[PATCH 2/3] riscv: Factor out riscv-march-y to a separate Makefile

[Samuel Holland]

Since it is not possible to incrementally add/remove extensions from the
compiler's ISA string by appending arguments, any code that wants to
modify the ISA string must recreate the whole thing. To support this,
factor out the logic for generating the -march argument so it can be
reused where needed.

Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
---

 arch/riscv/Makefile     | 12 +-----------
 arch/riscv/Makefile.isa | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 11 deletions(-)
 create mode 100644 arch/riscv/Makefile.isa

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index a74be78678eb..c738eafe67a0 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -58,22 +58,12 @@ ifeq ($(CONFIG_SHADOW_CALL_STACK),y)
 	KBUILD_LDFLAGS += --no-relax-gp
 endif
 
-# ISA string setting
-riscv-march-$(CONFIG_ARCH_RV32I)	:= rv32ima
-riscv-march-$(CONFIG_ARCH_RV64I)	:= rv64ima
-riscv-march-$(CONFIG_FPU)		:= $(riscv-march-y)fd
-riscv-march-$(CONFIG_RISCV_ISA_C)	:= $(riscv-march-y)c
-riscv-march-$(CONFIG_RISCV_ISA_V)	:= $(riscv-march-y)v
-
 ifdef CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC
 KBUILD_CFLAGS += -Wa,-misa-spec=2.2
 KBUILD_AFLAGS += -Wa,-misa-spec=2.2
-else
-riscv-march-$(CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI) := $(riscv-march-y)_zicsr_zifencei
 endif
 
-# Check if the toolchain supports Zihintpause extension
-riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE) := $(riscv-march-y)_zihintpause
+include $(srctree)/arch/riscv/Makefile.isa
 
 # Remove F,D,V from isa string for all. Keep extensions between "fd" and "v" by
 # matching non-v and non-multi-letter extensions out with the filter ([^v_]*)
diff --git a/arch/riscv/Makefile.isa b/arch/riscv/Makefile.isa
new file mode 100644
index 000000000000..e10c77e26fe6
--- /dev/null
+++ b/arch/riscv/Makefile.isa
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# ISA string setting
+riscv-march-$(CONFIG_ARCH_RV32I)	:= rv32ima
+riscv-march-$(CONFIG_ARCH_RV64I)	:= rv64ima
+riscv-march-$(CONFIG_FPU)		:= $(riscv-march-y)fd
+riscv-march-$(CONFIG_RISCV_ISA_C)	:= $(riscv-march-y)c
+riscv-march-$(CONFIG_RISCV_ISA_V)	:= $(riscv-march-y)v
+
+ifndef CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC
+riscv-march-$(CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI) := $(riscv-march-y)_zicsr_zifencei
+endif
+
+# Check if the toolchain supports Zihintpause extension
+riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE) := $(riscv-march-y)_zihintpause
-- 
2.42.0