48f6430505
glibc added support for .gnu.hash in 2006 and .hash has been obsoleted
for more than one decade in many Linux distributions. Using
--hash-style=sysv might imply unaddressed issues and confuse readers.
Just drop the option and rely on the linker default, which is likely
"both", or "gnu" when the distribution really wants to eliminate sysv
hash overhead.
Similar to commit 6b7e26547f ("x86/vdso: Emit a GNU hash").
Signed-off-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20240718173423.1574395-1-maskray@google.com
Signed-off-by: Will Deacon <will@kernel.org>
73 lines
2.3 KiB
Makefile
73 lines
2.3 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# Building a vDSO image for AArch64.
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#
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# Author: Will Deacon <will.deacon@arm.com>
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# Heavily based on the vDSO Makefiles for other archs.
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#
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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 := vgettimeofday.o note.o sigreturn.o
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# Build rules
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targets := $(obj-vdso) vdso.so vdso.so.dbg
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obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
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btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
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# -Bsymbolic has been added for consistency with arm, the compat vDSO and
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# potential future proofing if we end up with internal calls to the exported
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# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
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# preparation in build-time C")).
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ldflags-y := -shared -soname=linux-vdso.so.1 \
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-Bsymbolic --build-id=sha1 -n $(btildflags-y)
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ifdef CONFIG_LD_ORPHAN_WARN
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ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
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endif
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ldflags-y += -T
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ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
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ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
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# -Wmissing-prototypes and -Wmissing-declarations are removed from
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# the CFLAGS of vgettimeofday.c to make possible to build the
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# kernel with CONFIG_WERROR enabled.
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CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
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$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
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$(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
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-Wmissing-prototypes -Wmissing-declarations
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CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
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ifneq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
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endif
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targets += vdso.lds
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CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
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# Link rule for the .so file, .lds has to be first
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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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# 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-vdsosym := $(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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# Actual build commands
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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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