int __init efi_config_parse_tables()

in efi/efi.c [554:665]

• 89 lines of code
• 20 McCabe index (conditional complexity)

int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
				   int count,
				   const efi_config_table_type_t *arch_tables)
{
	const efi_config_table_64_t *tbl64 = (void *)config_tables;
	const efi_config_table_32_t *tbl32 = (void *)config_tables;
	const efi_guid_t *guid;
	unsigned long table;
	int i;

	pr_info("");
	for (i = 0; i < count; i++) {
		if (!IS_ENABLED(CONFIG_X86)) {
			guid = &config_tables[i].guid;
			table = (unsigned long)config_tables[i].table;
		} else if (efi_enabled(EFI_64BIT)) {
			guid = &tbl64[i].guid;
			table = tbl64[i].table;

			if (IS_ENABLED(CONFIG_X86_32) &&
			    tbl64[i].table > U32_MAX) {
				pr_cont("\n");
				pr_err("Table located above 4GB, disabling EFI.\n");
				return -EINVAL;
			}
		} else {
			guid = &tbl32[i].guid;
			table = tbl32[i].table;
		}

		if (!match_config_table(guid, table, common_tables) && arch_tables)
			match_config_table(guid, table, arch_tables);
	}
	pr_cont("\n");
	set_bit(EFI_CONFIG_TABLES, &efi.flags);

	if (efi_rng_seed != EFI_INVALID_TABLE_ADDR) {
		struct linux_efi_random_seed *seed;
		u32 size = 0;

		seed = early_memremap(efi_rng_seed, sizeof(*seed));
		if (seed != NULL) {
			size = READ_ONCE(seed->size);
			early_memunmap(seed, sizeof(*seed));
		} else {
			pr_err("Could not map UEFI random seed!\n");
		}
		if (size > 0) {
			seed = early_memremap(efi_rng_seed,
					      sizeof(*seed) + size);
			if (seed != NULL) {
				pr_notice("seeding entropy pool\n");
				add_bootloader_randomness(seed->bits, size);
				early_memunmap(seed, sizeof(*seed) + size);
			} else {
				pr_err("Could not map UEFI random seed!\n");
			}
		}
	}

	if (!IS_ENABLED(CONFIG_X86_32) && efi_enabled(EFI_MEMMAP))
		efi_memattr_init();

	efi_tpm_eventlog_init();

	if (mem_reserve != EFI_INVALID_TABLE_ADDR) {
		unsigned long prsv = mem_reserve;

		while (prsv) {
			struct linux_efi_memreserve *rsv;
			u8 *p;

			/*
			 * Just map a full page: that is what we will get
			 * anyway, and it permits us to map the entire entry
			 * before knowing its size.
			 */
			p = early_memremap(ALIGN_DOWN(prsv, PAGE_SIZE),
					   PAGE_SIZE);
			if (p == NULL) {
				pr_err("Could not map UEFI memreserve entry!\n");
				return -ENOMEM;
			}

			rsv = (void *)(p + prsv % PAGE_SIZE);

			/* reserve the entry itself */
			memblock_reserve(prsv,
					 struct_size(rsv, entry, rsv->size));

			for (i = 0; i < atomic_read(&rsv->count); i++) {
				memblock_reserve(rsv->entry[i].base,
						 rsv->entry[i].size);
			}

			prsv = rsv->next;
			early_memunmap(p, PAGE_SIZE);
		}
	}

	if (rt_prop != EFI_INVALID_TABLE_ADDR) {
		efi_rt_properties_table_t *tbl;

		tbl = early_memremap(rt_prop, sizeof(*tbl));
		if (tbl) {
			efi.runtime_supported_mask &= tbl->runtime_services_supported;
			early_memunmap(tbl, sizeof(*tbl));
		}
	}

	return 0;
}