1 files changed, 56 insertions, 0 deletions
diff --git a/i386/i386/msr.h b/i386/i386/msr.h
new file mode 100644
index 00000000..8f09b80b
--- /dev/null
+++ b/i386/i386/msr.h
@@ -0,0 +1,56 @@
+/*
+ *  Copyright (C) 2023 Free Software Foundation
+ *
+ * This program is free software ; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation ; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY ; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the program ; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _MACHINE_MSR_H_
+#define _MACHINE_MSR_H_
+
+#define MSR_REG_EFER  0xC0000080
+#define MSR_REG_STAR  0xC0000081
+#define MSR_REG_LSTAR 0xC0000082
+#define MSR_REG_CSTAR 0xC0000083
+#define MSR_REG_FMASK 0xC0000084
+#define MSR_REG_FSBASE 0xC0000100
+#define MSR_REG_GSBASE 0xC0000101
+
+#define MSR_EFER_SCE  0x00000001
+
+#ifndef __ASSEMBLER__
+
+static inline void wrmsr(uint32_t regaddr, uint64_t value)
+{
+  uint32_t low = (uint32_t) value, high = ((uint32_t) (value >> 32));
+  asm volatile("wrmsr"
+               :
+               : "c" (regaddr), "a" (low), "d" (high)
+               : "memory"  /* wrmsr may cause a read from memory, so
+                            * make the compiler flush any changes */
+               );
+}
+
+static inline uint64_t rdmsr(uint32_t regaddr)
+{
+  uint32_t low, high;
+  asm volatile("rdmsr"
+               : "=a" (low), "=d" (high)
+               : "c" (regaddr)
+               );
+  return ((uint64_t)high << 32) | low;
+}
+#endif /* __ASSEMBLER__ */
+
+#endif /* _MACHINE_MSR_H_ */