1 files changed, 348 insertions, 0 deletions
diff --git a/drivers/accel/habanalabs/common/memory_mgr.c b/drivers/accel/habanalabs/common/memory_mgr.c
new file mode 100644
index 000000000000..0f2759e26547
--- /dev/null
+++ b/drivers/accel/habanalabs/common/memory_mgr.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2022 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+/**
+ * hl_mmap_mem_buf_get - increase the buffer refcount and return a pointer to
+ *                        the buffer descriptor.
+ *
+ * @mmg: parent unified memory manager
+ * @handle: requested buffer handle
+ *
+ * Find the buffer in the store and return a pointer to its descriptor.
+ * Increase buffer refcount. If not found - return NULL.
+ */
+struct hl_mmap_mem_buf *hl_mmap_mem_buf_get(struct hl_mem_mgr *mmg, u64 handle)
+{
+	struct hl_mmap_mem_buf *buf;
+
+	spin_lock(&mmg->lock);
+	buf = idr_find(&mmg->handles, lower_32_bits(handle >> PAGE_SHIFT));
+	if (!buf) {
+		spin_unlock(&mmg->lock);
+		dev_dbg(mmg->dev, "Buff get failed, no match to handle %#llx\n", handle);
+		return NULL;
+	}
+	kref_get(&buf->refcount);
+	spin_unlock(&mmg->lock);
+	return buf;
+}
+
+/**
+ * hl_mmap_mem_buf_destroy - destroy the unused buffer
+ *
+ * @buf: memory manager buffer descriptor
+ *
+ * Internal function, used as a final step of buffer release. Shall be invoked
+ * only when the buffer is no longer in use (removed from idr). Will call the
+ * release callback (if applicable), and free the memory.
+ */
+static void hl_mmap_mem_buf_destroy(struct hl_mmap_mem_buf *buf)
+{
+	if (buf->behavior->release)
+		buf->behavior->release(buf);
+
+	kfree(buf);
+}
+
+/**
+ * hl_mmap_mem_buf_release - release buffer
+ *
+ * @kref: kref that reached 0.
+ *
+ * Internal function, used as a kref release callback, when the last user of
+ * the buffer is released. Shall be called from an interrupt context.
+ */
+static void hl_mmap_mem_buf_release(struct kref *kref)
+{
+	struct hl_mmap_mem_buf *buf =
+		container_of(kref, struct hl_mmap_mem_buf, refcount);
+
+	spin_lock(&buf->mmg->lock);
+	idr_remove(&buf->mmg->handles, lower_32_bits(buf->handle >> PAGE_SHIFT));
+	spin_unlock(&buf->mmg->lock);
+
+	hl_mmap_mem_buf_destroy(buf);
+}
+
+/**
+ * hl_mmap_mem_buf_remove_idr_locked - remove handle from idr
+ *
+ * @kref: kref that reached 0.
+ *
+ * Internal function, used for kref put by handle. Assumes mmg lock is taken.
+ * Will remove the buffer from idr, without destroying it.
+ */
+static void hl_mmap_mem_buf_remove_idr_locked(struct kref *kref)
+{
+	struct hl_mmap_mem_buf *buf =
+		container_of(kref, struct hl_mmap_mem_buf, refcount);
+
+	idr_remove(&buf->mmg->handles, lower_32_bits(buf->handle >> PAGE_SHIFT));
+}
+
+/**
+ * hl_mmap_mem_buf_put - decrease the reference to the buffer
+ *
+ * @buf: memory manager buffer descriptor
+ *
+ * Decrease the reference to the buffer, and release it if it was the last one.
+ * Shall be called from an interrupt context.
+ */
+int hl_mmap_mem_buf_put(struct hl_mmap_mem_buf *buf)
+{
+	return kref_put(&buf->refcount, hl_mmap_mem_buf_release);
+}
+
+/**
+ * hl_mmap_mem_buf_put_handle - decrease the reference to the buffer with the
+ *                              given handle.
+ *
+ * @mmg: parent unified memory manager
+ * @handle: requested buffer handle
+ *
+ * Decrease the reference to the buffer, and release it if it was the last one.
+ * Shall not be called from an interrupt context. Return -EINVAL if handle was
+ * not found, else return the put outcome (0 or 1).
