Re: RTEMS soft reboot

[Till Straumann <strauman@slac.stanford.edu>]

Matt Rippa wrote:
> Running 'exit' on an RTEMS ioc I get a stack trace. Is exit the 
> intended mechanism for a soft reboot?
Well - 'exit' should bring you back to the point where you
started RTEMS. However, this is not really possible on all
boards because the environment that booted RTEMS may
have been destroyed (in your case, RTEMS overwrites
critical memory that was used by PPCBug) and in this case
a hard reset may be required (IIRC, 'exit' should in these
cases do that for you so you may have encountered a bug).

Different BSPs used to have their own API to reset the board
(PPC/shared boards used to call this rtemsReboot(), IIRC)
but, again IIRC, this should have been made more consistent
(don't recall if this happened before or after forking 4.9) and
renamed 'bsp_reset()' across multiple architectures/boards.

Now that I write all this I believe I remember that the old
motorola BSP (mvme2300..2700) indeed has a bug; it tries
to reset via the KBD controller and (again IIRC) that doesn't
work. If it did, rtemsReboot()/bsp_reset() or 'exit()' should both
do the job...

You should be able to reset the board via a VME sysreset
(vmeUniverseResetBus())

-- T.
> I've shown gdb output below. This is running on an MVME-2700.
>
> Thanks,
> -Matt
>
> EPICS 3.14.10 /RTEMS 4.9.1
> ------
> 10.1.5.253> exit
> Printing a stack trace for your convenience :-)
>
> 0x0011A8E0--> 0x0010F55C--> 0x0010A888--> 0x0010A76C--> 0x0000322C
>
>
> gdb shows:
> (gdb) x 0x0000322C
>
> 0x322c <enter_C_code+68>:       0x4800004d
>
> (gdb)
>
> 0x3230 <MMUon>: 0x7c0000a6
>
> (gdb)
>
> 0x3234 <MMUon+4>:       0x6000a972
>
> (gdb)
>
> 0x3238 <MMUon+8>:       0x68008940
>
> (gdb)
>
> 0x323c <MMUon+12>:      0x7d6802a6
>
> (gdb)
>
> 0x3240 <MMUon+16>:      0x7d7a03a6
>
> (gdb)
>
> 0x3244 <MMUon+20>:      0x7c1b03a6
>
> (gdb)
>
> 0x3248 <MMUon+24>:      0x7c0004ac
>
> (gdb)
>
> 0x324c <MMUon+28>:      0x4c00012c
>
> (gdb)
>
> 0x3250 <MMUon+32>:      0x4c000064
>
> (gdb)
>
> 0x3254 <MMUoff>:        0x7c0000a6
>
> (gdb)
>
> 0x3258 <MMUoff+4>:      0x60000070
>
> (gdb)
> 0x325c <MMUoff+8>:      0x7d6802a6
> (gdb)
> 0x3260 <MMUoff+12>:     0x68000030
> (gdb)
> 0x3264 <MMUoff+16>:     0x7d7a03a6
> (gdb)
> 0x3268 <MMUoff+20>:     0x7c1b03a6
> (gdb)
> 0x326c <MMUoff+24>:     0x7c0004ac
> (gdb)
> 0x3270 <MMUoff+28>:     0x4c00012c
> (gdb)
> 0x3274 <MMUoff+32>:     0x4c000064
> (gdb)
> 0x3278 <_return_to_ppcbug>:     0x7fc802a6
> (gdb)