From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53000 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938654AbcIEQyP (ORCPT ); Mon, 5 Sep 2016 12:54:15 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Liav Rehana , Alexey Brodkin , Vineet Gupta Subject: [PATCH 4.4 074/113] ARC: use correct offset in pt_regs for saving/restoring user mode r25 Date: Mon, 5 Sep 2016 18:44:37 +0200 Message-Id: <20160905164352.337288222@linuxfoundation.org> In-Reply-To: <20160905164349.217621339@linuxfoundation.org> References: <20160905164349.217621339@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liav Rehana commit 86147e3cfa5e118b61e78f4f0bf29e920dcbd477 upstream. User mode callee regs are explicitly collected before signal delivery or breakpoint trap. r25 is special for kernel as it serves as task pointer, so user mode value is clobbered very early. It is saved in pt_regs where generally only scratch (aka caller saved) regs are saved. The code to access the corresponding pt_regs location had a subtle bug as it was using load/store with scaling of offset, whereas the offset was already byte wise correct. So fix this by replacing LD.AS with a standard LD Signed-off-by: Liav Rehana Reviewed-by: Alexey Brodkin [vgupta: rewrote title and commit log] Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman --- arch/arc/include/asm/entry.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arc/include/asm/entry.h +++ b/arch/arc/include/asm/entry.h @@ -142,7 +142,7 @@ #ifdef CONFIG_ARC_CURR_IN_REG ; Retrieve orig r25 and save it with rest of callee_regs - ld.as r12, [r12, PT_user_r25] + ld r12, [r12, PT_user_r25] PUSH r12 #else PUSH r25 @@ -198,7 +198,7 @@ ; SP is back to start of pt_regs #ifdef CONFIG_ARC_CURR_IN_REG - st.as r12, [sp, PT_user_r25] + st r12, [sp, PT_user_r25] #endif .endm