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wake up user space thread from kernel space ISR

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Old 06-03-2009
wake up user space thread from kernel space ISR
Hello, I'm searching for a proper way to let the kernel space ISR(implemented in a kernel module) wake up a user space thread on a hardware interrupt.

Except for sending a real-time signal, is it possible to use a semaphore?

I've searched it on google, but it seems impossible to share a semaphore between user space and kernel space in common linux. Only some real-timer linux versions like RTAI provides a set of private API to inter-operate a semaphore between kernel and user space.

And there is no header file of Posix or SystemV semaphore APIs in linux kernel source, either.

So I wonder whether it is possible to do it via a semaphore ? Or is it a better way to use netlink?

Thank you in advance !
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LEARN ABOUT DEBIAN

switchtest

SWITCHTEST(1)							      Xenomai							     SWITCHTEST(1)

NAME

       switchtest - Xenomai context switch test

SYNOPSIS

       switchtest [options] threadspec threadspec...

DESCRIPTION

       switchtest  is part of Xenomai. It can be used to test thread context switches. switchtest creates threads of various types and attempts to
       switch context between these threads, printing the count of context switches every second. A  suitable  Xenomai	enabled  kernel  with  the
       respective module (xeno_posix) must be installed.

OPTIONS

       Each threadspec specifies the characteristics of a thread to be created:

       threadspec = (rtk|rtup|rtus|rtuo)(_fp|_ufpp|_ufps)*[0-9]*

       rtk for a kernel-space real-time thread

       rtup for a user-space real-time thread running in primary mode

       rtus for a user-space real-time thread running in secondary mode

       rtuo for a user-space real-time thread oscillating between primary and secondary mode

       _fp means that the created thread will have the XNFPU bit armed (only valid for rtk)

       _ufpp means that the created thread will use the FPU when in primary mode0valid for rtus)

       _ufps means that the created thread will use the FPU when in secondary mode (invalid for rtk and rtup)

       [0-9]* specifies the ID of the CPU where the created thread will run, 0 if unspecified

       Passing no threadspec is equivalent to running:

       switchtest  rtkN  rtkN  rtk_fpN rtk_fpN rtk_fp_ufppN rtk_fp_ufppN rtupN rtupN rtup_ufppN rtup_ufppN rtusN rtusN rtus_ufpsN rtus_ufpsN rtuoN
       rtuoN rtuo_ufppN rtuo_ufppN rtuo_ufpsN rtuo_ufpsN rtuo_ufpp_ufpsN rtuo_ufpp_ufpsN

       with N=1,...,nr_cpus, i.e. occurrences of all the arguments for each CPU

       Passing only the --nofpu or -n argument is equivalent to running:

       switchtest rtkN rtkN rtupN rtupN rtusN rtusN rtuoN rtuoN

       similar to the above.

       switchtest accepts the following options:

       --help, -h
	      print usage information and exit

       --lines <lines>, -l <lines>
	      print headers every <lines> lines

       --quiet or -q
	      prevent this program from printing every second the count of ncontext switches

       --timeout <duration>, -T <duration>
	      limit the test duration to <duration> seconds

       --nofpu, -n
	      disables any use of FPU instructions

AUTHOR

       switchtest was written by Philippe Gerum <rpm@xenomai.org> and Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>. This man  page  was
       written by Roland Stigge <stigge@antcom.de>.

2.6.0								    2008-04-19							     SWITCHTEST(1)