1 files changed, 616 insertions, 0 deletions

diff --git a/drivers/firmware/efi/stmm/tee_stmm_efi.c b/drivers/firmware/efi/stmm/tee_stmm_efi.c
new file mode 100644
index 000000000000..f741ca279052
--- /dev/null
+++ b/drivers/firmware/efi/stmm/tee_stmm_efi.c
@@ -0,0 +1,616 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  EFI variable service via TEE
+ *
+ *  Copyright (C) 2022 Linaro
+ */
+
+#include <linux/efi.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/tee.h>
+#include <linux/tee_drv.h>
+#include <linux/ucs2_string.h>
+#include "mm_communication.h"
+
+static struct efivars tee_efivars;
+static struct efivar_operations tee_efivar_ops;
+
+static size_t max_buffer_size; /* comm + var + func + data */
+static size_t max_payload_size; /* func + data */
+
+struct tee_stmm_efi_private {
+	struct tee_context *ctx;
+	u32 session;
+	struct device *dev;
+};
+
+static struct tee_stmm_efi_private pvt_data;
+
+/* UUID of the stmm PTA */
+static const struct tee_client_device_id tee_stmm_efi_id_table[] = {
+	{PTA_STMM_UUID},
+	{}
+};
+
+static int tee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
+{
+	/* currently only OP-TEE is supported as a communication path */
+	if (ver->impl_id == TEE_IMPL_ID_OPTEE)
+		return 1;
+	else
+		return 0;
+}
+
+/**
+ * tee_mm_communicate() - Pass a buffer to StandaloneMM running in TEE
+ *
+ * @comm_buf:		locally allocated communication buffer
+ * @dsize:		buffer size
+ * Return:		status code
+ */
+static efi_status_t tee_mm_communicate(void *comm_buf, size_t dsize)
+{
+	size_t buf_size;
+	struct efi_mm_communicate_header *mm_hdr;
+	struct tee_ioctl_invoke_arg arg;
+	struct tee_param param[4];
+	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;
+
+	shm = tee_shm_register_kernel_buf(pvt_data.ctx, comm_buf, buf_size);
+	if (IS_ERR(shm)) {
+		dev_err(pvt_data.dev, "Unable to register shared memory\n");
+		return EFI_UNSUPPORTED;
+	}
+
+	memset(&arg, 0, sizeof(arg));
+	arg.func = PTA_STMM_CMD_COMMUNICATE;
+	arg.session = pvt_data.session;
+	arg.num_params = 4;
+
+	memset(param, 0, sizeof(param));
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT;
+	param[0].u.memref.size = buf_size;
+	param[0].u.memref.shm = shm;
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
+	param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
+	param[3].attr = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
+
+	rc = tee_client_invoke_func(pvt_data.ctx, &arg, param);
+	tee_shm_free(shm);
+
+	if (rc < 0 || arg.ret != 0) {
+		dev_err(pvt_data.dev,
+			"PTA_STMM_CMD_COMMUNICATE invoke error: 0x%x\n", arg.ret);
+		return EFI_DEVICE_ERROR;
+	}
+
+	switch (param[1].u.value.a) {
+	case ARM_SVC_SPM_RET_SUCCESS:
+		return EFI_SUCCESS;
+
+	case ARM_SVC_SPM_RET_INVALID_PARAMS:
+		return EFI_INVALID_PARAMETER;
+
+	case ARM_SVC_SPM_RET_DENIED:
+		return EFI_ACCESS_DENIED;
+
+	case ARM_SVC_SPM_RET_NO_MEMORY:
+		return EFI_OUT_OF_RESOURCES;
+
+	default:
+		return EFI_ACCESS_DENIED;
+	}
+}
+
+/**
+ * mm_communicate() - Adjust the communication buffer to StandAlonneMM and send
+ * it to TEE
+ *
+ * @comm_buf:		locally allocated communication buffer, buffer should
+ *			be enough big to have some headers and payload
+ * @payload_size:	payload size
+ * Return:		status code
+ */
+static efi_status_t mm_communicate(u8 *comm_buf, size_t payload_size)
+{
+	size_t dsize;
+	efi_status_t ret;
+	struct efi_mm_communicate_header *mm_hdr;
