linux/drivers/counter, branch v5.16-rc1

counter: Fix use-after-free race condition for events_queue_size write

2021-10-21T11:02:47Z

A race condition is possible when writing to events_queue_size where the events kfifo is freed during the execution of a kfifo_in(), resulting in a use-after-free. This patch prevents such a scenario by protecting the events queue in operation with a spinlock and locking before performing the events queue size adjustment. The existing events_lock mutex is renamed to events_out_lock to reflect that it only protects events queue out operations. Because the events queue in operations can occur in an interrupt context, a new events_in_lock spinlock is introduced and utilized. Fixes: feff17a550c7 ("counter: Implement events_queue_size sysfs attribute") Cc: David Lechner Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/20211021103540.955639-1-vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman

counter: Cleanup lingering atomic.h includes

2021-10-21T11:02:45Z

With the removal of the chrdev_lock atomic flag, the counter-sysfs.c and counter-chrdev.c no longer needs to include the atomic.h header file. Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/20211021103514.955622-1-vilhelm.gray@gmail.com Signed-off-by: Greg Kroah-Hartman

counter: drop chrdev_lock

2021-10-19T09:36:28Z

This removes the chrdev_lock from the counter subsystem. This was intended to prevent opening the chrdev more than once. However, this doesn't work in practice since userspace can duplicate file descriptors and pass file descriptors to other processes. Since this protection can't be relied on, it is best to just remove it. Suggested-by: Greg KH Acked-by: William Breathitt Gray Signed-off-by: David Lechner Link: https://lore.kernel.org/r/20211017185521.3468640-1-david@lechnology.com Signed-off-by: Greg Kroah-Hartman

counter/counter-sysfs: use sysfs_emit everywhere

2021-10-19T07:40:49Z

In the counter subsystem, we are already using sysfs_emit(), but there were a few places where we were still using sprintf() in *_show() functions. For consistency and added protections, use sysfs_emit() everywhere. Suggested-by: Greg KH Acked-by: William Breathitt Gray Signed-off-by: David Lechner Link: https://lore.kernel.org/r/20211017190106.3472645-1-david@lechnology.com Signed-off-by: Greg Kroah-Hartman

counter: microchip-tcb-capture: Tidy up a false kernel-doc /** marking.

2021-10-17T09:56:31Z

Deals with W=1 warning This comment starts with '/**', but isn't a kernel-doc comment. Signed-off-by: Jonathan Cameron Cc: Kamel Bouhara Cc: William Breathitt Gray Acked-by: William Breathitt Gray Link: https://lore.kernel.org/r/20210930170347.101153-1-jic23@kernel.org

counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8

2021-10-17T09:55:55Z

The LSI/CSI LS7266R1 chip provides programmable output via the FLG pins. When interrupts are enabled on the ACCES 104-QUAD-8, they occur whenever FLG1 is active. Four functions are available for the FLG1 signal: Carry, Compare, Carry-Borrow, and Index. Carry: Interrupt generated on active low Carry signal. Carry signal toggles every time the respective channel's counter overflows. Compare: Interrupt generated on active low Compare signal. Compare signal toggles every time respective channel's preset register is equal to the respective channel's counter. Carry-Borrow: Interrupt generated on active low Carry signal and active low Borrow signal. Carry signal toggles every time the respective channel's counter overflows. Borrow signal toggles every time the respective channel's counter underflows. Index: Interrupt generated on active high Index signal. These four functions correspond respectivefly to the following four Counter event types: COUNTER_EVENT_OVERFLOW, COUNTER_EVENT_THRESHOLD, COUNTER_EVENT_OVERFLOW_UNDERFLOW, and COUNTER_EVENT_INDEX. Interrupts push Counter events to event channel X, where 'X' is the respective channel whose FLG1 activated. This patch adds IRQ support for the ACCES 104-QUAD-8. The interrupt line numbers for the devices may be configured via the irq array module parameter. Acked-by: Syed Nayyar Waris Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/e3a28e100840e3a336fa93fce77445f0e9d9a674.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron

counter: 104-quad-8: Replace mutex with spinlock

2021-10-17T09:55:43Z

This patch replaces the mutex I/O lock with a spinlock. This is in preparation for a subsequent patch adding IRQ support for 104-QUAD-8 devices; we can't sleep in an interrupt context, so we'll need to use a spinlock instead. Acked-by: Syed Nayyar Waris Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/3f74491dec66de10d062978bcb7b9c2b3bdea86c.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron

counter: Implement events_queue_size sysfs attribute

2021-10-17T09:55:01Z

The events_queue_size sysfs attribute provides a way for users to dynamically configure the Counter events queue size for the Counter character device interface. The size is in number of struct counter_event data structures. The number of elements will be rounded-up to a power of 2 due to a requirement of the kfifo_alloc function called during reallocation of the queue. Cc: Oleksij Rempel Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/c914b2db2ea0a2637633bcc3e86ded3c94783f2e.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron

counter: Implement *_component_id sysfs attributes

2021-10-17T09:54:48Z

The Generic Counter chrdev interface expects users to supply component IDs in order to select extensions for requests. In order for users to know what component ID belongs to which extension this information must be exposed. The *_component_id attribute provides a way for users to discover what component ID belongs to which respective extension. Cc: David Lechner Cc: Gwendal Grignou Cc: Dan Carpenter Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/8961a11edbb882fc689e468194f5be75f572443e.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron

counter: Implement signalZ_action_component_id sysfs attribute

2021-10-17T09:54:36Z

The Generic Counter chrdev interface expects users to supply component IDs in order to select Synapses for requests. In order for users to know what component ID belongs to which Synapse this information must be exposed. The signalZ_action_component_id attribute provides a way for users to discover what component ID belongs to the respective Synapse. Cc: Gwendal Grignou Cc: Dan Carpenter Reviewed-by: David Lechner Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/a6c81b2f1f5d0b8d59b1ebe4f0fed04914b07547.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron