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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 19514fc665 ("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>
78 lines
2.6 KiB
Makefile
78 lines
2.6 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0-only
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#
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# Makefile for compat_vdso
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#
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# Symbols present in the compat_vdso
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compat_vdso-syms = rt_sigreturn
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compat_vdso-syms += getcpu
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compat_vdso-syms += flush_icache
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COMPAT_CC := $(CC)
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COMPAT_LD := $(LD)
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# binutils 2.35 does not support the zifencei extension, but in the ISA
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# spec 20191213, G stands for IMAFD_ZICSR_ZIFENCEI.
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ifdef CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
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COMPAT_CC_FLAGS := -march=rv32g -mabi=ilp32
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else
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COMPAT_CC_FLAGS := -march=rv32imafd -mabi=ilp32
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endif
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COMPAT_LD_FLAGS := -melf32lriscv
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# Disable attributes, as they're useless and break the build.
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COMPAT_CC_FLAGS += $(call cc-option,-mno-riscv-attribute)
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COMPAT_CC_FLAGS += $(call as-option,-Wa$(comma)-mno-arch-attr)
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# Files to link into the compat_vdso
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obj-compat_vdso = $(patsubst %, %.o, $(compat_vdso-syms)) note.o
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# Build rules
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targets := $(obj-compat_vdso) compat_vdso.so compat_vdso.so.dbg compat_vdso.lds
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obj-compat_vdso := $(addprefix $(obj)/, $(obj-compat_vdso))
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obj-y += compat_vdso.o
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CPPFLAGS_compat_vdso.lds += -P -C -DCOMPAT_VDSO -U$(ARCH)
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# Disable profiling and instrumentation for VDSO code
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GCOV_PROFILE := n
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KCOV_INSTRUMENT := n
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KASAN_SANITIZE := n
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UBSAN_SANITIZE := n
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# Force dependency
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$(obj)/compat_vdso.o: $(obj)/compat_vdso.so
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# link rule for the .so file, .lds has to be first
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$(obj)/compat_vdso.so.dbg: $(obj)/compat_vdso.lds $(obj-compat_vdso) FORCE
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$(call if_changed,compat_vdsold)
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LDFLAGS_compat_vdso.so.dbg = -shared -S -soname=linux-compat_vdso.so.1 \
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--build-id=sha1 --hash-style=both --eh-frame-hdr
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$(obj-compat_vdso): %.o: %.S FORCE
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$(call if_changed_dep,compat_vdsoas)
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# strip rule for the .so file
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$(obj)/%.so: OBJCOPYFLAGS := -S
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$(obj)/%.so: $(obj)/%.so.dbg FORCE
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$(call if_changed,objcopy)
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# Generate VDSO offsets using helper script
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gen-compat_vdsosym := $(srctree)/$(src)/gen_compat_vdso_offsets.sh
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quiet_cmd_compat_vdsosym = VDSOSYM $@
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cmd_compat_vdsosym = $(NM) $< | $(gen-compat_vdsosym) | LC_ALL=C sort > $@
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include/generated/compat_vdso-offsets.h: $(obj)/compat_vdso.so.dbg FORCE
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$(call if_changed,compat_vdsosym)
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# actual build commands
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# The DSO images are built using a special linker script
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# Make sure only to export the intended __compat_vdso_xxx symbol offsets.
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quiet_cmd_compat_vdsold = VDSOLD $@
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cmd_compat_vdsold = $(COMPAT_LD) $(ld_flags) $(COMPAT_LD_FLAGS) -T $(filter-out FORCE,$^) -o $@.tmp && \
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$(OBJCOPY) $(patsubst %, -G __compat_vdso_%, $(compat_vdso-syms)) $@.tmp $@ && \
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rm $@.tmp
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# actual build commands
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quiet_cmd_compat_vdsoas = VDSOAS $@
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cmd_compat_vdsoas = $(COMPAT_CC) $(a_flags) $(COMPAT_CC_FLAGS) -c -o $@ $<
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