optee: ffa: fix sleep in atomic context

Summary

In the Linux kernel, the following vulnerability has been resolved: optee: ffa: fix sleep in atomic context The OP-TEE driver registers the function notif_callback() for FF-A notifications. However, this function is called in an atomic context leading to errors like this when processing asynchronous notifications: | BUG: sleeping function called from invalid context at kernel/locking/mutex.c:258 | in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 9, name: kworker/0:0 | preempt_count: 1, expected: 0 | RCU nest depth: 0, expected: 0 | CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.14.0-00019-g657536ebe0aa #13 | Hardware name: linux,dummy-virt (DT) | Workqueue: ffa_pcpu_irq_notification notif_pcpu_irq_work_fn | Call trace: | show_stack+0x18/0x24 (C) | dump_stack_lvl+0x78/0x90 | dump_stack+0x18/0x24 | __might_resched+0x114/0x170 | __might_sleep+0x48/0x98 | mutex_lock+0x24/0x80 | optee_get_msg_arg+0x7c/0x21c | simple_call_with_arg+0x50/0xc0 | optee_do_bottom_half+0x14/0x20 | notif_callback+0x3c/0x48 | handle_notif_callbacks+0x9c/0xe0 | notif_get_and_handle+0x40/0x88 | generic_exec_single+0x80/0xc0 | smp_call_function_single+0xfc/0x1a0 | notif_pcpu_irq_work_fn+0x2c/0x38 | process_one_work+0x14c/0x2b4 | worker_thread+0x2e4/0x3e0 | kthread+0x13c/0x210 | ret_from_fork+0x10/0x20 Fix this by adding work queue to process the notification in a non-atomic context.