On 5/11/20 8:14 PM, Ilias Apalodimas wrote:
> In OP-TEE we can run EDK2's StandAloneMM on a secure partition.
> StandAloneMM is responsible for the UEFI variable support. In
> combination with OP-TEE and it's U-Boot supplicant, variables are
> authenticated/validated in secure world and stored on an RPMB partition.
>
> So let's add a new config option in U-Boot implementing the necessary
> calls to OP-TEE for the variable management.
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodi...@linaro.org>
> Signed-off-by: Pipat Methavanitpong <pipat1...@gmail.com>
> Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org>
> ---
> lib/efi_loader/Kconfig | 9 +
> lib/efi_loader/Makefile | 4 +
> lib/efi_loader/efi_variable_tee.c | 643 ++++++++++++++++++++++++++++++
> 3 files changed, 656 insertions(+)
> create mode 100644 lib/efi_loader/efi_variable_tee.c
>
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index 1cfa24ffcf72..e385cd0b9dae 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -164,4 +164,13 @@ config EFI_SECURE_BOOT
> it is signed with a trusted key. To do that, you need to install,
> at least, PK, KEK and db.
>
> +config EFI_MM_COMM_TEE
> + bool "UEFI variables storage service via OP-TEE"
> + depends on SUPPORT_EMMC_RPMB
> + default n
> + help
> + If OP-TEE is present and running StandAloneMM dispatch all UEFI
> variable
> + related operations to that. The application will verify, authenticate
> and
> + store the variables on an RPMB
> +
> endif
> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> index eff3c25ec301..dba652121eab 100644
> --- a/lib/efi_loader/Makefile
> +++ b/lib/efi_loader/Makefile
> @@ -34,7 +34,11 @@ obj-y += efi_root_node.o
> obj-y += efi_runtime.o
> obj-y += efi_setup.o
> obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o
> +ifeq ($(CONFIG_EFI_MM_COMM_TEE),y)
> +obj-y += efi_variable_tee.o
> +else
> obj-y += efi_variable.o
> +endif
> obj-y += efi_watchdog.o
> obj-$(CONFIG_LCD) += efi_gop.o
> obj-$(CONFIG_DM_VIDEO) += efi_gop.o
> diff --git a/lib/efi_loader/efi_variable_tee.c
> b/lib/efi_loader/efi_variable_tee.c
> new file mode 100644
> index 000000000000..f8857bb81e72
> --- /dev/null
> +++ b/lib/efi_loader/efi_variable_tee.c
> @@ -0,0 +1,643 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * EFI variable service via OP-TEE
> + *
> + * Copyright (C) 2019 Linaro Ltd. <sughosh.g...@linaro.org>
> + * Copyright (C) 2019 Linaro Ltd. <ilias.apalodi...@linaro.org>
> + */
> +
> +#include <common.h>
> +#include <efi.h>
> +#include <efi_api.h>
> +#include <efi_loader.h>
> +#include <tee.h>
> +#include <malloc.h>
> +#include <mm_communication.h>
> +
> +static efi_uintn_t max_buffer_size; /* comm + var + func + data */
> +static efi_uintn_t max_payload_size; /* func + data */
> +
> +struct mm_connection {
> + struct udevice *tee;
> + u32 session;
> +};
> +
> +/**
> + * get_connection() - Retrieve OP-TEE session for a specific UUID.
