[PATCH] lib: sbi: fix ctz bug

[Anup Patel]

On Wed, Sep 22, 2021 at 1:26 PM Anup Patel <anup at brainfault.org> wrote:
>
> On Wed, Sep 15, 2021 at 1:02 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >
> > 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>
>
> Looks good to me.
>
> Reviewed-by: Anup Patel <anup.patel at wdc.com>

Applied this to the riscv/opensbi repo as well.

Regards,
Anup

>
> Regards,
> Anup
>
> >
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