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=-20.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 E5693C433EF for ; Fri, 24 Sep 2021 07:36:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4B2760E90 for ; Fri, 24 Sep 2021 07:36:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231921AbhIXHiY (ORCPT ); Fri, 24 Sep 2021 03:38:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:48866 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244344AbhIXHiY (ORCPT ); Fri, 24 Sep 2021 03:38:24 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 964F260E08; Fri, 24 Sep 2021 07:36:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632469011; bh=LpHb8A+wUT0ue+o052SvF/xrnFqr5rMpVkjCEtBXzBg=; h=From:To:Cc:Subject:Date:From; b=EONxVMBVcJeRE2R02Y+usrP5eWq+D26Y6GvrrJrJSftkXNjp/5qOKVff17PnXtwGe qdswHKFQHmSz43b3SZzvKkOEgjhpjGkSxjEJn22FAx3DBEqjtDd7ZRnqnuNmHGwkqE VnAsdJQF+frVHQMqIxfoMHkm2hJKTXfzaLFb9OYOk2IfWK5U3VTxjrSACxFwTD6WWV 5EY1SOzG/MIZkAMG+K+LRzBuI35qcBbB25eYsFTKAke05/Wmq+tPbGoXkJYP083dQn UZQjdFYefr/0rA/OaDq+wzpBu9XvXYPV4y5OhgWnxxd/krrWieK6JkVvdgzOr2o21+ ttgHYiuW0BFKw== From: guoren@kernel.org To: guoren@kernel.org Cc: linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, Guo Ren , Al Viro Subject: [PATCH] csky: Fixup regs.sr broken in ptrace Date: Fri, 24 Sep 2021 15:36:45 +0800 Message-Id: <20210924073645.1145907-1-guoren@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org From: Guo Ren gpr_get() return the entire pt_regs (include sr) to userspace, if we don't restore the C bit in gpr_set, it may break the ALU result in that context. So the C flag bit is part of gpr context, that's why riscv totally remove the C bit in the ISA. That makes sr reg clear from userspace to supervisor privilege. Signed-off-by: Guo Ren Cc: Al Viro --- arch/csky/kernel/ptrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c index 0105ac81b432..1a5f54e0d272 100644 --- a/arch/csky/kernel/ptrace.c +++ b/arch/csky/kernel/ptrace.c @@ -99,7 +99,8 @@ static int gpr_set(struct task_struct *target, if (ret) return ret; - regs.sr = task_pt_regs(target)->sr; + /* BIT(0) of regs.sr is Condition Code/Carry bit */ + regs.sr = (regs.sr & BIT(0)) | (task_pt_regs(target)->sr & ~BIT(0)); #ifdef CONFIG_CPU_HAS_HILO regs.dcsr = task_pt_regs(target)->dcsr; #endif -- 2.25.1