Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1184 insertions, 0 deletions

diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c
new file mode 100644
index 000000000..cd47b627f
--- /dev/null
+++ b/drivers/thunderbolt/ctl.c
@@ -0,0 +1,1184 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt driver - control channel and configuration commands
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ * Copyright (C) 2018, Intel Corporation
+ */
+
+#include <linux/crc32.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/dmapool.h>
+#include <linux/workqueue.h>
+
+#include "ctl.h"
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+#define TB_CTL_RX_PKG_COUNT	10
+#define TB_CTL_RETRIES		4
+
+/**
+ * struct tb_ctl - Thunderbolt control channel
+ * @nhi: Pointer to the NHI structure
+ * @tx: Transmit ring
+ * @rx: Receive ring
+ * @frame_pool: DMA pool for control messages
+ * @rx_packets: Received control messages
+ * @request_queue_lock: Lock protecting @request_queue
+ * @request_queue: List of outstanding requests
+ * @running: Is the control channel running at the moment
+ * @timeout_msec: Default timeout for non-raw control messages
+ * @callback: Callback called when hotplug message is received
+ * @callback_data: Data passed to @callback
+ * @index: Domain number. This will be output with the trace record.
+ */
+struct tb_ctl {
+	struct tb_nhi *nhi;
+	struct tb_ring *tx;
+	struct tb_ring *rx;
+
+	struct dma_pool *frame_pool;
+	struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
+	struct mutex request_queue_lock;
+	struct list_head request_queue;
+	bool running;
+
+	int timeout_msec;
+	event_cb callback;
+	void *callback_data;
+
+	int index;
+};
+
+
+#define tb_ctl_WARN(ctl, format, arg...) \
+	dev_WARN((ctl)->nhi->dev, format, ## arg)
+
+#define tb_ctl_err(ctl, format, arg...) \
+	dev_err((ctl)->nhi->dev, format, ## arg)
+
+#define tb_ctl_warn(ctl, format, arg...) \
+	dev_warn((ctl)->nhi->dev, format, ## arg)
+
+#define tb_ctl_info(ctl, format, arg...) \
+	dev_info((ctl)->nhi->dev, format, ## arg)
+
+#define tb_ctl_dbg(ctl, format, arg...) \
+	dev_dbg((ctl)->nhi->dev, format, ## arg)
+
+#define tb_ctl_dbg_once(ctl, format, arg...) \
+	dev_dbg_once((ctl)->nhi->dev, format, ## arg)
+
+static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
+/* Serializes access to request kref_get/put */
+static DEFINE_MUTEX(tb_cfg_request_lock);
+
+/**
+ * tb_cfg_request_alloc() - Allocates a new config request
+ *
+ * This is refcounted object so when you are done with this, call
+ * tb_cfg_request_put() to it.
+ *
+ * Return: &struct tb_cfg_request on success, %NULL otherwise.
+ */
+struct tb_cfg_request *tb_cfg_request_alloc(void)
+{
+	struct tb_cfg_request *req;
+
+	req = kzalloc_obj(*req);
+	if (!req)
+		return NULL;
+
+	kref_init(&req->kref);
+
+	return req;
+}
+
+/**
+ * tb_cfg_request_get() - Increase refcount of a request
+ * @req: Request whose refcount is increased
+ */
+void tb_cfg_request_get(struct tb_cfg_request *req)
+{
+	mutex_lock(&tb_cfg_request_lock);
+	kref_get(&req->kref);
+	mutex_unlock(&tb_cfg_request_lock);
+}
+
+static void tb_cfg_request_destroy(struct kref *kref)
+{
+	struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);
+
+	kfree(req);
+}
+
+/**
+ * tb_cfg_request_put() - Decrease refcount and possibly release the request
+ * @req: Request whose refcount is decreased
+ *
+ * Call this function when you are done with the request. When refcount
+ * goes to %0 the object is released.
