Re: [PATCH] riscv: read-only pages should not be writable

[Heinrich Schuchardt <heinrich.schuchardt@xxxxxxxxxxxxx>]

On 5/28/22 11:13, Ard Biesheuvel wrote:
> On Sat, 28 May 2022 at 03:41, Heinrich Schuchardt
> <heinrich.schuchardt@xxxxxxxxxxxxx> wrote:
> > If EFI pages are marked as read-only,
> > we should remove the _PAGE_WRITE flag.
> >
> > The current code overwrites an unused value.
> >
> > Fixes: b91540d52a08b ("RISC-V: Add EFI runtime services")
> > Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@xxxxxxxxxxxxx>
> > ---
> >   arch/riscv/kernel/efi.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c
> > index 024159298231..1aa540350abd 100644
> > --- a/arch/riscv/kernel/efi.c
> > +++ b/arch/riscv/kernel/efi.c
> > @@ -65,7 +65,7 @@ static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)
> >
> >          if (md->attribute & EFI_MEMORY_RO) {
> >                  val = pte_val(pte) & ~_PAGE_WRITE;
> > -               val = pte_val(pte) | _PAGE_READ;
> > +               val |= _PAGE_READ;
> >                  pte = __pte(val);
> >          }
> >          if (md->attribute & EFI_MEMORY_XP) {
> > --
> > 2.36.1
>
> Thanks Heinrich
>
> Queued in efi/urgent.

I guess this should also be down-ported to 5.15 and 5.10.

Best regards

Heinrich