[[PATCH v2]] riscv: add backtrace support

[Leo Liang]

On Tue, Sep 05, 2023 at 01:12:53PM +0100, Ben Dooks wrote:
> When debugging, it is useful to have a backtrace to find
> out what is in the call stack as the previous function (RA)
> may not have been the culprit.
> 
> Since this adds size to the build, do not add it by default
> and avoid putting it in the SPL build if not needed.
> 
> Signed-off-by: Ben Dooks <ben.dooks at codethink.co.uk>
> ---
> v2:
>   - back to codethink email as sifive account is now gone
>   - add option to build SPL with frame pointer
>     (as suggested by Bo Gan <ganboing at gmail.com>
> ---
>  arch/riscv/Kconfig          | 20 ++++++++++++++++++++
>  arch/riscv/Makefile         |  4 ++++
>  arch/riscv/cpu/start.S      |  1 +
>  arch/riscv/lib/interrupts.c | 35 +++++++++++++++++++++++++++++++++++
>  4 files changed, 60 insertions(+)

Tested-by: Leo Yu-Chi Liang <ycliang at andestech.com>