eintr: support for blocking syscall INTR (interrupted) mode #13
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pthierry-ledger
added
bug
support EINTR for early awokened sleep
fvalette-ledger
approved these changes
Aug 7, 2024
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When sys_waitforevent() task is preempted due to no input read, the syscall is interrupted.
In that very case, if another task push an IPC and awake the target task, the uapi implementation is continuing its execution just after the effective svc() call, but has not read effective data (due to previous preemption when nothing was read).
In that very case, the waitforevent() uapi implementation must detect such interruption in order to read back the content now that the peer send_ipc() is made.
To do that, a STATUS_INTR (interrupted sycall) has been added, so that the uapi is able to re-execute the sysgate.
This allows fully transparent and homogeneous behavior of waitforevent() whatever the sequential task execution is.
STATUS_INTR has also been added for signal and irq input events, for the very same reason.
For the sleep() case, EINTR is also added for early awoking from sleep() mode, to easily differenciate such case from timeouted sleep, in replacement of the STATUS_OK status code.