Add a test for heap and stack layout

Test the following components of the heap and stacks:
-Heap and interrupt stack are at the expected locations
-Entire heap can be used
-Heap limit is properly enforced and returns NULL when out of
  of memory

rtos/rtx/TARGET_CORTEX_M/TESTS/memory/heap_and_stack/main.cpp

@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2016-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "greentea-client/test_env.h"
+#include "cmsis.h"
+#include "mbed.h"
+#include "rtos.h"
+#include "mbed_assert.h"
+
+// Amount to malloc for each iteration
+#define MALLOC_TEST_SIZE            256
+// Malloc fill pattern
+#define MALLOC_FILL                 0x55
+
+extern uint32_t mbed_heap_start;
+extern uint32_t mbed_heap_size;
+extern uint32_t mbed_stack_isr_start;
+extern uint32_t mbed_stack_isr_size;
+
+static uint32_t max_allocation_size = 0;
+
+static bool inrange(uint32_t addr, uint32_t start, uint32_t size);
+static bool rangeinrange(uint32_t addr, uint32_t size, uint32_t start, uint32_t len);
+static bool valid_fill(uint8_t * data, uint32_t size, uint8_t fill);
+static bool allocate_and_fill_heap(void);
+static bool check_and_free_heap(void);
+
+int main (void) {
+    GREENTEA_SETUP(30, "default_auto");
+
+    char c;
+    char * initial_stack = &c;
+    char *initial_heap;
+
+    // Sanity check malloc
+    initial_heap = (char*)malloc(1);
+    if (initial_heap == NULL) {
+        printf("Unable to malloc a single byte\n");
+        GREENTEA_TESTSUITE_RESULT(false);
+    }
+
+    if (!inrange((uint32_t)initial_heap, mbed_heap_start, mbed_heap_size)) {
+        printf("Heap in wrong location\n");
+        GREENTEA_TESTSUITE_RESULT(false);
+    }
+    // MSP stack should be very near end (test using within 128 bytes)
+    uint32_t msp = __get_MSP();
+    if (!inrange(msp, mbed_stack_isr_start + mbed_stack_isr_size - 128, 128)) {
+        printf("Interrupt stack in wrong location\n");
+        GREENTEA_TESTSUITE_RESULT(false);
+    }
+
+    // Fully allocate the heap and stack
+    bool ret = true;
+    ret = ret && allocate_and_fill_heap();
+    ret = ret && check_and_free_heap();
+
+    // Force a task switch so a stack check is performed
+    Thread::wait(10);
+
+    printf("Total size dynamically allocated: %lu\n", max_allocation_size);
+
+    GREENTEA_TESTSUITE_RESULT(ret);
+}
+
+/*
+ * Return true if addr is in range [start:start+size)
+ */
+static bool inrange(uint32_t addr, uint32_t start, uint32_t size)
+{
+    return (addr >= start) && (addr < start + size) ? true : false;
+}
+
+/*
+ * Return true if [addr:addr+size] is inside [start:start+len]
+ */
+static bool rangeinrange(uint32_t addr, uint32_t size, uint32_t start, uint32_t len)
+{
+    if (addr + size > start + len) {
+        return false;
+    }
+    if (addr < start) {
+        return false;
+    }
+    return true;
+}
+
+/*
+ * Return true of the region is filled only the the specified fill value
+ */
+static bool valid_fill(uint8_t * data, uint32_t size, uint8_t fill)
+{
+    for (uint32_t i = 0; i < size; i++) {
+        if (data[i] != fill) {
+            return false;
+        }
+    }
+    return true;
+}
+
+struct linked_list {
+    linked_list * next;
+    uint8_t data[MALLOC_TEST_SIZE];
+};
+
+static linked_list *head = NULL;
+static bool allocate_and_fill_heap()
+{
+
+    linked_list *current;
+
+    current = (linked_list*)malloc(sizeof(linked_list));
+    if (0 == current) {
+        return false;
+    }
+    current->next = NULL;
+    memset((void*)current->data, MALLOC_FILL, sizeof(current->data));
+
+    // Allocate until malloc returns NULL
+    bool pass = true;
+    head = current;
+    while (true) {
+
+        // Allocate
+        linked_list *temp = (linked_list*)malloc(sizeof(linked_list));
+        if (NULL == temp) {
+            break;
+        }
+        if (!rangeinrange((uint32_t)temp, sizeof(linked_list), mbed_heap_start, mbed_heap_size)) {
+            printf("Memory allocation out of range\n");
+            pass = false;
+            break;
+        }
+
+        // Init
+        temp->next = NULL;
+        memset((void*)temp->data, MALLOC_FILL, sizeof(current->data));
+
+        // Add to list
+        current->next = temp;
+        current = temp;
+    }
+    return pass;
+}
+
+static bool check_and_free_heap()
+{
+    uint32_t total_size = 0;
+    linked_list * current = head;
+    bool pass = true;
+    while (current != NULL) {
+        total_size += sizeof(linked_list);
+        if (!valid_fill(current->data, sizeof(current->data), MALLOC_FILL)) {
+            pass = false;
+        }
+        linked_list * next = current->next;
+        free(current);
+        current = next;
+    }
+
+    max_allocation_size = total_size;
+    return pass;
+}