2008-06-13 Joel Sherrill <joel.sherrill@oarcorp.com>

	* posix/include/rtems/posix/pthread.h, posix/src/pthread.c,
	posix/src/pthreadcreate.c, rtems/include/rtems.h, rtems/src/attr.c,
	sapi/include/confdefs.h, sapi/include/rtems/config.h,
	score/inline/rtems/score/stack.inl, score/src/isr.c,
	score/src/mpci.c, score/src/threadcreateidle.c,
	score/src/threadinitialize.c, score/src/threadstackallocate.c: Add
	ability for application to configure minimum stack size. Add
	RTEMS_CONFIGURED_MINIMUM_STACK_SIZE constant so user can clearly
	indicate they want the configured as opposed to the recommended
	minimum stack size.

3 files changed, 22 insertions, 7 deletions

diff --git a/cpukit/posix/include/rtems/posix/pthread.h b/cpukit/posix/include/rtems/posix/pthread.h
index 6d0c739f0c..14eaf36c4c 100644
--- a/cpukit/posix/include/rtems/posix/pthread.h
+++ b/cpukit/posix/include/rtems/posix/pthread.h
@@ -27,9 +27,12 @@ extern "C" {
 #include <rtems/posix/config.h>
 #include <rtems/posix/threadsup.h>
 
-#define PTHREAD_MINIMUM_STACK_SIZE (STACK_MINIMUM_SIZE * 2)
+/**
+ *  The following sets the minimum stack size for POSIX threads.
+ */
+#define PTHREAD_MINIMUM_STACK_SIZE (_Stack_Minimum() * 2)
 
-/*
+/**
  *  The following defines the information control block used to manage
  *  this class of objects.
  */
diff --git a/cpukit/posix/src/pthread.c b/cpukit/posix/src/pthread.c
index 53126e2428..a19e2c069c 100644
--- a/cpukit/posix/src/pthread.c
+++ b/cpukit/posix/src/pthread.c
@@ -44,7 +44,7 @@
 const pthread_attr_t _POSIX_Threads_Default_attributes = {
   TRUE,                       /* is_initialized */
   NULL,                       /* stackaddr */
-  PTHREAD_MINIMUM_STACK_SIZE, /* stacksize */
+  0,                          /* stacksize -- will be adjusted to minimum */
   PTHREAD_SCOPE_PROCESS,      /* contentionscope */
   PTHREAD_INHERIT_SCHED,      /* inheritsched */
   SCHED_FIFO,                 /* schedpolicy */
diff --git a/cpukit/posix/src/pthreadcreate.c b/cpukit/posix/src/pthreadcreate.c
index 6eeda2da14..c579fb3e14 100644
--- a/cpukit/posix/src/pthreadcreate.c
+++ b/cpukit/posix/src/pthreadcreate.c
@@ -26,6 +26,16 @@
 #include <rtems/posix/time.h>
 #include <rtems/score/apimutex.h>
 
+static inline size_t _POSIX_Threads_Ensure_minimum_stack (
+  size_t size
+)
+{
+  if ( size >= PTHREAD_MINIMUM_STACK_SIZE )
+    return size;
+  return PTHREAD_MINIMUM_STACK_SIZE;
+}
+
+
 int pthread_create(
   pthread_t              *thread,
   const pthread_attr_t   *attr,
@@ -54,11 +64,13 @@ int pthread_create(
     return EINVAL;
 
   /*
-   *  Core Thread Initialize insures we get the minimum amount of
+   *  Core Thread Initialize ensures we get the minimum amount of
    *  stack space if it is allowed to allocate it itself.
+   *
+   *  NOTE: If the user provides the stack we will let it drop below
+   *        twice the minimum.
    */
-
-  if ( the_attr->stackaddr && !_Stack_Is_enough( the_attr->stacksize ) )
+  if ( the_attr->stackaddr && !_Stack_Is_enough(the_attr->stacksize) )
     return EINVAL;
 
 #if 0
@@ -184,7 +196,7 @@ int pthread_create(
     &_POSIX_Threads_Information,
     the_thread,
     the_attr->stackaddr,
-    the_attr->stacksize,
+    _POSIX_Threads_Ensure_minimum_stack(the_attr->stacksize),
     is_fp,
     core_priority,
     TRUE,                 /* preemptible */