Re: [PATCH for-6.0] hw/timer/renesas_tmr: Add default-case asserts in read_tcnt()

[Peter Maydell]

ping for review?

thanks
-- PMM

On Fri, 19 Mar 2021 at 16:24, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In commit 81b3ddaf8772ec we fixed a use of uninitialized data
> in read_tcnt(). However this change wasn't enough to placate
> Coverity, which is not smart enough to see that if we read a
> 2 bit field and then handle cases 0, 1, 2 and 3 then there cannot
> be a flow of execution through the switch default. Add explicit
> default cases which assert that they can't be reached, which
> should help silence Coverity.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/timer/renesas_tmr.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/hw/timer/renesas_tmr.c b/hw/timer/renesas_tmr.c
> index eed39917fec..d96002e1ee6 100644
> --- a/hw/timer/renesas_tmr.c
> +++ b/hw/timer/renesas_tmr.c
> @@ -146,6 +146,8 @@ static uint16_t read_tcnt(RTMRState *tmr, unsigned size, 
> int ch)
>          case CSS_CASCADING:
>              tcnt[1] = tmr->tcnt[1];
>              break;
> +        default:
> +            g_assert_not_reached();
>          }
>          switch (FIELD_EX8(tmr->tccr[0], TCCR, CSS)) {
>          case CSS_INTERNAL:
> @@ -159,6 +161,8 @@ static uint16_t read_tcnt(RTMRState *tmr, unsigned size, 
> int ch)
>          case CSS_EXTERNAL: /* QEMU doesn't implement this */
>              tcnt[0] = tmr->tcnt[0];
>              break;
> +        default:
> +            g_assert_not_reached();
>          }
>      } else {
>          tcnt[0] = tmr->tcnt[0];
> --
> 2.20.1