diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 08946de..54be925 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -2,6 +2,38 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+# This selects which instruction set is used.
+arch-$(CONFIG_CPU_ARM720T)	=-march=armv4
+arch-$(CONFIG_CPU_ARM920T)	=-march=armv4
+arch-$(CONFIG_CPU_ARM926EJS)	=-march=armv5te
+arch-$(CONFIG_CPU_ARM946ES)	=-march=armv4
+arch-$(CONFIG_CPU_SA1100)	=-march=armv4
+arch-$(CONFIG_CPU_PXA)		=
+arch-$(CONFIG_CPU_ARM1136)	=-march=armv5
+arch-$(CONFIG_CPU_ARM1176)	=-march=armv5t
+arch-$(CONFIG_CPU_V7)		=$(call cc-option, -march=armv7-a, -march=armv5)
+arch-$(CONFIG_ARM64)		=-march=armv8-a
+
+# Evaluate arch cc-option calls now
+arch-y := $(arch-y)
+
+# This selects how we optimise for the processor.
+tune-$(CONFIG_CPU_ARM720T)	=-mtune=arm7tdmi
+tune-$(CONFIG_CPU_ARM920T)	=
+tune-$(CONFIG_CPU_ARM926EJS)	=
+tune-$(CONFIG_CPU_ARM946ES)	=
+tune-$(CONFIG_CPU_SA1100)	=-mtune=strongarm1100
+tune-$(CONFIG_CPU_PXA)		=-mcpu=xscale
+tune-$(CONFIG_CPU_ARM1136)	=
+tune-$(CONFIG_CPU_ARM1176)	=
+tune-$(CONFIG_CPU_V7)		=
+tune-$(CONFIG_ARM64)		=
+
+# Evaluate tune cc-option calls now
+tune-y := $(tune-y)
+
+PLATFORM_CPPFLAGS += $(arch-y) $(tune-y)
+
 # Machine directory name.  This list is sorted alphanumerically
 # by CONFIG_* macro name.
 machine-$(CONFIG_ARCH_AT91)		+= at91