Changeset 1543932 in rtems

Timestamp:

04/24/96 17:36:35 (27 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

11532ca

Parents:

d2d6467

Message:

added comment regarding stack alignment issues to thread stack allocation
routine.

Files:

• c/src/exec/score/src/thread.c (modified) (2 diffs)
• cpukit/score/src/thread.c (modified) (2 diffs)

c/src/exec/score/src/thread.c

@@ -319 +319 @@
    * routine can call the correct deallocation routine.
    */
+
   if ( _CPU_Table.stack_allocate_hook )
   {
     stack_addr = (*_CPU_Table.stack_allocate_hook)( stack_size );
   } else {
+
+    /*
+     *  First pad the requested size so we allocate enough memory
+     *  so the context initialization can align it properly.  The address
+     *  returned the workspace allocate must be directly stored in the
+     *  stack control block because it is later used in the free sequence.
+     *
+     *  Thus it is the responsibility of the CPU dependent code to 
+     *  get and keep the stack adjust factor, the stack alignment, and 
+     *  the context initialization sequence in sync.
+     */
+
     stack_size = _Stack_Adjust_size( stack_size );
     stack_addr = _Workspace_Allocate( stack_size );
@@ -348 +361 @@
      * routine properly matches the allocation of the stack.
      */
+
     if ( _CPU_Table.stack_free_hook )
         (*_CPU_Table.stack_free_hook)( stack_addr );

cpukit/score/src/thread.c

@@ -319 +319 @@
    * routine can call the correct deallocation routine.
    */
+
   if ( _CPU_Table.stack_allocate_hook )
   {
     stack_addr = (*_CPU_Table.stack_allocate_hook)( stack_size );
   } else {
+
+    /*
+     *  First pad the requested size so we allocate enough memory
+     *  so the context initialization can align it properly.  The address
+     *  returned the workspace allocate must be directly stored in the
+     *  stack control block because it is later used in the free sequence.
+     *
+     *  Thus it is the responsibility of the CPU dependent code to 
+     *  get and keep the stack adjust factor, the stack alignment, and 
+     *  the context initialization sequence in sync.
+     */
+
     stack_size = _Stack_Adjust_size( stack_size );
     stack_addr = _Workspace_Allocate( stack_size );
@@ -348 +361 @@
      * routine properly matches the allocation of the stack.
      */
+
     if ( _CPU_Table.stack_free_hook )
         (*_CPU_Table.stack_free_hook)( stack_addr );