linux-kernel - [RESEND PATCH] pinctrl: qcom: lpass-lpi: fix concurrent register updates

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20231013145705.219954-1-krzysztof.kozlowski@linaro.org>
Date:   Fri, 13 Oct 2023 16:57:05 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        stable@...r.kernel.org
Subject: [RESEND PATCH] pinctrl: qcom: lpass-lpi: fix concurrent register updates

The Qualcomm LPASS LPI pin controller driver uses one lock for guarding
Read-Modify-Write code for slew rate registers.  However the pin
configuration and muxing registers have exactly the same RMW code but
are not protected.

Pin controller framework does not provide locking here, thus it is
possible to trigger simultaneous change of pin configuration registers
resulting in non-atomic changes.

Protect from concurrent access by re-using the same lock used to cover
the slew rate register.  Using the same lock instead of adding second
one will make more sense, once we add support for newer Qualcomm SoC,
where slew rate is configured in the same register as pin
configuration/muxing.

Fixes: 6e261d1090d6 ("pinctrl: qcom: Add sm8250 lpass lpi pinctrl driver")
Cc: stable@...r.kernel.org
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

---

Added Linus' review. Resending because no one picked up this patch.
---
 drivers/pinctrl/qcom/pinctrl-lpass-lpi.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c b/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c
index abb6f1de230b..9651aed048cf 100644
--- a/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c
+++ b/drivers/pinctrl/qcom/pinctrl-lpass-lpi.c
@@ -32,7 +32,8 @@ struct lpi_pinctrl {
 	char __iomem *tlmm_base;
 	char __iomem *slew_base;
 	struct clk_bulk_data clks[MAX_LPI_NUM_CLKS];
-	struct mutex slew_access_lock;
+	/* Protects from concurrent register updates */
+	struct mutex lock;
 	DECLARE_BITMAP(ever_gpio, MAX_NR_GPIO);
 	const struct lpi_pinctrl_variant_data *data;
 };
@@ -103,6 +104,7 @@ static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
 	if (WARN_ON(i == g->nfuncs))
 		return -EINVAL;
 
+	mutex_lock(&pctrl->lock);
 	val = lpi_gpio_read(pctrl, pin, LPI_GPIO_CFG_REG);
 
 	/*
@@ -128,6 +130,7 @@ static int lpi_gpio_set_mux(struct pinctrl_dev *pctldev, unsigned int function,
 
 	u32p_replace_bits(&val, i, LPI_GPIO_FUNCTION_MASK);
 	lpi_gpio_write(pctrl, pin, LPI_GPIO_CFG_REG, val);
+	mutex_unlock(&pctrl->lock);
 
 	return 0;
 }
@@ -233,14 +236,14 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
 			if (slew_offset == LPI_NO_SLEW)
 				break;
 
-			mutex_lock(&pctrl->slew_access_lock);
+			mutex_lock(&pctrl->lock);
 
 			sval = ioread32(pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);
 			sval &= ~(LPI_SLEW_RATE_MASK << slew_offset);
 			sval |= arg << slew_offset;
 			iowrite32(sval, pctrl->slew_base + LPI_SLEW_RATE_CTL_REG);
 
-			mutex_unlock(&pctrl->slew_access_lock);
+			mutex_unlock(&pctrl->lock);
 			break;
 		default:
 			return -EINVAL;
@@ -256,6 +259,7 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
 		lpi_gpio_write(pctrl, group, LPI_GPIO_VALUE_REG, val);
 	}
 
+	mutex_lock(&pctrl->lock);
 	val = lpi_gpio_read(pctrl, group, LPI_GPIO_CFG_REG);
 
 	u32p_replace_bits(&val, pullup, LPI_GPIO_PULL_MASK);
@@ -264,6 +268,7 @@ static int lpi_config_set(struct pinctrl_dev *pctldev, unsigned int group,
 	u32p_replace_bits(&val, output_enabled, LPI_GPIO_OE_MASK);
 
 	lpi_gpio_write(pctrl, group, LPI_GPIO_CFG_REG, val);
+	mutex_unlock(&pctrl->lock);
 
 	return 0;
 }
@@ -461,7 +466,7 @@ int lpi_pinctrl_probe(struct platform_device *pdev)
 	pctrl->chip.label = dev_name(dev);
 	pctrl->chip.can_sleep = false;
 
-	mutex_init(&pctrl->slew_access_lock);
+	mutex_init(&pctrl->lock);
 
 	pctrl->ctrl = devm_pinctrl_register(dev, &pctrl->desc, pctrl);
 	if (IS_ERR(pctrl->ctrl)) {
@@ -483,7 +488,7 @@ int lpi_pinctrl_probe(struct platform_device *pdev)
 	return 0;
 
 err_pinctrl:
-	mutex_destroy(&pctrl->slew_access_lock);
+	mutex_destroy(&pctrl->lock);
 	clk_bulk_disable_unprepare(MAX_LPI_NUM_CLKS, pctrl->clks);
 
 	return ret;
@@ -495,7 +500,7 @@ void lpi_pinctrl_remove(struct platform_device *pdev)
 	struct lpi_pinctrl *pctrl = platform_get_drvdata(pdev);
 	int i;
 
-	mutex_destroy(&pctrl->slew_access_lock);
+	mutex_destroy(&pctrl->lock);
 	clk_bulk_disable_unprepare(MAX_LPI_NUM_CLKS, pctrl->clks);
 
 	for (i = 0; i < pctrl->data->npins; i++)
-- 
2.34.1