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 DEED9C74A5B for ; Thu, 30 Mar 2023 05:40:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229692AbjC3FkG (ORCPT ); Thu, 30 Mar 2023 01:40:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229841AbjC3FkE (ORCPT ); Thu, 30 Mar 2023 01:40:04 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13511129; Wed, 29 Mar 2023 22:40:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680154803; x=1711690803; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=BUu0pGc3jLjsMJmRH0RA8X7WqPpdGksVXTppQ0KLIrY=; b=Ug8OO5L7ekah4Lh27duYqD+gqfSbCBhU2QmCB2S6I4G7xmX8aO0o5A15 POUuX7mE4fbHFpwYjtx4BAE9ACzCr7hAeURkObqL6pp8W69l1Kwohqi5d eTfq8ZiJWMAWGhCNdJ38UBfAooqS4p7Tv4fGFn8OwEtEtbn7kWSolbpjk T7JvnqRoyFtxhUNmN60UM1G7cEJ/YYYDBj9RCgrgrXwjnwapPZyccMVVm ZkbzAKbA3fD5IWLKCcQOjmKzo9fJFujhzeqq6EXbz1F/5LcahJbFdwf8x vQEmJAZ1bTgGP/pJuzPFKeYunLl/3jQARyAX7/lUE894tNvYrNJL9cPSD g==; X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="368851933" X-IronPort-AV: E=Sophos;i="5.98,303,1673942400"; d="scan'208";a="368851933" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 22:40:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="678060062" X-IronPort-AV: E=Sophos;i="5.98,303,1673942400"; d="scan'208";a="678060062" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.249.32.122]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 22:39:53 -0700 Message-ID: Date: Thu, 30 Mar 2023 08:39:48 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.9.1 Subject: Re: [PATCH v1 0/6] Simplify linking against tools/perf code Content-Language: en-US To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , John Garry , Will Deacon , James Clark , Mike Leach , Leo Yan , Mathieu Poirier , Suzuki K Poulose , Kan Liang , Raul Silvera , Athira Rajeev , Ravi Bangoria , Florian Fischer , Rob Herring , Xing Zhengjun , Sean Christopherson , Chengdong Li , Denis Nikitin , =?UTF-8?Q?Martin_Li=c5=a1ka?= , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org References: <20230328014058.870413-1-irogers@google.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/03/23 20:42, Ian Rogers wrote: > On Tue, Mar 28, 2023 at 10:12 AM Adrian Hunter wrote: >> >> On 28/03/23 19:14, Ian Rogers wrote: >>> On Tue, Mar 28, 2023 at 6:24 AM Adrian Hunter wrote: >>>> >>>> On 28/03/23 04:40, Ian Rogers wrote: >>>>> When fuzzing something like parse-events, having the main function in >>>>> perf.c alongside global variables like input_name means that >>>>> input_name must be redeclared with the fuzzer function's >>>>> main. However, as the fuzzer is using the tools/perf code as a library >>>>> this causes backward linking reference that the linker may warn >>>>> about. Reorganize perf.c and perf.h to avoid potential backward >>>>> references, or so that the declaration/definition locations are more >>>>> consistent. >>>>> >>>> >>>> Seems like it could be a pain to maintain. >>>> >>>> Did you consider just adding: >>>> >>>> diff --git a/tools/perf/perf.c b/tools/perf/perf.c >>>> index 82bbe0ca858b..a75dd47d68ee 100644 >>>> --- a/tools/perf/perf.c >>>> +++ b/tools/perf/perf.c >>>> @@ -456,6 +456,7 @@ static int libperf_print(enum libperf_print_level level, >>>> return veprintf(level, verbose, fmt, ap); >>>> } >>>> >>>> +#ifndef CUSTOM_MAIN >>>> int main(int argc, const char **argv) >>>> { >>>> int err; >>>> @@ -576,3 +577,4 @@ int main(int argc, const char **argv) >>>> out: >>>> return 1; >>>> } >>>> +#endif >>>> >>> >>> It's possible. Would need to make the static functions not warn about >>> being declared and not used. I still think that just aligning >>> definitions and declarations yields the most expected code and will >>> lead to fewer problems in the long run. >> >> Making perf source dependent on an unknown derivative makes >> things more complicated. >> >> If you are not going to contribute it to perf, then a >> suggestion is along the lines of the following: > > There's not an issue with contribution, most of the fuzzers are very > simple. For example, here is the coresight fuzzer we run: > > ``` > #include > > extern "C" { > #include "tools/perf/util/cs-etm-decoder/cs-etm-decoder.h" > } > > static void null_packet_dump(const char *) {} > > extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { > FuzzedDataProvider fdp(data, size); > int num_cpu = fdp.ConsumeIntegralInRange(1, 1024); > struct cs_etm_decoder_params