From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>,
"ldv@altlinux.org" <ldv@altlinux.org>,
"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
"libc-dev@lists.llvm.org" <libc-dev@lists.llvm.org>,
"musl@lists.openwall.com" <musl@lists.openwall.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>
Subject: Re: Linux powerpc new system call instruction and ABI
Date: Wed, 19 May 2021 09:38:36 -0500 [thread overview]
Message-ID: <20210519143836.GJ10366@gate.crashing.org> (raw)
In-Reply-To: <1621413143.oec64jaci5.astroid@bobo.none>
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 :-)
> New system calls just should be made to not return
> error numbers.
Which sometimes is a difficult / non-natural / clumsy thing to do.
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: "musl@lists.openwall.com" <musl@lists.openwall.com>,
"ldv@altlinux.org" <ldv@altlinux.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"libc-dev@lists.llvm.org" <libc-dev@lists.llvm.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: Linux powerpc new system call instruction and ABI
Date: Wed, 19 May 2021 09:38:36 -0500 [thread overview]
Message-ID: <20210519143836.GJ10366@gate.crashing.org> (raw)
In-Reply-To: <1621413143.oec64jaci5.astroid@bobo.none>
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 :-)
> New system calls just should be made to not return
> error numbers.
Which sometimes is a difficult / non-natural / clumsy thing to do.
Segher
next prev parent reply other threads:[~2021-05-19 14:43 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 8:12 Linux powerpc new system call instruction and ABI Nicholas Piggin
2020-06-11 8:12 ` Nicholas Piggin
2020-06-11 8:12 ` [PATCH 1/2] powerpc/64s/exception: treat NIA below __end_interrupts as soft-masked Nicholas Piggin
2020-06-11 8:12 ` Nicholas Piggin
2020-07-24 13:25 ` Michael Ellerman
2020-07-24 13:25 ` Michael Ellerman
2020-06-11 8:12 ` [PATCH 2/2] powerpc/64s: system call support for scv/rfscv instructions Nicholas Piggin
2020-06-11 8:12 ` Nicholas Piggin
2020-07-23 6:47 ` Michael Ellerman
2020-07-23 16:48 ` Christophe Leroy
2020-07-23 16:48 ` Christophe Leroy
2020-07-24 10:45 ` Michael Ellerman
2020-07-24 10:45 ` Michael Ellerman
2020-06-11 21:02 ` Linux powerpc new system call instruction and ABI Segher Boessenkool
2020-06-11 21:02 ` Segher Boessenkool
2020-06-14 9:26 ` Nicholas Piggin
2020-06-14 9:26 ` Nicholas Piggin
2021-05-18 23:13 ` Dmitry V. Levin
2021-05-18 23:13 ` Dmitry V. Levin
2021-05-19 2:50 ` Nicholas Piggin
2021-05-19 2:50 ` Nicholas Piggin
2021-05-19 5:01 ` Nicholas Piggin
2021-05-19 5:01 ` Nicholas Piggin
2021-05-21 19:40 ` Matheus Castanho
2021-05-21 19:40 ` Matheus Castanho
2021-05-21 19:52 ` Florian Weimer
2021-05-21 19:52 ` Florian Weimer
2021-05-21 20:00 ` Matheus Castanho
2021-05-21 20:00 ` Matheus Castanho
2021-05-21 20:52 ` Dmitry V. Levin
2021-05-21 20:52 ` Dmitry V. Levin
2021-05-24 12:11 ` Matheus Castanho
2021-05-24 12:11 ` Matheus Castanho
2021-05-24 20:33 ` Matheus Castanho
2021-05-24 20:33 ` Matheus Castanho
2021-05-19 10:24 ` Dmitry V. Levin
2021-05-19 10:24 ` Dmitry V. Levin
2021-05-19 10:59 ` Nicholas Piggin
2021-05-19 10:59 ` Nicholas Piggin
2021-05-19 12:39 ` Tulio Magno Quites Machado Filho
2021-05-19 12:39 ` Tulio Magno Quites Machado Filho
2021-05-19 13:26 ` Dmitry V. Levin
2021-05-19 13:26 ` Dmitry V. Levin
2021-05-19 22:51 ` Nicholas Piggin
2021-05-19 22:51 ` Nicholas Piggin
2021-05-19 23:27 ` Dmitry V. Levin
2021-05-19 23:27 ` Dmitry V. Levin
2021-05-20 2:40 ` Nicholas Piggin
2021-05-20 2:40 ` Nicholas Piggin
2021-05-20 3:06 ` Dmitry V. Levin
2021-05-20 3:06 ` Dmitry V. Levin
2021-05-20 5:12 ` Nicholas Piggin
2021-05-20 5:12 ` Nicholas Piggin
2021-05-19 7:33 ` Joakim Tjernlund
2021-05-19 7:33 ` Joakim Tjernlund
2021-05-19 7:55 ` Nicholas Piggin
2021-05-19 7:55 ` Nicholas Piggin
2021-05-19 8:08 ` Joakim Tjernlund
2021-05-19 8:08 ` Joakim Tjernlund
2021-05-19 8:42 ` Nicholas Piggin
2021-05-19 8:42 ` Nicholas Piggin
2021-05-19 11:12 ` Nicholas Piggin
2021-05-19 11:12 ` Nicholas Piggin
2021-05-19 14:38 ` Segher Boessenkool [this message]
2021-05-19 14:38 ` Segher Boessenkool
2021-05-19 15:06 ` Joakim Tjernlund
2021-05-19 15:06 ` Joakim Tjernlund
2021-05-19 15:22 ` Segher Boessenkool
2021-05-19 15:22 ` Segher Boessenkool
2021-05-19 15:36 ` [musl] " Rich Felker
2021-05-19 15:36 ` Rich Felker
2021-05-19 18:09 ` Joakim Tjernlund
2021-05-19 18:09 ` Joakim Tjernlund
2021-05-19 23:48 ` [musl] " Rich Felker
2021-05-19 23:48 ` Rich Felker
2021-05-20 1:06 ` Dmitry V. Levin
2021-05-20 1:06 ` Dmitry V. Levin
2021-05-20 2:45 ` Nicholas Piggin
2021-05-20 2:45 ` Nicholas Piggin
2021-05-20 2:59 ` Dmitry V. Levin
2021-05-20 2:59 ` Dmitry V. Levin
2021-05-20 7:20 ` Nicholas Piggin
2021-05-20 7:20 ` Nicholas Piggin
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