+ */
+void tb_cfg_request_put(struct tb_cfg_request *req)
+{
+	mutex_lock(&tb_cfg_request_lock);
+	kref_put(&req->kref, tb_cfg_request_destroy);
+	mutex_unlock(&tb_cfg_request_lock);
+}
+
+static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
+				  struct tb_cfg_request *req)
+{
+	WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
+	WARN_ON(req->ctl);
+
+	mutex_lock(&ctl->request_queue_lock);
+	if (!ctl->running) {
+		mutex_unlock(&ctl->request_queue_lock);
+		return -ENOTCONN;
+	}
+	req->ctl = ctl;
+	list_add_tail(&req->list, &ctl->request_queue);
+	set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
+	mutex_unlock(&ctl->request_queue_lock);
+	return 0;
+}
+
+static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
+{
+	struct tb_ctl *ctl = req->ctl;
+
+	mutex_lock(&ctl->request_queue_lock);
+	if (!test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags)) {
+		mutex_unlock(&ctl->request_queue_lock);
+		return;
+	}
+
+	list_del(&req->list);
+	clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
+	if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
+		wake_up(&tb_cfg_request_cancel_queue);
+	mutex_unlock(&ctl->request_queue_lock);
+}
+
+static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
+{
+	return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
+}
+
+static struct tb_cfg_request *
+tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
+{
+	struct tb_cfg_request *req = NULL, *iter;
+
+	mutex_lock(&pkg->ctl->request_queue_lock);
+	list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
+		tb_cfg_request_get(iter);
+		if (iter->match(iter, pkg)) {
+			req = iter;
+			break;
+		}
+		tb_cfg_request_put(iter);
+	}
+	mutex_unlock(&pkg->ctl->request_queue_lock);
+
+	return req;
+}
+
+/* utility functions */
+
+
+static int check_header(const struct ctl_pkg *pkg, u32 len,
+			enum tb_cfg_pkg_type type, u64 route)
+{
+	struct tb_cfg_header *header = pkg->buffer;
+
+	/* check frame, TODO: frame flags */
+	if (WARN(len != pkg->frame.size,
+			"wrong framesize (expected %#x, got %#x)\n",
+			len, pkg->frame.size))
+		return -EIO;
+	if (WARN(type != pkg->frame.eof, "wrong eof (expected %#x, got %#x)\n",
+			type, pkg->frame.eof))
+		return -EIO;
+	if (WARN(pkg->frame.sof, "wrong sof (expected 0x0, got %#x)\n",
+			pkg->frame.sof))
+		return -EIO;
+
+	/* check header */
+	if (WARN(header->unknown != 1 << 9,
+			"header->unknown is %#x\n", header->unknown))
+		return -EIO;
+	if (WARN(route != tb_cfg_get_route(header),
+			"wrong route (expected %llx, got %llx)",
+			route, tb_cfg_get_route(header)))
+		return -EIO;
+	return 0;
+}
+
+static int check_config_address(struct tb_cfg_address addr,
+				enum tb_cfg_space space, u32 offset,
+				u32 length)
+{
+	if (WARN(addr.zero, "addr.zero is %#x\n", addr.zero))
+		return -EIO;
+	if (WARN(space != addr.space, "wrong space (expected %x, got %x\n)",
+			space, addr.space))
+		return -EIO;
+	if (WARN(offset != addr.offset, "wrong offset (expected %x, got %x\n)",
+			offset, addr.offset))
+		return -EIO;
+	if (WARN(length != addr.length, "wrong space (expected %x, got %x\n)",
+			length, addr.length))
+		return -EIO;
+	/*
+	 * We cannot check addr->port as it is set to the upstream port of the
+	 * sender.
+	 */
+	return 0;
+}
+
+static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
+{
+	struct cfg_error_pkg *pkg = response->buffer;
+	struct tb_cfg_result res = { 0 };
+	res.response_route = tb_cfg_get_route(&pkg->header);
+	res.response_port = 0;
+	res.err = check_header(response, sizeof(*pkg), TB_CFG_PKG_ERROR,
+			       tb_cfg_get_route(&pkg->header));
+	if (res.err)
+		return res;
+
+	res.err = 1;
+	res.tb_error = pkg->error;
+	res.response_port = pkg->port;
+	return res;
+
+}
+
+static struct tb_cfg_result parse_header(const struct ctl_pkg *pkg, u32 len,
+					 enum tb_cfg_pkg_type type, u64 route)
+{
+	struct tb_cfg_header *header = pkg->buffer;
+	struct tb_cfg_result res = { 0 };
+
+	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
+		return decode_error(pkg);
+
+	res.response_port = 0; /* will be updated later for cfg_read/write */
+	res.response_route = tb_cfg_get_route(header);
+	res.err = check_header(pkg, len, type, route);
+	return res;
+}
+
+static void tb_cfg_print_error(struct tb_ctl *ctl, enum tb_cfg_space space,
+			       const struct tb_cfg_result *res)
+{
+	WARN_ON(res->err != 1);
+	switch (res->tb_error) {
+	case TB_CFG_ERROR_PORT_NOT_CONNECTED:
+		/* Port is not connected. This can happen during surprise
+		 * removal. Do not warn. */
+		return;
+	case TB_CFG_ERROR_INVALID_CONFIG_SPACE:
+		/*
+		 * Invalid cfg_space/offset/length combination in
+		 * cfg_read/cfg_write.
+		 */
+		tb_ctl_dbg_once(ctl, "%llx:%x: invalid config space (%u) or offset\n",
+				res->response_route, res->response_port, space);
+		return;
+	case TB_CFG_ERROR_NO_SUCH_PORT:
+		/*
+		 * - The route contains a non-existent port.