+ */
+int hl_mmap_mem_buf_put_handle(struct hl_mem_mgr *mmg, u64 handle)
+{
+	struct hl_mmap_mem_buf *buf;
+
+	spin_lock(&mmg->lock);
+	buf = idr_find(&mmg->handles, lower_32_bits(handle >> PAGE_SHIFT));
+	if (!buf) {
+		spin_unlock(&mmg->lock);
+		dev_dbg(mmg->dev,
+			 "Buff put failed, no match to handle %#llx\n", handle);
+		return -EINVAL;
+	}
+
+	if (kref_put(&buf->refcount, hl_mmap_mem_buf_remove_idr_locked)) {
+		spin_unlock(&mmg->lock);
+		hl_mmap_mem_buf_destroy(buf);
+		return 1;
+	}
+
+	spin_unlock(&mmg->lock);
+	return 0;
+}
+
+/**
+ * hl_mmap_mem_buf_alloc - allocate a new mappable buffer
+ *
+ * @mmg: parent unified memory manager
+ * @behavior: behavior object describing this buffer polymorphic behavior
+ * @gfp: gfp flags to use for the memory allocations
+ * @args: additional args passed to behavior->alloc
+ *
+ * Allocate and register a new memory buffer inside the give memory manager.
+ * Return the pointer to the new buffer on success or NULL on failure.
+ */
+struct hl_mmap_mem_buf *
+hl_mmap_mem_buf_alloc(struct hl_mem_mgr *mmg,
+		      struct hl_mmap_mem_buf_behavior *behavior, gfp_t gfp,
+		      void *args)
+{
+	struct hl_mmap_mem_buf *buf;
+	int rc;
+
+	buf = kzalloc(sizeof(*buf), gfp);
+	if (!buf)
+		return NULL;
+
+	spin_lock(&mmg->lock);
+	rc = idr_alloc(&mmg->handles, buf, 1, 0, GFP_ATOMIC);
+	spin_unlock(&mmg->lock);
+	if (rc < 0) {
+		dev_err(mmg->dev,
+			"%s: Failed to allocate IDR for a new buffer, rc=%d\n",
+			behavior->topic, rc);
+		goto free_buf;
+	}
+
+	buf->mmg = mmg;
+	buf->behavior = behavior;
+	buf->handle = (((u64)rc | buf->behavior->mem_id) << PAGE_SHIFT);
+	kref_init(&buf->refcount);
+
+	rc = buf->behavior->alloc(buf, gfp, args);
+	if (rc) {
+		dev_err(mmg->dev, "%s: Failure in buffer alloc callback %d\n",
+			behavior->topic, rc);
+		goto remove_idr;
+	}
+
+	return buf;
+
+remove_idr:
+	spin_lock(&mmg->lock);
+	idr_remove(&mmg->handles, lower_32_bits(buf->handle >> PAGE_SHIFT));
+	spin_unlock(&mmg->lock);
+free_buf:
+	kfree(buf);
+	return NULL;
+}
+
+/**
+ * hl_mmap_mem_buf_vm_close - handle mmap close
+ *
+ * @vma: the vma object for which mmap was closed.
+ *
+ * Put the memory buffer if it is no longer mapped.
+ */
+static void hl_mmap_mem_buf_vm_close(struct vm_area_struct *vma)
+{
+	struct hl_mmap_mem_buf *buf =
+		(struct hl_mmap_mem_buf *)vma->vm_private_data;
+	long new_mmap_size;
+
+	new_mmap_size = buf->real_mapped_size - (vma->vm_end - vma->vm_start);
+
+	if (new_mmap_size > 0) {
+		buf->real_mapped_size = new_mmap_size;
+		return;
+	}
+
+	atomic_set(&buf->mmap, 0);
+	hl_mmap_mem_buf_put(buf);
+	vma->vm_private_data = NULL;
+}
+
+static const struct vm_operations_struct hl_mmap_mem_buf_vm_ops = {
+	.close = hl_mmap_mem_buf_vm_close
+};
+
+/**
+ * hl_mem_mgr_mmap - map the given buffer to the user
+ *
+ * @mmg: unified memory manager
+ * @vma: the vma object for which mmap was closed.
