1 files changed, 55 insertions, 0 deletions
diff --git a/na/include/lume/kernel_map.h b/na/include/lume/kernel_map.h
new file mode 100644
index 0000000..7eafe88
--- /dev/null
+++ b/na/include/lume/kernel_map.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+#ifndef _LUME_KERNEL_MAP_H
+#define _LUME_KERNEL_MAP_H
+
+/*
+ * struct kernel_mapping — where the kernel image lives in physical and
+ * virtual memory.  Field names and order match Linux's
+ * arch/riscv/include/asm/page.h struct kernel_mapping so that:
+ *
+ *   1.  arch/riscv/kernel/head.S can do  `la a1, kernel_map`  then
+ *       `REG_L a1, KERNEL_MAP_VIRT_ADDR(a1)` and read the virtual
+ *       address.  The KERNEL_MAP_* asm constants come from
+ *       <generated/asm-offsets.h>, produced by arch/riscv/kernel/
+ *       asm-offsets.c at build time — re-order the struct and the
+ *       asm offsets follow automatically.
+ *
+ *   2.  arch/riscv/mm/init.c (Linux origin) populates the same fields
+ *       with the same semantics so no source edits are needed.
+ */
+
+#ifndef __ASSEMBLY__
+
+#include <lume/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct kernel_mapping {
+    unsigned long virt_addr;
+    unsigned long virt_offset;
+    uintptr_t     phys_addr;
+    uintptr_t     size;
+    unsigned long va_pa_offset;
+    unsigned long page_offset;
+    unsigned long va_kernel_pa_offset;
+};
+
+extern struct kernel_mapping kernel_map;
+
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* __ASSEMBLY__ */
+
+/* Assembly sees only the field offsets, picked up from the generated
+ * header.  Including the C struct above would be a parse error. */
+#include <generated/asm-offsets.h>
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _LUME_KERNEL_MAP_H */