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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9070ED1266D for ; Wed, 3 Dec 2025 08:25:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=c3wOOhoh4U6kkZR5EJfReRXdzhPERppHpS2Us2O4JNE=; b=VvJbkHBCJZ0SaRsWOF+LW3FdK5 Ss19ywiorOAPRCNIf8zA3C357B028QvjrglY7Y6gYI28kCdbuwyHU2oqNo2aTqoE/CH5kBarfQ6AQ +514Bzu03+dNLTgl5I6zDyTPkVoxKtzxBhJC5CZL7/NsMSsmO9JkRCLcFoXAf4PKr16kkpWi0/MlB YxVNNOOZqfWdCo5618VSscPO/CzvqJ32SZXXlPi6G0xwVkKNteF1DR7XQhLGd0yU/17ItLfY+ew6+ /xc7rXc/asBhPHC0cnaaQWf0M/9015neoysAOxsKlslp+PReTIO325D/Y/bL9S2aD9fFvae2Y+Qqn 0atKucWg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vQiAf-00000006Ikj-06hM; Wed, 03 Dec 2025 08:25:09 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vQiAb-00000006Iih-2mje for linux-arm-kernel@lists.infradead.org; Wed, 03 Dec 2025 08:25:07 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 5809840843; Wed, 3 Dec 2025 08:25:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B739C116B1; Wed, 3 Dec 2025 08:25:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764750305; bh=sjHj3Ruu15dXTg7oJ7kSKcH775GCTI2sTuBpJwydfrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=re5sBgVv5u2FxUbViNNVr8qEsmV76iUDcVhnyxz22MjNNnyD5d+Lq0zVbw/S7iQZ3 4D8eYze6f14hAhcIL9I8Ahpv+DfNaU7MS7mKvL5fnBWGTd+M0/jMZ/w7Q7srMYkhNU InJisV06XiUpltFa9ekDYXItUweDJHmWtWnZE2sZ8FgPUx5lQaS3i9LEx1QBsIoGa0 oCBjBq/CCFBXy6D2FUMoULQrPfeVsu8qT8M3Rl7qfBkqx4EjLwXwvkRvvs2Kr86bbO UOf5KFBtBpnWVehQxggYO/PMXgGMCiY8Jsosqjk4KEQ/rqXKojKsIgIGj3ZplKGSPu O6Y1a9Bvn7XkA== From: Jiri Olsa To: Steven Rostedt , Florent Revest , Mark Rutland Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Menglong Dong , Song Liu Subject: [PATCHv4 bpf-next 5/9] ftrace: Add update_ftrace_direct_del function Date: Wed, 3 Dec 2025 09:23:58 +0100 Message-ID: <20251203082402.78816-6-jolsa@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251203082402.78816-1-jolsa@kernel.org> References: <20251203082402.78816-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251203_002505_746311_3FFEA4BA X-CRM114-Status: GOOD ( 19.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Adding update_ftrace_direct_del function that removes all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current unregister_ftrace_direct is - hash argument that allows to unregister multiple ip -> direct entries at once - we can call update_ftrace_direct_del multiple times on the same ftrace_ops object, becase we do not need to unregister all entries at once, we can do it gradualy with the help of ftrace_update_ops function This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 6 +++ kernel/trace/ftrace.c | 113 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 119 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index eb60d971ec1d..bac9dd784826 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -551,6 +551,7 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr); int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash); +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash); void ftrace_stub_direct_tramp(void); @@ -583,6 +584,11 @@ static inline int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace return -ENODEV; } +static inline int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + return -ENODEV; +} + /* * This must be implemented by the architecture. * It is the way the ftrace direct_ops helper, when called diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1660a87547dd..01e830be20e3 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6377,6 +6377,119 @@ int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) return err; } +/** + * hash_sub - substracts @b from @a and returns the result + * @a: struct ftrace_hash object + * @b: struct ftrace_hash object + * + * Returns struct ftrace_hash object on success, NULL on error. + */ +static struct ftrace_hash *hash_sub(struct ftrace_hash *a, struct ftrace_hash *b) +{ + struct ftrace_func_entry *entry, *del; + struct ftrace_hash *sub; + int size, i; + + sub = alloc_and_copy_ftrace_hash(a->size_bits, a); + if (!sub) + goto error; + + size = 1 << b->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + del = __ftrace_lookup_ip(sub, entry->ip); + if (WARN_ON_ONCE(!del)) + goto error; + remove_hash_entry(sub, del); + kfree(del); + } + } + return sub; + + error: + free_ftrace_hash(sub); + return NULL; +} + +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + struct ftrace_hash *old_direct_functions = NULL, *new_direct_functions = NULL; + struct ftrace_hash *old_filter_hash = NULL, *new_filter_hash = NULL; + struct ftrace_func_entry *del, *entry; + unsigned long size, i; + int err = -EINVAL; + + if (!hash_count(hash)) + return -EINVAL; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions == EMPTY_HASH) + return -EINVAL; + + mutex_lock(&direct_mutex); + + old_filter_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; + old_direct_functions = direct_functions; + + if (!hash_count(old_filter_hash)) + goto out_unlock; + + /* Make sure requested entries are already registered. */ + size = 1 << hash->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + del = __ftrace_lookup_ip(direct_functions, entry->ip); + if (!del || del->direct != entry->direct) + goto out_unlock; + } + } + + err = -ENOMEM; + new_filter_hash = hash_sub(old_filter_hash, hash); + if (!new_filter_hash) + goto out_unlock; + + new_direct_functions = hash_sub(old_direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + /* If there's nothing left, we need to unregister the ops. */ + if (ftrace_hash_empty(new_filter_hash)) { + err = unregister_ftrace_function(ops); + if (!err) { + /* cleanup for possible another register call */ + ops->func = NULL; + ops->trampoline = 0; + ftrace_free_filter(ops); + ops->func_hash->filter_hash = NULL; + } + } else { + err = ftrace_update_ops(ops, new_filter_hash, EMPTY_HASH); + /* + * new_filter_hash is dup-ed, so we need to release it anyway, + * old_filter_hash either stays on error or is released already + */ + } + + if (err) { + /* reset direct_functions and free the new one */ + old_direct_functions = new_direct_functions; + } else { + rcu_assign_pointer(direct_functions, new_direct_functions); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (old_direct_functions && old_direct_functions != EMPTY_HASH) + call_rcu_tasks(&old_direct_functions->rcu, register_ftrace_direct_cb); + free_ftrace_hash(new_filter_hash); + + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** -- 2.52.0