Index: arch/riscv/Makefile
--- arch/riscv/Makefile.orig
+++ arch/riscv/Makefile
@@ -24,7 +24,16 @@ ifeq ($(CONFIG_CMODEL_MEDANY),y)
 	CMODEL = medany
 endif
 
-ARCH_FLAGS = -march=$(ARCH_BASE)$(ARCH_A)$(ARCH_C) -mabi=$(ABI) \
+RISCV_MARCH = $(ARCH_BASE)$(ARCH_A)$(ARCH_C)
+
+# Newer binutils versions default to ISA spec version 20191213 which moves some
+# instructions from the I extension to the Zicsr and Zifencei extensions.
+toolchain-need-zicsr-zifencei := $(call cc-option-yn, -mabi=$(ABI) -march=$(RISCV_MARCH)_zicsr_zifencei)
+ifeq ($(toolchain-need-zicsr-zifencei),y)
+	RISCV_MARCH := $(RISCV_MARCH)_zicsr_zifencei
+endif
+
+ARCH_FLAGS = -march=$(RISCV_MARCH) -mabi=$(ABI) \
 	     -mcmodel=$(CMODEL)
 
 PLATFORM_CPPFLAGS	+= $(ARCH_FLAGS)
