[PATCH 5/5] x86/MCE: Save MCA control bits that get set in hardware

[Ghannam, Yazen]

From: Yazen Ghannam <yazen.ghannam@xxxxxxx>

The OS is expected to write all bits in MCA_CTL. However, only
implemented bits get set in the hardware.

Read back MCA_CTL so that the value in the hardware is saved and
reported through sysfs.

Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
 arch/x86/kernel/cpu/mce/core.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 4a066c1e8ab2..ed5374ab3ac3 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1566,10 +1566,13 @@ static void __mcheck_cpu_init_clear_banks(void)
 	for (i = 0; i < this_cpu_read(num_banks); i++) {
 		struct mce_bank *b = &this_cpu_read(mce_banks)[i];
 
-		if (!b->init)
-			continue;
-		wrmsrl(msr_ops.ctl(i), b->ctl);
-		wrmsrl(msr_ops.status(i), 0);
+		if (b->init) {
+			wrmsrl(msr_ops.ctl(i), b->ctl);
+			wrmsrl(msr_ops.status(i), 0);
+		}
+
+		/* Save bits set in hardware. */
+		rdmsrl(msr_ops.ctl(i), b->ctl);
 	}
 }
 
@@ -2313,8 +2316,10 @@ static void mce_reenable_cpu(void)
 	for (i = 0; i < this_cpu_read(num_banks); i++) {
 		struct mce_bank *b = &this_cpu_read(mce_banks)[i];
 
-		if (b->init)
+		if (b->init) {
 			wrmsrl(msr_ops.ctl(i), b->ctl);
+			rdmsrl(msr_ops.ctl(i), b->ctl);
+		}
 	}
 }
 
-- 
2.17.1