From nobody Thu Oct 2 03:22:19 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 5B16730E82D; Tue, 23 Sep 2025 21:53:35 +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=1758664415; cv=none; b=lZuGaznuT9v70/McuBHi0NymrMz+0XtQK+ajskw4KHvhSWHqM6DwZ2/EJm3NrI2/qgg6fhNruopIYlgDSbA+vI7hOle8YpYxDiLXJjzPdtQc3ecwUuY6bCkYO9Ks+jyY/2g8pV3RZvRgg9xTmdmGGpoB4rluNkzEGdROOVNF32Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758664415; c=relaxed/simple; bh=43T9HLopp5TSSfaS/PpEBs04jnF5DnlAwLGcj6tvQ8M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bw5+c6M+t4iZhi6yWxSPk3N2z0WQrWxZpSDK9RTxAT/Uwcr4njGdqmOtpZBOUO1C7US5SNvjpybfacuxHbrygVoYVu3L+9cavlZFdFeW1NunwfS6sX036IBtB/G60SkG/UzDw+eRtG2n7xkONMKnQxlNCsn1AgTPM7HB6oIdHYY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QFtdiphn; 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="QFtdiphn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D072C4CEF5; Tue, 23 Sep 2025 21:53:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758664415; bh=43T9HLopp5TSSfaS/PpEBs04jnF5DnlAwLGcj6tvQ8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QFtdiphnN9U6PqfI4yB+FMCirtdRv+x4abZHcBByKq62QTC45K2gDopib2ulQNxDb w+HUWaDby+yb+VNyzwN+0gQrESBnT43VpPMATSYgc1DbjLs7r+YgDnxeIg0K8xfDdv pE5yM0R/CrUBYjye8s/9oNBEKYKWFdpsVUbaLuyWDfI3Tlq7DFt8sEn1o3fjG0psp3 gflVn+TR38Tu5VPU5U+AwKXvQgdmNeUpOpFhr6Sc+Rz8+LNVSSSN/pI76pqzXROjDb YnuZUIIpmZMN4HAXlMmYj5gleREbbO7ujyhVDrMCjLTHukL9FRbMD9Y4w+gEWW5a/q kqq2AXN8Lgi5w== 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: [PATCH 9/9] bpf, x86: Use single ftrace_ops for direct calls Date: Tue, 23 Sep 2025 23:51:47 +0200 Message-ID: <20250923215147.1571952-10-jolsa@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250923215147.1571952-1-jolsa@kernel.org> References: <20250923215147.1571952-1-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" Using single ftrace_ops for direct calls update instead of allocating ftrace_ops obejct for each trampoline. At the moment we can enable this only on x86 arch, because arm relies on ftrace_ops object representing just single trampoline image (stored in ftrace_ops::direct_call). Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on each arch that supports this. Signed-off-by: Jiri Olsa --- arch/x86/Kconfig | 1 + kernel/bpf/trampoline.c | 85 +++++++++++++++++++++++++++++++++++------ kernel/trace/Kconfig | 3 ++ kernel/trace/ftrace.c | 15 +++++++- 4 files changed, 92 insertions(+), 12 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 52c8910ba2ef..bfc9115baa6f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -330,6 +330,7 @@ config X86 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE select ARCH_SUPPORTS_PT_RECLAIM if X86_64 + select HAVE_SINGLE_FTRACE_DIRECT_OPS if X86_64 && DYNAMIC_FTRACE_WITH_DIR= ECT_CALLS =20 config INSTRUCTION_DECODER def_bool y diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 3464859189a2..e3b721773dfb 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -33,12 +33,40 @@ static DEFINE_MUTEX(trampoline_mutex); #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_dire= ct_mutex); =20 +#ifdef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS +static struct bpf_trampoline *direct_ops_ip_lookup(struct ftrace_ops *ops,= unsigned long ip) +{ + struct hlist_head *head_ip; + struct bpf_trampoline *tr; + + mutex_lock(&trampoline_mutex); + head_ip =3D &trampoline_ip_table[hash_64(ip, TRAMPOLINE_HASH_BITS)]; + hlist_for_each_entry(tr, head_ip, hlist_ip) { + if (tr->func.addr =3D=3D (void *) ip) + goto out; + } + tr =3D NULL; +out: + mutex_unlock(&trampoline_mutex); + return tr; +} +#else +static struct bpf_trampoline *direct_ops_ip_lookup(struct ftrace_ops *ops,= unsigned long ip) +{ + return ops->private; +} +#endif /* CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS */ + static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, unsigned long= ip, enum ftrace_ops_cmd cmd) { - struct bpf_trampoline *tr =3D ops->private; + struct bpf_trampoline *tr; int ret =3D 0; =20 + tr =3D direct_ops_ip_lookup(ops, ip); + if (!tr) + return -EINVAL; + if (cmd =3D=3D FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF) { /* This is