| Message ID | 1403765204-17617-1-git-send-email-achandran@mvista.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jun 26, 2014 at 07:46:44AM +0100, Arun Chandran wrote: > Selecting CPU_BIG_ENDIAN and building the kernel fails just after > building it for little endian. According to Documentation/kbuild/makefiles.txt, > it is a common mistake to forget 'FORCE' while using 'if_changed' This is a little confusing, because we jump from the high level problem to a very specific problem detail with nothing to link the two. How about: Building a kernel with CPU_BIG_ENDIAN fails if there are stale objects from a !CPU_BIG_ENDIAN build. Due to a missing FORCE prerequisite on an if_changed rule in the VDSO Makefile, we attempt to link a stale LE object into the new BE kernel. According to Documentation/kbuild/makefiles.txt FORCE is required for if_changed rules, and forgetting it is a common mistake. > So fix it by 'Forcing' the build of vdso. Fixes build errors like these: > > arch/arm64/kernel/vdso/note.o: compiled for a little endian system and target is big endian > failed to merge target specific data of file arch/arm64/kernel/vdso/note.o > > arch/arm64/kernel/vdso/sigreturn.o: compiled for a little endian system and target is big endian > failed to merge target specific data of file arch/arm64/kernel/vdso/sigreturn.o > > Signed-off-by: Arun Chandran <achandran@mvista.com> Any reason for bot picking up my Tested-by [1]? The patch seems to be the same. Mark. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/266571.html > --- > arch/arm64/kernel/vdso/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > index 6d20b7d..a268a9a 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -43,7 +43,7 @@ $(obj)/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE > $(call if_changed,vdsosym) > > # Assembly rules for the .S files > -$(obj-vdso): %.o: %.S > +$(obj-vdso): %.o: %.S FORCE > $(call if_changed_dep,vdsoas) > > # Actual build commands > -- > 1.7.9.5 > >
Hi, On Thu, Jun 26, 2014 at 2:59 PM, Mark Rutland <mark.rutland@arm.com> wrote: > On Thu, Jun 26, 2014 at 07:46:44AM +0100, Arun Chandran wrote: >> Selecting CPU_BIG_ENDIAN and building the kernel fails just after >> building it for little endian. According to Documentation/kbuild/makefiles.txt, >> it is a common mistake to forget 'FORCE' while using 'if_changed' > > This is a little confusing, because we jump from the high level problem > to a very specific problem detail with nothing to link the two. > > How about: > > Building a kernel with CPU_BIG_ENDIAN fails if there are stale objects > from a !CPU_BIG_ENDIAN build. Due to a missing FORCE prerequisite on an > if_changed rule in the VDSO Makefile, we attempt to link a stale LE > object into the new BE kernel. According to > Documentation/kbuild/makefiles.txt FORCE is required for if_changed > rules, and forgetting it is a common mistake. > Yes that is a better one. I will make the change. >> So fix it by 'Forcing' the build of vdso. Fixes build errors like these: >> >> arch/arm64/kernel/vdso/note.o: compiled for a little endian system and target is big endian >> failed to merge target specific data of file arch/arm64/kernel/vdso/note.o >> >> arch/arm64/kernel/vdso/sigreturn.o: compiled for a little endian system and target is big endian >> failed to merge target specific data of file arch/arm64/kernel/vdso/sigreturn.o >> >> Signed-off-by: Arun Chandran <achandran@mvista.com> > > Any reason for bot picking up my Tested-by [1]? The patch seems to be > the same. Sorry I missed that. Will include in my next patch --Arun > > Mark. > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-June/266571.html > >> --- >> arch/arm64/kernel/vdso/Makefile | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile >> index 6d20b7d..a268a9a 100644 >> --- a/arch/arm64/kernel/vdso/Makefile >> +++ b/arch/arm64/kernel/vdso/Makefile >> @@ -43,7 +43,7 @@ $(obj)/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE >> $(call if_changed,vdsosym) >> >> # Assembly rules for the .S files >> -$(obj-vdso): %.o: %.S >> +$(obj-vdso): %.o: %.S FORCE >> $(call if_changed_dep,vdsoas) >> >> # Actual build commands >> -- >> 1.7.9.5 >> >>
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 6d20b7d..a268a9a 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -43,7 +43,7 @@ $(obj)/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE $(call if_changed,vdsosym) # Assembly rules for the .S files -$(obj-vdso): %.o: %.S +$(obj-vdso): %.o: %.S FORCE $(call if_changed_dep,vdsoas) # Actual build commands
Selecting CPU_BIG_ENDIAN and building the kernel fails just after building it for little endian. According to Documentation/kbuild/makefiles.txt, it is a common mistake to forget 'FORCE' while using 'if_changed' So fix it by 'Forcing' the build of vdso. Fixes build errors like these: arch/arm64/kernel/vdso/note.o: compiled for a little endian system and target is big endian failed to merge target specific data of file arch/arm64/kernel/vdso/note.o arch/arm64/kernel/vdso/sigreturn.o: compiled for a little endian system and target is big endian failed to merge target specific data of file arch/arm64/kernel/vdso/sigreturn.o Signed-off-by: Arun Chandran <achandran@mvista.com> --- arch/arm64/kernel/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)