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 E187DC3DA7A for ; Mon, 2 Jan 2023 18:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229976AbjABSEL (ORCPT ); Mon, 2 Jan 2023 13:04:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232873AbjABSEH (ORCPT ); Mon, 2 Jan 2023 13:04:07 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8F12BF6D for ; Mon, 2 Jan 2023 10:04:05 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 13F47B80D0B for ; Mon, 2 Jan 2023 18:04:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7792BC433EF; Mon, 2 Jan 2023 18:04:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1672682642; bh=ifUmvfCBh29zQ+7sIS0FtN5zIwsm2GSxNWtY9yy8c4o=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=CWlZVqjHHqwr8igQKlHq+PKv2KHgcqIsxp0z/xZHqVoCFIOsyD9SMDKk8ri94/+4E DeX13VcOX6va985fIXJ90DjcQM0/aTDjt9Aof6+DlL327kNH9LJPPFWudEA1IK0BhS lUg/mr31F/mkalwM4E6kUeOr1t9ZlokDe+96ZSIa70sQf8AEPVtXRWMyGKv9LqwKrI 3NK7H4yDG8OdWf25FNF5ZkawSGsl4jCslz+jib4oPDyRhWVNamV9AxWXxOpjvoQ+JY R6QhIsLAxrPKUQRW+06UNZ3i9DpK3Ivsivk3YaZnxe8D7pjZTdZGgxYddhzEC0XXYL 8kvNfsTwkNOdQ== From: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= To: Chen Guokai , paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, rostedt@goodmis.org, mingo@redhat.com, sfr@canb.auug.org.au Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, liaochang1@huawei.com, Chen Guokai Subject: Re: [PATCH v5 6/9] riscv/kprobe: Add code to check if kprobe can be optimized In-Reply-To: <20221224114315.850130-7-chenguokai17@mails.ucas.ac.cn> References: <20221224114315.850130-1-chenguokai17@mails.ucas.ac.cn> <20221224114315.850130-7-chenguokai17@mails.ucas.ac.cn> Date: Mon, 02 Jan 2023 19:04:00 +0100 Message-ID: <87sfgsvmnj.fsf@all.your.base.are.belong.to.us> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Chen Guokai writes: > From: Liao Chang > diff --git a/arch/riscv/kernel/probes/opt.c b/arch/riscv/kernel/probes/op= t.c > index a0d2ab39e3fa..258a283c906d 100644 > --- a/arch/riscv/kernel/probes/opt.c > +++ b/arch/riscv/kernel/probes/opt.c > @@ -271,15 +271,103 @@ static void find_free_registers(struct kprobe *kp,= struct optimized_kprobe *op, > *ra =3D (kw =3D=3D 1UL) ? 0 : __builtin_ctzl(kw & ~1UL); > } >=20=20 > +static bool insn_jump_into_range(unsigned long addr, unsigned long start, > + unsigned long end) > +{ > + kprobe_opcode_t insn =3D *(kprobe_opcode_t *)addr; > + unsigned long target, offset =3D GET_INSN_LENGTH(insn); > + > +#ifdef CONFIG_RISCV_ISA_C > + if (offset =3D=3D RVC_INSN_LEN) { > + if (riscv_insn_is_c_beqz(insn) || riscv_insn_is_c_bnez(insn)) > + target =3D addr + rvc_branch_imme(insn); > + else if (riscv_insn_is_c_jal(insn) || riscv_insn_is_c_j(insn)) > + target =3D addr + rvc_jal_imme(insn); > + else > + target =3D 0; > + return (target >=3D start) && (target < end); > + } > +#endif > + > + if (riscv_insn_is_branch(insn)) > + target =3D addr + rvi_branch_imme(insn); > + else if (riscv_insn_is_jal(insn)) > + target =3D addr + rvi_jal_imme(insn); > + else > + target =3D 0; > + return (target >=3D start) && (target < end); > +} > + > +static int search_copied_insn(unsigned long paddr, struct optimized_kpro= be *op) > +{ > + int i =3D 1; > + unsigned long offset =3D GET_INSN_LENGTH(*(kprobe_opcode_t *)paddr); > + > + while ((i++ < MAX_COPIED_INSN) && (offset < 2 * RVI_INSN_LEN)) { > + if (riscv_probe_decode_insn((probe_opcode_t *)paddr + offset, > + NULL) !=3D INSN_GOOD) If the second argument is NULL, and the insn is auipc, we'll splat with NULL-ptr exception. Hmm, probe_opcode_t is u32, right? And GET_INSN_LENGTH() returns 4 or 2 ...then the pointer arithmetic will be a mess? Bj=C3=B6rn