rt: Move more setup code into create_stack

Author: brson

src/rt/rust_stack.h

@@ -17,7 +17,10 @@ template <class T>
 stk_seg *
 create_stack(T allocer, size_t sz) {
   size_t total_sz = sizeof(stk_seg) + sz;
-  return (stk_seg *)allocer->malloc(total_sz, "stack");
+  stk_seg *stk = (stk_seg *)allocer->malloc(total_sz, "stack");
+  memset(stk, 0, sizeof(stk_seg));
+  stk->end = (uintptr_t) &stk->data[sz];
+  return stk;
 }
 
 template <class T>

src/rt/rust_task.cpp

@@ -584,11 +584,9 @@ rust_task::new_stack(size_t requested_sz) {
     size_t sz = rust_stk_sz + RED_ZONE_SIZE;
     stk_seg *new_stk = create_stack(this, sz);
     LOGPTR(thread, "new stk", (uintptr_t)new_stk);
-    memset(new_stk, 0, sizeof(stk_seg));
     add_stack_canary(new_stk);
     new_stk->prev = NULL;
     new_stk->next = stk;
-    new_stk->end = (uintptr_t) &new_stk->data[rust_stk_sz + RED_ZONE_SIZE];
     LOGPTR(thread, "stk end", new_stk->end);
 
     stk = new_stk;