called inside register_ftrace_direct_multi(), so * tr->mutex is already locked. @@ -137,6 +165,48 @@ void bpf_image_ksym_del(struct bpf_ksym *ksym) PAGE_SIZE, true, ksym->name); } =20 +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +#ifdef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS +struct ftrace_ops direct_ops =3D { + .ops_func =3D bpf_tramp_ftrace_ops_func, +}; + +static int direct_ops_get(struct bpf_trampoline *tr) +{ + tr->fops =3D &direct_ops; + return 0; +} +static void direct_ops_clear(struct bpf_trampoline *tr) { } +static void direct_ops_free(struct bpf_trampoline *tr) { } +#else +static int direct_ops_get(struct bpf_trampoline *tr) +{ + tr->fops =3D kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL); + if (!tr->fops) + return -1; + tr->fops->private =3D tr; + tr->fops->ops_func =3D bpf_tramp_ftrace_ops_func; + return 0; +} + +static void direct_ops_clear(struct bpf_trampoline *tr) +{ + tr->fops->func =3D NULL; + tr->fops->trampoline =3D 0; +} + +static void direct_ops_free(struct bpf_trampoline *tr) +{ + if (tr->fops) { + ftrace_free_filter(tr->fops); + kfree(tr->fops); + } +} +#endif /* CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS */ +#else +static void direct_ops_free(struct bpf_trampoline *tr) { } +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + static struct bpf_trampoline *bpf_trampoline_lookup(u64 key, unsigned long= ip) { struct bpf_trampoline *tr; @@ -155,14 +225,11 @@ static struct bpf_trampoline *bpf_trampoline_lookup(u= 64 key, unsigned long ip) if (!tr) goto out; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS - tr->fops =3D kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL); - if (!tr->fops) { + if (direct_ops_get(tr)) { kfree(tr); tr =3D NULL; goto out; } - tr->fops->private =3D tr; - tr->fops->ops_func =3D bpf_tramp_ftrace_ops_func; #endif =20 tr->key =3D key; @@ -482,8 +549,7 @@ static int bpf_trampoline_update(struct bpf_trampoline = *tr, bool lock_direct_mut * trampoline again, and retry register. */ /* reset fops->func and fops->trampoline for re-register */ - tr->fops->func =3D NULL; - tr->fops->trampoline =3D 0; + direct_ops_clear(tr); =20 /* free im memory and reallocate later */ bpf_tramp_image_free(im); @@ -864,10 +930,7 @@ void bpf_trampoline_put(struct bpf_trampoline *tr) */ hlist_del(&tr->hlist_key); hlist_del(&tr->hlist_ip); - if (tr->fops) { - ftrace_free_filter(tr->fops); - kfree(tr->fops); - } + direct_ops_free(tr); kfree(tr); out: mutex_unlock(&trampoline_mutex); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d2c79da81e4f..4bf5beb04a5b 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -50,6 +50,9 @@ config HAVE_DYNAMIC_FTRACE_WITH_REGS config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS bool =20 +config HAVE_SINGLE_FTRACE_DIRECT_OPS + bool + config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS bool =20 diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2af1304d1a83..c4b969fb1010 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2592,8 +2592,13 @@ unsigned long ftrace_find_rec_direct(unsigned long i= p) static void call_direct_funcs(unsigned long ip, unsigned long pip, struct ftrace_ops *ops, struct ftrace_regs *fregs) { - unsigned long addr =3D READ_ONCE(ops->direct_call); + unsigned long addr; =20 +#ifdef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS + addr =3D ftrace_find_rec_direct(ip); +#else + addr =3D READ_ONCE(ops->direct_call); +#endif if (!addr) return; =20 @@ -5986,6 +5991,10 @@ int register_ftrace_direct(struct ftrace_ops *ops, u= nsigned long ip, unsigned lo if (!hash) return -ENOMEM; =20 +#ifndef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS + ops->direct_call =3D addr; +#endif + err =3D register_ftrace_direct_hash(ops, hash); free_ftrace_hash(hash); return err; @@ -6050,6 +6059,10 @@ int modify_ftrace_direct(struct ftrace_ops *ops, uns= igned long ip, unsigned long return -ENOMEM; =20 err =3D modify_ftrace_direct_hash(ops, hash, lock_direct_mutex); +#ifndef CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS + if (!err) + ops->direct_call =3D addr; +#endif free_ftrace_hash(hash); return err; } --=20 2.51.0