+		 * - The route contains a non-PHY port (e.g. PCIe).
+		 * - The port in cfg_read/cfg_write does not exist.
+		 */
+		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Invalid port\n",
+			res->response_route, res->response_port);
+		return;
+	case TB_CFG_ERROR_LOOP:
+		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
+			res->response_route, res->response_port);
+		return;
+	case TB_CFG_ERROR_LOCK:
+		tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
+			    res->response_route, res->response_port);
+		return;
+	default:
+		/* 5,6,7,9 and 11 are also valid error codes */
+		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
+			res->response_route, res->response_port);
+		return;
+	}
+}
+
+static __be32 tb_crc(const void *data, size_t len)
+{
+	return cpu_to_be32(~crc32c(~0, data, len));
+}
+
+static void tb_ctl_pkg_free(struct ctl_pkg *pkg)
+{
+	if (pkg) {
+		dma_pool_free(pkg->ctl->frame_pool,
+			      pkg->buffer, pkg->frame.buffer_phy);
+		kfree(pkg);
+	}
+}
+
+static struct ctl_pkg *tb_ctl_pkg_alloc(struct tb_ctl *ctl)
+{
+	struct ctl_pkg *pkg = kzalloc_obj(*pkg);
+	if (!pkg)
+		return NULL;
+	pkg->ctl = ctl;
+	pkg->buffer = dma_pool_alloc(ctl->frame_pool, GFP_KERNEL,
+				     &pkg->frame.buffer_phy);
+	if (!pkg->buffer) {
+		kfree(pkg);
+		return NULL;
+	}
+	return pkg;
+}
+
+
+/* RX/TX handling */
+
+static void tb_ctl_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
+			       bool canceled)
+{
+	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
+	tb_ctl_pkg_free(pkg);
+}
+
+/*
+ * tb_cfg_tx() - transmit a packet on the control channel
+ *
+ * len must be a multiple of four.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
+		     enum tb_cfg_pkg_type type)
+{
+	int res;
+	struct ctl_pkg *pkg;
+	if (len % 4 != 0) { /* required for le->be conversion */
+		tb_ctl_WARN(ctl, "TX: invalid size: %zu\n", len);
+		return -EINVAL;
+	}
+	if (len > TB_FRAME_SIZE - 4) { /* checksum is 4 bytes */
+		tb_ctl_WARN(ctl, "TX: packet too large: %zu/%d\n",
+			    len, TB_FRAME_SIZE - 4);
+		return -EINVAL;
+	}
+	pkg = tb_ctl_pkg_alloc(ctl);
+	if (!pkg)
+		return -ENOMEM;
+	pkg->frame.callback = tb_ctl_tx_callback;
+	pkg->frame.size = len + 4;
+	pkg->frame.sof = type;
+	pkg->frame.eof = type;
+
+	trace_tb_tx(ctl->index, type, data, len);
+
+	cpu_to_be32_array(pkg->buffer, data, len / 4);
+	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
+
+	res = tb_ring_tx(ctl->tx, &pkg->frame);
+	if (res) /* ring is stopped */
+		tb_ctl_pkg_free(pkg);
+	return res;
+}
+
+/*
+ * tb_ctl_handle_event() - acknowledge a plug event, invoke ctl->callback
+ */
+static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
+				struct ctl_pkg *pkg, size_t size)
+{
+	trace_tb_event(ctl->index, type, pkg->buffer, size);
+	return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
+}
+
+static void tb_ctl_rx_submit(struct ctl_pkg *pkg)
+{
+	tb_ring_rx(pkg->ctl->rx, &pkg->frame); /*
+					     * We ignore failures during stop.
+					     * All rx packets are referenced
+					     * from ctl->rx_packets, so we do
+					     * not lose them.
+					     */
+}
+
+static int tb_async_error(const struct ctl_pkg *pkg)
+{
+	const struct cfg_error_pkg *error = pkg->buffer;
+
+	if (pkg->frame.eof != TB_CFG_PKG_ERROR)
+		return false;
+
+	switch (error->error) {
+	case TB_CFG_ERROR_LINK_ERROR:
+	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
+	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
+	case TB_CFG_ERROR_DP_BW:
+	case TB_CFG_ERROR_ROP_CMPLT:
+	case TB_CFG_ERROR_POP_CMPLT:
+	case TB_CFG_ERROR_PCIE_WAKE:
+	case TB_CFG_ERROR_DP_CON_CHANGE:
+	case TB_CFG_ERROR_DPTX_DISCOVERY:
+	case TB_CFG_ERROR_LINK_RECOVERY:
+	case TB_CFG_ERROR_ASYM_LINK:
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
+			       bool canceled)
+{
+	struct ctl_pkg *pkg = container_of(frame, typeof(*pkg), frame);
+	struct tb_cfg_request *req;
+	__be32 crc32;
+
+	if (canceled)
+		return; /*
+			 * ring is stopped, packet is referenced from
+			 * ctl->rx_packets.
