arch/addrenv: Add utility function to wipe one page

up_addrenv_page_wipe can be used to wipe a single page of memory.

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

@@ -147,6 +147,26 @@ bool up_addrenv_user_vaddr(uintptr_t vaddr)
   return riscv_uservaddr(vaddr);
 }
 
+/****************************************************************************
+ * Name: up_addrenv_page_wipe
+ *
+ * Description:
+ *   Wipe a page of physical memory, first mapping it into kernel virtual
+ *   memory.
+ *
+ * Input Parameters:
+ *   page - The page physical address.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+void up_addrenv_page_wipe(uintptr_t page)
+{
+  riscv_pgwipe(page);
+}
+
 #ifdef CONFIG_MM_KMAP
 
 /****************************************************************************

include/nuttx/arch.h

@@ -1318,14 +1318,33 @@ uintptr_t up_addrenv_page_vaddr(uintptr_t page);
  *   vaddr - The virtual address.
  *
  * Returned Value:
- *   True if it is; false if it's not
+ *   True if it is; false if it's not.
  *
  ****************************************************************************/
 
 #ifdef CONFIG_ARCH_ADDRENV
 bool up_addrenv_user_vaddr(uintptr_t vaddr);
 #endif
 
+/****************************************************************************
+ * Name: up_addrenv_page_wipe
+ *
+ * Description:
+ *   Wipe a page of physical memory, first mapping it into kernel virtual
+ *   memory.
+ *
+ * Input Parameters:
+ *   page - The page physical address.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_ARCH_ADDRENV
+void up_addrenv_page_wipe(uintptr_t page);
+#endif
+
 /****************************************************************************
  * Name: up_addrenv_kmap_init
  *