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 E56A3C433EF for ; Wed, 11 May 2022 03:19:21 +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=AtMC9DdNcW2/K0/6CKUXpSu5R/VvDUqSuqB8Srx5Ang=; b=ueVzM98KbEatDO eAGBNpGoT67o1XlGOCt8KUYAgjkToezNj9RiCUut04O7iwF3S1eyETXX/14i/JN4SdMnR7bg2FUUO /AxH+iEe51avgzpccFmhFkxalJDxYY3i6eKlmBFYmLpYfrC9yUMkWlRXRh4zSQE4RWULrEWZgyP9h tJC2eyJMyjzTNjCYevl3OKVZg/PTNCqDeiyj7uh60Us2K5Y12fABHoE4WKrQK5GkiHAc6fPkU3bh+ hOXmoBVzMUz1I7Xap2M0UXFrOqlg+88q/rCK+pYh4+QtKQDvaStW7Jc+eXjRAKrDXTJjFBqEbhWIh sKfW5Gtz/pBzYcMo69GQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nocri-004yIO-7n; Wed, 11 May 2022 03:18:18 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nocre-004yHl-Aa for linux-arm-kernel@lists.infradead.org; Wed, 11 May 2022 03:18:16 +0000 Received: from kwepemi500013.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Kyg7w6SPZzhZ4Q; Wed, 11 May 2022 11:17:32 +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; Wed, 11 May 2022 11:18:10 +0800 Message-ID: Date: Wed, 11 May 2022 11:18:09 +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 v3 4/7] bpf, arm64: Impelment bpf_arch_text_poke() for arm64 Content-Language: en-US To: Jakub Sitnicki 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 , Mark Rutland , Pasha Tatashin , Ard Biesheuvel , Daniel Kiss , Steven Price , Sudeep Holla , Marc Zyngier , Peter Collingbourne , Mark Brown , Delyan Kratunov , Kumar Kartikeya Dwivedi References: <20220424154028.1698685-1-xukuohai@huawei.com> <20220424154028.1698685-5-xukuohai@huawei.com> <87ee11obih.fsf@cloudflare.com> From: Xu Kuohai In-Reply-To: <87ee11obih.fsf@cloudflare.com> X-Originating-IP: [10.67.111.192] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) 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-20220510_201814_756388_99787546 X-CRM114-Status: GOOD ( 15.49 ) 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 5/10/2022 7:45 PM, Jakub Sitnicki wrote: > On Sun, Apr 24, 2022 at 11:40 AM -04, Xu Kuohai wrote: >> Impelment bpf_arch_text_poke() for arm64, so bpf trampoline code can use >> it to replace nop with jump, or replace jump with nop. >> >> Signed-off-by: Xu Kuohai >> Acked-by: Song Liu >> --- >> arch/arm64/net/bpf_jit_comp.c | 63 +++++++++++++++++++++++++++++++++++ >> 1 file changed, 63 insertions(+) >> >> diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c >> index 8ab4035dea27..3f9bdfec54c4 100644 >> --- a/arch/arm64/net/bpf_jit_comp.c >> +++ b/arch/arm64/net/bpf_jit_comp.c >> @@ -9,6 +9,7 @@ >> >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -18,6 +19,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #include "bpf_jit.h" >> @@ -1529,3 +1531,64 @@ void bpf_jit_free_exec(void *addr) >> { >> return vfree(addr); >> } >> + >> +static int gen_branch_or_nop(enum aarch64_insn_branch_type type, void *ip, >> + void *addr, u32 *insn) >> +{ >> + if (!addr) >> + *insn = aarch64_insn_gen_nop(); >> + else >> + *insn = aarch64_insn_gen_branch_imm((unsigned long)ip, >> + (unsigned long)addr, >> + type); >> + >> + return *insn != AARCH64_BREAK_FAULT ? 0 : -EFAULT; >> +} >> + >> +int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, >> + void *old_addr, void *new_addr) >> +{ >> + int ret; >> + u32 old_insn; >> + u32 new_insn; >> + u32 replaced; >> + enum aarch64_insn_branch_type branch_type; >> + >> + if (!is_bpf_text_address((long)ip)) >> + /* Only poking bpf text is supported. Since kernel function >> + * entry is set up by ftrace, we reply on ftrace to poke kernel >> + * functions. For kernel funcitons, bpf_arch_text_poke() is only > > Nit: s/funcitons/functions/ > >> + * called after a failed poke with ftrace. In this case, there >> + * is probably something wrong with fentry, so there is nothing >> + * we can do here. See register_fentry, unregister_fentry and >> + * modify_fentry for details. >> + */ >> + return -EINVAL; >> + >> + if (poke_type == BPF_MOD_CALL) >> + branch_type = AARCH64_INSN_BRANCH_LINK; >> + else >> + branch_type = AARCH64_INSN_BRANCH_NOLINK; >> + >> + if (gen_branch_or_nop(branch_type, ip, old_addr, &old_insn) < 0) >> + return -EFAULT; >> + >> + if (gen_branch_or_nop(branch_type, ip, new_addr, &new_insn) < 0) >> + return -EFAULT; >> + >> + mutex_lock(&text_mutex); >> + if (aarch64_insn_read(ip, &replaced)) { >> + ret = -EFAULT; >> + goto out; >> + } >> + >> + if (replaced != old_insn) { >> + ret = -EFAULT; >> + goto out; >> + } >> + >> + ret = aarch64_insn_patch_text_nosync((void *)ip, new_insn); > > Nit: No need for the explicit cast to void *. Type already matches. > >> +out: >> + mutex_unlock(&text_mutex); >> + return ret; >> +} > > . will fix in v4, thanks! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel