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

[Yoshinori Sato]

On Sat, 20 Mar 2021 01:24:58 +0900,
Peter Maydell 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>

Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp>

> ---
>  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
> 

I'm back.
---
Yoshinori Sato