> + *
> + * @conn: session buffer to fill
> + * Return: status code
> + */
> +static int get_connection(struct mm_connection *conn)
> +{
> + static const struct tee_optee_ta_uuid uuid = PTA_STMM_UUID;
> + struct udevice *tee = NULL;
> + struct tee_open_session_arg arg;
> + int rc;
> +
> + tee = tee_find_device(tee, NULL, NULL, NULL);
> + if (!tee)
> + return -ENODEV;
> +
> + memset(&arg, 0, sizeof(arg));
> + tee_optee_ta_uuid_to_octets(arg.uuid, &uuid);
> + rc = tee_open_session(tee, &arg, 0, NULL);
> + if (!rc) {
> + conn->tee = tee;
> + conn->session = arg.session;
> + }
> +
> + return rc;
> +}
> +
> +/**
> + * optee_mm_communicate() - Pass a buffer to StandaloneMM running in OP-TEE
> + *
> + * @comm_buf: locally allocted communcation buffer
> + * @dsize: buffer size
> + * Return: status code
> + */
> +static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
> +{
> + ulong buf_size;
> + efi_status_t ret;
> + struct efi_mm_communicate_header *mm_hdr;
> + struct mm_connection conn = { NULL, 0 };
> + struct tee_invoke_arg arg;
> + struct tee_param param[2];
> + struct tee_shm *shm = NULL;
> + int rc;
> +
> + if (!comm_buf)
> + return EFI_INVALID_PARAMETER;
> +
> + mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
> + buf_size = mm_hdr->message_len + sizeof(efi_guid_t) + sizeof(size_t);
> +
> + if (dsize != buf_size)
> + return EFI_INVALID_PARAMETER;
> +
> + rc = get_connection(&conn);
> + if (rc) {
> + log_err("Unable to open OP-TEE session (err=%d)\n", rc);
> + return EFI_UNSUPPORTED;
> + }
> +
> + if (tee_shm_register(conn.tee, comm_buf, buf_size, 0, &shm)) {
> + log_err("Unable to register shared memory\n");
> + return EFI_UNSUPPORTED;
> + }
> +
> + memset(&arg, 0, sizeof(arg));
> + arg.func = PTA_STMM_CMDID_COMMUNICATE;
> + arg.session = conn.session;
> +
> + memset(param, 0, sizeof(param));
> + param[0].attr = TEE_PARAM_ATTR_TYPE_MEMREF_INOUT;
> + param[0].u.memref.size = buf_size;
> + param[0].u.memref.shm = shm;
> + param[1].attr = TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT;
> +
> + rc = tee_invoke_func(conn.tee, &arg, 2, param);
> + if (rc)
> + return EFI_INVALID_PARAMETER;
> + tee_shm_free(shm);
> + tee_close_session(conn.tee, conn.session);
> +
> + switch (param[1].u.value.a) {
> + case ARM_SMC_MM_RET_SUCCESS:
> + ret = EFI_SUCCESS;
> + break;
> +
> + case ARM_SMC_MM_RET_INVALID_PARAMS:
> + ret = EFI_INVALID_PARAMETER;
> + break;
> +
> + case ARM_SMC_MM_RET_DENIED:
> + ret = EFI_ACCESS_DENIED;
> + break;
> +
> + case ARM_SMC_MM_RET_NO_MEMORY:
> + ret = EFI_OUT_OF_RESOURCES;
> + break;
> +
> + default:
> + ret = EFI_ACCESS_DENIED;
> + }
> +
> + return ret;
> +}
> +
> +/**
> + * mm_communicate() - Adjust the cmonnucation buffer to StandAlonneMM and
> send
> + * it to OP-TEE
> + *
> + * @comm_buf: locally allocted communcation buffer
> + * @dsize: buffer size
> + * Return: status code
> + */
> +static efi_status_t mm_communicate(u8 *comm_buf, efi_uintn_t dsize)
> +{
> + efi_status_t ret;
> + struct efi_mm_communicate_header *mm_hdr;
> + struct smm_variable_communicate_header *var_hdr;
> +
> + dsize += MM_COMMUNICATE_HEADER_SIZE + MM_VARIABLE_COMMUNICATE_SIZE;
> + mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
> + var_hdr = (struct smm_variable_communicate_header *)mm_hdr->data;
> +
> + ret = optee_mm_communicate(comm_buf, dsize);
> + if (ret != EFI_SUCCESS) {
> + log_err("%s failed!\n", __func__);
> + return ret;
> + }
> +
> + return var_hdr->ret_status;
> +}
> +
> +/**
> + * setup_mm_hdr() - Allocate a buffer for StandAloneMM and initialize the
> + * header data.
