From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D003317701; Tue, 30 Dec 2025 14:51:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767106262; cv=none; b=O/BwIRyeDwz0OGkn+fuFfdU7/FKoXmH4QP3FtDNsI/ERdiT0w4s3i1ABpuI1bBOn9pWvxvJppu1ZhuLd1tuc/etAhAQM3CvU9tDRtyCIZokkn2ERWjMfDxIWv1Jv1wG5iwayRb8WFUj4WpdPT2xH269mnS5sGW6EVeMGks0+hhc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767106262; c=relaxed/simple; bh=nhPjtyH+1jx9XO4H6psdQcnvbEZVvVYR0jh9UFg5wNE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mYhFAhvdKLZ7Ys/uQDYosEg8OAnW497Y0fIWNkIsPPLS3h9AQmwbQJ2qJmIZljFNoaFH4mYkwF5dY4aWN8TxFfCtTmT2v7gXYzaA1DghX7VCSb5lWKabys2aM4NySam6z7IwcUseuRzdPq9eetGiyWA7nLaEOhhwajCSMl2xTPg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hK58HmHH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hK58HmHH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06F0BC4CEFB; Tue, 30 Dec 2025 14:50:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767106262; bh=nhPjtyH+1jx9XO4H6psdQcnvbEZVvVYR0jh9UFg5wNE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hK58HmHHYArQaWG33mxcDgy2hjSUM3gHA2uSaOIq1l+XmgTBzPbE8EA3sT4Wr0lPI b+np/Oc3ohRyMaWK9q0GvnXNgXlK5C8sE/orEDh76ah0il2mpKbaodErcRXraR9gkV nxWojG7OJ+e3N3CBs3vIXHq69QVp3Cp1vWg6rgkcXZJ+1jvFSHhZpnATkF3uydEBhe OnSCJhWQVnblaXFZSykVGAZl7LDcelYSSUid8j3wD0/s7m1HwYqnUwczAy4EP+0yBk CJ6jbaf6PFdcxsUCrk8jZsbJVVWhfefoSjWPsuZ8IINfTiRyqkfhJzUdbUADKE9fRr ++uySceZaKUvw== 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: [PATCHv6 bpf-next 4/9] ftrace: Add update_ftrace_direct_add function Date: Tue, 30 Dec 2025 15:50:05 +0100 Message-ID: <20251230145010.103439-5-jolsa@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251230145010.103439-1-jolsa@kernel.org> References: <20251230145010.103439-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Adding update_ftrace_direct_add function that adds all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current register_ftrace_direct is - hash argument that allows to register multiple ip -> direct entries at once - we can call update_ftrace_direct_add multiple times on the same ftrace_ops object, becase after first registration with register_ftrace_function_nolock, it uses ftrace_update_ops to update the ftrace_ops object 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 | 7 +++ kernel/trace/ftrace.c | 140 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 147 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 472f2d8a4c0f..f0fcff389061 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -543,6 +543,8 @@ int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr, 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); + void ftrace_stub_direct_tramp(void); #else @@ -569,6 +571,11 @@ static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned l return -ENODEV; } +static inline int update_ftrace_direct_add(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 3ca3aee5f886..3d1170da1bb8 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6275,6 +6275,146 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr) return err; } EXPORT_SYMBOL_GPL(modify_ftrace_direct); + +static unsigned long hash_count(struct ftrace_hash *hash) +{ + return hash ? hash->count : 0; +} + +/** + * hash_add - adds two struct ftrace_hash 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_add(struct ftrace_hash *a, struct ftrace_hash *b) +{ + struct ftrace_func_entry *entry; + struct ftrace_hash *add; + int size; + + size = hash_count(a) + hash_count(b); + if (size > 32) + size = 32; + + add = alloc_and_copy_ftrace_hash(fls(size), a); + if (!add) + return NULL; + + size = 1 << b->size_bits; + for (int i = 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + if (add_ftrace_hash_entry_direct(add, entry->ip, entry->direct) == NULL) { + free_ftrace_hash(add); + return NULL; + } + } + } + return add; +} + +/** + * update_ftrace_direct_add - Updates @ops by adding direct + * callers provided in @hash + * @ops: The address of the struct ftrace_ops object + * @hash: The address of the struct ftrace_hash object + * + * This is used to add custom direct callers (ip -> addr) to @ops, + * specified in @hash. The @ops will be either registered or updated. + * + * Returns: zero on success. Non zero on error, which includes: + * -EINVAL - The @hash is empty + */ +int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *hash) +{ + struct ftrace_hash *old_direct_functions = NULL; + struct ftrace_hash *new_direct_functions; + struct ftrace_hash *old_filter_hash; + struct ftrace_hash *new_filter_hash = NULL; + struct ftrace_func_entry *entry; + int err = -EINVAL; + int size; + bool reg; + + if (!hash_count(hash)) + return -EINVAL; + + mutex_lock(&direct_mutex); + + /* Make sure requested entries are not already registered. */ + size = 1 << hash->size_bits; + for (int i = 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + if (__ftrace_lookup_ip(direct_functions, entry->ip)) + goto out_unlock; + } + } + + old_filter_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; + + /* If there's nothing in filter_hash we need to register the ops. */ + reg = hash_count(old_filter_hash) == 0; + if (reg) { + if (ops->func || ops->trampoline) + goto out_unlock; + if (ops->flags & FTRACE_OPS_FL_ENABLED) + goto out_unlock; + } + + err = -ENOMEM; + new_filter_hash = hash_add(old_filter_hash, hash); + if (!new_filter_hash) + goto out_unlock; + + new_direct_functions = hash_add(direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + old_direct_functions = direct_functions; + rcu_assign_pointer(direct_functions, new_direct_functions); + + if (reg) { + ops->func = call_direct_funcs; + ops->flags |= MULTI_FLAGS; + ops->trampoline = FTRACE_REGS_ADDR; + ops->local_hash.filter_hash = new_filter_hash; + + err = register_ftrace_function_nolock(ops); + if (err) { + /* restore old filter on error */ + ops->local_hash.filter_hash = old_filter_hash; + + /* cleanup for possible another register call */ + ops->func = NULL; + ops->trampoline = 0; + } else { + new_filter_hash = old_filter_hash; + } + } 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 already released + */ + } + + if (err) { + /* reset direct_functions and free the new one */ + rcu_assign_pointer(direct_functions, old_direct_functions); + old_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