forked from Imagelibrary/rtems
254b445071
GNU autoconf. This is the first large step in allowing an RTEMS user to perform a one-tree build (per crossgcc FAQ) including RTEMS in the build process. With this change RTEMS is configured in built in the same style as the GNU tools, yet retains the basic structure of its traditional Makefiles (ala Tony Bennett). Jiri Gaisler (jgais@wd.estec.esa.nl) deserves (and received) a big thank you for doing this. There are still issues to be resolved but as of this commit, all target which can be built on a linux host have been using a modified version of the source Jiri submitted. This source was merged and most targets built in the tree before this commit. There are some issues which remain to be resolved but they are primarily related to host OS dependencies, script issues, the use of gawk for hack_specs, and the dependence on gcc snapshots. These will be resolved.
#
# $Id$
#
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.