Re: [PATCH v2 1/8] linux-user/nios2: Hoist pc advance to the top of EXCP_TRAP

[Peter Maydell]

On Fri, 25 Mar 2022 at 19:52, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Note that this advance *should* be done by the translator, as
> that's the pc value that's supposed to be generated by hardware.
> However, that's a much larger change across sysemu as well.
>
> In the meantime, produce the correct PC for any signals raised
> by the trap instruction.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/nios2/cpu_loop.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/linux-user/nios2/cpu_loop.c b/linux-user/nios2/cpu_loop.c
> index 1e93ef34e6..2768ae61dd 100644
> --- a/linux-user/nios2/cpu_loop.c
> +++ b/linux-user/nios2/cpu_loop.c
> @@ -40,6 +40,12 @@ void cpu_loop(CPUNios2State *env)
>              break;
>
>          case EXCP_TRAP:
> +            /*
> +             * TODO: This advance should be done in the translator, as
> +             * hardware produces an advanced pc as part of all exceptions.
> +             */
> +            env->regs[R_PC] += 4;
> +

You need to rewind again for the TRAP_BRKPT case, as the
kernel does fp->ea -= 4 in breakpoint_c().

Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM