forked from Imagelibrary/rtems
236b701440
PR 408/filesystem * cpuuse/cpuuse.c: Added sync() service. As part of adding this service, the new RTEMS service rtems_iterate_over_all_threads() was also added. This new service makes it easier to iterate over all the tasks/threads in a system and perform an action on them. This change is to use the new thread iteration service.
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# $Id$
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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.