[rtems commit] score: Introduce CPU_CACHE_LINE_BYTES
Sebastian Huber
sebh at rtems.org
Tue Jan 26 08:11:41 UTC 2016
Module: rtems
Branch: master
Commit: a8865f8b415788c4e9bb7f68e38d41aec0e485db
Changeset: http://git.rtems.org/rtems/commit/?id=a8865f8b415788c4e9bb7f68e38d41aec0e485db
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Mon Jan 25 10:20:28 2016 +0100
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.
---
c/src/lib/libcpu/shared/src/cache_manager.c | 8 ++++++++
cpukit/score/cpu/arm/rtems/score/cpu.h | 6 ++++--
cpukit/score/cpu/bfin/rtems/score/cpu.h | 26 +++-----------------------
cpukit/score/cpu/epiphany/rtems/score/cpu.h | 24 +++---------------------
cpukit/score/cpu/i386/rtems/score/cpu.h | 4 ++++
cpukit/score/cpu/lm32/rtems/score/cpu.h | 28 ++++------------------------
cpukit/score/cpu/m32c/rtems/score/cpu.h | 28 ++++------------------------
cpukit/score/cpu/m68k/rtems/score/cpu.h | 6 +++++-
cpukit/score/cpu/mips/rtems/score/cpu.h | 28 +++-------------------------
cpukit/score/cpu/moxie/rtems/score/cpu.h | 26 +++-----------------------
cpukit/score/cpu/nios2/rtems/score/cpu.h | 6 +++++-
cpukit/score/cpu/no_cpu/rtems/score/cpu.h | 21 ++++++++-------------
cpukit/score/cpu/or1k/rtems/score/cpu.h | 24 +++---------------------
cpukit/score/cpu/powerpc/rtems/score/cpu.h | 23 ++---------------------
cpukit/score/cpu/sh/rtems/score/cpu.h | 23 +++--------------------
cpukit/score/cpu/sparc/rtems/score/cpu.h | 15 ++++-----------
cpukit/score/cpu/sparc64/rtems/score/cpu.h | 5 ++++-
cpukit/score/cpu/v850/rtems/score/cpu.h | 26 +++-----------------------
18 files changed, 73 insertions(+), 254 deletions(-)
diff --git a/c/src/lib/libcpu/shared/src/cache_manager.c b/c/src/lib/libcpu/shared/src/cache_manager.c
index 202ea8e..255f621 100644
--- a/c/src/lib/libcpu/shared/src/cache_manager.c
+++ b/c/src/lib/libcpu/shared/src/cache_manager.c
@@ -42,6 +42,14 @@
#include <rtems.h>
#include "cache_.h"
+#if CPU_DATA_CACHE_ALIGNMENT > CPU_CACHE_LINE_BYTES
+#error "CPU_DATA_CACHE_ALIGNMENT is greater than CPU_CACHE_LINE_BYTES"
+#endif
+
+#if CPU_INSTRUCTION_CACHE_ALIGNMENT > CPU_CACHE_LINE_BYTES
+#error "CPU_INSTRUCTION_CACHE_ALIGNMENT is greater than CPU_CACHE_LINE_BYTES"
+#endif
+
#if defined(RTEMS_SMP)
#include <rtems/score/smpimpl.h>
diff --git a/cpukit/score/cpu/arm/rtems/score/cpu.h b/cpukit/score/cpu/arm/rtems/score/cpu.h
index 089d4293..89b7609 100644
--- a/cpukit/score/cpu/arm/rtems/score/cpu.h
+++ b/cpukit/score/cpu/arm/rtems/score/cpu.h
@@ -144,8 +144,10 @@
#define CPU_STACK_GROWS_UP FALSE
-/* XXX Why 32? */
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (32)))
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* The interrupt mask disables only normal interrupts (IRQ).
diff --git a/cpukit/score/cpu/bfin/rtems/score/cpu.h b/cpukit/score/cpu/bfin/rtems/score/cpu.h
index 8257383..f4da07d 100644
--- a/cpukit/score/cpu/bfin/rtems/score/cpu.h
+++ b/cpukit/score/cpu/bfin/rtems/score/cpu.h
@@ -295,29 +295,9 @@ extern "C" {
*/
#define CPU_STACK_GROWS_UP FALSE
-/**
- * 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
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
#define CPU_STRUCTURE_ALIGNMENT
/**
diff --git a/cpukit/score/cpu/epiphany/rtems/score/cpu.h b/cpukit/score/cpu/epiphany/rtems/score/cpu.h
index 967b802..aa786cd 100644
--- a/cpukit/score/cpu/epiphany/rtems/score/cpu.h
+++ b/cpukit/score/cpu/epiphany/rtems/score/cpu.h
@@ -260,28 +260,10 @@ extern "C" {
#define CPU_STACK_GROWS_UP FALSE
-/*
- * 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.