+			 */
+
+	if (frame->size < 4 || frame->size % 4 != 0) {
+		tb_ctl_err(pkg->ctl, "RX: invalid size %#x, dropping packet\n",
+			   frame->size);
+		goto rx;
+	}
+
+	frame->size -= 4; /* remove checksum */
+	crc32 = tb_crc(pkg->buffer, frame->size);
+	be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
+
+	switch (frame->eof) {
+	case TB_CFG_PKG_READ:
+	case TB_CFG_PKG_WRITE:
+	case TB_CFG_PKG_ERROR:
+	case TB_CFG_PKG_OVERRIDE:
+	case TB_CFG_PKG_RESET:
+		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
+			tb_ctl_err(pkg->ctl,
+				   "RX: checksum mismatch, dropping packet\n");
+			goto rx;
+		}
+		if (tb_async_error(pkg)) {
+			tb_ctl_handle_event(pkg->ctl, frame->eof,
+					    pkg, frame->size);
+			goto rx;
+		}
+		break;
+
+	case TB_CFG_PKG_EVENT:
+	case TB_CFG_PKG_XDOMAIN_RESP:
+	case TB_CFG_PKG_XDOMAIN_REQ:
+		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
+			tb_ctl_err(pkg->ctl,
+				   "RX: checksum mismatch, dropping packet\n");
+			goto rx;
+		}
+		fallthrough;
+	case TB_CFG_PKG_ICM_EVENT:
+		if (tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size))
+			goto rx;
+		break;
+
+	default:
+		break;
+	}
+
+	/*
+	 * The received packet will be processed only if there is an
+	 * active request and that the packet is what is expected. This
+	 * prevents packets such as replies coming after timeout has
+	 * triggered from messing with the active requests.
+	 */
+	req = tb_cfg_request_find(pkg->ctl, pkg);
+
+	trace_tb_rx(pkg->ctl->index, frame->eof, pkg->buffer, frame->size, !req);
+
+	if (req) {
+		if (req->copy(req, pkg))
+			schedule_work(&req->work);
+		tb_cfg_request_put(req);
+	}
+
+rx:
+	tb_ctl_rx_submit(pkg);
+}
+
+static void tb_cfg_request_work(struct work_struct *work)
+{
+	struct tb_cfg_request *req = container_of(work, typeof(*req), work);
+
+	if (!test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
+		req->callback(req->callback_data);
+
+	tb_cfg_request_dequeue(req);
+	tb_cfg_request_put(req);
+}
+
+/**
+ * tb_cfg_request() - Start control request not waiting for it to complete
+ * @ctl: Control channel to use
+ * @req: Request to start
+ * @callback: Callback called when the request is completed
+ * @callback_data: Data to be passed to @callback
+ *
+ * This queues @req on the given control channel without waiting for it
+ * to complete. When the request completes @callback is called.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_cfg_request(struct tb_ctl *ctl, struct tb_cfg_request *req,
+		   void (*callback)(void *), void *callback_data)
+{
+	int ret;
+
+	req->flags = 0;
+	req->callback = callback;
+	req->callback_data = callback_data;
+	INIT_WORK(&req->work, tb_cfg_request_work);
+	INIT_LIST_HEAD(&req->list);
+
+	tb_cfg_request_get(req);
+	ret = tb_cfg_request_enqueue(ctl, req);
+	if (ret)
+		goto err_put;
+
+	ret = tb_ctl_tx(ctl, req->request, req->request_size,
+			req->request_type);
+	if (ret)
+		goto err_dequeue;
+
+	if (!req->response)
+		schedule_work(&req->work);
+
+	return 0;
+
+err_dequeue:
+	tb_cfg_request_dequeue(req);
+err_put:
+	tb_cfg_request_put(req);
+
+	return ret;
+}
+
+/**
+ * tb_cfg_request_cancel() - Cancel a control request
+ * @req: Request to cancel
+ * @err: Error to assign to the request
+ *
+ * This function can be used to cancel ongoing request. It will wait
+ * until the request is not active anymore.
