tee: add register user memory

Added new ioctl to allow users register own buffers as a shared memory.

Signed-off-by: Volodymyr Babchuk <[e-mail]>
[jw: moved tee_shm_is_registered() declaration]
[jw: added space after __tee_shm_alloc() implementation]
Signed-off-by: Jens Wiklander <[e-mail]>

drivers/tee/tee_core.c

···
 	if (data.flags)
 		return -EINVAL;
 
-	data.id = -1;
-
 	shm = tee_shm_alloc(ctx, data.size, TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
 	if (IS_ERR(shm))
 		return PTR_ERR(shm);
···
 	else
 		ret = tee_shm_get_fd(shm);
 
+	/*
+	 * When user space closes the file descriptor the shared memory
+	 * should be freed or if tee_shm_get_fd() failed then it will
+	 * be freed immediately.
+	 */
+	tee_shm_put(shm);
+	return ret;
+}
+
+static int
+tee_ioctl_shm_register(struct tee_context *ctx,
+		       struct tee_ioctl_shm_register_data __user *udata)
+{
+	long ret;
+	struct tee_ioctl_shm_register_data data;
+	struct tee_shm *shm;
+
+	if (copy_from_user(&data, udata, sizeof(data)))
+		return -EFAULT;
+
+	/* Currently no input flags are supported */
+	if (data.flags)
+		return -EINVAL;
+
+	shm = tee_shm_register(ctx, data.addr, data.length,
+			       TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
+	if (IS_ERR(shm))
+		return PTR_ERR(shm);
+
+	data.id = shm->id;
+	data.flags = shm->flags;
+	data.length = shm->size;
+
+	if (copy_to_user(udata, &data, sizeof(data)))
+		ret = -EFAULT;
+	else
+		ret = tee_shm_get_fd(shm);
 	/*
 	 * When user space closes the file descriptor the shared memory
 	 * should be freed or if tee_shm_get_fd() failed then it will
···
 		return tee_ioctl_version(ctx, uarg);
 	case TEE_IOC_SHM_ALLOC:
 		return tee_ioctl_shm_alloc(ctx, uarg);
+	case TEE_IOC_SHM_REGISTER:
+		return tee_ioctl_shm_register(ctx, uarg);
 	case TEE_IOC_OPEN_SESSION:
 		return tee_ioctl_open_session(ctx, uarg);
 	case TEE_IOC_INVOKE:

drivers/tee/tee_shm.c

···
 static void tee_shm_release(struct tee_shm *shm)
 {
 	struct tee_device *teedev = shm->teedev;
-	struct tee_shm_pool_mgr *poolm;
 
 	mutex_lock(&teedev->mutex);
 	idr_remove(&teedev->idr, shm->id);
···
 		list_del(&shm->link);
 	mutex_unlock(&teedev->mutex);
 
-	if (shm->flags & TEE_SHM_DMA_BUF)
-		poolm = teedev->pool->dma_buf_mgr;
-	else
-		poolm = teedev->pool->private_mgr;
+	if (shm->flags & TEE_SHM_POOL) {
+		struct tee_shm_pool_mgr *poolm;
 
-	poolm->ops->free(poolm, shm);
+		if (shm->flags & TEE_SHM_DMA_BUF)
+			poolm = teedev->pool->dma_buf_mgr;
+		else
+			poolm = teedev->pool->private_mgr;
+
+		poolm->ops->free(poolm, shm);
+	} else if (shm->flags & TEE_SHM_REGISTER) {
+		size_t n;
+		int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
+
+		if (rc)
+			dev_err(teedev->dev.parent,
+				"unregister shm %p failed: %d", shm, rc);
+
+		for (n = 0; n < shm->num_pages; n++)
+			put_page(shm->pages[n]);
+
+		kfree(shm->pages);
+	}
+
 	kfree(shm);
 
 	tee_device_put(teedev);
···
 	struct tee_shm *shm = dmabuf->priv;
 	size_t size = vma->vm_end - vma->vm_start;
 
