From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42708C31E45 for ; Tue, 11 Jun 2019 20:42:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B6C021852 for ; Tue, 11 Jun 2019 20:36:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406156AbfFKUgZ (ORCPT ); Tue, 11 Jun 2019 16:36:25 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:43875 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391943AbfFKUgY (ORCPT ); Tue, 11 Jun 2019 16:36:24 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1hanVC-0004lG-Tk; Tue, 11 Jun 2019 14:36:18 -0600 Received: from ip72-206-97-68.om.om.cox.net ([72.206.97.68] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1hanVA-0006GI-BF; Tue, 11 Jun 2019 14:36:18 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Arseny Maslennikov Cc: Greg Kroah-Hartman , Jiri Slaby , Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org, "Vladimir D . Seleznev" , References: <20190605081906.28938-1-ar@cs.msu.ru> <20190605081906.28938-2-ar@cs.msu.ru> Date: Tue, 11 Jun 2019 15:36:00 -0500 In-Reply-To: <20190605081906.28938-2-ar@cs.msu.ru> (Arseny Maslennikov's message of "Wed, 5 Jun 2019 11:19:00 +0300") Message-ID: <87o933507j.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1hanVA-0006GI-BF;;;mid=<87o933507j.fsf@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=72.206.97.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/3P7RQue3RXfD0vg4lwaqD053joFTXlMY= X-SA-Exim-Connect-IP: 72.206.97.68 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 1/7] signal.h: Define SIGINFO on all architectures X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arseny Maslennikov writes: > This complementary patch defines SIGINFO as a synonym for SIGPWR > on every architecture supported by the kernel. > The particular signal number chosen does not really matter and is only > required for the related tty functionality to work properly, > so if it does not suite expectations, any suggestions are warmly > welcome. > > SIGPWR looks like a nice candidate for this role, because it is > defined on every supported arch; it is currently only used to inform > PID 1 of power failures, and daemons that care about low-level > events do not tend to have a controlling terminal. > > However, on sparcs SIGPWR is a synonym for SIGLOST, a signal unique > to that architecture, with a narrow set of intended uses that do not > combine well with interactively requesting status. > SIGLOST is not used by any kernel code at the moment. > I'm not sure there is a more reasonable alternative right now. Is the name SIGINFO already well established. It just is a little bit confusing with struct siginfo. At least on x86 it looks like we have signals 32 and 33 that are reserved and not used for anything. Is there a reason you have not picked one of those? Also should this be a realtime signal with signal information or a non-realtime signal? I don't expect there is much to encode except that the user is asking for information. I half wonder if it could be done as a different si_code to SIGWINCH. But of course that doesn't work because it is not a real time signal so does not queue more than one siginfo. (Sigh). I just would like to see that we have a clear concept of how this new signal plays into all of the signal handling bits. Added linux-api because this is fundamentally extending the linux-api, and we probably want man-page updates etc. Eric > > Signed-off-by: Arseny Maslennikov > --- > arch/arm/include/uapi/asm/signal.h | 1 + > arch/h8300/include/uapi/asm/signal.h | 1 + > arch/ia64/include/uapi/asm/signal.h | 1 + > arch/m68k/include/uapi/asm/signal.h | 1 + > arch/mips/include/uapi/asm/signal.h | 1 + > arch/parisc/include/uapi/asm/signal.h | 1 + > arch/powerpc/include/uapi/asm/signal.h | 1 + > arch/s390/include/uapi/asm/signal.h | 1 + > arch/sparc/include/uapi/asm/signal.h | 2 ++ > arch/x86/include/uapi/asm/signal.h | 1 + > arch/xtensa/include/uapi/asm/signal.h | 1 + > include/uapi/asm-generic/signal.h | 1 + > 12 files changed, 13 insertions(+) > > diff --git a/arch/arm/include/uapi/asm/signal.h b/arch/arm/include/uapi/asm/signal.h > index 9b4185ba4f8a..b80b53a17267 100644 > --- a/arch/arm/include/uapi/asm/signal.h > +++ b/arch/arm/include/uapi/asm/signal.h > @@ -50,6 +50,7 @@ typedef unsigned long