From c3ae5ba68dc418a5d5de6d67c3aacbfdb1bf2305 Mon Sep 17 00:00:00 2001
From: Chloe M <chloe@yiffware.org>
Date: Fri, 10 Jul 2026 20:56:46 -0400
Subject: [PATCH] ptos/amd64: tlb: Add TLB operation helpers

Signed-off-by: Chloe M <chloe@mensia.org>
---
 service/ptos/head/arch/amd64/tlb.h | 52 ++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 service/ptos/head/arch/amd64/tlb.h

diff --git a/service/ptos/head/arch/amd64/tlb.h b/service/ptos/head/arch/amd64/tlb.h
new file mode 100644
index 0000000..b7d9ac5
--- /dev/null
+++ b/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_ */