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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 CEF03C433F5 for ; Tue, 14 Sep 2021 21:36:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B020D61183 for ; Tue, 14 Sep 2021 21:36:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234860AbhINVhV (ORCPT ); Tue, 14 Sep 2021 17:37:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:44248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232047AbhINVhU (ORCPT ); Tue, 14 Sep 2021 17:37:20 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 38B916113B; Tue, 14 Sep 2021 21:36:02 +0000 (UTC) Date: Tue, 14 Sep 2021 17:35:55 -0400 From: Steven Rostedt To: Jiri Olsa Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Subject: Re: [PATCH 6/8] ftrace: Add multi direct register/unregister interface Message-ID: <20210914173555.056cd20c@oasis.local.home> In-Reply-To: <20210831095017.412311-7-jolsa@kernel.org> References: <20210831095017.412311-1-jolsa@kernel.org> <20210831095017.412311-7-jolsa@kernel.org> X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 31 Aug 2021 11:50:15 +0200 Jiri Olsa wrote: > Adding interface to register multiple direct functions > within single call. Adding following functions: > > register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) > unregister_ftrace_direct_multi(struct ftrace_ops *ops) > > The register_ftrace_direct_multi registers direct function (addr) > with all functions in ops filter. The ops filter can be updated > before with ftrace_set_filter_ip calls. > > All requested functions must not have direct function currently > registered, otherwise register_ftrace_direct_multi will fail. > > The unregister_ftrace_direct_multi unregisters ops related direct > functions. > > Signed-off-by: Jiri Olsa > --- > include/linux/ftrace.h | 11 ++++ > kernel/trace/ftrace.c | 111 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 122 insertions(+) > > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index d399621a67ee..e40b5201c16e 100644 > --- a/include/linux/ftrace.h > +++ b/include/linux/ftrace.h > @@ -316,7 +316,10 @@ int ftrace_modify_direct_caller(struct ftrace_func_entry *entry, > unsigned long old_addr, > unsigned long new_addr); > 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); > #else > +struct ftrace_ops; > # define ftrace_direct_func_count 0 > static inline int register_ftrace_direct(unsigned long ip, unsigned long addr) > { > @@ -346,6 +349,14 @@ static inline unsigned long ftrace_find_rec_direct(unsigned long ip) > { > return 0; > } > +static inline int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) > +{ > + return -ENODEV; > +} > +static inline int unregister_ftrace_direct_multi(struct ftrace_ops *ops) > +{ > + 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 c60217d81040..7243769493c9 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -5407,6 +5407,117 @@ int modify_ftrace_direct(unsigned long ip, > return ret; > } > EXPORT_SYMBOL_GPL(modify_ftrace_direct); > + > +#define MULTI_FLAGS (FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_DIRECT | \ > + FTRACE_OPS_FL_SAVE_REGS) > + > +static int check_direct_multi(struct ftrace_ops *ops) > +{ > + if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) > + return -EINVAL; > + if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS) > + return -EINVAL; > + return 0; > +} > + Needs kernel doc comments as this is an interface outside this file. > +int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr) > +{ > + struct ftrace_hash *hash, *free_hash = NULL; > + struct ftrace_func_entry *entry, *new; > + int err = -EBUSY, size, i; > + > + if (ops->func || ops->trampoline) > + return -EINVAL; > + if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) > + return -EINVAL; > + if (ops->flags & FTRACE_OPS_FL_ENABLED) > + return -EINVAL; > + > + hash = ops->func_hash->filter_hash; > + if (ftrace_hash_empty(hash)) > + return -EINVAL; > + > + mutex_lock(&direct_mutex); > + > + /* Make sure requested entries are not already registered.. */ > + size = 1 << hash->size_bits; > + for (i = 0; i < size; i++) { > + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { > + if (ftrace_find_rec_direct(entry->ip)) > + goto out_unlock; > + } > + } > + > + /* ... and insert them to direct_functions hash. */ > + err = -ENOMEM; > + for (i = 0; i < size; i++) { > + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { > + new = ftrace_add_rec_direct(entry->ip, addr, &free_hash); > + if (!new) > + goto out_remove; > + entry->direct = addr; > + } > + } > + > + ops->func = call_direct_funcs; > + ops->flags = MULTI_FLAGS; > + ops->trampoline = FTRACE_REGS_ADDR; > + > + err = register_ftrace_function(ops); > + > + out_remove: > + if (err) { The below code: > + for (i = 0; i < size; i++) { > + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { > + new = __ftrace_lookup_ip(direct_functions, entry->ip); > + if (new) { > + remove_hash_entry(direct_functions, new); > + kfree(new); > + } > + } > + } is identical to code below. > + } > + > + out_unlock: > + mutex_unlock(&direct_mutex); > + > + if (free_hash) { > + synchronize_rcu_tasks(); > + free_ftrace_hash(free_hash); > + } > + return err; > +} > +EXPORT_SYMBOL_GPL(register_ftrace_direct_multi); > + Should have kernel doc as well. > +int unregister_ftrace_direct_multi(struct ftrace_ops *ops) > +{ > + struct ftrace_hash *hash = ops->func_hash->filter_hash; > + struct ftrace_func_entry *entry, *new; > + int err, size, i; > + > + if (check_direct_multi(ops)) > + return -EINVAL; > + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) > + return -EINVAL; > + > + mutex_lock(&direct_mutex); > + err = unregister_ftrace_function(ops); > + > + size = 1 << hash->size_bits; > + for (i = 0; i < size; i++) { > + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { > + new = __ftrace_lookup_ip(direct_functions, entry->ip); > + if (new) { > + remove_hash_entry(direct_functions, new); > + kfree(new); > + } > + } > + } Would probably make sense to turn this into a static inline helper. -- Steve > + > + mutex_unlock(&direct_mutex); > + return err; > +} > +EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi); > #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ > > /**