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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EAFD8C77B73 for ; Mon, 22 May 2023 08:58:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232364AbjEVI6P (ORCPT ); Mon, 22 May 2023 04:58:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230362AbjEVI5l (ORCPT ); Mon, 22 May 2023 04:57:41 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B2F2518F; Mon, 22 May 2023 01:57:33 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5796311FB; Mon, 22 May 2023 01:58:18 -0700 (PDT) Received: from [192.168.1.3] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 559A53F6C4; Mon, 22 May 2023 01:57:30 -0700 (PDT) Message-ID: <839836e8-9600-9249-dcdb-e29519335141@arm.com> Date: Mon, 22 May 2023 09:57:25 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH v1 2/5] perf parse-regs: Introduce functions arch__reg_{ip|sp}() Content-Language: en-US To: Leo Yan References: <20230520025537.1811986-1-leo.yan@linaro.org> <20230520025537.1811986-3-leo.yan@linaro.org> Cc: Arnaldo Carvalho de Melo , John Garry , Will Deacon , Mike Leach , Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Guo Ren , Paul Walmsley , Palmer Dabbelt , Albert Ou , Eric Lin , Kan Liang , Qi Liu , Sandipan Das , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-csky@vger.kernel.org, linux-riscv@lists.infradead.org From: James Clark In-Reply-To: <20230520025537.1811986-3-leo.yan@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On 20/05/2023 03:55, Leo Yan wrote: > Ideally, we want util/perf_regs.c to be general enough and doesn't bind > with specific architecture. > > But since util/perf_regs.c uses the macros PERF_REG_IP and PERF_REG_SP > which are defined by architecture, thus util/perf_regs.c is dependent on > architecture header (see util/perf_regs.h includes "", here > perf_regs.h is architecture specific header). > > As a step to generalize util/perf_regs.c, this commit introduces weak > functions arch__reg_ip() and arch__reg_sp() and every architecture can > define their own functions; thus, util/perf_regs.c doesn't need to use > PERF_REG_IP and PERF_REG_SP anymore. > > This is a preparation to get rid of architecture specific header from > util/perf_regs.h. > > Signed-off-by: Leo Yan > --- [...] > > -#define DWARF_MINIMAL_REGS ((1ULL << PERF_REG_IP) | (1ULL << PERF_REG_SP)) > +#define DWARF_MINIMAL_REGS ((1ULL << arch__reg_ip()) | (1ULL << arch__reg_sp())) > > const char *perf_reg_name(int id, const char *arch); > int perf_reg_value(u64 *valp, struct regs_dump *regs, int id); > diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c > index bdccfc511b7e..f308f2ea512b 100644 > --- a/tools/perf/util/unwind-libdw.c > +++ b/tools/perf/util/unwind-libdw.c > @@ -252,7 +252,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, > if (!ui->dwfl) > goto out; > > - err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); > + err = perf_reg_value(&ip, &data->user_regs, arch__reg_ip()); Shouldn't it be more like this, because the weak symbols are a compile time thing and it's supposed to support cross arch unwinding at runtime (assuming something containing the arch from the file is passed down, like we did with perf_reg_name()): char *arch = perf_env__arch(evsel__env(evsel)); err = perf_reg_value(&ip, &data->user_regs, arch__reg_ip(arch)); Now I'm wondering how cross unwinding ever worked because I see libunwind also has something hard coded too: #define LIBUNWIND__ARCH_REG_SP PERF_REG_SP