[coldfire-gnu-discuss] Debugging from flash

[Corrin Meyer]

Sorry, I forgot to include the exception frame.  That is actually what I
was trying to look into but it doesn't seem to make sense to me.  The
following GDB session output was from attempting to debug the 'hello
world' program from flash. This program, when run without GDB, runs
fine.  It can be debugged fine by GDB when run from RAM.


(gdb) target remote | m68k-elf-sprite pe: m52235evb Remote debugging
using | m68k-elf-sprite pe: m52235evb
m68k-elf-sprite: Opening P&E USBMultilink port 1 (USB1 : USB-ML-CF REF :
M52230DEMO (PE60))
m68k-elf-sprite: Target reset
0x00000000 in __cs3_interrupt_vector_coldfire ()
(gdb) c
Continuing.

Program received signal SIGTRAP, Trace/breakpoint trap.
0x00000f5e in __cs3_isr_illegal_instruction ()
(gdb) p $sp
$1 = (void *) 0x20007f88
(gdb) x/4xw $sp
0x20007f88:     0x20007fd4      0x40102708      0x00000002
0xfffffffe
(gdb)


This exception frame doesn't seem to make a whole lot of sense to me.

I did make some progress though.  If I manually set $pc = __cs3_reset
and $sp = 0x20008000 and then issue the continue command, it executes as
expected. Also I can add breakpoints if I use 'hbreak' but it doesn't
seem to add hardware breakpoints by default.

Corrin Meyer

> -----Original Message-----
> From: Corrin Meyer [mailto:Corrin.Meyer at dornerworks.com]
> Sent: Monday, September 08, 2008 10:42 AM
> To: coldfire-gnu-discuss at codesourcery.com
> Subject: RE: [coldfire-gnu-discuss] Debugging from flash
> 
> It actually is not a M52235EVB but the ColdFire is configured like a
> M52235EVB.  I have been able to successfully run and debug
applications
> from RAM.  It is just once I go to Flash that I am getting this
problem.
> 
> Corrin Meyer
> 
> > -----Original Message-----
> > From: Daniel Jacobowitz [mailto:dan at codesourcery.com]
> > Sent: Monday, September 08, 2008 9:42 AM
> > To: Corrin Meyer
> > Cc: coldfire-gnu-discuss at codesourcery.com
> > Subject: Re: [coldfire-gnu-discuss] Debugging from flash
> >
> > On Mon, Sep 08, 2008 at 09:21:09AM -0400, Corrin Meyer wrote:
> > > (gdb) target remote | m68k-elf-sprite pe: m52235evb
> >
> > Just checking, is your board actually an M52235EVB or is it
something
> > similar but slightly different?
> >
> > > Program received signal SIGTRAP, Trace/breakpoint trap.
> > > 0x00000e12 in __cs3_isr_illegal_instruction ()
> > > (gdb)
> >
> > At this point, I'd suggest you check the exception frame on the
stack
> > to see what instruction was illegal.
> >
> > > I would expect that after issuing the continue command that the
> program
> > > should execute just as if the board had been booted.  Am I missing
> > > something?
> >
> > Almost the same.  The only difference is that the initialization
> > sequence in the board file is executed first; this is to support
> > programs run from RAM, which may require the memory controller
> > to be initialized first.  But in general the initialization sequence
> > does not cause a problem if executed twice.
> >
> > --
> > Daniel Jacobowitz
> > CodeSourcery