score: Ensure stack alignment requirement

Make sure that a user-provided stack size is the minimum size allocated
for the stack.

Make sure we meet the stack alignment requirement also for CPU ports
with CPU_STACK_ALIGNMENT > CPU_HEAP_ALIGNMENT.

cpukit/include/rtems/score/context.h

@@ -49,8 +49,7 @@ extern "C" {
  */
 #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
   #define CONTEXT_FP_SIZE \
-    ( ( CPU_CONTEXT_FP_SIZE + CPU_HEAP_ALIGNMENT - 1 ) \
-      & ~( CPU_HEAP_ALIGNMENT - 1 ) )
+    RTEMS_ALIGN_UP( CPU_CONTEXT_FP_SIZE, CPU_STACK_ALIGNMENT )
 #else
   #define CONTEXT_FP_SIZE 0
 #endif

cpukit/include/rtems/score/stackimpl.h

@@ -135,6 +135,7 @@ RTEMS_INLINE_ROUTINE size_t _Stack_Extend_size(
 )
 {
   size_t extra_size;
+  size_t alignment_overhead;
 
   extra_size = _TLS_Get_allocation_size();
 
@@ -147,15 +148,32 @@ RTEMS_INLINE_ROUTINE size_t _Stack_Extend_size(
   (void) is_fp;
 #endif
 
-  stack_size += extra_size;
+  /*
+   * In order to make sure that a user-provided stack size is the minimum which
+   * can be allocated for the stack, we have to align it up to the next stack
+   * boundary.
+   */
+  alignment_overhead = CPU_STACK_ALIGNMENT - 1;
 
-  if ( stack_size < extra_size ) {
+#if CPU_STACK_ALIGNMENT > CPU_HEAP_ALIGNMENT
+  /*
+   * If the heap allocator does not meet the stack alignment requirement, then
+   * we have to do the stack alignment manually in _Thread_Initialize() and
+   * need to allocate extra space for this.
+   */
+  alignment_overhead += CPU_STACK_ALIGNMENT - CPU_HEAP_ALIGNMENT;
+#endif
+
+  if ( stack_size > SIZE_MAX - extra_size - alignment_overhead ) {
     /*
      * In case of an unsigned integer overflow, saturate at the maximum value.
      */
-    stack_size = SIZE_MAX;
+    return SIZE_MAX;
   }
 
+  stack_size += extra_size;
+  stack_size = RTEMS_ALIGN_UP( stack_size, CPU_STACK_ALIGNMENT );
+
   return stack_size;
 }
 

cpukit/include/rtems/score/tls.h

@@ -122,17 +122,17 @@ static inline uintptr_t _TLS_Get_size( void )
 }
 
 /**
- * @brief Returns the value aligned up to the heap alignment.
+ * @brief Returns the value aligned up to the stack alignment.
  *
  * @param val The value to align.
  *
- * @return The value aligned to the heap alignment.
+ * @return The value aligned to the stack alignment.
  */
-static inline uintptr_t _TLS_Heap_align_up( uintptr_t val )
+static inline uintptr_t _TLS_Align_up( uintptr_t val )
 {
-  uintptr_t msk = CPU_HEAP_ALIGNMENT - 1;
+  uintptr_t alignment = CPU_STACK_ALIGNMENT;
 
-  return (val + msk) & ~msk;
+  return RTEMS_ALIGN_UP( val, alignment );
 }
 
 /**
@@ -229,7 +229,7 @@ static inline void *_TLS_TCB_at_area_begin_initialize( void *tls_area )
   void *tls_block = (char *) tls_area
     + _TLS_Get_thread_control_block_area_size( (uintptr_t) _TLS_Alignment );
   TLS_Thread_control_block *tcb = tls_area;
-  uintptr_t aligned_size = _TLS_Heap_align_up( (uintptr_t) _TLS_Size );
+  uintptr_t aligned_size = _TLS_Align_up( (uintptr_t) _TLS_Size );
   TLS_Dynamic_thread_vector *dtv = (TLS_Dynamic_thread_vector *)
     ((char *) tls_block + aligned_size);
 
