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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A3A6FE6ADC7 for ; Mon, 22 Dec 2025 20:20:00 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6408F10E05C; Mon, 22 Dec 2025 20:20:00 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="cN4WxKIQ"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id CB2F610E05C for ; Mon, 22 Dec 2025 20:19:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1766434798; x=1797970798; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=Wad1xYn9ITBXLFjah8hoq8NNENk+dl5+U6rAGXUpt4U=; b=cN4WxKIQjvUnieKRfhqQ1QBQDAzvm3X3zWvc1zWAkSnHAIYDhP7awKNb Y3oyHWZ3rl59OeSteVhuakmmaM9odQ2i1nUDkfVGBhvGAlXzkpoIkE5N8 1emk7rkGfTEuObpd4J7Kioj+AwQCJ84HwM9P+Ua9lVJqgT3JpE6ucWsd5 32lgjPNv5FXpiUY5fikMvz1i4tnfovFM/zQcSPrCidEts6eYWB70LCcVE oAWyynHs6bZkU19mo9fPE6QQ8LRyI2LpiTbsutAJgYsDQNvcpM5A8VK6U PriB9w2qS0ulicL7iwBVpXit2AGDzpaYPpWWtlU7BhTzwicFU92sJyXqa A==; X-CSE-ConnectionGUID: rCoe4SBXQ/2Ly6L65lLglw== X-CSE-MsgGUID: GlU0ZiNDSVSiz7SMqa09eg== X-IronPort-AV: E=McAfee;i="6800,10657,11650"; a="68335792" X-IronPort-AV: E=Sophos;i="6.21,169,1763452800"; d="scan'208";a="68335792" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2025 12:19:58 -0800 X-CSE-ConnectionGUID: r+9kknibTJeAK0dtuT3YPg== X-CSE-MsgGUID: pXqMuLq9QkS4LOB2wGHjYg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,169,1763452800"; d="scan'208";a="200100902" Received: from dut4086lnl.fm.intel.com ([10.105.10.207]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2025 12:19:58 -0800 From: Jonathan Cavitt To: intel-xe@lists.freedesktop.org Cc: saurabhg.gupta@intel.com, alex.zuo@intel.com, jonathan.cavitt@intel.com, matthew.brost@intel.com, daniele.ceraolospurio@intel.com, rodrigo.vivi@intel.com, michal.wajdeczko@intel.com, stuart.summers@intel.com, ashutosh.dixit@intel.com Subject: [PATCH v3 0/2] drm/xe/guc: Prevent compiler read/write optimization breaks Date: Mon, 22 Dec 2025 20:19:58 +0000 Message-ID: <20251222201957.63245-4-jonathan.cavitt@intel.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" Use READ_ONCE and WRITE_ONCE when operating on ct->state and the g2h_fence->done values to prevent the compiler from ignoring these necessary operations. v2: (Matt Brost) - Add Fixes tags - Add comments v3: - Split into multiple patches (Rodrigo Vivi) v4: - s/xe_guc_ct/guc (Michal W) - Add comments with READ_ONCE and WRITE_ONCE updates (Rodrigo, Stuart, Dixit) - Squash patches with same Fixes target (Rodrigo, Stuart, Dixit) - Add partial comment justifying WRITE_ONCE in guc_ct_change_state before READ_ONCE in xe_guc_ct_enabled is added (Rodrigo Vivi) - Update above comment when adding READ_ONCE to xe_guc_ct_enabled (jcavitt) v4: (Matt Brost) - Squash patches operating on the same value together - Remove unnecessary Fixes tags - Add READ_ONCEs to pair with WRITE_ONCEs on g2h_fence->done Suggested-by: Matthew Brost Suggested-by: Rodrigo Vivi Signed-off-by: Jonathan Cavitt Cc: Daniele Ceraolo Spurio Cc: Rodrigo Vivi Cc: Michal Wajdeczko Cc: Stuart Summers Cc: Ashutosh Dixit Jonathan Cavitt (2): drm/xe/guc: READ/WRITE_ONCE g2h_fence->done drm/xe/guc: READ/WRITE_ONCE ct->state drivers/gpu/drm/xe/xe_guc_ct.c | 21 ++++++++++++++++----- drivers/gpu/drm/xe/xe_guc_ct.h | 6 ++++-- 2 files changed, 20 insertions(+), 7 deletions(-) -- 2.43.0