From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932097AbdBUTRY (ORCPT ); Tue, 21 Feb 2017 14:17:24 -0500 Received: from mail-pg0-f65.google.com ([74.125.83.65]:34665 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754631AbdBUTOC (ORCPT ); Tue, 21 Feb 2017 14:14:02 -0500 From: Stafford Horne To: Jonas Bonn , Stefan Kristiansson Cc: linux@roeck-us.net, openrisc@lists.librecores.org, linux-kernel@vger.kernel.org, Stafford Horne Subject: [PATCH v3 25/25] openrisc: head: Init r0 to 0 on start Date: Wed, 22 Feb 2017 04:11:54 +0900 Message-Id: <20913e0a776dda47da0d95e7769867636f180f90.1487702890.git.shorne@gmail.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Originally openrisc spec 0 specified that r0 would be wired to ground. This is no longer the case. r0 is not guaranteed to be 0 at init, so we need to initialize it to 0 before using it. Also, if we are clearing r0 we cant use r0 to clear itself. Change the the CLEAR_GPR macro to use movhi for clearing. Signed-off-by: Stafford Horne --- arch/openrisc/kernel/head.S | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S index 573e131..e8a1784 100644 --- a/arch/openrisc/kernel/head.S +++ b/arch/openrisc/kernel/head.S @@ -35,7 +35,7 @@ l.add rd,rd,rs #define CLEAR_GPR(gpr) \ - l.or gpr,r0,r0 + l.movhi gpr,0x0 #define LOAD_SYMBOL_2_GPR(gpr,symbol) \ l.movhi gpr,hi(symbol) ;\ @@ -443,6 +443,9 @@ _dispatch_do_ipage_fault: __HEAD .global _start _start: + /* Init r0 to zero as per spec */ + CLEAR_GPR(r0) + /* save kernel parameters */ l.or r25,r0,r3 /* pointer to fdt */ -- 2.9.3