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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 CCB21C433E9 for ; Sun, 7 Mar 2021 03:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A420B65076 for ; Sun, 7 Mar 2021 03:14:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230094AbhCGDOL (ORCPT ); Sat, 6 Mar 2021 22:14:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230045AbhCGDNm (ORCPT ); Sat, 6 Mar 2021 22:13:42 -0500 Received: from mail-yb1-xb29.google.com (mail-yb1-xb29.google.com [IPv6:2607:f8b0:4864:20::b29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEB68C06174A; Sat, 6 Mar 2021 19:13:29 -0800 (PST) Received: by mail-yb1-xb29.google.com with SMTP id u75so6409116ybi.10; Sat, 06 Mar 2021 19:13:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ukm4FF97j3LFYLEbomttgTdVBJw6RIlzQsc6gDhVDes=; b=GFO2qxZtYot5ebaiZzSXNQGsJhiHt5OHmfZ54lTbZPGGRpJ6csNIUpXeeg2IrKFUkt KNeBemeyvLUfuLcpTjUMdpNL8kyVaaO/ipuyV54MJkonIGVTqzXFScbKYn8H1LdjRGJ8 HftB5PYP/QapXTKV8E2I4gGWpXibF/rPp+/gfZUOl1H+XbPJ7mc3UXnbVIuFtA3ucuID 7dkukSLBW5vZ3W17nZi/2rX3WaPjjqmTm8K1IrUZBUPww8VrnsNyk7rwlMqSdC68K+uI Yo/uY1tAsfzczj09D2g8E1KYmA2SxMiZksL69YBtki/rp3lQRVqw1MBG9XAcM+PqXW8V sreg== 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=ukm4FF97j3LFYLEbomttgTdVBJw6RIlzQsc6gDhVDes=; b=VRT0zTdAMoYl+RIsYjTuTqoM2IUxAaHGQ+1YfL+Hc7KcV+Ud89lVJr+6PdUX2lRzFO STHcGHS+AZ3wk070TEKVRvxd1OSoKlkLuXd806nv7V4NiYbtyj08w9xV8zbMwasDSsQw NzqZae63xKuHI+5XMFO++o8SgWWb1WxLSayK2jZnGyBGEaaC83/BkYWy7G5FsjkTt30L 7FwDuB1qkEBRSPHlY/5IL4n4w+b1zwa/867qwOPg6h0jaXjKpO+9EzYCAzzL6vjA/jEg VJZ+gul/ZgeAhsX+YL+LGtL9XdVp6kBisehn5BWT0SMTn2OrZ/ubdDJYgHVvAim4ARkt MJrA== X-Gm-Message-State: AOAM531r+qKoSR12TjLl0/ywpZlbzEFAsDnxpzaoV4GOym+m3LnCZW7Z t9rmYE9HQYbC3w7dvwuZXIT/WyIJy/kirLZSbfQ= X-Google-Smtp-Source: ABdhPJyDqnIYvgu+uRfrS2rOAw3QEZQOF/3/yWxKMeyif1YHUO/irIwep364lu3o9SQ3vVenFt0tvlxmBj43YWbKpps= X-Received: by 2002:a25:bd12:: with SMTP id f18mr24038195ybk.403.1615086808614; Sat, 06 Mar 2021 19:13:28 -0800 (PST) MIME-Version: 1.0 References: <20210305134050.139840-1-jolsa@kernel.org> In-Reply-To: <20210305134050.139840-1-jolsa@kernel.org> From: Andrii Nakryiko Date: Sat, 6 Mar 2021 19:13:17 -0800 Message-ID: Subject: Re: [PATCHv2 bpf-next] selftests/bpf: Fix test_attach_probe for powerpc uprobes To: Jiri Olsa Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Michael Ellerman , "Naveen N . Rao" , Networking , bpf , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , Yauheni Kaliuta Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Mar 5, 2021 at 5:42 AM Jiri Olsa wrote: > > When testing uprobes we the test gets GEP (Global Entry Point) > address from kallsyms, but then the function is called locally > so the uprobe is not triggered. > > Fixing this by adjusting the address to LEP (Local Entry Point) > for powerpc arch plus instruction check stolen from ppc_function_entry > function pointed out and explained by Michael and Naveen. > > Cc: Michael Ellerman > Cc: Naveen N. Rao > Signed-off-by: Jiri Olsa > --- > .../selftests/bpf/prog_tests/attach_probe.c | 40 ++++++++++++++++++- > 1 file changed, 39 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c > index a0ee87c8e1ea..9dc4e3dfbcf3 100644 > --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c > +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c > @@ -2,6 +2,44 @@ > #include > #include "test_attach_probe.skel.h" > > +#if defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2 > + > +#define OP_RT_RA_MASK 0xffff0000UL > +#define LIS_R2 0x3c400000UL > +#define ADDIS_R2_R12 0x3c4c0000UL > +#define ADDI_R2_R2 0x38420000UL > + > +static ssize_t get_offset(ssize_t addr, ssize_t base) > +{ > + u32 *insn = (u32 *) addr; > + > + /* > + * A PPC64 ABIv2 function may have a local and a global entry > + * point. We need to use the local entry point when patching > + * functions, so identify and step over the global entry point > + * sequence. > + * > + * The global entry point sequence is always of the form: > + * > + * addis r2,r12,XXXX > + * addi r2,r2,XXXX > + * > + * A linker optimisation may convert the addis to lis: > + * > + * lis r2,XXXX > + * addi r2,r2,XXXX > + */ > + if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) || > + ((*insn & OP_RT_RA_MASK) == LIS_R2)) && > + ((*(insn + 1) & OP_RT_RA_MASK) == ADDI_R2_R2)) > + return (ssize_t)(insn + 2) - base; > + else > + return addr - base; > +} > +#else > +#define get_offset(addr, base) (addr - base) I turned this into a static function, not sure why you preferred #define here. Applied to bpf-next. > +#endif > + > ssize_t get_base_addr() { > size_t start, offset; > char buf[256]; > @@ -36,7 +74,7 @@ void test_attach_probe(void) > if (CHECK(base_addr < 0, "get_base_addr", > "failed to find base addr: %zd", base_addr)) > return; > - uprobe_offset = (size_t)&get_base_addr - base_addr; > + uprobe_offset = get_offset((size_t)&get_base_addr, base_addr); > > skel = test_attach_probe__open_and_load(); > if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) > -- > 2.27.0 >