x86_64: acpi: bring up other APs in long mode

arch/x86_64/e820.c

@@ -44,10 +44,13 @@ void e820_scan(multiboot_memory_map_t *mmap, size_t len)
 			memblock_reserve(entry->addr, entry->len);
 			mem_reserved += entry->len;
 		}
-		
+
 		mem_total += entry->len;
 	}
 
+	/* reserve a page at 0x8000 for use by the ACPI AP trampoline code */
+	memblock_reserve(0x8000, 0x1000);
+
 	char str_mem_total[64], str_mem_reserved[64];
 	data_size_to_string(mem_total, str_mem_total, sizeof str_mem_total);
 	data_size_to_string(mem_reserved, str_mem_reserved, sizeof str_mem_reserved);