | |
133 | { | |
134 | unsigned int cpu = (unsigned long)hcpu; | |
135 | struct sys_device *sys_dev; | |
136 | ||
137 | sys_dev = get_cpu_sysdev(cpu); | |
138 | mutex_lock(&therm_cpu_lock); | |
139 | switch (action) { | |
140 | case CPU_ONLINE: | |
141 | thermal_throttle_add_dev(sys_dev); | |
142 | break; | |
143 | case CPU_DEAD: | |
144 | thermal_throttle_remove_dev(sys_dev); | |
145 | break; | |
146 | } | |
147 | mutex_unlock(&therm_cpu_lock); | |
148 | return NOTIFY_OK; | |
149 | } | |
150 | ||
151 | static struct notifier_block thermal_throttle_cpu_notifier = | |
152 | { | |
153 | .notifier_call = thermal_throttle_cpu_callback, | |
154 | }; | |
155 | #endif /* CONFIG_HOTPLUG_CPU */ | |
156 | ||
157 | static __init int thermal_throttle_init_device(void) | |
158 | { | |
159 | unsigned int cpu = 0; | |
160 | ||
161 | if (!atomic_read(&therm_throt_en)) | |
162 | return 0; | |
163 | ||
164 | register_hotcpu_notifier(&thermal_throttle_cpu_notifier); | |
165 | ||
166 | #ifdef CONFIG_HOTPLUG_CPU | |
167 | mutex_lock(&therm_cpu_lock); | |
168 | #endif | |
169 | /* connect live CPUs to sysfs */ | |
170 | for_each_online_cpu(cpu) | |
171 | thermal_throttle_add_dev(get_cpu_sysdev(cpu)); | |
172 | #ifdef CONFIG_HOTPLUG_CPU | |
173 | mutex_unlock(&therm_cpu_lock); | |
174 | #endif | |
175 | ||
176 | return 0; | |
177 | } | |
178 | ||
179 | device_initcall(thermal_throttle_init_device); | |
180 | #endif /* CONFIG_SYSFS */ |