- *
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 64
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (64)))
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/i386/rtems/score/cpu.h b/cpukit/score/cpu/i386/rtems/score/cpu.h
index 8a49597..5a8e5d6 100644
--- a/cpukit/score/cpu/i386/rtems/score/cpu.h
+++ b/cpukit/score/cpu/i386/rtems/score/cpu.h
@@ -100,6 +100,10 @@ extern "C" {
#endif /* __SSE__ */
#define CPU_STACK_GROWS_UP FALSE
+
+/* FIXME: The Pentium 4 used 128 bytes, it this processor still relevant? */
+#define CPU_CACHE_LINE_BYTES 64
+
#define CPU_STRUCTURE_ALIGNMENT
/*
diff --git a/cpukit/score/cpu/lm32/rtems/score/cpu.h b/cpukit/score/cpu/lm32/rtems/score/cpu.h
index 1a61475..dd0ec47 100644
--- a/cpukit/score/cpu/lm32/rtems/score/cpu.h
+++ b/cpukit/score/cpu/lm32/rtems/score/cpu.h
@@ -289,30 +289,10 @@ extern "C" {
*/
#define CPU_STACK_GROWS_UP FALSE
-/**
- * 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:
- *
- * L2 cache lines are 32 bytes in Milkymist SoC
- */
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (32)))
+/* L2 cache lines are 32 bytes in Milkymist SoC */
+#define CPU_CACHE_LINE_BYTES 32
+
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/**
* @defgroup CPUEndian Processor Dependent Endianness Support
diff --git a/cpukit/score/cpu/m32c/rtems/score/cpu.h b/cpukit/score/cpu/m32c/rtems/score/cpu.h
index 6819c82..59e9b4e 100644
--- a/cpukit/score/cpu/m32c/rtems/score/cpu.h
+++ b/cpukit/score/cpu/m32c/rtems/score/cpu.h
@@ -311,30 +311,10 @@ extern "C" {
*/
#define CPU_STACK_GROWS_UP TRUE
-/**
- * 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 __attribute__ ((aligned (2)))
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 2
+
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/**
* @defgroup CPUEndian Processor Dependent Endianness Support
diff --git a/cpukit/score/cpu/m68k/rtems/score/cpu.h b/cpukit/score/cpu/m68k/rtems/score/cpu.h
index 47a2d8e..8e0efa1 100644
--- a/cpukit/score/cpu/m68k/rtems/score/cpu.h
+++ b/cpukit/score/cpu/m68k/rtems/score/cpu.h
@@ -99,7 +99,11 @@ extern "C" {
#define CPU_PROVIDES_IDLE_THREAD_BODY TRUE
#define CPU_STACK_GROWS_UP FALSE
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (4)))
+
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 16
+
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/mips/rtems/score/cpu.h b/cpukit/score/cpu/mips/rtems/score/cpu.h
index bb897e1..01bd29a 100644
--- a/cpukit/score/cpu/mips/rtems/score/cpu.h
+++ b/cpukit/score/cpu/mips/rtems/score/cpu.h
@@ -280,32 +280,10 @@ extern "C" {
/* our stack grows down */
#define CPU_STACK_GROWS_UP FALSE
-/*
- * 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.
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 16
-/* our cache line size is 16 bytes */
-#if __GNUC__
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (16)))
-#else
-#define CPU_STRUCTURE_ALIGNMENT
-#endif
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/moxie/rtems/score/cpu.h b/cpukit/score/cpu/moxie/rtems/score/cpu.h
index 8348d48..4e4bbad 100644
--- a/cpukit/score/cpu/moxie/rtems/score/cpu.h
+++ b/cpukit/score/cpu/moxie/rtems/score/cpu.h
@@ -260,29 +260,9 @@ extern "C" {
*/
#define CPU_STACK_GROWS_UP FALSE
-/*
- * 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.
