Re: RTEMS soft reboot

[Matt Rippa <mrippa@gemini.edu>]

Hi Till, Kate -

Thanks for the responses. It turns out the keyboard reset was
not actually causing trouble --that code was never executing. In
fact (for the 2700) no reset of any kind was attempted. The 
stackTrace seems to just have been called for debugging reasons.

Adding vmeUniverseResetBus() works great and now exit perform as 
expected. I've attached a patch, but it still includes the stack 
trace in case whom ever included it still wants it.

If it's ok, I'll request this be added to the 4.10 release on
the rtems site.

Thanks!

-Matt

Till Straumann wrote:
> 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)


--- /tmp/rtems-4.9.1/c/src/lib/libbsp/powerpc/shared/console/reboot.c	2008-10-23 03:45:55.000000000 -1000
+++ reboot.c	2009-01-23 09:16:01.312017000 -1000
@@ -21,5 +21,7 @@
 #endif
 #if defined(mvme2100)
   *(unsigned char*)0xffe00000 |= 0x80;
+#else
+  vmeUniverseResetBus();
 #endif
 } /* bsp_reset */