feat: add initial RISC-V architecture support and core kernel functionality

- Implement MMU hardware primitives for RISC-V SV39 in mmu.h
- Create trap vector control primitives in trap.h
- Define trap frame structure for RISC-V in trapframe.h
- Add assembly routines for context switching in swtch.S
- Implement trap vector entry/exit in trap_vector.S
- Introduce basic error number definitions in errno.h
- Provide placement new/delete operators in new.h
- Define kernel panic handler in panic.h and implement in panic.cc
- Establish basic type definitions in types.h
- Create the kernel main entry point in main.cc with global initialization
- Add synchronization primitives using spinlocks in spinlock.h and spinlock.cc
- Define per-CPU state tracking for interrupts in cpu_state.h
- Create a linker script for the kernel in linker.ld
- Update module makefiles for kernel and library components

1 files changed, 4 insertions, 4 deletions

diff --git a/include/ulib/errno.h b/include/ulib/errno.h
index c1691db..dd51598 100644
--- a/include/ulib/errno.h
+++ b/include/ulib/errno.h
@@ -1,11 +1,11 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
- * Copyright (C) 2026 Richard Qin
  * Lume OS - Linux Compatibility Layer
  *
  * This file aligns strictly with Linux RISC-V 64 ABI (asm-generic).
- * Reference: linux/include/uapi/asm-generic/errno-base.h
- * Reference: linux/include/uapi/asm-generic/errno.h
+ * The definitions are copied from the Linux kernel's UAPI headers
+ * (include/uapi/asm-generic/errno-base.h and include/uapi/asm-generic/errno.h)
+ * to ensure ABI compatibility. Original copyrights apply.
  */
 
 #ifndef _ERRNO_H