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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9F56BC433EF for ; Thu, 26 May 2022 14:48:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=x7bqAXBkT3WjzDoNSm4VfSVz46/HvSoFQV9CVEKCcGA=; b=ngwbB9iPNVao2K vjyO2HIvdrtlcIh2uLIvGw6CO/f4AVvVhtXyrhGMqzXs9/YCk2YR/cAYt90NY/UlmRSdj9LISK50D bA+viq5abAdGCAEFmwGMVg/Klj+tTJ0qX4X/vX2InCl+I0sS6mKSvlMsMNiSVkWuT8O0TOj/r31aU E+O5+F3zU4E6Pua4QNcbv0SRukeEbe92drVFdsJLzHccQ63FLbu5swy6SfX7dFKCXMfYL0fynuAbr qfKOVZWvehauE0HKvr+cuzFlxrgC5/lLnIGLm6fx+Bk0Wmbe+2kXBm1yxENgou/8UML11GF/LokTA 2ky5T0GeDECDHVaDCLrw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nuEla-00FCps-4Z; Thu, 26 May 2022 14:47:10 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nuElN-00FCh9-2D for linux-arm-kernel@lists.infradead.org; Thu, 26 May 2022 14:47:04 +0000 Received: from kwepemi500013.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4L89jR5tlczjX4P; Thu, 26 May 2022 22:46:03 +0800 (CST) Received: from [10.67.111.192] (10.67.111.192) by kwepemi500013.china.huawei.com (7.221.188.120) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 26 May 2022 22:46:46 +0800 Message-ID: <3768a958-6d20-cd0e-ce4b-01998682d513@huawei.com> Date: Thu, 26 May 2022 22:46:46 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH bpf-next v5 3/6] bpf: Remove is_valid_bpf_tramp_flags() Content-Language: en-US To: Mark Rutland CC: , , , , , Catalin Marinas , Will Deacon , Steven Rostedt , Ingo Molnar , Daniel Borkmann , Alexei Starovoitov , Zi Shen Lim , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , "David S . Miller" , Hideaki YOSHIFUJI , David Ahern , Thomas Gleixner , Borislav Petkov , Dave Hansen , , , Shuah Khan , Jakub Kicinski , Jesper Dangaard Brouer , Pasha Tatashin , Ard Biesheuvel , Daniel Kiss , Steven Price , Sudeep Holla , Marc Zyngier , Peter Collingbourne , Mark Brown , Delyan Kratunov , Kumar Kartikeya Dwivedi References: <20220518131638.3401509-1-xukuohai@huawei.com> <20220518131638.3401509-4-xukuohai@huawei.com> <985fe022-552c-9d04-16d8-14784c4075f8@huawei.com> From: Xu Kuohai In-Reply-To: X-Originating-IP: [10.67.111.192] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemi500013.china.huawei.com (7.221.188.120) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220526_074657_627759_A0AE87E0 X-CRM114-Status: GOOD ( 19.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 5/26/2022 6:12 PM, Mark Rutland wrote: > On Thu, May 26, 2022 at 05:45:25PM +0800, Xu Kuohai wrote: >> On 5/25/2022 9:45 PM, Mark Rutland wrote: >>> On Wed, May 18, 2022 at 09:16:35AM -0400, Xu Kuohai wrote: >>>> BPF_TRAM_F_XXX flags are not used by user code and are almost constant >>>> at compile time, so run time validation is a bit overkill. Remove >>>> is_valid_bpf_tramp_flags() and add some usage comments. >>>> >>>> Signed-off-by: Xu Kuohai >>>> Acked-by: Song Liu >>> >>> Am I right in thinking this is independent of the arm64-specific bits, and >>> could be taken on its own now? >>> >> >> Currenly is_valid_bpf_tramp_flags() is defined in x86 and called before >> bpf trampoline is constructed. The check logic is irrelevant to the >> architecture code. So we also need to call this function on arm64. But >> as Alexei pointed out, the check is not requried, so it's better to >> remove it before adding bpf trampoline to arm64. > > Cool. So this patch could be merged now, even if the rest of the series needs > more work? > Agree with you, thanks. > Thanks, > Mark. > >>>> --- >>>> arch/x86/net/bpf_jit_comp.c | 20 -------------------- >>>> kernel/bpf/bpf_struct_ops.c | 3 +++ >>>> kernel/bpf/trampoline.c | 3 +++ >>>> 3 files changed, 6 insertions(+), 20 deletions(-) >>>> >>>> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c >>>> index a2b6d197c226..7698ef3b4821 100644 >>>> --- a/arch/x86/net/bpf_jit_comp.c >>>> +++ b/arch/x86/net/bpf_jit_comp.c >>>> @@ -1922,23 +1922,6 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog, >>>> return 0; >>>> } >>>> >>>> -static bool is_valid_bpf_tramp_flags(unsigned int flags) >>>> -{ >>>> - if ((flags & BPF_TRAMP_F_RESTORE_REGS) && >>>> - (flags & BPF_TRAMP_F_SKIP_FRAME)) >>>> - return false; >>>> - >>>> - /* >>>> - * BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops, >>>> - * and it must be used alone. >>>> - */ >>>> - if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) && >>>> - (flags & ~BPF_TRAMP_F_RET_FENTRY_RET)) >>>> - return false; >>>> - >>>> - return true; >>>> -} >>>> - >>>> /* Example: >>>> * __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev); >>>> * its 'struct btf_func_model' will be nr_args=2 >>>> @@ -2017,9 +2000,6 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i >>>> if (nr_args > 6) >>>> return -ENOTSUPP; >>>> >>>> - if (!is_valid_bpf_tramp_flags(flags)) >>>> - return -EINVAL; >>>> - >>>> /* Generated trampoline stack layout: >>>> * >>>> * RBP + 8 [ return address ] >>>> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c >>>> index d9a3c9207240..0572cc5aeb28 100644 >>>> --- a/kernel/bpf/bpf_struct_ops.c >>>> +++ b/kernel/bpf/bpf_struct_ops.c >>>> @@ -341,6 +341,9 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, >>>> >>>> tlinks[BPF_TRAMP_FENTRY].links[0] = link; >>>> tlinks[BPF_TRAMP_FENTRY].nr_links = 1; >>>> + /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops, >>>> + * and it must be used alone. >>>> + */ >>>> flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0; >>>> return arch_prepare_bpf_trampoline(NULL, image, image_end, >>>> model, flags, tlinks, NULL); >>>> diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c >>>> index 93c7675f0c9e..bd3f2e673874 100644 >>>> --- a/kernel/bpf/trampoline.c >>>> +++ b/kernel/bpf/trampoline.c >>>> @@ -358,6 +358,9 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr) >>>> >>>> if (tlinks[BPF_TRAMP_FEXIT].nr_links || >>>> tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links) >>>> + /* NOTE: BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME >>>> + * should not be set together. >>>> + */ >>>> flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME; >>>> >>>> if (ip_arg) >>>> -- >>>> 2.30.2 >>>> >>> . >> > . _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel