Re: [PATCH] riscv: Make semihosting configurable for all privilege modes

[Alistair Francis]

On Sat, Aug 13, 2022 at 8:20 PM Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Sat, 13 Aug 2022 at 01:53, Furquan Shaikh <furquan@rivosinc.com> wrote:
> > I ran into a problem when I was testing a project (with a microkernel
> > in M-mode and tasks in U-mode) that uses semihosting for debugging.
> > The semihosting worked fine for M-mode but not in U-mode. As I started
> > digging into this, I realized that this is because qemu restricts
> > semihosting to only M and S modes.
>
> Right. We should fix this by having a generic works-for-all-architectures
> semihosting config knob, because this is not a riscv specific problem,
> and we already have issues with different target architectures
> developing their own solutions to things.

I agree with Peter here. I don't see a strong use case for a RISC-V
specific fine grained control. A user can either enable/disable
semihosting for privilege or usermodes (with Peter's patchset). That
seems like enough configuration options, it is unlikely that someone
will need semihosting only available to S-mode for example.

Alistair

>
> I'll see if I can dig out the half-done patchset I had for this.
>
> thanks
> -- PMM
>