+	struct smm_variable_communicate_header *var_hdr;
+
+	dsize = payload_size + 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 = tee_mm_communicate(comm_buf, dsize);
+	if (ret != EFI_SUCCESS) {
+		dev_err(pvt_data.dev, "%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 to store allocated buffer
+ * @payload_size:	payload size
+ * @func:		standAloneMM function number
+ * @ret:		EFI return code
+ * Return:		pointer to corresponding StandAloneMM function buffer or NULL
+ */
+static void *setup_mm_hdr(u8 **dptr, size_t payload_size, size_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 = kzalloc(MM_COMMUNICATE_HEADER_SIZE +
+				   MM_VARIABLE_COMMUNICATE_SIZE + payload_size,
+			   GFP_KERNEL);
+	if (!comm_buf) {
+		*ret = EFI_OUT_OF_RESOURCES;
+		return NULL;
+	}
+
+	mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
+	memcpy(&mm_hdr->header_guid, &mm_var_guid, sizeof(mm_hdr->header_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 = comm_buf;
+	*ret = EFI_SUCCESS;
+
+	return var_hdr->data;
+}
+
+/**
+ * get_max_payload() - Get variable payload size from StandAloneMM.
+ *
+ * @size:    size of the variable in storage
+ * Return:   status code
+ */
+static efi_status_t get_max_payload(size_t *size)
+{
+	struct smm_variable_payload_size *var_payload = NULL;
+	size_t payload_size;
+	u8 *comm_buf = NULL;
+	efi_status_t ret;
+
+	if (!size)
+		return EFI_INVALID_PARAMETER;
+
+	payload_size = sizeof(*var_payload);
+	var_payload = setup_mm_hdr(&comm_buf, payload_size,
+				   SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE,
+				   &ret);
+	if (!var_payload)
+		return EFI_OUT_OF_RESOURCES;
+
+	ret = mm_communicate(comm_buf, payload_size);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	/* Make sure the buffer is big enough for storing variables */
+	if (var_payload->size < MM_VARIABLE_ACCESS_HEADER_SIZE + 0x20) {
+		ret = EFI_DEVICE_ERROR;
+		goto out;
+	}
+	*size = var_payload->size;
+	/*
+	 * There seems to be a bug in EDK2 miscalculating the boundaries and
+	 * size checks, so deduct 2 more bytes to fulfill this requirement. Fix
+	 * it up here to ensure backwards compatibility with older versions
+	 * (cf. StandaloneMmPkg/Drivers/StandaloneMmCpu/AArch64/EventHandle.c.
+	 * sizeof (EFI_MM_COMMUNICATE_HEADER) instead the size minus the
+	 * flexible array member).
+	 *
+	 * size is guaranteed to be > 2 due to checks on the beginning.
+	 */
+	*size -= 2;
+out:
+	kfree(comm_buf);
+	return ret;
+}
+
+static efi_status_t get_property_int(u16 *name, size_t name_size,
+				     const efi_guid_t *vendor,
+				     struct var_check_property *var_property)
+{
+	struct smm_variable_var_check_property *smm_property;
+	size_t payload_size;
+	u8 *comm_buf = NULL;
+	efi_status_t ret;
+
+	memset(var_property, 0, sizeof(*var_property));
+	payload_size = sizeof(*smm_property) + name_size;
+	if (payload_size > max_payload_size)
+		return EFI_INVALID_PARAMETER;
+
+	smm_property = setup_mm_hdr(
+		&comm_buf, payload_size,
+		SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET, &ret);
+	if (!smm_property)
+		return EFI_OUT_OF_RESOURCES;
+
+	memcpy(&smm_property->guid, vendor, sizeof(smm_property->guid));
+	smm_property->name_size = name_size;
+	memcpy(smm_property->name, name, name_size);
+
+	ret = mm_communicate(comm_buf, payload_size);
+	/*
+	 * Currently only R/O property is supported in StMM.
