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=-14.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 BE604C433E0 for ; Wed, 30 Dec 2020 09:01:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7826420784 for ; Wed, 30 Dec 2020 09:01:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726290AbgL3JBg (ORCPT ); Wed, 30 Dec 2020 04:01:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:53664 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725814AbgL3JBg (ORCPT ); Wed, 30 Dec 2020 04:01:36 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5FB1920784; Wed, 30 Dec 2020 09:00:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609318855; bh=VGbxPk1NisiSqYxd4Nqxce4ZFoGBlCOFkyUjPMIVssA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nQBQP3ctDgLy6CjpvBdtIY0Kh9GgbLeT50ysY1W49r0Xb/zCIlUNJ0wTo/vAf8TPa JfPHizDur9486FXFWv9nrfmDTwr2qWB07V0+70ScowvXeimWBV6UCiVqINve+9x1Fo rx2O+Ew54kL697mCGKGgbjBEQOuFkoP7mFdw+ty2vcK3CVrp87kYbDjWRTAiWzaqdZ FL6IxmB2oMQ64KbSQkFDIoyFOE0aVp+fJT3se29XfvfWWD1w5nIkhw5wDNvgM05vqO 1kvugbn/094NF2O24i3gPftqvT4/zxjMrex6ijS7cln56STbr9mHFkjSF1fLGU01Ps Nfp2Bob37kq9w== Date: Wed, 30 Dec 2020 18:00:52 +0900 From: Masami Hiramatsu To: Borislav Petkov Cc: Andy Lutomirski , X86 ML , LKML Subject: Re: [PATCH v1 03/19] x86/insn: Add an insn_decode() API Message-Id: <20201230180052.7e1931b4e1b17079023b65b7@kernel.org> In-Reply-To: <20201229200654.GF29947@zn.tnic> References: <20201223174233.28638-1-bp@alien8.de> <20201223174233.28638-4-bp@alien8.de> <20201228101510.49082d470ed328d81486ef04@kernel.org> <20201229200654.GF29947@zn.tnic> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 29 Dec 2020 21:06:54 +0100 Borislav Petkov wrote: > On Mon, Dec 28, 2020 at 10:15:10AM +0900, Masami Hiramatsu wrote: > > BTW, insn_decode() can return -EINVAL if !insn_complete(), is that OK? > > It does with this change. Or are you asking whether it returning -EINVAL > in that case is ok? > > I don't see why not - this way callers can differentiate where it failed > - at fetching bytes with -ENODATA or it wasn't decoded completely - > -EINVAL. Ah, I got it. > > > I think tools clone code must not use INSN_MODE_KERN because the tools may > > not use kernel Kconfig. > > > > Hmm, this may be better to make a different patch to introduce a NOSYNC tag > > for sync checker in the tools. Something like; > > I'd actually prefer this: > > diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h > index f8772b371452..545320c67855 100644 > --- a/tools/arch/x86/include/asm/insn.h > +++ b/tools/arch/x86/include/asm/insn.h > @@ -98,8 +98,6 @@ extern int insn_get_length(struct insn *insn); > enum insn_mode { > INSN_MODE_32, > INSN_MODE_64, > - /* Mode is determined by the current kernel build. */ > - INSN_MODE_KERN, > INSN_NUM_MODES, > }; Agreed. This is much simpler. Maybe I need to replace it with dummy lines but it is possible. > > > so that when a tool does use INSN_MODE_KERN, it would fail building: > > In file included from util/intel-pt-decoder/intel-pt-insn-decoder.c:15: > util/intel-pt-decoder/../../../arch/x86/lib/insn.c: In function ‘insn_decode’: > util/intel-pt-decoder/../../../arch/x86/lib/insn.c:751:11: error: ‘INSN_MODE_KERN’ undeclared (first use in this function); did you mean ‘INSN_MODE_64’? > 751 | if (m == INSN_MODE_KERN) > | ^~~~~~~~~~~~~~ > | INSN_MODE_64 This part is OK. I can replace it with dummy lines. > util/intel-pt-decoder/../../../arch/x86/lib/insn.c:751:11: note: each undeclared identifier is reported only once for each function it appears in > LD arch/perf-in.o > util/intel-pt-decoder/intel-pt-insn-decoder.c: In function ‘intel_pt_get_insn’: > util/intel-pt-decoder/intel-pt-insn-decoder.c:163:37: error: ‘INSN_MODE_KERN’ undeclared (first use in this function); did you mean ‘INSN_MODE_64’? > 163 | ret = insn_decode(&insn, buf, len, INSN_MODE_KERN); > | ^~~~~~~~~~~~~~ > | INSN_MODE_64 But in [17/19], your patch seems not using INSN_MODE_KERN there. --- a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c @@ -158,11 +158,13 @@ int intel_pt_get_insn(const unsigned char *buf, size_t len, int x86_64, struct intel_pt_insn *intel_pt_insn) { struct insn insn; + int ret; - insn_init(&insn, buf, len, x86_64); - insn_get_length(&insn); - if (!insn_complete(&insn) || insn.length > len) + ret = insn_decode(&insn, buf, len, + x86_64 ? INSN_MODE_64 : INSN_MODE_32); + if (ret < 0 || insn.length > len) return -1; + intel_pt_insn_decoder(&insn, intel_pt_insn); if (insn.length < INTEL_PT_INSN_BUF_SZ) memcpy(intel_pt_insn->buf, buf, insn.length); Thank you, -- Masami Hiramatsu