sigset_t; > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/arch/h8300/include/uapi/asm/signal.h b/arch/h8300/include/uapi/asm/signal.h > index e15521037348..7a2b783af22b 100644 > --- a/arch/h8300/include/uapi/asm/signal.h > +++ b/arch/h8300/include/uapi/asm/signal.h > @@ -50,6 +50,7 @@ typedef unsigned long sigset_t; > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/arch/ia64/include/uapi/asm/signal.h b/arch/ia64/include/uapi/asm/signal.h > index aa98ff1b9e22..b4c98cb17165 100644 > --- a/arch/ia64/include/uapi/asm/signal.h > +++ b/arch/ia64/include/uapi/asm/signal.h > @@ -45,6 +45,7 @@ > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > /* signal 31 is no longer "unused", but the SIGUNUSED macro remains for backwards compatibility */ > #define SIGUNUSED 31 > diff --git a/arch/m68k/include/uapi/asm/signal.h b/arch/m68k/include/uapi/asm/signal.h > index 915cc755a184..a0b4e4108cb8 100644 > --- a/arch/m68k/include/uapi/asm/signal.h > +++ b/arch/m68k/include/uapi/asm/signal.h > @@ -50,6 +50,7 @@ typedef unsigned long sigset_t; > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/arch/mips/include/uapi/asm/signal.h b/arch/mips/include/uapi/asm/signal.h > index 53104b10aae2..975a6f0d3b0b 100644 > --- a/arch/mips/include/uapi/asm/signal.h > +++ b/arch/mips/include/uapi/asm/signal.h > @@ -43,6 +43,7 @@ typedef unsigned long old_sigset_t; /* at least 32 bits */ > #define SIGCHLD 18 /* Child status has changed (POSIX). */ > #define SIGCLD SIGCHLD /* Same as SIGCHLD (System V). */ > #define SIGPWR 19 /* Power failure restart (System V). */ > +#define SIGINFO SIGPWR /* Keyboard status request (4.2 BSD). */ > #define SIGWINCH 20 /* Window size change (4.3 BSD, Sun). */ > #define SIGURG 21 /* Urgent condition on socket (4.2 BSD). */ > #define SIGIO 22 /* I/O now possible (4.2 BSD). */ > diff --git a/arch/parisc/include/uapi/asm/signal.h b/arch/parisc/include/uapi/asm/signal.h > index d38563a394f2..fe2e00d590ac 100644 > --- a/arch/parisc/include/uapi/asm/signal.h > +++ b/arch/parisc/include/uapi/asm/signal.h > @@ -22,6 +22,7 @@ > #define SIGUSR2 17 > #define SIGCHLD 18 > #define SIGPWR 19 > +#define SIGINFO SIGPWR > #define SIGVTALRM 20 > #define SIGPROF 21 > #define SIGIO 22 > diff --git a/arch/powerpc/include/uapi/asm/signal.h b/arch/powerpc/include/uapi/asm/signal.h > index 85b0a7aa43e7..e7f3885905b4 100644 > --- a/arch/powerpc/include/uapi/asm/signal.h > +++ b/arch/powerpc/include/uapi/asm/signal.h > @@ -53,6 +53,7 @@ typedef struct { > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/arch/s390/include/uapi/asm/signal.h b/arch/s390/include/uapi/asm/signal.h > index 9a14a611ed82..12ee62987971 100644 > --- a/arch/s390/include/uapi/asm/signal.h > +++ b/arch/s390/include/uapi/asm/signal.h > @@ -58,6 +58,7 @@ typedef unsigned long sigset_t; > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/arch/sparc/include/uapi/asm/signal.h b/arch/sparc/include/uapi/asm/signal.h > index ff9505923b9a..b655163198bb 100644 > --- a/arch/sparc/include/uapi/asm/signal.h > +++ b/arch/sparc/include/uapi/asm/signal.h > @@ -71,6 +71,8 @@ > #define SIGWINCH 28 > #define SIGLOST 29 > #define SIGPWR SIGLOST > +/* XXX: is it OK for SIGINFO to collide with LOST? */ > +#define SIGINFO SIGPWR > #define SIGUSR1 30 > #define SIGUSR2 31 > > diff --git a/arch/x86/include/uapi/asm/signal.h b/arch/x86/include/uapi/asm/signal.h > index e5745d593dc7..1539bb28826c 100644 > --- a/arch/x86/include/uapi/asm/signal.h > +++ b/arch/x86/include/uapi/asm/signal.h > @@ -55,6 +55,7 @@ typedef unsigned long sigset_t; > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/arch/xtensa/include/uapi/asm/signal.h b/arch/xtensa/include/uapi/asm/signal.h > index 005dec5bfde4..d644234305de 100644 > --- a/arch/xtensa/include/uapi/asm/signal.h > +++ b/arch/xtensa/include/uapi/asm/signal.h > @@ -65,6 +65,7 @@ typedef struct { > #define SIGPOLL SIGIO > /* #define SIGLOST 29 */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31 > > diff --git a/include/uapi/asm-generic/signal.h b/include/uapi/asm-generic/signal.h > index 5c716a952cbe..9f9a1db0d43c 100644 > --- a/include/uapi/asm-generic/signal.h > +++ b/include/uapi/asm-generic/signal.h > @@ -43,6 +43,7 @@ > #define SIGLOST 29 > */ > #define SIGPWR 30 > +#define SIGINFO SIGPWR > #define SIGSYS 31 > #define SIGUNUSED 31