Re: [ECOS] exception when calling reset_platform

[Iztok Zupet <iz@vsr.si>]

On Friday 14 June 2002 12:45, Roland Caßebohm wrote:
> On Thursday, 13. June 2002 19:16, Iztok Zupet wrote:
> > On Thursday 13 June 2002 18:20, Roland Caßebohm wrote:
> > > Hi,
> > >
> > > my ARM7TDMI (SNDS100 Board) makes an abort prefetch exception when the
> > > application calls reset_platform().
> > >
> > > I added two nop's because I thought the processor prefetches the
> > > init_done value, but this doesn't help:
> > >
> > > ----------
> > >         .global reset_platform
> > >         .type   reset_platform,function
> > > reset_platform:
> > > #ifdef CYGSEM_HAL_ROM_MONITOR
> > >         // initialize CPSR (machine state register)
> > >         mov
> > > r0,#(CPSR_IRQ_DISABLE|CPSR_FIQ_DISABLE|CPSR_SUPERVISOR_MODE) msr
> > > cpsr,r0
> > >         b       warm_reset
> > > #else
> > >         mov     r0,#0
> > >         mov     pc,r0           // Jump to reset vector
> > >         //roland
> > >         mov     r0,r0           // nop
> > >         mov     r0,r0           // nop
> > > #endif
> > >
> > > init_done:
> > >         .long   0xDEADB00B
> > > ----------
> > >
> > > Does anybody know what's wrong?
> > >
> > > Roland
> >
> > Hi:
> >
> >   Looks like that the abort prefetch hapens somewhere else, not in the
> > code You've sent. Take a look at the reset vector and the code that
> > executes there ( if it is in RAM). It may be corrupt for some reason.
> > Anyhow, can You figure out the address of the exeption?
> >
> > iz
>
> The exception seems to be at 0x31638:
>
> void vs_reboot(void)
> {
>
>     ...
>
>    31638:       ebffbb55        bl      20394 <reset_platform>
> }
>    3163c:       e91ba800        ldmdb   r11, {r11, sp, pc}

Strange. Since the abort prefetch happens here (it happens only beacuse of the 
ABORT signal asserted) it means that <reset_platform> is no longer in valid 
memory that can be reached by cpu. What kind of memory mapping do You have? 
Take a look at the linker xxx.ldi script in the platform/hal directory if 
they if it's correct for  Your memory layout.

iz

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