Call global constructors during initialization

This might be a mistake because we can't control the order of global construction, but we already have several global constructors that were simply not being called before. As long as we keep all global constructors simple, this should be okay.

Call global constructors during initialization
8e60785f · Austin Clements · Silas Boyd-Wickizer · 28ead2d3 · 8e60785f · 8e60785f
--- a/kernel/kernel.ld
+++ b/kernel/kernel.ld
@@ -18,6 +18,14 @@ SECTIONS
 		*(.prof)
 	}
 	PROVIDE(eprof = .);
+
+	PROVIDE(sctors = .);
+	.ctors : {
+		KEEP(*(SORT(.ctors.*)));
+		KEEP(*(.ctors));
+	}
+	PROVIDE(ectors = .);
+
 	. = ALIGN(0x1000);
 	.data : {
 		*(.data .data.* .gnu.linkonce.d.*)

--- a/kernel/main.cc
+++ b/kernel/main.cc
@@ -133,6 +133,11 @@ cmain(u64 mbmagic, u64 mbaddr)
 {
  extern u64 cpuhz;

+  // Call global constructors
+  extern const uptr sctors[], ectors[];
+  for (const uptr *ctorva = ectors; ctorva > sctors; )
+    ((void(*)()) *--ctorva)();
+
  initpg();
  inithz();        // CPU Hz, microdelay
  initpic();       // interrupt controller