+ */
+void tb_cfg_request_cancel(struct tb_cfg_request *req, int err)
+{
+	set_bit(TB_CFG_REQUEST_CANCELED, &req->flags);
+	schedule_work(&req->work);
+	wait_event(tb_cfg_request_cancel_queue, !tb_cfg_request_is_active(req));
+	req->result.err = err;
+}
+
+static void tb_cfg_request_complete(void *data)
+{
+	complete(data);
+}
+
+/**
+ * tb_cfg_request_sync() - Start control request and wait until it completes
+ * @ctl: Control channel to use
+ * @req: Request to start
+ * @timeout_msec: Timeout how long to wait @req to complete
+ *
+ * Starts a control request and waits until it completes. If timeout
+ * triggers the request is canceled before function returns. Note the
+ * caller needs to make sure only one message for given switch is active
+ * at a time.
+ *
+ * Return: &struct tb_cfg_result with non-zero @err field if error
+ * has occurred.
+ */
+struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
+					 struct tb_cfg_request *req,
+					 int timeout_msec)
+{
+	unsigned long timeout = msecs_to_jiffies(timeout_msec);
+	struct tb_cfg_result res = { 0 };
+	DECLARE_COMPLETION_ONSTACK(done);
+	int ret;
+
+	ret = tb_cfg_request(ctl, req, tb_cfg_request_complete, &done);
+	if (ret) {
+		res.err = ret;
+		return res;
+	}
+
+	if (!wait_for_completion_timeout(&done, timeout))
+		tb_cfg_request_cancel(req, -ETIMEDOUT);
+
+	flush_work(&req->work);
+
+	return req->result;
+}
+
+/* public interface, alloc/start/stop/free */
+
+/**
+ * tb_ctl_alloc() - allocate a control channel
+ * @nhi: Pointer to NHI
+ * @index: Domain number
+ * @timeout_msec: Default timeout used with non-raw control messages
+ * @cb: Callback called for plug events
+ * @cb_data: Data passed to @cb
+ *
+ * cb will be invoked once for every hot plug event.
+ *
+ * Return: Pointer to &struct tb_ctl, %NULL on failure.
+ */
+struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int index, int timeout_msec,
+			    event_cb cb, void *cb_data)
+{
+	int i;
+	struct tb_ctl *ctl = kzalloc_obj(*ctl);
+	if (!ctl)
+		return NULL;
+
+	ctl->nhi = nhi;
+	ctl->index = index;
+	ctl->timeout_msec = timeout_msec;
+	ctl->callback = cb;
+	ctl->callback_data = cb_data;
+
+	mutex_init(&ctl->request_queue_lock);
+	INIT_LIST_HEAD(&ctl->request_queue);
+	ctl->frame_pool = dma_pool_create("thunderbolt_ctl", nhi->dev,
+					  TB_FRAME_SIZE, 4, 0);
+	if (!ctl->frame_pool)
+		goto err;
+
+	ctl->tx = tb_ring_alloc_tx(nhi, 0, 10, RING_FLAG_NO_SUSPEND);
+	if (!ctl->tx)
+		goto err;
+
+	ctl->rx = tb_ring_alloc_rx(nhi, 0, 10, RING_FLAG_NO_SUSPEND, 0, 0xffff,
+				   0xffff, NULL, NULL);
+	if (!ctl->rx)
+		goto err;
+
+	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++) {
+		ctl->rx_packets[i] = tb_ctl_pkg_alloc(ctl);
+		if (!ctl->rx_packets[i])
+			goto err;
+		ctl->rx_packets[i]->frame.callback = tb_ctl_rx_callback;
+	}
+
+	tb_ctl_dbg(ctl, "control channel created\n");
+	return ctl;
+err:
+	tb_ctl_free(ctl);
+	return NULL;
+}
+
+/**
+ * tb_ctl_free() - free a control channel
+ * @ctl: Control channel to free
+ *
+ * Must be called after tb_ctl_stop.
+ *
+ * Must NOT be called from ctl->callback.
+ */
+void tb_ctl_free(struct tb_ctl *ctl)
+{
+	int i;
+
+	if (!ctl)
+		return;
+
+	if (ctl->rx)
+		tb_ring_free(ctl->rx);
+	if (ctl->tx)
+		tb_ring_free(ctl->tx);
+
+	/* free RX packets */
+	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
+		tb_ctl_pkg_free(ctl->rx_packets[i]);
+
+
+	dma_pool_destroy(ctl->frame_pool);
+	kfree(ctl);
+}
+
+/**
+ * tb_ctl_start() - start/resume the control channel
+ * @ctl: Control channel to start
+ */
+void tb_ctl_start(struct tb_ctl *ctl)
+{
+	int i;
+	tb_ctl_dbg(ctl, "control channel starting...\n");
+	tb_ring_start(ctl->tx); /* is used to ack hotplug packets, start first */
+	tb_ring_start(ctl->rx);
+	for (i = 0; i < TB_CTL_RX_PKG_COUNT; i++)
+		tb_ctl_rx_submit(ctl->rx_packets[i]);
+
+	ctl->running = true;
+}
+
+/**
+ * tb_ctl_stop() - pause the control channel
+ * @ctl: Control channel to stop
+ *
+ * All invocations of ctl->callback will have finished after this method
+ * returns.
