Re: [PATCH] RISC-V: mm: Fix set_satp_mode() for platform not having Sv57

[Palmer Dabbelt]

On Thu, 21 Apr 2022 02:30:05 PDT (-0700), apatel@xxxxxxxxxxxxxxxx wrote:
> Hi Palmer,
>
> On Tue, Apr 12, 2022 at 9:04 AM Anup Patel <apatel@xxxxxxxxxxxxxxxx> wrote:
> > When Sv57 is not available the satp.MODE test in set_satp_mode() will
> > fail and lead to pgdir re-programming for Sv48. The pgdir re-programming
> > will fail as well due to pre-existing pgdir entry used for Sv57 and as
> > a result kernel fails to boot on RISC-V platform not having Sv57.
> >
> > To fix above issue, we should clear the pgdir memory in set_satp_mode()
> > before re-programming.
> >
> > Fixes: 011f09d12052 ("riscv: mm: Set sv57 on defaultly")
> > Reported-by: Mayuresh Chitale <mchitale@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
>
> Can this be considered for 5.18-rcX ?

Sorry, there's a queue but I just say this one at the top and it's super 
simple so I'm going to take it now -- IRC is good to ping this sort of 
stuff.

It's in fixes.

Thanks!

> Regards,
> Anup
>
> > ---
> >  arch/riscv/mm/init.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > index 9535bea8688c..b0793dc0c291 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -718,6 +718,7 @@ static __init void set_satp_mode(void)
> >                 if (!check_l4) {
> >                         disable_pgtable_l5();
> >                         check_l4 = true;
> > +                       memset(early_pg_dir, 0, PAGE_SIZE);
> >                         goto retry;
> >                 }
> >                 disable_pgtable_l4();
> > --
> > 2.25.1