Commit 5d288dbd authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

efi: Make rng_seed table handling local to efi.c 



Move the rng_seed table address from struct efi into a static global
variable in efi.c, which is the only place we ever refer to it anyway.
This reduces the footprint of struct efi, which is a r/w data structure
that is shared with the world.

Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent fd506e0c

drivers/firmware/efi/efi.c

+10 −11
Original line number Diff line number Diff line
@@ -44,13 +44,14 @@ struct efi __read_mostly efi = { 
	.config_table		= EFI_INVALID_TABLE_ADDR,

	.esrt			= EFI_INVALID_TABLE_ADDR,

	.mem_attr_table		= EFI_INVALID_TABLE_ADDR,

	.rng_seed		= EFI_INVALID_TABLE_ADDR,

	.tpm_log		= EFI_INVALID_TABLE_ADDR,

	.tpm_final_log		= EFI_INVALID_TABLE_ADDR,

	.mem_reserve		= EFI_INVALID_TABLE_ADDR,

};

EXPORT_SYMBOL(efi);



static unsigned long __ro_after_init rng_seed = EFI_INVALID_TABLE_ADDR;



struct mm_struct efi_mm = {

	.mm_rb			= RB_ROOT,

	.mm_users		= ATOMIC_INIT(2),
@@ -467,7 +468,7 @@ static __initdata efi_config_table_type_t common_tables[] = { 
	{SMBIOS3_TABLE_GUID, "SMBIOS 3.0", &efi.smbios3},

	{EFI_SYSTEM_RESOURCE_TABLE_GUID, "ESRT", &efi.esrt},

	{EFI_MEMORY_ATTRIBUTES_TABLE_GUID, "MEMATTR", &efi.mem_attr_table},

	{LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &efi.rng_seed},

	{LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &rng_seed},

	{LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log},

	{LINUX_EFI_TPM_FINAL_LOG_GUID, "TPMFinalLog", &efi.tpm_final_log},

	{LINUX_EFI_MEMRESERVE_TABLE_GUID, "MEMRESERVE", &efi.mem_reserve},
@@ -535,11 +536,11 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, 
	pr_cont("\n");

	set_bit(EFI_CONFIG_TABLES, &efi.flags);



	if (efi.rng_seed != EFI_INVALID_TABLE_ADDR) {

	if (rng_seed != EFI_INVALID_TABLE_ADDR) {

		struct linux_efi_random_seed *seed;

		u32 size = 0;



		seed = early_memremap(efi.rng_seed, sizeof(*seed));

		seed = early_memremap(rng_seed, sizeof(*seed));

		if (seed != NULL) {

			size = seed->size;

			early_memunmap(seed, sizeof(*seed));
@@ -547,8 +548,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, 
			pr_err("Could not map UEFI random seed!\n");

		}

		if (size > 0) {

			seed = early_memremap(efi.rng_seed,

					      sizeof(*seed) + size);

			seed = early_memremap(rng_seed, sizeof(*seed) + size);

			if (seed != NULL) {

				pr_notice("seeding entropy pool\n");

				add_bootloader_randomness(seed->bits, seed->size);
@@ -1048,7 +1048,7 @@ static int update_efi_random_seed(struct notifier_block *nb, 
	if (!kexec_in_progress)

		return NOTIFY_DONE;



	seed = memremap(efi.rng_seed, sizeof(*seed), MEMREMAP_WB);

	seed = memremap(rng_seed, sizeof(*seed), MEMREMAP_WB);

	if (seed != NULL) {

		size = min(seed->size, EFI_RANDOM_SEED_SIZE);

		memunmap(seed);
@@ -1056,8 +1056,7 @@ static int update_efi_random_seed(struct notifier_block *nb, 
		pr_err("Could not map UEFI random seed!\n");

	}

	if (size > 0) {

		seed = memremap(efi.rng_seed, sizeof(*seed) + size,

				MEMREMAP_WB);

		seed = memremap(rng_seed, sizeof(*seed) + size, MEMREMAP_WB);

		if (seed != NULL) {

			seed->size = size;

			get_random_bytes(seed->bits, seed->size);
@@ -1073,9 +1072,9 @@ static struct notifier_block efi_random_seed_nb = { 
	.notifier_call = update_efi_random_seed,

};



static int register_update_efi_random_seed(void)

static int __init register_update_efi_random_seed(void)

{

	if (efi.rng_seed == EFI_INVALID_TABLE_ADDR)

	if (rng_seed == EFI_INVALID_TABLE_ADDR)

		return 0;

	return register_reboot_notifier(&efi_random_seed_nb);

}

include/linux/efi.h

+0 −1
Original line number Diff line number Diff line
@@ -540,7 +540,6 @@ extern struct efi { 
	unsigned long config_table;	/* config tables */

	unsigned long esrt;		/* ESRT table */

	unsigned long mem_attr_table;	/* memory attributes table */

	unsigned long rng_seed;		/* UEFI firmware random seed */

	unsigned long tpm_log;		/* TPM2 Event Log table */

	unsigned long tpm_final_log;	/* TPM2 Final Events Log table */

	unsigned long mem_reserve;	/* Linux EFI memreserve table */

CRA Git | Maintained and supported by SUSTech CRA and CCSE