diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index af8854f9eae3c8..3caee570e79bf8 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -989,10 +989,12 @@ unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
 	 * linux,drconf-usable-memory properties. Get an approximate on the
 	 * number of usable memory entries and use for FDT size estimation.
 	 */
-	usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) +
-		       (2 * (resource_size(&crashk_res) / drmem_lmb_size())));
-
-	extra_size = (unsigned int)(usm_entries * sizeof(u64));
+	if (drmem_lmb_size()) {
+		usm_entries = ((memblock_end_of_DRAM() / drmem_lmb_size()) +
+			       (2 * (resource_size(&crashk_res) / drmem_lmb_size())));
+		extra_size = (unsigned int)(usm_entries * sizeof(u64));
+	} else
+		extra_size = 0;
 
 	/*
 	 * Get the number of CPU nodes in the current DT. This allows to