From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 69-171-232-181.mail-mxout.facebook.com (69-171-232-181.mail-mxout.facebook.com [69.171.232.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2D2B346791 for ; Thu, 7 May 2026 21:30:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=69.171.232.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778189455; cv=none; b=JHIwVYkardCxiwmjcQqVC4JfX+oiLgVeeLFjT72/cq+9BC75+rCRoEEqKZNL9M8uODXlMdyMIKgho+FVW2TM9eWYlOX2bc+47VqymhMHPQs6cP9dE0RexYpmq4gPajsOALccCL+pbyG/Op7q0gvazEUlcjP7NYbgza5jMFMys5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778189455; c=relaxed/simple; bh=Jqlu9UdVuuIIOu0y8iaGcJJWRbLLrm7D33Tv5XHBQTo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CfXO3iBtW4zBzB2DV4OUbRKmJ4BTOqJ+6mmWI0VoLWyCqJo4p5rj8Vu+f2GCa79pMt+wKgKVsL0EOFbYWDqtb2aSf7vAHvG+c1eqcJHo9i48zYHQCLCH7h/Emro4lTNXUHn3fYCabFDoQY4W5LHOcPS3gs0KAmYPeGgOwr40Lyw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev; spf=fail smtp.mailfrom=linux.dev; arc=none smtp.client-ip=69.171.232.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devvm16039.vll0.facebook.com (Postfix, from userid 128203) id 65E3892BAA4E9; Thu, 7 May 2026 14:30:39 -0700 (PDT) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , "Jose E . Marchesi" , kernel-team@fb.com, Martin KaFai Lau , Puranjay Mohan Subject: [PATCH bpf-next v2 11/23] bpf: Prepare architecture JIT support for stack arguments Date: Thu, 7 May 2026 14:30:39 -0700 Message-ID: <20260507213039.1130658-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260507212942.1122000-1-yonghong.song@linux.dev> References: <20260507212942.1122000-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Add bpf_jit_supports_stack_args() as a weak function defaulting to false. Architectures that implement JIT support for stack arguments override it to return true. Reject BPF functions with more than 5 parameters at verification time if the architecture does not support stack arguments. Acked-by: Puranjay Mohan Signed-off-by: Yonghong Song --- include/linux/filter.h | 1 + kernel/bpf/btf.c | 8 +++++++- kernel/bpf/core.c | 5 +++++ 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 918d9b34eac6..a515a9769078 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1184,6 +1184,7 @@ bool bpf_jit_inlines_helper_call(s32 imm); bool bpf_jit_supports_subprog_tailcalls(void); bool bpf_jit_supports_percpu_insn(void); bool bpf_jit_supports_kfunc_call(void); +bool bpf_jit_supports_stack_args(void); bool bpf_jit_supports_far_kfunc_call(void); bool bpf_jit_supports_exceptions(void); bool bpf_jit_supports_ptr_xchg(void); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index ec3fb8c8f4ee..bf83b737d55c 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -7886,8 +7886,14 @@ int btf_prepare_func_args(struct bpf_verifier_env = *env, int subprog) MAX_BPF_FUNC_ARGS, tname, nargs); return -EFAULT; } - if (nargs > MAX_BPF_FUNC_REG_ARGS) + if (nargs > MAX_BPF_FUNC_REG_ARGS) { + if (!bpf_jit_supports_stack_args()) { + bpf_log(log, "JIT does not support function %s() with %d args\n", + tname, nargs); + return -ENOTSUPP; + } sub->stack_arg_cnt =3D nargs - MAX_BPF_FUNC_REG_ARGS; + } =20 if (is_global && nargs > MAX_BPF_FUNC_REG_ARGS) { bpf_log(log, "global function %s has %d > %d args, stack args not supp= orted\n", diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 6f94b0ef3659..5d8932f5fb38 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -3217,6 +3217,11 @@ bool __weak bpf_jit_supports_kfunc_call(void) return false; } =20 +bool __weak bpf_jit_supports_stack_args(void) +{ + return false; +} + bool __weak bpf_jit_supports_far_kfunc_call(void) { return false; --=20 2.53.0-Meta