From 9216504ce3f825f59494facac637ded42f1cbe04 Mon Sep 17 00:00:00 2001
From: inmarket <inmarket@ugfx.org>
Date: Mon, 9 Jan 2017 10:24:49 +1000
Subject: [PATCH] Ensure stack size produces an aligned stack on platforms
 where it matters

---
 src/gos/gos.h           | 6 +++++-
 src/gos/gos_ecos.h      | 2 +-
 src/gos/gos_freertos.h  | 2 +-
 src/gos/gos_rawrtos.h   | 2 +-
 src/gos/gos_x_threads.h | 2 +-
 5 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/gos/gos.h b/src/gos/gos.h
index 09b278bc..ddca0d94 100644
--- a/src/gos/gos.h
+++ b/src/gos/gos.h
@@ -65,7 +65,11 @@
 	 * @brief	Declare a thread stack
 	 *
 	 * @param[in] name 		The name of the stack
-	 * @param[in] sz 		The size of the stack
+	 * @param[in] sz 		The size of the stack in bytes
+	 *
+	 * @note	The size provided is just a suggestion to the required stack size.
+	 * 			Many platforms will round the size to ensure correct stack alignment.
+	 *			Other platforms may entirely ignore the suggested size.
 	 */
 	#define DECLARE_THREAD_STACK(name, sz)			uint8_t name[sz];
 
diff --git a/src/gos/gos_ecos.h b/src/gos/gos_ecos.h
index cd5678df..6aa55a3a 100644
--- a/src/gos/gos_ecos.h
+++ b/src/gos/gos_ecos.h
@@ -44,7 +44,7 @@ typedef cyg_handle_t		gfxThreadHandle;
 #define NORMAL_PRIORITY				(CYGNUM_KERNEL_SCHED_PRIORITIES/2)
 #define HIGH_PRIORITY				0
 
-#define DECLARE_THREAD_STACK(name, sz)			struct { cyg_thread t; unsigned char stk[sz]; } name[1]
+#define DECLARE_THREAD_STACK(name, sz)			struct { cyg_thread t; unsigned char stk[(sz) & ~3]; } name[1]
 #define DECLARE_THREAD_FUNCTION(fnName, param)	threadreturn_t fnName(cyg_addrword_t param)
 #define THREAD_RETURN(retval)
 
diff --git a/src/gos/gos_freertos.h b/src/gos/gos_freertos.h
index 9b3d1023..92b48024 100644
--- a/src/gos/gos_freertos.h
+++ b/src/gos/gos_freertos.h
@@ -60,7 +60,7 @@ typedef portBASE_TYPE		threadpriority_t;
 #define HIGH_PRIORITY		configMAX_PRIORITIES-1
 
 /* FreeRTOS will allocate the stack when creating the thread, so pass the size instead of a working area */
-#define DECLARE_THREAD_STACK(name, sz)			size_t *name = (size_t *)sz
+#define DECLARE_THREAD_STACK(name, sz)			size_t *name = (size_t *)(sz)
 #define DECLARE_THREAD_FUNCTION(fnName, param)	threadreturn_t fnName(void *param)
 #define THREAD_RETURN(retval)
 
diff --git a/src/gos/gos_rawrtos.h b/src/gos/gos_rawrtos.h
index f352d681..e7778d15 100644
--- a/src/gos/gos_rawrtos.h
+++ b/src/gos/gos_rawrtos.h
@@ -26,7 +26,7 @@ typedef RAW_MUTEX			gfxMutex;
 typedef RAW_TASK_OBJ*		gfxThreadHandle;
 
 #define DECLARE_THREAD_FUNCTION(fnName, param)	threadreturn_t fnName(void *param)
-#define DECLARE_THREAD_STACK(name, sz)			PORT_STACK name[sz];
+#define DECLARE_THREAD_STACK(name, sz)			PORT_STACK name[(sz) & ~3];
 #define THREAD_RETURN(retval)					return retval
 
 #define gfxHalt(msg)					for(;;)
diff --git a/src/gos/gos_x_threads.h b/src/gos/gos_x_threads.h
index 585585c5..05a08cc2 100644
--- a/src/gos/gos_x_threads.h
+++ b/src/gos/gos_x_threads.h
@@ -31,7 +31,7 @@ typedef int				threadreturn_t;
 typedef int				threadpriority_t;
 
 #define DECLARE_THREAD_FUNCTION(fnName, param)	threadreturn_t fnName(void *param)
-#define DECLARE_THREAD_STACK(name, sz)			uint8_t name[sz];
+#define DECLARE_THREAD_STACK(name, sz)			uint8_t name[(sz) & ~3];
 #define THREAD_RETURN(retval)					return retval
 
 #define TIME_IMMEDIATE				0