> + *
> + * @dptr: pointer address of the corresponding StandAloneMM
> + * function
> + * @payload_size: buffer size
> + * @func: standAloneMM function number
> + * @ret: EFI return code
> + * Return: buffer or NULL
> + */
> +static u8 *setup_mm_hdr(void **dptr, efi_uintn_t payload_size,
> + efi_uintn_t func, efi_status_t *ret)
> +{
> + const efi_guid_t mm_var_guid = EFI_MM_VARIABLE_GUID;
> + struct efi_mm_communicate_header *mm_hdr;
> + struct smm_variable_communicate_header *var_hdr;
> + u8 *comm_buf;
> +
> + /* In the init function we initialize max_buffer_size with
> + * get_max_payload(). So skip the test if max_buffer_size is initialized
> + * StandAloneMM will perform similar checks and drop the buffer if it's
> + * too long
> + */
> + if (max_buffer_size && max_buffer_size <
> + (MM_COMMUNICATE_HEADER_SIZE +
> + MM_VARIABLE_COMMUNICATE_SIZE +
> + payload_size)) {
> + *ret = EFI_INVALID_PARAMETER;
> + return NULL;
> + }
> +
> + comm_buf = calloc(1, MM_COMMUNICATE_HEADER_SIZE +
> + MM_VARIABLE_COMMUNICATE_SIZE +
> + payload_size);
> + if (!comm_buf) {
> + *ret = EFI_OUT_OF_RESOURCES;
> + return NULL;
> + }
> +
> + mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
> + guidcpy(&mm_hdr->header_guid, &mm_var_guid);
> + mm_hdr->message_len = MM_VARIABLE_COMMUNICATE_SIZE + payload_size;
> +
> + var_hdr = (struct smm_variable_communicate_header *)mm_hdr->data;
> + var_hdr->function = func;
> + if (dptr)
> + *dptr = var_hdr->data;
> + *ret = EFI_SUCCESS;
> +
> + return comm_buf;
> +}
> +
> +/**
> + * get_max_payload() - Get variable payload size from StandAloneMM.
> + *
> + * @size: size of the variable in storage
> + * Return: status code
> + */
> +efi_status_t EFIAPI get_max_payload(efi_uintn_t *size)
> +{
> + struct smm_variable_payload_size *var_payload = NULL;
> + efi_uintn_t payload_size;
> + efi_status_t ret;
> + u8 *comm_buf;
> +
> + if (!size)
> + return EFI_INVALID_PARAMETER;
> +
> + payload_size = sizeof(*var_payload);
> + comm_buf = setup_mm_hdr((void **)&var_payload, payload_size,
> + SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE, &ret);
> + if (!comm_buf)
> + return EFI_EXIT(ret);
> +
> + ret = mm_communicate(comm_buf, payload_size);
> + if (ret != EFI_SUCCESS)
> + goto out;
> +
> + *size = var_payload->size;
> +
> +out:
> + free(comm_buf);
> + return ret;
> +}
> +
> +/**
> + * efi_get_variable() - retrieve value of a UEFI variable
> + *
> + * This function implements the GetVariable runtime service.
> + *
> + * See the Unified Extensible Firmware Interface (UEFI) specification for
> + * details.
> + *
> + * @name: name of the variable
> + * @guid: vendor GUID
> + * @attr: attributes of the variable
> + * @data_size: size of the buffer to which the variable value
> is copied
> + * @data: buffer to which the variable value is copied
> + * Return: status code
> + */
> +efi_status_t EFIAPI efi_get_variable(u16 *name, const efi_guid_t *guid,
> + u32 *attr, efi_uintn_t *data_size,
> + void *data)
> +{
> + struct smm_variable_access *var_acc;
> + efi_uintn_t payload_size;
> + efi_uintn_t name_size;
> + efi_uintn_t tmp_dsize;
> + efi_status_t ret;
> + u8 *comm_buf;
> +
> + EFI_ENTRY("\"%ls\" %pUl %p %p %p", name, guid, attr, data_size, data);
> +
> + if (!name || !guid || !data_size)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> +
> + /* Check payload size */
> + name_size = u16_strsize(name);
> + if (name_size > max_payload_size - MM_VARIABLE_ACCESS_HEADER_SIZE)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> +
> + /* Trim output buffer size */
> + tmp_dsize = *data_size;
> + if (name_size + tmp_dsize >
> + max_payload_size - MM_VARIABLE_ACCESS_HEADER_SIZE) {
> + tmp_dsize = max_payload_size -
> + MM_VARIABLE_ACCESS_HEADER_SIZE -
> + name_size;
> + }
> +
> + /* Get communication buffer and initialize header */
> + payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + tmp_dsize;
> + comm_buf = setup_mm_hdr((void **)&var_acc, payload_size,
> + SMM_VARIABLE_FUNCTION_GET_VARIABLE, &ret);
> + if (!comm_buf)
> + return EFI_EXIT(ret);
> +
> + /* Fill in contents */
