sp1/amd64: tlb: Add TLB flush helper

Signed-off-by: Ian Moffett <ian@mirocom.org>

usr/src/sp1/head/amd64/tlb.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * All rights reserved.
+ *
+ * The following sources are CONFIDENTIAL and PROPRIETARY
+ * property of Mirocom Laboratories. Unauthorized copying,
+ * use, distribution or modification of this file, in whole
+ * and in part, is strictly prohibited without the prior written
+ * consent from Mirocom Laboratories.
+ */
+
+#ifndef _MACHINE_TLB_H_
+#define _MACHINE_TLB_H_ 1
+
+#include <sys/cdefs.h>
+
+/*
+ * Flush a single entry from the translation lookaside buffer
+ * to force it to be translated again.
+ */
+__always_inline static void
+md_tlb_flush(uintptr_t va)
+{
+    __asmv(
+        "invlpg (%0)"
+        :
+        : "r" (va)
+        : "memory"
+    );
+}
+
+#endif  /* !_MACHINE_TLB_H_ */