56769ba4b2
Currently, there is no standard implementation for vdso_install,
leading to various issues:
1. Code duplication
Many architectures duplicate similar code just for copying files
to the install destination.
Some architectures (arm, sparc, x86) create build-id symlinks,
introducing more code duplication.
2. Unintended updates of in-tree build artifacts
The vdso_install rule depends on the vdso files to install.
It may update in-tree build artifacts. This can be problematic,
as explained in commit 19514fc665ff ("arm, kbuild: make
"make install" not depend on vmlinux").
3. Broken code in some architectures
Makefile code is often copied from one architecture to another
without proper adaptation.
'make vdso_install' for parisc does not work.
'make vdso_install' for s390 installs vdso64, but not vdso32.
To address these problems, this commit introduces a generic vdso_install
rule.
Architectures that support vdso_install need to define vdso-install-y
in arch/*/Makefile. vdso-install-y lists the files to install.
For example, arch/x86/Makefile looks like this:
vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg
vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg
vdso-install-$(CONFIG_X86_32) += arch/x86/entry/vdso/vdso32.so.dbg
vdso-install-$(CONFIG_IA32_EMULATION) += arch/x86/entry/vdso/vdso32.so.dbg
These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix,
if exists, stripped away.
vdso-install-y can optionally take the second field after the colon
separator. This is needed because some architectures install a vdso
file as a different base name.
The following is a snippet from arch/arm64/Makefile.
vdso-install-$(CONFIG_COMPAT_VDSO) += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so
This will rename vdso.so.dbg to vdso32.so during installation. If such
architectures change their implementation so that the base names match,
this workaround will go away.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Guo Ren <guoren@kernel.org>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
86 lines
2.3 KiB
Makefile
86 lines
2.3 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Objects to go into the VDSO.
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KASAN_SANITIZE := n
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KCOV_INSTRUMENT := n
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# Include the generic Makefile to check the built vdso.
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include $(srctree)/lib/vdso/Makefile
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obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o sigreturn.o
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# Common compiler flags between ABIs.
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ccflags-vdso := \
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$(filter -I%,$(KBUILD_CFLAGS)) \
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$(filter -E%,$(KBUILD_CFLAGS)) \
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$(filter -march=%,$(KBUILD_CFLAGS)) \
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$(filter -m%-float,$(KBUILD_CFLAGS)) \
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$(CLANG_FLAGS) \
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-D__VDSO__
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cflags-vdso := $(ccflags-vdso) \
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-isystem $(shell $(CC) -print-file-name=include) \
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$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
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-O2 -g -fno-strict-aliasing -fno-common -fno-builtin \
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-fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \
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$(call cc-option, -fno-asynchronous-unwind-tables) \
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$(call cc-option, -fno-stack-protector)
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aflags-vdso := $(ccflags-vdso) \
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-D__ASSEMBLY__ -Wa,-gdwarf-2
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ifneq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
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endif
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# VDSO linker flags.
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ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
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$(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \
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--hash-style=sysv --build-id -T
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GCOV_PROFILE := n
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#
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# Shared build commands.
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#
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quiet_cmd_vdsold_and_vdso_check = LD $@
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cmd_vdsold_and_vdso_check = $(cmd_ld); $(cmd_vdso_check)
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quiet_cmd_vdsoas_o_S = AS $@
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cmd_vdsoas_o_S = $(CC) $(a_flags) -c -o $@ $<
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# Generate VDSO offsets using helper script
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gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
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quiet_cmd_vdsosym = VDSOSYM $@
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cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
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include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
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$(call if_changed,vdsosym)
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#
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# Build native VDSO.
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#
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native-abi := $(filter -mabi=%,$(KBUILD_CFLAGS))
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targets += $(obj-vdso-y)
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targets += vdso.lds vdso.so.dbg vdso.so
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obj-vdso := $(obj-vdso-y:%.o=$(obj)/%.o)
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$(obj-vdso): KBUILD_CFLAGS := $(cflags-vdso) $(native-abi)
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$(obj-vdso): KBUILD_AFLAGS := $(aflags-vdso) $(native-abi)
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$(obj)/vdso.lds: KBUILD_CPPFLAGS := $(ccflags-vdso) $(native-abi)
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$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,vdsold_and_vdso_check)
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$(obj)/vdso.so: OBJCOPYFLAGS := -S
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$(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE
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$(call if_changed,objcopy)
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obj-y += vdso.o
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$(obj)/vdso.o : $(obj)/vdso.so
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