From nobody Tue Oct 7 10:31:44 2025 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0CB9530749D for ; Thu, 10 Jul 2025 23:51:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752191516; cv=none; b=izFFra/Ku/Qh0g8a+YK+16o1wmTteXmBAUL/1Pwqu3AfX2bLRptBGauV6cBaFX4VuJS0Er8V4mY8W9k0YtE7mwIgBljknbYhVDFk2lQvqNnyKrQysXd2Q0XwcUk78//y36kV6Xl3Jzv6c4VyUajXLPxUIfwdjzO7cT+QW00+n84= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752191516; c=relaxed/simple; bh=8+fzwKbYyh0HgEc4+oNZYk8ZhmbZCi8quzaYQRyDMRY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=Kdon57wBiZeS2fN1gCNixLnNSFLNjVoa1dLL9JkWfXpv/HOyVQhzKoka2lqTRmdl58F8bkZ8+Z9V0Jm+Y4Ex0QXB2oKIEDGmcsl4/mwZkSr4m32qlDKB/42oV7gZtthUoKtX05Odfdktrs8PpOiOnj6QtLmmjUQK9m8YveRQBvg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=kbK4XSok; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="kbK4XSok" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-31315427249so1388902a91.1 for ; Thu, 10 Jul 2025 16:51:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1752191514; x=1752796314; darn=vger.kernel.org; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=jB43BWOgr1OVnJk/vG7v3SNwpLjEdqHnInxVydle4NQ=; b=kbK4XSokMMpOfu3C4NT75FrWVKyi907FrU6rUGqmKYh0g/o6sXiRe79oZi1+fARaaM JPBmGIbhYA2uQ03JwhgCoEBgHuwn38O2viANakUw5MekoAQNk/yTbrMzv2DFNA6aKebq EBHpd7jiNDoyNMGoORYaMgVAgz21RpLv3VVIsIGQdkXsVTLqYBFbRlWFZAEMgvRFMcHI Cd9/cjEnvCg5Gu6t2vquEFvcIvKYHv6hprBlcZOpYXs20yJZ7S79sAX93mfoZ52MqilW erc44ptiPys+KiEcjWwot+Mht8yz2ynurfKplrYzmz2hChgNdaC4xfO5mFyXVfk7CISl 8jhQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752191514; x=1752796314; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=jB43BWOgr1OVnJk/vG7v3SNwpLjEdqHnInxVydle4NQ=; b=t1ndOd3KL7bZ5E22vdeBPvKNsDQylCohWr9mcijbxzDL+VGmu+whUKKUpIylP4wMy+ gEWdjbsz4DHGDnidXaBiXUgVqbNeeE2Que4xpCeUBiTI3Clm4qCj2jDhLGLEoSEiIavH 46+1NBiz94AUsRoHHydVkFm3omUQvJNY8uOVtx6rYDHHRl/KFldCIvlNxXt36xLkdIu+ LaGHEzzlw1EPeMc8q3gRhDdymPoTIkAgbSuocpsb1Mu04StytWf8bmOzdhutQUlLTfmz I79ZEBtjJ8NQgoqoAFIfshB5luDo8TniExynPfL26OMCUI43eltWQMMDUcCWIbmK+GUM NEwQ== X-Forwarded-Encrypted: i=1; AJvYcCWH+zzfm4mh6LceRAyskelPXoPtNndZvSBFBGQ+OhcE7vG5sdUBRc/e3jTN8m4MYciIhRmoFJIF1fvCtTY=@vger.kernel.org X-Gm-Message-State: AOJu0YwnY4xXjy1F3pljbuXxm+IU2bdvad/hN1EG5rxtNQXUr0cMUK/W W9/OvrsYkMMv6l/XqDkvJCdEEDwJn8lL3I7vN2KVa2qAKSeYk66kSg17heO1Hn0ZrHBZHEQ70uS FAyO1TtmfgQ== X-Google-Smtp-Source: AGHT+IFHzoDdAVLiVt9wqChVcdmJwG5lwune8sMQ5I/kskubztWTyZMq3w6w/iqjpi5C0lsgndQnJd7FY+BX X-Received: from pjbqi10.prod.google.com ([2002:a17:90b:274a:b0:311:a4ee:7c3d]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4c0d:b0:315:af43:12ee with SMTP id 98e67ed59e1d1-31c50e1763cmr185604a91.16.1752191514187; Thu, 10 Jul 2025 16:51:54 -0700 (PDT) Date: Thu, 10 Jul 2025 16:51:17 -0700 In-Reply-To: <20250710235126.1086011-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250710235126.1086011-1-irogers@google.com> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Message-ID: <20250710235126.1086011-5-irogers@google.com> Subject: [PATCH v2 04/13] perf pmu: Tolerate failure to read the type for wellknown PMUs From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , James Clark , Xu Yang , Howard Chu , "Dr. David Alan Gilbert" , Levi Yun , Andi Kleen , Thomas Richter , Weilin Wang , Tiezhu Yang , Gautam Menghani , Thomas Falcon , Chun-Tse Shao , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If sysfs isn't mounted then we may fail to read a PMU's type. In this situation resort to lookup of wellknown types. Only applies to software, tracepoint and breakpoint PMUs. Signed-off-by: Ian Rogers --- tools/perf/util/pmu.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index f795883c233f..23666883049d 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -1182,6 +1182,32 @@ int perf_pmu__init(struct perf_pmu *pmu, __u32 type,= const char *name) return 0; } =20 +static __u32 wellknown_pmu_type(const char *pmu_name) +{ + struct { + const char *pmu_name; + __u32 type; + } wellknown_pmus[] =3D { + { + "software", + PERF_TYPE_SOFTWARE + }, + { + "tracepoint", + PERF_TYPE_TRACEPOINT + }, + { + "breakpoint", + PERF_TYPE_BREAKPOINT + }, + }; + for (size_t i =3D 0; i < ARRAY_SIZE(wellknown_pmus); i++) { + if (!strcmp(wellknown_pmus[i].pmu_name, pmu_name)) + return wellknown_pmus[i].type; + } + return PERF_TYPE_MAX; +} + struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const= char *name, bool eager_load) { @@ -1201,8 +1227,12 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *= pmus, int dirfd, const char * that type value is successfully assigned (return 1). */ if (perf_pmu__scan_file_at(pmu, dirfd, "type", "%u", &pmu->type) !=3D 1) { - perf_pmu__delete(pmu); - return NULL; + /* Double check the PMU's name isn't wellknown. */ + pmu->type =3D wellknown_pmu_type(name); + if (pmu->type =3D=3D PERF_TYPE_MAX) { + perf_pmu__delete(pmu); + return NULL; + } } =20 /* --=20 2.50.0.727.gbf7dc18ff4-goog