diff --git a/src/northbridge/intel/gm45/ram_calc.c b/src/northbridge/intel/gm45/ram_calc.c
index c614082..719c59f 100644
--- a/src/northbridge/intel/gm45/ram_calc.c
+++ b/src/northbridge/intel/gm45/ram_calc.c
@@ -26,6 +26,7 @@
 #include <cpu/x86/mtrr.h>
 #include <cbmem.h>
 #include <program_loading.h>
+#include <stage_cache.h>
 #include <cpu/intel/smm/gen1/smi.h>
 #include "gm45.h"
 
@@ -123,6 +124,17 @@
 	return (void *) top_of_ram;
 }
 
+void stage_cache_external_region(void **base, size_t *size)
+{
+	/*
+	 * The ramstage cache lives in the TSEG region at RESERVED_SMM_OFFSET.
+	 * The top of RAM is defined to be the TSEG base address.
+	 */
+	*size = CONFIG_SMM_RESERVED_SIZE;
+	*base = (void *)(northbridge_get_tseg_base()
+			 + CONFIG_SMM_RESERVED_SIZE);
+}
+
 /* platform_enter_postcar() determines the stack to use after
  * cache-as-ram is torn down as well as the MTRR settings to use,
  * and continues execution in postcar stage. */