Files
buildroot/arch/arch.mk.riscv
Charlie Jenkins 166bfd3e66 arch: riscv: Add RISCV_ISA_EXTRA config string
Adds a new user-configurable string to arch/Config.in.riscv, and in
arch/arch.mk.riscv appends it to GCC_TARGET_ARCH.

This enables custom extensions/combinations to be easily configured.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Jesse Taube <Mr.Bossman075@gmail.com>
[Arnout:
 - fix check-package warnings
 - introduce ARCH_RISV_ISA_EXTRA to simplify stripping of quotes
]
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
2026-02-04 11:11:43 +01:00

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#
# Configure the GCC_TARGET_ARCH variable and append the
# appropriate RISC-V ISA extensions.
#
ifeq ($(BR2_riscv),y)
ifeq ($(BR2_RISCV_64),y)
GCC_TARGET_ARCH := rv64i
else
GCC_TARGET_ARCH := rv32i
endif
ifeq ($(BR2_RISCV_ISA_RVM),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)m
endif
ifeq ($(BR2_RISCV_ISA_RVA),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)a
endif
ifeq ($(BR2_RISCV_ISA_RVF),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)f
endif
ifeq ($(BR2_RISCV_ISA_RVD),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)d
endif
ifeq ($(BR2_RISCV_ISA_RVC),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)c
endif
ifeq ($(BR2_RISCV_ISA_RVV),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)v
endif
# Starting from gcc 12.x, csr and fence instructions have been
# separated from the base I instruction set, and special -march
# suffixes are needed to enable their support. In Buildroot, we assume
# all RISC-V cores that support Linux implement those instructions, so
# we unconditionally enable those extensions.
ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_12),y)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)_zicsr_zifencei
endif
ARCH_RISV_ISA_EXTRA = $(call qstrip, $(BR2_RISCV_ISA_EXTRA))
ifneq ($(ARCH_RISV_ISA_EXTRA),)
GCC_TARGET_ARCH := $(GCC_TARGET_ARCH)_$(ARCH_RISV_ISA_EXTRA)
endif
endif