drivers/misc/mediatek/mtee/tz_mem.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2021 MediaTek Inc.
 */

/* Release secure chunk memory for normal world usage.
 *
 * For better utilization, part of secure chunk memory (pre-defined size) can
 * be used by normal world through memory TA.
 * After release, pre-defined secure memory can be read/write by normal world
 * through memroy TA, and can not be used by secure world. After append, it
 * can be used for secure world again.
 * For easy usage at user level, a block device can be registered, and it can
 * access released secure chunk memory by memory TA.
 *
 * How to use secure chunk memory at user level:
 * 1) Create a block device node, ex: /dev/tzmem
 * 2) Release secure chunk memory by UREE_ReleaseSecurechunkmem.
 *    After releasing, the pre-defined chunk memory will be used by normal
 *    world only.
 * 3) Open /dev/tzmem for read/write
 * 4) If finishing to use, close it.
 * 5) Append secure chunk memory back to secure world usage by
 *    UREE_AppendSecurechunkmem.
 *    After appending, the pre-defined chunk memory will not be used by normal
 *    world.
 *
 * Or simply, using APIs
 * 1) UREE_ReleaseTzmem for release secure chunk memory to normal world usage.
 * 2) UREE_AppendTzmem for append secure chunk memory back to secure world.
 *
 */

/* ------------------------------------------------------------------------- */
/* Include files */
/* ------------------------------------------------------------------------- */

#include <trustzone/kree/mem.h>
#include "trustzone/kree/system.h"
#include <tz_cross/ta_mem.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include "trustzone/kree/tz_mem.h"

/* Use this define to enable module for TZMEM
 */
/* #define MTEE_TZMEM_ENABLE */

/* enable debug logs
 */
#define MTEE_TZMEM_DBG

#define KREE_RELEASECM_MAX_SIZE 4096	/* bytes */


struct tzmem_diskinfo_s {
	uint32_t control;	/* 0 = not released, 1 = released */
	uint32_t size;		/* real released pool size in bytes */
	uint32_t pool_size;
	struct gendisk *disk;
	KREE_SESSION_HANDLE session;
	KREE_RELEASECM_HANDLE handle;
};

#ifdef MTEE_TZMEM_ENABLE
static uint32_t tzmem_poolIndex; /* currently, always 0. for future extension */
static struct tzmem_diskinfo_s _tzmem_diskInfo[IO_NODE_NUMBER_TZMEM];

static DEFINE_MUTEX(tzmem_probe_mutex);
static DEFINE_SPINLOCK(tzmem_blk_lock);

static int _tzmem_get_poolsize(uint32_t *size)
{
	KREE_SESSION_HANDLE session;
	int ret = TZ_RESULT_SUCCESS;

	ret = KREE_CreateSession(TZ_TA_MEM_UUID, &session);
	if (ret != TZ_RESULT_SUCCESS) {
		pr_warn("[%s] %s: KREE_CreateSession Error = 0x%x\n",
			MODULE_NAME, __func__, ret);
		return ret;
	}
	/* get ta preset tzmem size */
	ret = KREE_GetSecurechunkReleaseSize(session, size);
	if (ret != TZ_RESULT_SUCCESS) {
		pr_warn("[%s] %s: Error = 0x%x\n",
			MODULE_NAME, __func__, ret);
		KREE_CloseSession(session);
		return ret;
	}

	ret = KREE_CloseSession(session);
	if (ret != TZ_RESULT_SUCCESS) {
		pr_warn("[%s] %s: KREE_CloseSession Error = 0x%x\n",
			    MODULE_NAME, __func__, ret);
		return ret;
	}

	return ret;
}

static long tzmem_gen_ioctl(dev_t dev, unsigned int cmd, unsigned long arg)
{
	int ret = 0;

#ifdef MTEE_TZMEM_DBG
	pr_debug("====> %s\n", __func__);
#endif

	switch (cmd) {
	default:
		ret = -EINVAL;
	}

	return ret;
}

static void do_tzmem_blk_request(struct request_queue *q)
{
	struct request *req;
	uint32_t i;

#ifdef MTEE_TZMEM_DBG
	pr_debug("====> %s\n", __func__);
#endif

	req = blk_fetch_request(q);
	while (req) {
		unsigned long start = blk_rq_pos(req) << 9;
		unsigned long len = blk_rq_cur_bytes(req);
		int err = 0;
		struct gendisk *disk = req->rq_disk;
		struct tzmem_diskinfo_s *diskInfo =
				(struct tzmem_diskinfo_s *) disk->private_data;
		KREE_SESSION_HANDLE session;

		session = diskInfo->session;

