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 X-Spam-Level: X-Spam-Status: No, score=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C218C2B9F8 for ; Tue, 25 May 2021 14:45:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2EFB86141C for ; Tue, 25 May 2021 14:45:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234146AbhEYOqn (ORCPT ); Tue, 25 May 2021 10:46:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:47126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232939AbhEYOqk (ORCPT ); Tue, 25 May 2021 10:46:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B958A6141C; Tue, 25 May 2021 14:45:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621953911; bh=jfWp5vialmXhYcXsdvLggfVIv1bcNp7z6bzNnIfhMJs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=lyU0XUfjokFn6Duv+OPmiSjb1JOVme62avzrZz2hHvx1oFvh07TXcqjNc7vTtydze 9GU04pIGPwo1dv0rmUZZaX068G8FEAM+YtGrLHhYLfsvEwTrP8DWcmSaHoZff6IH3a qKhyCIxNvROpdTzWZeJdKieBQj0EFkzeAmOYmvxmnMeesMpvQV2AuJ3ci3i3JVmMLU VrpviY6aghQ2FKhDrEXVejZQ4kPEJOr9f6OrUwWz7Zlzm40CXnnouGPHqLE5tQx2BB te+qUNejwrTWcjIPdEHR2BPVyDZmBtyB/j4Ra11amW2TL4jCbYm437zf/Mlkn3YAXD WQZ9fr5DvMEqQ== Date: Tue, 25 May 2021 23:45:07 +0900 From: Masami Hiramatsu To: Jisheng Zhang Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] riscv: kprobes: Remove redundant kprobe_step_ctx Message-Id: <20210525234507.2a576f91d157eba18eb4306a@kernel.org> In-Reply-To: <20210512225819.6756c0b0@xhacker> References: <20210419002919.1a0a539d@xhacker> <20210512225819.6756c0b0@xhacker> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jisheng, On Wed, 12 May 2021 22:58:19 +0800 Jisheng Zhang wrote: > On Mon, 19 Apr 2021 00:29:19 +0800 > Jisheng Zhang wrote: > > > From: Jisheng Zhang > > > > Inspired by commit ba090f9cafd5 ("arm64: kprobes: Remove redundant > > kprobe_step_ctx"), the ss_pending and match_addr of kprobe_step_ctx > > are redundant because those can be replaced by KPROBE_HIT_SS and > > &cur_kprobe->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode) > > respectively. > > > > Remove the kprobe_step_ctx to simplify the code. > > Hi all, > > This patch can still be applied to 5.13-rc1, could you please review? Let me > know if a rebase on 5.13-rc1 is needed. As far as I compared with arm64 code, this looks good to me. Reviewed-by: Masami Hiramatsu Thanks, > > Thanks > > > > > Signed-off-by: Jisheng Zhang > > --- > > arch/riscv/include/asm/kprobes.h | 7 ------ > > arch/riscv/kernel/probes/kprobes.c | 40 +++++++----------------------- > > 2 files changed, 9 insertions(+), 38 deletions(-) > > > > diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h > > index 4647d38018f6..9ea9b5ec3113 100644 > > --- a/arch/riscv/include/asm/kprobes.h > > +++ b/arch/riscv/include/asm/kprobes.h > > @@ -29,18 +29,11 @@ struct prev_kprobe { > > unsigned int status; > > }; > > > > -/* Single step context for kprobe */ > > -struct kprobe_step_ctx { > > - unsigned long ss_pending; > > - unsigned long match_addr; > > -}; > > - > > /* per-cpu kprobe control block */ > > struct kprobe_ctlblk { > > unsigned int kprobe_status; > > unsigned long saved_status; > > struct prev_kprobe prev_kprobe; > > - struct kprobe_step_ctx ss_ctx; > > }; > > > > void arch_remove_kprobe(struct kprobe *p); > > diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c > > index 8c1f7a30aeed..4c1ad5536748 100644 > > --- a/arch/riscv/kernel/probes/kprobes.c > > +++ b/arch/riscv/kernel/probes/kprobes.c > > @@ -17,7 +17,7 @@ DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; > > DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); > > > > static void __kprobes > > -post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *); > > +post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *); > > > > static void __kprobes arch_prepare_ss_slot(struct kprobe *p) > > { > > @@ -43,7 +43,7 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs) > > p->ainsn.api.handler((u32)p->opcode, > > (unsigned long)p->addr, regs); > > > > - post_kprobe_handler(kcb, regs); > > + post_kprobe_handler(p, kcb, regs); > > } > > > > int __kprobes arch_prepare_kprobe(struct kprobe *p) > > @@ -149,21 +149,6 @@ static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb, > > regs->status = kcb->saved_status; > > } > > > > -static void __kprobes > > -set_ss_context(struct kprobe_ctlblk *kcb, unsigned long addr, struct kprobe *p) > > -{ > > - unsigned long offset = GET_INSN_LENGTH(p->opcode); > > - > > - kcb->ss_ctx.ss_pending = true; > > - kcb->ss_ctx.match_addr = addr + offset; > > -} > > - > > -static void __kprobes clear_ss_context(struct kprobe_ctlblk *kcb) > > -{ > > - kcb->ss_ctx.ss_pending = false; > > - kcb->ss_ctx.match_addr = 0; > > -} > > - > > static void __kprobes setup_singlestep(struct kprobe *p, > > struct pt_regs *regs, > > struct kprobe_ctlblk *kcb, int reenter) > > @@ -182,8 +167,6 @@ static void __kprobes setup_singlestep(struct kprobe *p, > > /* prepare for single stepping */ > > slot = (unsigned long)p->ainsn.api.insn; > > > > - set_ss_context(kcb, slot, p); /* mark pending ss */ > > - > > /* IRQs and single stepping do not mix well. */ > > kprobes_save_local_irqflag(kcb, regs); > > > > @@ -219,13 +202,8 @@ static int __kprobes reenter_kprobe(struct kprobe *p, > > } > > > > static void __kprobes > > -post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs) > > +post_kprobe_handler(struct kprobe *cur, struct kprobe_ctlblk *kcb, struct pt_regs *regs) > > { > > - struct kprobe *cur = kprobe_running(); > > - > > - if (!cur) > > - return; > > - > > /* return addr restore if non-branching insn */ > > if (cur->ainsn.api.restore != 0) > > regs->epc = cur->ainsn.api.restore; > > @@ -355,16 +333,16 @@ bool __kprobes > > kprobe_single_step_handler(struct pt_regs *regs) > > { > > struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); > > + unsigned long addr = instruction_pointer(regs); > > + struct kprobe *cur = kprobe_running(); > > > > - if ((kcb->ss_ctx.ss_pending) > > - && (kcb->ss_ctx.match_addr == instruction_pointer(regs))) { > > - clear_ss_context(kcb); /* clear pending ss */ > > - > > + if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) && > > + ((unsigned long)&cur->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode) == addr)) { > > kprobes_restore_local_irqflag(kcb, regs); > > - > > - post_kprobe_handler(kcb, regs); > > + post_kprobe_handler(cur, kcb, regs); > > return true; > > } > > + /* not ours, kprobes should ignore it */ > > return false; > > } > > > > -- Masami Hiramatsu