[U-Boot] [PATCH 07/30] riscv: set -march and -mabi based on the Kconfig configuration

[Lukas Auer]

Use the new Kconfig entries to construct the ISA string for the -march
compiler flag. The -mabi compiler flag is selected based on the base
integer instruction set.

With this change, the C (compressed instructions) ISA extension is now
enabled for all boards with CONFIG_RISCV_ISA_C set. Buildman reports a
decrease in binary size of 71590 bytes.

Signed-off-by: Lukas Auer <lukas.auer at aisec.fraunhofer.de>
---

 arch/riscv/Makefile  | 13 +++++++++++++
 arch/riscv/config.mk |  4 ----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 8fb6a889d8..6fb292d0b4 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -3,6 +3,19 @@
 # Copyright (C) 2017 Andes Technology Corporation.
 # Rick Chen, Andes Technology Corporation <rick at andestech.com>
 
+riscv-march-$(CONFIG_ARCH_RV32I)	:= rv32im
+riscv-march-$(CONFIG_ARCH_RV64I)	:= rv64im
+riscv-march-$(CONFIG_RISCV_ISA_A)	:= $(riscv-march-y)a
+riscv-march-$(CONFIG_RISCV_ISA_C)	:= $(riscv-march-y)c
+
+riscv-mabi-$(CONFIG_ARCH_RV64I)	:= lp64
+riscv-mabi-$(CONFIG_ARCH_RV32I)	:= ilp32
+
+arch-y := -march=$(riscv-march-y) -mabi=$(riscv-mabi-y)
+
+PLATFORM_CPPFLAGS	+= $(arch-y)
+CFLAGS_EFI		+= $(arch-y)
+
 head-y := arch/riscv/cpu/start.o
 
 libs-y += arch/riscv/cpu/
diff --git a/arch/riscv/config.mk b/arch/riscv/config.mk
index ed9eb0c24c..9088b9ef2c 100644
--- a/arch/riscv/config.mk
+++ b/arch/riscv/config.mk
@@ -14,16 +14,12 @@
 64bit-emul		:= elf64lriscv
 
 ifdef CONFIG_32BIT
-PLATFORM_CPPFLAGS	+= -march=rv32ima -mabi=ilp32
 PLATFORM_LDFLAGS	+= -m $(32bit-emul)
-CFLAGS_EFI		+= -march=rv32ima -mabi=ilp32
 EFI_LDS			:= elf_riscv32_efi.lds
 endif
 
 ifdef CONFIG_64BIT
-PLATFORM_CPPFLAGS	+= -march=rv64ima -mabi=lp64
 PLATFORM_LDFLAGS	+= -m $(64bit-emul)
-CFLAGS_EFI		+= -march=rv64ima -mabi=lp64
 EFI_LDS			:= elf_riscv64_efi.lds
 endif
 
-- 
2.17.2