feat: add boot self-tests for various kernel components

- Implemented a self-test runner in `selftest.cc` to invoke all test suites.
- Added tests for atomic operations in `test_atomic.cc`, covering construction, store/load, exchange, arithmetic, and compare-and-swap.
- Created tests for the Flattened Device Tree (FDT) in `test_fdt.cc`, verifying node access and compatibility queries.
- Developed a comprehensive Physical Memory Manager (PMM) test suite in `test_pmm.cc`, including allocation, deallocation, reference counting, and boundary conditions.
- Implemented Red-Black Tree tests in `test_rbtree.cc`, validating insertion, deletion, and iteration.
- Added Slab Allocator tests in `test_slab.cc`, covering various allocation sizes, edge cases, and operator overloads.
- Created Spinlock tests in `test_spinlock.cc`, ensuring proper locking behavior and interrupt state preservation.
- Developed Virtual Memory Area (VMA) tests in `test_vma.cc`, validating region mapping, unmapping, and fault handling.
- Added tests for Virtual Memory Management (VMM) in `test_vmm.cc`, verifying address translation and page alignment.

1 files changed, 41 insertions, 0 deletions

diff --git a/na/test/selftest.cc b/na/test/selftest.cc
new file mode 100644
index 0000000..a992ae2
--- /dev/null
+++ b/na/test/selftest.cc
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+/*
+ * Boot Self-Test Runner
+ *
+ * Entry point that invokes all registered self-test suites.
+ * Called from kernel_main() after all subsystem initialization.
+ */
+
+#include <lume/selftest.h>
+
+/* Individual test suite entry points */
+void selftest_pmm();
+void selftest_slab();
+void selftest_spinlock();
+void selftest_rbtree();
+void selftest_vmm();
+void selftest_fdt();
+void selftest_vma();
+void selftest_atomic();
+
+void selftest_run_all()
+{
+    early_puts("\n========================================\n");
+    early_puts("  Boot Self-Test Suite\n");
+    early_puts("========================================\n");
+
+    selftest_spinlock();
+    selftest_pmm();
+    selftest_slab();
+    selftest_rbtree();
+    selftest_vmm();
+    selftest_vma();
+    selftest_atomic();
+    selftest_fdt();
+
+    early_puts("========================================\n");
+    early_puts("  All self-tests PASSED\n");
+    early_puts("========================================\n\n");
+}