[PATCH 2/2 v4] efi: Add basic EFI_TCG2_PROTOCOL support
Heinrich Schuchardt
xypron.glpk at gmx.de
Thu Nov 12 20:26:38 CET 2020
On 11/11/20 10:18 AM, Ilias Apalodimas wrote:
> Since U-boot EFI implementation is getting richer it makes sense to
> add support for EFI_TCG2_PROTOCOL taking advantage of any hardware TPM
> available on the device.
>
> This is the initial implementation of the protocol which only adds
> support for GetCapability(). It's limited in the newer and safer
> TPMv2 devices.
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
> * changes since v3:
> - added check for maximum number of PCRs allowed
> - replaced multiple return Xl with goto out tags
> * changes since v2:
> - added description about include/efi_tcg2.h
> - switch bool to u8 for tpm_present_flag
> - removed superfluous 'default n' from Kconfig
> - use 'goto 'tag' when possible
>
> * changes since v1:
> - change return variable of platform_get_tpm2_device() when used
> - since more headers were included in patch #2 use them in offset
> calculations for all tpm commands
> - change the size of the response buffer regardless of what
> tpm2_get_capability() is doing
> include/efi_loader.h | 2 +
> include/efi_tcg2.h | 94 +++++++
> lib/efi_loader/Kconfig | 7 +
> lib/efi_loader/Makefile | 1 +
> lib/efi_loader/efi_setup.c | 7 +
> lib/efi_loader/efi_tcg2.c | 539 +++++++++++++++++++++++++++++++++++++
> 6 files changed, 650 insertions(+)
> create mode 100644 include/efi_tcg2.h
> create mode 100644 lib/efi_loader/efi_tcg2.c
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index f550ced56876..e5015d865ec9 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -405,6 +405,8 @@ efi_status_t efi_console_register(void);
> efi_status_t efi_disk_register(void);
> /* Called by efi_init_obj_list() to install EFI_RNG_PROTOCOL */
> efi_status_t efi_rng_register(void);
> +/* Called by efi_init_obj_list() to install EFI_TCG2_PROTOCOL */
> +efi_status_t efi_tcg2_register(void);
> /* Create handles and protocols for the partitions of a block device */
> int efi_disk_create_partitions(efi_handle_t parent, struct blk_desc *desc,
> const char *if_typename, int diskid,
> diff --git a/include/efi_tcg2.h b/include/efi_tcg2.h
> new file mode 100644
> index 000000000000..4214f767eaba
> --- /dev/null
> +++ b/include/efi_tcg2.h
> @@ -0,0 +1,94 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Defines data structures and APIs that allow an OS to interact with UEFI
> + * firmware to query information about the device
> + *
> + * Copyright (c) 2020, Linaro Limited
> + */
> +
> +#if !defined _EFI_TCG2_PROTOCOL_H_
> +#define _EFI_TCG2_PROTOCOL_H_
> +
> +#include <tpm-v2.h>
> +
> +#define EFI_TCG2_PROTOCOL_GUID \
> + EFI_GUID(0x607f766c, 0x7455, 0x42be, 0x93, \
> + 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
> +
> +/* TPMV2 only */
> +#define TCG2_EVENT_LOG_FORMAT_TCG_2 0x00000002
> +
> +/* SHA1, SHA256, SHA384, SHA512, TPM_ALG_SM3_256 */
> +#define MAX_HASH_COUNT 5
> +/* Algorithm Registry */
> +#define EFI_TCG2_BOOT_HASH_ALG_SHA1 0x00000001
> +#define EFI_TCG2_BOOT_HASH_ALG_SHA256 0x00000002
> +#define EFI_TCG2_BOOT_HASH_ALG_SHA384 0x00000004
> +#define EFI_TCG2_BOOT_HASH_ALG_SHA512 0x00000008
> +#define EFI_TCG2_BOOT_HASH_ALG_SM3_256 0x00000010
> +
> +typedef u32 efi_tcg_event_log_bitmap;
> +typedef u32 efi_tcg_event_log_format;
> +typedef u32 efi_tcg_event_algorithm_bitmap;
> +
> +struct efi_tcg2_version {
> + u8 major;
> + u8 minor;
> +};
> +
> +struct efi_tcg2_event_header {
> + u32 header_size;
> + u16 header_version;
> + u32 pcr_index;
> + u32 event_type;
> +} __packed;
> +
> +struct efi_tcg2_event {
> + u32 size;
> + struct efi_tcg2_event_header header;
> + u8 event[];
> +} __packed;
> +
