linux/arch/riscv/Makefile
Miguel Ojeda 70a57b2472
RISC-V: enable building 64-bit kernels with rust support
The rust modules work on 64-bit RISC-V, with no twiddling required.
Select HAVE_RUST and provide the required flags to kbuild so that the
modules can be used. The Makefile and Kconfig changes are lifted from
work done by Miguel in the Rust-for-Linux tree, hence his authorship.
Following the rabbit hole, the Makefile changes originated in a script,
created based on config files originally added by Gary, hence his
co-authorship.

32-bit is broken in core rust code, so support is limited to 64-bit:
ld.lld: error: undefined symbol: __udivdi3

As 64-bit RISC-V is now supported, add it to the arch support table.

Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Co-developed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240409-silencer-book-ce1320f06aab@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-04-28 14:50:34 -07:00

206 lines
6.3 KiB
Makefile

# This file is included by the global makefile so that you can add your own
# architecture-specific flags and dependencies.
#
# This file is subject to the terms and conditions of the GNU General Public
# License. See the file "COPYING" in the main directory of this archive
# for more details.
#
LDFLAGS_vmlinux := -z norelro
ifeq ($(CONFIG_RELOCATABLE),y)
LDFLAGS_vmlinux += -shared -Bsymbolic -z notext --emit-relocs
KBUILD_CFLAGS += -fPIE
endif
ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
LDFLAGS_vmlinux += --no-relax
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
ifeq ($(CONFIG_RISCV_ISA_C),y)
CC_FLAGS_FTRACE := -fpatchable-function-entry=4
else
CC_FLAGS_FTRACE := -fpatchable-function-entry=2
endif
endif
ifeq ($(CONFIG_CMODEL_MEDLOW),y)
KBUILD_CFLAGS_MODULE += -mcmodel=medany
endif
export BITS
ifeq ($(CONFIG_ARCH_RV64I),y)
BITS := 64
UTS_MACHINE := riscv64
KBUILD_CFLAGS += -mabi=lp64
KBUILD_AFLAGS += -mabi=lp64
KBUILD_LDFLAGS += -melf64lriscv
KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv64 --target=riscv64imac-unknown-none-elf \
-Cno-redzone
else
BITS := 32
UTS_MACHINE := riscv32
KBUILD_CFLAGS += -mabi=ilp32
KBUILD_AFLAGS += -mabi=ilp32
KBUILD_LDFLAGS += -melf32lriscv
endif
ifndef CONFIG_RISCV_USE_LINKER_RELAXATION
KBUILD_CFLAGS += -mno-relax
KBUILD_AFLAGS += -mno-relax
ifndef CONFIG_AS_IS_LLVM
KBUILD_CFLAGS += -Wa,-mno-relax
KBUILD_AFLAGS += -Wa,-mno-relax
endif
# LLVM has an issue with target-features and LTO: https://github.com/llvm/llvm-project/issues/59350
# Ensure it is aware of linker relaxation with LTO, otherwise relocations may
# be incorrect: https://github.com/llvm/llvm-project/issues/65090
else ifeq ($(CONFIG_LTO_CLANG),y)
KBUILD_LDFLAGS += -mllvm -mattr=+c -mllvm -mattr=+relax
endif
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) := $(riscv-march-y)v
ifneq ($(CONFIG_RISCV_ISA_C),y)
KBUILD_RUSTFLAGS += -Ctarget-feature=-c
endif
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) := $(riscv-march-y)_zihintpause
# Remove F,D,V from isa string for all. Keep extensions between "fd" and "v" by
# matching non-v and non-multi-letter extensions out with the filter ([^v_]*)
KBUILD_CFLAGS += -march=$(shell echo $(riscv-march-y) | sed -E 's/(rv32ima|rv64ima)fd([^v_]*)v?/\1\2/')
KBUILD_AFLAGS += -march=$(riscv-march-y)
KBUILD_CFLAGS += -mno-save-restore
KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
ifeq ($(CONFIG_CMODEL_MEDLOW),y)
KBUILD_CFLAGS += -mcmodel=medlow
