[PATCH v2] score/aarch64: Align context validation frame

[Kinsey Moore]

Ensure the stack remains aligned by keeping the context frame at a
multiple of 16 bytes. This avoids stack alignment exceptions which occur
when the stack pointer is not 16 byte aligned.
---
 .../cpu/aarch64/aarch64-context-validate.S    | 25 +++++++++++--------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/cpukit/score/cpu/aarch64/aarch64-context-validate.S b/cpukit/score/cpu/aarch64/aarch64-context-validate.S
index 57f634934b..07c5ba5a62 100644
--- a/cpukit/score/cpu/aarch64/aarch64-context-validate.S
+++ b/cpukit/score/cpu/aarch64/aarch64-context-validate.S
@@ -54,18 +54,23 @@
 #define FRAME_OFFSET_LR  0x40
 
 #ifdef AARCH64_MULTILIB_VFP
-  #define FRAME_OFFSET_V8  0x48
-  #define FRAME_OFFSET_V9  0x58
-  #define FRAME_OFFSET_V10 0x68
-  #define FRAME_OFFSET_V11 0x78
-  #define FRAME_OFFSET_V12 0x88
-  #define FRAME_OFFSET_V13 0x98
-  #define FRAME_OFFSET_V14 0xA8
-  #define FRAME_OFFSET_V15 0xB8
-
+  /* These must be 16 byte aligned to avoid misaligned accesses */
+  #define FRAME_OFFSET_V8  0x50
+  #define FRAME_OFFSET_V9  0x60
+  #define FRAME_OFFSET_V10 0x70
+  #define FRAME_OFFSET_V11 0x80
+  #define FRAME_OFFSET_V12 0x90
+  #define FRAME_OFFSET_V13 0xA0
+  #define FRAME_OFFSET_V14 0xB0
+  #define FRAME_OFFSET_V15 0xC0
+
+  /*
+   * The frame size must be 16 byte aligned to avoid stack pointer alignment
+   * exceptions.
+   */
   #define FRAME_SIZE (FRAME_OFFSET_V15 + 0x10)
 #else
-  #define FRAME_SIZE (FRAME_OFFSET_LR + 0x08)
+  #define FRAME_SIZE (FRAME_OFFSET_LR + 0x10)
 #endif
 
 	.section	.text
-- 
2.20.1