From nobody Sat Feb 7 06:14:47 2026 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 869E3254841; Tue, 29 Jul 2025 10:28:39 +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=1753784919; cv=none; b=SCVmdTGhZ7dX5Wr8uruRNkCbwwHM78rKJevcQlGGMbA4QyQ6tqOKx4K6M2li7JSTexfPd9kndpJUgaff4YiNBDRuZpDO7hn4l6x8y+o7BhhtUzJ3F6/LJobQHeyuMoUQ7t2rycIXa/5RiSFu1jEFyqA7J8Hj2p+Pj/x2wkKa2sY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753784919; c=relaxed/simple; bh=PoVJYmha+F5Q+Shyh8Z6KZj91FS00Vyug/N39XeYgMM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=di9yNkO5Ja2NBSzHYqwzmrjjaNNKSeLDo/htf7gnIxzyBvbwaWAsl8kIlElSpcJde/mQQMdk7JNOXeNZCSgPPKxcgtMhPE5Ac6ingbGW2l3oaSOWcqgNgtIM6u5uBtfECGqvjGb69TYL2A7/6sLNFsFG/D0nKgpT+HQ5sJrGtwE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cvoNT2pk; 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="cvoNT2pk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33CB7C4CEEF; Tue, 29 Jul 2025 10:28:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753784919; bh=PoVJYmha+F5Q+Shyh8Z6KZj91FS00Vyug/N39XeYgMM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cvoNT2pkbNwrm9T3+/0Qy1iPrq8hPGDjfzb55rvDPU92Tp6ra268grQaNQUx/5YMG flGt4OoLgVr05TK/y0/MaDFjfeaCK9Nmax3CMWqKkBtEQsUomO5+nm4IinpJJAoxKo DiuxSJys3Fu7aNhh/s7CmnP1JP7ESYd+2zu8r4pwK+SC6W8TDAlos1TLXwn6yIJSw5 PLqtuv8SRR78GdCvlV+OXenW26soPrMNPSXYxcVCGLhK0yavus3sL3n35uoWAykTU2 3r2sseihRrqZPsOB0wjVMzNJ/ibme2TeBY6y8zW9RNF7faQPJ10WIm8FXw+7goiAEU yXy0ct+8CUksg== 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 Subject: [RFC 02/10] ftrace: Add register_ftrace_direct_hash function Date: Tue, 29 Jul 2025 12:28:05 +0200 Message-ID: <20250729102813.1531457-3-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250729102813.1531457-1-jolsa@kernel.org> References: <20250729102813.1531457-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Adding register_ftrace_direct_hash function that registers all entries (ip -> direct) provided in hash argument. The difference to current register_ftrace_direct is - hash argument that allows to register multiple ip -> direct entries at once - we can call register_ftrace_direct_hash 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 | 123 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 130 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index b672ca15f265..e45bcc9de53b 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -526,6 +526,8 @@ int unregister_ftrace_direct(struct ftrace_ops *ops, un= signed 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= ); =20 +int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash= *hash); + void ftrace_stub_direct_tramp(void); =20 #else @@ -552,6 +554,11 @@ static inline int modify_ftrace_direct_nolock(struct f= trace_ops *ops, unsigned l return -ENODEV; } =20 +int register_ftrace_direct_hash(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 5b8f565a1258..1dbb113f4e9c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6219,6 +6219,129 @@ int modify_ftrace_direct(struct ftrace_ops *ops, un= signed 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_h= ash *b) +{ + struct ftrace_func_entry *entry; + struct ftrace_hash *add; + int size, i; + + size =3D hash_count(a) + hash_count(b); + if (size > 32) + size =3D 32; + + add =3D alloc_and_copy_ftrace_hash(fls(size), a); + if (!add) + goto error; + + size =3D 1 << b->size_bits; + for (i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + if (add_hash_entry_direct(add, entry->ip, entry->direct) =3D=3D NULL) + goto error; + } + } + return add; + + error: + free_ftrace_hash(add); + return NULL; +} + +static void call_direct_funcs_hash(unsigned long ip, unsigned long pip, + struct ftrace_ops *ops, struct ftrace_regs *fregs) +{ + unsigned long addr; + + addr =3D ftrace_find_rec_direct(ip); + if (!addr) + return; + + arch_ftrace_set_direct_caller(fregs, addr); +} + +int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash= *hash) +{ + struct ftrace_hash *filter_hash =3D NULL, *new_hash =3D NULL, *free_hash = =3D NULL; + struct ftrace_func_entry *entry; + int i, size, err; + bool reg; + + if (!hash_count(hash)) + return 0; + + mutex_lock(&direct_mutex); + + /* Make sure requested entry is not already registered. */ + size =3D 1 << hash->size_bits; + for (i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + if (__ftrace_lookup_ip(direct_functions, entry->ip)) + goto out_unlock; + } + } + + filter_hash =3D ops->func_hash ? ops->func_hash->filter_hash : NULL; + + /* If there's nothing in filter_hash we need to register the ops. */ + reg =3D hash_count(filter_hash) =3D=3D 0; + if (reg) { + if (ops->func || ops->trampoline) + goto out_unlock; + if (ops->flags & FTRACE_OPS_FL_ENABLED) + goto out_unlock; + } + + filter_hash =3D hash_add(filter_hash, hash); + if (!filter_hash) + goto out_unlock; + + new_hash =3D hash_add(direct_functions, hash); + if (!new_hash) + goto out_unlock; + + free_hash =3D direct_functions; + rcu_assign_pointer(direct_functions, new_hash); + new_hash =3D NULL; + + if (reg) { + ops->func =3D call_direct_funcs_hash; + ops->flags =3D MULTI_FLAGS; + ops->trampoline =3D FTRACE_REGS_ADDR; + ops->local_hash.filter_hash =3D filter_hash; + + err =3D register_ftrace_function_nolock(ops); + if (!err) + filter_hash =3D NULL; + } else { + err =3D ftrace_update_ops(ops, filter_hash, EMPTY_HASH); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (free_hash && free_hash !=3D EMPTY_HASH) + call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb); + + if (filter_hash) + free_ftrace_hash(filter_hash); + + return err; +} +EXPORT_SYMBOL_GPL(register_ftrace_direct_hash); + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ =20 /** --=20 2.50.1