drivers/tee/tee_shm.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2015-2017, 2019-2021 Linaro Limited
  */
 #include <linux/anon_inodes.h>
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/mm.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/tee_drv.h>
 #include "tee_private.h"

 static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
 {
 	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) {
 		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);
 	}

 	if (shm->ctx)
 		teedev_ctx_put(shm->ctx);

 	kfree(shm);

 	tee_device_put(teedev);
 }

 static struct tee_shm *__tee_shm_alloc(struct tee_context *ctx,
 				       struct tee_device *teedev,
 				       size_t size, u32 flags)
 {
 	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,
 			"only mapped allocations supported\n");
 		return ERR_PTR(-EINVAL);
 	}

 	if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_PRIV))) {
 		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;
 	}

 	refcount_set(&shm->refcount, 1);
 	shm->flags = flags | TEE_SHM_POOL;
 	shm->teedev = teedev;
 	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;
 	}

 	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;
 	}

 	if (ctx) {
 		teedev_ctx_get(ctx);
 		mutex_lock(&teedev->mutex);
 		list_add_tail(&shm->link, &ctx->list_shm);
 		mutex_unlock(&teedev->mutex);
 	}

 	return shm;
 err_pool_free:
 	poolm->ops->free(poolm, shm);
 err_kfree:
 	kfree(shm);
 err_dev_put:
 	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);

 /**
  * tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer
  * @ctx:	Context that allocates the shared memory
  * @size:	Requested size of shared memory
  *
  * The returned memory registered in secure world and is suitable to be
  * passed as a memory buffer in parameter argument to
  * tee_client_invoke_func(). The memory allocated is later freed with a
  * call to tee_shm_free().
  *
  * @returns a pointer to 'struct tee_shm'
  */
 struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
 {
 	return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED);
 }
 EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);

 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);
 	}

 	teedev_ctx_get(ctx);

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

 	refcount_set(&shm->refcount, 1);
 	shm->flags = flags | TEE_SHM_REGISTER;
 	shm->teedev = teedev;
 	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;
 	}

 	rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, 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, start);
 	if (rc) {
 		ret = ERR_PTR(rc);
 		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);
 		}
 		if (shm->pages) {
 			for (n = 0; n < shm->num_pages; n++)
 				put_page(shm->pages[n]);
 			kfree(shm->pages);
 		}
 	}
 	kfree(shm);
 	teedev_ctx_put(ctx);
 	tee_device_put(teedev);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(tee_shm_register);

 static int tee_shm_fop_release(struct inode *inode, struct file *filp)
 {
 	tee_shm_put(filp->private_data);
 	return 0;
 }

 static int tee_shm_fop_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct tee_shm *shm = filp->private_data;
 	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;

 	/* check for overflowing the buffer's size */
 	if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT)
 		return -EINVAL;

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

 static const struct file_operations tee_shm_fops = {
 	.owner = THIS_MODULE,
 	.release = tee_shm_fop_release,
 	.mmap = tee_shm_fop_mmap,
 };

 /**
  * 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;

 	/* matched by tee_shm_put() in tee_shm_op_release() */
 	refcount_inc(&shm->refcount);
 	fd = anon_inode_getfd("tee_shm", &tee_shm_fops, shm, O_RDWR);
 	if (fd < 0)
 		tee_shm_put(shm);
 	return fd;
 }

 /**
  * tee_shm_free() - Free shared memory
  * @shm:	Handle to shared memory to free
  */
 void tee_shm_free(struct tee_shm *shm)
 {
 	tee_shm_put(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 the tee_shm was found in the IDR it must have a refcount
 	 * larger than 0 due to the guarantee in tee_shm_put() below. So
 	 * it's safe to use refcount_inc().
 	 */
 	if (!shm || shm->ctx != ctx)
 		shm = ERR_PTR(-EINVAL);
 	else
 		refcount_inc(&shm->refcount);
 	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)
 {
 	struct tee_device *teedev = shm->teedev;
 	bool do_release = false;

 	mutex_lock(&teedev->mutex);
 	if (refcount_dec_and_test(&shm->refcount)) {
 		/*
 		 * refcount has reached 0, we must now remove it from the
 		 * IDR before releasing the mutex. This will guarantee that
 		 * the refcount_inc() in tee_shm_get_from_id() never starts
 		 * from 0.
 		 */
 		idr_remove(&teedev->idr, shm->id);
 		if (shm->ctx)
 			list_del(&shm->link);
 		do_release = true;
 	}
 	mutex_unlock(&teedev->mutex);

 	if (do_release)
 		tee_shm_release(teedev, shm);
 }
 EXPORT_SYMBOL_GPL(tee_shm_put);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2015-2017, 2019-2021 Linaro Limited
	*/
	#include <linux/anon_inodes.h>
	#include <linux/device.h>
	#include <linux/idr.h>
	#include <linux/mm.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/tee_drv.h>
	#include "tee_private.h"

