score: Introduce CPU_CACHE_LINE_BYTES

Add CPU_CACHE_LINE_BYTES for the maximum cache line size in bytes.  The
actual processor may use no cache or a smaller cache line size.

1 files changed, 8 insertions, 13 deletions

diff --git a/cpukit/score/cpu/no_cpu/rtems/score/cpu.h b/cpukit/score/cpu/no_cpu/rtems/score/cpu.h
index ab81e649ef..67a725c09d 100644
--- a/cpukit/score/cpu/no_cpu/rtems/score/cpu.h
+++ b/cpukit/score/cpu/no_cpu/rtems/score/cpu.h
@@ -311,29 +311,24 @@ extern "C" {
 #define CPU_STACK_GROWS_UP               TRUE
 
 /**
+ * The maximum cache line size in bytes.
+ *
+ * The actual processor may use no cache or a smaller cache line size.
+ */
+#define CPU_CACHE_LINE_BYTES 32
+
+/**
  * The following is the variable attribute used to force alignment
  * of critical RTEMS structures.  On some processors it may make
  * sense to have these aligned on tighter boundaries than
  * the minimum requirements of the compiler in order to have as
  * much of the critical data area as possible in a cache line.
  *
- * The placement of this macro in the declaration of the variables
- * is based on the syntactically requirements of the GNU C
- * "__attribute__" extension.  For example with GNU C, use
- * the following to force a structures to a 32 byte boundary.
- *
- *     __attribute__ ((aligned (32)))
- *
- * NOTE: Currently only the Priority Bit Map table uses this feature.
- *       To benefit from using this, the data must be heavily
- *       used so it will stay in the cache and used frequently enough
- *       in the executive to justify turning this on.
- *
  * Port Specific Information:
  *
  * XXX document implementation including references if appropriate
  */
-#define CPU_STRUCTURE_ALIGNMENT
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
 
 /**
  * @defgroup CPUEndian Processor Dependent Endianness Support