core file not loaded

core file not loaded

[Fabian Cenedese]

Hi

gdb-6.1.1 on cygwin, target=PPC

I tried to read a core dump file of our embedded target, but gdb gives
me an error:

(gdb) core N:/Temp/SAMCLASS/MemDmp00.bin
GDB can't read core files on this machine.
(gdb) core
GDB can't read core files on this machine.

I looked for the error message in the sources and found this:

/* Find a single core_stratum target in the list of targets and return it.
   If for some reason there is more than one, return NULL.  */

But I couldn't see what's wrong. What is needed to work with a core file?

Thanks

bye  Fabi

Re: core file not loaded

[Daniel Jacobowitz]

On Wed, Oct 06, 2004 at 01:32:03PM +0200, Fabian Cenedese wrote:
> Hi
> 
> gdb-6.1.1 on cygwin, target=PPC

More specific - what target triplet?

> 
> I tried to read a core dump file of our embedded target, but gdb gives
> me an error:
> 
> (gdb) core N:/Temp/SAMCLASS/MemDmp00.bin
> GDB can't read core files on this machine.
> (gdb) core
> GDB can't read core files on this machine.
> 
> I looked for the error message in the sources and found this:
> 
> /* Find a single core_stratum target in the list of targets and return it.
>    If for some reason there is more than one, return NULL.  */
> 
> But I couldn't see what's wrong. What is needed to work with a core file?

The target needs to tell GDB how to load core files.  This is a highly
OS-specific operation.

-- 
Daniel Jacobowitz

Re: core file not loaded

[Fabian Cenedese]

>> gdb-6.1.1 on cygwin, target=PPC
>
>More specific - what target triplet?

Sorry, --host=i686-pc-cygwin --target=powerpc-eabi

>> I tried to read a core dump file of our embedded target, but gdb gives
>> me an error:
>> 
>> (gdb) core N:/Temp/SAMCLASS/MemDmp00.bin
>> GDB can't read core files on this machine.
>> (gdb) core
>> GDB can't read core files on this machine.
>> 
>> I looked for the error message in the sources and found this:
>> 
>> /* Find a single core_stratum target in the list of targets and return it.
>>    If for some reason there is more than one, return NULL.  */
>> 
>> But I couldn't see what's wrong. What is needed to work with a core file?
>
>The target needs to tell GDB how to load core files.  This is a highly
>OS-specific operation.

My understanding was, that I could take a memory snapshot of the
target (in this case about 4MB) and feed this to gdb so gdb will use
this file for read accesses instead of reading a physical target (in
addition to the symbolfile). Is this wrong? Or is this not a core file?

Thanks

bye  Fabi

Re: core file not loaded

[Daniel Jacobowitz]

On Wed, Oct 06, 2004 at 04:16:08PM +0200, Fabian Cenedese wrote:
> 
> >> gdb-6.1.1 on cygwin, target=PPC
> >
> >More specific - what target triplet?
> 
> Sorry, --host=i686-pc-cygwin --target=powerpc-eabi
> 
> >> I tried to read a core dump file of our embedded target, but gdb gives
> >> me an error:
> >> 
> >> (gdb) core N:/Temp/SAMCLASS/MemDmp00.bin
> >> GDB can't read core files on this machine.
> >> (gdb) core
> >> GDB can't read core files on this machine.
> >> 
> >> I looked for the error message in the sources and found this:
> >> 
> >> /* Find a single core_stratum target in the list of targets and return it.
> >>    If for some reason there is more than one, return NULL.  */
> >> 
> >> But I couldn't see what's wrong. What is needed to work with a core file?
> >
> >The target needs to tell GDB how to load core files.  This is a highly
> >OS-specific operation.
> 
> My understanding was, that I could take a memory snapshot of the
> target (in this case about 4MB) and feed this to gdb so gdb will use
> this file for read accesses instead of reading a physical target (in
> addition to the symbolfile). Is this wrong? Or is this not a core file?

That's not a core file.  You can probably convert it to a core file,
but you'd also have to teach the BFD and GDB powerpc-eabi support to
recognize it as a powerpc-eabi core file.

A core file is one of several "standard" formats, generated by various
operating systems - lately, a particular kind of ELF object.  Easiest
might be to convert your binary dump to an ELF core file and copy
support from powerpc-linux.

Note that a memory dump isn't enough; for instance, you've lost all
register values.

-- 
Daniel Jacobowitz

Re: core file not loaded

[Paul Koning]

>>>>> "Daniel" == Daniel Jacobowitz <drow@false.org> writes:

 Daniel> On Wed, Oct 06, 2004 at 04:16:08PM +0200, Fabian Cenedese
 Daniel> wrote:
 >> >> gdb-6.1.1 on cygwin, target=PPC
 >> >
 >> >More specific - what target triplet?
 >> 
 >> Sorry, --host=i686-pc-cygwin --target=powerpc-eabi
 >> ...
 >> My understanding was, that I could take a memory snapshot of the
 >> target (in this case about 4MB) and feed this to gdb so gdb will
 >> use this file for read accesses instead of reading a physical
 >> target (in addition to the symbolfile). Is this wrong? Or is this
 >> not a core file?

 Daniel> That's not a core file.  You can probably convert it to a
 Daniel> core file, but you'd also have to teach the BFD and GDB
 Daniel> powerpc-eabi support to recognize it as a powerpc-eabi core
 Daniel> file.

 Daniel> A core file is one of several "standard" formats, generated
 Daniel> by various operating systems - lately, a particular kind of
 Daniel> ELF object.  Easiest might be to convert your binary dump to
 Daniel> an ELF core file and copy support from powerpc-linux.

 Daniel> Note that a memory dump isn't enough; for instance, you've
 Daniel> lost all register values.

The other issue (at least when last I looked) is that gdb is only
willing to handle corefiles for native builds, not for crossbuilds.

If your target state is more than just a single executing program,
you're really dealing with a kernel corefile, which is a whole
different class of beast.  

	  paul

Re: core file not loaded

[Kris Warkentin]

Paul Koning wrote:

>The other issue (at least when last I looked) is that gdb is only
>willing to handle corefiles for native builds, not for crossbuilds.
>
>If your target state is more than just a single executing program,
>you're really dealing with a kernel corefile, which is a whole
>different class of beast.  
>  
>

Not true.  The QNX gdb can read Neutrino core files from any of our 
targets (ARM, SH, PPC, Mips and i386) on any of our hosts. (Solaris, 
Windows, Linux i386 and native Neutrino i386).

cheers,

Kris

Re: core file not loaded

[Daniel Jacobowitz]

On Wed, Oct 06, 2004 at 01:41:52PM -0400, Paul Koning wrote:
> The other issue (at least when last I looked) is that gdb is only
> willing to handle corefiles for native builds, not for crossbuilds.

This has been mostly fixed.

-- 
Daniel Jacobowitz

RE: core file not loaded

[Xinan Tang]

Hi

  Has anyone implemented "gcore' command in the remote stub without any
OS support?  If I want to support the core file in the remote stub,
where can I find the spec. on the core file (elf) format?

Thanks

--Xinan
  

-----Original Message-----

That's not a core file.  You can probably convert it to a core file,
but you'd also have to teach the BFD and GDB powerpc-eabi support to
recognize it as a powerpc-eabi core file.

A core file is one of several "standard" formats, generated by various
operating systems - lately, a particular kind of ELF object.  Easiest
might be to convert your binary dump to an ELF core file and copy
support from powerpc-linux.

Note that a memory dump isn't enough; for instance, you've lost all
register values.

-- 
Daniel Jacobowitz