> +struct efi_tcg2_boot_service_capability {
> + u8 size;
> + struct efi_tcg2_version structure_version;
> + struct efi_tcg2_version protocol_version;
> + efi_tcg_event_algorithm_bitmap hash_algorithm_bitmap;
> + efi_tcg_event_log_bitmap supported_event_logs;
> + u8 tpm_present_flag;
> + u16 max_command_size;
> + u16 max_response_size;
> + u32 manufacturer_id;
> + u32 number_of_pcr_banks;
> + efi_tcg_event_algorithm_bitmap active_pcr_banks;
> +};
> +
> +#define boot_service_capability_min \
> + sizeof(struct efi_tcg2_boot_service_capability) - \
> + offsetof(struct efi_tcg2_boot_service_capability, number_of_pcr_banks)
> +
> +struct efi_tcg2_protocol {
> + efi_status_t (EFIAPI * get_capability)(struct efi_tcg2_protocol *this,
> + struct efi_tcg2_boot_service_capability *capability);
> + efi_status_t (EFIAPI * get_eventlog)(struct efi_tcg2_protocol *this,
> + efi_tcg_event_log_format log_format,
> + u64 *event_log_location, u64 *event_log_last_entry,
> + bool *event_log_truncated);
> + efi_status_t (EFIAPI * hash_log_extend_event)(struct efi_tcg2_protocol *this,
> + u64 flags, u64 data_to_hash,
> + u64 data_to_hash_len,
> + struct efi_tcg2_event *efi_tcg_event);
> + efi_status_t (EFIAPI * submit_command)(struct efi_tcg2_protocol *this,
> + u32 input_parameter_block_size,
> + u8 *input_parameter_block,
> + u32 output_parameter_block_size,
> + u8 *output_parameter_block);
> + efi_status_t (EFIAPI * get_active_pcr_banks)(struct efi_tcg2_protocol *this,
> + u32 *active_pcr_banks);
> + efi_status_t (EFIAPI * set_active_pcr_banks)(struct efi_tcg2_protocol *this,
> + u32 active_pcr_banks);
> + efi_status_t (EFIAPI * get_result_of_set_active_pcr_banks)(struct efi_tcg2_protocol *this,
> + u32 *operation_present,
> + u32 *response);
> +};
> +#endif
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index 075481428cdf..29ea14b2ee2a 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -184,6 +184,13 @@ config EFI_RNG_PROTOCOL
> Provide a EFI_RNG_PROTOCOL implementation using the hardware random
> number generator of the platform.
>
> +config EFI_TCG2_PROTOCOL
> + bool "EFI_TCG2_PROTOCOL support"
> + depends on TPM_V2
> + help
> + Provide a EFI_TCG2_PROTOCOL implementation using the TPM hardware
> + of the platform.
> +
> config EFI_LOAD_FILE2_INITRD
> bool "EFI_FILE_LOAD2_PROTOCOL for Linux initial ramdisk"
> default n
> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> index 8892fb01e125..cd4b252a417c 100644
> --- a/lib/efi_loader/Makefile
> +++ b/lib/efi_loader/Makefile
> @@ -53,6 +53,7 @@ obj-$(CONFIG_NET) += efi_net.o
> obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o
> obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o
> obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o
> +obj-$(CONFIG_EFI_TCG2_PROTOCOL) += efi_tcg2.o
> obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o
> obj-y += efi_signature.o
>
> diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
> index 45226c5c1a53..e206b60bb82c 100644
> --- a/lib/efi_loader/efi_setup.c
> +++ b/lib/efi_loader/efi_setup.c
> @@ -156,6 +156,13 @@ efi_status_t efi_init_obj_list(void)
> if (ret != EFI_SUCCESS)
> goto out;
> }
> +
> + if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) {
> + ret = efi_tcg2_register();
> + if (ret != EFI_SUCCESS)
> + goto out;
> + }
> +
> /* Initialize variable services */
> ret = efi_init_variables();
> if (ret != EFI_SUCCESS)
> diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c
> new file mode 100644
> index 000000000000..d600cff66af1
> --- /dev/null
> +++ b/lib/efi_loader/efi_tcg2.c
> @@ -0,0 +1,539 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Defines APIs that allow an OS to interact with UEFI firmware to query
> + * information about the device.
