Make use of mspaces

src/start.rs

@@ -67,7 +67,26 @@ static INIT_ARRAY: [extern "C" fn(); 1] = [init_array];
 
 static mut init_complete: bool = false;
 
+fn alloc_init() {
+    unsafe{
+        if let Some(tcb) = ld_so::tcb::Tcb::current() {
+            if tcb.mspace != 0 {
+                ALLOCATOR.set_book_keeper(tcb.mspace);
+            } else if ALLOCATOR.get_book_keeper() == 0 {
+                ALLOCATOR.set_book_keeper(new_mspace());
+            }
+        } else if ALLOCATOR.get_book_keeper() == 0 {
+            ALLOCATOR.set_book_keeper(new_mspace());
+        }
+    }
+}
+
 extern "C" fn init_array() {
+    // The thing is that we cannot guarantee if
+    // init_array runs first or if relibc_start runs first
+    // Still whoever gets to run first must initialize rust
+    // memory allocator before doing anything else.
+    alloc_init();
     io_init();
     unsafe { init_complete = true };
 }
@@ -95,11 +114,7 @@ pub unsafe extern "C" fn relibc_start(sp: &'static Stack) -> ! {
     }
     // Step 1 setup the right allocator...
     // if any memory rust based memory allocation happen before this step .. we are doomed.
-    if let Some(tcb) = ld_so::tcb::Tcb::current() {
-        ALLOCATOR.set_book_keeper(tcb.mspace);
-    } else {
-        ALLOCATOR.set_book_keeper(new_mspace());
-    }
+    alloc_init();
 
     // Ensure correct host system before executing more system calls
     relibc_verify_host();