From patchwork Thu Jun 2 19:37:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12868094 X-Patchwork-Delegate: bpf@iogearbox.net 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F166C43334 for ; Thu, 2 Jun 2022 19:43:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238925AbiFBTnO convert rfc822-to-8bit (ORCPT ); Thu, 2 Jun 2022 15:43:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238938AbiFBTm4 (ORCPT ); Thu, 2 Jun 2022 15:42:56 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AA312AD8 for ; Thu, 2 Jun 2022 12:42:56 -0700 (PDT) Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 252FLKdG021156 for ; Thu, 2 Jun 2022 12:42:55 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3ge9m2sj5j-10 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 02 Jun 2022 12:42:55 -0700 Received: from twshared19572.14.frc2.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.28; Thu, 2 Jun 2022 12:42:49 -0700 Received: by devbig932.frc1.facebook.com (Postfix, from userid 4523) id 97C5586C00CE; Thu, 2 Jun 2022 12:37:15 -0700 (PDT) From: Song Liu To: , , CC: , , , , , , , Song Liu Subject: [PATCH v2 bpf-next 2/5] ftrace: add modify_ftrace_direct_multi_nolock Date: Thu, 2 Jun 2022 12:37:03 -0700 Message-ID: <20220602193706.2607681-3-song@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220602193706.2607681-1-song@kernel.org> References: <20220602193706.2607681-1-song@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: PLGzm1rwk8-YE5kQoHR_QLhgEFQATJqs X-Proofpoint-ORIG-GUID: PLGzm1rwk8-YE5kQoHR_QLhgEFQATJqs X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-02_05,2022-06-02_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This is similar to modify_ftrace_direct_multi, but does not acquire direct_mutex. This is useful when direct_mutex is already locked by the user. Signed-off-by: Song Liu --- include/linux/ftrace.h | 5 +++ kernel/trace/ftrace.c | 85 ++++++++++++++++++++++++++++++------------ 2 files changed, 67 insertions(+), 23 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 820500430eae..9023bf69f675 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -343,6 +343,7 @@ unsigned long ftrace_find_rec_direct(unsigned long ip); int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr); int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr); int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr); +int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr); #else struct ftrace_ops; @@ -387,6 +388,10 @@ static inline int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned lo { return -ENODEV; } +static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr) +{ + return -ENODEV; +} #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index afe782ae28d3..6a419f6bbbf0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5601,22 +5601,8 @@ int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) } EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi); -/** - * modify_ftrace_direct_multi - Modify an existing direct 'multi' call - * to call something else - * @ops: The address of the struct ftrace_ops object - * @addr: The address of the new trampoline to call at @ops functions - * - * This is used to unregister currently registered direct caller and - * register new one @addr on functions registered in @ops object. - * - * Note there's window between ftrace_shutdown and ftrace_startup calls - * where there will be no callbacks called. - * - * Returns: zero on success. Non zero on error, which includes: - * -EINVAL - The @ops object was not properly registered. - */ -int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) +static int +__modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) { struct ftrace_hash *hash; struct ftrace_func_entry *entry, *iter; @@ -5627,12 +5613,8 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) int i, size; int err; - if (check_direct_multi(ops)) + if (WARN_ON_ONCE(!mutex_is_locked(&direct_mutex))) return -EINVAL; - if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) - return -EINVAL; - - mutex_lock(&direct_mutex); /* Enable the tmp_ops to have the same functions as the direct ops */ ftrace_ops_init(&tmp_ops); @@ -5640,7 +5622,7 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) err = register_ftrace_function(&tmp_ops); if (err) - goto out_direct; + return err; /* * Now the ftrace_ops_list_func() is called to do the direct callers. @@ -5664,7 +5646,64 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) /* Removing the tmp_ops will add the updated direct callers to the functions */ unregister_ftrace_function(&tmp_ops); - out_direct: + return err; +} + +/** + * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call + * to call something else + * @ops: The address of the struct ftrace_ops object + * @addr: The address of the new trampoline to call at @ops functions + * + * This is used to unregister currently registered direct caller and + * register new one @addr on functions registered in @ops object. + * + * Note there's window between ftrace_shutdown and ftrace_startup calls + * where there will be no callbacks called. + * + * Caller should already have direct_mutex locked, so we don't lock + * direct_mutex here. + * + * Returns: zero on success. Non zero on error, which includes: + * -EINVAL - The @ops object was not properly registered. + */ +int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr) +{ + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + + return __modify_ftrace_direct_multi(ops, addr); +} +EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock); + +/** + * modify_ftrace_direct_multi - Modify an existing direct 'multi' call + * to call something else + * @ops: The address of the struct ftrace_ops object + * @addr: The address of the new trampoline to call at @ops functions + * + * This is used to unregister currently registered direct caller and + * register new one @addr on functions registered in @ops object. + * + * Note there's window between ftrace_shutdown and ftrace_startup calls + * where there will be no callbacks called. + * + * Returns: zero on success. Non zero on error, which includes: + * -EINVAL - The @ops object was not properly registered. + */ +int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) +{ + int err; + + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + + mutex_lock(&direct_mutex); + err = __modify_ftrace_direct_multi(ops, addr); mutex_unlock(&direct_mutex); return err; }