+	/* Refuse sharing shared memory provided by application */
+	if (shm->flags & TEE_SHM_REGISTER)
+		return -EINVAL;
+
 	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
 			       size, vma->vm_page_prot);
 }
···
 	.mmap = tee_shm_op_mmap,
 };
 
-/**
- * tee_shm_alloc() - Allocate shared memory
- * @ctx:	Context that allocates the shared memory
- * @size:	Requested size of shared memory
- * @flags:	Flags setting properties for the requested shared memory.
- *
- * Memory allocated as global shared memory is automatically freed when the
- * TEE file pointer is closed. The @flags field uses the bits defined by
- * TEE_SHM_* in <linux/tee_drv.h>. TEE_SHM_MAPPED must currently always be
- * set. If TEE_SHM_DMA_BUF global shared memory will be allocated and
- * associated with a dma-buf handle, else driver private memory.
- */
-struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
+struct tee_shm *__tee_shm_alloc(struct tee_context *ctx,
+				struct tee_device *teedev,
+				size_t size, u32 flags)
 {
-	struct tee_device *teedev = ctx->teedev;
 	struct tee_shm_pool_mgr *poolm = NULL;
 	struct tee_shm *shm;
 	void *ret;
 	int rc;
+
+	if (ctx && ctx->teedev != teedev) {
+		dev_err(teedev->dev.parent, "ctx and teedev mismatch\n");
+		return ERR_PTR(-EINVAL);
+	}
 
 	if (!(flags & TEE_SHM_MAPPED)) {
 		dev_err(teedev->dev.parent,
···
 		goto err_dev_put;
 	}
 
-	shm->flags = flags;
+	shm->flags = flags | TEE_SHM_POOL;
 	shm->teedev = teedev;
 	shm->ctx = ctx;
 	if (flags & TEE_SHM_DMA_BUF)
···
 			goto err_rem;
 		}
 	}
-	mutex_lock(&teedev->mutex);
-	list_add_tail(&shm->link, &ctx->list_shm);
-	mutex_unlock(&teedev->mutex);
+
+	if (ctx) {
+		mutex_lock(&teedev->mutex);
+		list_add_tail(&shm->link, &ctx->list_shm);
+		mutex_unlock(&teedev->mutex);
+	}
 