endif
ifeq ($(CONFIG_CMODEL_MEDANY),y)
KBUILD_CFLAGS += -mcmodel=medany
endif
# Avoid generating .eh_frame sections.
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables
# The RISC-V attributes frequently cause compatibility issues and provide no
# information, so just turn them off.
KBUILD_CFLAGS += $(call cc-option,-mno-riscv-attribute)
KBUILD_AFLAGS += $(call cc-option,-mno-riscv-attribute)
KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mno-arch-attr)
KBUILD_AFLAGS += $(call as-option,-Wa$(comma)-mno-arch-attr)
KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax)
KBUILD_AFLAGS_MODULE += $(call as-option,-Wa$(comma)-mno-relax)
# GCC versions that support the "-mstrict-align" option default to allowing
# unaligned accesses. While unaligned accesses are explicitly allowed in the
# RISC-V ISA, they're emulated by machine mode traps on all extant
# architectures. It's faster to have GCC emit only aligned accesses.
ifneq ($(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS),y)
KBUILD_CFLAGS += $(call cc-option,-mstrict-align)
endif
ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
prepare: stack_protector_prepare
stack_protector_prepare: prepare0
$(eval KBUILD_CFLAGS += -mstack-protector-guard=tls \
-mstack-protector-guard-reg=tp \
-mstack-protector-guard-offset=$(shell \
awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}' \
include/generated/asm-offsets.h))
endif
# arch specific predefines for sparse
CHECKFLAGS += -D__riscv -D__riscv_xlen=$(BITS)
# Default target when executing plain make
boot := arch/riscv/boot
ifeq ($(CONFIG_XIP_KERNEL),y)
KBUILD_IMAGE := $(boot)/xipImage
else
ifeq ($(CONFIG_RISCV_M_MODE)$(CONFIG_ARCH_CANAAN),yy)
KBUILD_IMAGE := $(boot)/loader.bin
else
ifeq ($(CONFIG_EFI_ZBOOT),)
KBUILD_IMAGE := $(boot)/Image.gz
else
KBUILD_IMAGE := $(boot)/vmlinuz.efi
endif
endif
endif
libs-y += arch/riscv/lib/
libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
ifeq ($(KBUILD_EXTMOD),)
ifeq ($(CONFIG_MMU),y)
prepare: vdso_prepare
vdso_prepare: prepare0
$(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso include/generated/vdso-offsets.h
$(if $(CONFIG_COMPAT),$(Q)$(MAKE) \
$(build)=arch/riscv/kernel/compat_vdso include/generated/compat_vdso-offsets.h)
endif
endif
vdso-install-y += arch/riscv/kernel/vdso/vdso.so.dbg
vdso-install-$(CONFIG_COMPAT) += arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg:../compat_vdso/compat_vdso.so
BOOT_TARGETS := Image Image.gz loader loader.bin xipImage vmlinuz.efi
all: $(notdir $(KBUILD_IMAGE))
loader.bin: loader
Image.gz loader vmlinuz.efi: Image
$(BOOT_TARGETS): vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
@$(kecho) ' Kernel: $(boot)/$@ is ready'
Image.%: Image
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
install: KBUILD_IMAGE := $(boot)/Image
zinstall: KBUILD_IMAGE := $(boot)/Image.gz
install zinstall:
$(call cmd,install)
PHONY += rv32_randconfig
rv32_randconfig:
$(Q)$(MAKE) KCONFIG_ALLCONFIG=$(srctree)/arch/riscv/configs/32-bit.config \
-f $(srctree)/Makefile randconfig
PHONY += rv64_randconfig
rv64_randconfig:
$(Q)$(MAKE) KCONFIG_ALLCONFIG=$(srctree)/arch/riscv/configs/64-bit.config \
-f $(srctree)/Makefile randconfig
PHONY += rv32_defconfig
rv32_defconfig:
$(Q)$(MAKE) -f $(srctree)/Makefile defconfig 32-bit.config
PHONY += rv32_nommu_virt_defconfig
rv32_nommu_virt_defconfig:
$(Q)$(MAKE) -f $(srctree)/Makefile nommu_virt_defconfig 32-bit.config