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Re: PING^N: [PATCH] Add --enable-static-pie to build static PIE [BZ #19574]
- From: "Maciej W. Rozycki" <macro at mips dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 1 Dec 2017 01:57:51 +0000
- Subject: Re: PING^N: [PATCH] Add --enable-static-pie to build static PIE [BZ #19574]
- Authentication-results: sourceware.org; auth=none
- References: <CAMe9rOoyPf-77=cqmEW5Vg2KHwq48g6giW38qpA=oDUsnHaxCA@mail.gmail.com> <alpine.DEB.2.20.1711011603010.26405@digraph.polyomino.org.uk> <CAMe9rOrWi1W+F6K3TRL-2ipz-K4e0aP0ywsVg0XWgdCU1FV7OQ@mail.gmail.com> <CAMe9rOrTW7-JBtfOWjQrqMtS6Kp8efsAAbouFwQOnaAzh=sNpA@mail.gmail.com> <CAMe9rOr5qR-MnP+bEY_3OPdPK1qTnn_7JLi3Xn688E9JWKr1Zw@mail.gmail.com> <5A12C781.3030700@arm.com> <CAMe9rOohYeS4BJFp=TB4Zz26V4K2n8ZXSJX9kYqgEa=eW+w1xQ@mail.gmail.com> <5A18196C.90208@arm.com> <CAMe9rOqFfabivUDke1_ZxyEtV+L9T7VwKKdsdnR9M418L2TQBg@mail.gmail.com> <CAMe9rOpNdwd52vEnAUzOkmwkJXUWZz9-=dc9xfeZ96CYVM=8gQ@mail.gmail.com> <02278c7c-ade4-c8f2-c978-e66f77a101bd@redhat.com> <alpine.DEB.2.00.1711302227190.31156@tp.orcam.me.uk> <CAMe9rOpDRknZANuSvXAqU_qaXzGRjt=uY5BZLJoE_o9Ke+9yfw@mail.gmail.com> <alpine.DEB.2.00.1711302308170.31156@tp.orcam.me.uk> <CAMe9rOoaP=LT16Ee=-MOsL=zpem5XDjo4avhkJgC38FbeqSF4w@mail.gmail.com>
On Thu, 30 Nov 2017, H.J. Lu wrote:
> > However overall all these MIPS relocations are strictly non-PIC ones, so
> > clearly this code has not been correctly built.
>
> That is MIPS specific issue. It could be bfd_link_pic vs bfd_link_executable
> in MIPS linker backend.
Well, these relocations are produced by GAS, which obviously has nothing
to do with linking. You need to find a way for them not to be produced in
the first place, as they are not valid in a PIE executable link.
> > AFAICT you need to pass -DPIC to GCC when assembling sysdeps/mips/start.S
> > to get a position-independent intermediate object. The same applies to
> > our other MIPS assembly sources.
>
> Everything is compiled with -fPIE -DPIC:
>
> +ifeq (yes,$(enable-static-pie))
> +pic-default = -DPIC
> +pie-default = $(pie-ccflag)
> +ifeq (yes,$(have-static-pie))
> +default-pie-ldflag = -static-pie
> +else
> +default-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
> +endif
> +endif
Well, that doesn't prove that these options actually make it to the GCC
invocation line for say rcrt1.o. Quoting the actual line for rcrt1.o from
a build log would be more useful.
Maciej