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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33409E7C4E8 for ; Wed, 4 Oct 2023 18:03:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243758AbjJDSDt (ORCPT ); Wed, 4 Oct 2023 14:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243763AbjJDSDs (ORCPT ); Wed, 4 Oct 2023 14:03:48 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A00BBC4 for ; Wed, 4 Oct 2023 11:03:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD662C433C7; Wed, 4 Oct 2023 18:03:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696442624; bh=sffHOMQNWgRyKyL9Qt3hFpRu46H95bJjj24r5rZMNJs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EnUUQGBOnsYySljNUSharVnFzS3zf65GDn7k1KRn0eYcN2IpuRaLcXjGplR9fNy10 GDNTzxbJ4XKbkLBlFmoUVQ6SEueCjtnLQdsUgL8QqaBbW6UqMeG9GRrby+uVBIb2lp EtjvWlFn6kYDFOZcz7wd0FQPUaYWNr/pE+E5ieBI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Prashant Malani , Kuppuswamy Sathyanarayanan , Andy Shevchenko , Mika Westerberg , Stephen Boyd , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Hans de Goede , Sasha Levin Subject: [PATCH 5.15 051/183] platform/x86: intel_scu_ipc: Fail IPC send if still busy Date: Wed, 4 Oct 2023 19:54:42 +0200 Message-ID: <20231004175206.088619835@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231004175203.943277832@linuxfoundation.org> References: <20231004175203.943277832@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephen Boyd [ Upstream commit 85e654c9f722853a595fa941dca60c157b707b86 ] It's possible for interrupts to get significantly delayed to the point that callers of intel_scu_ipc_dev_command() and friends can call the function once, hit a timeout, and call it again while the interrupt still hasn't been processed. This driver will get seriously confused if the interrupt is finally processed after the second IPC has been sent with ipc_command(). It won't know which IPC has been completed. This could be quite disastrous if calling code assumes something has happened upon return from intel_scu_ipc_dev_simple_command() when it actually hasn't. Let's avoid this scenario by simply returning -EBUSY in this case. Hopefully higher layers will know to back off or fail gracefully when this happens. It's all highly unlikely anyway, but it's better to be correct here as we have no way to know which IPC the status register is telling us about if we send a second IPC while the previous IPC is still processing. Cc: Prashant Malani Cc: Kuppuswamy Sathyanarayanan Reviewed-by: Andy Shevchenko Reviewed-by: Mika Westerberg Fixes: ed12f295bfd5 ("ipc: Added support for IPC interrupt mode") Signed-off-by: Stephen Boyd Link: https://lore.kernel.org/r/20230913212723.3055315-5-swboyd@chromium.org Reviewed-by: Ilpo Järvinen Reviewed-by: Hans de Goede Signed-off-by: Hans de Goede Signed-off-by: Sasha Levin --- drivers/platform/x86/intel_scu_ipc.c | 40 +++++++++++++++++++--------- 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/drivers/platform/x86/intel_scu_ipc.c b/drivers/platform/x86/intel_scu_ipc.c index dfe010f1ee084..189c5460edd81 100644 --- a/drivers/platform/x86/intel_scu_ipc.c +++ b/drivers/platform/x86/intel_scu_ipc.c @@ -266,6 +266,24 @@ static int intel_scu_ipc_check_status(struct intel_scu_ipc_dev *scu) return scu->irq > 0 ? ipc_wait_for_interrupt(scu) : busy_loop(scu); } +static struct intel_scu_ipc_dev *intel_scu_ipc_get(struct intel_scu_ipc_dev *scu) +{ + u8 status; + + if (!scu) + scu = ipcdev; + if (!scu) + return ERR_PTR(-ENODEV); + + status = ipc_read_status(scu); + if (status & IPC_STATUS_BUSY) { + dev_dbg(&scu->dev, "device is busy\n"); + return ERR_PTR(-EBUSY); + } + + return scu; +} + /* Read/Write power control(PMIC in Langwell, MSIC in PenWell) registers */ static int pwr_reg_rdwr(struct intel_scu_ipc_dev *scu, u16 *addr, u8 *data, u32 count, u32 op, u32 id) @@ -279,11 +297,10 @@ static int pwr_reg_rdwr(struct intel_scu_ipc_dev *scu, u16 *addr, u8 *data, memset(cbuf, 0, sizeof(cbuf)); mutex_lock(&ipclock); - if (!scu) - scu = ipcdev; - if (!scu) { + scu = intel_scu_ipc_get(scu); + if (IS_ERR(scu)) { mutex_unlock(&ipclock); - return -ENODEV; + return PTR_ERR(scu); } for (nc = 0; nc < count; nc++, offset += 2) { @@ -438,12 +455,12 @@ int intel_scu_ipc_dev_simple_command(struct intel_scu_ipc_dev *scu, int cmd, int err; mutex_lock(&ipclock); - if (!scu) - scu = ipcdev; - if (!scu) { + scu = intel_scu_ipc_get(scu); + if (IS_ERR(scu)) { mutex_unlock(&ipclock); - return -ENODEV; + return PTR_ERR(scu); } + cmdval = sub << 12 | cmd; ipc_command(scu, cmdval); err = intel_scu_ipc_check_status(scu); @@ -483,11 +500,10 @@ int intel_scu_ipc_dev_command_with_size(struct intel_scu_ipc_dev *scu, int cmd, return -EINVAL; mutex_lock(&ipclock); - if (!scu) - scu = ipcdev; - if (!scu) { + scu = intel_scu_ipc_get(scu); + if (IS_ERR(scu)) { mutex_unlock(&ipclock); - return -ENODEV; + return PTR_ERR(scu); } memcpy(inbuf, in, inlen); -- 2.40.1