[lld] r293519 - ELF: Align RELRO to the target page size rather than the max page size.

[Peter Collingbourne via llvm-commits]

Thanks. Committed r293674 which includes this change and a followup build
fix.

Peter

On Tue, Jan 31, 2017 at 10:46 AM, Hans Wennborg <hans at chromium.org> wrote:

> Sgtm.
>
> Peter, go ahead and commit it to the branch (or let me know, and I'll do
> it).
>
> On Mon, Jan 30, 2017 at 4:38 PM, Rui Ueyama via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Yes please.
> >
> > On Jan 30, 2017 10:32 AM, "Peter Collingbourne" <peter at pcc.me.uk> wrote:
> >>
> >> ruiu: OK to backport this to the 4.0 branch?
> >>
> >> Peter
> >>
> >> On Mon, Jan 30, 2017 at 10:20 AM, Peter Collingbourne via llvm-commits
> >> <llvm-commits at lists.llvm.org> wrote:
> >>>
> >>> Author: pcc
> >>> Date: Mon Jan 30 12:20:07 2017
> >>> New Revision: 293519
> >>>
> >>> URL: http://llvm.org/viewvc/llvm-project?rev=293519&view=rev
> >>> Log:
> >>> ELF: Align RELRO to the target page size rather than the max page size.
> >>>
> >>> If no bss sections appear after the relro segment, the loader will
> round
> >>> the r/w segment size to the target's page size. Align the relro size in
> >>> the
> >>> same way to ensure that it does not extend past the end of the
> program's
> >>> own memory region.
> >>>
> >>> Differential Revision: https://reviews.llvm.org/D29242
> >>>
> >>> Added:
> >>>     lld/trunk/test/ELF/aarch64-relro.s
> >>> Modified:
> >>>     lld/trunk/ELF/Writer.cpp
> >>>
> >>> Modified: lld/trunk/ELF/Writer.cpp
> >>> URL:
> >>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.
> cpp?rev=293519&r1=293518&r2=293519&view=diff
> >>>
> >>> ============================================================
> ==================
> >>> --- lld/trunk/ELF/Writer.cpp (original)
> >>> +++ lld/trunk/ELF/Writer.cpp Mon Jan 30 12:20:07 2017
> >>> @@ -1498,7 +1498,7 @@ template <class ELFT> void Writer<ELFT>:
> >>>        // The glibc dynamic loader rounds the size down, so we need to
> >>> round up
> >>>        // to protect the last page. This is a no-op on FreeBSD which
> >>> always
> >>>        // rounds up.
> >>> -      P.p_memsz = alignTo(P.p_memsz, Config->MaxPageSize);
> >>> +      P.p_memsz = alignTo(P.p_memsz, Target->PageSize);
> >>>      }
> >>>
> >>>      // The TLS pointer goes after PT_TLS. At least glibc will align
> it,
> >>>
> >>> Added: lld/trunk/test/ELF/aarch64-relro.s
> >>> URL:
> >>> http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/
> aarch64-relro.s?rev=293519&view=auto
> >>>
> >>> ============================================================
> ==================
> >>> --- lld/trunk/test/ELF/aarch64-relro.s (added)
> >>> +++ lld/trunk/test/ELF/aarch64-relro.s Mon Jan 30 12:20:07 2017
> >>> @@ -0,0 +1,13 @@
> >>> +# RUN: llvm-mc -filetype=obj -triple=aarch64-unknown-freebsd %s -o %t
> >>> +# RUN: ld.lld %t -o %t2
> >>> +# RUN: llvm-readobj -program-headers %t2 | FileCheck %s
> >>> +
> >>> +# CHECK:      Type: PT_GNU_RELRO
> >>> +# CHECK-NEXT: Offset:
> >>> +# CHECK-NEXT: VirtualAddress:
> >>> +# CHECK-NEXT: PhysicalAddress:
> >>> +# CHECK-NEXT: FileSize:
> >>> +# CHECK-NEXT: MemSize: 4096
> >>> +
> >>> +.section .data.rel.ro,"aw",%progbits
> >>> +.byte 1
> >>>
> >>>
> >>> _______________________________________________
> >>> llvm-commits mailing list
> >>> llvm-commits at lists.llvm.org
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> >>
> >>
> >>
> >>
> >> --
> >> --
> >> Peter
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> >
>



-- 
-- 
Peter
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