openrisc: Reserve memblock for initrd

Recently OpenRISC added support for external initrd images, but I found
some instability when using larger buildroot initrd images. It turned
out that I forgot to reserve the memblock space for the initrd image.

This patch fixes the instability issue by reserving memblock space.

Fixes: ff6c923d ("openrisc: Add support for external initrd images")
Signed-off-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>

arch/openrisc/kernel/setup.c

@@ -80,6 +80,16 @@ static void __init setup_memory(void)
 	 */
 	memblock_reserve(__pa(_stext), _end - _stext);
 
+#ifdef CONFIG_BLK_DEV_INITRD
+	/* Then reserve the initrd, if any */
+	if (initrd_start && (initrd_end > initrd_start)) {
+		unsigned long aligned_start = ALIGN_DOWN(initrd_start, PAGE_SIZE);
+		unsigned long aligned_end = ALIGN(initrd_end, PAGE_SIZE);
+
+		memblock_reserve(__pa(aligned_start), aligned_end - aligned_start);
+	}
+#endif /* CONFIG_BLK_DEV_INITRD */
+
 	early_init_fdt_reserve_self();
 	early_init_fdt_scan_reserved_mem();