> + * https://trustedcomputinggroup.org/resource/tcg-efi-protocol-specification/
> + *
> + * Copyright (c) 2020, Linaro Limited
> + */
> +
> +#define LOG_CATEGORY LOGC_EFI
> +#include <common.h>
> +#include <dm.h>
> +#include <efi_loader.h>
> +#include <efi_tcg2.h>
> +#include <log.h>
> +#include <tpm-v2.h>
> +#include <linux/unaligned/access_ok.h>
> +#include <linux/unaligned/generic.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +/*
> + * When requesting TPM2_CAP_TPM_PROPERTIES the value is on a standard offset.
> + * Since the current tpm2_get_capability() response buffers starts at
> + * 'union tpmu_capabilities data' of 'struct tpms_capability_data', calculate
> + * the response size and offset once for all consumers
> + */
> +#define TPM2_RESPONSE_BUFFER_SIZE (sizeof(struct tpms_capability_data) - \
> + offsetof(struct tpms_capability_data, data))
> +#define properties_offset (offsetof(struct tpml_tagged_tpm_property, tpm_property) + \
> + offsetof(struct tpms_tagged_property, value))
> +
> +const efi_guid_t efi_guid_tcg2_protocol = EFI_TCG2_PROTOCOL_GUID;
> +
> +/**
> + * platform_get_tpm_device() - retrieve TPM device
> + *
> + * This function retrieves the udevice implementing a TPM
> + *
> + * This function may be overridden if special initialization is needed.
> + *
> + * @dev: udevice
> + * Return: status code
> + */
> +__weak efi_status_t platform_get_tpm2_device(struct udevice **dev)
> +{
> + int ret;
> + struct udevice *devp;
> +
> + ret = uclass_get_device(UCLASS_TPM, 0, &devp);
> + if (ret)
> + return EFI_DEVICE_ERROR;
> +
> + *dev = devp;
> +
> + return EFI_SUCCESS;
> +}
> +
> +/**
> + * tpm2_get_max_command_size() - get the supported max command size
> + *
> + * @dev: TPM device
> + * @max_command_size: output buffer for the size
> + *
> + * Return: 0 on success, -1 on error
> + */
> +static int tpm2_get_max_command_size(struct udevice *dev, u16 *max_command_size)
> +{
> + u8 response[TPM2_RESPONSE_BUFFER_SIZE];
> + u32 ret;
> +
> + memset(response, 0, sizeof(response));
> + ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
> + TPM2_PT_MAX_COMMAND_SIZE, response, 1);
> + if (ret)
> + return -1;
> +
> + *max_command_size = (uint16_t)get_unaligned_be32(response +
> + properties_offset);
> +
> + return 0;
> +}
> +
> +/**
> + * tpm2_get_max_response_size() - get the supported max response size
> + *
> + * @dev: TPM device
> + * @max_response_size: output buffer for the size
> + *
> + * Return: 0 on success, -1 on error
> + */
> +static int tpm2_get_max_response_size(struct udevice *dev,
> + u16 *max_response_size)
> +{
> + u8 response[TPM2_RESPONSE_BUFFER_SIZE];
> + u32 ret;
> +
> + memset(response, 0, sizeof(response));
> + ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
> + TPM2_PT_MAX_RESPONSE_SIZE, response, 1);
> + if (ret)
> + return -1;
> +
> + *max_response_size = (uint16_t)get_unaligned_be32(response +
> + properties_offset);
> +
> + return 0;
> +}
> +
> +/**
> + * tpm2_get_manufacturer_id() - get the manufacturer ID
> + *
> + * @dev: TPM device
> + * @manufacturer_id: output buffer for the id
> + *
> + * Return: 0 on success, -1 on error
> + */
> +static int tpm2_get_manufacturer_id(struct udevice *dev, u32 *manufacturer_id)
> +{
> + u8 response[TPM2_RESPONSE_BUFFER_SIZE];
> + u32 ret;
> +
> + memset(response, 0, sizeof(response));
> + ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
> + TPM2_PT_MANUFACTURER, response, 1);
> + if (ret)
> + return -1;
> +
> + *manufacturer_id = get_unaligned_be32(response + properties_offset);
> +
> + return 0;
> +}
> +
> +/**
> + * tpm2_get_num_pcr() - get the number of PCRs
> + *
> + * @dev: TPM device
> + * @manufacturer_id: output buffer for the number
> + *
> + * Return: 0 on success, -1 on error
> + */
> +static int tpm2_get_num_pcr(struct udevice *dev, u32 *num_pcr)
> +{
> + u8 response[TPM2_RESPONSE_BUFFER_SIZE];
> + u32 ret;
> +
> + memset(response, 0, sizeof(response));
> + ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
> + TPM2_PT_PCR_COUNT, response, 1);
> + if (ret)
> + return -1;
> +
> + *num_pcr = get_unaligned_be32(response + properties_offset);
> + if (*num_pcr > TPM2_MAX_PCRS)
> + return -1;
> +
> + return 0;
> +}
> +
> +/**
> + * is_active_pcr() - Check if a supported algorithm is active
> + *
