From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388014AbgF2TrP (ORCPT ); Mon, 29 Jun 2020 15:47:15 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 054E3C03E979 for ; Mon, 29 Jun 2020 12:47:16 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id d10so7496448pls.5 for ; Mon, 29 Jun 2020 12:47:16 -0700 (PDT) MIME-Version: 1.0 References: <20200629061840.4065483-1-keescook@chromium.org> <20200629061840.4065483-15-keescook@chromium.org> In-Reply-To: <20200629061840.4065483-15-keescook@chromium.org> From: Nick Desaulniers Date: Mon, 29 Jun 2020 12:47:03 -0700 Message-ID: Subject: Re: [PATCH v4 14/17] arm/build: Warn on orphan section placement Content-Type: text/plain; charset="UTF-8" Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kees Cook Cc: Will Deacon , Catalin Marinas , Mark Rutland , Ard Biesheuvel , Peter Collingbourne , James Morse , Borislav Petkov , Thomas Gleixner , Ingo Molnar , Russell King , Masahiro Yamada , Arvind Sankar , Nathan Chancellor , Arnd Bergmann , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , clang-built-linux , linux-arch , linux-efi , Linux ARM , LKML Message-ID: <20200629194703.MrCMMGSTrI5EhNyZEFOupng8r2rvjGsd0qHV_jKlixU@z> On Sun, Jun 28, 2020 at 11:18 PM Kees Cook wrote: > > We don't want to depend on the linker's orphan section placement > heuristics as these can vary between linkers, and may change between > versions. All sections need to be explicitly named in the linker > script. > > Specifically, this would have made a recently fixed bug very obvious: > > ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup' > > Discard unneeded sections .iplt, .rel.iplt, .igot.plt, and .modinfo. > > Add missing text stub sections .vfp11_veneer and .v4_bx. > > Add debug sections explicitly. > > Finally enable orphan section warning. > > Signed-off-by: Kees Cook Thanks for following up on the previous suggestion regarding .glu_7 / .glu_7t ordering. LGTM Reviewed-by: Nick Desaulniers > --- > arch/arm/include/asm/vmlinux.lds.h | 6 +++++- > arch/arm/kernel/vmlinux-xip.lds.S | 1 + > arch/arm/kernel/vmlinux.lds.S | 1 + > 3 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h > index c66b16cd8837..d44fae722e7a 100644 > --- a/arch/arm/include/asm/vmlinux.lds.h > +++ b/arch/arm/include/asm/vmlinux.lds.h > @@ -39,6 +39,8 @@ > __idmap_text_end = .; \ > > #define ARM_COMMON_DISCARD \ > + *(.iplt) *(.rel.iplt) *(.igot.plt) \ > + *(.modinfo) \ > *(.discard) \ > *(.discard.*) > > @@ -63,7 +65,9 @@ > #define ARM_STUBS_TEXT \ > *(.gnu.warning) \ > *(.glue_7) \ > - *(.glue_7t) > + *(.glue_7t) \ > + *(.vfp11_veneer) \ > + *(.v4_bx) > > #define ARM_TEXT \ > IDMAP_TEXT \ > diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S > index 57fcbf55f913..11ffa79751da 100644 > --- a/arch/arm/kernel/vmlinux-xip.lds.S > +++ b/arch/arm/kernel/vmlinux-xip.lds.S > @@ -150,6 +150,7 @@ SECTIONS > _end = .; > > STABS_DEBUG > + DWARF_DEBUG > ARM_DETAILS > } > > diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S > index 1d3d3b599635..dc672fe35de3 100644 > --- a/arch/arm/kernel/vmlinux.lds.S > +++ b/arch/arm/kernel/vmlinux.lds.S > @@ -149,6 +149,7 @@ SECTIONS > _end = .; > > STABS_DEBUG > + DWARF_DEBUG > ARM_DETAILS > } > > -- > 2.25.1 > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20200629061840.4065483-15-keescook%40chromium.org. -- Thanks, ~Nick Desaulniers