[coreboot-gerrit] Change in coreboot[master]: cpu/x86/msr.h: Turn `msr_t` into a union

[Angel Pons (Code Review)]

Angel Pons has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/52547 )

Change subject: cpu/x86/msr.h: Turn `msr_t` into a union
......................................................................

cpu/x86/msr.h: Turn `msr_t` into a union

This allows treating MSR values as one 64-bit value, which may be more
convenient in some cases. Also add a compile-time size check.

Change-Id: Ia8ac87296628855968005371f8acf2ca486d6c1a
Signed-off-by: Angel Pons 
---
M src/include/cpu/x86/msr.h
1 file changed, 8 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/47/52547/1

diff --git a/src/include/cpu/x86/msr.h b/src/include/cpu/x86/msr.h
index 5ae3ddf..fc98d03 100644
--- a/src/include/cpu/x86/msr.h
+++ b/src/include/cpu/x86/msr.h
@@ -95,12 +95,17 @@
 #define IA32_CR_SF_QOS_MASK_2           0x1892

#ifndef __ASSEMBLER__
+#include <assert.h>
 #include <types.h>

-typedef struct msr_struct {
-	unsigned int lo;
-	unsigned int hi;
+typedef union {
+	struct {
+		unsigned int lo;
+		unsigned int hi;
+	};
+	uint64_t value;
 } msr_t;
+_Static_assert(sizeof(msr_t) == sizeof(uint64_t), "Size of msr_t is incorrect");

typedef struct msrinit_struct {
    unsigned int index;