	static void tee_shm_release(struct tee_device teedev, struct tee_shm shm)
	{
	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) {
	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);
	}

	if (shm->ctx)
	teedev_ctx_put(shm->ctx);

	kfree(shm);

	tee_device_put(teedev);
	}

	static struct tee_shm __tee_shm_alloc(struct tee_context ctx,
	struct tee_device *teedev,
	size_t size, u32 flags)
	{
	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,
	"only mapped allocations supported\n");
	return ERR_PTR(-EINVAL);
	}

	if ((flags & ~(TEE_SHM_MAPPED \| TEE_SHM_DMA_BUF \| TEE_SHM_PRIV))) {
	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;
	}

	refcount_set(&shm->refcount, 1);
	shm->flags = flags \| TEE_SHM_POOL;
	shm->teedev = teedev;
	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;
	}

	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;
	}

	if (ctx) {
	teedev_ctx_get(ctx);
	mutex_lock(&teedev->mutex);
	list_add_tail(&shm->link, &ctx->list_shm);
	mutex_unlock(&teedev->mutex);
	}

	return shm;
	err_pool_free:
	poolm->ops->free(poolm, shm);
	err_kfree:
	kfree(shm);
	err_dev_put:
	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);

	/**
	* tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer
	* @ctx: Context that allocates the shared memory
	* @size: Requested size of shared memory
	*
	* The returned memory registered in secure world and is suitable to be
	* passed as a memory buffer in parameter argument to
	* tee_client_invoke_func(). The memory allocated is later freed with a
	* call to tee_shm_free().
	*
	* @returns a pointer to 'struct tee_shm'
	*/
	struct tee_shm tee_shm_alloc_kernel_buf(struct tee_context ctx, size_t size)
	{
	return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED);
	}
	EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);

	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);
	}

	teedev_ctx_get(ctx);

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

	refcount_set(&shm->refcount, 1);
	shm->flags = flags \| TEE_SHM_REGISTER;
	shm->teedev = teedev;
	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;
	}

	rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, 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, start);
	if (rc) {
	ret = ERR_PTR(rc);
	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);
	}
	if (shm->pages) {
	for (n = 0; n < shm->num_pages; n++)
	put_page(shm->pages[n]);
	kfree(shm->pages);
	}
	}
	kfree(shm);
	teedev_ctx_put(ctx);
	tee_device_put(teedev);
	return ret;
	}
	EXPORT_SYMBOL_GPL(tee_shm_register);

	static int tee_shm_fop_release(struct inode inode, struct file filp)
	{
	tee_shm_put(filp->private_data);
	return 0;
	}

	static int tee_shm_fop_mmap(struct file filp, struct vm_area_struct vma)
	{
	struct tee_shm *shm = filp->private_data;
	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;

	/* check for overflowing the buffer's size */
	if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT)
	return -EINVAL;

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

	static const struct file_operations tee_shm_fops = {
	.owner = THIS_MODULE,
	.release = tee_shm_fop_release,
	.mmap = tee_shm_fop_mmap,
	};

	/**
	* 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;

	/* matched by tee_shm_put() in tee_shm_op_release() */
	refcount_inc(&shm->refcount);
	fd = anon_inode_getfd("tee_shm", &tee_shm_fops, shm, O_RDWR);
	if (fd < 0)
	tee_shm_put(shm);
	return fd;
	}

	/**
	* tee_shm_free() - Free shared memory
	* @shm: Handle to shared memory to free
	*/
	void tee_shm_free(struct tee_shm *shm)
	{
	tee_shm_put(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 the tee_shm was found in the IDR it must have a refcount
	* larger than 0 due to the guarantee in tee_shm_put() below. So
	* it's safe to use refcount_inc().
	*/
	if (!shm \|\| shm->ctx != ctx)
	shm = ERR_PTR(-EINVAL);
	else
	refcount_inc(&shm->refcount);
	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)
	{
	struct tee_device *teedev = shm->teedev;
	bool do_release = false;

	mutex_lock(&teedev->mutex);
	if (refcount_dec_and_test(&shm->refcount)) {
	/*
	* refcount has reached 0, we must now remove it from the
	* IDR before releasing the mutex. This will guarantee that
	* the refcount_inc() in tee_shm_get_from_id() never starts
	* from 0.
	*/
	idr_remove(&teedev->idr, shm->id);
	if (shm->ctx)
	list_del(&shm->link);
	do_release = true;
	}
	mutex_unlock(&teedev->mutex);

	if (do_release)
	tee_shm_release(teedev, shm);
	}
	EXPORT_SYMBOL_GPL(tee_shm_put);