From patchwork Tue Oct 5 08:26:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Ambardar X-Patchwork-Id: 12535837 X-Patchwork-Delegate: bpf@iogearbox.net 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 572F5C433EF for ; Tue, 5 Oct 2021 08:31:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FFDD61056 for ; Tue, 5 Oct 2021 08:31:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232954AbhJEIdo (ORCPT ); Tue, 5 Oct 2021 04:33:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233460AbhJEIdj (ORCPT ); Tue, 5 Oct 2021 04:33:39 -0400 Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A660C061755; Tue, 5 Oct 2021 01:31:49 -0700 (PDT) Received: by mail-pg1-x533.google.com with SMTP id q201so6452085pgq.12; Tue, 05 Oct 2021 01:31:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=6XuRo9+dsLwMOEdoGhGnTKjYpBra+3KZ9lusvAfMqso=; b=TGpO7+Hsx23ekJIj0k//9H6Ms7oIBOKCV7BNtfOSpzZ3fgi7kZgQ4unSXlfxuSpP1K A87CBuOguCjsaSt7k7CXc/T2yrsT2uwM/RBeRdl2kbjuYEGrvwLXskyL+vHaS/YKDKFM Iql5sBSPCXZ4f4+AYkSbgJ82a6/HUS20Nd6r8B0p2o4+J52aEW6lSxKKoa8k3CjQWkhY 1bvfTciU7O+wwbYX/I7BSBCcfG8VNuhuSxZyobFtpYHDszSzmITqP16lDFqopmzXhlPk klyKaoVcRXtAhNdi4OUA6R39srOLsiBaTUjBbpUxc08MuOtxvHngcrYHz3Jcb7qt/8Dz DVUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=6XuRo9+dsLwMOEdoGhGnTKjYpBra+3KZ9lusvAfMqso=; b=RJplqjCsY9VXglpzdKpHVEOaKWOVuwxNo/MwEApMaVyuJo1zDkJeu6iQEBfm8u5E2G z4HuNzC3zCLtIVZaWEoL284lBq09Kk/GMYLAkgP1Q5nwagyLWZWw6xnxSxlROICU/sOL 8UWhDaCcz5XD5dRdPLuyZGg9fEl3YEYr2yMyCHXioGeB/T3mSyesgdbMIWx0rdKnY/RS zKeZL11Bzhy939UjK2CyEWygfk8ktS3Z8hJ8vn94uEKwFADWgQBa6sZ8ob3pxllWgdwl C7tWlduOaZ8vlfJszdEBLTgaOZX6oLu0GPJ7pJs/g6YUj+hVb8auLP38EEPUk6Rrb+xi jcRQ== X-Gm-Message-State: AOAM532KbXbcvuD1Ylu7VVk8Wmi6HeMOXZ/VGN78qByX/H6jfmB5CkQM BmiJvFfuoyGjTJeY7VW1Nmc= X-Google-Smtp-Source: ABdhPJyLhqxZxibIepJ0YDGhNBSgdPWdkxN8oH95W/evrMgLubNxfcHaUIUoUPFOSQ7ymi8quwwpnQ== X-Received: by 2002:a63:7543:: with SMTP id f3mr14725608pgn.449.1633422709011; Tue, 05 Oct 2021 01:31:49 -0700 (PDT) Received: from localhost.localdomain ([2001:470:e92d:10:78ba:4bcc:a59a:2284]) by smtp.gmail.com with ESMTPSA id a15sm4941257pfg.53.2021.10.05.01.31.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Oct 2021 01:31:48 -0700 (PDT) From: Tony Ambardar X-Google-Original-From: Tony Ambardar To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Thomas Bogendoerfer , Paul Burton Cc: Tony Ambardar , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-mips@vger.kernel.org, Johan Almbladh , Tiezhu Yang , Hassan Naveed , David Daney , Luke Nelson , Serge Semin , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh Subject: [RFC PATCH bpf-next v2 11/16] bpf: allow tailcalls in subprograms for MIPS64/MIPS32 Date: Tue, 5 Oct 2021 01:26:55 -0700 Message-Id: <77dfea2d224e7545e5e4d3f350721d27e5a77b0d.1633392335.git.Tony.Ambardar@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC 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, and also enable the feature for the MIPS64/MIPS32 JIT. Signed-off-by: Tony Ambardar --- arch/mips/net/ebpf_jit.c | 6 ++++++ arch/x86/net/bpf_jit_comp.c | 6 ++++++ include/linux/filter.h | 1 + kernel/bpf/core.c | 6 ++++++ kernel/bpf/verifier.c | 3 ++- 5 files changed, 21 insertions(+), 1 deletion(-) diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c index 7d8ed8bb19ab..501c1d532be6 100644 --- a/arch/mips/net/ebpf_jit.c +++ b/arch/mips/net/ebpf_jit.c @@ -2416,3 +2416,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) bpf_jit_binary_free(header); goto out_ctx; } + +/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */ +bool bpf_jit_supports_subprog_tailcalls(void) +{ + return true; +} diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 3ae729bb2475..2d78588fb5b5 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2367,3 +2367,9 @@ bool bpf_jit_supports_kfunc_call(void) { return true; } + +/* 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 16e5cebea82c..50b50fb271b5 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -933,6 +933,7 @@ 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 189934d2a3f2..c82b48ed0005 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2366,6 +2366,12 @@ 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 6e2ebcb0d66f..267de5428fad 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5144,7 +5144,8 @@ 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,