+	 * Variables that are not set to R/O will not set the property in StMM
+	 * and the call will return EFI_NOT_FOUND. We are setting the
+	 * properties to 0x0 so checking against that is enough for the
+	 * EFI_NOT_FOUND case.
+	 */
+	if (ret == EFI_NOT_FOUND)
+		ret = EFI_SUCCESS;
+	if (ret != EFI_SUCCESS)
+		goto out;
+	memcpy(var_property, &smm_property->property, sizeof(*var_property));
+
+out:
+	kfree(comm_buf);
+	return ret;
+}
+
+static efi_status_t tee_get_variable(u16 *name, efi_guid_t *vendor,
+				     u32 *attributes, unsigned long *data_size,
+				     void *data)
+{
+	struct var_check_property var_property;
+	struct smm_variable_access *var_acc;
+	size_t payload_size;
+	size_t name_size;
+	size_t tmp_dsize;
+	u8 *comm_buf = NULL;
+	efi_status_t ret;
+
+	if (!name || !vendor || !data_size)
+		return EFI_INVALID_PARAMETER;
+
+	name_size = (ucs2_strnlen(name, EFI_VAR_NAME_LEN) + 1) * sizeof(u16);
+	if (name_size > max_payload_size - MM_VARIABLE_ACCESS_HEADER_SIZE)
+		return 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;
+	}
+
+	payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + tmp_dsize;
+	var_acc = setup_mm_hdr(&comm_buf, payload_size,
+			       SMM_VARIABLE_FUNCTION_GET_VARIABLE, &ret);
+	if (!var_acc)
+		return EFI_OUT_OF_RESOURCES;
+
+	/* Fill in contents */
+	memcpy(&var_acc->guid, vendor, sizeof(var_acc->guid));
+	var_acc->data_size = tmp_dsize;
+	var_acc->name_size = name_size;
+	var_acc->attr = attributes ? *attributes : 0;
+	memcpy(var_acc->name, name, name_size);
+
+	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 out;
+
+	ret = get_property_int(name, name_size, vendor, &var_property);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	if (attributes)
+		*attributes = var_acc->attr;
+
+	if (!data) {
+		ret = EFI_INVALID_PARAMETER;
+		goto out;
+	}
+	memcpy(data, (u8 *)var_acc->name + var_acc->name_size,
+	       var_acc->data_size);
+out:
+	kfree(comm_buf);
+	return ret;
+}
+
+static efi_status_t tee_get_next_variable(unsigned long *name_size,
+					  efi_char16_t *name, efi_guid_t *guid)
+{
+	struct smm_variable_getnext *var_getnext;
+	size_t payload_size;
+	size_t out_name_size;
+	size_t in_name_size;
+	u8 *comm_buf = NULL;
+	efi_status_t ret;
+
+	if (!name_size || !name || !guid)
+		return EFI_INVALID_PARAMETER;
+
+	out_name_size = *name_size;
+	in_name_size = (ucs2_strnlen(name, EFI_VAR_NAME_LEN) + 1) * sizeof(u16);
+
+	if (out_name_size < in_name_size)
+		return EFI_INVALID_PARAMETER;
+
+	if (in_name_size > max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE)
+		return EFI_INVALID_PARAMETER;
+
+	/* Trim output buffer size */
+	if (out_name_size > max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE)
+		out_name_size =
+			max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE;
+
+	payload_size = MM_VARIABLE_GET_NEXT_HEADER_SIZE + out_name_size;
+	var_getnext = setup_mm_hdr(&comm_buf, payload_size,
+				   SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME,
+				   &ret);
+	if (!var_getnext)
+		return EFI_OUT_OF_RESOURCES;
+
+	/* Fill in contents */
+	memcpy(&var_getnext->guid, guid, sizeof(var_getnext->guid));
+	var_getnext->name_size = out_name_size;
+	memcpy(var_getnext->name, name, in_name_size);
+	memset((u8 *)var_getnext->name + in_name_size, 0x0,
+	       out_name_size - in_name_size);
+
+	ret = mm_communicate(comm_buf, payload_size);
+	if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
+		/* Update with reported data size for trimmed case */
+		*name_size = var_getnext->name_size;
+	}
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	memcpy(guid, &var_getnext->guid, sizeof(*guid));
+	memcpy(name, var_getnext->name, var_getnext->name_size);
+
+out:
+	kfree(comm_buf);
+	return ret;
+}
+
+static efi_status_t tee_set_variable(efi_char16_t *name, efi_guid_t *vendor,
+				     u32 attributes, unsigned long data_size,
+				     void *data)
+{
+	efi_status_t ret;
+	struct var_check_property var_property;
+	struct smm_variable_access *var_acc;
+	size_t payload_size;
+	size_t name_size;
+	u8 *comm_buf = NULL;
+
+	if (!name || name[0] == 0 || !vendor)
+		return EFI_INVALID_PARAMETER;
+
+	if (data_size > 0 && !data)
+		return EFI_INVALID_PARAMETER;
+
+	/* Check payload size */
+	name_size = (ucs2_strnlen(name, EFI_VAR_NAME_LEN) + 1) * sizeof(u16);
+	payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + data_size;
+	if (payload_size > max_payload_size)
+		return EFI_INVALID_PARAMETER;
+
+	/*
+	 * Allocate the buffer early, before switching to RW (if needed)
+	 * so we won't need to account for any failures in reading/setting
+	 * the properties, if the allocation fails
+	 */
+	var_acc = setup_mm_hdr(&comm_buf, payload_size,
+			       SMM_VARIABLE_FUNCTION_SET_VARIABLE, &ret);
+	if (!var_acc)
+		return EFI_OUT_OF_RESOURCES;
+
+	/*
+	 * The API has the ability to override RO flags. If no RO check was
+	 * requested switch the variable to RW for the duration of this call
+	 */
+	ret = get_property_int(name, name_size, vendor, &var_property);
+	if (ret != EFI_SUCCESS) {
+		dev_err(pvt_data.dev, "Getting variable property failed\n");
+		goto out;
+	}
+
+	if (var_property.property & VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY) {
+		ret = EFI_WRITE_PROTECTED;
+		goto out;
+	}
+
+	/* Fill in contents */
+	memcpy(&var_acc->guid, vendor, sizeof(var_acc->guid));
+	var_acc->data_size = data_size;
+	var_acc->name_size = name_size;
+	var_acc->attr = attributes;
+	memcpy(var_acc->name, name, name_size);
+	memcpy((u8 *)var_acc->name + name_size, data, data_size);
+
+	ret = mm_communicate(comm_buf, payload_size);
+	dev_dbg(pvt_data.dev, "Set Variable %s %d %lx\n", __FILE__, __LINE__, ret);
+out:
+	kfree(comm_buf);
+	return ret;
+}
+
+static efi_status_t tee_set_variable_nonblocking(efi_char16_t *name,
+						 efi_guid_t *vendor,
+						 u32 attributes,
+						 unsigned long data_size,
+						 void *data)
+{
+	return EFI_UNSUPPORTED;
+}
+
+static efi_status_t tee_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;
+	size_t payload_size;
+	efi_status_t ret;
+	u8 *comm_buf;
+
+	payload_size = sizeof(*mm_query_info);
+	mm_query_info = setup_mm_hdr(&comm_buf, payload_size,
