--- zzzz-none-000/linux-4.1.52/arch/arm/mm/flush.c	2018-05-28 02:26:45.000000000 +0000
+++ bcm63-7530ax-731/linux-4.1.52/arch/arm/mm/flush.c	2022-03-02 11:37:12.000000000 +0000
@@ -21,6 +21,21 @@
 
 #include "mm.h"
 
+#if defined(CONFIG_BCM_KF_SPECTRE_PATCH) && defined(CONFIG_BCM_SPECTRE_PATCH_ENABLE)
+#ifdef CONFIG_ARM_HEAVY_MB
+void arm_heavy_mb(void)
+{
+#ifdef CONFIG_OUTER_CACHE_SYNC
+	if (outer_cache.sync)
+		outer_cache.sync();
+#endif
+}
+#else
+void arm_heavy_mb(void) {}
+#endif
+EXPORT_SYMBOL(arm_heavy_mb);
+#endif /* CONFIG_BCM_KF_SPECTRE_PATCH && CONFIG_BCM_SPECTRE_PATCH_ENABLE */
+
 #ifdef CONFIG_CPU_CACHE_VIPT
 
 static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)