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,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 4AC92C433E0 for ; Thu, 30 Jul 2020 20:43:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0953020838 for ; Thu, 30 Jul 2020 20:43:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HssOSb94" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726939AbgG3Unr (ORCPT ); Thu, 30 Jul 2020 16:43:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726880AbgG3Unr (ORCPT ); Thu, 30 Jul 2020 16:43:47 -0400 Received: from mail-yb1-xb42.google.com (mail-yb1-xb42.google.com [IPv6:2607:f8b0:4864:20::b42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DD80C061574 for ; Thu, 30 Jul 2020 13:43:47 -0700 (PDT) Received: by mail-yb1-xb42.google.com with SMTP id y17so15121846ybm.12 for ; Thu, 30 Jul 2020 13:43:47 -0700 (PDT) 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=Ds0prSsPKKNjln+hB/VMxkyNaySHhI1HKB2O0pgKb0M=; b=HssOSb94JJaHtehBNSfUhHm8sSxLSeSESaQgXx/T0mqDRsthMxeC7Qdba+0aeO0qyA DUy55WHrTjBcnpkAcHBYKgEFPOIQeF4BlOnG4pYU3OLQq8azB+/m5woERv6WHbETLvyZ 4UqUI75iA1NMoWTsm+X8QfOcVuLspqyaxKPm8PkrxEjhzDeNg7J21rBf+OYxJea/XPGe OsPhRT6Cdwtdu0ipcxG7cp83Deilmvhx6Cf7u+5vuF7iFgH/e3Z/1xApAzhOFCGJRcqJ xpno7SgSAmV4n/RHjZiqJq5Aa29fnHJtrgJzm66xYWbfteObK4tHF9Z/6kbc4wEwDmE5 LpXQ== 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=Ds0prSsPKKNjln+hB/VMxkyNaySHhI1HKB2O0pgKb0M=; b=kxkGP2pkWIgx5DPUT3edyT8WxjkWM0VgrvDEWHaQ4j+P/cPFq47DgZYWMTQoE1plNw u8PoyWVX0imcrVuYEpfn5CMJMcLJqfzDIR+mjYz0F6j5h5UQgkxquq4guV4hg9xqe9dP pgtpb2bb1WDjJ6htEn0p4tpTRvlAqETue78vBCL6FoA51HIvdenz/ctdUM6DX3zF0hM5 a1xkgYbBgc8VRMFBcasoN8glw/0SE9dVSQq7GMAPC38wbEiRq/dhlMpPEk0Iqp6y8bpa YgDQ1XSPedcozSVBpeeV3NkzKN3jfUxNw+YfWI/HkKrRf9FKElzGNbgqfWfgdQ4dkxou 5J4A== X-Gm-Message-State: AOAM5304V7FJBFtUaUjFeydUs5eMJbmaD66JUQEgYWoGwnf1jhPA1W4N zPKMcS9Pl5gGCqZN6bSHAXVmSjzmAsVhFdwA/z4= X-Google-Smtp-Source: ABdhPJynPgJ/Nqw+lNiPRJQ3l17TiAdcXoxm+BPkC7Xj2QtCkSfKQEjklEb8NhqaIQ0qwlXCkRw4pRODa0jMiBJ+bLk= X-Received: by 2002:a25:d84a:: with SMTP id p71mr1143582ybg.347.1596141826255; Thu, 30 Jul 2020 13:43:46 -0700 (PDT) MIME-Version: 1.0 References: <05fb9d72-d1a7-5346-b55b-4495cdf54124@web.de> <6ac86da0-16f0-eb9e-010e-277cfdd555be@web.de> In-Reply-To: <6ac86da0-16f0-eb9e-010e-277cfdd555be@web.de> From: Andrii Nakryiko Date: Thu, 30 Jul 2020 13:43:17 -0700 Message-ID: Subject: Re: [PATCH bpf] libbpf: Fix register in PT_REGS MIPS macros To: Jerry Cruntime Cc: bpf Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Jul 30, 2020 at 1:38 PM Jerry Cruntime wrote: > > Hi, > > > I've quickly looked up some doc on MIPS calling convention, doesn't > > seem like regs[8] is actually used for 5th input argument (the doc I > > found documented only the use of $4 through $7 for first 4 args). > > Should we drop PT_REGS_PARM5() for MIPS, while at it? > > My understanding is that with o32 only 4 arguments can be passed in > registers ($4-$7). But n32 and n64 extended it to pass 8 arguments in > registers ($4-$11). > > My source is "MIPS Run, Second Edition" from Dominic Sweetman table 11.2 > on page 327. It is also described here: > > https://en.wikipedia.org/wiki/Calling_convention#MIPS > Oh, right, I should have used Wikipedia instead. :) Acked-by: Andrii Nakryiko > > On 7/30/20 9:55 PM, Andrii Nakryiko wrote: > > On Thu, Jul 30, 2020 at 4:45 AM Jerry Cruntime wrote: > >> > >> The o32, n32 and n64 calling conventions require the return > >> value to be stored in $v0 which maps to $2 register, i.e., > >> the second register. > >> > >> Fixes: c1932cd ("bpf: Add MIPS support to samples/bpf.") > >> --- > >> tools/lib/bpf/bpf_tracing.h | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h > >> index 58eceb884..ae205dcf8 100644 > >> --- a/tools/lib/bpf/bpf_tracing.h > >> +++ b/tools/lib/bpf/bpf_tracing.h > >> @@ -215,7 +215,7 @@ struct pt_regs; > >> #define PT_REGS_PARM5(x) ((x)->regs[8]) > > > > I've quickly looked up some doc on MIPS calling convention, doesn't > > seem like regs[8] is actually used for 5th input argument (the doc I > > found documented only the use of $4 through $7 for first 4 args). > > Should we drop PT_REGS_PARM5() for MIPS, while at it? > > > >> #define PT_REGS_RET(x) ((x)->regs[31]) > >> #define PT_REGS_FP(x) ((x)->regs[30]) /* Works only with > >> CONFIG_FRAME_POINTER */ > >> -#define PT_REGS_RC(x) ((x)->regs[1]) > >> +#define PT_REGS_RC(x) ((x)->regs[2]) > > > > This looks good, though. > > > >> #define PT_REGS_SP(x) ((x)->regs[29]) > >> #define PT_REGS_IP(x) ((x)->cp0_epc) > >> > >> -- > >> 2.17.1