> + guidcpy(&var_acc->guid, guid);
> + var_acc->data_size = tmp_dsize;
> + var_acc->name_size = name_size;
> + var_acc->attr = attr ? *attr : 0;
> + memcpy(var_acc->name, name, name_size);
> +
> + /* Communicate */
> + ret = mm_communicate(comm_buf, payload_size);
> + if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
> + /* Update with reported data size for trimmed case */
> + *data_size = var_acc->data_size;
> + }
> + if (ret != EFI_SUCCESS)
> + goto done;
> +
> + if (attr)
> + *attr = var_acc->attr;
> + if (data)
> + memcpy(data, (u8 *)var_acc->name + var_acc->name_size,
> + var_acc->data_size);
> + else
> + ret = EFI_INVALID_PARAMETER;
> +
> +done:
> + free(comm_buf);
> + return EFI_EXIT(ret);
> +}
> +
> +/**
> + * efi_get_next_variable_name() - enumerate the current variable names
> + *
> + * @variable_name_size: size of variable_name buffer in byte
> + * @variable_name: name of uefi variable's name in u16
> + * @guid: vendor's guid
> + *
> + * This function implements the GetNextVariableName service.
> + *
> + * See the Unified Extensible Firmware Interface (UEFI) specification for
> + * details.
> + *
> + * Return: status code
> + */
> +efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t
> *variable_name_size,
> + u16 *variable_name,
> + efi_guid_t *guid)
> +{
> + struct smm_variable_getnext *var_getnext;
> + efi_uintn_t payload_size;
> + efi_uintn_t tmp_dsize;
> + efi_uintn_t name_size;
> + efi_status_t ret;
> + efi_uintn_t out_name_size;
> + efi_uintn_t in_name_size;
> + u8 *comm_buf;
> +
> + EFI_ENTRY("%p \"%ls\" %pUl", variable_name_size, variable_name, guid);
> +
> + if (!variable_name_size || !variable_name || !guid)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> +
> + out_name_size = *variable_name_size;
> + in_name_size = u16_strsize(variable_name);
The UEFI spec requires that EFI_INVALID_PARAMETER should be returned if
there is no '\0' character in the first *variable_name_size words of
variable_name. I think we should add this test here instead of using
max(out_name_size, in_name_size) later in the code.
You are currently calling EFI_EXIT() in many places. Depending on the
level of code optimizations done by the compiler and the debug settings
this may need to unnecessary code size. I suggest to use a single exit
point in each of the functions, e.g.
if (out_name_size > in_name_size) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
...
out:
EFI_EXIT(ret);
}
Best regards
Heinrich
> +
> + name_size = u16_strsize(variable_name);
> + if (name_size > max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> +
> + /* Trim output buffer size */
> + tmp_dsize = *variable_name_size;
> + if (name_size + tmp_dsize >
> + max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE) {
> + tmp_dsize = max_payload_size -
> + MM_VARIABLE_GET_NEXT_HEADER_SIZE -
> + name_size;
> + }
> +
> + payload_size = MM_VARIABLE_GET_NEXT_HEADER_SIZE +
> + max(out_name_size, in_name_size);
> + comm_buf = setup_mm_hdr((void **)&var_getnext, payload_size,
> + SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME,
> + &ret);
> + if (!comm_buf)
> + return EFI_EXIT(ret);
> +
> + /* Fill in contents */
> + guidcpy(&var_getnext->guid, guid);
> + var_getnext->name_size = out_name_size;
> + memcpy(var_getnext->name, variable_name, in_name_size);
> + if (out_name_size > in_name_size) {
> + memset((u8 *)var_getnext->name + in_name_size, 0x0,
> + out_name_size - in_name_size);
> + }
> +
> + /* Communicate */
> + ret = mm_communicate(comm_buf, payload_size);
> + if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
> + /* Update with reported data size for trimmed case */
> + *variable_name_size = var_getnext->name_size;
> + }
> + if (ret != EFI_SUCCESS)
> + goto done;
> +
> + guidcpy(guid, &var_getnext->guid);
> + memcpy(variable_name, (u8 *)var_getnext->name,
> + var_getnext->name_size);
> +
> +done:
> + free(comm_buf);
> + return EFI_EXIT(ret);
> +}
> +
> +/**
> + * efi_set_variable() - set value of a UEFI variable
> + *
> + * This function implements the SetVariable runtime service.
