*introduce rd_msr/wr_msr helpers for boot kernel

mdroth · Feb 2, 2022 · 982c6c5 · 982c6c5
1 parent 207737b
commit 982c6c5
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Showing 3 changed files with 37 additions and 10 deletions.
diff --git a/arch/x86/boot/msr.h b/arch/x86/boot/msr.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Helpers/definitions related to MSR access.
+ */
+
+#ifndef BOOT_MSR_H
+#define BOOT_MSR_H
+
+#include <asm/shared/msr.h>
+
+static inline void rd_msr(unsigned int msr, struct msr *m)
+{
+	asm volatile("rdmsr" : "=a" (m->l), "=d" (m->h) : "c" (msr));
+}
+
+static inline void wr_msr(unsigned int msr, const struct msr *m)
+{
+	asm volatile("wrmsr" : : "c" (msr), "a"(m->l), "d" (m->h) : "memory");
+}
+
+#endif /* BOOT_MSR_H */
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
@@ -10,16 +10,7 @@
 #include <asm/errno.h>
 #include <asm/cpumask.h>
 #include <uapi/asm/msr.h>
-
-struct msr {
-	union {
-		struct {
-			u32 l;
-			u32 h;
-		};
-		u64 q;
-	};
-};
+#include <asm/shared/msr.h>
 
 struct msr_info {
 	u32 msr_no;

diff --git a/arch/x86/include/asm/shared/msr.h b/arch/x86/include/asm/shared/msr.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SHARED_MSR_H
+#define _ASM_X86_SHARED_MSR_H
+
+struct msr {
+	union {
+		struct {
+			u32 l;
+			u32 h;
+		};
+		u64 q;
+	};
+};
+
+#endif /* _ASM_X86_SHARED_MSR_H */