#ifdef MTEE_TZMEM_DBG
		pr_debug("====> 0x%x 0x%x\n", session, diskInfo->size);
#endif

		if ((start + len > diskInfo->size) || (start > diskInfo->size)
		    || (len > diskInfo->size)) {
			err = -EIO;
			goto done;
		}

		if (rq_data_dir(req) == READ) {
#ifdef MTEE_TZMEM_DBG
			pr_debug("====> %s: read = 0x%x, 0x%x\n", __func__,
				(uint32_t) start,
				(uint32_t) len);
#endif
			for (i = 0; i < len / KREE_RELEASECM_MAX_SIZE; i++) {
				KREE_ReadSecurechunkmem(
				(KREE_SESSION_HANDLE) session,
				start + i * KREE_RELEASECM_MAX_SIZE,
				KREE_RELEASECM_MAX_SIZE,
				req->buffer + i * KREE_RELEASECM_MAX_SIZE);
			}
			if (len % KREE_RELEASECM_MAX_SIZE) {
				KREE_ReadSecurechunkmem(
				(KREE_SESSION_HANDLE) session,
				start + i * KREE_RELEASECM_MAX_SIZE,
				len % KREE_RELEASECM_MAX_SIZE,
				req->buffer + i * KREE_RELEASECM_MAX_SIZE);
			}
		} else {
#ifdef MTEE_TZMEM_DBG
			pr_debug("====> %s: write = 0x%x, 0x%x\n", __func__
				(uint32_t) start, (uint32_t) len);
#endif
			for (i = 0; i < len / KREE_RELEASECM_MAX_SIZE; i++) {
				KREE_WriteSecurechunkmem(
				(KREE_SESSION_HANDLE) session,
				start + i * KREE_RELEASECM_MAX_SIZE,
				KREE_RELEASECM_MAX_SIZE,
				req->buffer + i * KREE_RELEASECM_MAX_SIZE);
			}
			if (len % KREE_RELEASECM_MAX_SIZE) {
				KREE_WriteSecurechunkmem(
				(KREE_SESSION_HANDLE) session,
				 start + i * KREE_RELEASECM_MAX_SIZE,
				 len % KREE_RELEASECM_MAX_SIZE,
				 req->buffer + i * KREE_RELEASECM_MAX_SIZE);
			}

		}

 done:
		if (!__blk_end_request_cur(req, err))
			req = blk_fetch_request(q);
	}
}

static int tzmem_blk_ioctl(struct block_device *bdev, fmode_t mode,
				unsigned int cmd, unsigned long arg)
{
	return tzmem_gen_ioctl(bdev->bd_dev, cmd, arg);
}

/* block device module info */
static const struct block_device_operations tzmem_blk_fops = {
	.owner = THIS_MODULE,
	.ioctl = tzmem_blk_ioctl,
};

/* block device probe function */
/* Create disk on demand. So we won't create lots of disk for un-used
 * devices.
 */
static struct kobject *tzmem_blk_probe(dev_t dev, int *part, void *data)
{
	uint32_t len;
	struct gendisk *disk;
	struct kobject *kobj;
	struct request_queue *queue;
	struct tzmem_diskinfo_s *diskInfo;
	int ret;
	KREE_SESSION_HANDLE session;

#ifdef MTEE_TZMEM_DBG
	pr_debug("====> %s\n", __func__);
#endif

	mutex_lock(&tzmem_probe_mutex);

	diskInfo = (struct tzmem_diskinfo_s *)
			&_tzmem_diskInfo[tzmem_poolIndex];
	if (diskInfo->disk == NULL) {
		disk = alloc_disk(1);
		if (!disk)
			goto out_info;

		queue = blk_init_queue(do_tzmem_blk_request, &tzmem_blk_lock);
		if (!queue)
			goto out_queue;

		blk_queue_max_hw_sectors(queue, 1024);
		blk_queue_bounce_limit(queue, BLK_BOUNCE_ANY);

		if (_tzmem_get_poolsize(&len))
			goto out_init;

		disk->major = IO_NODE_MAJOR_TZMEM;
		disk->first_minor = MINOR(dev);
		disk->fops = &tzmem_blk_fops;
		disk->private_data = &_tzmem_diskInfo;
		snprintf(disk->disk_name, sizeof(disk->disk_name), "tzmem%d",
								MINOR(dev));
		disk->queue = queue;
		set_capacity(disk, len / 512);
		add_disk(disk);

		ret = KREE_CreateSession(TZ_TA_MEM_UUID, &session);
		if (ret != TZ_RESULT_SUCCESS) {
			pr_warn("[%s] _tzmem_get_poolsize: KREE_CreateSession Error = 0x%x\n",
				MODULE_NAME, ret);
			goto out_init;
		}

		diskInfo->session = session;
		diskInfo->pool_size = len;
		diskInfo->disk = disk;
		diskInfo->size = len;
	}

	*part = 0;
	kobj = diskInfo ? get_disk(diskInfo->disk) : ERR_PTR(-ENOMEM);

	mutex_unlock(&tzmem_probe_mutex);
	return kobj;

 out_init:
	blk_cleanup_queue(queue);
 out_queue:
	put_disk(disk);
 out_info:
	mutex_unlock(&tzmem_probe_mutex);
	return ERR_PTR(-ENOMEM);
}

/* tzmem block device module init
 */
static int __init tzmem_blkdev_init(void)
{
#ifdef MTEE_TZMEM_DBG
	pr_debug("====> %s\n", __func__);
#endif

	if (register_blkdev(IO_NODE_MAJOR_TZMEM, DEV_TZMEM)) {
		pr_warn("[%s] %s: register_blkdev error\n",
			MODULE_NAME, __func__);
		return -EFAULT;
	}

	blk_register_region(MKDEV(IO_NODE_MAJOR_TZMEM, IO_NODE_MINOR_TZMEM),
				IO_NODE_NUMBER_TZMEM, THIS_MODULE,
				tzmem_blk_probe, NULL, NULL);

	return 0;
}
module_init(tzmem_blkdev_init);
#endif