Re: [PATCH] spi: rockchip: avoid objtool warning

[Emil Renner Berthing <kernel@xxxxxxxx>]

On Thu, 25 Feb 2021 at 13:55, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> Building this file with clang leads to a an unreachable code path
> causing a warning from objtool:
>
> drivers/spi/spi-rockchip.o: warning: objtool: rockchip_spi_transfer_one()+0x2e0: sibling call from callable instruction with modified stack frame
>
> Use BUG() instead of unreachable() to avoid the undefined behavior
> if it does happen.
>
> Fixes: 65498c6ae241 ("spi: rockchip: support 4bit words")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Acked-by: Emil Renner Berthing <kernel@xxxxxxxx>

> ---
>  drivers/spi/spi-rockchip.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
> index 936ef54e0903..972beac1169a 100644
> --- a/drivers/spi/spi-rockchip.c
> +++ b/drivers/spi/spi-rockchip.c
> @@ -521,7 +521,7 @@ static void rockchip_spi_config(struct rockchip_spi *rs,
>                  * ctlr->bits_per_word_mask, so this shouldn't
>                  * happen
>                  */
> -               unreachable();
> +               BUG();
>         }
>
>         if (use_dma) {
> --
> 2.29.2
>