reclaiming uefi memory

src/root.zig

@@ -41,13 +41,14 @@ pub const page_size = 4096;
 /// native memory description into these kinds, so the kernel never learns what
 /// booted it. [[arch]] keeps the same discipline for CPU code.
 pub const MemoryKind = enum(u32) {
-    /// Free RAM the kernel may allocate.
+    /// Free RAM the kernel may allocate. Each boot path folds its own transient
+    /// memory into this once it's genuinely free (e.g. the UEFI loader classifies
+    /// boot-services memory as usable after ExitBootServices), so the kernel never
+    /// has to know about boot-protocol-specific "reclaimable" states.
     usable,
-    /// Firmware, MMIO, the kernel image, our own boot buffers — never hand out.
+    /// Firmware, MMIO, the kernel image, our own boot buffers, the boot stack —
+    /// never hand out.
     reserved,
-    /// Usable once the kernel is done with boot-time structures (e.g. UEFI boot
-    /// services memory, which is free after ExitBootServices).
-    reclaimable,
     /// ACPI tables: parse, then reclaim.
     acpi_tables,
     /// ACPI non-volatile storage: preserve across sleep, do not allocate.