Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

6 files changed, 560 insertions, 0 deletions

diff --git a/Documentation/driver-api/mei/hdcp.rst b/Documentation/driver-api/mei/hdcp.rst
new file mode 100644
index 000000000..e85a065b1
--- /dev/null
+++ b/Documentation/driver-api/mei/hdcp.rst
@@ -0,0 +1,32 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+HDCP:
+=====
+
+ME FW as a security engine provides the capability for setting up
+HDCP2.2 protocol negotiation between the Intel graphics device and
+an HDC2.2 sink.
+
+ME FW prepares HDCP2.2 negotiation parameters, signs and encrypts them
+according the HDCP 2.2 spec. The Intel graphics sends the created blob
+to the HDCP2.2 sink.
+
+Similarly, the HDCP2.2 sink's response is transferred to ME FW
+for decryption and verification.
+
+Once all the steps of HDCP2.2 negotiation are completed,
+upon request ME FW will configure the port as authenticated and supply
+the HDCP encryption keys to Intel graphics hardware.
+
+
+mei_hdcp driver
+---------------
+.. kernel-doc:: drivers/misc/mei/hdcp/mei_hdcp.c
+    :doc: MEI_HDCP Client Driver
+
+mei_hdcp api
+------------
+
+.. kernel-doc:: drivers/misc/mei/hdcp/mei_hdcp.c
+    :functions:
+
diff --git a/Documentation/driver-api/mei/iamt.rst b/Documentation/driver-api/mei/iamt.rst
new file mode 100644
index 000000000..6ef3e6136
--- /dev/null
+++ b/Documentation/driver-api/mei/iamt.rst
@@ -0,0 +1,101 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Intel(R) Active Management Technology (Intel AMT)
+=================================================
+
+Prominent usage of the Intel ME Interface is to communicate with Intel(R)
+Active Management Technology (Intel AMT) implemented in firmware running on
+the Intel ME.
+
+Intel AMT provides the ability to manage a host remotely out-of-band (OOB)
+even when the operating system running on the host processor has crashed or
+is in a sleep state.
+
+Some examples of Intel AMT usage are:
+   - Monitoring hardware state and platform components
+   - Remote power off/on (useful for green computing or overnight IT
+     maintenance)
+   - OS updates
+   - Storage of useful platform information such as software assets
+   - Built-in hardware KVM
+   - Selective network isolation of Ethernet and IP protocol flows based
+     on policies set by a remote management console
+   - IDE device redirection from remote management console
+
+Intel AMT (OOB) communication is based on SOAP (deprecated
+starting with Release 6.0) over HTTP/S or WS-Management protocol over
+HTTP/S that are received from a remote management console application.
+
+For more information about Intel AMT:
+https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+
+
+Intel AMT Applications
+----------------------
+
+    1) Intel Local Management Service (Intel LMS)
+
+       Applications running locally on the platform communicate with Intel AMT Release
+       2.0 and later releases in the same way that network applications do via SOAP
+       over HTTP (deprecated starting with Release 6.0) or with WS-Management over
+       SOAP over HTTP. This means that some Intel AMT features can be accessed from a
+       local application using the same network interface as a remote application
+       communicating with Intel AMT over the network.
+
+       When a local application sends a message addressed to the local Intel AMT host
+       name, the Intel LMS, which listens for traffic directed to the host name,
+       intercepts the message and routes it to the Intel MEI.
+       For more information:
+       https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+       Under "About Intel AMT" => "Local Access"
+
+       For downloading Intel LMS:
+       https://github.com/intel/lms
+
+       The Intel LMS opens a connection using the Intel MEI driver to the Intel LMS
+       firmware feature using a defined GUID and then communicates with the feature
+       using a protocol called Intel AMT Port Forwarding Protocol (Intel APF protocol).
+       The protocol is used to maintain multiple sessions with Intel AMT from a
+       single application.
