linux/drivers/tee/optee/core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015-2021, Linaro Limited
 * Copyright (c) 2016, EPAM Systems
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/crash_dump.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/rpmb.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tee_core.h>
#include <linux/types.h>
#include "optee_private.h"

struct blocking_notifier_head optee_rpmb_intf_added =
	BLOCKING_NOTIFIER_INIT(optee_rpmb_intf_added);

static int rpmb_add_dev(struct device *dev)
{
	blocking_notifier_call_chain(&optee_rpmb_intf_added, 0,
				     to_rpmb_dev(dev));

	return 0;
}

static struct class_interface rpmb_class_intf = {
	.add_dev = rpmb_add_dev,
};

void optee_bus_scan_rpmb(struct work_struct *work)
{
	struct optee *optee = container_of(work, struct optee,
					   rpmb_scan_bus_work);
	int ret;

	if (!optee->rpmb_scan_bus_done) {
		ret = optee_enumerate_devices(PTA_CMD_GET_DEVICES_RPMB);
		optee->rpmb_scan_bus_done = !ret;
		if (ret && ret != -ENODEV)
			pr_info("Scanning for RPMB device: ret %d\n", ret);
	}
}

int optee_rpmb_intf_rdev(struct notifier_block *intf, unsigned long action,
			 void *data)
{
	struct optee *optee = container_of(intf, struct optee, rpmb_intf);

	schedule_work(&optee->rpmb_scan_bus_work);

	return 0;
}

static void optee_bus_scan(struct work_struct *work)
{
	WARN_ON(optee_enumerate_devices(PTA_CMD_GET_DEVICES_SUPP));
}

static ssize_t rpmb_routing_model_show(struct device *dev,
				       struct device_attribute *attr, char *buf)
{
	struct optee *optee = dev_get_drvdata(dev);
	const char *s;

	if (optee->in_kernel_rpmb_routing)
		s = "kernel";
	else
		s = "user";

	return scnprintf(buf, PAGE_SIZE, "%s\n", s);
}
static DEVICE_ATTR_RO(rpmb_routing_model);

static struct attribute *optee_dev_attrs[] = {
	&dev_attr_rpmb_routing_model.attr,
	NULL
};

ATTRIBUTE_GROUPS(optee_dev);

void optee_set_dev_group(struct optee *optee)
{
	tee_device_set_dev_groups(optee->teedev, optee_dev_groups);
	tee_device_set_dev_groups(optee->supp_teedev, optee_dev_groups);
}

int optee_open(struct tee_context *ctx, bool cap_memref_null)
{
	struct optee_context_data *ctxdata;
	struct tee_device *teedev = ctx->teedev;
	struct optee *optee = tee_get_drvdata(teedev);

	ctxdata = kzalloc(sizeof(*ctxdata), GFP_KERNEL);
	if (!ctxdata)
		return -ENOMEM;

	if (teedev == optee->supp_teedev) {
		bool busy = true;

		mutex_lock(&optee->supp.mutex);
		if (!optee->supp.ctx) {
			busy = false;
			optee->supp.ctx = ctx;
		}
		mutex_unlock(&optee->supp.mutex);
		if (busy) {
			kfree(ctxdata);
			return -EBUSY;
		}

		if (!optee->scan_bus_done) {
			INIT_WORK(&optee->scan_bus_work, optee_bus_scan);
			schedule_work(&optee->scan_bus_work);
			optee->scan_bus_done = true;
		}
	}
	mutex_init(&ctxdata->mutex);
	INIT_LIST_HEAD(&ctxdata->sess_list);

	ctx->cap_memref_null = cap_memref_null;
	ctx->data = ctxdata;
	return 0;
}

static void optee_release_helper(struct tee_context *ctx,
				 int (*close_session)(struct tee_context *ctx,
						      u32 session,
						      bool system_thread))
{
	struct optee_context_data *ctxdata = ctx->data;
	struct optee_session *sess;
	struct optee_session *sess_tmp;

	if (!ctxdata)
		return;

	list_for_each_entry_safe(sess, sess_tmp, &ctxdata->sess_list,
				 list_node) {
		list_del(&sess->list_node);
		close_session(ctx, sess->session_id, sess->use_sys_thread);
		kfree(sess);
	}
	kfree(ctxdata);
	ctx->data = NULL;
}

void optee_release(struct tee_context *ctx)
{
	optee_release_helper(ctx, optee_close_session_helper);
}

void optee_release_supp(struct tee_context *ctx)
{
	struct optee *optee = tee_get_drvdata(ctx->teedev);

	optee_release_helper(ctx, optee_close_session_helper);

	optee_supp_release(&optee->supp);
}

void optee_remove_common(struct optee *optee)
{
	blocking_notifier_chain_unregister(&optee_rpmb_intf_added,
					   &optee->rpmb_intf);
	cancel_work_sync(&optee->rpmb_scan_bus_work);
	/* Unregister OP-TEE specific client devices on TEE bus */
	optee_unregister_devices();

	optee_notif_uninit(optee);
	optee_shm_arg_cache_uninit(optee);
	teedev_close_context(optee->ctx);
	/*
	 * The two devices have to be unregistered before we can free the
	 * other resources.
	 */
	tee_device_unregister(optee->supp_teedev);
	tee_device_unregister(optee->teedev);

	tee_shm_pool_free(optee->pool);
	optee_supp_uninit(&optee->supp);
	mutex_destroy(&optee->call_queue.mutex);
	rpmb_dev_put(optee->rpmb_dev);
	mutex_destroy(&optee->rpmb_dev_mutex);
}

static int smc_abi_rc;
static int ffa_abi_rc;
static bool intf_is_regged;

static int __init optee_core_init(void)
{
	int rc;

	/*
	 * The kernel may have crashed at the same time that all available
	 * secure world threads were suspended and we cannot reschedule the
	 * suspended threads without access to the crashed kernel's wait_queue.
	 * Therefore, we cannot reliably initialize the OP-TEE driver in the
	 * kdump kernel.
	 */
	if (is_kdump_kernel())
		return -ENODEV;

	if (IS_REACHABLE(CONFIG_RPMB)) {
		rc = rpmb_interface_register(&rpmb_class_intf);
		if (rc)
			return rc;
		intf_is_regged = true;
	}

	smc_abi_rc = optee_smc_abi_register();
	ffa_abi_rc = optee_ffa_abi_register();

	/* If both failed there's no point with this module */
	if (smc_abi_rc && ffa_abi_rc) {
		if (IS_REACHABLE(CONFIG_RPMB)) {
			rpmb_interface_unregister(&rpmb_class_intf);
			intf_is_regged = false;
		}
		return smc_abi_rc;
	}

	return 0;
}
module_init(optee_core_init);

static void __exit optee_core_exit(void)
{
	if (IS_REACHABLE(CONFIG_RPMB) && intf_is_regged) {
		rpmb_interface_unregister(&rpmb_class_intf);
		intf_is_regged = false;
	}

	if (!smc_abi_rc)
		optee_smc_abi_unregister();
	if (!ffa_abi_rc)
		optee_ffa_abi_unregister();
}
module_exit(optee_core_exit);

MODULE_AUTHOR("Linaro");
MODULE_DESCRIPTION("OP-TEE driver");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:optee");