From: Alexandre Ghiti alexandre.ghiti@canonical.com
The following description is copied from the equivalent patch for the Linux Kernel proposed by Aurelien Jarno:
From version 2.38, binutils default to ISA spec version 20191213. This
means that the csr read/write (csrr*/csrw*) instructions and fence.i instruction has separated from the `I` extension, become two standalone extensions: Zicsr and Zifencei. As the kernel uses those instruction, this causes the following build failure:
arch/riscv/cpu/mtrap.S: Assembler messages: arch/riscv/cpu/mtrap.S:65: Error: unrecognized opcode `csrr a0,scause' arch/riscv/cpu/mtrap.S:66: Error: unrecognized opcode `csrr a1,sepc' arch/riscv/cpu/mtrap.S:67: Error: unrecognized opcode `csrr a2,stval' arch/riscv/cpu/mtrap.S:70: Error: unrecognized opcode `csrw sepc,a0'
Signed-off-by: Alexandre Ghiti alexandre.ghiti@canonical.com Reviewed-by: Bin Meng bmeng.cn@gmail.com Tested-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com Tested-by: Heiko Stuebner heiko@sntech.de Tested-by: Christian Stewart christian@paral.in --- v2: no change --- arch/riscv/Makefile | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 0b80eb8d86..53d1194ffb 100644 --- a/arch/riscv/Makefile +++ b/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)