Re: [PATCH 07/30] bsd-user/arm/target_arch_cpu.h: Use force_sig_fault for EXCP_UDEF

[Peter Maydell]

On Sun, 9 Jan 2022 at 16:27, Warner Losh <imp@bsdimp.com> wrote:
>
> Use force_sig_fault to implement unknown opcode. This just uninlines
> that function, so simplify things by using it. Fold in EXCP_NOCP and
> EXCP_INVSTATE, as is done in linux-user.
>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>  bsd-user/arm/target_arch_cpu.h | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/bsd-user/arm/target_arch_cpu.h b/bsd-user/arm/target_arch_cpu.h
> index 905f13aa1b9..996a361e3fe 100644
> --- a/bsd-user/arm/target_arch_cpu.h
> +++ b/bsd-user/arm/target_arch_cpu.h
> @@ -51,18 +51,12 @@ static inline void target_cpu_loop(CPUARMState *env)
>          process_queued_cpu_work(cs);
>          switch (trapnr) {
>          case EXCP_UDEF:
> -            {
> -                /* See arm/arm/undefined.c undefinedinstruction(); */
> -                info.si_addr = env->regs[15];
> -
> -                /* illegal instruction */
> -                info.si_signo = TARGET_SIGILL;
> -                info.si_errno = 0;
> -                info.si_code = TARGET_ILL_ILLOPC;
> -                queue_signal(env, info.si_signo, &info);
> -
> -                /* TODO: What about instruction emulation? */
> -            }
> +        case EXCP_NOCP:
> +        case EXCP_INVSTATE:
> +            /*
> +             * See arm/arm/undefined.c undefinedinstruction();
> +             */
> +            force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->regs[15]);
>              break;

Do you want to keep the TODO comment ?

Either way,
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

(Looks like FreeBSD sends SIGILL/ILL_ILLADR for UNDEF where the PC
is misaligned and we're not in Thumb mode, but that's a pretty oddball
corner case so not really worth emulating.)

thanks
-- PMM