[GIT PULL] RAS urgent for 5.5

[Borislav Petkov]

Hi Linus,

one urgent fix for the thermal throttling machinery: the recent change
reworking the thermal notifications forgot to mask out read-only and
reserved bits in the thermal status MSRs, leading to exceptions while
writing those MSRs. The fix below takes care of masking out those bits
first.

Please pull,
thanks.

---
The following changes since commit c2da5bdc66a377f0b82ee959f19f5a6774706b83:

  Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (2019-11-26 17:12:12 -0800)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git ras-urgent-for-linus

for you to fetch changes up to 5a43b87b3c62ad149ba6e9d0d3e5c0e5da02a5ca:

  x86/mce/therm_throt: Mask out read-only and reserved MSR bits (2019-11-29 09:17:52 +0100)

----------------------------------------------------------------
Srinivas Pandruvada (1):
      x86/mce/therm_throt: Mask out read-only and reserved MSR bits

 arch/x86/kernel/cpu/mce/therm_throt.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/therm_throt.c b/arch/x86/kernel/cpu/mce/therm_throt.c
index d01e0da0163a..b38010b541d6 100644
--- a/arch/x86/kernel/cpu/mce/therm_throt.c
+++ b/arch/x86/kernel/cpu/mce/therm_throt.c
@@ -195,17 +195,24 @@ static const struct attribute_group thermal_attr_group = {
 #define THERM_THROT_POLL_INTERVAL	HZ
 #define THERM_STATUS_PROCHOT_LOG	BIT(1)
 
+#define THERM_STATUS_CLEAR_CORE_MASK (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11) | BIT(13) | BIT(15))
+#define THERM_STATUS_CLEAR_PKG_MASK  (BIT(1) | BIT(3) | BIT(5) | BIT(7) | BIT(9) | BIT(11))
+
 static void clear_therm_status_log(int level)
 {
 	int msr;
-	u64 msr_val;
+	u64 mask, msr_val;
 
-	if (level == CORE_LEVEL)
-		msr = MSR_IA32_THERM_STATUS;
-	else
-		msr = MSR_IA32_PACKAGE_THERM_STATUS;
+	if (level == CORE_LEVEL) {
+		msr  = MSR_IA32_THERM_STATUS;
+		mask = THERM_STATUS_CLEAR_CORE_MASK;
+	} else {
+		msr  = MSR_IA32_PACKAGE_THERM_STATUS;
+		mask = THERM_STATUS_CLEAR_PKG_MASK;
+	}
 
 	rdmsrl(msr, msr_val);
+	msr_val &= mask;
 	wrmsrl(msr, msr_val & ~THERM_STATUS_PROCHOT_LOG);
 }
 
-- 
Regards/Gruss,
    Boris.

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