[PATCH 10/10] pinctrl: qcom: Check qcom_scm_io_readl() return value in msm_gpio_irq_set_type()

[Lee Jones <lee@kernel.org>]

In msm_gpio_irq_set_type(), when pctrl->intr_target_use_scm is set, the
return value of qcom_scm_io_readl(addr, &val) is ignored.  If the SCM read
fails, val remains uninitialised and its stack contents are modified and
written back to the hardware register via qcom_scm_io_writel().

Check the return value of qcom_scm_io_readl() before modifying and writing
back val.

Fixes: 13bec8d49bdf ("pinctrl: qcom: use scm_call to route GPIO irq to Apps")
Closes: https://sashiko.dev/#/bug/linux-a5545ffd-48cc-4856-94cc-4b2dd7968f50
Cc: stable@vger.kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 27f06bbc113c..1b46735fc4bc 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -1105,11 +1105,13 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 		u32 addr = pctrl->phys_base[0] + reg;
 		int ret;
 
-		qcom_scm_io_readl(addr, &val);
-		val &= ~(intr_target_mask << g->intr_target_bit);
-		val |= g->intr_target_kpss_val << g->intr_target_bit;
+		ret = qcom_scm_io_readl(addr, &val);
+		if (!ret) {
+			val &= ~(intr_target_mask << g->intr_target_bit);
+			val |= g->intr_target_kpss_val << g->intr_target_bit;
 
-		ret = qcom_scm_io_writel(addr, val);
+			ret = qcom_scm_io_writel(addr, val);
+		}
 		if (ret)
 			dev_err(pctrl->dev,
 				"Failed routing %lu interrupt to Apps proc",
-- 
2.56.0.385.gac671c819a-goog