From cf28ccfb06f80d3e219ebcae3e7586fbe8c41e34 Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@bug.st>
Date: Mon, 13 Aug 2012 14:44:30 +0200
Subject: [PATCH] Fixed linker script to allow growing stack+heap.

---
 .../arduino_due_x/linker_scripts/gcc/flash.ld | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/hardware/arduino/sam/variants/arduino_due_x/linker_scripts/gcc/flash.ld b/hardware/arduino/sam/variants/arduino_due_x/linker_scripts/gcc/flash.ld
index 7afb12b33..53f2b5f1f 100644
--- a/hardware/arduino/sam/variants/arduino_due_x/linker_scripts/gcc/flash.ld
+++ b/hardware/arduino/sam/variants/arduino_due_x/linker_scripts/gcc/flash.ld
@@ -40,8 +40,6 @@ MEMORY
 	ram (rwx)   : ORIGIN = 0x20070000, LENGTH = 0x00018000 /* sram, 96K */
 }
 
-RAM_END = 0x20088000 ; /* There is a way to define this as ram.ORIGIN + ram.LENGTH ? */
-
 /* Section Definitions */
 SECTIONS
 {
@@ -116,7 +114,7 @@ SECTIONS
     } > ram
 
     /* .bss section which is used for uninitialized data */
-    .bss (NOLOAD) :
+    .bss ALIGN(4) (NOLOAD) :
     {
         . = ALIGN(4);
         _sbss = . ;
@@ -131,10 +129,18 @@ SECTIONS
     . = ALIGN(4);
     _end = . ;
 
-    /* put stack section at the bottom of ram space */
-    .stack RAM_END (NOLOAD):
+    /* .stack_dummy section doesn't contains any symbols. It is only
+       used for linker to calculate size of stack sections, and assign
+       values to stack symbols later */
+    .stack_dummy :
     {
-        _sstack = .;
-        _estack = .;
+        *(.stack*)
     } > ram
+
+    /* Set stack top to end of ram, and stack limit move down by
+     * size of stack_dummy section */
+    __StackTop = ORIGIN(ram) + LENGTH(ram);
+    __StackLimit = __StackTop - SIZEOF(.stack_dummy);
+    PROVIDE(_sstack = __StackLimit);
+    PROVIDE(_estack = __StackTop);
 }