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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 83ECFC433E0 for ; Tue, 2 Mar 2021 16:39:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B9E964F20 for ; Tue, 2 Mar 2021 16:39:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1839598AbhCBQhK (ORCPT ); Tue, 2 Mar 2021 11:37:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346101AbhCBOLU (ORCPT ); Tue, 2 Mar 2021 09:11:20 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8354DC061788 for ; Tue, 2 Mar 2021 05:59:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=EubBMfIVizTxskJSZHHLt40+i8CYcZ/ie+sARr952Mc=; b=soD3rL9r9fPNuyFKOCHKxq6JUQ t4RV205rxrd8sVeBNVJZ1kflhqO0cXAS5YPuVNg7qVBYVzKENLijoW8no3eJUuUK0EgYU3mJ8e4iL VwdR57WDfV8fN2njkrwVDk+SUi/MgQWewsZUP9RupFV1pQXntgpp+bTTUisu4Cbv5eLwNUd+9AQ/i J+BfEDfdYkW5VHlT0zl6AZnXNAjRQ8TkuZlpQLgvUQDvn0jNOV4p3t/FG8JBPzQwt5B7aEuuE47zz ltGY2XuYJ3XJ26G0blSCYrR67QDQDWY4JRVOjPieF8Yy/C9j2Whl/oS7geSINgUcxuDPosfU6ZmRP 7GZnBOcw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lH5XG-00HDmS-UG; Tue, 02 Mar 2021 13:58:06 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 2B83330018A; Tue, 2 Mar 2021 14:58:01 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 13C692027C1AA; Tue, 2 Mar 2021 14:58:01 +0100 (CET) Date: Tue, 2 Mar 2021 14:58:01 +0100 From: Peter Zijlstra To: Masami Hiramatsu Cc: Andy Lutomirski , Ingo Molnar , Oleg Nesterov , LKML , Anil S Keshavamurthy , "David S . Miller" , X86 ML , Andrew Cooper , Steven Rostedt Subject: Re: [RFC PATCH 1/1] x86/kprobes: Use int3 instead of debug trap for single-step Message-ID: References: <161460768474.430263.18425867006584111900.stgit@devnote2> <161460769556.430263.12936080446789384938.stgit@devnote2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 02, 2021 at 09:54:43AM +0100, Peter Zijlstra wrote: > +static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs) > +{ > + bool invert = p->ainsn.jcc.type & 1; > + bool match; > + > + if (p->ainsn.jcc.type < 0xc) { > + match = regs->flags & jcc_mask[p->ainsn.jcc.type >> 1]; > + } else { > + match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^ > + ((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT); > + if (p->ainsn.jcc.type >= 0xe) > + match = match && (regs->flags & X86_EFLAGS_ZF); > + } > + __kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert)); Also, isn't that: 'match ^ invert' ? > +}