From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [PATCH 3/8] signal/sparc: Document a conflict with SI_USER with SIGFPE Date: Fri, 30 Jun 2017 13:13:40 -0500 Message-ID: <8737ahwdgr.fsf@xmission.com> References: <87efu22set.fsf@xmission.com> <20170630123906.8865-3-ebiederm@xmission.com> <20170630.124505.736865959393416284.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170630.124505.736865959393416284.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> (David Miller's message of "Fri, 30 Jun 2017 12:45:05 -0400 (EDT)") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: David Miller Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, avagin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org, greg-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, xemul-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org, oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, gorcunov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, w@1wt.eu, avagin-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org List-Id: linux-api@vger.kernel.org David Miller writes: > From: "Eric W. Biederman" > Date: Fri, 30 Jun 2017 07:39:01 -0500 > >> diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h >> index 2d9b79ccaa50..6bc5c677e92f 100644 >> --- a/arch/sparc/include/uapi/asm/siginfo.h >> +++ b/arch/sparc/include/uapi/asm/siginfo.h >> @@ -17,6 +17,11 @@ >> #define SI_NOINFO 32767 /* no information in siginfo_t */ >> >> /* >> + * SIGFPE si_codes >> + */ >> +#define FPE_FIXME (__SI_FAULT|0) /* Broken dup of SI_USER */ >> + >> +/* >> * SIGEMT si_codes >> */ >> #define EMT_TAGOVF (__SI_FAULT|1) /* tag overflow */ > > It's one thing to say FIXME in a comment in a kernel local header or > C file. > > It's quite another to put this into the name of a macro which has > visibility in the global user compilation namespace. > > I don't think you should really do that. Good point. Sigh. It almost fits because we did do something off in the uapi exported to userspace and we don't have a header file definition for that case. Still. At this point arch/sparc/include/asm/siginfo.h is a better fit for that definition. I will respin and fix that. I wish I knew what would make a better default floating point si_code on sparc. Using 0 aka SI_USER is doesn't fit at all. Sigh. Unfortunately I don't know the architecture well enough to even guess what is going on in do_fpe_common when when no bits in fsr are set. Any suggests for a better fix than just documenting that linux does something weird and ill advised here? Eric