[PATH V2 4/5] Package Level Thermal Control and Power Limit Notification: power limit

[Fenghua Yu]

From: Fenghua Yu <fenghua.yu@xxxxxxxxx>

Power limit notification feature is published in Intel 64 and IA-32
Architectures SDMV Vol 3A 14.5.6 Power Limit Notification.

It is implemented first on Intel Sandy Bridge platform.

The patch handles notification interrupt. Interrupt handler dumps power limit
information in log_buf, logs the event in mce log, and increases the event
counters (core_power_limit and package_power_limit). Upper level applications
could use the data to detect system health or diagnose functionality/performance
issues.

In the future, the event could be handled in a more fancy way.

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Len Brown <len.brown@xxxxxxxxx>
---
 arch/x86/include/asm/msr-index.h         |    4 +
 arch/x86/kernel/cpu/mcheck/therm_throt.c |  186 +++++++++++++++++++++---------
 2 files changed, 136 insertions(+), 54 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index f1c1b82..f3c8a7a 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -226,10 +226,12 @@
 
 #define THERM_INT_HIGH_ENABLE		(1 << 0)
 #define THERM_INT_LOW_ENABLE		(1 << 1)
+#define THERM_INT_PLN_ENABLE		(1 << 24)
 
 #define MSR_IA32_THERM_STATUS		0x0000019c
 
 #define THERM_STATUS_PROCHOT		(1 << 0)
+#define THERM_STATUS_POWER_LIMIT	(1 << 10)
 
 #define MSR_THERM2_CTL			0x0000019d
 
@@ -242,11 +244,13 @@
 #define MSR_IA32_PACKAGE_THERM_STATUS		0x000001b1
 
 #define PACKAGE_THERM_STATUS_PROCHOT		(1 << 0)
+#define PACKAGE_THERM_STATUS_POWER_LIMIT	(1 << 10)
 
 #define MSR_IA32_PACKAGE_THERM_INTERRUPT	0x000001b2
 
 #define PACKAGE_THERM_INT_HIGH_ENABLE		(1 << 0)
 #define PACKAGE_THERM_INT_LOW_ENABLE		(1 << 1)
+#define PACKAGE_THERM_INT_PLN_ENABLE		(1 << 24)
 
 /* MISC_ENABLE bits: architectural */
 #define MSR_IA32_MISC_ENABLE_FAST_STRING	(1ULL << 0)
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index d307f9f..0c3d1e0 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -34,20 +34,25 @@
 /* How long to wait between reporting thermal events */
 #define CHECK_INTERVAL		(300 * HZ)
 
+#define THERMAL_THROTTLING_EVENT	0
+#define POWER_LIMIT_EVENT		1
+
 /*
- * Current thermal throttling state:
+ * Current thermal event state:
  */
 struct _thermal_state {
-	bool			is_throttled;
-
+	bool			new_event;
+	int			event;
 	u64			next_check;
-	unsigned long		throttle_count;
-	unsigned long		last_throttle_count;
+	unsigned long		count;
+	unsigned long		last_count;
 };
 
 struct thermal_state {
-	struct _thermal_state core;
-	struct _thermal_state package;
+	struct _thermal_state core_throttle;
+	struct _thermal_state core_power_limit;
+	struct _thermal_state package_throttle;
+	struct _thermal_state package_power_limit;
 };
 
 static DEFINE_PER_CPU(struct thermal_state, thermal_state);
@@ -62,9 +67,9 @@ static u32 lvtthmr_init __read_mostly;
 			   therm_throt_sysdev_show_##_name,		\
 				   NULL)				\
 
-#define define_therm_throt_sysdev_show_func(level, name)		\
+#define define_therm_throt_sysdev_show_func(event, name)		\
 									\
-static ssize_t therm_throt_sysdev_show_##level##_##name(		\
+static ssize_t therm_throt_sysdev_show_##event##_##name(		\
 			struct sys_device *dev,				\
 			struct sysdev_attribute *attr,			\
 			char *buf)					\
@@ -75,7 +80,7 @@ static ssize_t therm_throt_sysdev_show_##level##_##name(		\
 	preempt_disable();	/* CPU hotplug */			\
 	if (cpu_online(cpu)) {						\
 		ret = sprintf(buf, "%lu\n",				\
-			      per_cpu(thermal_state, cpu).level.name);	\
+			      per_cpu(thermal_state, cpu).event.name);	\
 	} else								\
 		ret = 0;						\
 	preempt_enable();						\
@@ -83,23 +88,32 @@ static ssize_t therm_throt_sysdev_show_##level##_##name(		\
 	return ret;							\
 }
 
-define_therm_throt_sysdev_show_func(core, throttle_count);
+define_therm_throt_sysdev_show_func(core_throttle, count);
 define_therm_throt_sysdev_one_ro(core_throttle_count);
 