+
+       See the protocol specification in the Intel AMT Software Development Kit (SDK)
+       https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+       Under "SDK Resources" => "Intel(R) vPro(TM) Gateway (MPS)"
+       => "Information for Intel(R) vPro(TM) Gateway Developers"
+       => "Description of the Intel AMT Port Forwarding (APF) Protocol"
+
+    2) Intel AMT Remote configuration using a Local Agent
+
+       A Local Agent enables IT personnel to configure Intel AMT out-of-the-box
+       without requiring installing additional data to enable setup. The remote
+       configuration process may involve an ISV-developed remote configuration
+       agent that runs on the host.
+       For more information:
+       https://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/default.htm
+       Under "Setup and Configuration of Intel AMT" =>
+       "SDK Tools Supporting Setup and Configuration" =>
+       "Using the Local Agent Sample"
+
+Intel AMT OS Health Watchdog
+----------------------------
+
+The Intel AMT Watchdog is an OS Health (Hang/Crash) watchdog.
+Whenever the OS hangs or crashes, Intel AMT will send an event
+to any subscriber to this event. This mechanism means that
+IT knows when a platform crashes even when there is a hard failure on the host.
+
+The Intel AMT Watchdog is composed of two parts:
+    1) Firmware feature - receives the heartbeats
+       and sends an event when the heartbeats stop.
+    2) Intel MEI iAMT watchdog driver - connects to the watchdog feature,
+       configures the watchdog and sends the heartbeats.
+
+The Intel iAMT watchdog MEI driver uses the kernel watchdog API to configure
+the Intel AMT Watchdog and to send heartbeats to it. The default timeout of the
+watchdog is 120 seconds.
+
+If the Intel AMT is not enabled in the firmware then the watchdog client won't enumerate
+on the me client bus and watchdog devices won't be exposed.
+
+---
+linux-mei@linux.intel.com
diff --git a/Documentation/driver-api/mei/index.rst b/Documentation/driver-api/mei/index.rst
new file mode 100644
index 000000000..eae6f18f1
--- /dev/null
+++ b/Documentation/driver-api/mei/index.rst
@@ -0,0 +1,18 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. include:: <isonum.txt>
+
+===================================================
+Intel(R) Management Engine Interface (Intel(R) MEI)
+===================================================
+
+**Copyright** |copy| 2019 Intel Corporation
+
+
+.. toctree::
+   :caption: Table of Contents
+   :maxdepth: 3
+
+   mei
+   mei-client-bus
+   iamt
diff --git a/Documentation/driver-api/mei/mei-client-bus.rst b/Documentation/driver-api/mei/mei-client-bus.rst
new file mode 100644
index 000000000..f242b3f8d
--- /dev/null
+++ b/Documentation/driver-api/mei/mei-client-bus.rst
@@ -0,0 +1,168 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==============================================
+Intel(R) Management Engine (ME) Client bus API
+==============================================
+
+
+Rationale
+=========
+
+The MEI character device is useful for dedicated applications to send and receive
+data to the many FW appliance found in Intel's ME from the user space.
+However, for some of the ME functionalities it makes sense to leverage existing software
+stack and expose them through existing kernel subsystems.
+
+In order to plug seamlessly into the kernel device driver model we add kernel virtual
+bus abstraction on top of the MEI driver. This allows implementing Linux kernel drivers
+for the various MEI features as a stand alone entities found in their respective subsystem.
+Existing device drivers can even potentially be re-used by adding an MEI CL bus layer to
+the existing code.
+
+
+MEI CL bus API
+==============
+
+A driver implementation for an MEI Client is very similar to any other existing bus
+based device drivers. The driver registers itself as an MEI CL bus driver through
+the ``struct mei_cl_driver`` structure defined in :file:`include/linux/mei_cl_bus.c`
+
+.. code-block:: C
+
+        struct mei_cl_driver {
+                struct device_driver driver;
+                const char *name;
+
+                const struct mei_cl_device_id *id_table;
+
+                int (*probe)(struct mei_cl_device *dev, const struct mei_cl_id *id);
+                int (*remove)(struct mei_cl_device *dev);
+        };
+
+
+
+The mei_cl_device_id structure defined in :file:`include/linux/mod_devicetable.h` allows a
+driver to bind itself against a device name.
