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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 3E1D9C282DA for ; Wed, 17 Apr 2019 14:42:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 061DF20663 for ; Wed, 17 Apr 2019 14:42:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732484AbfDQOmE (ORCPT ); Wed, 17 Apr 2019 10:42:04 -0400 Received: from mail-io1-f66.google.com ([209.85.166.66]:45148 "EHLO mail-io1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729395AbfDQOmE (ORCPT ); Wed, 17 Apr 2019 10:42:04 -0400 Received: by mail-io1-f66.google.com with SMTP id s7so1524771iom.12 for ; Wed, 17 Apr 2019 07:42:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mDYvFmdHCEUniLd5QA51M6EpL/xNYNtgFWJ3bzHoUHg=; b=IqsWM4NWS3E0mRO27mSE8n074F6n54yf8a+eLehSX/2KJBi0natoNccE+UgkjF/HU/ CdUi7K6K44gD7PMm2NtqBKDdSZhPwYSxVIfHr8JBbCJ2Gp53ZE4r+wuch5ty2NtQXwfW 0Kk1UXQs3yPmwCvkj3vJ3DK/f2A139jqRsGCJ7q+TfRBOxeGFHq5nV2MoleE/HSFRiDc IBwIpfWt9LMdQaQ8mEpUCWszQ/1i7Bt+WRAfQcXRwDCvpw3GrFAqcHHF5nlXU8VzH5Gv JzczURnuySDLRySthI9C+QFLXCmRvuPlS9ANpIgltD88QEGTjzDiUCG12uWXA0ntdnxP Q9QQ== X-Gm-Message-State: APjAAAW0xUZHI8jHZ/2jTANBFahZbSOTcUqT2Is46gttVFgfxHtrnEN8 SWQGY11atrNurqwvZOQJ9stDJp+zGCDbK5xIVuua6w== X-Google-Smtp-Source: APXvYqzl+CFpGFse89HMRWaGDEuy2Q/EHR+Jt7G5TYpuMb03koyX5q0FwAtabQDeda9ubBwhT2jdwk8gh6kz/9oeiCg= X-Received: by 2002:a5d:8757:: with SMTP id k23mr7328589iol.68.1555512123473; Wed, 17 Apr 2019 07:42:03 -0700 (PDT) MIME-Version: 1.0 References: <20190408165942.23640-1-kasong@redhat.com> <20190415153622.GG12232@hirez.programming.kicks-ass.net> <20190415165859.ul7i2w3lai3umgik@treble> <20190416174528.GT4038@hirez.programming.kicks-ass.net> In-Reply-To: <20190416174528.GT4038@hirez.programming.kicks-ass.net> From: Kairui Song Date: Wed, 17 Apr 2019 22:41:52 +0800 Message-ID: Subject: Re: [RFC PATCH v2] perf/x86: make perf callchain work without CONFIG_FRAME_POINTER To: Peter Zijlstra 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 Content-Type: text/plain; charset="UTF-8" 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 1:45 AM Peter Zijlstra wrote: > > 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. Thanks! This is a good idea. Will update accordingly in V3 later. -- Best Regards, Kairui Song