-define_therm_throt_sysdev_show_func(package, throttle_count);
+define_therm_throt_sysdev_show_func(core_power_limit, count);
+define_therm_throt_sysdev_one_ro(core_power_limit_count);
+
+define_therm_throt_sysdev_show_func(package_throttle, count);
 define_therm_throt_sysdev_one_ro(package_throttle_count);
 
+define_therm_throt_sysdev_show_func(package_power_limit, count);
+define_therm_throt_sysdev_one_ro(package_power_limit_count);
+
 static struct attribute *thermal_throttle_attrs[] = {
 	&attr_core_throttle_count.attr,
 	NULL
 };
 
-static struct attribute_group thermal_throttle_attr_group = {
+static struct attribute_group thermal_attr_group = {
 	.attrs	= thermal_throttle_attrs,
 	.name	= "thermal_throttle"
 };
 #endif /* CONFIG_SYSFS */
 
+#define CORE_LEVEL	0
+#define PACKAGE_LEVEL	1
+
 /***
  * therm_throt_process - Process thermal throttling event from interrupt
  * @curr: Whether the condition is current or not (boolean), since the
@@ -116,49 +130,73 @@ static struct attribute_group thermal_throttle_attr_group = {
  *          1 : Event should be logged further, and a message has been
  *              printed to the syslog.
  */
-#define CORE_LEVEL	0
-#define PACKAGE_LEVEL	1
-static int therm_throt_process(bool is_throttled, int level)
+static int therm_throt_process(bool new_event, int event, int level)
 {
 	struct _thermal_state *state;
-	unsigned int this_cpu;
-	bool was_throttled;
+	unsigned int this_cpu = smp_processor_id();
+	bool old_event;
 	u64 now;
+	struct thermal_state *pstate = &per_cpu(thermal_state, this_cpu);
+
+	if (!new_event)
+		return 0;
 
-	this_cpu = smp_processor_id();
 	now = get_jiffies_64();
-	if (level == CORE_LEVEL)
-		state = &per_cpu(thermal_state, this_cpu).core;
-	else
-		state = &per_cpu(thermal_state, this_cpu).package;
+	if (level == CORE_LEVEL) {
+		if (event == THERMAL_THROTTLING_EVENT)
+			state = &pstate->core_throttle;
+		else if (event == POWER_LIMIT_EVENT)
+			state = &pstate->core_power_limit;
+		else
+			 return 0;
+	} else if (level == PACKAGE_LEVEL) {
+		if (event == THERMAL_THROTTLING_EVENT)
+			state = &pstate->package_throttle;
+		else if (event == POWER_LIMIT_EVENT)
+			state = &pstate->package_power_limit;
+		else
+			return 0;
+	} else
+		return 0;
 
-	was_throttled = state->is_throttled;
-	state->is_throttled = is_throttled;
+	old_event = state->new_event;
+	state->new_event = new_event;
 
-	if (is_throttled)
-		state->throttle_count++;
+	if (new_event)
+		state->count++;
 
 	if (time_before64(now, state->next_check) &&
-			state->throttle_count != state->last_throttle_count)
+			state->count != state->last_count)
 		return 0;
 
 	state->next_check = now + CHECK_INTERVAL;
-	state->last_throttle_count = state->throttle_count;
+	state->last_count = state->count;
 
 	/* if we just entered the thermal event */
-	if (is_throttled) {
-		printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
-		      this_cpu,
-		      level == CORE_LEVEL ? "Core" : "Package",
-		      state->throttle_count);
+	if (new_event) {
+		if (event == THERMAL_THROTTLING_EVENT)
+			printk(KERN_CRIT "CPU%d: %s temperature above threshold, cpu clock throttled (total events = %lu)\n",
+				this_cpu,
+				level == CORE_LEVEL ? "Core" : "Package",
+				state->count);
+		else
+			printk(KERN_CRIT "CPU%d: %s power limit notification (total events = %lu)\n",
+				this_cpu,
+				level == CORE_LEVEL ? "Core" : "Package",
+				state->count);
 
 		add_taint(TAINT_MACHINE_CHECK);
 		return 1;
 	}
-	if (was_throttled) {
-		printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
-		       this_cpu,
-		       level == CORE_LEVEL ? "Core" : "Package");
+	if (old_event) {
+		if (event == THERMAL_THROTTLING_EVENT)
+			printk(KERN_INFO "CPU%d: %s temperature/speed normal\n",
+				this_cpu,
+				level == CORE_LEVEL ? "Core" : "Package");
+		else
+			printk(KERN_INFO "CPU%d: %s power limit normal\n",
+				this_cpu,
+				level == CORE_LEVEL ? "Core" : "Package");
 		return 1;
 	}
 
@@ -172,21 +210,29 @@ static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
 	int err;
 	struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
 
-	err = sysfs_create_group(&sys_dev->kobj, &thermal_throttle_attr_group);
+	err = sysfs_create_group(&sys_dev->kobj, &thermal_attr_group);
 	if (err)
 		return err;
 
