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Subject[ 35/37] x86, mce, therm_throt: Dont report power limit and package level thermal throttle events in mcelog
3.0-stable review patch.  If anyone has any objections, please let me know.


From: Fenghua Yu <>

commit 29e9bf1841e4f9df13b4992a716fece7087dd237 upstream.

Thermal throttle and power limit events are not defined as MCE errors in x86
architecture and should not generate MCE errors in mcelog.

Current kernel generates fake software defined MCE errors for these events.
This may confuse users because they may think the machine has real MCE errors
while actually only thermal throttle or power limit events happen.

To make it worse, buggy firmware on some platforms may falsely generate
the events. Therefore, kernel reports MCE errors which users think as real
hardware errors. Although the firmware bugs should be fixed, on the other hand,
kernel should not report MCE errors either.

So mcelog is not a good mechanism to report these events. To report the events, we count them in respective counters (core_power_limit_count,
package_power_limit_count, core_throttle_count, and package_throttle_count) in
/sys/devices/system/cpu/cpu#/thermal_throttle/. Users can check the counters
for each event on each CPU. Please note that all CPU's on one package report
duplicate counters. It's user application's responsibity to retrieve a package
level counter for one package.

This patch doesn't report package level power limit, core level power limit, and
package level thermal throttle events in mcelog. When the events happen, only
report them in respective counters in sysfs.

Since core level thermal throttle has been legacy code in kernel for a while and
users accepted it as MCE error in mcelog, core level thermal throttle is still
reported in mcelog. In the mean time, the event is counted in a counter in sysfs
as well.

Signed-off-by: Fenghua Yu <>
Acked-by: Borislav Petkov <>
Acked-by: Tony Luck <>
Signed-off-by: H. Peter Anvin <>
Cc: maximilian attems <>
Signed-off-by: Greg Kroah-Hartman <>

arch/x86/kernel/cpu/mcheck/therm_throt.c | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)

--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -322,17 +322,6 @@ device_initcall(thermal_throttle_init_de

#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)
static void notify_thresholds(__u64 msr_val)
/* check whether the interrupt handler is defined;
@@ -362,27 +351,23 @@ static void intel_thermal_interrupt(void
if (therm_throt_process(msr_val & THERM_STATUS_PROCHOT,
- mce_log_therm_throt_event(CORE_THROTTLED | msr_val);
+ mce_log_therm_throt_event(msr_val);

if (this_cpu_has(X86_FEATURE_PLN))
- if (therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
+ therm_throt_process(msr_val & THERM_STATUS_POWER_LIMIT,
- CORE_LEVEL) != 0)
- mce_log_therm_throt_event(CORE_POWER_LIMIT | msr_val);

if (this_cpu_has(X86_FEATURE_PTS)) {
rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
- if (therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
+ therm_throt_process(msr_val & PACKAGE_THERM_STATUS_PROCHOT,
- mce_log_therm_throt_event(PACKAGE_THROTTLED | msr_val);
if (this_cpu_has(X86_FEATURE_PLN))
- if (therm_throt_process(msr_val &
+ therm_throt_process(msr_val &
- mce_log_therm_throt_event(PACKAGE_POWER_LIMIT
- | msr_val);

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