1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/include/asm/shared/msr.h b/arch/x86/include/asm/shared/msr.h
new file mode 100644
index 000000000000..a20b1c08c99f
--- /dev/null
+++ b/arch/x86/include/asm/shared/msr.h
@@ -0,0 +1,30 @@
+/* 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;
+	};
+};
+
+/*
+ * The kernel proper already defines rdmsr()/wrmsr(), but they are not for the
+ * boot kernel since they rely on tracepoint/exception handling infrastructure
+ * that's not available here.
+ */
+static inline void raw_rdmsr(unsigned int reg, struct msr *m)
+{
+	asm volatile("rdmsr" : "=a" (m->l), "=d" (m->h) : "c" (reg));
+}
+
+static inline void raw_wrmsr(unsigned int reg, const struct msr *m)
+{
+	asm volatile("wrmsr" : : "c" (reg), "a"(m->l), "d" (m->h) : "memory");
+}
+
+#endif /* _ASM_X86_SHARED_MSR_H */