d_params; > std::unique_ptr > t_params(new cs_etm_trace_params[num_cpu]); > > for(int i=0; i < num_cpu; ++i) { > t_params[i].protocol = > fdp.ConsumeIntegralInRange(static_cast(CS_ETM_PROTO_ETMV3) > , > > static_cast(CS_ETM_PROTO_PTM)); > fdp.ConsumeData(&t_params[i].etmv4, sizeof(struct cs_etmv4_trace_params)); > } > > d_params.packet_printer = null_packet_dump; > d_params.operation = CS_ETM_OPERATION_DECODE; > d_params.data = NULL; > d_params.formatted = true; > d_params.fsyncs = false; > d_params.hsyncs = false; > d_params.frame_aligned = true; > > std::unique_ptr > decoder(cs_etm_decoder__new(num_cpu, &d_params, t_params.get()), > cs_etm_decoder__free); > > if (decoder == nullptr) > return 0; > > do { > size_t consumed; > uint8_t buf[1024]; > size_t len = fdp.ConsumeData(buf, sizeof(buf)); > > int ret = cs_etm_decoder__process_data_block( > decoder.get(), 0, buf, len, &consumed); > if (ret) > return 0; > > } while (fdp.remaining_bytes() > 0); > > return 0; > } > ``` > Most of the code is boiler plate around a single function call. The > issues are build support, where to put the fuzzer generated test > corpus, the code is C++, etc. > >> diff --git a/tools/perf/perf.c b/tools/perf/perf.c >> index 82bbe0ca858b..6a7fe1534664 100644 >> --- a/tools/perf/perf.c >> +++ b/tools/perf/perf.c >> @@ -456,7 +456,18 @@ static int libperf_print(enum libperf_print_level level, >> return veprintf(level, verbose, fmt, ap); >> } >> >> $ git diff >> +#ifdef CUSTOM_MAIN >> +int main(void) >> +{ >> + printf("This is not perf\n"); >> + return 0; >> +} >> + >> +int perf_main(int argc, const char **argv); >> +int perf_main(int argc, const char **argv) >> +#else >> int main(int argc, const char **argv) >> +#endif >> { >> int err; >> const char *cmd; >> $ make EXTRA_CFLAGS="-DCUSTOM_MAIN" NO_BPF_SKEL=1 -C tools/perf >/dev/null >> Warning: Kernel ABI header at 'tools/include/uapi/linux/in.h' differs from latest version at 'include/uapi/linux/in.h' >> Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h' >> Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/perf_regs.h' differs from latest version at 'arch/arm64/include/uapi/asm/perf_regs.h' >> Warning: Kernel ABI header at 'tools/include/linux/coresight-pmu.h' differs from latest version at 'include/linux/coresight-pmu.h' >> Makefile.config:587: No sys/sdt.h found, no SDT events are defined, please install systemtap-sdt-devel or systemtap-sdt-dev >> Makefile.config:805: Missing perl devel files. Disabling perl scripting support, please install perl-ExtUtils-Embed/libperl-dev >> Makefile.config:1046: No libbabeltrace found, disables 'perf data' CTF format support, please install libbabeltrace-dev[el]/libbabeltrace-ctf-dev >> Makefile.config:1075: No alternatives command found, you need to set JDIR= to point to the root of your Java directory >> Makefile.config:1137: libpfm4 not found, disables libpfm4 support. Please install libpfm4-dev >> $ tools/perf/perf version >> This is not perf >> > > Sure, I'm aware of how the #ifdef would function. What I'm saying is > that even with a CUSTOM_MAIN ifdef, which wouldn't be necessary with > my patches as you can drop the object file, the refactoring in the > patches still makes sense. I am just going off what your commit messages say > > perf ui: Move window resize signal functions > > It isn't clear why these UI functions should be in perf.c given window > resizing is a UI issue. > > perf usage: Move usage strings > > The usage strings were in builtin.h and not perf.h, so the > declaration/definition didn't align. util.h declares usage(), although > the definition is in usage.c, the variables are moved to match this. > > perf header: Move perf_version_string declaration > > perf_version_string is defined in header.c and so declaring it in > header.h rather than perf.h is consistent. > > perf version: Use regular verbose flag > > Just remove an unnecessary global by repurposing the existing global > for the job. > > perf util: Move input_name to util > > There's no reference to input_name in perf.c and so util.c is as > sensible a location. Having this be a global is something of an > encapsulation fail, but cleaning that up wasn't the point of these > patches. The variable is used in util, so reaching up a directory to > get it feels somewhat unnatural. > > perf util: Move perf_guest/host declarations > > As with input_name. > > Thanks, > Ian