+ * @args: additional args passed to behavior->mmap
+ *
+ * Map the buffer specified by the vma->vm_pgoff to the given vma.
+ */
+int hl_mem_mgr_mmap(struct hl_mem_mgr *mmg, struct vm_area_struct *vma,
+		    void *args)
+{
+	struct hl_mmap_mem_buf *buf;
+	u64 user_mem_size;
+	u64 handle;
+	int rc;
+
+	/* We use the page offset to hold the idr and thus we need to clear
+	 * it before doing the mmap itself
+	 */
+	handle = vma->vm_pgoff << PAGE_SHIFT;
+	vma->vm_pgoff = 0;
+
+	/* Reference was taken here */
+	buf = hl_mmap_mem_buf_get(mmg, handle);
+	if (!buf) {
+		dev_err(mmg->dev,
+			"Memory mmap failed, no match to handle %#llx\n", handle);
+		return -EINVAL;
+	}
+
+	/* Validation check */
+	user_mem_size = vma->vm_end - vma->vm_start;
+	if (user_mem_size != ALIGN(buf->mappable_size, PAGE_SIZE)) {
+		dev_err(mmg->dev,
+			"%s: Memory mmap failed, mmap VM size 0x%llx != 0x%llx allocated physical mem size\n",
+			buf->behavior->topic, user_mem_size, buf->mappable_size);
+		rc = -EINVAL;
+		goto put_mem;
+	}
+
+#ifdef _HAS_TYPE_ARG_IN_ACCESS_OK
+	if (!access_ok(VERIFY_WRITE, (void __user *)(uintptr_t)vma->vm_start,
+		       user_mem_size)) {
+#else
+	if (!access_ok((void __user *)(uintptr_t)vma->vm_start,
+		       user_mem_size)) {
+#endif
+		dev_err(mmg->dev, "%s: User pointer is invalid - 0x%lx\n",
+			buf->behavior->topic, vma->vm_start);
+
+		rc = -EINVAL;
+		goto put_mem;
+	}
+
+	if (atomic_cmpxchg(&buf->mmap, 0, 1)) {
+		dev_err(mmg->dev,
+			"%s, Memory mmap failed, already mmaped to user\n",
+			buf->behavior->topic);
+		rc = -EINVAL;
+		goto put_mem;
+	}
+
+	vma->vm_ops = &hl_mmap_mem_buf_vm_ops;
+
+	/* Note: We're transferring the memory reference to vma->vm_private_data here. */
+
+	vma->vm_private_data = buf;
+
+	rc = buf->behavior->mmap(buf, vma, args);
+	if (rc) {
+		atomic_set(&buf->mmap, 0);
+		goto put_mem;
+	}
+
+	buf->real_mapped_size = buf->mappable_size;
+	vma->vm_pgoff = handle >> PAGE_SHIFT;
+
+	return 0;
+
+put_mem:
+	hl_mmap_mem_buf_put(buf);
+	return rc;
+}
+
+/**
+ * hl_mem_mgr_init - initialize unified memory manager
+ *
+ * @dev: owner device pointer
+ * @mmg: structure to initialize
+ *
+ * Initialize an instance of unified memory manager
+ */
+void hl_mem_mgr_init(struct device *dev, struct hl_mem_mgr *mmg)
+{
+	mmg->dev = dev;
+	spin_lock_init(&mmg->lock);
+	idr_init(&mmg->handles);
+}
+
+/**
+ * hl_mem_mgr_fini - release unified memory manager
+ *
+ * @mmg: parent unified memory manager
+ *
+ * Release the unified memory manager. Shall be called from an interrupt context.
+ */
+void hl_mem_mgr_fini(struct hl_mem_mgr *mmg)
+{
+	struct hl_mmap_mem_buf *buf;
+	struct idr *idp;
+	const char *topic;
+	u32 id;
+
+	idp = &mmg->handles;
+
+	idr_for_each_entry(idp, buf, id) {
+		topic = buf->behavior->topic;
+		if (hl_mmap_mem_buf_put(buf) != 1)
+			dev_err(mmg->dev,
+				"%s: Buff handle %u for CTX is still alive\n",
+				topic, id);
+	}
+
+	/* TODO: can it happen that some buffer is still in use at this point? */
+
+	idr_destroy(&mmg->handles);
+}