+	if (cpu_has(c, X86_FEATURE_PLN))
+		err = sysfs_add_file_to_group(&sys_dev->kobj,
+					      &attr_core_power_limit_count.attr,
+					      thermal_attr_group.name);
 	if (cpu_has(c, X86_FEATURE_PTS))
 		err = sysfs_add_file_to_group(&sys_dev->kobj,
 					      &attr_package_throttle_count.attr,
-					      thermal_throttle_attr_group.name);
+					      thermal_attr_group.name);
+		if (cpu_has(c, X86_FEATURE_PLN))
+			err = sysfs_add_file_to_group(&sys_dev->kobj,
+					&attr_package_power_limit_count.attr,
+					thermal_attr_group.name);
 
 	return err;
 }
 
 static __cpuinit void thermal_throttle_remove_dev(struct sys_device *sys_dev)
 {
-	sysfs_remove_group(&sys_dev->kobj, &thermal_throttle_attr_group);
+	sysfs_remove_group(&sys_dev->kobj, &thermal_attr_group);
 }
 
 /* Mutex protecting device creation against CPU hotplug: */
@@ -257,6 +303,17 @@ device_initcall(thermal_throttle_init_device);
 
 #endif /* CONFIG_SYSFS */
 
+/*
+ * Set up the most two significant bit to notify mce log that this thermal
+ * event type.
+ * This is a temp solution. May be changed in the future with mce log
+ * infrasture.
+ */
+#define CORE_THROTTLED		(0)
+#define CORE_POWER_LIMIT	((__u64)1 << 62)
+#define PACKAGE_THROTTLED	((__u64)2 << 62)
+#define PACKAGE_POWER_LIMIT	((__u64)3 << 62)
+
 /* Thermal transition interrupt handler */
 static void intel_thermal_interrupt(void)
 {
@@ -264,21 +321,31 @@ static void intel_thermal_interrupt(void)
 	struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
 
 	rdmsrl(MSR_IA32_THERM_STATUS, msr_val);
+
 	if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
+				THERMAL_THROTTLING_EVENT,
 				CORE_LEVEL) != 0)
-		mce_log_therm_throt_event(msr_val);
+		mce_log_therm_throt_event(CORE_THROTTLED | msr_val);
+
+	if (cpu_has(c, X86_FEATURE_PLN))
+		if (therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
+					POWER_LIMIT_EVENT,
+					CORE_LEVEL) != 0)
+			mce_log_therm_throt_event(CORE_POWER_LIMIT | msr_val);
 
 	if (cpu_has(c, X86_FEATURE_PTS)) {
 		rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
 		if (therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
+					THERMAL_THROTTLING_EVENT,
 					PACKAGE_LEVEL) != 0)
-			/*
-			 * Set up the most significant bit to notify mce log
-			 * that this thermal event is a package level event.
-			 * This is a temp solution. May be changed in the future
-			 * with mce log infrasture.
-			 */
-			mce_log_therm_throt_event(((__u64)1 << 63) | msr_val);
+			mce_log_therm_throt_event(PACKAGE_THROTTLED | msr_val);
+		if (cpu_has(c, X86_FEATURE_PLN))
+			if (therm_throt_process(msr_val &
+					PACKAGE_THERM_STATUS_POWER_LIMIT,
+					POWER_LIMIT_EVENT,
+					PACKAGE_LEVEL) != 0)
+				mce_log_therm_throt_event(PACKAGE_POWER_LIMIT
+							  | msr_val);
 	}
 }
 
@@ -381,14 +448,25 @@ void intel_init_thermal(struct cpuinfo_x86 *c)
 	apic_write(APIC_LVTTHMR, h);
 
 	rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
-	wrmsr(MSR_IA32_THERM_INTERRUPT,
-		l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
+	if (cpu_has(c, X86_FEATURE_PLN))
+		wrmsr(MSR_IA32_THERM_INTERRUPT,
+		      l | (THERM_INT_LOW_ENABLE
+			| THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
+	else
+		wrmsr(MSR_IA32_THERM_INTERRUPT,
+		      l | (THERM_INT_LOW_ENABLE | THERM_INT_HIGH_ENABLE), h);
 
 	if (cpu_has(c, X86_FEATURE_PTS)) {
 		rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
-		wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
-			l | (PACKAGE_THERM_INT_LOW_ENABLE
-		  | PACKAGE_THERM_INT_HIGH_ENABLE), h);
+		if (cpu_has(c, X86_FEATURE_PLN))
+			wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
+			      l | (PACKAGE_THERM_INT_LOW_ENABLE
+				| PACKAGE_THERM_INT_HIGH_ENABLE
+				| PACKAGE_THERM_INT_PLN_ENABLE), h);
+		else
+			wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
+			      l | (PACKAGE_THERM_INT_LOW_ENABLE
+				| PACKAGE_THERM_INT_HIGH_ENABLE), h);
 	}
 
 	smp_thermal_vector = intel_thermal_interrupt;
-- 
1.7.2

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