- *
- * MOXIE Specific Information:
- *
- * XXX
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
#define CPU_STRUCTURE_ALIGNMENT
/*
diff --git a/cpukit/score/cpu/nios2/rtems/score/cpu.h b/cpukit/score/cpu/nios2/rtems/score/cpu.h
index 4bd1fe7..1008865 100644
--- a/cpukit/score/cpu/nios2/rtems/score/cpu.h
+++ b/cpukit/score/cpu/nios2/rtems/score/cpu.h
@@ -64,7 +64,11 @@ extern "C" {
#define CPU_STACK_GROWS_UP FALSE
-#define CPU_STRUCTURE_ALIGNMENT __attribute__((section(".sdata"), aligned(32)))
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
+#define CPU_STRUCTURE_ALIGNMENT \
+ RTEMS_SECTION( ".sdata" ) RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
#define CPU_BIG_ENDIAN FALSE
diff --git a/cpukit/score/cpu/no_cpu/rtems/score/cpu.h b/cpukit/score/cpu/no_cpu/rtems/score/cpu.h
index ab81e64..67a725c 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
diff --git a/cpukit/score/cpu/or1k/rtems/score/cpu.h b/cpukit/score/cpu/or1k/rtems/score/cpu.h
index c9b833c..2405844 100644
--- a/cpukit/score/cpu/or1k/rtems/score/cpu.h
+++ b/cpukit/score/cpu/or1k/rtems/score/cpu.h
@@ -252,28 +252,10 @@ extern "C" {
#define CPU_STACK_GROWS_UP FALSE
-/*
- * 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.
- *
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (32)))
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/powerpc/rtems/score/cpu.h b/cpukit/score/cpu/powerpc/rtems/score/cpu.h
index 5e822e4..f988f8a 100644
--- a/cpukit/score/cpu/powerpc/rtems/score/cpu.h
+++ b/cpukit/score/cpu/powerpc/rtems/score/cpu.h
@@ -101,28 +101,9 @@ extern "C" {
#define CPU_STACK_GROWS_UP FALSE
-/*
- * 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.
- */
+#define CPU_CACHE_LINE_BYTES PPC_STRUCTURE_ALIGNMENT
-#define CPU_STRUCTURE_ALIGNMENT \
- __attribute__ ((aligned (PPC_STRUCTURE_ALIGNMENT)))
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/sh/rtems/score/cpu.h b/cpukit/score/cpu/sh/rtems/score/cpu.h
index bf12220..43d1915 100644
--- a/cpukit/score/cpu/sh/rtems/score/cpu.h
+++ b/cpukit/score/cpu/sh/rtems/score/cpu.h
@@ -229,27 +229,10 @@ extern "C" {
#define CPU_STACK_GROWS_UP FALSE
-/*
- * 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.
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 16
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned(16)))
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/sparc/rtems/score/cpu.h b/cpukit/score/cpu/sparc/rtems/score/cpu.h
index 9b4db13..4170cb9 100644
--- a/cpukit/score/cpu/sparc/rtems/score/cpu.h
+++ b/cpukit/score/cpu/sparc/rtems/score/cpu.h
@@ -210,17 +210,10 @@ extern "C" {
*/
#define CPU_STACK_GROWS_UP FALSE
-/**
- * The following is the variable attribute used to force alignment
- * of critical data 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 SPARC does not appear to have particularly strict alignment
- * requirements. This value was chosen to take advantages of caches.
- */
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (32)))
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
/**
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/sparc64/rtems/score/cpu.h b/cpukit/score/cpu/sparc64/rtems/score/cpu.h
index 4838cac..80c3466 100644
--- a/cpukit/score/cpu/sparc64/rtems/score/cpu.h
+++ b/cpukit/score/cpu/sparc64/rtems/score/cpu.h
@@ -170,6 +170,9 @@ extern "C" {
#define CPU_STACK_GROWS_UP FALSE
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
/*
* The following is the variable attribute used to force alignment
* of critical data structures. On some processors it may make
@@ -184,7 +187,7 @@ extern "C" {
* and is 16 if quad-word fp instructions are available (e.g. LDQF).
*/
-#define CPU_STRUCTURE_ALIGNMENT __attribute__ ((aligned (16)))
+#define CPU_STRUCTURE_ALIGNMENT RTEMS_ALIGNED( 16 )
/*
* Define what is required to specify how the network to host conversion
diff --git a/cpukit/score/cpu/v850/rtems/score/cpu.h b/cpukit/score/cpu/v850/rtems/score/cpu.h
index b2b9fc1..e910ae1 100644
--- a/cpukit/score/cpu/v850/rtems/score/cpu.h
+++ b/cpukit/score/cpu/v850/rtems/score/cpu.h
@@ -289,29 +289,9 @@ extern "C" {
*/
#define CPU_STACK_GROWS_UP FALSE
-/**
- * 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:
- *
- * Until proven otherwise, use the compiler default.
- */
+/* FIXME: Is this the right value? */
+#define CPU_CACHE_LINE_BYTES 32
+
#define CPU_STRUCTURE_ALIGNMENT
/**
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