From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Subject: Re: [PATCH 14/15] arch: add split IPC system calls where needed Date: Mon, 14 Jan 2019 14:40:14 +1100 Message-ID: <87r2df29gh.fsf@concordia.ellerman.id.au> References: <20190110162435.309262-1-arnd@arndb.de> <20190110162435.309262-15-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190110162435.309262-15-arnd@arndb.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Archive: List-Post: To: y2038@lists.linaro.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Cc: dalias@libc.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, catalin.marinas@arm.com, will.deacon@arm.com, linux@dominikbrodowski.net, jcmvbkbc@gmail.com, deepa.kernel@gmail.com, hpa@zytor.com, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, dave@stgolabs.net, deller@gmx.de, x86@kernel.org, linux@armlinux.org.uk, mingo@redhat.com, geert@linux-m68k.org, firoz.khan@linaro.org, mattst88@gmail.com, fenghua.yu@intel.com, Arnd Bergmann , heiko.carstens@de.ibm.com, linux-m68k@lists.linux-m68k.org, ink@jurassic.park.msu.ru, luto@kernel.org, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, monstr@monstr.eu, tony.luck@intel.com, linux-parisc@vger.kernel.org, linux-mips@vger.kernel.org, paul.burton@mips.com, ebiederm@xmission.com, linux-alpha@vger.kernel.org, schwidefsky@de.ibm.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.orgd List-ID: Hi Arnd, Arnd Bergmann writes: > The IPC system call handling is highly inconsistent across architectures, > some use sys_ipc, some use separate calls, and some use both. We also > have some architectures that require passing IPC_64 in the flags, and > others that set it implicitly. > > For the additon of a y2083 safe semtimedop() system call, I chose to only > support the separate entry points, but that requires first supporting > the regular ones with their own syscall numbers. > > The IPC_64 is now implied by the new semctl/shmctl/msgctl system > calls even on the architectures that require passing it with the ipc() > multiplexer. > > I'm not adding the new semtimedop() or semop() on 32-bit architectures, > those will get implemented using the new semtimedop_time64() version > that gets added along with the other time64 calls. > Three 64-bit architectures (powerpc, s390 and sparc) get semtimedop(). > > Signed-off-by: Arnd Bergmann > --- > One aspect here that might be a bit controversial is the use of > the same system call numbers across all architectures, synchronizing > all of them with the x86-32 numbers. With the new syscall.tbl > files, I hope we can just keep doing that in the future, and no > longer require the architecture maintainers to assign a number. > > This is mainly useful for implementers of the C libraries: if > we can add future system calls everywhere at the same time, using > a particular version of the kernel headers also guarantees that > the system call number macro is visible. > --- > 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. > 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. But would be good to add a comment pointing out that we have room there for arch specific syscalls as well. cheers