From nobody Tue Dec 2 02:04:05 2025 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 4725B30BBBA; Thu, 20 Nov 2025 21:24:54 +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=1763673895; cv=none; b=rBUSna46DJrKvvp2kJ5ZpDiA35GOKHcayAz2h/Ti1JJiMUgc5ubVvZGJa1/Lv5v6kGM2Qb4kp16P5TVdxwHYffJCnH5KmbGrg+mjBYIjsY+8N26ylYgnSODpFYdxF1VwM2QZc4FxdVIxf4xsHglu0LIQtuzp/u5WFVzPpx4NJ08= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763673895; c=relaxed/simple; bh=lfhp1WdaWfC5KnIhI8D/pxbcrNx0gUfpW6nQZKPGORs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OktYYs2X+hIPNr+UUfRr6pMPI3KA15zJOH7d40QXIaeq96fuPYuln/02tS5wvECTMYLllEI+FhmNgsAjnjpodXtm0561aNzt4yF91PbgG+uBkmrkg8jrJ72JkNrVbPvdSYLILoUpI++s+o7m3U+bFV5Z9a7lgcY3t6NBgM4NfMk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fW/jD4vJ; 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="fW/jD4vJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA1EFC4CEF1; Thu, 20 Nov 2025 21:24:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763673894; bh=lfhp1WdaWfC5KnIhI8D/pxbcrNx0gUfpW6nQZKPGORs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fW/jD4vJ8E6utvZI+At/2/HbVruCbI82EKwo7RX4iGEMwyc2fFr657vlgozhSDoUO nxAR/iXSnpgkCW9hB3BTdwN9XNVLRzx6hIuAIjadj2NK6glL/ZXixaBeunYqj7DBK9 4YWKjfiAzlHncZC7IrNgQObR6dPcdvPVJAIld6caF6wukWWQMLaCJhYgavRdzt1fbp ltMZd3h4XUfu/N0/UX1ZQcnGMHvZlYReP30izOvg/2DaEO0QswJy0sE2A3d9ZommN+ ZyTN+Kc0jkOEcF86BWnNnuToWjHkXfxB6hy3HLFY50BR9bG2Os2gghjl6aD7xlcmbH ZUTsMxohPgyAw== 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: [PATCHv3 bpf-next 4/8] ftrace: Add update_ftrace_direct_del function Date: Thu, 20 Nov 2025 22:23:58 +0100 Message-ID: <20251120212402.466524-5-jolsa@kernel.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251120212402.466524-1-jolsa@kernel.org> References: <20251120212402.466524-1-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 update_ftrace_direct_del function that removes all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current unregister_ftrace_direct is - hash argument that allows to unregister multiple ip -> direct entries at once - we can call update_ftrace_direct_del multiple times on the same ftrace_ops object, becase we do not need to unregister all entries at once, we can do it gradualy with the help of ftrace_update_ops function 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 | 6 +++ kernel/trace/ftrace.c | 110 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 116 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 9cf4cd56d982..c571deeff840 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -551,6 +551,7 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsign= ed long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr= ); =20 int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *h= ash); +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *h= ash); =20 void ftrace_stub_direct_tramp(void); =20 @@ -583,6 +584,11 @@ static inline int update_ftrace_direct_add(struct ftra= ce_ops *ops, struct ftrace return -ENODEV; } =20 +static inline int update_ftrace_direct_del(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 850ff55ff25e..cc730a8fd087 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6376,6 +6376,116 @@ int update_ftrace_direct_add(struct ftrace_ops *ops= , struct ftrace_hash *hash) return err; } =20 +/** + * hash_sub - substracts @b from @a 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_sub(struct ftrace_hash *a, struct ftrace_h= ash *b) +{ + struct ftrace_func_entry *entry, *del; + struct ftrace_hash *sub; + int size, i; + + sub =3D alloc_and_copy_ftrace_hash(a->size_bits, a); + if (!sub) + goto error; + + size =3D 1 << b->size_bits; + for (i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + del =3D __ftrace_lookup_ip(sub, entry->ip); + if (WARN_ON_ONCE(!del)) + goto error; + remove_hash_entry(sub, del); + kfree(del); + } + } + return sub; + + error: + free_ftrace_hash(sub); + return NULL; +} + +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *h= ash) +{ + struct ftrace_hash *old_direct_functions =3D NULL, *new_direct_functions = =3D NULL; + struct ftrace_hash *old_filter_hash =3D NULL, *new_filter_hash =3D NULL; + struct ftrace_func_entry *del, *entry; + unsigned long size, i; + int err =3D -EINVAL; + + if (!hash_count(hash)) + return -EINVAL; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions =3D=3D EMPTY_HASH) + return -EINVAL; + + mutex_lock(&direct_mutex); + + old_filter_hash =3D ops->func_hash ? ops->func_hash->filter_hash : NULL; + old_direct_functions =3D direct_functions; + + /* Make sure requested entries are already registered. */ + size =3D 1 << hash->size_bits; + for (i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + del =3D __ftrace_lookup_ip(direct_functions, entry->ip); + if (!del || del->direct !=3D entry->direct) + goto out_unlock; + } + } + + err =3D -ENOMEM; + new_filter_hash =3D hash_sub(old_filter_hash, hash); + if (!new_filter_hash) + goto out_unlock; + + new_direct_functions =3D hash_sub(old_direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + /* If there's nothing left, we need to unregister the ops. */ + if (ftrace_hash_empty(new_filter_hash)) { + err =3D unregister_ftrace_function(ops); + if (!err) { + /* cleanup for possible another register call */ + ops->func =3D NULL; + ops->trampoline =3D 0; + ftrace_free_filter(ops); + ops->func_hash->filter_hash =3D NULL; + } + } else { + err =3D 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 + */ + } + + if (err) { + /* reset direct_functions and free the new one */ + old_direct_functions =3D new_direct_functions; + } else { + rcu_assign_pointer(direct_functions, new_direct_functions); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (old_direct_functions && old_direct_functions !=3D 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 */ =20 /** --=20 2.51.1