Commit-ID: dda1e95cee38b416b23f751cac65421d781e3c10 Gitweb: http://git.kernel.org/tip/dda1e95cee38b416b23f751cac65421d781e3c10 Author: Andy Lutomirski <luto@xxxxxxxxxxxxxx> AuthorDate: Fri, 20 Jun 2014 12:20:44 -0700 Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> CommitDate: Fri, 20 Jun 2014 13:18:49 -0700 x86/vdso: Create .build-id links for unstripped vdso files With this change, doing 'make vdso_install' and telling gdb: set debug-file-directory /lib/modules/KVER/vdso will enable vdso debugging with symbols. This is useful for testing, but kernel RPM builds will probably want to manually delete these symlinks or otherwise do something sensible when they strip the vdso/*.so files. If ld does not support --build-id, then the symlinks will not be created. Note that kernel packagers that use vdso_install may need to adjust their packaging scripts to accomdate this change. For example, Fedora's scripts create build-id symlinks themselves in a different location, so the spec should probably be updated to remove the symlinks created by make vdso_install. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/a424b189ce3ced85fe1e82d032a20e765e0fe0d3.1403291930.git.luto@xxxxxxxxxxxxxx Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> --- arch/x86/vdso/Makefile | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile index 2c1ca98..68a15c4 100644 --- a/arch/x86/vdso/Makefile +++ b/arch/x86/vdso/Makefile @@ -169,14 +169,24 @@ quiet_cmd_vdso = VDSO $@ sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \ - -Wl,-Bsymbolic $(LTO_CFLAGS) + $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS) GCOV_PROFILE := n # -# Install the unstripped copies of vdso*.so. +# Install the unstripped copies of vdso*.so. If our toolchain supports +# build-id, install .build-id links as well. # quiet_cmd_vdso_install = INSTALL $(@:install_%=%) - cmd_vdso_install = cp $< $(MODLIB)/vdso/$(@:install_%=%) +define cmd_vdso_install + cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \ + if readelf -n $< |grep -q 'Build ID'; then \ + buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \ + first=`echo $$buildid | cut -b-2`; \ + last=`echo $$buildid | cut -b3-`; \ + mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \ + ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \ + fi +endef vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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