gpio: davinci: Validate the obtained number of IRQs

BugLink: https://bugs.launchpad.net/bugs/2073765

[ Upstream commit 7aa9b96e9a73e4ec1771492d0527bd5fc5ef9164 ]

Value of pdata->gpio_unbanked is taken from Device Tree. In case of broken
DT due to any error this value can be any. Without this value validation
there can be out of chips->irqs array boundaries access in
davinci_gpio_probe().

Validate the obtained nirq value so that it won't exceed the maximum
number of IRQs per bank.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: eb3744a ("gpio: davinci: Do not assume continuous IRQ numbering")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Link: https://lore.kernel.org/r/20240618144344.16943-1-amishin@t-argos.ru
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Portia Stephens <portia.stephens@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

Author: Aleksandr Mishin

drivers/gpio/gpio-davinci.c

@@ -227,6 +227,11 @@ static int davinci_gpio_probe(struct platform_device *pdev)
 	else
 		nirq = DIV_ROUND_UP(ngpio, 16);
 
+	if (nirq > MAX_INT_PER_BANK) {
+		dev_err(dev, "Too many IRQs!\n");
+		return -EINVAL;
+	}
+
 	chips = devm_kzalloc(dev, sizeof(*chips), GFP_KERNEL);
 	if (!chips)
 		return -ENOMEM;