From patchwork Tue Mar 3 17:42:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 11418665 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EF9C114E3 for ; Tue, 3 Mar 2020 18:12:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D07A420866 for ; Tue, 3 Mar 2020 18:12:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583259122; bh=2iJwWasVf+CDL+1GCCg+dC8safmJqLUpKJYeW7tEWz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DpAAYCgtBngnNhgcnaqYl+LvfPMulekOT75ZpMnDtNServxyCf3bL3yJMz8P+vTPX xBriv9HKv5uCdFiQt5OGNOKbFk+Rnj1xzt8edsW1Z56BkiAwDL8YKVK7K5pRE5dAUv 04R4ZUOPNtu9HSaVZw8YUDczMFWyy/xbgxtu9E94= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730785AbgCCRtJ (ORCPT ); Tue, 3 Mar 2020 12:49:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:56380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730830AbgCCRtI (ORCPT ); Tue, 3 Mar 2020 12:49:08 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 138E1208C3; Tue, 3 Mar 2020 17:49:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257747; bh=2iJwWasVf+CDL+1GCCg+dC8safmJqLUpKJYeW7tEWz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eZslrvy0Ba4gQV2SbhU4DRKilc+eQqDArk8aqPVs5+6wI4UFKWsfcmpoBjbO7kknX flXF+RX4z6qiYsa3oA4JoR4PPaRFHwhNxP77VQhHOR+6VNtB+n2uiFWejSsg70lXRD XhthIfxzzuiOPUmsKWhYx2VumXf3WQJ1YilkmOjw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Tomlinson , Chris Packham , Paul Burton , linux-mips@vger.kernel.org Subject: [PATCH 5.5 114/176] MIPS: cavium_octeon: Fix syncw generation. Date: Tue, 3 Mar 2020 18:42:58 +0100 Message-Id: <20200303174318.020233777@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174304.593872177@linuxfoundation.org> References: <20200303174304.593872177@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Mark Tomlinson commit 97e914b7de3c943011779b979b8093fdc0d85722 upstream. The Cavium Octeon CPU uses a special sync instruction for implementing wmb, and due to a CPU bug, the instruction must appear twice. A macro had been defined to hide this: #define __SYNC_rpt(type) (1 + (type == __SYNC_wmb)) which was intended to evaluate to 2 for __SYNC_wmb, and 1 for any other type of sync. However, this expression is evaluated by the assembler, and not the compiler, and the result of '==' in the assembler is 0 or -1, not 0 or 1 as it is in C. The net result was wmb() producing no code at all. The simple fix in this patch is to change the '+' to '-'. Fixes: bf92927251b3 ("MIPS: barrier: Add __SYNC() infrastructure") Signed-off-by: Mark Tomlinson Tested-by: Chris Packham Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/mips/include/asm/sync.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/mips/include/asm/sync.h +++ b/arch/mips/include/asm/sync.h @@ -155,9 +155,11 @@ * effective barrier as noted by commit 6b07d38aaa52 ("MIPS: Octeon: Use * optimized memory barrier primitives."). Here we specify that the affected * sync instructions should be emitted twice. + * Note that this expression is evaluated by the assembler (not the compiler), + * and that the assembler evaluates '==' as 0 or -1, not 0 or 1. */ #ifdef CONFIG_CPU_CAVIUM_OCTEON -# define __SYNC_rpt(type) (1 + (type == __SYNC_wmb)) +# define __SYNC_rpt(type) (1 - (type == __SYNC_wmb)) #else # define __SYNC_rpt(type) 1 #endif