+ *
+ * Must NOT be called from ctl->callback.
+ */
+void tb_ctl_stop(struct tb_ctl *ctl)
+{
+	mutex_lock(&ctl->request_queue_lock);
+	ctl->running = false;
+	mutex_unlock(&ctl->request_queue_lock);
+
+	tb_ring_stop(ctl->rx);
+	tb_ring_stop(ctl->tx);
+
+	if (!list_empty(&ctl->request_queue))
+		tb_ctl_WARN(ctl, "dangling request in request_queue\n");
+	INIT_LIST_HEAD(&ctl->request_queue);
+	tb_ctl_dbg(ctl, "control channel stopped\n");
+}
+
+/* public interface, commands */
+
+/**
+ * tb_cfg_ack_notification() - Ack notification
+ * @ctl: Control channel to use
+ * @route: Router that originated the event
+ * @error: Pointer to the notification package
+ *
+ * Call this as a response for non-plug notification to ack it.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_cfg_ack_notification(struct tb_ctl *ctl, u64 route,
+			    const struct cfg_error_pkg *error)
+{
+	struct cfg_ack_pkg pkg = {
+		.header = tb_cfg_make_header(route),
+	};
+	const char *name;
+
+	switch (error->error) {
+	case TB_CFG_ERROR_LINK_ERROR:
+		name = "link error";
+		break;
+	case TB_CFG_ERROR_HEC_ERROR_DETECTED:
+		name = "HEC error";
+		break;
+	case TB_CFG_ERROR_FLOW_CONTROL_ERROR:
+		name = "flow control error";
+		break;
+	case TB_CFG_ERROR_DP_BW:
+		name = "DP_BW";
+		break;
+	case TB_CFG_ERROR_ROP_CMPLT:
+		name = "router operation completion";
+		break;
+	case TB_CFG_ERROR_POP_CMPLT:
+		name = "port operation completion";
+		break;
+	case TB_CFG_ERROR_PCIE_WAKE:
+		name = "PCIe wake";
+		break;
+	case TB_CFG_ERROR_DP_CON_CHANGE:
+		name = "DP connector change";
+		break;
+	case TB_CFG_ERROR_DPTX_DISCOVERY:
+		name = "DPTX discovery";
+		break;
+	case TB_CFG_ERROR_LINK_RECOVERY:
+		name = "link recovery";
+		break;
+	case TB_CFG_ERROR_ASYM_LINK:
+		name = "asymmetric link";
+		break;
+	default:
+		name = "unknown";
+		break;
+	}
+
+	tb_ctl_dbg(ctl, "acking %s (%#x) notification on %llx\n", name,
+		   error->error, route);
+
+	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_NOTIFY_ACK);
+}
+
+/**
+ * tb_cfg_ack_plug() - Ack hot plug/unplug event
+ * @ctl: Control channel to use
+ * @route: Router that originated the event
+ * @port: Port where the hot plug/unplug happened
+ * @unplug: Ack hot plug or unplug
+ *
+ * Call this as a response for hot plug/unplug event to ack it.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_cfg_ack_plug(struct tb_ctl *ctl, u64 route, u32 port, bool unplug)
+{
+	struct cfg_error_pkg pkg = {
+		.header = tb_cfg_make_header(route),
+		.port = port,
+		.error = TB_CFG_ERROR_ACK_PLUG_EVENT,
+		.pg = unplug ? TB_CFG_ERROR_PG_HOT_UNPLUG
+			     : TB_CFG_ERROR_PG_HOT_PLUG,
+	};
+	tb_ctl_dbg(ctl, "acking hot %splug event on %llx:%u\n",
+		   unplug ? "un" : "", route, port);
+	return tb_ctl_tx(ctl, &pkg, sizeof(pkg), TB_CFG_PKG_ERROR);
+}
+
+static bool tb_cfg_match(const struct tb_cfg_request *req,
+			 const struct ctl_pkg *pkg)
+{
+	u64 route = tb_cfg_get_route(pkg->buffer) & ~BIT_ULL(63);
+
+	if (pkg->frame.eof == TB_CFG_PKG_ERROR)
+		return true;
+
+	if (pkg->frame.eof != req->response_type)
+		return false;
+	if (route != tb_cfg_get_route(req->request))
+		return false;
+	if (pkg->frame.size != req->response_size)
+		return false;
+
+	if (pkg->frame.eof == TB_CFG_PKG_READ ||
+	    pkg->frame.eof == TB_CFG_PKG_WRITE) {
+		const struct cfg_read_pkg *req_hdr = req->request;
+		const struct cfg_read_pkg *res_hdr = pkg->buffer;
+
+		if (req_hdr->addr.seq != res_hdr->addr.seq)
+			return false;
+	}
+
+	return true;
+}
+
+static bool tb_cfg_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
+{
+	struct tb_cfg_result res;
+
+	/* Now make sure it is in expected format */
+	res = parse_header(pkg, req->response_size, req->response_type,
+			   tb_cfg_get_route(req->request));
+	if (!res.err)
+		memcpy(req->response, pkg->buffer, req->response_size);
+
+	req->result = res;
+
+	/* Always complete when first response is received */
+	return true;
+}
+
+/**
+ * tb_cfg_reset() - send a reset packet and wait for a response
+ * @ctl: Control channel pointer
+ * @route: Router string for the router to send reset
+ *
+ * If the switch at route is incorrectly configured then we will not receive a
+ * reply (even though the switch will reset). The caller should check for
+ * -ETIMEDOUT and attempt to reconfigure the switch.