+
+.. code-block:: C
+
+        struct mei_cl_device_id {
+                char name[MEI_CL_NAME_SIZE];
+                uuid_le uuid;
+                __u8    version;
+                kernel_ulong_t driver_info;
+        };
+
+To actually register a driver on the ME Client bus one must call the :c:func:`mei_cl_add_driver`
+API. This is typically called at module initialization time.
+
+Once the driver is registered and bound to the device, a driver will typically
+try to do some I/O on this bus and this should be done through the :c:func:`mei_cl_send`
+and :c:func:`mei_cl_recv` functions. More detailed information is in :ref:`api` section.
+
+In order for a driver to be notified about pending traffic or event, the driver
+should register a callback via :c:func:`mei_cl_devev_register_rx_cb` and
+:c:func:`mei_cldev_register_notify_cb` function respectively.
+
+.. _api:
+
+API:
+----
+.. kernel-doc:: drivers/misc/mei/bus.c
+    :export: drivers/misc/mei/bus.c
+
+
+
+Example
+=======
+
+As a theoretical example let's pretend the ME comes with a "contact" NFC IP.
+The driver init and exit routines for this device would look like:
+
+.. code-block:: C
+
+        #define CONTACT_DRIVER_NAME "contact"
+
+        static struct mei_cl_device_id contact_mei_cl_tbl[] = {
+                { CONTACT_DRIVER_NAME, },
+
+                /* required last entry */
+                { }
+        };
+        MODULE_DEVICE_TABLE(mei_cl, contact_mei_cl_tbl);
+
+        static struct mei_cl_driver contact_driver = {
+                .id_table = contact_mei_tbl,
+                .name = CONTACT_DRIVER_NAME,
+
+                .probe = contact_probe,
+                .remove = contact_remove,
+        };
+
+        static int contact_init(void)
+        {
+                int r;
+
+                r = mei_cl_driver_register(&contact_driver);
+                if (r) {
+                        pr_err(CONTACT_DRIVER_NAME ": driver registration failed\n");
+                        return r;
+                }
+
+                return 0;
+        }
+
+        static void __exit contact_exit(void)
+        {
+                mei_cl_driver_unregister(&contact_driver);
+        }
+
+        module_init(contact_init);
+        module_exit(contact_exit);
+
+And the driver's simplified probe routine would look like that:
+
+.. code-block:: C
+
+        int contact_probe(struct mei_cl_device *dev, struct mei_cl_device_id *id)
+        {
+                [...]
+                mei_cldev_enable(dev);
+
+                mei_cldev_register_rx_cb(dev, contact_rx_cb);
+
+                return 0;
+        }
+
+In the probe routine the driver first enable the MEI device and then registers
+an rx handler which is as close as it can get to registering a threaded IRQ handler.
+The handler implementation will typically call :c:func:`mei_cldev_recv` and then
+process received data.
+
+.. code-block:: C
+
+        #define MAX_PAYLOAD 128
+        #define HDR_SIZE 4
+        static void conntact_rx_cb(struct mei_cl_device *cldev)
+        {
+                struct contact *c = mei_cldev_get_drvdata(cldev);
+                unsigned char payload[MAX_PAYLOAD];
+                ssize_t payload_sz;
+
+                payload_sz = mei_cldev_recv(cldev, payload,  MAX_PAYLOAD)
+                if (reply_size < HDR_SIZE) {
+                        return;
+                }
+
+                c->process_rx(payload);
+
+        }
+
+MEI Client Bus Drivers
+======================
+
+.. toctree::
+   :maxdepth: 2
+
+   hdcp
+   nfc
diff --git a/Documentation/driver-api/mei/mei.rst b/Documentation/driver-api/mei/mei.rst
new file mode 100644
index 000000000..4f2ced4cc
--- /dev/null
+++ b/Documentation/driver-api/mei/mei.rst
@@ -0,0 +1,213 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Introduction
+============
+
+The Intel Management Engine (Intel ME) is an isolated and protected computing
+resource (Co-processor) residing inside certain Intel chipsets. The Intel ME
+provides support for computer/IT management and security features.
