1 files changed, 462 insertions, 0 deletions
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
new file mode 100644
index 000000000..5fd5aa5f0
--- /dev/null
+++ b/drivers/tee/tee_shm.c
@@ -0,0 +1,462 @@
+/*
+ * Copyright (c) 2015-2017, 2019-2021 Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#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))) {
+		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);
+
+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;
+	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, 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);