 	return shm;
 err_rem:
···
 	tee_device_put(teedev);
 	return ret;
 }
+
+/**
+ * tee_shm_alloc() - Allocate shared memory
+ * @ctx:	Context that allocates the shared memory
+ * @size:	Requested size of shared memory
+ * @flags:	Flags setting properties for the requested shared memory.
+ *
+ * Memory allocated as global shared memory is automatically freed when the
+ * TEE file pointer is closed. The @flags field uses the bits defined by
+ * TEE_SHM_* in <linux/tee_drv.h>. TEE_SHM_MAPPED must currently always be
+ * set. If TEE_SHM_DMA_BUF global shared memory will be allocated and
+ * associated with a dma-buf handle, else driver private memory.
+ */
+struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
+{
+	return __tee_shm_alloc(ctx, ctx->teedev, size, flags);
+}
 EXPORT_SYMBOL_GPL(tee_shm_alloc);
+
+struct tee_shm *tee_shm_priv_alloc(struct tee_device *teedev, size_t size)
+{
+	return __tee_shm_alloc(NULL, teedev, size, TEE_SHM_MAPPED);
+}
+EXPORT_SYMBOL_GPL(tee_shm_priv_alloc);
+
+struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
+				 size_t length, u32 flags)
+{
+	struct tee_device *teedev = ctx->teedev;
+	const u32 req_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
+	struct tee_shm *shm;
+	void *ret;
+	int rc;
+	int num_pages;
+	unsigned long start;
+
+	if (flags != req_flags)
+		return ERR_PTR(-ENOTSUPP);
+
+	if (!tee_device_get(teedev))
+		return ERR_PTR(-EINVAL);
+
+	if (!teedev->desc->ops->shm_register ||
+	    !teedev->desc->ops->shm_unregister) {
+		tee_device_put(teedev);
+		return ERR_PTR(-ENOTSUPP);
+	}
+
+	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
+	if (!shm) {
+		ret = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+
+	shm->flags = flags | TEE_SHM_REGISTER;
+	shm->teedev = teedev;
+	shm->ctx = ctx;
+	shm->id = -1;
+	start = rounddown(addr, PAGE_SIZE);
+	shm->offset = addr - start;
+	shm->size = length;
+	num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
+	shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
+	if (!shm->pages) {
+		ret = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+
+	rc = get_user_pages_fast(start, num_pages, 1, shm->pages);
+	if (rc > 0)
+		shm->num_pages = rc;
+	if (rc != num_pages) {
+		if (rc > 0)
+			rc = -ENOMEM;
+		ret = ERR_PTR(rc);
+		goto err;
+	}
+
+	mutex_lock(&teedev->mutex);
+	shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
+	mutex_unlock(&teedev->mutex);
+
+	if (shm->id < 0) {
+		ret = ERR_PTR(shm->id);
+		goto err;
+	}
+
+	rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
+					     shm->num_pages);
+	if (rc) {
+		ret = ERR_PTR(rc);
+		goto err;
+	}
+
+	if (flags & TEE_SHM_DMA_BUF) {
+		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+		exp_info.ops = &tee_shm_dma_buf_ops;
+		exp_info.size = shm->size;
+		exp_info.flags = O_RDWR;
+		exp_info.priv = shm;
+
+		shm->dmabuf = dma_buf_export(&exp_info);
+		if (IS_ERR(shm->dmabuf)) {
+			ret = ERR_CAST(shm->dmabuf);
+			teedev->desc->ops->shm_unregister(ctx, shm);
+			goto err;
+		}
+	}
+
+	mutex_lock(&teedev->mutex);
+	list_add_tail(&shm->link, &ctx->list_shm);
+	mutex_unlock(&teedev->mutex);
+
+	return shm;
+err:
+	if (shm) {
+		size_t n;
+
+		if (shm->id >= 0) {
+			mutex_lock(&teedev->mutex);
+			idr_remove(&teedev->idr, shm->id);
+			mutex_unlock(&teedev->mutex);
+		}
+		for (n = 0; n < shm->num_pages; n++)
+			put_page(shm->pages[n]);
+		kfree(shm->pages);
+	}
+	kfree(shm);
+	tee_device_put(teedev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tee_shm_register);
 
 /**
  * tee_shm_get_fd() - Increase reference count and return file descriptor
···
  */
 int tee_shm_get_fd(struct tee_shm *shm)
 {
-	u32 req_flags = TEE_SHM_MAPPED | TEE_SHM_DMA_BUF;
 	int fd;
 
-	if ((shm->flags & req_flags) != req_flags)
+	if (!(shm->flags & TEE_SHM_DMA_BUF))
 		return -EINVAL;
 
 	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
···
  */
 int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
 {
+	if (!(shm->flags & TEE_SHM_MAPPED))
+		return -EINVAL;
 	/* Check that we're in the range of the shm */
 	if ((char *)va < (char *)shm->kaddr)
 		return -EINVAL;
···
  */
 int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
 {
+	if (!(shm->flags & TEE_SHM_MAPPED))
+		return -EINVAL;
 	/* Check that we're in the range of the shm */
 	if (pa < shm->paddr)
 		return -EINVAL;
···
  */
 void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
 {
+	if (!(shm->flags & TEE_SHM_MAPPED))
+		return ERR_PTR(-EINVAL);
 	if (offs >= shm->size)
 		return ERR_PTR(-EINVAL);
 	return (char *)shm->kaddr + offs;

include/linux/tee_drv.h

···
  * specific TEE driver.
  */
 
-#define TEE_SHM_MAPPED		0x1	/* Memory mapped by the kernel */
-#define TEE_SHM_DMA_BUF		0x2	/* Memory with dma-buf handle */
+#define TEE_SHM_MAPPED		BIT(0)	/* Memory mapped by the kernel */
+#define TEE_SHM_DMA_BUF		BIT(1)	/* Memory with dma-buf handle */
+#define TEE_SHM_EXT_DMA_BUF	BIT(2)	/* Memory with dma-buf handle */
+#define TEE_SHM_REGISTER	BIT(3)  /* Memory registered in secure world */
+#define TEE_SHM_USER_MAPPED	BIT(4)  /* Memory mapped in user space */
+#define TEE_SHM_POOL		BIT(5)  /* Memory allocated from pool */
 
