From patchwork Wed Feb 26 13:03:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 1245053 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48SGHC3gBYz9sRG for ; Thu, 27 Feb 2020 00:04:55 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727305AbgBZNEx convert rfc822-to-8bit (ORCPT ); Wed, 26 Feb 2020 08:04:53 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:51418 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726765AbgBZNEu (ORCPT ); Wed, 26 Feb 2020 08:04:50 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-274-dhq2BD2yOHin9Kg5dqRh8w-1; Wed, 26 Feb 2020 08:04:46 -0500 X-MC-Unique: dhq2BD2yOHin9Kg5dqRh8w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ACC3A801FB5; Wed, 26 Feb 2020 13:04:44 +0000 (UTC) Received: from krava.redhat.com (unknown [10.43.17.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id E418E19C7F; Wed, 26 Feb 2020 13:04:28 +0000 (UTC) From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Andrii Nakryiko , Yonghong Song , Song Liu , Martin KaFai Lau , Jakub Kicinski , David Miller , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , John Fastabend , Jesper Dangaard Brouer , Arnaldo Carvalho de Melo Subject: [PATCH 12/18] bpf: Add trampolines to kallsyms Date: Wed, 26 Feb 2020 14:03:39 +0100 Message-Id: <20200226130345.209469-13-jolsa@kernel.org> In-Reply-To: <20200226130345.209469-1-jolsa@kernel.org> References: <20200226130345.209469-1-jolsa@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Adding trampolines to kallsyms. It's displayed as bpf_trampoline_ [bpf] where ID is the BTF id of the trampoline function. Signed-off-by: Jiri Olsa Acked-by: Song Liu --- include/linux/bpf.h | 3 +++ kernel/bpf/trampoline.c | 38 +++++++++++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 76934893bccf..c216af89254f 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -502,6 +502,7 @@ struct bpf_trampoline { /* Executable image of trampoline */ void *image; u64 selector; + struct bpf_ksym ksym; }; #define BPF_DISPATCHER_MAX 48 /* Fits in 2048B */ @@ -573,6 +574,8 @@ struct bpf_image { #define BPF_IMAGE_SIZE (PAGE_SIZE - sizeof(struct bpf_image)) bool is_bpf_image_address(unsigned long address); void *bpf_image_alloc(void); +void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym); +void bpf_image_ksym_del(struct bpf_ksym *ksym); /* Called only from code, so there's no need for stubs. */ void bpf_ksym_add(struct bpf_ksym *ksym); void bpf_ksym_del(struct bpf_ksym *ksym); diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 6b264a92064b..4b0ae976a6eb 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -5,6 +5,7 @@ #include #include #include +#include /* dummy _ops. The verifier will operate on target program's ops. */ const struct bpf_verifier_ops bpf_extension_verifier_ops = { @@ -96,6 +97,22 @@ bool is_bpf_image_address(unsigned long addr) return ret; } +void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym) +{ + ksym->start = (unsigned long) data; + ksym->end = ksym->start + BPF_IMAGE_SIZE; + bpf_ksym_add(ksym); + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start, + BPF_IMAGE_SIZE, false, ksym->name); +} + +void bpf_image_ksym_del(struct bpf_ksym *ksym) +{ + bpf_ksym_del(ksym); + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start, + BPF_IMAGE_SIZE, true, ksym->name); +} + struct bpf_trampoline *bpf_trampoline_lookup(u64 key) { struct bpf_trampoline *tr; @@ -131,6 +148,7 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key) for (i = 0; i < BPF_TRAMP_MAX; i++) INIT_HLIST_HEAD(&tr->progs_hlist[i]); tr->image = image; + INIT_LIST_HEAD_RCU(&tr->ksym.lnode); out: mutex_unlock(&trampoline_mutex); return tr; @@ -267,6 +285,14 @@ static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(enum bpf_attach_type t) } } +static void bpf_trampoline_ksym_add(struct bpf_trampoline *tr) +{ + struct bpf_ksym *ksym = &tr->ksym; + + snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", tr->key); + bpf_image_ksym_add(tr->image, ksym); +} + int bpf_trampoline_link_prog(struct bpf_prog *prog) { enum bpf_tramp_prog_type kind; @@ -291,6 +317,10 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog) err = -EBUSY; goto out; } + /* With cnt == 0 image is not used (no symbol in kallsyms) + * and will not be used for BPF_PROG_TYPE_EXT prog type, + * so there's no symbol added for this case. + */ tr->extension_prog = prog; err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL, prog->bpf_func); @@ -311,7 +341,10 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog) if (err) { hlist_del(&prog->aux->tramp_hlist); tr->progs_cnt[kind]--; + goto out; } + if (cnt == 0) + bpf_trampoline_ksym_add(tr); out: mutex_unlock(&tr->mutex); return err; @@ -322,7 +355,7 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog) { enum bpf_tramp_prog_type kind; struct bpf_trampoline *tr; - int err; + int err, cnt; tr = prog->aux->trampoline; kind = bpf_attach_type_to_tramp(prog->expected_attach_type); @@ -336,6 +369,9 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog) } hlist_del(&prog->aux->tramp_hlist); tr->progs_cnt[kind]--; + cnt = tr->progs_cnt[BPF_TRAMP_FENTRY] + tr->progs_cnt[BPF_TRAMP_FEXIT]; + if (cnt == 0) + bpf_image_ksym_del(&tr->ksym); err = bpf_trampoline_update(prog->aux->trampoline); out: mutex_unlock(&tr->mutex);