2007-05-10 Joel Sherrill <joel.sherrill@OARcorp.com>

	PR 1237/rtems
	* cpu.c, cpu_asm.S, rtems/score/cpu.h: Add logic to prevent stack creep
	when interrupts occur at a sufficient rate that the interrupted
	thread never gets to clean its stack. This patch ensures that an
	interrupted thread will not nest ISR dispatches on its stack.

1 files changed, 13 insertions, 0 deletions

diff --git a/cpukit/score/cpu/sparc/cpu.c b/cpukit/score/cpu/sparc/cpu.c
index ed240fc8a8..5e6bf3717d 100644
--- a/cpukit/score/cpu/sparc/cpu.c
+++ b/cpukit/score/cpu/sparc/cpu.c
@@ -71,6 +71,13 @@ void _CPU_Initialize(
    */
 
   _CPU_Table = *cpu_table;
+
+  /*
+   *  Since no tasks have been created yet and no interrupts have occurred,
+   *  there is no way that the currently executing thread can have an
+   *  _ISR_Dispatch stack frame on its stack.
+   */
+  _CPU_ISR_Dispatch_disable = 0;
 }
 
 /*PAGE
@@ -327,4 +334,10 @@ void _CPU_Context_Initialize(
       tmp_psr |= SPARC_PSR_EF_MASK;
 #endif
     the_context->psr = tmp_psr;
+
+  /*
+   *  Since THIS thread is being created, there is no way that THIS
+   *  thread can have an _ISR_Dispatch stack frame on its stack.
+   */
+    the_context->isr_dispatch_disable = 0;
 }