From nobody Tue Dec 16 09:01:45 2025 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (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 5EE9623D2B6 for ; Wed, 9 Jul 2025 21:40:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752097243; cv=none; b=GdRJOGHoRovchbi9Nl8DO40nGT8R2va0VcgNo1Lmxs8hZPLMWuDXMjjquQSfZTGGQEalAOGB9FbA22hZf0vAwifY+J+UcIRd2kIx0Z9Rg53fBZa85ZMYkBPvPHzKO3Aj+bqxQlZVOuZD8UtrYh6w3BB+yrVCRMcOIaD0MVKZq34= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752097243; c=relaxed/simple; bh=8+fzwKbYyh0HgEc4+oNZYk8ZhmbZCi8quzaYQRyDMRY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=KYpDEaL5qo5mNRPeJDxs3OUeLGHuLssDZgRXk8jyQeJ2r8zYnKEcex+/e4ArkDc2zV6S+Ld0XE6eHqi08chMDWdfUjYVFgt3YFJd+Rk8Xev0e7pPpAU6YJ99iy1LEy/TrhAzJete8o348DBO+yCkV9zdHulsNqYYRblsV/+TdgI= 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=rcZzNcEr; arc=none smtp.client-ip=209.85.215.201 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="rcZzNcEr" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-b321087b1cdso367431a12.2 for ; Wed, 09 Jul 2025 14:40:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1752097242; x=1752702042; 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=rcZzNcErVyUuTI4nsH102cf2L0gjFgkGyi/lkxRnA6lyu0g5JYxVWkdTUKCiNsDB+b oUR/bYiFVEeWlCFFSH1FATj7QVs2+ryEDDtknIDMQil7DOFSJhDG15e3X3s+IVzegF6s OF/SYE+tSvZhQm4/xxY+nxuvBJqsknwr4K9A5SrdOgm62HYfXl3EaoH/Bd36Idr4X2OA kUZB1wDkjMYWiNgmTln85kE+/IH/kTyn+2m/felf7HY6f/U2A5JT4WYWw5QdQIeC8vKY fRke8VBXAA7DEEucWqh3oTNwYFyI2jsOLhPsjIqj+c1jgvkKn4KUlypZ5uL73n1zN40r ntgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752097242; x=1752702042; 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=xS1mBxB7V5GDyB+I3oEqN9EDynZXZ/kxnxyUMgpseBkZacKi7Rrc4e2z2bMnKJhZlR aJCrt3aQnRkOoJ7dyLRgCgfNwmoTmVLv7zHSS57KB8t8clMRfwQ/C3fPjbv7pk6irr1X KVdH37vQNIPVQFuxGji6dmXGTpfikzM0ODay0aX0/QPzYrR+wjlApC8LtfYPVfm9G8ag ZaJ8lCTFLFlwfSoIk6mGwOfYI/e3hpvMhHVxyYLCvcAN1nzYyAsFBlRI2EQ4cUEncvA5 dDSkt46yPmmQnx7dTg85IRM7tOW2IcJFyL3TWIt6rHX5ACXV+49KIWxcICopMCYqIxW2 bLyw== X-Forwarded-Encrypted: i=1; AJvYcCWzQHF0J/fj3IzmB6IrvumUuIeaLRzdecLzIx1p2NVCeZjpt9YvwOAd9hLnfd0la/kK4nOX76lgARoHDz0=@vger.kernel.org X-Gm-Message-State: AOJu0YzHYLmDffCooIAKGDjQb5+/ssykGaLoET63HXEDU/5yGx9yrRqy ZOUNkhqkwAuEbIKt6yLL3DXp+sm4v8IomidpKa69xNP9jxVLtJ3LSV0iENtOza9FexICL+D5HW6 youhpQFAT5Q== X-Google-Smtp-Source: AGHT+IEBtciJsh8xRDvIq+Sgsncs0zNYJD3rc0jF/WOqfdg3f+RccueHuYWIQOWwgAEZQpSuy2QQRcospvlu X-Received: from pgdk7.prod.google.com ([2002:a05:6a02:5467:b0:b31:c7e5:6664]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:7489:b0:220:9c00:6879 with SMTP id adf61e73a8af0-230045c6577mr308556637.17.1752097241840; Wed, 09 Jul 2025 14:40:41 -0700 (PDT) Date: Wed, 9 Jul 2025 14:40:21 -0700 In-Reply-To: <20250709214029.1769089-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250709214029.1769089-1-irogers@google.com> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Message-ID: <20250709214029.1769089-5-irogers@google.com> Subject: [PATCH v1 04/12] 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 , 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