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Re: exception when calling reset_platform
On Friday, 14. June 2002 14:05, Iztok Zupet wrote:
> 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
RAM is mapped to 0x0 and the size is 0x200000. The function reset_platform
should be and is in this array (0x20394).
Roland
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