From 90f777beb788d08300f4a1482cb4fd37a401b472 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Fri, 8 Jul 2016 12:13:20 +0100 Subject: [PATCH] arm64: Fix vdso-offsets.h dependency arch/arm64/kernel/{vdso,signal}.c include generated/vdso-offsets.h, and therefore the symbol offsets must be generated before these files are compiled. The current rules in arm64/kernel/Makefile do not actually enforce this, because even though $(obj)/vdso is listed as a prerequisite for vdso-offsets.h, this does not result in the intended effect of building the vdso subdirectory (before all the other objects). As a consequence, depending on the order in which the rules are followed, vdso-offsets.h is updated or not before arm64/kernel/{vdso,signal}.o are built. The current rules also impose an unnecessary dependency on vdso-offsets.h for all arm64/kernel/*.o, resulting in unnecessary rebuilds. This patch removes the arch/arm64/kernel/vdso/vdso-offsets.h file generation, leaving only the include/generated/vdso-offsets.h one. It adds a forced dependency check of the vdso-offsets.h file in arch/arm64/kernel/Makefile which, if not up to date according to the arch/arm64/kernel/vdso/Makefile rules (depending on vdso.so.dbg), will trigger the vdso/ subdirectory build and vdso-offsets.h re-generation. Automatic kbuild dependency rules between kernel/{vdso,signal}.c rules and vdso-offsets.h will guarantee that the vDSO object is built first, followed by the generated symbol offsets header file. Reported-by: Kevin Brodsky Signed-off-by: Catalin Marinas --- arch/arm64/kernel/Makefile | 7 ++++--- arch/arm64/kernel/vdso/Makefile | 7 +++---- 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 7700c0c23962..efffc231a244 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -54,6 +54,7 @@ obj-m += $(arm64-obj-m) head-y := head.o extra-y += $(head-y) vmlinux.lds -# vDSO - this must be built first to generate the symbol offsets -$(call objectify,$(arm64-obj-y)): $(obj)/vdso/vdso-offsets.h -$(obj)/vdso/vdso-offsets.h: $(obj)/vdso +# Check that the vDSO symbol offsets header file is up to date and re-generate +# it if necessary. +$(objtree)/include/generated/vdso-offsets.h: FORCE + $(Q)$(MAKE) $(build)=$(obj)/vdso $@ diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index b467fd0a384b..285433720202 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -23,7 +23,7 @@ GCOV_PROFILE := n ccflags-y += -Wl,-shared obj-y += vdso.o -extra-y += vdso.lds vdso-offsets.h +extra-y += vdso.lds CPPFLAGS_vdso.lds += -P -C -U$(ARCH) # Force dependency (incbin is bad) @@ -42,11 +42,10 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh quiet_cmd_vdsosym = VDSOSYM $@ define cmd_vdsosym - $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ && \ - cp $@ include/generated/ + $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ endef -$(obj)/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE +$(objtree)/include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE $(call if_changed,vdsosym) # Assembly rules for the .S files -- 2.20.1