1 files changed, 512 insertions, 0 deletions
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
new file mode 100644
index 000000000..673cf0359
--- /dev/null
+++ b/drivers/tee/tee_shm.c
@@ -0,0 +1,512 @@
+// 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 <linux/uaccess.h>
+#include <linux/uio.h>
+#include <linux/highmem.h>
+#include "tee_private.h"
+
+static void shm_put_kernel_pages(struct page **pages, size_t page_count)
+{
+	size_t n;
+
+	for (n = 0; n < page_count; n++)
+		put_page(pages[n]);
+}
+
+static int shm_get_kernel_pages(unsigned long start, size_t page_count,
+				struct page **pages)
+{
+	struct page *page;
+	size_t n;
+
+	if (WARN_ON_ONCE(is_vmalloc_addr((void *)start) ||
+			 is_kmap_addr((void *)start)))
+		return -EINVAL;
+
+	page = virt_to_page((void *)start);
+	for (n = 0; n < page_count; n++) {
+		pages[n] = page + n;
+		get_page(pages[n]);
+	}
+
+	return page_count;
+}
+
+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
+			shm_put_kernel_pages(shm->pages, shm->num_pages);
+
+		kfree(shm->pages);
+	}
+}
+
+static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
+{
+	if (shm->flags & TEE_SHM_POOL) {
+		teedev->pool->ops->free(teedev->pool, shm);
+	} else if (shm->flags & TEE_SHM_DYNAMIC) {
+		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 tee_shm *shm_alloc_helper(struct tee_context *ctx, size_t size,
+					size_t align, u32 flags, int id)
+{
+	struct tee_device *teedev = ctx->teedev;
+	struct tee_shm *shm;
+	void *ret;
+	int rc;
+
+	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;
+	shm->id = id;
+
+	/*
+	 * We're assigning this as it is needed if the shm is to be
+	 * registered. If this function returns OK then the caller expected
+	 * to call teedev_ctx_get() or clear shm->ctx in case it's not
+	 * needed any longer.
+	 */
+	shm->ctx = ctx;
+
+	rc = teedev->pool->ops->alloc(teedev->pool, shm, size, align);
+	if (rc) {
+		ret = ERR_PTR(rc);
+		goto err_kfree;
+	}
+
+	teedev_ctx_get(ctx);
+	return shm;
+err_kfree:
+	kfree(shm);
+err_dev_put:
+	tee_device_put(teedev);
+	return ret;
+}
+
+/**
+ * tee_shm_alloc_user_buf() - Allocate shared memory for user space
+ * @ctx:	Context that allocates the shared memory
+ * @size:	Requested size of shared memory
+ *
+ * Memory allocated as user space shared memory is automatically freed when
+ * the TEE file pointer is closed. The primary usage of this function is
+ * when the TEE driver doesn't support registering ordinary user space
+ * memory.
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size)
+{
+	u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL;
+	struct tee_device *teedev = ctx->teedev;
+	struct tee_shm *shm;
+	void *ret;
+	int id;
+
+	mutex_lock(&teedev->mutex);
+	id = idr_alloc(&teedev->idr, NULL, 1, 0, GFP_KERNEL);
+	mutex_unlock(&teedev->mutex);
+	if (id < 0)
+		return ERR_PTR(id);
+
+	shm = shm_alloc_helper(ctx, size, PAGE_SIZE, flags, id);
+	if (IS_ERR(shm)) {
+		mutex_lock(&teedev->mutex);
+		idr_remove(&teedev->idr, id);
+		mutex_unlock(&teedev->mutex);
+		return shm;
+	}
+
+	mutex_lock(&teedev->mutex);
+	ret = idr_replace(&teedev->idr, shm, id);
+	mutex_unlock(&teedev->mutex);
+	if (IS_ERR(ret)) {
+		tee_shm_free(shm);
+		return ret;
+	}
+
+	return shm;
+}
+
+/**
+ * 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)
+{
+	u32 flags = TEE_SHM_DYNAMIC | TEE_SHM_POOL;
+
+	return shm_alloc_helper(ctx, size, PAGE_SIZE, flags, -1);
+}
+EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
+
+/**
+ * tee_shm_alloc_priv_buf() - Allocate shared memory for a privately shared
+ *			      kernel buffer
+ * @ctx:	Context that allocates the shared memory
+ * @size:	Requested size of shared memory
+ *
+ * This function returns similar shared memory as
+ * tee_shm_alloc_kernel_buf(), but with the difference that the memory
+ * might not be registered in secure world in case the driver supports
+ * passing memory not registered in advance.
+ *
+ * This function should normally only be used internally in the TEE
+ * drivers.
