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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DE3FBC433E0 for ; Wed, 29 Jul 2020 21:36:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B194620809 for ; Wed, 29 Jul 2020 21:36:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596058597; bh=bygAj4IRMJ/H+qqV44HiSS+jQ8yHN707Z52/EZCUesY=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=pIyWLfvyPu7yzz4l8czY5boCNDNTYt/QtBZBDBEYBhaI1CojOafqYGrKBqJm3Abj8 +5VkvD6ilrK2YQf2RttVZd5IzWC3yR5MrdlhdmTn1WpS+asPwEaj/4h4ChzANdnSTJ QVJY9DOHimwqVEv4rWWOkV8r+JoLwlCXAtFbTbAM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727794AbgG2Vgh (ORCPT ); Wed, 29 Jul 2020 17:36:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:41788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726365AbgG2Vgh (ORCPT ); Wed, 29 Jul 2020 17:36:37 -0400 Received: from mail-lj1-f178.google.com (mail-lj1-f178.google.com [209.85.208.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 583672082E; Wed, 29 Jul 2020 21:36:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596058596; bh=bygAj4IRMJ/H+qqV44HiSS+jQ8yHN707Z52/EZCUesY=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=lYiSYccCU52pS5ClVwRb1pnRB0Aq34GWggclxt4rcXlOKGKmktoKGdE2nuP7ImHfy tLkcGlGzsboPc17Yh+kigSP79/d7CUz1ZiD381OnMyWcw1JNMOD2VAQGieUkeqqQEp 9MzQ2IJPHo0jpjc5rMKhhiQgcWFAC8dR/writ8hU= Received: by mail-lj1-f178.google.com with SMTP id 185so16431422ljj.7; Wed, 29 Jul 2020 14:36:36 -0700 (PDT) X-Gm-Message-State: AOAM533VHvopikzuJSs8AU8FqbYp25mZgew1/2KjfBtuf8bvm7nqI26v S9oZXLxgJA/6RCwejJcF3r6Lhn7ycrBiWcee4FM= X-Google-Smtp-Source: ABdhPJySNOAl/9Gvukw4uH/X1mWvKTx3s9TUheBzPpW3tN1gHv1Dg6Zz/62bukIr6uosZ3p0z009C6DhIZDohE2S4OY= X-Received: by 2002:a2e:81c2:: with SMTP id s2mr220235ljg.10.1596058594692; Wed, 29 Jul 2020 14:36:34 -0700 (PDT) MIME-Version: 1.0 References: <159603940602.4454.2991262810036844039.stgit@john-Precision-5820-Tower> <159603983037.4454.12599156913109163942.stgit@john-Precision-5820-Tower> In-Reply-To: <159603983037.4454.12599156913109163942.stgit@john-Precision-5820-Tower> From: Song Liu Date: Wed, 29 Jul 2020 14:36:23 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [bpf PATCH v2 4/5] bpf, selftests: Add tests for sock_ops load with r9, r8.r7 registers To: John Fastabend Cc: Martin KaFai Lau , Daniel Borkmann , Alexei Starovoitov , Networking , bpf Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jul 29, 2020 at 9:24 AM John Fastabend wrote: > > Loads in sock_ops case when using high registers requires extra logic to > ensure the correct temporary value is used. We need to ensure the temp > register does not use either the src_reg or dst_reg. Lets add an asm > test to force the logic is triggered. > > The xlated code is here, > > 30: (7b) *(u64 *)(r9 +32) = r7 > 31: (61) r7 = *(u32 *)(r9 +28) > 32: (15) if r7 == 0x0 goto pc+2 > 33: (79) r7 = *(u64 *)(r9 +0) > 34: (63) *(u32 *)(r7 +916) = r8 > 35: (79) r7 = *(u64 *)(r9 +32) > > Notice r9 and r8 are not used for temp registers and r7 is chosen. > > Signed-off-by: John Fastabend Acked-by: Song Liu [...]