[SRU][J:linux-bluefield][PATCH v1 1/1] UBUNTU: SAUCE: gpio-mlxbf3: support valid mask

[Tim Gardner]

On 10/9/23 4:29 PM, Asmaa Mnebhi wrote:
> BugLink: https://bugs.launchpad.net/bugs/2038868
> 
> After syncing up the gpio-mlxbf3.c driver with the upstreamed version,
> we dropped the use of the valid_mask variable because kernels greater
> or equal to 6.2.0 don't need it.
> This is no longer needed in kernel versions >= 6.2.0 because valid_mask
> is populated by core gpio code.
> 5.15 kernel, doesn't support that feature so we still need to explicitly
> define valid_mask as we did before.
> This doesnt impact the functionality of the GPIO driver but it is a
> security breach as it doesnt restrict the access to gpios defined in the
> acpi table by valid_mask.
> 
> Signed-off-by: Asmaa Mnebhi <asmaa at nvidia.com>
> ---
>   drivers/gpio/gpio-mlxbf3.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-mlxbf3.c b/drivers/gpio/gpio-mlxbf3.c
> index e63b0e7e90bd..e1375756c487 100644
> --- a/drivers/gpio/gpio-mlxbf3.c
> +++ b/drivers/gpio/gpio-mlxbf3.c
> @@ -49,6 +49,9 @@ struct mlxbf3_gpio_context {
>   
>   	/* YU GPIO cause block address */
>   	void __iomem *gpio_cause_io;
> +
> +	/* Mask of valid gpios that can be accessed by software */
> +	unsigned int valid_mask;
>   };
>   
>   static void mlxbf3_gpio_irq_enable(struct irq_data *irqd)
> @@ -150,6 +153,17 @@ static void mlxbf3_gpio_irq_ack(struct irq_data *data)
>   {
>   }
>   
> +static int mlxbf3_gpio_init_valid_mask(struct gpio_chip *gc,
> +				       unsigned long *valid_mask,
> +				       unsigned int ngpios)
> +{
> +	struct mlxbf3_gpio_context *gs = gpiochip_get_data(gc);
> +
> +	*valid_mask = gs->valid_mask;
> +
> +	return 0;
> +}
> +
>   static struct irq_chip gpio_mlxbf3_irqchip = {
>   	.name = "MLNXBF33",
>   	.irq_ack = mlxbf3_gpio_irq_ack,
> @@ -205,6 +219,10 @@ static int mlxbf3_gpio_probe(struct platform_device *pdev)
>   	gs->gpio_clr_io = devm_platform_ioremap_resource(pdev, 3);
>   	if (IS_ERR(gs->gpio_clr_io))
>   		return PTR_ERR(gs->gpio_clr_io);
> +
> +	gs->valid_mask = 0x0;

Isn't this ^ superfluous ? It appears that gs->valid_mask is overwritten 
in the call to device_property_read_u32().

> +	        device_property_read_u32(dev, "valid_mask", &gs->valid_mask);
> +
>   	gc = &gs->gc;
>   
>   	ret = bgpio_init(gc, dev, 4,
> @@ -218,6 +236,7 @@ static int mlxbf3_gpio_probe(struct platform_device *pdev)
>   	gc->free = gpiochip_generic_free;
>   	gc->owner = THIS_MODULE;
>   	gc->add_pin_ranges = mlxbf3_gpio_add_pin_ranges;
> +	gc->init_valid_mask = mlxbf3_gpio_init_valid_mask;
>   
>   	irq = platform_get_irq(pdev, 0);
>   	if (irq >= 0) {

-- 
-----------
Tim Gardner
Canonical, Inc