[Bug corefiles/14383] New: Corefile support for arm-elf-none targets

[Bug corefiles/14383] New: Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14383

             Bug #: 14383
           Summary: Corefile support for arm-elf-none targets
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: corefiles
        AssignedTo: unassigned@sourceware.org
        ReportedBy: fredrik.hederstierna@securitas-direct.com
    Classification: Unclassified


Today corefiles are only supported by Linux targets for ARM.

It would be great to have the possibility to have basic corefiles also for
non-Linux ARM targets.

The ideal would be to be able to eg. run remote serial GDB to target dev-board
and eg. put breakpoints in exception handler, then run 'generate-core-file' to
be able to debug it later off-line using core-files from disk.

Possibly the existing code for corefiles in in 'arm-linux-tdep.c'.
Could this be moved to the more generic 'arm-tdep.c' to enable a
default-corefile support that could be overridden when calling osabi_init() ?

I submit a patch that seems to work, but more as an example how it could be
done perhaps, any other suggestions for solutions are ofcourse welcome.

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #1 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> 2012-07-22 07:02:19 UTC ---
Created attachment 6544
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6544
Idea how it could be done maybe

Maybe this is crazy, but I tested it and the patched gdb did accept my
corefile.
I'm not sure about how gcore running generate-core-file will work as in a
none-target there are not known threads nor processes, so I guess it will just
be one single dummy process running.

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #2 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> 2012-11-05 09:55:04 UTC ---
Created attachment 6717
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6717
Added new default core file support files to build.

Default core file support in separate file.

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #3 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> 2012-11-05 09:56:13 UTC ---
Created attachment 6718
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6718
arm-none-tdep.h

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14383

Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Attachment #6544|0                           |1
        is obsolete|                            |

--- Comment #4 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> 2012-11-05 09:57:07 UTC ---
Created attachment 6719
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6719
arm-none-tdep.c

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #5 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> 2012-11-05 10:03:45 UTC ---
I added a solution where Linux core file support was duplicated, separated, and
modified to make an independent arm none/bare metal core file feature in GDB.

It also works with remote targets, using 'gcore' or 'generate-core-file'
command to generate code while debugging.

Though in this case all RAM must be setup in sections for linker script.
I had to add 'dummy sections' for slack RAM like stacks and other non-linktime
defined RAM, example from linker script (0x1000 is max RAM size):

  .slack_ram (NOLOAD) :
  {
    . += (0x1000 - SIZEOF(.data) - SIZEOF(.bss));
  } > RAM

I will also add simple core file generator code to be able to eg. write all RAM
to flash bank while crashing/asserting, to be able at a later stage send
core-file-template to PC and at a later stage use a tool to generate a 'real'
core. This tool might be put on a separate server.
/Fredrik

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[will.newton at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

Will Newton <will.newton at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |will.newton at gmail dot com
           Severity|normal                      |enhancement

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[Mail at Robitzki dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

Torsten Robitzki <Mail at Robitzki dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |Mail at Robitzki dot com

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[Mail at Robitzki dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #6 from Torsten Robitzki <Mail at Robitzki dot com> ---
Hi,
this sounds like a wonderful idea! Is there anything I can do to help to get
this into GDB? I'm currently developing on ARM Cortex M0 targets. I could test
the patch.

If someone gives me some pointers, I could write a tool to convert the ram
dumps to a real core file.

Let me know if there is anything I could do to help.

kind regards,

Torsten

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #7 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> ---
Created attachment 12903
  --> https://sourceware.org/bugzilla/attachment.cgi?id=12903&action=edit
Patch for GDB-7.11.1

Patch to add corefile support for arm-none-eabi

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #8 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> ---
Added a patch version I made for GDB-7.11.1

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #9 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> ---
Created attachment 12912
  --> https://sourceware.org/bugzilla/attachment.cgi?id=12912&action=edit
Adds corefile support for arm-none-eabi

Rebased and updated to GDB 10 master,
this patch adds corefile support for arm-none-eabi.

Tried to remote target debug my Cortex-M4 board, and successfully did
(gdb) gcore testing.core
Saved corefile testing.core

then later off-line, did debug corefile without target connection locally:
$ arm-none-eabi-gdb testing.elf testing.core

It worked fine, I could check 'bt' for call-backtrace etc.

