This is the mail archive of the
binutils@sourceware.org
mailing list for the binutils project.
Re: PATCH: Add functions to write core notes for i386/amd64
> Date: Mon, 19 Apr 2010 11:14:22 -0700
> From: "H.J. Lu" <hjl.tools@gmail.com>
>
> On Mon, Apr 19, 2010 at 10:56 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> Date: Mon, 19 Apr 2010 09:20:11 -0700
> >> From: "H.J. Lu" <hjl.tools@gmail.com>
> >>
> >> On Mon, Apr 19, 2010 at 9:03 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> >> > This adds the necessary backend functions to write proper core notes
> >> > like the ppc code already has. ?This is necessary for GDB to generate
> >> > proper 32-bit core dumps on 64-bit systems.
> >> > ok?
> >> >
> >> >
> >> > 2010-04-19 ?Mark Kettenis ?<kettenis@gnu.org>
> >> >
> >> > ? ? ? ?* elf64-x86-64.c (elf64_x86_64_write_core_note): New function.
> >> > ? ? ? ?(elf_backend_write_core_note): Define.
> >> > ? ? ? ?* elf32-i386.c (elf_i386_write_core_note): New function.
> >> > ? ? ? ?(elf_backend_write_core_note): Define.
> >> >
> >>
> >> It is not OK. I am not sure if it will work for Linux since Linux has
> >> different note sizes.
> >
> > Where do you think I tested this code?
> >
> >> In any case, after
> >>
> >> http://sourceware.org/ml/binutils/2010-04/msg00131.html
> >>
> >> NT_PRPSINFO and NT_PRSTATUS should work fine on
> >> Linux/x86-64.
> >
> > No, currently GDB writes out bogus notes for 32-bit core dumps on
> > Linux/amd64 systems.
>
> Changing elf64-x86-64.c alone won't fix it. Have you tried your
> GDB fix without changing elf64-x86-64.c?
The change in elf64-x86-64.c won't help the 32-bit case at all. It is
just there for consistency. And eventually *all* Linux ELF BFD
targets should implement the core note writing functions of course.
And yes, the elf32-i386.c change is not enough to fix things. But at
least it will make things a bit clearer, since it will stop GDB from
generating broken core dumps.
> >> I think the proper way to fix it is to define PRPSINFO32_T and
> >> PRPSINFO32_T for your x86-64 hosts.
> >
> > The long term plan in GDB is to make it possible to generate core
> > dumps even on non-native configurations. ?In order to do that, it is
> > necessary to add these functions that write out the proper core notes
> > without depending on any host-specific header files.
> >
>
> I thought about it. In theory, it is possible since GDB does have all
> register info. I think reading core is OK today. Writing core is a problem.
> I'd like to see the complete patch for non-native gcore. We may
> need to adjust BFD interface to support it.
No I don't have a diff; I was talking about long term plans. Further
BFD changes may be necessary. But at least my diff brings Linux
i386/amd64 with the other Linux target that implements biarch core
file support in BFD.