From patchwork Mon Oct 9 18:28:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 115283 Delivered-To: patch@linaro.org Received: by 10.140.22.163 with SMTP id 32csp2862320qgn; Mon, 9 Oct 2017 11:30:47 -0700 (PDT) X-Google-Smtp-Source: AOwi7QBpA1EVDHEf7VR1hRoy6ujDGes5arsR3t7CqGnyDRPDwrkn9qLBFHHx+a33GqyraytvubxM X-Received: by 10.98.141.215 with SMTP id p84mr10850019pfk.160.1507573847465; Mon, 09 Oct 2017 11:30:47 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1507573847; cv=none; d=google.com; s=arc-20160816; b=a7VNTuf/T7S8g+qEduFQ8LhYXVdSUk/86cBC+iAxwX9l0Wnd76DKrX2mWW4G3x/FOU y5fLB4QD9dVspEZ3mxJhYrhJR5ej6Cx9BunjyRPHVWaWSs0VtSok7OgLOzmZT3JT3UA6 hVmzH06j7xLcF5KM58FDfrsKjjhCab/9au64LQ3UHRq+Xz2F2JFPfRL5SjYrZ84e0hLQ kgyhU5L5Vo7+Zp1gSPvzr1b0cl3rouzw2RYW2tD25M+D2mF4/slxT/fUwg7DfDNSnlzu QeJ0SWhSWUS6T3JkBZdJc8MGLUoHG6UlfYwg2j0DGU6NpzHIgf+CPFvDCGA/6lX/8Ewu A6Tw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=xsLc8Kl2+L2/R8dyHmh1HcunntQwrxIssb3AjvUw6as=; b=z1KlWIP56veIjaGK72Oh8gfBProVVpWjXMz6G1Tp4guyRJl6LuYXPWMfNtvDOk38SW kdiIgsOItPofKB0FwVm9K6+SzOcXtCumHwiQSV5lMhIyrRNmSQTxI7EHiNIsW8wmjoPc d52/XKBHFE4EIGlv24VAz3vKlKGou/MllfQV/oyFArmIV41mnczuRoeRudzJOjPknY0J F9Yr56v9g2/yDptZWFOTPfAq3gPxAN2MFC7CLkQOpiJSnIz8BudLYMeLHCZKJcGwDgQf +wL50wwvRAJVMYNhA4ktPULGz30dejPvWkrUyZTGasgvYPo9vuMNdDEw9tIFRpB6KrLP cnxQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id r25si7451145pfk.524.2017.10.09.11.30.47; Mon, 09 Oct 2017 11:30:47 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755224AbdJISap (ORCPT + 26 others); Mon, 9 Oct 2017 14:30:45 -0400 Received: from foss.arm.com ([217.140.101.70]:33756 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755110AbdJISak (ORCPT ); Mon, 9 Oct 2017 14:30:40 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7114815AD; Mon, 9 Oct 2017 11:30:40 -0700 (PDT) Received: from leverpostej.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 8649F3F483; Mon, 9 Oct 2017 11:30:39 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: Mark Rutland , Jonathan Hunter , Thierry Reding Subject: [PATCH 03/13] firmware/ivc: kill off ACCESS_ONCE() Date: Mon, 9 Oct 2017 19:28:40 +0100 Message-Id: <1507573730-8083-4-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1507573730-8083-1-git-send-email-mark.rutland@arm.com> References: <1507573730-8083-1-git-send-email-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org workqueue: kill off ACCESS_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the Tegra IVC code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland Cc: Jonathan Hunter Cc: Thierry Reding --- drivers/firmware/tegra/ivc.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) -- 1.9.1 diff --git a/drivers/firmware/tegra/ivc.c b/drivers/firmware/tegra/ivc.c index a01461d..00de793 100644 --- a/drivers/firmware/tegra/ivc.c +++ b/drivers/firmware/tegra/ivc.c @@ -99,11 +99,11 @@ static inline bool tegra_ivc_empty(struct tegra_ivc *ivc, { /* * This function performs multiple checks on the same values with - * security implications, so create snapshots with ACCESS_ONCE() to + * security implications, so create snapshots with READ_ONCE() to * ensure that these checks use the same values. */ - u32 tx = ACCESS_ONCE(header->tx.count); - u32 rx = ACCESS_ONCE(header->rx.count); + u32 tx = READ_ONCE(header->tx.count); + u32 rx = READ_ONCE(header->rx.count); /* * Perform an over-full check to prevent denial of service attacks @@ -124,8 +124,8 @@ static inline bool tegra_ivc_empty(struct tegra_ivc *ivc, static inline bool tegra_ivc_full(struct tegra_ivc *ivc, struct tegra_ivc_header *header) { - u32 tx = ACCESS_ONCE(header->tx.count); - u32 rx = ACCESS_ONCE(header->rx.count); + u32 tx = READ_ONCE(header->tx.count); + u32 rx = READ_ONCE(header->rx.count); /* * Invalid cases where the counters indicate that the queue is over @@ -137,8 +137,8 @@ static inline bool tegra_ivc_full(struct tegra_ivc *ivc, static inline u32 tegra_ivc_available(struct tegra_ivc *ivc, struct tegra_ivc_header *header) { - u32 tx = ACCESS_ONCE(header->tx.count); - u32 rx = ACCESS_ONCE(header->rx.count); + u32 tx = READ_ONCE(header->tx.count); + u32 rx = READ_ONCE(header->rx.count); /* * This function isn't expected to be used in scenarios where an @@ -151,8 +151,8 @@ static inline u32 tegra_ivc_available(struct tegra_ivc *ivc, static inline void tegra_ivc_advance_tx(struct tegra_ivc *ivc) { - ACCESS_ONCE(ivc->tx.channel->tx.count) = - ACCESS_ONCE(ivc->tx.channel->tx.count) + 1; + WRITE_ONCE(ivc->tx.channel->tx.count, + READ_ONCE(ivc->tx.channel->tx.count) + 1); if (ivc->tx.position == ivc->num_frames - 1) ivc->tx.position = 0; @@ -162,8 +162,8 @@ static inline void tegra_ivc_advance_tx(struct tegra_ivc *ivc) static inline void tegra_ivc_advance_rx(struct tegra_ivc *ivc) { - ACCESS_ONCE(ivc->rx.channel->rx.count) = - ACCESS_ONCE(ivc->rx.channel->rx.count) + 1; + WRITE_ONCE(ivc->rx.channel->rx.count, + READ_ONCE(ivc->rx.channel->rx.count) + 1); if (ivc->rx.position == ivc->num_frames - 1) ivc->rx.position = 0; @@ -428,7 +428,7 @@ int tegra_ivc_notified(struct tegra_ivc *ivc) /* Copy the receiver's state out of shared memory. */ tegra_ivc_invalidate(ivc, ivc->rx.phys + offset); - state = ACCESS_ONCE(ivc->rx.channel->tx.state); + state = READ_ONCE(ivc->rx.channel->tx.state); if (state == TEGRA_IVC_STATE_SYNC) { offset = offsetof(struct tegra_ivc_header, tx.count);