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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 EF82AC10F13 for ; Tue, 16 Apr 2019 17:45:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BA88B2075B for ; Tue, 16 Apr 2019 17:45:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="WBpjvfpM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730169AbfDPRpf (ORCPT ); Tue, 16 Apr 2019 13:45:35 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:34002 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727067AbfDPRpf (ORCPT ); Tue, 16 Apr 2019 13:45:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ut9NejS1wR0oJDJXatZJuH7z/KPsH6QzFvIh2WX6q5M=; b=WBpjvfpMqFHGvTmOkaXXijM6T 2C3+j1kZvpyhI5AVQutpLDVm+tAunjWUAEIp2kbFRIci/B9Q6qAnECt8L9kIQBMMNSL+G8o95VjxF zc79ePlyAVeLg5RmmMkJcyOKRvgQYK5ldEajwbcGzRZN/ifwP5I3VOAgzvqOL+2wPtSYJkbz57VE0 AwRKdCHpqGMW+/Uq+QuPX2BTHomy/FlQjzwR57wq+6EC35ctz8FHpe+WZyrTr6C5EO3W4kIFYYo1J soelzTtEz1ryoq2wFaB7go0Rf0m19jWKX1pjDaxtq+RLj6nSXfTTwFptOgApRKc71ut25//q2bD1i Hr01WjvIw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGS9C-0002FB-I3; Tue, 16 Apr 2019 17:45:30 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9386C29B3180A; Tue, 16 Apr 2019 19:45:28 +0200 (CEST) Date: Tue, 16 Apr 2019 19:45:28 +0200 From: Peter Zijlstra To: Kairui Song Cc: Josh Poimboeuf , Linux Kernel Mailing List , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Borislav Petkov , Dave Young Subject: Re: [RFC PATCH v2] perf/x86: make perf callchain work without CONFIG_FRAME_POINTER Message-ID: <20190416174528.GT4038@hirez.programming.kicks-ass.net> References: <20190408165942.23640-1-kasong@redhat.com> <20190415153622.GG12232@hirez.programming.kicks-ass.net> <20190415165859.ul7i2w3lai3umgik@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 17, 2019 at 01:39:19AM +0800, Kairui Song wrote: > And I also think the "fake"/"real" reg is fragile, could we abuse > another eflag (just like PERF_EFLAGS_EXACT) to indicate the regs are > partially dumped fake registers? Sure, the SDM seems to suggest bits 1,3,5,15 are 'available'. We've already used 3 and 5, and I think we can use !X86_EFLAGS_FIXED to indicate a fake regs set. Any real regs set will always have that set.