Re: [PATCH 2/3] gdb/arm: Fetch initial sp value prior to compare

[Christophe Lyon <christophe.lyon@arm.com>]

Hi,

On 5/16/22 15:59, Yvan Roux via Gdb-patches wrote:
> For Arm Cortex-M33 with security extensions, there are 4 different
> stacks 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 initla sp register needs to be fetched to

Typo: "initial"

> perform this comparison.
> 
> Signed-off-by: Torbj�rn SVENSSON <torbjorn.svensson@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 c37254c2ce1..4aa277f5bc8 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);

With such simple fixes, I always wonder "how did that somehow worked so 
far?". Can you describe the broken scenario fixed by this patch?

Thanks,

Christophe

>   
>     if (tdep->have_sec_ext)
>       {