 struct device;
 struct tee_device;
···
  * @cancel_req:		request cancel of an ongoing invoke or open
  * @supp_revc:		called for supplicant to get a command
  * @supp_send:		called for supplicant to send a response
+ * @shm_register:	register shared memory buffer in TEE
+ * @shm_unregister:	unregister shared memory buffer in TEE
  */
 struct tee_driver_ops {
 	void (*get_version)(struct tee_device *teedev,
···
 			 struct tee_param *param);
 	int (*supp_send)(struct tee_context *ctx, u32 ret, u32 num_params,
 			 struct tee_param *param);
+	int (*shm_register)(struct tee_context *ctx, struct tee_shm *shm,
+			    struct page **pages, size_t num_pages);
+	int (*shm_unregister)(struct tee_context *ctx, struct tee_shm *shm);
 };
 
 /**
···
  * @returns a pointer to 'struct tee_shm'
  */
 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags);
+
+/**
+ * tee_shm_priv_alloc() - Allocate shared memory privately
+ * @dev:	Device that allocates the shared memory
+ * @size:	Requested size of shared memory
+ *
+ * Allocates shared memory buffer that is not associated with any client
+ * context. Such buffers are owned by TEE driver and used for internal calls.
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_priv_alloc(struct tee_device *teedev, size_t size);
+
+/**
+ * tee_shm_register() - Register shared memory buffer
+ * @ctx:	Context that registers the shared memory
+ * @addr:	Address is userspace of the shared buffer
+ * @length:	Length of the shared buffer
+ * @flags:	Flags setting properties for the requested shared memory.
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
+				 size_t length, u32 flags);
+
+/**
+ * tee_shm_is_registered() - Check if shared memory object in registered in TEE
+ * @shm:	Shared memory handle
+ * @returns true if object is registered in TEE
+ */
+static inline bool tee_shm_is_registered(struct tee_shm *shm)
+{
+	return shm && (shm->flags & TEE_SHM_REGISTER);
+}
 
 /**
  * tee_shm_free() - Free shared memory

include/uapi/linux/tee.h

···
 
 #define TEE_GEN_CAP_GP		(1 << 0)/* GlobalPlatform compliant TEE */
 #define TEE_GEN_CAP_PRIVILEGED	(1 << 1)/* Privileged device (for supplicant) */
+#define TEE_GEN_CAP_REG_MEM	(1 << 2)/* Supports registering shared memory */
 
 /*
  * TEE Implementation ID
···
 #define TEE_IOC_SUPPL_SEND	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 7, \
 				     struct tee_ioctl_buf_data)
 
+/**
+ * struct tee_ioctl_shm_register_data - Shared memory register argument
+ * @addr:      [in] Start address of shared memory to register
+ * @length:    [in/out] Length of shared memory to register
+ * @flags:     [in/out] Flags to/from registration.
+ * @id:                [out] Identifier of the shared memory
+ *
+ * The flags field should currently be zero as input. Updated by the call
+ * with actual flags as defined by TEE_IOCTL_SHM_* above.
+ * This structure is used as argument for TEE_IOC_SHM_REGISTER below.
+ */
+struct tee_ioctl_shm_register_data {
+	__u64 addr;
+	__u64 length;
+	__u32 flags;
+	__s32 id;
+};
+
+/**
+ * TEE_IOC_SHM_REGISTER - Register shared memory argument
+ *
+ * Registers shared memory between the user space process and secure OS.
+ *
+ * Returns a file descriptor on success or < 0 on failure
+ *
+ * The shared memory is unregisterred when the descriptor is closed.
+ */
+#define TEE_IOC_SHM_REGISTER   _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 9, \
+				     struct tee_ioctl_shm_register_data)
 /*
  * Five syscalls are used when communicating with the TEE driver.
  * open(): opens the device associated with the driver