+ *
+ * Return: &struct tb_cfg_result with non-zero @err field if error
+ * has occurred.
+ */
+struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route)
+{
+	struct cfg_reset_pkg request = { .header = tb_cfg_make_header(route) };
+	struct tb_cfg_result res = { 0 };
+	struct tb_cfg_header reply;
+	struct tb_cfg_request *req;
+
+	req = tb_cfg_request_alloc();
+	if (!req) {
+		res.err = -ENOMEM;
+		return res;
+	}
+
+	req->match = tb_cfg_match;
+	req->copy = tb_cfg_copy;
+	req->request = &request;
+	req->request_size = sizeof(request);
+	req->request_type = TB_CFG_PKG_RESET;
+	req->response = &reply;
+	req->response_size = sizeof(reply);
+	req->response_type = TB_CFG_PKG_RESET;
+
+	res = tb_cfg_request_sync(ctl, req, ctl->timeout_msec);
+
+	tb_cfg_request_put(req);
+
+	return res;
+}
+
+/**
+ * tb_cfg_read_raw() - read from config space into buffer
+ * @ctl: Pointer to the control channel
+ * @buffer: Buffer where the data is read
+ * @route: Route string of the router
+ * @port: Port number when reading from %TB_CFG_PORT, %0 otherwise
+ * @space: Config space selector
+ * @offset: Dword word offset of the register to start reading
+ * @length: Number of dwords to read
+ * @timeout_msec: Timeout in ms how long to wait for the response
+ *
+ * Reads from router config space without translating the possible error.
+ *
+ * Return: &struct tb_cfg_result with non-zero @err field if error
+ * has occurred.
+ */
+struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
+		u64 route, u32 port, enum tb_cfg_space space,
+		u32 offset, u32 length, int timeout_msec)
+{
+	struct tb_cfg_result res = { 0 };
+	struct cfg_read_pkg request = {
+		.header = tb_cfg_make_header(route),
+		.addr = {
+			.port = port,
+			.space = space,
+			.offset = offset,
+			.length = length,
+		},
+	};
+	struct cfg_write_pkg reply;
+	int retries = 0;
+
+	while (retries < TB_CTL_RETRIES) {
+		struct tb_cfg_request *req;
+
+		req = tb_cfg_request_alloc();
+		if (!req) {
+			res.err = -ENOMEM;
+			return res;
+		}
+
+		request.addr.seq = retries++;
+
+		req->match = tb_cfg_match;
+		req->copy = tb_cfg_copy;
+		req->request = &request;
+		req->request_size = sizeof(request);
+		req->request_type = TB_CFG_PKG_READ;
+		req->response = &reply;
+		req->response_size = 12 + 4 * length;
+		req->response_type = TB_CFG_PKG_READ;
+
+		res = tb_cfg_request_sync(ctl, req, timeout_msec);
+
+		tb_cfg_request_put(req);
+
+		if (res.err != -ETIMEDOUT)
+			break;
+
+		/* Wait a bit (arbitrary time) until we send a retry */
+		usleep_range(10, 100);
+	}
+
+	if (res.err)
+		return res;
+
+	res.response_port = reply.addr.port;
+	res.err = check_config_address(reply.addr, space, offset, length);
+	if (!res.err)
+		memcpy(buffer, &reply.data, 4 * length);
+	return res;
+}
+
+/**
+ * tb_cfg_write_raw() - write from buffer into config space
+ * @ctl: Pointer to the control channel
+ * @buffer: Data to write
+ * @route: Route string of the router
+ * @port: Port number when writing to %TB_CFG_PORT, %0 otherwise
+ * @space: Config space selector
+ * @offset: Dword word offset of the register to start writing
+ * @length: Number of dwords to write
+ * @timeout_msec: Timeout in ms how long to wait for the response
+ *
+ * Writes to router config space without translating the possible error.
