linux/arch/riscv/Makefile
Ben Dooks c1f6eff304
riscv: add as-options for modules with assembly compontents
When trying to load modules built for RISC-V which include assembly files
the kernel loader errors with "unexpected relocation type 'R_RISCV_ALIGN'"
due to R_RISCV_ALIGN relocations being generated by the assembler.

The R_RISCV_ALIGN relocations can be removed at the expense of code space
by adding -mno-relax to gcc and as.  In commit 7a8e7da422
("RISC-V: Fixes to module loading") -mno-relax is added to the build
variable KBUILD_CFLAGS_MODULE. See [1] for more info.

The issue is that when kbuild builds a .S file, it invokes gcc with
the -mno-relax flag, but this is not being passed through to the
assembler. Adding -Wa,-mno-relax to KBUILD_AFLAGS_MODULE ensures that
the assembler is invoked correctly. This may have now been fixed in
gcc[2] and this addition should not stop newer gcc and as from working.

[1] https://github.com/riscv/riscv-elf-psabi-doc/issues/183
[2] 3b0a7d624e

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Link: https://lore.kernel.org/r/20220529152200.609809-1-ben.dooks@codethink.co.uk
Fixes: ab1ef68e54 ("RISC-V: Add sections of PLT and GOT for kernel module")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-07-21 12:09:29 -07:00

163 lines
4.6 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.
#
OBJCOPYFLAGS := -O binary
LDFLAGS_vmlinux :=
ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
LDFLAGS_vmlinux := --no-relax
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
CC_FLAGS_FTRACE := -fpatchable-function-entry=8
endif
ifeq ($(CONFIG_CMODEL_MEDLOW),y)
KBUILD_CFLAGS_MODULE += -mcmodel=medany
endif
export BITS
ifeq ($(CONFIG_ARCH_RV64I),y)
BITS := 64
UTS_MACHINE := riscv64
KBUILD_CFLAGS += -mabi=lp64
KBUILD_AFLAGS += -mabi=lp64
KBUILD_LDFLAGS += -melf64lriscv
else
BITS := 32
UTS_MACHINE := riscv32
KBUILD_CFLAGS += -mabi=ilp32
KBUILD_AFLAGS += -mabi=ilp32
KBUILD_LDFLAGS += -melf32lriscv
endif
ifeq ($(CONFIG_LD_IS_LLD),y)
KBUILD_CFLAGS += -mno-relax
KBUILD_AFLAGS += -mno-relax
ifndef CONFIG_AS_IS_LLVM
KBUILD_CFLAGS += -Wa,-mno-relax
KBUILD_AFLAGS += -Wa,-mno-relax
endif
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
# 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 := $(call cc-option-yn, -march=$(riscv-march-y)_zicsr_zifencei)
riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei
KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
KBUILD_AFLAGS += -march=$(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 ($(CONFIG_CMODEL_MEDANY),y)
KBUILD_CFLAGS += -mcmodel=medany
endif
ifeq ($(CONFIG_PERF_EVENTS),y)
KBUILD_CFLAGS += -fno-omit-frame-pointer
endif
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.
KBUILD_CFLAGS += $(call cc-option,-mstrict-align)
ifeq ($(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
KBUILD_IMAGE := $(boot)/Image.gz
endif
head-y := arch/riscv/kernel/head.o
libs-y += arch/riscv/lib/
libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
PHONY += vdso_install
vdso_install:
$(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso $@
$(if $(CONFIG_COMPAT),$(Q)$(MAKE) \
$(build)=arch/riscv/kernel/compat_vdso $@)
ifeq ($(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) \
$(build)=arch/riscv/kernel/compat_vdso include/generated/compat_vdso-offsets.h)
endif
endif
ifneq ($(CONFIG_XIP_KERNEL),y)
ifeq ($(CONFIG_RISCV_M_MODE)$(CONFIG_SOC_CANAAN),yy)
KBUILD_IMAGE := $(boot)/loader.bin
else
KBUILD_IMAGE := $(boot)/Image.gz
endif
endif
BOOT_TARGETS := Image Image.gz loader loader.bin xipImage
all: $(notdir $(KBUILD_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