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RE: Multi thread Debugging
- To: 'Jonathan Larmour' <jlarmour at redhat dot co dot uk>, Fabrice Gautier <Fabrice_Gautier at sdesigns dot com>
- Subject: RE: [ECOS] Multi thread Debugging
- From: Fabrice Gautier <Fabrice_Gautier at sdesigns dot com>
- Date: Wed, 30 Aug 2000 16:37:59 -0700
- Cc: "Ecos-List (E-mail)" <ecos-discuss at sourceware dot cygnus dot com>
> -----Original Message-----
> From: Jonathan Larmour [mailto:jlarmour@redhat.co.uk]
> Subject: Re: [ECOS] Multi thread Debugging
>
>
>
> The stack_ptr member is there for a different purpose than
> saved_context.
> saved_context is for GDB debugging purposes only and provides the full
> context. AFAIK interrupt_end is the only place that stores
> the context in
> saved_context.
In fact I've seen that when saved_context member is NULL, the stack_ptr is
used instead.
> This is interesting - it's not clear to me either how
> saved_context is set
> if threads get rescheduled for any reason other than an interrupt.
It is not set at all. But get_saved_context get the registers from
stack_ptr.
> Is this a bug?
It doesn't seem
> I wouldn't have thought this would have caused a problem on the scale
> Fabrice is seeing at any rate.
The problem may be elsewhere.
May be here: (Warning, this is i386 PC specific stuff now)
void hal_get_gdb_registers(target_register_t * d, HAL_SavedRegisters * s)
{
int i ;
for (i = 0; i < NUMREGS; i++)
d[i] = hal_pc_trap_registers[i] ;
}
This is seen in hal/i386/pc/current/src/plf_stub.c. Note how this function
does not use the 's' parameter while all we need is in there. This is called
in dbg_getthreadreg and 's' would be either saved_context or stack_ptr.
I found another version of this function in
hal/i386/arch/current/src/i386_stub.c
#if 0
void hal_get_gdb_registers(target_register_t * d, HAL_SavedRegisters * s)
{
d[ESP] = s->esp ;
d[ESP] = s->esp ;
d[EBP] = s->ebp ;
d[EBX] = s->ebx ;
d[ESI] = s->esi ;
d[EDI] = s->edi ;
d[PC] = s->eip ;
}
#endif
This one looks better, but unfortunately there is no s->eip. The
HAL_SavedRegister doesn't have one. Unfortunate.
If someone know why this version has been discarded and what the other is
intented to do it sould be fun.
Thanks
A+
--
Fabrice Gautier
fabrice_gautier@sdesigns.com