+ *
+ * Return: &struct tb_cfg_result with non-zero @err field if error
+ * has occurred.
+ */
+struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
+		u64 route, u32 port, enum tb_cfg_space space,
+		u32 offset, u32 length, int timeout_msec)
+{
+	struct tb_cfg_result res = { 0 };
+	struct cfg_write_pkg request = {
+		.header = tb_cfg_make_header(route),
+		.addr = {
+			.port = port,
+			.space = space,
+			.offset = offset,
+			.length = length,
+		},
+	};
+	struct cfg_read_pkg reply;
+	int retries = 0;
+
+	memcpy(&request.data, buffer, length * 4);
+
+	while (retries < TB_CTL_RETRIES) {
+		struct tb_cfg_request *req;
+
+		req = tb_cfg_request_alloc();
+		if (!req) {
+			res.err = -ENOMEM;
+			return res;
+		}
+
+		request.addr.seq = retries++;
+
+		req->match = tb_cfg_match;
+		req->copy = tb_cfg_copy;
+		req->request = &request;
+		req->request_size = 12 + 4 * length;
+		req->request_type = TB_CFG_PKG_WRITE;
+		req->response = &reply;
+		req->response_size = sizeof(reply);
+		req->response_type = TB_CFG_PKG_WRITE;
+
+		res = tb_cfg_request_sync(ctl, req, timeout_msec);
+
+		tb_cfg_request_put(req);
+
+		if (res.err != -ETIMEDOUT)
+			break;
+
+		/* Wait a bit (arbitrary time) until we send a retry */
+		usleep_range(10, 100);
+	}
+
+	if (res.err)
+		return res;
+
+	res.response_port = reply.addr.port;
+	res.err = check_config_address(reply.addr, space, offset, length);
+	return res;
+}
+
+static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
+			    const struct tb_cfg_result *res)
+{
+	/*
+	 * For unimplemented ports access to port config space may return
+	 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
+	 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
+	 * that the caller can mark the port as disabled.
+	 */
+	if (space == TB_CFG_PORT &&
+	    res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
+		return -ENODEV;
+
+	tb_cfg_print_error(ctl, space, res);
+
+	if (res->tb_error == TB_CFG_ERROR_LOCK)
+		return -EACCES;
+	if (res->tb_error == TB_CFG_ERROR_PORT_NOT_CONNECTED)
+		return -ENOTCONN;
+
+	return -EIO;
+}
+
+int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
+		enum tb_cfg_space space, u32 offset, u32 length)
+{
+	struct tb_cfg_result res = tb_cfg_read_raw(ctl, buffer, route, port,
+			space, offset, length, ctl->timeout_msec);
+	switch (res.err) {
+	case 0:
+		/* Success */
+		break;
+
+	case 1:
+		/* Thunderbolt error, tb_error holds the actual number */
+		return tb_cfg_get_error(ctl, space, &res);
+
+	case -ETIMEDOUT:
+		tb_ctl_warn(ctl, "%llx: timeout reading config space %u from %#x\n",
+			    route, space, offset);
+		break;
+
+	default:
+		WARN(1, "tb_cfg_read: %d\n", res.err);
+		break;
+	}
+	return res.err;
+}
+
+int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
+		 enum tb_cfg_space space, u32 offset, u32 length)
+{
+	struct tb_cfg_result res = tb_cfg_write_raw(ctl, buffer, route, port,
+			space, offset, length, ctl->timeout_msec);
+	switch (res.err) {
+	case 0:
+		/* Success */
+		break;
+
+	case 1:
+		/* Thunderbolt error, tb_error holds the actual number */
+		return tb_cfg_get_error(ctl, space, &res);
+
+	case -ETIMEDOUT:
+		tb_ctl_warn(ctl, "%llx: timeout writing config space %u to %#x\n",
+			    route, space, offset);
+		break;
+
+	default:
+		WARN(1, "tb_cfg_write: %d\n", res.err);
+		break;
+	}
+	return res.err;
+}
+
+/**
+ * tb_cfg_get_upstream_port() - get upstream port number of switch at route
+ * @ctl: Pointer to the control channel
+ * @route: Route string of the router
+ *
+ * Reads the first dword from the switches TB_CFG_SWITCH config area and
+ * returns the port number from which the reply originated.
+ *
+ * Return: Upstream port number on success or negative error code on failure.
+ */
+int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route)
+{
+	u32 dummy;
+	struct tb_cfg_result res = tb_cfg_read_raw(ctl, &dummy, route, 0,
+						   TB_CFG_SWITCH, 0, 1,
+						   ctl->timeout_msec);
+	if (res.err == 1)
+		return -EIO;
+	if (res.err)
+		return res.err;
+	return res.response_port;
+}