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 2D1262C2ABF; Wed, 3 Dec 2025 08:24:54 +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=1764750295; cv=none; b=kQ36BgJScaZLN4GYlzBfdAig4r008ZZ831Q3mwm1rIUMR8n+1DvkHpA7CWC1dAKY45iZmakAdm2J5VCpIM9zOlI5YO/HhHKbx48E1qZewrKVG6lzOROI+cYAJOsRFUN9tn9pW5TUuMl7cxfTJW21HyoV5rX6tuUJjLrLzbXc5Ug= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764750295; c=relaxed/simple; bh=Emu7TZrB/ba81eue9Hl9bE7eY0YOVtdlGr12xVhmDKI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=clIjQ1rroqJvSbzJFs1DNqjlZS3fEcE6OdIRQeVYaBmeUcdGhNpSel4QmSwO2p12b8ZzjqEOnvPoLxRa1z2e/SlrHDs4FkD9TrZPmggFOQHZtA+r65h7f0qG6I0FTwdckBYycpuKK7d2ybAkPQX1mEJxZyftpDytbJhwd7Me5e0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sh8Fb7Im; 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="sh8Fb7Im" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF41BC4CEFB; Wed, 3 Dec 2025 08:24:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764750294; bh=Emu7TZrB/ba81eue9Hl9bE7eY0YOVtdlGr12xVhmDKI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sh8Fb7Im7xyYcTF2xrSNDJ2NMg2CvH8hTvagHrIIwdOmBBjhY+ouhMVsYfNhGk2Hc 8wlEN/thKFYSr/Qe8EpAl4Dkh7LEivEzKnbIB94aeD2tUNHmrzi80D65RiecIPrMbC RR/UoHEMP/6JttVuso8JnsC6m3y65TazU9ssVDErULtHVd196+ydU4+ZL+xH8rVHkT 5kE8+XWSG32xuaYsFCA3s3GLggL0XtV/LiUVQ3s6kK4uPvmwQ5bRuSNzlKzqMHZgIs UNNqEpevQ1nVyXVjMOx9s9Bfga0yPVYGerh8wk4Sue+ZGOrkR/6zSKPIuq+mtTfDWz ZZ3w7XutaBJoA== 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 4/9] ftrace: Add update_ftrace_direct_add function Date: Wed, 3 Dec 2025 09:23:57 +0100 Message-ID: <20251203082402.78816-5-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> 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 | 128 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 135 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 8c034b028af4..eb60d971ec1d 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -550,6 +550,8 @@ 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 @@ -576,6 +578,11 @@ 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 84aee9096a9e..1660a87547dd 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6249,6 +6249,134 @@ 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, i; + + size = hash_count(a) + hash_count(b); + if (size > 32) + size = 32; + + add = alloc_and_copy_ftrace_hash(fls(size), a); + if (!add) + goto error; + + size = 1 << b->size_bits; + for (i = 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + if (add_hash_entry_direct(add, entry->ip, entry->direct) == NULL) + goto error; + } + } + return add; + + error: + free_ftrace_hash(add); + return NULL; +} + +int update_ftrace_direct_add(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 *entry; + int i, size, err = -EINVAL; + 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 (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; + old_direct_functions = direct_functions; + + /* 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(old_direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + 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; + old_filter_hash = new_filter_hash; + + /* cleanup for possible another register call */ + ops->func = NULL; + ops->trampoline = 0; + } + } 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 + */ + old_filter_hash = new_filter_hash; + } + + 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); + if (old_filter_hash) + free_ftrace_hash(old_filter_hash); + + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ /** -- 2.52.0