linux/arch/s390/Makefile
Heiko Carstens 80ddf5ce1c s390: always build relocatable kernel
Nathan Chancellor reported several link errors on s390 with
CONFIG_RELOCATABLE disabled, after binutils commit 906f69cf65da ("IBM
zSystems: Issue error for *DBL relocs on misaligned symbols"). The binutils
commit reveals potential miscompiles that might have happened already
before with linker script defined symbols at odd addresses.

A similar bug was recently fixed in the kernel with commit c9305b6c1f
("s390: fix nospec table alignments").

See https://github.com/ClangBuiltLinux/linux/issues/1747 for an analysis
from Ulich Weigand.

Therefore always build a relocatable kernel to avoid this problem. There is
hardly any use-case for non-relocatable kernels, so this shouldn't be
controversial.

Link: https://github.com/ClangBuiltLinux/linux/issues/1747
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20221030182202.2062705-1-hca@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2022-11-08 19:32:32 +01:00

178 lines
5.8 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# s390/Makefile
#
# This file is included by the global makefile so that you can add your own
# architecture-specific flags and dependencies.
#
# Copyright (C) 1994 by Linus Torvalds
#
LD_BFD := elf64-s390
KBUILD_LDFLAGS := -m elf64_s390
KBUILD_AFLAGS_MODULE += -fPIC
KBUILD_CFLAGS_MODULE += -fPIC
KBUILD_AFLAGS += -m64
KBUILD_CFLAGS += -m64
KBUILD_CFLAGS += -fPIE
LDFLAGS_vmlinux := -pie
aflags_dwarf := -Wa,-gdwarf-2
KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__
ifndef CONFIG_AS_IS_LLVM
KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf))
endif
KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack
KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY
KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbackchain
KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables
KBUILD_CFLAGS_DECOMPRESSOR += -ffreestanding
KBUILD_CFLAGS_DECOMPRESSOR += -fno-stack-protector
KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member)
KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g)
KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,))
KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_CC_NO_ARRAY_BOUNDS),-Wno-array-bounds)
UTS_MACHINE := s390x
STACK_SIZE := $(if $(CONFIG_KASAN),65536,16384)
CHECKFLAGS += -D__s390__ -D__s390x__
export LD_BFD
mflags-$(CONFIG_MARCH_Z10) := -march=z10
mflags-$(CONFIG_MARCH_Z196) := -march=z196
mflags-$(CONFIG_MARCH_ZEC12) := -march=zEC12
mflags-$(CONFIG_MARCH_Z13) := -march=z13
mflags-$(CONFIG_MARCH_Z14) := -march=z14
mflags-$(CONFIG_MARCH_Z15) := -march=z15
mflags-$(CONFIG_MARCH_Z16) := -march=z16
export CC_FLAGS_MARCH := $(mflags-y)
aflags-y += $(mflags-y)
cflags-y += $(mflags-y)
cflags-$(CONFIG_MARCH_Z10_TUNE) += -mtune=z10
cflags-$(CONFIG_MARCH_Z196_TUNE) += -mtune=z196
cflags-$(CONFIG_MARCH_ZEC12_TUNE) += -mtune=zEC12
cflags-$(CONFIG_MARCH_Z13_TUNE) += -mtune=z13
cflags-$(CONFIG_MARCH_Z14_TUNE) += -mtune=z14
cflags-$(CONFIG_MARCH_Z15_TUNE) += -mtune=z15
cflags-$(CONFIG_MARCH_Z16_TUNE) += -mtune=z16
cflags-y += -Wa,-I$(srctree)/arch/$(ARCH)/include
#
# Prevent tail-call optimizations, to get clearer backtraces:
#
cflags-$(CONFIG_FRAME_POINTER) += -fno-optimize-sibling-calls
KBUILD_AFLAGS_DECOMPRESSOR += $(aflags-y)
KBUILD_CFLAGS_DECOMPRESSOR += $(cflags-y)
