[PATCH] arc: Add support for ARC HS extra registers in core files

Anton Kolesov Anton.Kolesov@synopsys.com
Tue Mar 31 09:41:28 GMT 2020


Hi Claudiu,

NT_ARC_V2 is the name that comes from Linux headers, so using different name can
cause confusion. "reg-v2" can be changed to something more specific I think,
however more specific than "reg-ext" because each type of section would have
different name and registers.

Anton

> -----Original Message-----
> From: Claudiu Zissulescu Ianculescu <claziss@gmail.com>
> Sent: Tuesday, March 31, 2020 12:30
> To: Shahab Vahedi <shahab.vahedi@gmail.com>
> Cc: Binutils <binutils@sourceware.org>; Anton Kolesov
> <akolesov@synopsys.com>; Shahab Vahedi <shahab@synopsys.com>; Claudiu
> Zissulescu <claziss@synopsys.com>; Francois Bedard
> <fbedard@synopsys.com>
> Subject: Re: [PATCH] arc: Add support for ARC HS extra registers in core files
> 
> Hi Shahab,
> 
> I don't really like the ARC_V2 name. All ARC variants can have extra registers
> from r32 to r59 called extension core registers :) I would go for something more
> generic like ARC_EXT_REG, or something like that
> 
> On Thu, Mar 26, 2020 at 5:02 PM Shahab Vahedi via Binutils
> <binutils@sourceware.org> wrote:
> >
> > From: Anton Kolesov <Anton.Kolesov@synopsys.com>
> >
> > When a coredump is generated, there are a few registers in ARC HS that
> > are put under a special section, namely ".reg-v2".
> > It is for backward compatibility reasons with older tools that we have
> > decided not to extend the generic ".reg" section.
> >
> > This patch makes it possible to display the information better
> > regarding that section.  Compare the output of "readelf" without and
> > with these changes:
> >
> > $ readelf -n core     # without the patch
> >   ...
> >   LINUX    0x0000000c  Unknown note type: (0x00000600)
> >    description data: 78 08 00 00 2f 6c 64 2d 75 43 6c 69
> >
> > $ readelf -n core     # with the patch
> >   ...
> >   LINUX    0x0000000c  NT_ARC_V2 (ARC HS accumulator/extra registers)
> >    description data: 78 08 00 00 2f 6c 64 2d 75 43 6c 69
> >
> > In another commit (soon to be submitted), GDB will makes use of these
> > changes to parse the extra section and its registers.
> >
> > bfd/ChangeLog
> > 2020-03-26  Anton Kolesov  <anton.kolesov@synopsys.com>
> >
> >         * elf-bfd.h (elfcore_write_arc_v2): Add prototype.
> >         * elf.c (elfcore_grok_arc_v2): New function.
> >         (elfcore_grok_note): Call the new function to handle the corresponding
> >         note.
> >         (elfcore_write_arc_v2): New function.
> >         (elfcore_write_register_note): Call the new function to handle the
> >         corresponding pseudo-sections.
> >
> > binutils/ChangeLog
> > 2020-03-26  Anton Kolesov  <anton.kolesov@synopsys.com>
> >
> >         * readelf.c (get_note_type): Handle NT_ARC_V2.
> >
> > include/elf/ChangeLog
> > 2020-03-26  Anton Kolesov  <anton.kolesov@synopsys.com>
> >
> >         * common.h (NT_ARC_V2): New macro definitions.
> > ---
> >  bfd/elf-bfd.h        |  2 ++
> >  bfd/elf.c            | 27 +++++++++++++++++++++++++++
> >  binutils/readelf.c   |  2 ++
> >  include/elf/common.h |  2 ++
> >  4 files changed, 33 insertions(+)
> >
> > diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h index
> > d4ac5152dfe..088bb77dd72 100644
> > --- a/bfd/elf-bfd.h
> > +++ b/bfd/elf-bfd.h
> > @@ -2730,6 +2730,8 @@ extern char *elfcore_write_aarch_sve
> >    (bfd *, char *, int *, const void *, int);  extern char
> > *elfcore_write_aarch_pauth
> >    (bfd *, char *, int *, const void *, int);
> > +extern char *elfcore_write_arc_v2
> > +  (bfd *, char *, int *, const void *, int);
> >  extern char *elfcore_write_lwpstatus
