x86/mce/therm_throt: Mask out read-only and reserved MSR bits

While writing to MSR IA32_THERM_STATUS/IA32_PKG_THERM_STATUS, avoid
writing 1 to read only and reserved fields because updating some fields
generates exception.

 [ bp: Vertically align for better readability. ]

Fixes: f665620 ("x86/mce/therm_throt: Optimize notifications of thermal throttle")
Reported-by: Dominik Brodowski <[email protected]>
Tested-by: Dominik Brodowski <[email protected]>
Signed-off-by: Srinivas Pandruvada <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: linux-edac <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: spandruvada

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);
 }