> + * @dev: TPM device
> + * @selection: struct of PCR information
> + *
> + * Return: true if PCR is active
> + */
> +bool is_active_pcr(struct tpms_pcr_selection *selection)
> +{
> + int i;
> + /*
> + * check the pcr_select. If at least one of the PCRs supports the
> + * algorithm add it on the active ones
> + */
> + for (i = 0; i < selection->size_of_select; i++) {
> + if (selection->pcr_select[i])
> + return true;
> + }
> +
> + return false;
> +}
> +
> +/**
> + * tpm2_get_pcr_info() - get the supported, active PCRs and number of banks
> + *
> + * @dev: TPM device
> + * @supported_pcr: bitmask with the algorithms supported
> + * @active_pcr: bitmask with the active algorithms
> + * @pcr_banks: number of PCR banks
> + *
> + * Return: 0 on success, -1 on error
> + */
> +static int tpm2_get_pcr_info(struct udevice *dev, u32 *supported_pcr,
> + u32 *active_pcr, u32 *pcr_banks)
> +{
> + u8 response[TPM2_RESPONSE_BUFFER_SIZE];
> + struct tpml_pcr_selection pcrs;
> + u32 ret, num_pcr;
> + int i, tpm_ret;
> +
> + memset(response, 0, sizeof(response));
> + ret = tpm2_get_capability(dev, TPM2_CAP_PCRS, 0, response, 1);
> + if (ret)
> + goto out;
> +
> + pcrs.count = get_unaligned_be32(response);
> + /*
> + * We only support 5 algorithms for now so check against that
> + * instead of TPM2_NUM_PCR_BANKS
> + */
> + if (pcrs.count > MAX_HASH_COUNT || pcrs.count < 1)
> + goto out;
> +
> + tpm_ret = tpm2_get_num_pcr(dev, &num_pcr);
> + if (tpm_ret)
> + goto out;
> +
> + for (i = 0; i < pcrs.count; i++) {
> + /*
> + * Definition of TPMS_PCR_SELECTION Structure
> + * hash: u16
> + * size_of_select: u8
> + * pcr_select: u8 array
> + *
> + * The offsets depend on the number of the device PCRs
> + * so we have to calculate them based on that
> + */
> + u32 hash_offset = offsetof(struct tpml_pcr_selection, selection) +
> + i * offsetof(struct tpms_pcr_selection, pcr_select) +
> + i * ((num_pcr + 7) / 8);
> + u32 size_select_offset =
> + hash_offset + offsetof(struct tpms_pcr_selection,
> + size_of_select);
> + u32 pcr_select_offset =
> + hash_offset + offsetof(struct tpms_pcr_selection,
> + pcr_select);
> +
> + pcrs.selection[i].hash =
> + get_unaligned_be16(response + hash_offset);
> + pcrs.selection[i].size_of_select =
> + __get_unaligned_be(response + size_select_offset);
> + if (pcrs.selection[i].size_of_select > TPM2_PCR_SELECT_MAX)
> + goto out;
> + /* copy the array of pcr_select */
> + memcpy(pcrs.selection[i].pcr_select, response + pcr_select_offset,
> + pcrs.selection[i].size_of_select);
> + }
> +
> + for (i = 0; i < pcrs.count; i++) {
> + switch (pcrs.selection[i].hash) {
> + case TPM2_ALG_SHA1:
> + *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA1;
> + if (is_active_pcr(&pcrs.selection[i]))
> + *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA1;
> + break;
> + case TPM2_ALG_SHA256:
> + *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA256;
> + if (is_active_pcr(&pcrs.selection[i]))
> + *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA256;
> + break;
> + case TPM2_ALG_SHA384:
> + *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA384;
> + if (is_active_pcr(&pcrs.selection[i]))
> + *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA384;
> + break;
> + case TPM2_ALG_SHA512:
> + *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA512;
> + if (is_active_pcr(&pcrs.selection[i]))
> + *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SHA512;
> + break;
> + case TPM2_ALG_SM3_256:
> + *supported_pcr |= EFI_TCG2_BOOT_HASH_ALG_SM3_256;
> + if (is_active_pcr(&pcrs.selection[i]))
> + *active_pcr |= EFI_TCG2_BOOT_HASH_ALG_SM3_256;
> + break;
> + default:
> + EFI_PRINT("Unknown algorithm %x\n",
> + pcrs.selection[i].hash);
> + break;
> + }
> + }
> +
> + *pcr_banks = pcrs.count;
> +
> + return 0;
> +out:
> + return -1;
> +}
> +
> +/**
> + * get_capability() - protocol capability information and state information
> + *
> + * @this: TCG2 protocol instance
> + * @capability: caller allocated memory with size field to the size of
> + * the structure allocated
> +
> + * Return: status code
> + */
> +static efi_status_t EFIAPI
> +get_capability(struct efi_tcg2_protocol *this,
Please, use unique function names. That makes setting breakpoints in gdb
much easier. How about: efi_tcg2_get_capability()?