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

--- Comment #10 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Andrew Burgess <aburgess@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=9b715c68e84d93d6671fac661cad391970462ffb

commit 9b715c68e84d93d6671fac661cad391970462ffb
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date:   Wed Jan 20 15:13:16 2021 +0000

    gdb/arm: add support for bare-metal core dumps

    This commit adds support for bare metal core dumps on the ARM target,
    and is based off of this patch submitted to the mailing list:

      https://sourceware.org/pipermail/gdb-patches/2020-October/172845.html

    Compared to the version linked above this version is updated to take
    account of recent changes to the core dump infrastructure in GDB,
    there is now more shared infrastructure for core dumping within GDB,
    and also some common bare metal core dumping infrastructure.  As a
    result this patch is smaller than the original proposed patch.

    Further, the original patch included some unrelated changes to the
    simulator that have been removed from this version.

    I have written a ChangeLog entry as the original patch was missing
    one.

    I have done absolutely no testing of this patch.  It is based on the
    original submitted patch, which I assume was tested, but after my
    modifications things might have been broken, however, the original
    patch author has tested this version and reported it as being good:

      https://sourceware.org/pipermail/gdb-patches/2021-May/178900.html

    The core dump format is based around generating an ELF containing
    sections for the writable regions of memory that a user could be
    using.  Which regions are dumped rely on GDB's existing common core
    dumping code, GDB will attempt to figure out the stack and heap as
    well as copying out writable data sections as identified by the
    original ELF.

    Register information is added to the core dump using notes, just as it
    is for Linux of FreeBSD core dumps.  The note types used consist of
    the 2 basic types you would expect in a OS based core dump,
    NT_PRPSINFO, NT_PRSTATUS, along with the architecture specific
    NT_ARM_VFP note.

    The data layouts for each note type are described below, in all cases,
    all padding fields should be set to zero.

    Note NT_PRPSINFO is optional.  Its data layout is:

      struct prpsinfo_t
      {
        uint8_t padding[28];
        char fname[16];
        char psargs[80];
      }

    Field 'fname' - null terminated string consisting of the basename of
        (up to the fist 15 characters of) the executable.  Any additional
        space should be set to zero.  If there's no executable name then
        this field can be set to all zero.

    Field 'psargs' - a null terminated string up to 80 characters in
        length.  Any additional space should be filled with zero.  This
        field contains the full executable path and any arguments passed
        to the executable.  If there's nothing sensible to write in this
        field then fill it with zero.

    Note NT_PRSTATUS is required, its data layout is:

      struct prstatus_t
      {
        uint8_t padding_1[12];
        uint16_t sig;
        uint8_t padding_2[10];
        uint32_t thread_id;
        uint8_t padding_3[44];
        uint32_t gregs[18];
      }

    Field 'sig' - the signal that stopped this thread.  It's implementation
        defined what this field actually means.  Within GDB this will be
        the signal number that the remote target reports as the stop
        reason for this thread.

    Field 'thread_is' - the thread id for this thread.  It's implementation
        defined what this field actually means.  Within GDB this will be
        thread thread-id that is assigned to each remote thread.

    Field 'gregs' - holds the general purpose registers $a1 through to $pc
        at indices 0 to 15.  At index 16 the program status register.
        Index 17 should be set to zero.

    Note NT_ARM_VFP is optional, its data layout is:

      armvfp_t
      {
        uint64_t regs[32];
        uint32_t fpscr;
      }

    Field 'regs' - holds the 32 d-registers 0 to 31 in order.

    Field 'fpscr' - holds the fpscr register.

    The rules for ordering the notes is the same as for Linux.  The
    NT_PRSTATUS note must come before any other notes about additional
    register sets.  And for multi-threaded targets all registers for a
    single thread should be grouped together.  This is because only
    NT_PRSTATUS includes a thread-id, all additional register notes after
    a NT_PRSTATUS are assumed to belong to the same thread until a
    different NT_PRSTATUS is seen.

    gdb/ChangeLog:

            PR gdb/14383
            * Makefile.in (ALL_TARGET_OBS): Add arm-none-tdep.o.
            (ALLDEPFILES): Add arm-none-tdep.c
            * arm-none-tdep.c: New file.
            * configure.tgt (arm*-*-*): Add arm-none-tdep.o to cpu_obs.

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[Bug corefiles/14383] Corefile support for arm-elf-none targets

[fredrik.hederstierna@securitas-direct.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14383

Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #11 from Fredrik Hederstierna <fredrik.hederstierna@securitas-direct.com> ---
ARM bare-metal corefile supported added in GDB-11 release.

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