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 X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 288DBC2D0D1 for ; Sun, 29 Dec 2019 14:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3815206E4 for ; Sun, 29 Dec 2019 14:38:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577630287; bh=hLi/NDdw8t3mK/RZZD5iTE8DCDRxcIYMfepankT+yIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SheaOlc3ojm8pcHPpzIS9d9uRghs6dYUkazWZCGbnO3jWEU+mUXCvvqj/1uSQs9uG 353BkytgEw6TbsiRVWdoKcf8pB6SNY9LoW6Dl/QKCFa0y6L9z8sTZqTCdTXBnFCka4 mUyagcVz+pvqOzQKlFmMordH3ZRYCBzR3sQrG/dg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726816AbfL2OiG convert rfc822-to-8bit (ORCPT ); Sun, 29 Dec 2019 09:38:06 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:47789 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726798AbfL2OiE (ORCPT ); Sun, 29 Dec 2019 09:38:04 -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-24-BUO75DSvOymR2akmbqlz0A-1; Sun, 29 Dec 2019 09:38:00 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1D1F21005502; Sun, 29 Dec 2019 14:37:59 +0000 (UTC) Received: from krava.redhat.com (ovpn-204-25.brq.redhat.com [10.40.204.25]) by smtp.corp.redhat.com (Postfix) with ESMTP id 86B405DA7D; Sun, 29 Dec 2019 14:37:56 +0000 (UTC) From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Andrii Nakryiko , Yonghong Song , Martin KaFai Lau , Jakub Kicinski , David Miller Subject: [PATCH 5/5] bpf: Allow to resolve bpf trampoline in unwind Date: Sun, 29 Dec 2019 15:37:40 +0100 Message-Id: <20191229143740.29143-6-jolsa@kernel.org> In-Reply-To: <20191229143740.29143-1-jolsa@kernel.org> References: <20191229143740.29143-1-jolsa@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: BUO75DSvOymR2akmbqlz0A-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When unwinding the stack we need to identify each address to successfully continue. Adding latch tree to keep trampolines for quick lookup during the unwind. Signed-off-by: Jiri Olsa --- include/linux/bpf.h | 6 ++++++ kernel/bpf/core.c | 2 ++ kernel/bpf/trampoline.c | 35 +++++++++++++++++++++++++++++++++++ 3 files changed, 43 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index b14e51d56a82..66825c821ac9 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -470,6 +470,7 @@ struct bpf_trampoline { /* Executable image of trampoline */ void *image; u64 selector; + struct latch_tree_node tnode; }; #define BPF_DISPATCHER_MAX 48 /* Fits in 2048B */ @@ -502,6 +503,7 @@ struct bpf_trampoline *bpf_trampoline_lookup(u64 key); int bpf_trampoline_link_prog(struct bpf_prog *prog); int bpf_trampoline_unlink_prog(struct bpf_prog *prog); void bpf_trampoline_put(struct bpf_trampoline *tr); +bool is_bpf_trampoline(void *addr); void *bpf_jit_alloc_exec_page(void); #define BPF_DISPATCHER_INIT(name) { \ .mutex = __MUTEX_INITIALIZER(name.mutex), \ @@ -555,6 +557,10 @@ static inline void bpf_trampoline_put(struct bpf_trampoline *tr) {} static inline void bpf_dispatcher_change_prog(struct bpf_dispatcher *d, struct bpf_prog *from, struct bpf_prog *to) {} +static inline bool is_bpf_trampoline(void *addr) +{ + return false; +} #endif struct bpf_func_info_aux { diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 29d47aae0dd1..63a515b5aa7b 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -704,6 +704,8 @@ bool is_bpf_text_address(unsigned long addr) rcu_read_lock(); ret = bpf_prog_kallsyms_find(addr) != NULL; + if (!ret) + ret = is_bpf_trampoline((void*) addr); rcu_read_unlock(); return ret; diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 505f4e4b31d2..4b5f0d0b0072 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -4,16 +4,44 @@ #include #include #include +#include /* btf_vmlinux has ~22k attachable functions. 1k htab is enough. */ #define TRAMPOLINE_HASH_BITS 10 #define TRAMPOLINE_TABLE_SIZE (1 << TRAMPOLINE_HASH_BITS) static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE]; +static struct latch_tree_root tree __cacheline_aligned; /* serializes access to trampoline_table */ static DEFINE_MUTEX(trampoline_mutex); +static __always_inline bool tree_less(struct latch_tree_node *a, + struct latch_tree_node *b) +{ + struct bpf_trampoline *ta = container_of(a, struct bpf_trampoline, tnode); + struct bpf_trampoline *tb = container_of(b, struct bpf_trampoline, tnode); + + return ta->image < tb->image; +} + +static __always_inline int tree_comp(void *addr, struct latch_tree_node *n) +{ + struct bpf_trampoline *tr = container_of(n, struct bpf_trampoline, tnode); + + if (addr < tr->image) + return -1; + if (addr >= tr->image + PAGE_SIZE) + return 1; + + return 0; +} + +static const struct latch_tree_ops tree_ops = { + .less = tree_less, + .comp = tree_comp, +}; + void *bpf_jit_alloc_exec_page(void) { void *image; @@ -30,6 +58,11 @@ void *bpf_jit_alloc_exec_page(void) return image; } +bool is_bpf_trampoline(void *addr) +{ + return latch_tree_find(addr, &tree, &tree_ops) != NULL; +} + struct bpf_trampoline *bpf_trampoline_lookup(u64 key) { struct bpf_trampoline *tr; @@ -65,6 +98,7 @@ 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; + latch_tree_insert(&tr->tnode, &tree, &tree_ops); out: mutex_unlock(&trampoline_mutex); return tr; @@ -252,6 +286,7 @@ void bpf_trampoline_put(struct bpf_trampoline *tr) goto out; bpf_jit_free_exec(tr->image); hlist_del(&tr->hlist); + latch_tree_erase(&tr->tnode, &tree, &tree_ops); kfree(tr); out: mutex_unlock(&trampoline_mutex); -- 2.21.1