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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 E7142C606D1 for ; Mon, 8 Jul 2019 21:20:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B463B2086D for ; Mon, 8 Jul 2019 21:20:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=fomichev-me.20150623.gappssmtp.com header.i=@fomichev-me.20150623.gappssmtp.com header.b="j4p9XZTM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732517AbfGHVUO (ORCPT ); Mon, 8 Jul 2019 17:20:14 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:39195 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732476AbfGHVUO (ORCPT ); Mon, 8 Jul 2019 17:20:14 -0400 Received: by mail-pf1-f195.google.com with SMTP id j2so8202082pfe.6 for ; Mon, 08 Jul 2019 14:20:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fomichev-me.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=x0Zfx6J5t7C/VzP4ZN5cW6JbMAzBqC9yvvudAewYVms=; b=j4p9XZTMkEzSKYqVZPxUg2rMJvfHYOORuJ4dPSpE9FIqvH+ZIkEVxGyj9/SqiCBbu0 8kJlJc0qJFD3ybchVBgAZLiPMDtNVbDRbcEcOFWd5G/slaXjXwvw9zYTcpR3UsujvDkT p5VIAG3c6CCPZmkQy74ctskMMjiUbNIwXvMxMW13mhheuAdR0CtDnTADu9pFV6txSzPo JzvRnwfYX45rQVNUa+BhSLAR8nwvBAmGxCj2v0v2+4YHL1gAKa08p638RCBxYeKAReQ8 vgdT1SFYwqnqsiXc7hb8zOzR1RgS+gEGDVL9w84tPoaJZd+GU9blYKBaxL4VOSOaqnEy VFXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=x0Zfx6J5t7C/VzP4ZN5cW6JbMAzBqC9yvvudAewYVms=; b=nORuPugQPFUVyWmjGJVDfd/PQClj+5/PDo86cxOYAWqjPfXbEBWoMBX+YYNB+1arno AYk85lp1yvKVP0i+iO1RlGb/SBf7vGxc4P5G5akAyyntL27VG91oXmYU2ajam7tECBLz f+LjM9cc3aEFLqFV17djZbN2urNdFOODecKnp0Bp4p3HHHDVzJ1til6KfduHrV8zyIJA R36A0g9oXLT+Zdh+kgGdwl32UgdXLEWyrQBwPXlnG/SsHmoV2NICzWfdvG6uQKKLjGvJ EAVKsBOrQ4Ag6B9tGQV8Kh5+iGJWMD77K6VEd1FB7v3WQtFc44/UxZBnkXP7DBSjNQZn ocXA== X-Gm-Message-State: APjAAAWZqrXn4s1V+GHQNze0bm1VWD/aQUe/YVAXmi0TURu8fZckueED 0tZD8hpg9iRU1/PgcbJDctK8Qg== X-Google-Smtp-Source: APXvYqwd0ctnUcrtexli5I1HDrCKU72TCRH08/KkYtJXxraMc73AiwFsB4/pGyQqzoslmKdYgLLe6A== X-Received: by 2002:a17:90b:d8a:: with SMTP id bg10mr28390728pjb.92.1562620813471; Mon, 08 Jul 2019 14:20:13 -0700 (PDT) Received: from localhost ([2601:646:8f00:18d9:d0fa:7a4b:764f:de48]) by smtp.gmail.com with ESMTPSA id e11sm23767917pfm.35.2019.07.08.14.20.12 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 08 Jul 2019 14:20:12 -0700 (PDT) Date: Mon, 8 Jul 2019 14:20:12 -0700 From: Stanislav Fomichev To: Ilya Leoshkevich Cc: Y Song , Stanislav Fomichev , netdev , bpf , David Miller , Alexei Starovoitov , Daniel Borkmann Subject: Re: [PATCH bpf-next] selftests/bpf: make verifier loop tests arch independent Message-ID: <20190708212012.GA9509@mini-arch> References: <20190703205100.142904-1-sdf@google.com> <20190708161338.GC29524@mini-arch> <99593C98-5DEC-4B18-AE6D-271DD8A8A7F6@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <99593C98-5DEC-4B18-AE6D-271DD8A8A7F6@linux.ibm.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 07/08, Ilya Leoshkevich wrote: > > > > Am 08.07.2019 um 18:13 schrieb Stanislav Fomichev : > > > > On 07/03, Y Song wrote: > >> On Wed, Jul 3, 2019 at 1:51 PM Stanislav Fomichev wrote: > >>> > >>> Take the first x bytes of pt_regs for scalability tests, there is > >>> no real reason we need x86 specific rax. > >>> > >>> Signed-off-by: Stanislav Fomichev > >>> --- > >>> tools/testing/selftests/bpf/progs/loop1.c | 3 ++- > >>> tools/testing/selftests/bpf/progs/loop2.c | 3 ++- > >>> tools/testing/selftests/bpf/progs/loop3.c | 3 ++- > >>> 3 