diff --git a/js/src/nanojit/VMPI.cpp b/js/src/nanojit/VMPI.cpp
index 893deb04de7d..68aa8828b8b1 100644
--- a/js/src/nanojit/VMPI.cpp
+++ b/js/src/nanojit/VMPI.cpp
@@ -42,6 +42,12 @@
 
 using namespace avmplus;
 
+size_t
+VMPI_getVMPageSize()
+{
+    return 4096;
+}
+
 #ifdef WIN32
 void
 VMPI_setPageProtection(void *address,
diff --git a/js/src/nanojit/VMPI.h b/js/src/nanojit/VMPI.h
index 4938dfcf3e7c..429ed11e1602 100644
--- a/js/src/nanojit/VMPI.h
+++ b/js/src/nanojit/VMPI.h
@@ -95,6 +95,8 @@ typedef unsigned __int64 uint64_t;
 #define VMPI_isdigit isdigit
 #define VMPI_getDate()
 
+extern size_t VMPI_getVMPageSize();
+
 extern void VMPI_setPageProtection(void *address,
                                    size_t size,
                                    bool executableFlag,