// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Copyright (c) 2015-2016, Linaro Limited

   */
  #include <linux/device.h>
  #include <linux/dma-buf.h>
  #include <linux/fdtable.h>
  #include <linux/idr.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/tee_drv.h>

  #include <linux/uio.h>

  #include "tee_private.h"

  static void release_registered_pages(struct tee_shm *shm)
  {
  	if (shm->pages) {
  		if (shm->flags & TEE_SHM_USER_MAPPED) {
  			unpin_user_pages(shm->pages, shm->num_pages);
  		} else {
  			size_t n;
  
  			for (n = 0; n < shm->num_pages; n++)
  				put_page(shm->pages[n]);
  		}
  
  		kfree(shm->pages);
  	}
  }

  static void tee_shm_release(struct tee_shm *shm)
  {

  	struct tee_device *teedev = shm->ctx->teedev;

  	if (shm->flags & TEE_SHM_DMA_BUF) {
  		mutex_lock(&teedev->mutex);
  		idr_remove(&teedev->idr, shm->id);
  		mutex_unlock(&teedev->mutex);
  	}

  	if (shm->flags & TEE_SHM_POOL) {
  		struct tee_shm_pool_mgr *poolm;
  
  		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) {

  		int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
  
  		if (rc)
  			dev_err(teedev->dev.parent,
  				"unregister shm %p failed: %d", shm, rc);

  		release_registered_pages(shm);

  	}

  	teedev_ctx_put(shm->ctx);

  	kfree(shm);
  
  	tee_device_put(teedev);
  }
  
  static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
  			*attach, enum dma_data_direction dir)
  {
  	return NULL;
  }
  
  static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
  				     struct sg_table *table,
  				     enum dma_data_direction dir)
  {
  }
  
  static void tee_shm_op_release(struct dma_buf *dmabuf)
  {
  	struct tee_shm *shm = dmabuf->priv;
  
  	tee_shm_release(shm);
  }

  static int tee_shm_op_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
  {
  	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_USER_MAPPED)

  		return -EINVAL;

  	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
  			       size, vma->vm_page_prot);
  }

  static const struct dma_buf_ops tee_shm_dma_buf_ops = {

  	.map_dma_buf = tee_shm_op_map_dma_buf,
  	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
  	.release = tee_shm_op_release,

  	.mmap = tee_shm_op_mmap,
  };

  struct tee_shm *tee_shm_alloc(struct tee_context *ctx, 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 (!(flags & TEE_SHM_MAPPED)) {
  		dev_err(teedev->dev.parent,
  			"only mapped allocations supported
  ");
  		return ERR_PTR(-EINVAL);
  	}
  
  	if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) {
  		dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
  		return ERR_PTR(-EINVAL);
  	}
  
  	if (!tee_device_get(teedev))
  		return ERR_PTR(-EINVAL);
  
  	if (!teedev->pool) {
  		/* teedev has been detached from driver */
  		ret = ERR_PTR(-EINVAL);
  		goto err_dev_put;
  	}
  
  	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
  	if (!shm) {
  		ret = ERR_PTR(-ENOMEM);
  		goto err_dev_put;
  	}

  	shm->flags = flags | TEE_SHM_POOL;

  	shm->ctx = ctx;
  	if (flags & TEE_SHM_DMA_BUF)

  		poolm = teedev->pool->dma_buf_mgr;

  	else

  		poolm = teedev->pool->private_mgr;

  
  	rc = poolm->ops->alloc(poolm, shm, size);
  	if (rc) {
  		ret = ERR_PTR(rc);
  		goto err_kfree;
  	}

  
  	if (flags & TEE_SHM_DMA_BUF) {
  		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

  		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_pool_free;
  		}

  		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);
  			goto err_rem;
  		}
  	}

  	teedev_ctx_get(ctx);

  
  	return shm;
  err_rem:

  	if (flags & TEE_SHM_DMA_BUF) {
  		mutex_lock(&teedev->mutex);
  		idr_remove(&teedev->idr, shm->id);
  		mutex_unlock(&teedev->mutex);
  	}

  err_pool_free:
  	poolm->ops->free(poolm, shm);
  err_kfree:
  	kfree(shm);
  err_dev_put:
  	tee_device_put(teedev);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(tee_shm_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_user_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
  	const u32 req_kernel_flags = TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED;

  	struct tee_shm *shm;
  	void *ret;
  	int rc;
  	int num_pages;
  	unsigned long start;

  	if (flags != req_user_flags && flags != req_kernel_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);
  	}

  	teedev_ctx_get(ctx);

  	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
  	if (!shm) {
  		ret = ERR_PTR(-ENOMEM);
  		goto err;
  	}
  
  	shm->flags = flags | TEE_SHM_REGISTER;

  	shm->ctx = ctx;
  	shm->id = -1;

  	addr = untagged_addr(addr);

