From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Morse Subject: Re: [PATCH 1/3] signal: Add FPE_FLTUNK si_code for undiagnosable fp exceptions Date: Thu, 22 Feb 2018 12:14:17 +0000 Message-ID: <5A8EB419.1020508@arm.com> References: <1519228960-10883-1-git-send-email-Dave.Martin@arm.com> <1519228960-10883-2-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1519228960-10883-2-git-send-email-Dave.Martin@arm.com> 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 To: Dave Martin Cc: linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Will Deacon , "Eric W. Biederman" , Catalin Marinas , linux-arm-kernel@lists.infradead.org List-Id: linux-api@vger.kernel.org Hi Dave, On 21/02/18 16:02, Dave Martin wrote: > Some architectures cannot always report accurately what kind of > floating-point exception triggered a floating-point exception trap. > > This can occur with fp exceptions occuring on lanes in a vector (Nit: occurring) > instruction on arm64 for example. > > Rather than have every architecture come up with its own way of > descrbing such a condition, this patch adds a common FPE_FLTUNK do (Nits: describing; 'to report') > report that an fp exception caused a trap but we cannot be certain > which kind of fp exception it was. > diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h > index 85dc965..10304de 100644 > --- a/include/uapi/asm-generic/siginfo.h > +++ b/include/uapi/asm-generic/siginfo.h > @@ -229,7 +229,8 @@ typedef struct siginfo { > # define __FPE_INVASC 12 /* invalid ASCII digit */ > # define __FPE_INVDEC 13 /* invalid decimal digit */ > #endif > -#define NSIGFPE 13 > +#define FPE_FLTUNK 14 /* undiagnosed floating-point exception */ > +#define NSIGFPE 14 It looks like x86's compat relies on this value not changing: | arch/x86/kernel/signal_compat.c: BUILD_BUG_ON(NSIGFPE != 13); | include/uapi/asm-generic/siginfo.h:#define NSIGFPE 13 (from v4.16-rc2) Thanks, James