Same for all other functions.
Regards
Heinrich
> + struct efi_tcg2_boot_service_capability *capability)
> +{
> + struct udevice *dev;
> + efi_status_t efi_ret;
> + int ret;
> +
> + EFI_ENTRY("%p, %p", this, capability);
> +
> + if (!this || !capability) {
> + efi_ret = EFI_INVALID_PARAMETER;
> + goto out;
> + }
> +
> + if (capability->size < boot_service_capability_min) {
> + capability->size = boot_service_capability_min;
> + efi_ret = EFI_BUFFER_TOO_SMALL;
> + goto out;
> + }
> +
> + if (capability->size < sizeof(*capability)) {
> + capability->size = sizeof(*capability);
> + efi_ret = EFI_BUFFER_TOO_SMALL;
> + goto out;
> + }
> +
> + capability->structure_version.major = 1;
> + capability->structure_version.minor = 1;
> + capability->protocol_version.major = 1;
> + capability->protocol_version.minor = 1;
> +
> + efi_ret = platform_get_tpm2_device(&dev);
> + if (efi_ret != EFI_SUCCESS) {
> + capability->supported_event_logs = 0;
> + capability->hash_algorithm_bitmap = 0;
> + capability->tpm_present_flag = false;
> + capability->max_command_size = 0;
> + capability->max_response_size = 0;
> + capability->manufacturer_id = 0;
> + capability->number_of_pcr_banks = 0;
> + capability->active_pcr_banks = 0;
> +
> + efi_ret = EFI_SUCCESS;
> + goto out;
> + }
> +
> + /* We only allow a TPMv2 device to register the EFI protocol */
> + capability->supported_event_logs = TCG2_EVENT_LOG_FORMAT_TCG_2;
> +
> + capability->tpm_present_flag = true;
> +
> + /* Supported and active PCRs */
> + capability->hash_algorithm_bitmap = 0;
> + capability->active_pcr_banks = 0;
> + ret = tpm2_get_pcr_info(dev, &capability->hash_algorithm_bitmap,
> + &capability->active_pcr_banks,
> + &capability->number_of_pcr_banks);
> + if (ret) {
> + efi_ret = EFI_DEVICE_ERROR;
> + goto out;
> + }
> +
> + /* Max command size */
> + ret = tpm2_get_max_command_size(dev, &capability->max_command_size);
> + if (ret) {
> + efi_ret = EFI_DEVICE_ERROR;
> + goto out;
> + }
> +
> + /* Max response size */
> + ret = tpm2_get_max_response_size(dev, &capability->max_response_size);
> + if (ret) {
> + efi_ret = EFI_DEVICE_ERROR;
> + goto out;
> + }
> +
> + /* Manufacturer ID */
> + ret = tpm2_get_manufacturer_id(dev, &capability->manufacturer_id);
> + if (ret) {
> + efi_ret = EFI_DEVICE_ERROR;
> + goto out;
> + }
> +
> + return EFI_EXIT(EFI_SUCCESS);
> +out:
> + return EFI_EXIT(efi_ret);
> +}
> +
> +/**
> + * get_eventlog() - retrieve the the address of an event log and its last entry
> + *
> + * @this: TCG2 protocol instance
> + * @log_format: type of event log format
> + * @event_log_location: pointer to the memory address of the event log
> + * @event_log_last_entry: pointer to the address of the start of the last
> + * entry in the event log in memory, if log contains
> + * more than 1 entry
> + * @event_log_truncated: set to true, if the Event Log is missing at i
> + * least one entry
> + *
> + * Return: status code
> + */
> +static efi_status_t EFIAPI
> +get_eventlog(struct efi_tcg2_protocol *this,
> + efi_tcg_event_log_format log_format, u64 *event_log_location,
> + u64 *event_log_last_entry, bool *event_log_truncated)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * hash_log_extend_event()- extend and optionally log events
> + *
> + * @this: TCG2 protocol instance
> + * @flags: bitmap providing additional information on the
> + * operation
> + * @data_to_hash: physical address of the start of the data buffer
> + * to be hashed
> + * @data_to_hash_len: the length in bytes of the buffer referenced by
> + * data_to_hash