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size)
+{
+	u32 flags = TEE_SHM_PRIV | TEE_SHM_POOL;
+
+	return shm_alloc_helper(ctx, size, sizeof(long) * 2, flags, -1);
+}
+EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
+
+static struct tee_shm *
+register_shm_helper(struct tee_context *ctx, unsigned long addr,
+		    size_t length, u32 flags, int id)
+{
+	struct tee_device *teedev = ctx->teedev;
+	struct tee_shm *shm;
+	unsigned long start;
+	size_t num_pages;
+	void *ret;
+	int rc;
+
+	if (!tee_device_get(teedev))
+		return ERR_PTR(-EINVAL);
+
+	if (!teedev->desc->ops->shm_register ||
+	    !teedev->desc->ops->shm_unregister) {
+		ret = ERR_PTR(-ENOTSUPP);
+		goto err_dev_put;
+	}
+
+	teedev_ctx_get(ctx);
+
+	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
+	if (!shm) {
+		ret = ERR_PTR(-ENOMEM);
+		goto err_ctx_put;
+	}
+
+	refcount_set(&shm->refcount, 1);
+	shm->flags = flags;
+	shm->ctx = ctx;
+	shm->id = id;
+	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_free_shm;
+	}
+
+	if (flags & TEE_SHM_USER_MAPPED)
+		rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,
+					 shm->pages);
+	else
+		rc = shm_get_kernel_pages(start, num_pages, shm->pages);
+	if (rc > 0)
+		shm->num_pages = rc;
+	if (rc != num_pages) {
+		if (rc >= 0)
+			rc = -ENOMEM;
+		ret = ERR_PTR(rc);
+		goto err_put_shm_pages;
+	}
+
+	rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
+					     shm->num_pages, start);
+	if (rc) {
+		ret = ERR_PTR(rc);
+		goto err_put_shm_pages;
+	}
+
+	return shm;
+err_put_shm_pages:
+	if (flags & TEE_SHM_USER_MAPPED)
+		unpin_user_pages(shm->pages, shm->num_pages);
+	else
+		shm_put_kernel_pages(shm->pages, shm->num_pages);
+	kfree(shm->pages);
+err_free_shm:
+	kfree(shm);
+err_ctx_put:
+	teedev_ctx_put(ctx);
+err_dev_put:
+	tee_device_put(teedev);
+	return ret;
+}
+
+/**
+ * tee_shm_register_user_buf() - Register a userspace shared memory buffer
+ * @ctx:	Context that registers the shared memory
+ * @addr:	The userspace address of the shared buffer
+ * @length:	Length of the shared buffer
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
+					  unsigned long addr, size_t length)
+{
+	u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC;
+	struct tee_device *teedev = ctx->teedev;
+	struct tee_shm *shm;
+	void *ret;
+	int id;
+
+	if (!access_ok((void __user *)addr, length))
+		return ERR_PTR(-EFAULT);
+
+	mutex_lock(&teedev->mutex);
+	id = idr_alloc(&teedev->idr, NULL, 1, 0, GFP_KERNEL);
+	mutex_unlock(&teedev->mutex);
+	if (id < 0)
+		return ERR_PTR(id);
+
+	shm = register_shm_helper(ctx, addr, length, flags, id);
+	if (IS_ERR(shm)) {
+		mutex_lock(&teedev->mutex);
+		idr_remove(&teedev->idr, id);
+		mutex_unlock(&teedev->mutex);
+		return shm;
+	}
+
+	mutex_lock(&teedev->mutex);
+	ret = idr_replace(&teedev->idr, shm, id);
+	mutex_unlock(&teedev->mutex);
+	if (IS_ERR(ret)) {
+		tee_shm_free(shm);
+		return ret;
+	}
+
+	return shm;
+}
+
+/**
+ * tee_shm_register_kernel_buf() - Register kernel memory to be shared with
+ *				   secure world
+ * @ctx:	Context that registers the shared memory
+ * @addr:	The buffer
+ * @length:	Length of the buffer
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+
+struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
+					    void *addr, size_t length)
+{
+	u32 flags = TEE_SHM_DYNAMIC;
+
+	return register_shm_helper(ctx, (unsigned long)addr, length, flags, -1);
+}
+EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf);
+
+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->id < 0)
+		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_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->kaddr)
+		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->ctx->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.
+		 */
+		if (shm->id >= 0)
+			idr_remove(&teedev->idr, shm->id);
+		do_release = true;
+	}
+	mutex_unlock(&teedev->mutex);
+
+	if (do_release)
+		tee_shm_release(teedev, shm);
+}
+EXPORT_SYMBOL_GPL(tee_shm_put);