> >    (bfd *, char *, int *, long, int, const void *);  extern char
> > *elfcore_write_register_note diff --git a/bfd/elf.c b/bfd/elf.c index
> > 8ab7b3e2e81..63da5ce08b8 100644
> > --- a/bfd/elf.c
> > +++ b/bfd/elf.c
> > @@ -9820,6 +9820,12 @@ elfcore_grok_aarch_pauth (bfd *abfd,
> Elf_Internal_Note *note)
> >    return elfcore_make_note_pseudosection (abfd, ".reg-aarch-pauth",
> > note);  }
> >
> > +static bfd_boolean
> > +elfcore_grok_arc_v2 (bfd *abfd, Elf_Internal_Note *note) {
> > +  return elfcore_make_note_pseudosection (abfd, ".reg-arc-v2", note);
> > +}
> > +
> >  #if defined (HAVE_PRPSINFO_T)
> >  typedef prpsinfo_t   elfcore_psinfo_t;
> >  #if defined (HAVE_PRPSINFO32_T)                /* Sparc64 cross Sparc32 */
> > @@ -10379,6 +10385,13 @@ elfcore_grok_note (bfd *abfd,
> Elf_Internal_Note *note)
> >        else
> >         return TRUE;
> >
> > +    case NT_ARC_V2:
> > +      if (note->namesz == 6
> > +         && strcmp (note->namedata, "LINUX") == 0)
> > +       return elfcore_grok_arc_v2 (abfd, note);
> > +      else
> > +       return TRUE;
> > +
> >      case NT_ARM_VFP:
> >        if (note->namesz == 6
> >           && strcmp (note->namedata, "LINUX") == 0) @@ -11790,6
> > +11803,18 @@ elfcore_write_aarch_pauth (bfd *abfd,
> >                              note_name, NT_ARM_PAC_MASK, aarch_pauth,
> > size);  }
> >
> > +char *
> > +elfcore_write_arc_v2 (bfd *abfd,
> > +                     char *buf,
> > +                     int *bufsiz,
> > +                     const void *arc_v2,
> > +                     int size)
> > +{
> > +  char *note_name = "LINUX";
> > +  return elfcore_write_note (abfd, buf, bufsiz,
> > +                            note_name, NT_ARC_V2, arc_v2, size); }
> > +
> >  char *
> >  elfcore_write_register_note (bfd *abfd,
> >                              char *buf, @@ -11872,6 +11897,8 @@
> > elfcore_write_register_note (bfd *abfd,
> >      return elfcore_write_aarch_sve (abfd, buf, bufsiz, data, size);
> >    if (strcmp (section, ".reg-aarch-pauth") == 0)
> >      return elfcore_write_aarch_pauth (abfd, buf, bufsiz, data, size);
> > +  if (strcmp (section, ".reg-arc-v2") == 0)
> > +    return elfcore_write_arc_v2 (abfd, buf, bufsiz, data, size);
> >    return NULL;
> >  }
> >
> > diff --git a/binutils/readelf.c b/binutils/readelf.c index
> > a11297845e8..15b4f1cc661 100644
> > --- a/binutils/readelf.c
> > +++ b/binutils/readelf.c
> > @@ -17553,6 +17553,8 @@ get_note_type (Filedata * filedata, unsigned
> e_type)
> >         return _("NT_ARM_HW_BREAK (AArch hardware breakpoint registers)");
> >        case NT_ARM_HW_WATCH:
> >         return _("NT_ARM_HW_WATCH (AArch hardware watchpoint
> > registers)");
> > +      case NT_ARC_V2:
> > +       return _("NT_ARC_V2 (ARC HS accumulator/extra registers)");
> >        case NT_PSTATUS:
> >         return _("NT_PSTATUS (pstatus structure)");
> >        case NT_FPREGS:
> > diff --git a/include/elf/common.h b/include/elf/common.h index
> > 1c84ccb430e..e8447678226 100644
> > --- a/include/elf/common.h
> > +++ b/include/elf/common.h
> > @@ -652,6 +652,8 @@
> >                                         /*   note name must be "LINUX".  */
> >  #define NT_ARM_PAC_MASK        0x406           /* AArch pointer
> authentication code masks */
> >                                         /*   note name must be "LINUX".  */
> > +#define NT_ARC_V2      0x600           /* ARC HS accumulator/extra registers.
> */
> > +                                       /*   note name must be "LINUX".  */
> >  #define NT_SIGINFO     0x53494749      /* Fields of siginfo_t.  */
> >  #define NT_FILE                0x46494c45      /* Description of mapped files.  */
> >
> > --
> > 2.26.0
> >


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