  	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;
  	}

  	if (flags & TEE_SHM_USER_MAPPED) {

  		rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,

  					 shm->pages);
  	} else {
  		struct kvec *kiov;
  		int i;
  
  		kiov = kcalloc(num_pages, sizeof(*kiov), GFP_KERNEL);
  		if (!kiov) {
  			ret = ERR_PTR(-ENOMEM);
  			goto err;
  		}
  
  		for (i = 0; i < num_pages; i++) {
  			kiov[i].iov_base = (void *)(start + i * PAGE_SIZE);
  			kiov[i].iov_len = PAGE_SIZE;
  		}
  
  		rc = get_kernel_pages(kiov, num_pages, 0, shm->pages);
  		kfree(kiov);
  	}

  	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, start);

  	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;
  		}
  	}

  	return shm;
  err:
  	if (shm) {

  		if (shm->id >= 0) {
  			mutex_lock(&teedev->mutex);
  			idr_remove(&teedev->idr, shm->id);
  			mutex_unlock(&teedev->mutex);
  		}

  		release_registered_pages(shm);

  	}
  	kfree(shm);

  	teedev_ctx_put(ctx);

  	tee_device_put(teedev);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(tee_shm_register);

  /**
   * tee_shm_get_fd() - Increase reference count and return file descriptor
   * @shm:	Shared memory handle
   * @returns user space file descriptor to shared memory
   */
  int tee_shm_get_fd(struct tee_shm *shm)
  {

  	int fd;

  	if (!(shm->flags & TEE_SHM_DMA_BUF))

  		return -EINVAL;

  	get_dma_buf(shm->dmabuf);

  	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);

  	if (fd < 0)
  		dma_buf_put(shm->dmabuf);

  	return fd;
  }
  
  /**
   * tee_shm_free() - Free shared memory
   * @shm:	Handle to shared memory to free
   */
  void tee_shm_free(struct tee_shm *shm)
  {
  	/*
  	 * dma_buf_put() decreases the dmabuf reference counter and will
  	 * call tee_shm_release() when the last reference is gone.
  	 *
  	 * In the case of driver private memory we call tee_shm_release
  	 * directly instead as it doesn't have a reference counter.
  	 */
  	if (shm->flags & TEE_SHM_DMA_BUF)
  		dma_buf_put(shm->dmabuf);
  	else
  		tee_shm_release(shm);
  }
  EXPORT_SYMBOL_GPL(tee_shm_free);
  
  /**
   * tee_shm_va2pa() - Get physical address of a virtual address
   * @shm:	Shared memory handle
   * @va:		Virtual address to tranlsate
   * @pa:		Returned physical address
   * @returns 0 on success and < 0 on failure
   */
  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;
  	if ((char *)va >= ((char *)shm->kaddr + shm->size))
  		return -EINVAL;
  
  	return tee_shm_get_pa(
  			shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
  }
  EXPORT_SYMBOL_GPL(tee_shm_va2pa);
  
  /**
   * tee_shm_pa2va() - Get virtual address of a physical address
   * @shm:	Shared memory handle
   * @pa:		Physical address to tranlsate
   * @va:		Returned virtual address
   * @returns 0 on success and < 0 on failure
   */
  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;
  	if (pa >= (shm->paddr + shm->size))
  		return -EINVAL;
  
  	if (va) {
  		void *v = tee_shm_get_va(shm, pa - shm->paddr);
  
  		if (IS_ERR(v))
  			return PTR_ERR(v);
  		*va = v;
  	}
  	return 0;
  }
  EXPORT_SYMBOL_GPL(tee_shm_pa2va);
  
  /**
   * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
   * @shm:	Shared memory handle
   * @offs:	Offset from start of this shared memory
   * @returns virtual address of the shared memory + offs if offs is within
   *	the bounds of this shared memory, else an ERR_PTR
   */
  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;
  }
  EXPORT_SYMBOL_GPL(tee_shm_get_va);
  
  /**
   * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
   * @shm:	Shared memory handle
   * @offs:	Offset from start of this shared memory
   * @pa:		Physical address to return
   * @returns 0 if offs is within the bounds of this shared memory, else an
   *	error code.
   */
  int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
  {
  	if (offs >= shm->size)
  		return -EINVAL;
  	if (pa)
  		*pa = shm->paddr + offs;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(tee_shm_get_pa);
  
  /**
   * tee_shm_get_from_id() - Find shared memory object and increase reference
   * count
   * @ctx:	Context owning the shared memory
   * @id:		Id of shared memory object
   * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
   */
  struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
  {
  	struct tee_device *teedev;
  	struct tee_shm *shm;
  
  	if (!ctx)
  		return ERR_PTR(-EINVAL);
  
  	teedev = ctx->teedev;
  	mutex_lock(&teedev->mutex);
  	shm = idr_find(&teedev->idr, id);
  	if (!shm || shm->ctx != ctx)
  		shm = ERR_PTR(-EINVAL);
  	else if (shm->flags & TEE_SHM_DMA_BUF)
  		get_dma_buf(shm->dmabuf);
  	mutex_unlock(&teedev->mutex);
  	return shm;
  }
  EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
  
  /**

   * tee_shm_put() - Decrease reference count on a shared memory handle
   * @shm:	Shared memory handle
   */
  void tee_shm_put(struct tee_shm *shm)
  {
  	if (shm->flags & TEE_SHM_DMA_BUF)
  		dma_buf_put(shm->dmabuf);
  }
  EXPORT_SYMBOL_GPL(tee_shm_put);