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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 9E708C433F5 for ; Fri, 17 Sep 2021 05:58:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7662E61019 for ; Fri, 17 Sep 2021 05:58:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244931AbhIQF7p (ORCPT ); Fri, 17 Sep 2021 01:59:45 -0400 Received: from foss.arm.com ([217.140.110.172]:48300 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230133AbhIQF7o (ORCPT ); Fri, 17 Sep 2021 01:59:44 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 738F331B; Thu, 16 Sep 2021 22:58:22 -0700 (PDT) Received: from a077416.arm.com (unknown [10.163.42.222]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 595343F5A1; Thu, 16 Sep 2021 22:58:19 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Mark Rutland , Vincenzo Frascino , Kevin Brodsky , Amit Daniel Kachhap , Catalin Marinas , Will Deacon Subject: [PATCH v2] arm64/traps: Avoid unnecessary kernel/user pointer conversion Date: Fri, 17 Sep 2021 11:28:11 +0530 Message-Id: <20210917055811.22341-1-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Annotating a pointer from kernel to __user and then back again requires an extra __force annotation to silent sparse warning. In call_undef_hook() this unnecessary complexity can be avoided by modifying the intermediate user pointer to unsigned long. This way there is no inter-changeable use of user and kernel pointers and the code is consistent. Note: This patch adds no functional changes to code. Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Amit Daniel Kachhap --- Changes from v1: * Instead of directly using instruction_pointer() for kernel pointers, modified the pc type from void __user * to unsigned long as suggested by Mark Rutland. arch/arm64/kernel/traps.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index b03e383d944a..09236751283e 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -400,11 +400,11 @@ static int call_undef_hook(struct pt_regs *regs) unsigned long flags; u32 instr; int (*fn)(struct pt_regs *regs, u32 instr) = NULL; - void __user *pc = (void __user *)instruction_pointer(regs); + unsigned long pc = instruction_pointer(regs); if (!user_mode(regs)) { __le32 instr_le; - if (get_kernel_nofault(instr_le, (__force __le32 *)pc)) + if (get_kernel_nofault(instr_le, (__le32 *)pc)) goto exit; instr = le32_to_cpu(instr_le); } else if (compat_thumb_mode(regs)) { -- 2.17.1