kernel: add Tab system for resource allocation and tracking

oro-kernel/Cargo.toml

@@ -13,8 +13,20 @@ license = "MPL-2.0"
 
 [features]
 default = ["boot-vbuf-v0"]
+
+# Enable the root ring boot-time video buffer interface.
 boot-vbuf-v0 = ["dep:oro-boot-protocol"]
 
+# Allow IDs to be reused when they exhaust their version space.
+# Instead of turning into tombstones, they are made alive again and reused.
+# SAFETY(qix-): Enabling this feature may cause ABA issues in some cases.
+# SAFETY(qix-): Therefore, it is disabled by default.
+zombie-tombs = []
+
+# Debugs tombstones in the global table.
+# If enabled, tombstones will occur after 255 frees of a slot.
+debug-tombs = []
+
 [dependencies]
 oro-mem.workspace = true
 oro-macro.workspace = true
@@ -23,6 +35,7 @@ oro-debug.workspace = true
 oro-sync.workspace = true
 oro-sysabi.workspace = true
 oro-boot-protocol = { workspace = true, optional = true, features = ["utils"] }
+oro-dbgutil.workspace = true
 
 hashbrown.workspace = true
 

oro-kernel/src/lib.rs

@@ -17,6 +17,15 @@
 // SAFETY(qix-): Necessary to make the hashbrown crate wrapper work.
 // SAFETY(qix-): https://github.com/rust-lang/rust/issues/32838
 #![feature(allocator_api)]
+// SAFETY(qix-): Needed for the global table to initialize arrays of null pointers
+// SAFETY(qix-): safely, in order not to assume that `null == 0` (which is true on
+// SAFETY(qix-): most platforms, but is not specified anywhere). Technically we could
+// SAFETY(qix-): eschew this given that _we're the ones making a platform_ but it's still
+// SAFETY(qix-): a good idea to be explicit.
+#![feature(maybe_uninit_uninit_array)]
+// SAFETY(qix-): To be stabilized soon. Needed for the global table.
+// SAFETY(qix-): https://github.com/rust-lang/rust/issues/96097
+#![feature(maybe_uninit_array_assume_init)]
 #![cfg_attr(doc, feature(doc_cfg, doc_auto_cfg))]
 
 pub mod arch;
@@ -30,6 +39,7 @@ pub mod registry;
 pub mod ring;
 pub mod scheduler;
 pub mod sync;
+pub mod tab;
 pub mod table;
 pub mod thread;
 

oro-kernel/src/sync.rs

@@ -22,7 +22,7 @@ static HAS_SET_KERNEL_ID_FN: core::sync::atomic::AtomicBool =
 /// [`oro_sync::ReentrantLock`] implementation.
 #[doc(hidden)]
 #[no_mangle]
-unsafe extern "C" fn oro_sync_current_core_id() -> u32 {
+pub(crate) unsafe extern "C" fn oro_sync_current_core_id() -> u32 {
 	#[cfg(debug_assertions)]
 	{
 		assert!(