Re: [PATCH 14/15] arch: add split IPC system calls where needed

Arnd Bergmann
2019-01-15T15:01:24Z

On Mon, Jan 14, 2019 at 4:59 AM Michael Ellerman <mpe@ellerman.id.au> wrote:
> Arnd Bergmann <arnd@arndb.de> writes:
> > arch/m68k/kernel/syscalls/syscall.tbl | 11 +++++++++++
> > arch/mips/kernel/syscalls/syscall_o32.tbl | 11 +++++++++++
> > arch/powerpc/kernel/syscalls/syscall.tbl | 12 ++++++++++++
>
> I have some changes I'd like to make to our syscall table that will
> clash with this.
>
> I'll try and send them today.

Ok. Are those for 5.0 or 5.1? If they are intended for 5.0, it would be
nice for me to have a branch based on 5.0-rc1 that I can put
the other patches on top of.

> > diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
> > index db3bbb8744af..1bffab54ff35 100644
> > --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> > +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> > @@ -425,3 +425,15 @@
> > 386 nospu pkey_mprotect sys_pkey_mprotect
> > 387 nospu rseq sys_rseq
> > 388 nospu io_pgetevents sys_io_pgetevents compat_sys_io_pgetevents
> > +# room for arch specific syscalls
> > +392 64 semtimedop sys_semtimedop
> > +393 common semget sys_semget
> > +394 common semctl sys_semctl compat_sys_semctl
> > +395 common shmget sys_shmget
> > +396 common shmctl sys_shmctl compat_sys_shmctl
> > +397 common shmat sys_shmat compat_sys_shmat
> > +398 common shmdt sys_shmdt
> > +399 common msgget sys_msgget
> > +400 common msgsnd sys_msgsnd compat_sys_msgsnd
> > +401 common msgrcv sys_msgrcv compat_sys_msgrcv
> > +402 common msgctl sys_msgctl compat_sys_msgctl
>
> We already have a gap at 366-377 from when we tried to add the split IPC
> calls a few years back.
>
> I guess I don't mind leaving that gap and using the common numbers as
> you've done here.
>
> But it would be good to add a comment pointing out that we have room
> at 366 for more arch specific syscalls as well.

Ah, I missed that. I've added this to my patch now:

index 5c0936d862fc..2ddfba536d5f 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -460,6 +460,7 @@
363 spu switch_endian sys_ni_syscall
364 common userfaultfd sys_userfaultfd
365 common membarrier sys_membarrier
+# 366-377 originally left for IPC, now unused
378 nospu mlock2 sys_mlock2
379 nospu copy_file_range sys_copy_file_range
380 common preadv2 sys_preadv2
compat_sys_preadv2

Arnd