efi_get_random_bytes
efi_status_t efi_get_random_bytes(unsigned long size, u8 *out);
efi_status = efi_get_random_bytes(sizeof(fdt_val64),
status = efi_get_random_bytes(sizeof(phys_seed),
efi_get_random_bytes(size, seed);
status = efi_get_random_bytes(sizeof(seed), (u8 *)&seed);