Files
rtems/cpukit/libmisc/cpuuse
Joel Sherrill 9608320702 Patch rtems-rc-19991117-4.diff from Ralf Corsepius <corsepiu@faw.uni-ulm.de>:
.. a major configuration cleanup
    ... major enhancement of automake support.

    ... and it contains a *major*  breakthough:

    Automake support for libchip and libmisc *LEAF* directories.

    To implement this I have used several nasty tricks
        * The basical trick is to wrap an old Makefile.in's contents into a
          Makefile.am and still continue to use (i.e include) the old
          *.cfg files.

        * Replaced each INSTALL_IF_CHANGE and INSTALL_VARIANT with make
          dependencies
        * Add a gnu-make ifdef AUTOMAKE to main.cfg to avoid conflicts between
          automake and RTEMS make rules
        * Replaced each install:: and preinstall:: rule with make dependencies
        * Replaced SUB_DIRS with SUBDIRS in all Makefile.ins (Automake
          convention)
        * Removed each manually added autoconf substitution which automake
          performs automatically.

    This is not yet full automake support, because using the temporary
    installation directory, preinstallation in general and building variants
    are in contradiction to automake's basic working principles ...

    ... the new Makefile.ams work still somewhat clumsy
    ... nevertheless they work (quite well).

    WARNING:

    At first glance this patch is small, but
        * it affects the whole configuration system.
        * it opens the road to introducing automake to all Makefile.ins
          currently not being under automake control.

    JOEL> Does this remove or add any files?

    Both, all Makefile.ins below libchip and libmisc get replaced with
    Makefile.ams.
1999-11-22 13:41:11 +00:00
..
1999-11-17 17:51:34 +00:00
1999-11-17 17:51:34 +00:00

#
#  $Id$
#

This directory contains a stack bounds checker.  It provides two
primary features:

   + check for stack overflow at each context switch
   + provides an educated guess at each task's stack usage

The stack overflow check at context switch works by looking for
a 16 byte pattern at the logical end of the stack to be corrupted.
The "guesser" assumes that the entire stack was prefilled with a known
pattern and assumes that the pattern is still in place if the memory
has not been used as a stack.

Both of these can be fooled by pushing large holes onto the stack
and not writing to them... or (much more unlikely) writing the
magic patterns into memory.

This code has not been extensively tested.  It is provided as a tool
for RTEMS users to catch the most common mistake in multitasking
systems ... too little stack space.  Suggestions and comments are appreciated.

NOTES:

1.  Stack usage information is questionable on CPUs which push
    large holes on stack.

2.  The stack checker has a tendency to generate a fault when
    trying to print the helpful diagnostic message.  If it comes
    out, congratulations. If not, then the variable Stack_check_Blown_task
    contains a pointer to the TCB of the offending task.  This
    is usually enough to go on.

FUTURE:

1.  Determine how/if gcc will generate stack probe calls and support that.

2.  Get accurate stack usage numbers on i960.. it pushes very large
    holes on the stack.