[rtems commit] arm: Align ARM exception frame to 8 bytes

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    a6c5a7e0b68ea9b9eed98997b85fe49434eeb1c8
Changeset: http://git.rtems.org/rtems/commit/?id=a6c5a7e0b68ea9b9eed98997b85fe49434eeb1c8

Author:    Daniel Krueger <daniel.krueger at systec-electronic.com>
Date:      Tue Mar 17 14:02:59 2015 +0000

arm: Align ARM exception frame to 8 bytes

The stack pointer must be aligned on 8 byte boundary on ARM, so the size of
the exception frame must be a multiple of 8 bytes. Otherwise we might/will
get an alignment fault, when executing code in the data abort handler for
example.

Close #2318.

Signed-off-by: Daniel Krueger <daniel.krueger at systec-electronic.com>

---

 cpukit/score/cpu/arm/cpu.c             | 5 +++++
 cpukit/score/cpu/arm/rtems/score/cpu.h | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/cpukit/score/cpu/arm/cpu.c b/cpukit/score/cpu/arm/cpu.c
index 9942c4a..944ca63 100644
--- a/cpukit/score/cpu/arm/cpu.c
+++ b/cpukit/score/cpu/arm/cpu.c
@@ -64,6 +64,11 @@ RTEMS_STATIC_ASSERT(
 );
 
 RTEMS_STATIC_ASSERT(
+  sizeof( CPU_Exception_frame ) % CPU_STACK_ALIGNMENT == 0,
+  CPU_Exception_frame_alignment
+);
+
+RTEMS_STATIC_ASSERT(
   offsetof( CPU_Exception_frame, register_sp )
     == ARM_EXCEPTION_FRAME_REGISTER_SP_OFFSET,
   ARM_EXCEPTION_FRAME_REGISTER_SP_OFFSET
diff --git a/cpukit/score/cpu/arm/rtems/score/cpu.h b/cpukit/score/cpu/arm/rtems/score/cpu.h
index ca8a09f..6aced79 100644
--- a/cpukit/score/cpu/arm/rtems/score/cpu.h
+++ b/cpukit/score/cpu/arm/rtems/score/cpu.h
@@ -222,7 +222,7 @@
   #endif
 #endif
 
-#define ARM_EXCEPTION_FRAME_SIZE 76
+#define ARM_EXCEPTION_FRAME_SIZE 80
 
 #define ARM_EXCEPTION_FRAME_REGISTER_SP_OFFSET 52
 
@@ -687,6 +687,7 @@ typedef struct {
   uint32_t vector;
 #endif
   const ARM_VFP_context *vfp_context;
+  uint32_t reserved_for_stack_alignment;
 } CPU_Exception_frame;
 
 typedef CPU_Exception_frame CPU_Interrupt_frame;