Implement lock IRQ nesting via stack variables/contexts

kernel/mm/liballoc.h

@@ -47,7 +47,7 @@ struct boundary_tag {
  * \return 0 if the lock was acquired successfully. Anything else is
  * failure.
  */
-extern int liballoc_lock ();
+extern int liballoc_lock (void* ctx);
 
 /** This function unlocks what was previously locked by the liballoc_lock
  * function.  If it disabled interrupts, it enables interrupts. If it
@@ -55,7 +55,7 @@ extern int liballoc_lock ();
  *
  * \return 0 if the lock was successfully released.
  */
-extern int liballoc_unlock ();
+extern int liballoc_unlock (void* ctx);
 
 /** This is the hook into the local system which allocates pages. It
  * accepts an integer parameter which is the number of pages