[PATCH] lib: sbi: fix ctz bug

[Bin Meng]

On Wed, Sep 15, 2021 at 2:51 PM Xiang W <wxjstz at 126.com> wrote:
>
> The original version of ctz will cause an endless loop, if the parameter
> passed in is 0. This commit fixes this bug.
>
> Signed-off-by: Xiang W <wxjstz at 126.com>
> ---
>  lib/sbi/riscv_asm.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/lib/sbi/riscv_asm.c b/lib/sbi/riscv_asm.c
> index 4c24a51..d7b9b2b 100644
> --- a/lib/sbi/riscv_asm.c
> +++ b/lib/sbi/riscv_asm.c
> @@ -213,6 +213,9 @@ static unsigned long ctz(unsigned long x)
>  {
>         unsigned long ret = 0;
>
> +       if (x == 0)
> +               return 8 * sizeof(x);
> +
>         while (!(x & 1UL)) {
>                 ret++;
>                 x = x >> 1;

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>