Re: [RFC PATCH v1 1/8] Add mseal syscall

[Jeff Xu <jeffxu@google.com>]

On Mon, Oct 16, 2023 at 8:07 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Mon, Oct 16, 2023 at 02:38:20PM +0000, jeffxu@chromium.org wrote:
> > +#ifdef CONFIG_MSEAL
> > +     /*
> > +      * bit masks for seal.
> > +      * need this since vm_flags is full.
> > +      */
> > +     unsigned long vm_seals;         /* seal flags, see mm.h. */
>
> "unsigned long" and yet:
>
> > diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> > index c0cb22cd607d..f574c7dbee76 100644
> > --- a/include/linux/syscalls.h
> > +++ b/include/linux/syscalls.h
> > @@ -802,6 +802,8 @@ asmlinkage long sys_process_mrelease(int pidfd, unsigned int flags);
> >  asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
> >                       unsigned long prot, unsigned long pgoff,
> >                       unsigned long flags);
> > +asmlinkage long sys_mseal(unsigned long start, size_t len, unsigned int types,
> > +                       unsigned int flags);
>
> "unsigned int"?
>
> Why the mis-match?
>
Thanks. Fixed in V2.

> > --- a/include/uapi/linux/mman.h
> > +++ b/include/uapi/linux/mman.h
> > @@ -55,4 +55,10 @@ struct cachestat {
> >       __u64 nr_recently_evicted;
> >  };
> >
> > +#define MM_SEAL_MSEAL                0x1
> > +#define MM_SEAL_MPROTECT     0x2
> > +#define MM_SEAL_MUNMAP               0x4
> > +#define MM_SEAL_MMAP         0x8
> > +#define MM_SEAL_MREMAP               0x10
>
> I think we can use the BIT() macro in uapi .h files now, it is _BITUL().
> Might want to use it here too to make it obvious what is happening.
>
Sure. Will update in V2.

> thanks,
>
> greg k-h