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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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cf12469600
The time-related VDSO functionality was introduced in 2021 in commit87f3248cdb("csky: Reconstruct VDSO framework") and commit0d3b051adb("csky: Add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO"). However the corresponding aux-vector entry AT_SYSINFO_EHDR was never wired up, making these functions impossible to test or use. The VDSO itself is kept as it also provides rt_sigreturn which is exposed differently to userspace. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-1-b64f0842d512@linutronix.de
55 lines
1.8 KiB
Makefile
55 lines
1.8 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0-only
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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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# Symbols present in the vdso
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vdso-syms += rt_sigreturn
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# Files to link into the vdso
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obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o
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ifneq ($(c-gettimeofday-y),)
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CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
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endif
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ccflags-y := -fno-stack-protector -DBUILD_VDSO32
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# Build rules
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targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds vdso-dummy.o
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obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
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obj-y += vdso.o vdso-syms.o
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CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
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# Force dependency
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$(obj)/vdso.o: $(obj)/vdso.so
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SYSCFLAGS_vdso.so.dbg = $(c_flags)
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$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
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$(call if_changed,vdsold)
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SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
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-Wl,--build-id=sha1 -Wl,--hash-style=both
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$(obj)/vdso-syms.S: $(obj)/vdso.so FORCE
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$(call if_changed,so2s)
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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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# 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 __vdso_xxx symbol offsets.
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quiet_cmd_vdsold = VDSOLD $@
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cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \
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-Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \
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$(CROSS_COMPILE)objcopy \
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$(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \
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rm $@.tmp
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# Extracts symbol offsets from the VDSO, converting them into an assembly file
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# that contains the same symbols at the same offsets.
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quiet_cmd_so2s = SO2S $@
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cmd_so2s = $(NM) -D $< | $(src)/so2s.sh > $@
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