@@ -253,7 +253,7 @@ static inline void *_TLS_TCB_before_TLS_block_initialize( void *tls_area )
     + _TLS_Get_thread_control_block_area_size( (uintptr_t) _TLS_Alignment );
   TLS_Thread_control_block *tcb = (TLS_Thread_control_block *)
     ((char *) tls_block - sizeof(*tcb));
-  uintptr_t aligned_size = _TLS_Heap_align_up( (uintptr_t) _TLS_Size );
+  uintptr_t aligned_size = _TLS_Align_up( (uintptr_t) _TLS_Size );
   TLS_Dynamic_thread_vector *dtv = (TLS_Dynamic_thread_vector *)
     ((char *) tls_block + aligned_size);
 
@@ -276,7 +276,7 @@ static inline void *_TLS_TCB_after_TLS_block_initialize( void *tls_area )
   uintptr_t size = (uintptr_t) _TLS_Size;
   uintptr_t tls_align = (uintptr_t) _TLS_Alignment;
   uintptr_t tls_mask = tls_align - 1;
-  uintptr_t heap_align = _TLS_Heap_align_up( tls_align );
+  uintptr_t heap_align = _TLS_Align_up( tls_align );
   uintptr_t heap_mask = heap_align - 1;
   TLS_Thread_control_block *tcb = (TLS_Thread_control_block *)
     ((char *) tls_area + ((size + heap_mask) & ~heap_mask));

cpukit/score/src/threadinitialize.c

@@ -107,6 +107,7 @@ static bool _Thread_Try_initialize(
   size_t                   i;
   char                    *stack_begin;
   char                    *stack_end;
+  uintptr_t                stack_align;
   Scheduler_Node          *scheduler_node;
 #if defined(RTEMS_SMP)
   Scheduler_Node          *scheduler_node_for_index;
@@ -128,8 +129,12 @@ static bool _Thread_Try_initialize(
       (char *) the_thread + add_on->source_offset;
   }
 
+  /* Set up the properly aligned stack area begin and end */
   stack_begin = config->stack_area;
   stack_end = stack_begin + config->stack_size;
+  stack_align = CPU_STACK_ALIGNMENT;
+  stack_begin = (char *) RTEMS_ALIGN_UP( (uintptr_t) stack_begin, stack_align );
+  stack_end = (char *) RTEMS_ALIGN_DOWN( (uintptr_t) stack_end, stack_align );
 
   /* Allocate floating-point context in stack area */
 #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )

cpukit/score/src/tlsallocsize.c

@@ -48,7 +48,6 @@ uintptr_t _TLS_Get_allocation_size( void )
 {
   uintptr_t size;
   uintptr_t allocation_size;
-  uintptr_t alignment;
 
   size = _TLS_Get_size();
 
@@ -59,25 +58,34 @@ uintptr_t _TLS_Get_allocation_size( void )
   allocation_size = _TLS_Allocation_size;
 
   if ( allocation_size == 0 ) {
-    allocation_size = _TLS_Heap_align_up( size );
-    alignment = _TLS_Heap_align_up( (uintptr_t) _TLS_Alignment );
+    uintptr_t alignment;
+
+    alignment = _TLS_Align_up( (uintptr_t) _TLS_Alignment );
+
+    allocation_size = size;
+    allocation_size += _TLS_Get_thread_control_block_area_size( alignment );
+#ifndef __i386__
+    allocation_size += sizeof( TLS_Dynamic_thread_vector );
+#endif
+
+    /*
+     * The TLS area is allocated in the thread storage area.  Each allocation
+     * shall meet the stack alignment requirement.
+     */
+    allocation_size = _TLS_Align_up( allocation_size );
 
     /*
      * The stack allocator does not support aligned allocations.  Allocate
      * enough to do the alignment manually.
      */
-    if ( alignment > CPU_HEAP_ALIGNMENT ) {
-      allocation_size += alignment;
+    if ( alignment > CPU_STACK_ALIGNMENT ) {
+      _Assert( alignment % CPU_STACK_ALIGNMENT == 0 );
+      allocation_size += alignment - CPU_STACK_ALIGNMENT;
     }
 
-    allocation_size += _TLS_Get_thread_control_block_area_size( alignment );
-
-#ifndef __i386__
-    allocation_size += sizeof(TLS_Dynamic_thread_vector);
-#endif
-
     if ( _Thread_Maximum_TLS_size != 0 ) {
       if ( allocation_size <= _Thread_Maximum_TLS_size ) {
+        _Assert( _Thread_Maximum_TLS_size % CPU_STACK_ALIGNMENT == 0 );
         allocation_size = _Thread_Maximum_TLS_size;
       } else {
         _Internal_error( INTERNAL_ERROR_TOO_LARGE_TLS_SIZE );