+				SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO,
+				&ret);
+	if (!mm_query_info)
+		return EFI_OUT_OF_RESOURCES;
+
+	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:
+	kfree(comm_buf);
+	return ret;
+}
+
+static void tee_stmm_efi_close_context(void *data)
+{
+	tee_client_close_context(pvt_data.ctx);
+}
+
+static void tee_stmm_efi_close_session(void *data)
+{
+	tee_client_close_session(pvt_data.ctx, pvt_data.session);
+}
+
+static void tee_stmm_restore_efivars_generic_ops(void)
+{
+	efivars_unregister(&tee_efivars);
+	efivars_generic_ops_register();
+}
+
+static int tee_stmm_efi_probe(struct device *dev)
+{
+	struct tee_ioctl_open_session_arg sess_arg;
+	efi_status_t ret;
+	int rc;
+
+	pvt_data.ctx = tee_client_open_context(NULL, tee_ctx_match, NULL, NULL);
+	if (IS_ERR(pvt_data.ctx))
+		return -ENODEV;
+
+	rc = devm_add_action_or_reset(dev, tee_stmm_efi_close_context, NULL);
+	if (rc)
+		return rc;
+
+	/* Open session with StMM PTA */
+	memset(&sess_arg, 0, sizeof(sess_arg));
+	export_uuid(sess_arg.uuid, &tee_stmm_efi_id_table[0].uuid);
+	rc = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL);
+	if ((rc < 0) || (sess_arg.ret != 0)) {
+		dev_err(dev, "tee_client_open_session failed, err: %x\n",
+			sess_arg.ret);
+		return -EINVAL;
+	}
+	pvt_data.session = sess_arg.session;
+	pvt_data.dev = dev;
+	rc = devm_add_action_or_reset(dev, tee_stmm_efi_close_session, NULL);
+	if (rc)
+		return rc;
+
+	ret = get_max_payload(&max_payload_size);
+	if (ret != EFI_SUCCESS)
+		return -EIO;
+
+	max_buffer_size = MM_COMMUNICATE_HEADER_SIZE +
+			  MM_VARIABLE_COMMUNICATE_SIZE +
+			  max_payload_size;
+
+	tee_efivar_ops.get_variable		= tee_get_variable;
+	tee_efivar_ops.get_next_variable	= tee_get_next_variable;
+	tee_efivar_ops.set_variable		= tee_set_variable;
+	tee_efivar_ops.set_variable_nonblocking	= tee_set_variable_nonblocking;
+	tee_efivar_ops.query_variable_store	= efi_query_variable_store;
+	tee_efivar_ops.query_variable_info	= tee_query_variable_info;
+
+	efivars_generic_ops_unregister();
+	pr_info("Using TEE-based EFI runtime variable services\n");
+	efivars_register(&tee_efivars, &tee_efivar_ops);
+
+	return 0;
+}
+
+static int tee_stmm_efi_remove(struct device *dev)
+{
+	tee_stmm_restore_efivars_generic_ops();
+
+	return 0;
+}
+
+MODULE_DEVICE_TABLE(tee, tee_stmm_efi_id_table);
+
+static struct tee_client_driver tee_stmm_efi_driver = {
+	.id_table	= tee_stmm_efi_id_table,
+	.driver		= {
+		.name		= "tee-stmm-efi",
+		.bus		= &tee_bus_type,
+		.probe		= tee_stmm_efi_probe,
+		.remove		= tee_stmm_efi_remove,
+	},
+};
+
+static int __init tee_stmm_efi_mod_init(void)
+{
+	return driver_register(&tee_stmm_efi_driver.driver);
+}
+
+static void __exit tee_stmm_efi_mod_exit(void)
+{
+	driver_unregister(&tee_stmm_efi_driver.driver);
+}
+
+module_init(tee_stmm_efi_mod_init);
+module_exit(tee_stmm_efi_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ilias Apalodimas <ilias.apalodimas@linaro.org>");
+MODULE_AUTHOR("Masahisa Kojima <masahisa.kojima@linaro.org>");
+MODULE_DESCRIPTION("TEE based EFI runtime variable service driver");