From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4276727AC37; Wed, 9 Jul 2025 08:44:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752050674; cv=none; b=ul6tRQ5qFdaPnoaY6oWPa3BrJOOGnaYTTlYjIsO0Iaa7GyW5u55oHZsM69lDQzNmx6wfYo81Eb9ryUD9jRQFypE+tqt1e/xICdcO29igayCePUiV5N3wmuRiOwTsftZOSNGtEIiffNkFw4Zi/YCEK74FufEBQXD2YXpbzrxt+A4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752050674; c=relaxed/simple; bh=lwQ2KKKmVP54nbs4jel6XWDPyKiP+QppmSbUcd856N0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MygE7F7wjJB2YWgKPYot/dhJtNsLNIAC5gHyQmNLERdgWw9REfO5QYDRtAYcX1WiQcnp+zJc+Poi/KtOnBn5gWvYa0LdIhbw88Tg1/zwa7ph/iaOiv+6ZDoTrlgzj7a7XqhvnCvJ1/91iT0aqDb3WOWXXiJtiSau/v9DYgzOzjA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0meTvm5F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0meTvm5F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C78BC4CEEF; Wed, 9 Jul 2025 08:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752050673; bh=lwQ2KKKmVP54nbs4jel6XWDPyKiP+QppmSbUcd856N0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0meTvm5Fs8Qz7iZrXUC7Pg2gSzJmhZapvoDupt+zSqtOMzeBBZiuzq4gK4NpMlZy2 PT20Y4k9viWa4D6d/Bys4SM6I6X/AGjbplivRy8Xr+QTg+/5JeHz5G28GYFJ+of2KF gh5GTlXCy8LC3R2oojoXOyvA5S6dveG79vBipnxU= Date: Wed, 9 Jul 2025 10:44:29 +0200 From: Greg Kroah-Hartman To: Komal Bajaj Cc: linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Souradeep Chowdhury , Konrad Dybcio Subject: Re: [PATCH v4] usb: misc: qcom_eud: Access EUD_MODE_MANAGER2 through secure calls Message-ID: <2025070924-wilt-dreamt-fb25@gregkh> References: <20250709065533.25724-1-komal.bajaj@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250709065533.25724-1-komal.bajaj@oss.qualcomm.com> On Wed, Jul 09, 2025 at 12:25:14PM +0530, Komal Bajaj wrote: > EUD_MODE_MANAGER2 register is mapped to a memory region that is marked > as read-only for HLOS, enforcing access restrictions that prohibit > direct memory-mapped writes via writel(). > > Attempts to write to this region from HLOS can result in silent failures > or memory access violations, particularly when toggling EUD (Embedded > USB Debugger) state. To ensure secure register access, modify the driver > to use qcom_scm_io_writel(), which routes the write operation to Qualcomm > Secure Channel Monitor (SCM). SCM has the necessary permissions to access > protected memory regions, enabling reliable control over EUD state. > > SC7280, the only user of EUD is also affected, indicating that this could > never have worked on a properly fused device. > > Fixes: 9a1bf58ccd44 ("usb: misc: eud: Add driver support for Embedded USB Debugger(EUD)") > Signed-off-by: Melody Olvera > Signed-off-by: Komal Bajaj > Reviewed-by: Konrad Dybcio > --- > Changes in v4: > * Added error logging in disable_eud() for SCM write failures, per Konrad’s suggestion > * Link to v3: https://lore.kernel.org/all/20250708085208.19089-1-komal.bajaj@oss.qualcomm.com/ > > Changes in v3: > * Moved secure write before normal writes > * Added error checking in disable_eud() > * Use ENOMEM error code if platform_get_resource() fails > * Select QCOM_SCM driver if USB_QCOM_EUD is enabled > * Link to v2: https://lore.kernel.org/all/20250627125131.27606-1-komal.bajaj@oss.qualcomm.com/ > > Changes in v2: > * Drop separate compatible to be added for secure eud > * Use secure call to access EUD mode manager register > * Link to v1: https://lore.kernel.org/all/20240807183205.803847-1-quic_molvera@quicinc.com/ > > drivers/usb/misc/Kconfig | 1 + > drivers/usb/misc/qcom_eud.c | 27 +++++++++++++++++++++------ > 2 files changed, 22 insertions(+), 6 deletions(-) > > diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig > index 6497c4e81e95..f49d5ac0e957 100644 > --- a/drivers/usb/misc/Kconfig > +++ b/drivers/usb/misc/Kconfig > @@ -148,6 +148,7 @@ config USB_QCOM_EUD > tristate "QCOM Embedded USB Debugger(EUD) Driver" > depends on ARCH_QCOM || COMPILE_TEST > select USB_ROLE_SWITCH > + select QCOM_SCM How is this select going to work if COMPILE_TEST is enabled on non-ARCH_QCOM configs? Please don't use select if at all possible, use "depends" properly. > help > This module enables support for Qualcomm Technologies, Inc. > Embedded USB Debugger (EUD). The EUD is a control peripheral > diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c > index 83079c414b4f..a58081f53db3 100644 > --- a/drivers/usb/misc/qcom_eud.c > +++ b/drivers/usb/misc/qcom_eud.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > > #define EUD_REG_INT1_EN_MASK 0x0024 > #define EUD_REG_INT_STATUS_1 0x0044 > @@ -34,7 +35,7 @@ struct eud_chip { > struct device *dev; > struct usb_role_switch *role_sw; > void __iomem *base; > - void __iomem *mode_mgr; > + phys_addr_t mode_mgr; > unsigned int int_status; > int irq; > bool enabled; > @@ -43,18 +44,30 @@ struct eud_chip { > > static int enable_eud(struct eud_chip *priv) > { > + int ret; > + > + ret = qcom_scm_io_writel(priv->mode_mgr + EUD_REG_EUD_EN2, 1); > + if (ret) > + return ret; > + > writel(EUD_ENABLE, priv->base + EUD_REG_CSR_EUD_EN); Nit, why is your local writel() function in backwards order of parameters from qcom_scm_io_writel()? That's going to be a major pain to maintain over time, don't you think? > writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE, > priv->base + EUD_REG_INT1_EN_MASK); > - writel(1, priv->mode_mgr + EUD_REG_EUD_EN2); > > return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE); > } > > static void disable_eud(struct eud_chip *priv) > { > + int ret; > + > + ret = qcom_scm_io_writel(priv->mode_mgr + EUD_REG_EUD_EN2, 0); > + if (ret) { > + dev_err(priv->dev, "failed to disable eud\n"); > + return; > + } > + > writel(0, priv->base + EUD_REG_CSR_EUD_EN); > - writel(0, priv->mode_mgr + EUD_REG_EUD_EN2); > } > > static ssize_t enable_show(struct device *dev, > @@ -178,6 +191,7 @@ static void eud_role_switch_release(void *data) > static int eud_probe(struct platform_device *pdev) > { > struct eud_chip *chip; > + struct resource *res; > int ret; > > chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); > @@ -200,9 +214,10 @@ static int eud_probe(struct platform_device *pdev) > if (IS_ERR(chip->base)) > return PTR_ERR(chip->base); > > - chip->mode_mgr = devm_platform_ioremap_resource(pdev, 1); > - if (IS_ERR(chip->mode_mgr)) > - return PTR_ERR(chip->mode_mgr); > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); > + if (!res) > + return -ENODEV; > + chip->mode_mgr = res->start; No ioremap() call needed anymore? Why not? thanks, greg k-h