x86 thermal: Disable power limit notification interrupt by default

The package power limit notification interrupt is primarily for
system diagnosis, and should not be blindly enabled on every
system by default -- particuarly since Linux does nothing in the
handler except count how many times it has been called...

Add a new kernel cmdline parameter "int_pln_enable" for situations where
users want to oberve these events via existing system counters:

$ grep TRM /proc/interrupts

$ grep . /sys/devices/system/cpu/cpu*/thermal_throttle/*

https://bugzilla.kernel.org/show_bug.cgi?id=36182

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6e3b18a..a7a1f34 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1158,6 +1158,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
                        Format: <irq>
 
+       int_pln_enable  [x86] Enable power limit notification interrupt
+
        intel_iommu=    [DMAR] Intel IOMMU driver (DMAR) option
                on
                        Enable intel iommu driver.

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 68fa890..f7feb2e 100644 (file)
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -210,6 +210,15 @@ static int thresh_event_valid(int event)
        return 1;
 }
 
+static bool int_pln_enable;
+static int __init int_pln_enable_setup(char *s)
+{
+       int_pln_enable = true;
+
+       return 1;
+}
+__setup("int_pln_enable", int_pln_enable_setup);
+
 #ifdef CONFIG_SYSFS
 /* Add/Remove thermal_throttle interface for CPU device: */
 static __cpuinit int thermal_throttle_add_dev(struct device *dev,
@@ -222,7 +231,7 @@ static __cpuinit int thermal_throttle_add_dev(struct device *dev,
        if (err)
                return err;
 
-       if (cpu_has(c, X86_FEATURE_PLN))
+       if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable)
                err = sysfs_add_file_to_group(&dev->kobj,
                                              &dev_attr_core_power_limit_count.attr,
                                              thermal_attr_group.name);
@@ -230,7 +239,7 @@ static __cpuinit int thermal_throttle_add_dev(struct device *dev,
                err = sysfs_add_file_to_group(&dev->kobj,
                                              &dev_attr_package_throttle_count.attr,
                                              thermal_attr_group.name);
-               if (cpu_has(c, X86_FEATURE_PLN))
+               if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable)
                        err = sysfs_add_file_to_group(&dev->kobj,
                                        &dev_attr_package_power_limit_count.attr,
                                        thermal_attr_group.name);
@@ -343,7 +352,7 @@ static void intel_thermal_interrupt(void)
                                CORE_LEVEL) != 0)
                mce_log_therm_throt_event(msr_val);
 
-       if (this_cpu_has(X86_FEATURE_PLN))
+       if (this_cpu_has(X86_FEATURE_PLN) && int_pln_enable)
                therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
                                        POWER_LIMIT_EVENT,
                                        CORE_LEVEL);
@@ -353,7 +362,7 @@ static void intel_thermal_interrupt(void)
                therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
                                        THERMAL_THROTTLING_EVENT,
                                        PACKAGE_LEVEL);
-               if (this_cpu_has(X86_FEATURE_PLN))
+               if (this_cpu_has(X86_FEATURE_PLN) && int_pln_enable)
                        therm_throt_process(msr_val &
                                        PACKAGE_THERM_STATUS_POWER_LIMIT,
                                        POWER_LIMIT_EVENT,
@@ -461,9 +470,13 @@ void intel_init_thermal(struct cpuinfo_x86 *c)
        apic_write(APIC_LVTTHMR, h);
 
        rdmsr(MSR_IA32_THERM_INTERRUPT, l, h);
-       if (cpu_has(c, X86_FEATURE_PLN))
+       if (cpu_has(c, X86_FEATURE_PLN) && !int_pln_enable)
+               wrmsr(MSR_IA32_THERM_INTERRUPT,
+                       (l | (THERM_INT_LOW_ENABLE
+                       | THERM_INT_HIGH_ENABLE)) & ~THERM_INT_PLN_ENABLE, h);
+       else if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable)
                wrmsr(MSR_IA32_THERM_INTERRUPT,
-                     l | (THERM_INT_LOW_ENABLE
+                       l | (THERM_INT_LOW_ENABLE
                        | THERM_INT_HIGH_ENABLE | THERM_INT_PLN_ENABLE), h);
        else
                wrmsr(MSR_IA32_THERM_INTERRUPT,
@@ -471,9 +484,14 @@ void intel_init_thermal(struct cpuinfo_x86 *c)
 
        if (cpu_has(c, X86_FEATURE_PTS)) {
                rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
-               if (cpu_has(c, X86_FEATURE_PLN))
+               if (cpu_has(c, X86_FEATURE_PLN) && !int_pln_enable)
                        wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
-                             l | (PACKAGE_THERM_INT_LOW_ENABLE
+                               (l | (PACKAGE_THERM_INT_LOW_ENABLE
+                               | PACKAGE_THERM_INT_HIGH_ENABLE))
+                               & ~PACKAGE_THERM_INT_PLN_ENABLE, h);
+               else if (cpu_has(c, X86_FEATURE_PLN) && int_pln_enable)
+                       wrmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT,
+                               l | (PACKAGE_THERM_INT_LOW_ENABLE
                                | PACKAGE_THERM_INT_HIGH_ENABLE
                                | PACKAGE_THERM_INT_PLN_ENABLE), h);
                else