ifneq ($(call cc-option,-mstack-size=8192 -mstack-guard=128),)
CC_FLAGS_CHECK_STACK := -mstack-size=$(STACK_SIZE)
ifeq ($(call cc-option,-mstack-size=8192),)
CC_FLAGS_CHECK_STACK += -mstack-guard=$(CONFIG_STACK_GUARD)
endif
export CC_FLAGS_CHECK_STACK
cflags-$(CONFIG_CHECK_STACK) += $(CC_FLAGS_CHECK_STACK)
endif
ifdef CONFIG_EXPOLINE
ifdef CONFIG_EXPOLINE_EXTERN
KBUILD_LDFLAGS_MODULE += arch/s390/lib/expoline/expoline.o
CC_FLAGS_EXPOLINE := -mindirect-branch=thunk-extern
CC_FLAGS_EXPOLINE += -mfunction-return=thunk-extern
else
CC_FLAGS_EXPOLINE := -mindirect-branch=thunk
CC_FLAGS_EXPOLINE += -mfunction-return=thunk
endif
CC_FLAGS_EXPOLINE += -mindirect-branch-table
export CC_FLAGS_EXPOLINE
cflags-y += $(CC_FLAGS_EXPOLINE) -DCC_USING_EXPOLINE
aflags-y += -DCC_USING_EXPOLINE
endif
ifdef CONFIG_FUNCTION_TRACER
ifeq ($(call cc-option,-mfentry -mnop-mcount),)
# make use of hotpatch feature if the compiler supports it
cc_hotpatch := -mhotpatch=0,3
ifneq ($(call cc-option,$(cc_hotpatch)),)
CC_FLAGS_FTRACE := $(cc_hotpatch)
KBUILD_AFLAGS += -DCC_USING_HOTPATCH
KBUILD_CFLAGS += -DCC_USING_HOTPATCH
endif
endif
endif
# Test CFI features of binutils
cfi := $(call as-instr,.cfi_startproc\n.cfi_val_offset 15$(comma)-160\n.cfi_endproc,-DCONFIG_AS_CFI_VAL_OFFSET=1)
KBUILD_CFLAGS += -mpacked-stack -mbackchain -msoft-float $(cflags-y)
KBUILD_CFLAGS += -pipe -Wno-sign-compare
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables $(cfi)
KBUILD_AFLAGS += $(aflags-y) $(cfi)
export KBUILD_AFLAGS_DECOMPRESSOR
export KBUILD_CFLAGS_DECOMPRESSOR
OBJCOPYFLAGS := -O binary
libs-y += arch/s390/lib/
drivers-y += drivers/s390/
boot := arch/s390/boot
syscalls := arch/s390/kernel/syscalls
tools := arch/s390/tools
all: bzImage
#KBUILD_IMAGE is necessary for packaging targets like rpm-pkg, deb-pkg...
KBUILD_IMAGE := $(boot)/bzImage
install:
$(call cmd,install)
bzImage: vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
zfcpdump:
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
vdso_install:
$(Q)$(MAKE) $(build)=arch/$(ARCH)/kernel/vdso64 $@
archheaders:
$(Q)$(MAKE) $(build)=$(syscalls) uapi
archprepare:
$(Q)$(MAKE) $(build)=$(syscalls) kapi
$(Q)$(MAKE) $(build)=$(tools) kapi
ifeq ($(KBUILD_EXTMOD),)
# We need to generate vdso-offsets.h before compiling certain files in kernel/.
# In order to do that, we should use the archprepare target, but we can't since
# asm-offsets.h is included in some files used to generate vdso-offsets.h, and
# asm-offsets.h is built in prepare0, for which archprepare is a dependency.
# Therefore we need to generate the header after prepare0 has been made, hence
# this hack.
prepare: vdso_prepare
vdso_prepare: prepare0
$(Q)$(MAKE) $(build)=arch/s390/kernel/vdso64 include/generated/vdso64-offsets.h
$(if $(CONFIG_COMPAT),$(Q)$(MAKE) \
$(build)=arch/s390/kernel/vdso32 include/generated/vdso32-offsets.h)
ifdef CONFIG_EXPOLINE_EXTERN
modules_prepare: expoline_prepare
expoline_prepare:
$(Q)$(MAKE) $(build)=arch/s390/lib/expoline arch/s390/lib/expoline/expoline.o
endif
endif
# Don't use tabs in echo arguments
define archhelp
echo '* bzImage - Kernel image for IPL ($(boot)/bzImage)'
echo ' install - Install kernel using'
echo ' (your) ~/bin/$(INSTALLKERNEL) or'
echo ' (distribution) /sbin/$(INSTALLKERNEL) or'
echo ' install to $$(INSTALL_PATH)'
endef