+The actual feature set depends on the Intel chipset SKU.
+
+The Intel Management Engine Interface (Intel MEI, previously known as HECI)
+is the interface between the Host and Intel ME. This interface is exposed
+to the host as a PCI device, actually multiple PCI devices might be exposed.
+The Intel MEI Driver is in charge of the communication channel between
+a host application and the Intel ME features.
+
+Each Intel ME feature, or Intel ME Client is addressed by a unique GUID and
+each client has its own protocol. The protocol is message-based with a
+header and payload up to maximal number of bytes advertised by the client,
+upon connection.
+
+Intel MEI Driver
+================
+
+The driver exposes a character device with device nodes /dev/meiX.
+
+An application maintains communication with an Intel ME feature while
+/dev/meiX is open. The binding to a specific feature is performed by calling
+:c:macro:`MEI_CONNECT_CLIENT_IOCTL`, which passes the desired GUID.
+The number of instances of an Intel ME feature that can be opened
+at the same time depends on the Intel ME feature, but most of the
+features allow only a single instance.
+
+The driver is transparent to data that are passed between firmware feature
+and host application.
+
+Because some of the Intel ME features can change the system
+configuration, the driver by default allows only a privileged
+user to access it.
+
+The session is terminated calling :c:expr:`close(fd)`.
+
+A code snippet for an application communicating with Intel AMTHI client:
+
+In order to support virtualization or sandboxing a trusted supervisor
+can use :c:macro:`MEI_CONNECT_CLIENT_IOCTL_VTAG` to create
+virtual channels with an Intel ME feature. Not all features support
+virtual channels such client with answer EOPNOTSUPP.
+
+.. code-block:: C
+
+	struct mei_connect_client_data data;
+	fd = open(MEI_DEVICE);
+
+	data.d.in_client_uuid = AMTHI_GUID;
+
+	ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data);
+
+	printf("Ver=%d, MaxLen=%ld\n",
+	       data.d.in_client_uuid.protocol_version,
+	       data.d.in_client_uuid.max_msg_length);
+
+	[...]
+
+	write(fd, amthi_req_data, amthi_req_data_len);
+
+	[...]
+
+	read(fd, &amthi_res_data, amthi_res_data_len);
+
+	[...]
+	close(fd);
+
+
+User space API
+
+IOCTLs:
+=======
+
+The Intel MEI Driver supports the following IOCTL commands:
+
+IOCTL_MEI_CONNECT_CLIENT
+-------------------------
+Connect to firmware Feature/Client.
+
+.. code-block:: none
+
+	Usage:
+
+        struct mei_connect_client_data client_data;
+
+        ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &client_data);
+
+	Inputs:
+
+        struct mei_connect_client_data - contain the following
+	Input field:
+
+		in_client_uuid -	GUID of the FW Feature that needs
+					to connect to.
+         Outputs:
+		out_client_properties - Client Properties: MTU and Protocol Version.
+
+         Error returns:
+
+                ENOTTY  No such client (i.e. wrong GUID) or connection is not allowed.
+		EINVAL	Wrong IOCTL Number
+		ENODEV	Device or Connection is not initialized or ready.
+		ENOMEM	Unable to allocate memory to client internal data.
+		EFAULT	Fatal Error (e.g. Unable to access user input data)
+		EBUSY	Connection Already Open
+
+:Note:
+        max_msg_length (MTU) in client properties describes the maximum
+        data that can be sent or received. (e.g. if MTU=2K, can send
+        requests up to bytes 2k and received responses up to 2k bytes).
+
+IOCTL_MEI_CONNECT_CLIENT_VTAG:
+------------------------------
+
+.. code-block:: none
+
+        Usage:
+
+        struct mei_connect_client_data_vtag client_data_vtag;
+
+        ioctl(fd, IOCTL_MEI_CONNECT_CLIENT_VTAG, &client_data_vtag);
+
+        Inputs:
+
+        struct mei_connect_client_data_vtag - contain the following
+        Input field:
+
+                in_client_uuid -  GUID of the FW Feature that needs
+                                  to connect to.
