This seems reasonable to me. The particular bit used isn't so important from my perspective. I can't think of a way this would break backward compatibility or such. So: Reviewed-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx> On Fri, May 21, 2021 at 3:13 PM Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> wrote: > > To introduce VM_SHADOW_STACK as VM_HIGH_ARCH_BIT (37), and make all > VM_HIGH_ARCH_BITs stay together, move VM_UFFD_MINOR_BIT from 37 to 38. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> > Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx> > Cc: Peter Xu <peterx@xxxxxxxxxx> > Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > --- > include/linux/mm.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index c274f75efcf9..923f89b9f1b5 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -373,7 +373,7 @@ extern unsigned int kobjsize(const void *objp); > #endif > > #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR > -# define VM_UFFD_MINOR_BIT 37 > +# define VM_UFFD_MINOR_BIT 38 > # define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */ > #else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ > # define VM_UFFD_MINOR VM_NONE > -- > 2.21.0 >
