Re: [PATCH 1/3] gdb/arm: Fetch initial sp value prior to compare

[Yvan Roux <yvan.roux@foss.st.com>]

On Wed, Jun 15, 2022 at 09:39:21AM +0100, Luis Machado wrote:
> On 6/14/22 15:59, Yvan Roux wrote:
> > For Arm Cortex-M33 with security extensions, there are 4 different
> > stack pointers (msp_s, msp_ns, psp_s, psp_ns).  In order to
> > identify the active one, compare the values of the different
> > stacks. The value of the initial sp register needs to be fetched to
> > perform this comparison.
> > 
> > Signed-off-by: Torbj�rn SVENSSON <torbjorn.svensson@foss.st.com>
> > Signed-off-by: Yvan Roux <yvan.roux@foss.st.com>
> > ---
> >   gdb/arm-tdep.c | 1 +
> >   1 file changed, 1 insertion(+)
> > 
> > diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
> > index 456649afdaa..1df57f5b5c8 100644
> > --- a/gdb/arm-tdep.c
> > +++ b/gdb/arm-tdep.c
> > @@ -341,6 +341,7 @@ arm_cache_init (struct arm_prologue_cache *cache, struct frame_info *frame)
> >     arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
> >     arm_cache_init (cache, gdbarch);
> > +  cache->sp = get_frame_register_unsigned (frame, ARM_SP_REGNUM);
> >     if (tdep->have_sec_ext)
> >       {
> 
> Does that mean that before this patch the value of cache->sp was uninitialized?

Yes, what Torbjorn found is that arm_prologue_cache->sp value was 0x0 due to
lack of initialization.

-- 
Y.