files changed, 6 insertions(+), 3 deletions(-) > >>> > >>> diff --git a/tools/testing/selftests/bpf/progs/loop1.c b/tools/testing/selftests/bpf/progs/loop1.c > >>> index dea395af9ea9..d530c61d2517 100644 > >>> --- a/tools/testing/selftests/bpf/progs/loop1.c > >>> +++ b/tools/testing/selftests/bpf/progs/loop1.c > >>> @@ -14,11 +14,12 @@ SEC("raw_tracepoint/kfree_skb") > >>> int nested_loops(volatile struct pt_regs* ctx) > >>> { > >>> int i, j, sum = 0, m; > >>> + volatile int *any_reg = (volatile int *)ctx; > >>> > >>> for (j = 0; j < 300; j++) > >>> for (i = 0; i < j; i++) { > >>> if (j & 1) > >>> - m = ctx->rax; > >>> + m = *any_reg; > >> > >> I agree. ctx->rax here is only to generate some operations, which > >> cannot be optimized away by the compiler. dereferencing a volatile > >> pointee may just serve that purpose. > >> > >> Comparing the byte code generated with ctx->rax and *any_reg, they are > >> slightly different. Using *any_reg is slighly worse, but this should > >> be still okay for the test. > >> > >>> else > >>> m = j; > >>> sum += i * m; > >>> diff --git a/tools/testing/selftests/bpf/progs/loop2.c b/tools/testing/selftests/bpf/progs/loop2.c > >>> index 0637bd8e8bcf..91bb89d901e3 100644 > >>> --- a/tools/testing/selftests/bpf/progs/loop2.c > >>> +++ b/tools/testing/selftests/bpf/progs/loop2.c > >>> @@ -14,9 +14,10 @@ SEC("raw_tracepoint/consume_skb") > >>> int while_true(volatile struct pt_regs* ctx) > >>> { > >>> int i = 0; > >>> + volatile int *any_reg = (volatile int *)ctx; > >>> > >>> while (true) { > >>> - if (ctx->rax & 1) > >>> + if (*any_reg & 1) > >>> i += 3; > >>> else > >>> i += 7; > >>> diff --git a/tools/testing/selftests/bpf/progs/loop3.c b/tools/testing/selftests/bpf/progs/loop3.c > >>> index 30a0f6cba080..3a7f12d7186c 100644 > >>> --- a/tools/testing/selftests/bpf/progs/loop3.c > >>> +++ b/tools/testing/selftests/bpf/progs/loop3.c > >>> @@ -14,9 +14,10 @@ SEC("raw_tracepoint/consume_skb") > >>> int while_true(volatile struct pt_regs* ctx) > >>> { > >>> __u64 i = 0, sum = 0; > >>> + volatile __u64 *any_reg = (volatile __u64 *)ctx; > >>> do { > >>> i++; > >>> - sum += ctx->rax; > >>> + sum += *any_reg; > >>> } while (i < 0x100000000ULL); > >>> return sum; > >>> } > >>> -- > >>> 2.22.0.410.gd8fdbe21b5-goog > >> > >> Ilya Leoshkevich (iii@linux.ibm.com, cc'ed) has another patch set > >> trying to solve this problem by introducing s360 arch register access > >> macros. I guess for now that patch set is not needed any more? > > Oh, I missed them. Do they fix the tests for other (non-s360) arches as > > well? I was trying to fix the issue by not depending on any arch > > specific stuff because the test really doesn't care :-) > > They are supposed to work for everything that defines PT_REGS_RC in > bpf_helpers.h, but I have to admit I tested only x86_64 and s390. > > The main source of problems with my approach were mismatching definitions > of struct pt_regs for userspace and kernel, and because of that there was > some tweaking required for both arches. I will double check how it looks > for others (arm, mips, ppc, sparc) tomorrow. Thanks, I've tested your patches and they fix my issue as well. So you can have my Tested-by if we'd go with your approach. One thing I don't understand is: why do you add 'ifdef __KERNEL__' to the bpf_helpers.h for x86 case? Who is using bpf_helpers.h with __KERNEL__ defined? Is it perf? > Best regards, > Ilya