Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935189Ab3DPBFb (ORCPT ); Mon, 15 Apr 2013 21:05:31 -0400 Received: from mail-wg0-f47.google.com ([74.125.82.47]:53552 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934863Ab3DPBF3 (ORCPT ); Mon, 15 Apr 2013 21:05:29 -0400 Date: Tue, 16 Apr 2013 03:05:25 +0200 From: Frederic Weisbecker To: Jiri Olsa Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , "H. Peter Anvin" , Andi Kleen , Oleg Nesterov , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Paul Mackerras , Corey Ashford , Vince Weaver , Stephane Eranian Subject: Re: [PATCH 1/6] signal x86: Propage RF EFLAGS bit throught the signal restore call Message-ID: <20130416010524.GH17561@somewhere.redhat.com> References: <1362940871-24486-1-git-send-email-jolsa@redhat.com> <1362940871-24486-2-git-send-email-jolsa@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1362940871-24486-2-git-send-email-jolsa@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1766 Lines: 55 On Sun, Mar 10, 2013 at 07:41:06PM +0100, Jiri Olsa wrote: > Adding RF EFLAGS bit to be restored on return from signal from > the original register context before the signal was entered. > > This will prevent the RF flag to disappear when returning > from exception due to the signal handler being executed. So that happens if, say, we get a breakpoint exception and then we run a signal handler before returning to the ip that triggered the breakpoint? [...] > --- a/arch/x86/include/asm/sighandling.h > +++ b/arch/x86/include/asm/sighandling.h > @@ -7,10 +7,10 @@ > > #include > > -#define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \ > +#define FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \ > X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \ > X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \ > - X86_EFLAGS_CF) > + X86_EFLAGS_CF | X86_EFLAGS_RF) > > void signal_fault(struct pt_regs *regs, void __user *frame, char *where); > > diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c > index 6956299..9df4c0b 100644 > --- a/arch/x86/kernel/signal.c > +++ b/arch/x86/kernel/signal.c > @@ -43,12 +43,6 @@ > > #include > > -#ifdef CONFIG_X86_32 > -# define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF) > -#else > -# define FIX_EFLAGS __FIX_EFLAGS > -#endif So, I'm a bit confused here. Why was that only hapenning in X86_64? > - > #define COPY(x) do { \ > get_user_ex(regs->x, &sc->x); \ > } while (0) > -- > 1.7.11.7 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/