From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0121.outbound.protection.outlook.com ([104.47.42.121]:43475 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935239AbeCHE6T (ORCPT ); Wed, 7 Mar 2018 23:58:19 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Logan Gunthorpe , Jyri Sarha , Arnd Bergmann , Tomi Valkeinen , David Airlie , Sasha Levin Subject: [PATCH AUTOSEL for 4.14 27/67] drm/tilcdc: ensure nonatomic iowrite64 is not used Date: Thu, 8 Mar 2018 04:57:43 +0000 Message-ID: <20180308045641.7814-27-alexander.levin@microsoft.com> References: <20180308045641.7814-1-alexander.levin@microsoft.com> In-Reply-To: <20180308045641.7814-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Logan Gunthorpe [ Upstream commit 4e5ca2d930aa8714400aedf4bf1dc959cb04280f ] Add a check to ensure iowrite64 is only used if it is atomic. It was decided in [1] that the tilcdc driver should not be using an atomic operation (so it was left out of this patchset). However, it turns out that through the drm code, a nonatomic header is actually included: include/linux/io-64-nonatomic-lo-hi.h is included from include/drm/drm_os_linux.h:9:0, from include/drm/drmP.h:74, from include/drm/drm_modeset_helper.h:26, from include/drm/drm_atomic_helper.h:33, from drivers/gpu/drm/tilcdc/tilcdc_crtc.c:19: And thus, without this change, this patchset would inadvertantly change the behaviour of the tilcdc driver. [1] lkml.kernel.org/r/CAK8P3a2HhO_zCnsTzq7hmWSz5La5Thu19FWZpun16iMnyyNreQ@m= ail.gmail.com Signed-off-by: Logan Gunthorpe Reviewed-by: Andy Shevchenko Cc: Jyri Sarha Cc: Arnd Bergmann Cc: Tomi Valkeinen Cc: David Airlie Signed-off-by: Jyri Sarha Signed-off-by: Sasha Levin --- drivers/gpu/drm/tilcdc/tilcdc_regs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/tilcdc/tilcdc_regs.h b/drivers/gpu/drm/tilcdc/= tilcdc_regs.h index 9d528c0a67a4..5048ebb86835 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_regs.h +++ b/drivers/gpu/drm/tilcdc/tilcdc_regs.h @@ -133,7 +133,7 @@ static inline void tilcdc_write64(struct drm_device *de= v, u32 reg, u64 data) struct tilcdc_drm_private *priv =3D dev->dev_private; volatile void __iomem *addr =3D priv->mmio + reg; =20 -#ifdef iowrite64 +#if defined(iowrite64) && !defined(iowrite64_is_nonatomic) iowrite64(data, addr); #else __iowmb(); --=20 2.14.1