linux.git/drivers/gpio/gpiolib-cdev.c, branch v6.7

gpiolib: cdev: add gpio_device locking wrapper around gpio_ioctl()

2023-12-21T09:27:07+00:00

While the GPIO cdev gpio_ioctl() call is in progress, the kernel can
call gpiochip_remove() which will set gdev->chip to NULL, after which
any subsequent access will cause a crash.

gpio_ioctl() was overlooked by the previous fix to protect syscalls
(bdbbae241a04), so add protection for that.

Fixes: bdbbae241a04 ("gpiolib: protect the GPIO device against being dropped while in use by user-space")
Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Signed-off-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

treewide: rename pinctrl_gpio_can_use_line_new()

2023-11-04T09:23:21+00:00

Now that pinctrl_gpio_can_use_line() is no longer used, let's drop the
'_new' suffix from its improved variant.

Signed-off-by: Bartosz Golaszewski 
Acked-by: Linus Walleij

gpio: cdev: use pinctrl_gpio_can_use_line_new()

2023-11-04T09:23:18+00:00

Use the improved variant of pinctrl_gpio_can_use_line() which takes a
pointer to the gpio_chip and a controller-relative offset.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Andy Shevchenko 
Acked-by: Linus Walleij

gpiolib: cdev: annotate struct linereq with __counted_by

2023-09-25T07:42:23+00:00

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct linereq.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Signed-off-by: Kees Cook 
Reviewed-by: Gustavo A. R. Silva 
Reviewed-by: Linus Walleij 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Bartosz Golaszewski

gpiolib: provide and use gpiod_line_state_notify()

2023-08-22T07:37:46+00:00

Wrap the calls to blocking_notifier_call_chain() for the line state
notifier with a helper that allows us to use fewer lines of code and
simpler syntax.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Andy Shevchenko

gpio: cdev: wake up lineevent poll() on device unbind

2023-08-21T13:57:05+00:00

Add a notifier block to the lineevent_state structure and register it
with the gpio_device's device notifier. Upon reception of an event, wake
up the wait queue so that the user-space be forced out of poll() and
need to go into a new system call which will then fail due to the chip
being gone.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Linus Walleij 
Reviewed-by: Kent Gibson

gpio: cdev: wake up linereq poll() on device unbind

2023-08-21T13:57:05+00:00

Add a notifier block to the linereq structure and register it with the
gpio_device's device notifier. Upon reception of an event, wake up the
wait queue so that the user-space be forced out of poll() and need to go
into a new system call which will then fail due to the chip being gone.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Linus Walleij 
Reviewed-by: Kent Gibson

gpio: cdev: wake up chardev poll() on device unbind

2023-08-21T13:57:05+00:00

Add a notifier block to the gpio_chardev_data structure and register it
with the gpio_device's device notifier. Upon reception of an event, wake
up the wait queue so that the user-space be forced out of poll() and need
to go into a new system call which will then fail due to the chip being
gone.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Linus Walleij 
Reviewed-by: Kent Gibson

gpiolib: add a second blocking notifier to struct gpio_device

2023-08-21T13:57:05+00:00

Add a new blocking notifier to struct gpio_device and use it to notify
subscribers about the GPIO device being unregistered from the device
model.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Linus Walleij 
Reviewed-by: Kent Gibson

gpio: cdev: open-code to_gpio_chardev_data()

2023-08-21T13:57:05+00:00

This function is a wrapper around container_of(). It's used only once and
we will have a second notifier soon, so instead of having two flavors of
this helper, let's just open-code where needed.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Linus Walleij 
Reviewed-by: Kent Gibson