ptos/amd64: tlb: Add TLB operation helpers

Signed-off-by: Chloe M <chloe@mensia.org>

service/ptos/head/arch/amd64/tlb.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: TLB related helpers
+ * Author:      Chloe M.
+ */
+
+#ifndef _MACHINE_TLB_H_
+#define _MACHINE_TLB_H_ 1
+
+#include <ptdef.h>
+#include <hal/page.h>
+
+/*
+ * Flush a single virtual address from the translation
+ * lookaside buffer.
+ *
+ * @VirtualBase:  Virtual address to flush
+ */
+ALWAYS_INLINE static inline VOID
+MdTlbFlushSingle(UPTR VirtualBase)
+{
+    VirtualBase = ALIGN_DOWN(VirtualBase, PAGESIZE);
+    ASMV(
+        "invlpg %0"
+        :
+        : "m" (VirtualBase)
+        : "memory"
+    );
+}
+
+/*
+ * Flush all entries from the translation lookaside buffer.
+ *
+ * XXX: This should be used quite judiciously due to the
+ *      collateral damage caused by this operation which
+ *      incurs a large performance penalty.
+ */
+ALWAYS_INLINE static inline VOID
+MdTlbFlushAll(VOID)
+{
+    ASMV(
+        "mov %%cr3, %%rax\n"
+        "mov %%rax, %%cr3"
+        :
+        :
+        : "memory", "rax"
+    );
+}
+
+#endif  /* !_MACHINE_TLB_H_ */