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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, 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 55192C433E6 for ; Fri, 28 Aug 2020 12:34:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 319942078A for ; Fri, 28 Aug 2020 12:34:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598618093; bh=+ZC7vfEqt3vatoNYBNCOkUx0FbTQCSqA61BSY3oIaYI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=m0knKBHfgWmNv8ITTg6BghycTr6vFFgo3RWAmFrENh2teYQHg/Q9bmVAtJ8gPE8kk MuX9kZd5N7zv6mbGIuspxDb6MdaXjH3QnyokFD4IUP46xhzyC8bweI5yksOPR/7EDg Hdmtkg6IyxSr2N99e980ftDRS1944WwWrx7BHm7o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729336AbgH1Mev (ORCPT ); Fri, 28 Aug 2020 08:34:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:43174 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729123AbgH1Meg (ORCPT ); Fri, 28 Aug 2020 08:34:36 -0400 Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com [209.85.167.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B44FD21556; Fri, 28 Aug 2020 12:34:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598618076; bh=+ZC7vfEqt3vatoNYBNCOkUx0FbTQCSqA61BSY3oIaYI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=MP54G526OTSuUO0SMqEa41is5mB4meDtVm4ATTrscGCJ/0z90lrJGLApoqnNqFmKp affosG+UNDAWfRzc9IGvtCNGIk6ijYdHFlKs6YfP8A3GA2h9obQAWHUWKHARzyi/rM HQuYy4+FDdst0V8uP5kkQfFbeRySb3sLvgPHcRlU= Received: by mail-lf1-f51.google.com with SMTP id y17so620765lfa.8; Fri, 28 Aug 2020 05:34:35 -0700 (PDT) X-Gm-Message-State: AOAM532NWYPg0s483yyxWZJsTiX0q0+ffmr4yKOlY1GFrUktAFs0d6rg RYMc1xJvo/prbxaAlkmZghwOYHXB7r+Dy9Z0rBM= X-Google-Smtp-Source: ABdhPJwPtXOMRGNu43110Ft0LpuiT1efN8BBGxHEgNOP5buSs9W1RComAIOA+C5bZ6vYzpGzogRfDZyoAT9knSKwSgY= X-Received: by 2002:ac2:4ecc:: with SMTP id p12mr713259lfr.212.1598618073917; Fri, 28 Aug 2020 05:34:33 -0700 (PDT) MIME-Version: 1.0 References: <159854631442.736475.5062989489155389472.stgit@devnote2> <159854636764.736475.9112286781925119117.stgit@devnote2> In-Reply-To: <159854636764.736475.9112286781925119117.stgit@devnote2> From: Guo Ren Date: Fri, 28 Aug 2020 20:34:22 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 06/16] csky: kprobes: Use generic kretprobe trampoline handler To: Masami Hiramatsu 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 Content-Type: text/plain; charset="UTF-8" Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Looks more clear. Acked-by: Guo Ren 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/