Re: [PATCH 3/3] linux-user/aarch64: Add ESR signal frame for PACFAIL

[Peter Maydell]

On Tue, 22 Aug 2023 at 18:02, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> The PACFAIL fault uses ILL_ILLOPN and includes ESR.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/aarch64/cpu_loop.c |  7 ++++++-
>  linux-user/aarch64/signal.c   |  6 ++++++
>  tests/tcg/aarch64/pauth-2.c   | 25 ++++++++++++++++++++++++-
>  3 files changed, 36 insertions(+), 2 deletions(-)
>
> diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
> index 22c9789326..5af17e8724 100644
> --- a/linux-user/aarch64/cpu_loop.c
> +++ b/linux-user/aarch64/cpu_loop.c
> @@ -110,7 +110,12 @@ void cpu_loop(CPUARMState *env)
>              /* just indicate that signals should be handled asap */
>              break;
>          case EXCP_UDEF:
> -            force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->pc);
> +            /* See kernel's do_el0_fpac, and our need_save_esr(). */
> +            if (syn_get_ec(env->exception.syndrome) == EC_PACFAIL) {
> +                force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN, env->pc);
> +            } else {
> +                force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->pc);
> +            }
>              break;
>          case EXCP_PREFETCH_ABORT:
>          case EXCP_DATA_ABORT:
> diff --git a/linux-user/aarch64/signal.c b/linux-user/aarch64/signal.c
> index b2280fa9e3..bcdd796cc2 100644
> --- a/linux-user/aarch64/signal.c
> +++ b/linux-user/aarch64/signal.c
> @@ -582,6 +582,7 @@ static bool need_save_esr(target_siginfo_t *info, 
> CPUARMState *env)
>  {
>      int sig = info->si_signo;
>      int type = info->si_code >> 16;
> +    int code = info->si_code & 0xffff;
>
>      if (type != QEMU_SI_FAULT) {
>          return false;
> @@ -592,6 +593,11 @@ static bool need_save_esr(target_siginfo_t *info, 
> CPUARMState *env)
>          return true;
>      }
>
> +    /* See arch/arm64/kernel/traps.c, do_el0_fpac, and our cpu_loop(). */
> +    if (sig == TARGET_SIGILL && code == TARGET_ILL_ILLOPN) {
> +        return true;
> +    }

This works, but we'll need to do something else if the kernel adds
some other fault later that is reported as ILLOPN but without
an ESR record...

> +
>      return false;
>  }

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

thanks
-- PMM