[PATCH] realtek: don't unmask non-maskable GPIO IRQs

[Robert Marko]

On Sun, 29 May 2022 at 19:49, Sander Vanheule <sander at svanheule.net> wrote:
>
> On uniprocessor builds, for_each_cpu(cpu, mask) will assume 'mask'
> always contains exactly one CPU, and ignore the actual mask contents.
> This causes the loop to run, even when it shouldn't on an empty mask,
> and tries to access an unintialised pointer.
>
> Fix this by wrapping the loop in a cpumask_empty() check, to ensure it
> will not run on uniprocessor builds if the CPU mask is empty.
>
> Fixes: af6cd37f42f3 ("realtek: replace RTL93xx GPIO patches")
> Reported-by: Robert Marko <robimarko at gmail.com>
> Reported-by: INAGAKI Hiroshi <musashino.open at gmail.com>
> Signed-off-by: Sander Vanheule <sander at svanheule.net>

Works on DGS-1210-28P, so:
Tested-by: Robert Marko <robimarko at gmail.com>

Regards,
Robert
> ---
>  .../316-otto-gpio-uniprocessor-irq-mask.patch | 29 +++++++++++++++++++
>  1 file changed, 29 insertions(+)
>  create mode 100644 target/linux/realtek/patches-5.10/316-otto-gpio-uniprocessor-irq-mask.patch
>
> diff --git a/target/linux/realtek/patches-5.10/316-otto-gpio-uniprocessor-irq-mask.patch b/target/linux/realtek/patches-5.10/316-otto-gpio-uniprocessor-irq-mask.patch
> new file mode 100644
> index 000000000000..f83f5a781f74
> --- /dev/null
> +++ b/target/linux/realtek/patches-5.10/316-otto-gpio-uniprocessor-irq-mask.patch
> @@ -0,0 +1,29 @@
> +--- a/drivers/gpio/gpio-realtek-otto.c
> ++++ b/drivers/gpio/gpio-realtek-otto.c
> +@@ -304,6 +304,7 @@ static int realtek_gpio_irq_set_affinity
> + static int realtek_gpio_irq_init(struct gpio_chip *gc)
> + {
> +       struct realtek_gpio_ctrl *ctrl = gpiochip_get_data(gc);
> ++      void __iomem *irq_cpu_mask;
> +       unsigned int port;
> +       int cpu;
> +
> +@@ -311,8 +312,16 @@ static int realtek_gpio_irq_init(struct
> +               realtek_gpio_write_imr(ctrl, port, 0, 0);
> +               realtek_gpio_clear_isr(ctrl, port, GENMASK(7, 0));
> +
> +-              for_each_cpu(cpu, &ctrl->cpu_irq_maskable)
> +-                      iowrite8(GENMASK(7, 0), realtek_gpio_irq_cpu_mask(ctrl, port, cpu));
> ++              /*
> ++               * Uniprocessor builds assume a mask always contains one CPU,
> ++               * so only start the loop if we have at least one maskable CPU.
> ++               */
> ++              if(!cpumask_empty(&ctrl->cpu_irq_maskable)) {
> ++                      for_each_cpu(cpu, &ctrl->cpu_irq_maskable) {
> ++                              irq_cpu_mask = realtek_gpio_irq_cpu_mask(ctrl, port, cpu);
> ++                              iowrite8(GENMASK(7, 0), irq_cpu_mask);
> ++                      }
> ++        }
> +       }
> +
> +       return 0;
> --
> 2.36.1
>