> + *
> + * See the Unified Extensible Firmware Interface (UEFI) specification for
> + * details.
> + *
> + * @name: name of the variable
> + * @guid: vendor GUID
> + * @attr: attributes of the variable
> + * @data_size: size of the buffer with the variable value
> + * @data: buffer with the variable value
> + * Return: status code
> + */
> +efi_status_t EFIAPI efi_set_variable(u16 *name, const efi_guid_t *guid,
> + u32 attr, efi_uintn_t data_size,
> + const void *data)
> +{
> + struct smm_variable_access *var_acc;
> + efi_uintn_t payload_size;
> + efi_uintn_t name_size;
> + efi_status_t ret;
> + u8 *comm_buf;
> +
> + EFI_ENTRY("\"%ls\" %pUl %x %zu %p", name, guid, attr, data_size, data);
> +
> + if (!name || name[0] == 0 || !guid)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> + if (data_size > 0 && !data)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> +
> + /* Check payload size */
> + name_size = u16_strsize(name);
> + payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + data_size;
> + if (payload_size > max_payload_size)
> + return EFI_EXIT(EFI_INVALID_PARAMETER);
> +
> + /* Get communication buffer and initialize header */
> + comm_buf = setup_mm_hdr((void **)&var_acc, payload_size,
> + SMM_VARIABLE_FUNCTION_SET_VARIABLE, &ret);
> + if (!comm_buf)
> + return EFI_EXIT(ret);
> +
> + /* Fill in contents */
> + guidcpy(&var_acc->guid, guid);
> + var_acc->data_size = data_size;
> + var_acc->name_size = name_size;
> + var_acc->attr = attr;
> + memcpy(var_acc->name, name, name_size);
> + memcpy((u8 *)var_acc->name + name_size, data, data_size);
> +
> + /* Communicate */
> + ret = mm_communicate(comm_buf, payload_size);
> + free(comm_buf);
> +
> + return EFI_EXIT(ret);
> +}
> +
> +/**
> + * efi_query_variable_info() - get information about EFI variables
> + *
> + * This function implements the QueryVariableInfo() runtime service.
> + *
> + * See the Unified Extensible Firmware Interface (UEFI) specification for
> + * details.
> + *
> + * @attributes: bitmask to select variables to
> be
> + * queried
> + * @maximum_variable_storage_size: maximum size of storage area for the
> + * selected variable types
> + * @remaining_variable_storage_size: remaining size of storage are for the
> + * selected variable types
> + * @maximum_variable_size: maximum size of a variable of the
> + * selected type
> + * Returns: status code
> + */
> +efi_status_t EFIAPI __efi_runtime
> +efi_query_variable_info(u32 attributes, u64 *max_variable_storage_size,
> + u64 *remain_variable_storage_size,
> + u64 *max_variable_size)
> +{
> + struct smm_variable_query_info *mm_query_info;
> + efi_uintn_t payload_size;
> + efi_status_t ret;
> + u8 *comm_buf;
> +
> + EFI_ENTRY("%x %p %p %p", attributes, max_variable_storage_size,
> + remain_variable_storage_size, max_variable_size);
> +
> + payload_size = sizeof(*mm_query_info);
> + comm_buf = setup_mm_hdr((void **)&mm_query_info, payload_size,
> + SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO,
> + &ret);
> + if (!comm_buf)
> + return EFI_EXIT(ret);
> +
> + mm_query_info->attr = attributes;
> + ret = mm_communicate(comm_buf, payload_size);
> + if (ret != EFI_SUCCESS)
> + goto out;
> + *max_variable_storage_size = mm_query_info->max_variable_storage;
> + *remain_variable_storage_size =
> + mm_query_info->remaining_variable_storage;
> + *max_variable_size = mm_query_info->max_variable_size;
> +
> +out:
> + free(comm_buf);
> + return EFI_EXIT(ret);
> +}
> +
> +/**
> + * efi_get_variable_runtime() - runtime implementation of GetVariable()
> + *
> + * @variable_name: name of the variable
> + * @guid: vendor GUID
