From patchwork Thu Dec 7 18:54:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 13483831 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89245171F for ; Thu, 7 Dec 2023 10:55:00 -0800 (PST) Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3B7EKQdw031422 for ; Thu, 7 Dec 2023 10:54:59 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3uufqft7ha-9 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 07 Dec 2023 10:54:59 -0800 Received: from twshared29562.14.frc2.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.34; Thu, 7 Dec 2023 10:54:54 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id 37D2E3CC1CA38; Thu, 7 Dec 2023 10:54:50 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , , , , Subject: [PATCH bpf-next 3/8] libbpf: further decouple feature checking logic from bpf_object Date: Thu, 7 Dec 2023 10:54:38 -0800 Message-ID: <20231207185443.2297160-4-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231207185443.2297160-1-andrii@kernel.org> References: <20231207185443.2297160-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: y3HdkwJb8JP6MbEsQPoVEClEUenZiqF6 X-Proofpoint-GUID: y3HdkwJb8JP6MbEsQPoVEClEUenZiqF6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-07_15,2023-12-07_01,2023-05-22_02 X-Patchwork-Delegate: bpf@iogearbox.net Add feat_supported() helper that accepts feature cache instead of bpf_object. This allows low-level code in bpf.c to not know or care about higher-level concept of bpf_object, yet it will be able to utilize custom feature checking in cases where BPF token might influence the outcome. Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend --- tools/lib/bpf/bpf.c | 6 +++--- tools/lib/bpf/libbpf.c | 23 ++++++++++++++++------- tools/lib/bpf/libbpf_internal.h | 5 ++++- 3 files changed, 23 insertions(+), 11 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index f4e1da3c6d5f..120855ac6859 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -146,7 +146,7 @@ int bump_rlimit_memlock(void) struct rlimit rlim; /* if kernel supports memcg-based accounting, skip bumping RLIMIT_MEMLOCK */ - if (memlock_bumped || kernel_supports(NULL, FEAT_MEMCG_ACCOUNT)) + if (memlock_bumped || feat_supported(NULL, FEAT_MEMCG_ACCOUNT)) return 0; memlock_bumped = true; @@ -181,7 +181,7 @@ int bpf_map_create(enum bpf_map_type map_type, return libbpf_err(-EINVAL); attr.map_type = map_type; - if (map_name && kernel_supports(NULL, FEAT_PROG_NAME)) + if (map_name && feat_supported(NULL, FEAT_PROG_NAME)) libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name)); attr.key_size = key_size; attr.value_size = value_size; @@ -265,7 +265,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type, attr.kern_version = OPTS_GET(opts, kern_version, 0); attr.prog_token_fd = OPTS_GET(opts, token_fd, 0); - if (prog_name && kernel_supports(NULL, FEAT_PROG_NAME)) + if (prog_name && feat_supported(NULL, FEAT_PROG_NAME)) libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name)); attr.license = ptr_to_u64(license); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a6b8d6f70918..af5e777efcbd 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -637,6 +637,7 @@ struct elf_state { }; struct usdt_manager; +struct kern_feature_cache; struct bpf_object { char name[BPF_OBJ_NAME_LEN]; @@ -5063,17 +5064,14 @@ static struct kern_feature_desc { }, }; -bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) +bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id) { struct kern_feature_desc *feat = &feature_probes[feat_id]; - struct kern_feature_cache *cache = &feature_cache; int ret; - if (obj && obj->gen_loader) - /* To generate loader program assume the latest kernel - * to avoid doing extra prog_load, map_create syscalls. - */ - return true; + /* assume global feature cache, unless custom one is provided */ + if (!cache) + cache = &feature_cache; if (READ_ONCE(cache->res[feat_id]) == FEAT_UNKNOWN) { ret = feat->probe(); @@ -5090,6 +5088,17 @@ bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED; } +bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) +{ + if (obj && obj->gen_loader) + /* To generate loader program assume the latest kernel + * to avoid doing extra prog_load, map_create syscalls. + */ + return true; + + return feat_supported(NULL, feat_id); +} + static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) { struct bpf_map_info map_info; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index b5d334754e5d..754a432335e4 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -360,8 +360,11 @@ enum kern_feature_id { __FEAT_CNT, }; -int probe_memcg_account(void); +struct kern_feature_cache; +bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id); bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id); + +int probe_memcg_account(void); int bump_rlimit_memlock(void); int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);