From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 24215 invoked from network); 19 May 2021 15:24:30 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 19 May 2021 15:24:30 -0000 Received: (qmail 11809 invoked by uid 550); 19 May 2021 15:24:28 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 11769 invoked from network); 19 May 2021 15:24:27 -0000 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Wed, 19 May 2021 10:22:05 -0500 From: Segher Boessenkool To: Joakim Tjernlund Cc: "npiggin@gmail.com" , "linuxppc-dev@lists.ozlabs.org" , "ldv@altlinux.org" , "mpe@ellerman.id.au" , "musl@lists.openwall.com" , "libc-dev@lists.llvm.org" , "linux-api@vger.kernel.org" Message-ID: <20210519152205.GL10366@gate.crashing.org> References: <20200611081203.995112-1-npiggin@gmail.com> <20210518231331.GA8464@altlinux.org> <9b5ea7059c5a5d4e9ccccd7d73ce2c66b2203f52.camel@infinera.com> <1621410291.c7si38sa9q.astroid@bobo.none> <1621413143.oec64jaci5.astroid@bobo.none> <20210519143836.GJ10366@gate.crashing.org> <11d62aa2488e51ec00fe77f24a1d7cdcc21af0b8.camel@infinera.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11d62aa2488e51ec00fe77f24a1d7cdcc21af0b8.camel@infinera.com> User-Agent: Mutt/1.4.2.3i Subject: [musl] Re: Linux powerpc new system call instruction and ABI On Wed, May 19, 2021 at 03:06:49PM +0000, Joakim Tjernlund wrote: > On Wed, 2021-05-19 at 09:38 -0500, Segher Boessenkool wrote: > > On Wed, May 19, 2021 at 06:42:40PM +1000, Nicholas Piggin wrote: > > > Excerpts from Joakim Tjernlund's message of May 19, 2021 6:08 pm: > > > > I always figured the ppc way was superior. It begs the question if not the other archs should > > > > change instead? > > > > > > It is superior in some ways, not enough to be worth being different. > > > > The PowerPC syscall ABI *requires* using cr0.3 for indicating errors, > > you will have to do that whether you conflate the concepts of return > > code and error indicator or not! > > > > > Other archs are unlikely to change because it would be painful for > > > not much benefit. > > > > Other archs cannot easily change for much the same reason :-) > > Really? I figured you could just add extra error indication in kernel syscall I/F. > Eventually user space could migrate to the new indication. You seem to assume all user space uses glibc, or *any* libc even? This is false. Some programs do system calls directly. Do not break the kernel ABI :-) Segher