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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 3A3B7C4363C for ; Wed, 12 May 2021 15:29:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D20061C23 for ; Wed, 12 May 2021 15:29:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233903AbhELP3P (ORCPT ); Wed, 12 May 2021 11:29:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233629AbhELPOQ (ORCPT ); Wed, 12 May 2021 11:14:16 -0400 Received: from ustc.edu.cn (email6.ustc.edu.cn [IPv6:2001:da8:d800::8]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D7F51C06134D for ; Wed, 12 May 2021 08:04:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mail.ustc.edu.cn; s=dkim; h=Received:Date:From:To:Cc:Subject: Message-ID:In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=l7RZxnql5klUqc/JYLPFMAZ9vl2oURQedf Q8t+ojKTY=; b=PNo7qZlmMkXossjSSO6zH2PM1hK5dCmHh8Wc9+XB466E8cHbPG xPyXcqEbQ3Gu6re/GQnWh6VzDfBm8TqxiiEmgKVN6hxedJnmnu+IM0+Py35cTZsW Yw6easWjIPCalX0IwMyG1vSBpFaLVzJ2or6L2OSp7TR51nBxdtjTjW6oM= Received: from xhacker (unknown [101.86.20.15]) by newmailweb.ustc.edu.cn (Coremail) with SMTP id LkAmygDn7Z1F7ptgzS_JAA--.64496S2; Wed, 12 May 2021 23:03:34 +0800 (CST) Date: Wed, 12 May 2021 22:58:19 +0800 From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Masami Hiramatsu Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] riscv: kprobes: Remove redundant kprobe_step_ctx Message-ID: <20210512225819.6756c0b0@xhacker> In-Reply-To: <20210419002919.1a0a539d@xhacker> References: <20210419002919.1a0a539d@xhacker> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-CM-TRANSID: LkAmygDn7Z1F7ptgzS_JAA--.64496S2 X-Coremail-Antispam: 1UD129KBjvJXoWxuryfJr1kZFy8tFW3Ar1DWrg_yoWrKw1kpF ZIk3W3KrZ5Jas5uFy2yw4UZr1Svr48ZrW2kry8C34ftw1ayr13JF1xW3yjyrn8Gr95Kw1a yFy7trW8J3s7AFDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUy2b7Iv0xC_Zr1lb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwV C2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxAIw28IcxkI7VAKI48JMxC20s02 6xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_Jr I_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v2 6r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj4 0_Zr0_Wr1UMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_ Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jnNVgUUUUU= X-CM-SenderInfo: xmv2xttqjtqzxdloh3xvwfhvlgxou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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; > } >