> + * @attributes: attributes of the variable
> + * @data_size: size of the buffer to which the variable value
> is copied
> + * @data: buffer to which the variable value is copied
> + * Return: status code
> + */
> +static efi_status_t __efi_runtime EFIAPI
> +efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
> + u32 *attributes, efi_uintn_t *data_size, void *data)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * efi_get_next_variable_name_runtime() - runtime implementation of
> + * GetNextVariable()
> + *
> + * @variable_name_size: size of variable_name buffer in byte
> + * @variable_name: name of uefi variable's name in u16
> + * @guid: vendor's guid
> + * Return: status code
> + */
> +static efi_status_t __efi_runtime EFIAPI
> +efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
> + u16 *variable_name, efi_guid_t *guid)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * efi_query_variable_info() - get information about EFI variables
> + *
> + * This function implements the QueryVariableInfo() runtime service.
> + *
> + * See the Unified Extensible Firmware Interface (UEFI) specification for
> + * details.
> + *
> + * @attributes: bitmask to select variables to
> be
> + * queried
> + * @maximum_variable_storage_size: maximum size of storage area for the
> + * selected variable types
> + * @remaining_variable_storage_size: remaining size of storage are for the
> + * selected variable types
> + * @maximum_variable_size: maximum size of a variable of the
> + * selected type
> + * Return: status code
> + */
> +efi_status_t EFIAPI __efi_runtime
> +efi_query_variable_info_runtime(u32 attributes, u64
> *max_variable_storage_size,
> + u64 *remain_variable_storage_size,
> + u64 *max_variable_size)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * efi_set_variable_runtime() - runtime implementation of SetVariable()
> + *
> + * @variable_name: name of the variable
> + * @guid: vendor GUID
> + * @attributes: attributes of the variable
> + * @data_size: size of the buffer with the variable value
> + * @data: buffer with the variable value
> + * Return: status code
> + */
> +static efi_status_t __efi_runtime EFIAPI
> +efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
> + u32 attributes, efi_uintn_t data_size,
> + const void *data)
> +{
> + return EFI_UNSUPPORTED;
> +}
> +
> +/**
> + * efi_variables_boot_exit_notify() - notify ExitBootServices() is called
> + */
> +void efi_variables_boot_exit_notify(void)
> +{
> + u8 *comm_buf;
> + efi_status_t ret;
> +
> + comm_buf = setup_mm_hdr(NULL, 0,
> + SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE, &ret);
> + if (comm_buf)
> + ret = mm_communicate(comm_buf, 0);
> + else
> + ret = EFI_NOT_FOUND;
> +
> + if (ret != EFI_SUCCESS)
> + log_err("Unable to notify StMM for ExitBootServices\n");
> + free(comm_buf);
> +
> + /* Update runtime service table */
> + efi_runtime_services.query_variable_info =
> + efi_query_variable_info_runtime;
> + efi_runtime_services.get_variable = efi_get_variable_runtime;
> + efi_runtime_services.get_next_variable_name =
> + efi_get_next_variable_name_runtime;
> + efi_runtime_services.set_variable = efi_set_variable_runtime;
> + efi_update_table_header_crc32(&efi_runtime_services.hdr);
> +}
> +
> +/**
> + * efi_init_variables() - initialize variable services
> + *
> + * Return: status code
> + */
> +efi_status_t efi_init_variables(void)
> +{
> + efi_status_t ret;
> +
> + ret = get_max_payload(&max_payload_size);
> + if (ret != EFI_SUCCESS)
> + return ret;
> +
> + max_buffer_size = MM_COMMUNICATE_HEADER_SIZE +
> + MM_VARIABLE_COMMUNICATE_SIZE +
> + max_payload_size;
> +
> + return EFI_SUCCESS;
> +}
>
