From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6945EC00140 for ; Mon, 15 Aug 2022 21:15:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233387AbiHOVP1 (ORCPT ); Mon, 15 Aug 2022 17:15:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347994AbiHOVHy (ORCPT ); Mon, 15 Aug 2022 17:07:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45BA62E681; Mon, 15 Aug 2022 12:17:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D6D916009B; Mon, 15 Aug 2022 19:17:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFF7CC433D6; Mon, 15 Aug 2022 19:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660591049; bh=fNf3lYZ3JXkcpaPS13aW1IHh+HAR/gsUqnLFHXNzqIs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dsYmP9qZ30Y+vXmrFaa0rijYfoDFkIwMrykdWafwixhu77pjjMh6zOCcYtswR7vX7 zmoxpW1FlWCrX6qKw5/bBQzgIu+Tr493ZiHtoQ88CIfHm4THAt4ycd6MlV1CTbAv9c wNrX1qNMUsDizOYiL8ti3vzB5lkyg8N3Kb90Z8Kk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tony Ambardar , Jakub Sitnicki , Daniel Borkmann , Sasha Levin Subject: [PATCH 5.18 0455/1095] bpf, x64: Add predicate for bpf2bpf with tailcalls support in JIT Date: Mon, 15 Aug 2022 19:57:34 +0200 Message-Id: <20220815180448.447796708@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180429.240518113@linuxfoundation.org> References: <20220815180429.240518113@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tony Ambardar [ Upstream commit 95acd8817e66d031d2e6ee7def3f1e1874819317 ] The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail calls for only x86-64. Change the logic to instead rely on a new weak function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable JIT backend can override. Update the x86-64 eBPF JIT to reflect this. Signed-off-by: Tony Ambardar [jakub: drop MIPS bits and tweak patch subject] Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com Signed-off-by: Sasha Levin --- arch/x86/net/bpf_jit_comp.c | 6 ++++++ include/linux/filter.h | 1 + kernel/bpf/core.c | 6 ++++++ kernel/bpf/verifier.c | 3 ++- 4 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 9ec96d5a8239..124456bb23b9 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2477,3 +2477,9 @@ void *bpf_arch_text_copy(void *dst, void *src, size_t len) return ERR_PTR(-EINVAL); return dst; } + +/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */ +bool bpf_jit_supports_subprog_tailcalls(void) +{ + return true; +} diff --git a/include/linux/filter.h b/include/linux/filter.h index ed0c0ff42ad5..d9a0db845b50 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -948,6 +948,7 @@ u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog); void bpf_jit_compile(struct bpf_prog *prog); bool bpf_jit_needs_zext(void); +bool bpf_jit_supports_subprog_tailcalls(void); bool bpf_jit_supports_kfunc_call(void); bool bpf_helper_changes_pkt_data(void *func); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3adff3831c04..7a1ce697689b 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2712,6 +2712,12 @@ bool __weak bpf_jit_needs_zext(void) return false; } +/* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ +bool __weak bpf_jit_supports_subprog_tailcalls(void) +{ + return false; +} + bool __weak bpf_jit_supports_kfunc_call(void) { return false; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d04147a5efa5..a6d3a8972355 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5696,7 +5696,8 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env) { - return env->prog->jit_requested && IS_ENABLED(CONFIG_X86_64); + return env->prog->jit_requested && + bpf_jit_supports_subprog_tailcalls(); } static int check_map_func_compatibility(struct bpf_verifier_env *env, -- 2.35.1