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=-11.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 03AD4C433E6 for ; Sat, 29 Aug 2020 09:31:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D00E520825 for ; Sat, 29 Aug 2020 09:31:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598693505; bh=mRFSDrdb3CJe2f+LAM7xJ8zLaomR+oMA2NdfHPPa/t0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=bJ55Mqlv+ZHPF0YXsnqxlP5+KsEo12Ab+UzTUPkuDnGpi9OXNT1WZ6KcjhKGlTHCC ZySlEw/oONUEyau7J6gntt4yz/bJUVB+Rsy4znPMk1czayKkI99QIg5lpQH2SnybSq cWsJ2F7TAatHze7U6eCx9ISStL9pAjprr7lg6MoA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726798AbgH2Jbp (ORCPT ); Sat, 29 Aug 2020 05:31:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:33456 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726405AbgH2Jbo (ORCPT ); Sat, 29 Aug 2020 05:31:44 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 29A4320791; Sat, 29 Aug 2020 09:31:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598693503; bh=mRFSDrdb3CJe2f+LAM7xJ8zLaomR+oMA2NdfHPPa/t0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=0yxm7IYZjnpWoncFmotRWzVmXnF0Xg4sF5JIoCi82xNx/OASmYj1Az+HI5i87X4sl IxxhQXmB2/34D3+Ma3jTxSNDJf5x8IgXSf0ERSyv1a/e9t+O2sX4gHr2Ozx2/nrK5f vYnTsiFcyBN3248K09lO/ot/VYcAVmDXe37yQ6ww= Date: Sat, 29 Aug 2020 18:31:39 +0900 From: Masami Hiramatsu To: Guo Ren Cc: Linux Kernel Mailing List , Peter Zijlstra , Eddy Wu , x86@kernel.org, "David S . Miller" , Steven Rostedt , Ingo Molnar , "Naveen N . Rao" , Anil S Keshavamurthy , linux-arch Subject: Re: [PATCH v3 06/16] csky: kprobes: Use generic kretprobe trampoline handler Message-Id: <20200829183139.9bf2877cf4f1a436b360c722@kernel.org> In-Reply-To: References: <159854631442.736475.5062989489155389472.stgit@devnote2> <159854636764.736475.9112286781925119117.stgit@devnote2> 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 Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Fri, 28 Aug 2020 20:34:22 +0800 Guo Ren wrote: > Looks more clear. > > Acked-by: Guo Ren Thanks Guo! I'll add it to the next version. > > On Fri, Aug 28, 2020 at 12:39 AM Masami Hiramatsu wrote: > > > > Signed-off-by: Masami Hiramatsu > > --- > > arch/csky/kernel/probes/kprobes.c | 78 +------------------------------------ > > 1 file changed, 3 insertions(+), 75 deletions(-) > > > > diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c > > index f0f733b7ac5a..a891fb422e76 100644 > > --- a/arch/csky/kernel/probes/kprobes.c > > +++ b/arch/csky/kernel/probes/kprobes.c > > @@ -404,87 +404,15 @@ int __init arch_populate_kprobe_blacklist(void) > > > > void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs) > > { > > - struct kretprobe_instance *ri = NULL; > > - struct hlist_head *head, empty_rp; > > - struct hlist_node *tmp; > > - unsigned long flags, orig_ret_address = 0; > > - unsigned long trampoline_address = > > - (unsigned long)&kretprobe_trampoline; > > - kprobe_opcode_t *correct_ret_addr = NULL; > > - > > - INIT_HLIST_HEAD(&empty_rp); > > - kretprobe_hash_lock(current, &head, &flags); > > - > > - /* > > - * It is possible to have multiple instances associated with a given > > - * task either because multiple functions in the call path have > > - * return probes installed on them, and/or more than one > > - * return probe was registered for a target function. > > - * > > - * We can handle this because: > > - * - instances are always pushed into the head of the list > > - * - when multiple return probes are registered for the same > > - * function, the (chronologically) first instance's ret_addr > > - * will be the real return address, and all the rest will > > - * point to kretprobe_trampoline. > > - */ > > - hlist_for_each_entry_safe(ri, tmp, head, hlist) { > > - if (ri->task != current) > > - /* another task is sharing our hash bucket */ > > - continue; > > - > > - orig_ret_address = (unsigned long)ri->ret_addr; > > - > > - if (orig_ret_address != trampoline_address) > > - /* > > - * This is the real return address. Any other > > - * instances associated with this task are for > > - * other calls deeper on the call stack > > - */ > > - break; > > - } > > - > > - kretprobe_assert(ri, orig_ret_address, trampoline_address); > > - > > - correct_ret_addr = ri->ret_addr; > > - hlist_for_each_entry_safe(ri, tmp, head, hlist) { > > - if (ri->task != current) > > - /* another task is sharing our hash bucket */ > > - continue; > > - > > - orig_ret_address = (unsigned long)ri->ret_addr; > > - if (ri->rp && ri->rp->handler) { > > - __this_cpu_write(current_kprobe, &ri->rp->kp); > > - get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; > > - ri->ret_addr = correct_ret_addr; > > - ri->rp->handler(ri, regs); > > - __this_cpu_write(current_kprobe, NULL); > > - } > > - > > - recycle_rp_inst(ri, &empty_rp); > > - > > - if (orig_ret_address != trampoline_address) > > - /* > > - * This is the real return address. Any other > > - * instances associated with this task are for > > - * other calls deeper on the call stack > > - */ > > - break; > > - } > > - > > - kretprobe_hash_unlock(current, &flags); > > - > > - hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { > > - hlist_del(&ri->hlist); > > - kfree(ri); > > - } > > - return (void *)orig_ret_address; > > + return (void *)kretprobe_trampoline_handler(regs, > > + (unsigned long)&kretprobe_trampoline, NULL); > > } > > > > void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, > > struct pt_regs *regs) > > { > > ri->ret_addr = (kprobe_opcode_t *)regs->lr; > > + ri->fp = NULL; > > regs->lr = (unsigned long) &kretprobe_trampoline; > > } > > > > > > > -- > Best Regards > Guo Ren > > ML: https://lore.kernel.org/linux-csky/ -- Masami Hiramatsu