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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EA88C433FE for ; Fri, 15 Oct 2021 02:59:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E153611CC for ; Fri, 15 Oct 2021 02:59:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235117AbhJODBR (ORCPT ); Thu, 14 Oct 2021 23:01:17 -0400 Received: from linux.microsoft.com ([13.77.154.182]:58164 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235115AbhJODBM (ORCPT ); Thu, 14 Oct 2021 23:01:12 -0400 Received: from x64host.home (unknown [47.187.212.181]) by linux.microsoft.com (Postfix) with ESMTPSA id 90ED620B9D1E; Thu, 14 Oct 2021 19:59:05 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 90ED620B9D1E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1634266746; bh=g5fdmzSduoUMkjQHmQa/fhtE8jC0SUmUZcxIW9qvvbk=; h=From:To:Subject:Date:In-Reply-To:References:From; b=lBvZQzvd1+eA5IQSDbS3fFDDPe+shGmQRIdrhpVc3ctrdoWHLDAQ6RHSe9A8Vc0yD R3rD66EQXo5BCyzisFaAz4KISEwSkC25Zj44GNND4JRihiKm2zDFwPem1hngXIzwB/ rVn3Bnq5tTi/W85c/yiOLDYczo7JQQPoZ7W0SW0A= From: madvenka@linux.microsoft.com To: mark.rutland@arm.com, broonie@kernel.org, jpoimboe@redhat.com, ardb@kernel.org, nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com, catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com Subject: [PATCH v10 03/11] arm64: Make get_wchan() use arch_stack_walk() Date: Thu, 14 Oct 2021 21:58:39 -0500 Message-Id: <20211015025847.17694-4-madvenka@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211015025847.17694-1-madvenka@linux.microsoft.com> References: <20211015025847.17694-1-madvenka@linux.microsoft.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org From: "Madhavan T. Venkataraman" Currently, get_wchan() in ARM64 code walks the stack using start_backtrace() and unwind_frame(). Make it use arch_stack_walk() instead. This makes maintenance easier. Signed-off-by: Madhavan T. Venkataraman --- arch/arm64/kernel/process.c | 38 ++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index c8989b999250..48ed89acce0d 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -544,11 +544,27 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, return last; } +struct wchan_info { + unsigned long pc; + int count; +}; + +static bool get_wchan_cb(void *arg, unsigned long pc) +{ + struct wchan_info *wchan_info = arg; + + if (!in_sched_functions(pc)) { + wchan_info->pc = pc; + return false; + } + return wchan_info->count++ < 16; +} + unsigned long get_wchan(struct task_struct *p) { - struct stackframe frame; - unsigned long stack_page, ret = 0; - int count = 0; + unsigned long stack_page; + struct wchan_info wchan_info; + if (!p || p == current || task_is_running(p)) return 0; @@ -556,20 +572,12 @@ unsigned long get_wchan(struct task_struct *p) if (!stack_page) return 0; - start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p)); + wchan_info.pc = 0; + wchan_info.count = 0; + arch_stack_walk(get_wchan_cb, &wchan_info, p, NULL); - do { - if (unwind_frame(p, &frame)) - goto out; - if (!in_sched_functions(frame.pc)) { - ret = frame.pc; - goto out; - } - } while (count++ < 16); - -out: put_task_stack(p); - return ret; + return wchan_info.pc; } unsigned long arch_align_stack(unsigned long sp) -- 2.25.1