diff --git a/src/arch/x86/boot/acpigen.c b/src/arch/x86/boot/acpigen.c
index 7dc7fed3a7..6d2832ce2d 100644
--- a/src/arch/x86/boot/acpigen.c
+++ b/src/arch/x86/boot/acpigen.c
@@ -35,7 +35,7 @@ static char *gencurrent;
 char *len_stack[ACPIGEN_LENSTACK_SIZE];
 int ltop = 0;
 
-static int acpigen_write_len_f(void)
+int acpigen_write_len_f(void)
 {
 	ASSERT(ltop < (ACPIGEN_LENSTACK_SIZE - 1))
 	    len_stack[ltop++] = gencurrent;
diff --git a/src/arch/x86/include/arch/acpigen.h b/src/arch/x86/include/arch/acpigen.h
index 9dc9675bd6..8b5513ce5e 100644
--- a/src/arch/x86/include/arch/acpigen.h
+++ b/src/arch/x86/include/arch/acpigen.h
@@ -35,6 +35,7 @@ struct cst_entry {
 	int power;
 };
 
+int acpigen_write_len_f(void);
 void acpigen_patch_len(int len);
 void acpigen_set_current(char *curr);
 char *acpigen_get_current(void);