> + * @efi_tcg_event: pointer to data buffer containing information
> + * about the event
> + *
> + * Return: status code
> + */
> +static efi_status_t EFIAPI
> +hash_log_extend_event(struct efi_tcg2_protocol *this, u64 flags,
> + u64 data_to_hash, u64 data_to_hash_len,
> + struct efi_tcg2_event *efi_tcg_event)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * submit_command() - Send command to the TPM
> + *
> + * @this: TCG2 protocol instance
> + * @input_param_block_size: size of the TPM input parameter block
> + * @input_param_block: pointer to the TPM input parameter block
> + * @output_param_block_size: size of the TPM output parameter block
> + * @output_param_block: pointer to the TPM output parameter block
> + *
> + * Return: status code
> + */
> +efi_status_t EFIAPI
> +submit_command(struct efi_tcg2_protocol *this, u32 input_param_block_size,
> + u8 *input_param_block, u32 output_param_block_size,
> + u8 *output_param_block)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * get_active_pcr_banks() - returns the currently active PCR banks
> + *
> + * @this: TCG2 protocol instance
> + * @active_pcr_banks: pointer for receiving the bitmap of currently
> + * active PCR banks
> + *
> + * Return: status code
> + */
> +efi_status_t EFIAPI
> +get_active_pcr_banks(struct efi_tcg2_protocol *this, u32 *active_pcr_banks)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * set_active_pcr_banks() - sets the currently active PCR banks
> + *
> + * @this: TCG2 protocol instance
> + * @active_pcr_banks: bitmap of the requested active PCR banks
> + *
> + * Return: status code
> + */
> +efi_status_t EFIAPI
> +set_active_pcr_banks(struct efi_tcg2_protocol *this, u32 active_pcr_banks)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * get_result_of_set_active_pcr_banks() - retrieves the result of a previous
> + * set_active_pcr_banks()
> + *
> + * @this: TCG2 protocol instance
> + * @operation_present: non-zero value to indicate a
> + * set_active_pcr_banks operation was
> + * invoked during last boot
> + * @response: result value could be returned
> + *
> + * Return: status code
> + */
> +efi_status_t EFIAPI
> +get_result_of_set_active_pcr_banks(struct efi_tcg2_protocol *this,
> + u32 *operation_present, u32 *response)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +static const struct efi_tcg2_protocol efi_tcg2_protocol = {
> + .get_capability = get_capability,
> + .get_eventlog = get_eventlog,
> + .hash_log_extend_event = hash_log_extend_event,
> + .submit_command = submit_command,
> + .get_active_pcr_banks = get_active_pcr_banks,
> + .set_active_pcr_banks = set_active_pcr_banks,
> + .get_result_of_set_active_pcr_banks = get_result_of_set_active_pcr_banks,
> +};
> +
> +/**
> + * efi_tcg2_register() - register EFI_TCG2_PROTOCOL
> + *
> + * If a TPM2 device is available, the TPM TCG2 Protocol is registered
> + *
> + * Return: An error status is only returned if adding the protocol fails.
> + */
> +efi_status_t efi_tcg2_register(void)
> +{
> + efi_status_t ret;
> + struct udevice *dev;
> + enum tpm_version tpm_ver;
> +
> + ret = platform_get_tpm2_device(&dev);
> + if (ret != EFI_SUCCESS)
> + return EFI_SUCCESS;
> +
> + tpm_ver = tpm_get_version(dev);
> + if (tpm_ver != TPM_V2) {
> + log_warning("Only TPMv2 supported for EFI_TCG2_PROTOCOL");
> + return EFI_SUCCESS;
> + }
> +
> + ret = efi_add_protocol(efi_root, &efi_guid_tcg2_protocol,
> + (void *)&efi_tcg2_protocol);
> + if (ret != EFI_SUCCESS)
> + log_err("Cannot install EFI_TCG2_PROTOCOL");
> +
> + return ret;
> +}
>
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