+                vtag - virtual tag [1, 255]
+
+         Outputs:
+                out_client_properties - Client Properties: MTU and Protocol Version.
+
+         Error returns:
+
+                ENOTTY No such client (i.e. wrong GUID) or connection is not allowed.
+                EINVAL Wrong IOCTL Number or tag == 0
+                ENODEV Device or Connection is not initialized or ready.
+                ENOMEM Unable to allocate memory to client internal data.
+                EFAULT Fatal Error (e.g. Unable to access user input data)
+                EBUSY  Connection Already Open
+                EOPNOTSUPP Vtag is not supported
+
+IOCTL_MEI_NOTIFY_SET
+---------------------
+Enable or disable event notifications.
+
+
+.. code-block:: none
+
+	Usage:
+
+		uint32_t enable;
+
+		ioctl(fd, IOCTL_MEI_NOTIFY_SET, &enable);
+
+
+		uint32_t enable = 1;
+		or
+		uint32_t enable[disable] = 0;
+
+	Error returns:
+
+
+		EINVAL	Wrong IOCTL Number
+		ENODEV	Device  is not initialized or the client not connected
+		ENOMEM	Unable to allocate memory to client internal data.
+		EFAULT	Fatal Error (e.g. Unable to access user input data)
+		EOPNOTSUPP if the device doesn't support the feature
+
+:Note:
+	The client must be connected in order to enable notification events
+
+
+IOCTL_MEI_NOTIFY_GET
+--------------------
+Retrieve event
+
+.. code-block:: none
+
+	Usage:
+		uint32_t event;
+		ioctl(fd, IOCTL_MEI_NOTIFY_GET, &event);
+
+	Outputs:
+		1 - if an event is pending
+		0 - if there is no even pending
+
+	Error returns:
+		EINVAL	Wrong IOCTL Number
+		ENODEV	Device is not initialized or the client not connected
+		ENOMEM	Unable to allocate memory to client internal data.
+		EFAULT	Fatal Error (e.g. Unable to access user input data)
+		EOPNOTSUPP if the device doesn't support the feature
+
+:Note:
+	The client must be connected and event notification has to be enabled
+	in order to receive an event
+
+
+
+Supported Chipsets
+==================
+82X38/X48 Express and newer
+
+linux-mei@linux.intel.com
diff --git a/Documentation/driver-api/mei/nfc.rst b/Documentation/driver-api/mei/nfc.rst
new file mode 100644
index 000000000..8fe8664c2
--- /dev/null
+++ b/Documentation/driver-api/mei/nfc.rst
@@ -0,0 +1,28 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+MEI NFC
+-------
+
+Some Intel 8 and 9 Series chipsets support NFC devices connected behind
+the Intel Management Engine controller.
+MEI client bus exposes the NFC chips as NFC phy devices and enables
+binding with Microread and NXP PN544 NFC device driver from the Linux NFC
+subsystem.
+
+.. kernel-render:: DOT
+   :alt: MEI NFC digraph
+   :caption: **MEI NFC** Stack
+
+   digraph NFC {
+    cl_nfc -> me_cl_nfc;
+    "drivers/nfc/mei_phy" -> cl_nfc [lhead=bus];
+    "drivers/nfc/microread/mei" -> cl_nfc;
+    "drivers/nfc/microread/mei" -> "drivers/nfc/mei_phy";
+    "drivers/nfc/pn544/mei" -> cl_nfc;
+    "drivers/nfc/pn544/mei" -> "drivers/nfc/mei_phy";
+    "net/nfc" -> "drivers/nfc/microread/mei";
+    "net/nfc" -> "drivers/nfc/pn544/mei";
+    "neard" -> "net/nfc";
+    cl_nfc [label="mei/bus(nfc)"];
+    me_cl_nfc [label="me fw (nfc)"];
+   }