Hi, it's suggested pencils down today and I have still trouble with the interrupt handling.
I have this functionality: - enable/disable interrupts for a partition - register a handler for a partition - partition needs to acknowledge the interrupt before more a send The kernel handler sends the EOI signal to the pic, but interrupts are not opened before either the user space handler is called (iret) or the interrupt handler returns(sti). The transition from kernel to user space is the hacky part. I copy the interrupted context from the kernel to the user stack. Unfortunately, stack offset for the data isn't constant so I insert a magic value to find the beginning of the data. Then I modify the eip to point to the user space handler. The user space handler recovers the vector number and executes the RTEMS interrupt dispatch routine. Afterwards it sends a system call POK_SYSCALL_IRQ_PARTITION_ACK to signal the kernel, to send further clock interrupts. Then it restores the interrupted context and returns to the point of interruption. Well, it doesn't work. When I enable interrupts through the EFLAGS register and return to the user land, the handler isn't executing. Instead another clock interrupt occurs and we are back in the kernel. Although this interrupt should be very fast (no user handler as there was no ack), it still fires and fires and fires and fires .... So the user space handler isn't making any progress. I acknowledge the clock irq (0x0) during the kernel handler, because clock ticks invoke pok_sched() and a descheduling of the current task will result in an unacknowledged interrupt. If I leave the interrupts disabled after the iret the RTEMS C_dispatch_isr is called which doesn't result in a missing handler error, so I think my clock driver works. I am out of ideas by now. Looks this reoccurring interrupt behaviour familiar to someone? Any ideas where it comes from? How to fix it? Cheers, Philipp _______________________________________________ rtems-devel mailing list rtems-devel@rtems.org http://www.rtems.org/mailman/listinfo/rtems-devel
