UMM: Implement getter for address environment heap start vaddr

Using the Kconfig macro does not work for RISC-V target, as there the
user heap follows .data/.bss and does not obey any Kconfig provided
boundary.

Added stubs for ARM and Z80 also.

arch/arm/src/armv7-a/arm_addrenv.c

@@ -447,6 +447,33 @@ int up_addrenv_vdata(group_addrenv_t *addrenv, uintptr_t textsize,
   return OK;
 }
 
+/****************************************************************************
+ * Name: up_addrenv_vheap
+ *
+ * Description:
+ *   Return the heap virtual address associated with the newly created
+ *   address environment.  This function is used by the binary loaders in
+ *   order get an address that can be used to initialize the new task.
+ *
+ * Input Parameters:
+ *   addrenv - The representation of the task address environment previously
+ *      returned by up_addrenv_create.
+ *   vheap - The location to return the virtual address.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_BUILD_KERNEL
+int up_addrenv_vheap(const group_addrenv_t *addrenv, void **vheap)
+{
+  DEBUGASSERT(addrenv && vheap);
+  *vheap = (void *)CONFIG_ARCH_HEAP_VBASE;
+  return OK;
+}
+#endif
+
 /****************************************************************************
  * Name: up_addrenv_heapsize
  *

arch/risc-v/src/common/riscv_addrenv.c

@@ -590,6 +590,33 @@ int up_addrenv_vdata(group_addrenv_t *addrenv, uintptr_t textsize,
   return OK;
 }
 
+/****************************************************************************
+ * Name: up_addrenv_vheap
+ *
+ * Description:
+ *   Return the heap virtual address associated with the newly created
+ *   address environment.  This function is used by the binary loaders in
+ *   order get an address that can be used to initialize the new task.
+ *
+ * Input Parameters:
+ *   addrenv - The representation of the task address environment previously
+ *      returned by up_addrenv_create.
+ *   vheap - The location to return the virtual address.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_BUILD_KERNEL
+int up_addrenv_vheap(const group_addrenv_t *addrenv, void **vheap)
+{
+  DEBUGASSERT(addrenv && vheap);
+  *vheap = (void *)addrenv->heapvbase;
+  return OK;
+}
+#endif
+
 /****************************************************************************
  * Name: up_addrenv_heapsize
  *

arch/z80/src/z180/z180_mmu.c

@@ -375,6 +375,33 @@ int up_addrenv_vdata(FAR group_addrenv_t *addrenv, uintptr_t textsize,
   return CONFIG_Z180_COMMON1AREA_VIRTBASE + textsize;
 }
 
+/****************************************************************************
+ * Name: up_addrenv_vheap
+ *
+ * Description:
+ *   Return the heap virtual address associated with the newly created
+ *   address environment.  This function is used by the binary loaders in
+ *   order get an address that can be used to initialize the new task.
+ *
+ * Input Parameters:
+ *   addrenv - The representation of the task address environment previously
+ *      returned by up_addrenv_create.
+ *   vheap - The location to return the virtual address.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_BUILD_KERNEL
+int up_addrenv_vheap(FAR const group_addrenv_t *addrenv, FAR void **vheap)
+{
+  /* Not implemented */
+
+  return -ENOSYS;
+}
+#endif
+
 /****************************************************************************
  * Name: up_addrenv_heapsize
  *