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
  ...

3 files changed, 370 insertions, 0 deletions

diff --git a/Documentation/driver-api/phy/index.rst b/Documentation/driver-api/phy/index.rst
new file mode 100644
index 000000000..579cfe3b7
--- /dev/null
+++ b/Documentation/driver-api/phy/index.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=====================
+Generic PHY Framework
+=====================
+
+.. toctree::
+
+   phy
+   samsung-usb2
diff --git a/Documentation/driver-api/phy/phy.rst b/Documentation/driver-api/phy/phy.rst
new file mode 100644
index 000000000..0865c2e94
--- /dev/null
+++ b/Documentation/driver-api/phy/phy.rst
@@ -0,0 +1,223 @@
+=============
+PHY subsystem
+=============
+
+:Author: Kishon Vijay Abraham I <kishon@ti.com>
+
+This document explains the Generic PHY Framework along with the APIs provided,
+and how-to-use.
+
+Introduction
+============
+
+*PHY* is the abbreviation for physical layer. It is used to connect a device
+to the physical medium e.g., the USB controller has a PHY to provide functions
+such as serialization, de-serialization, encoding, decoding and is responsible
+for obtaining the required data transmission rate. Note that some USB
+controllers have PHY functionality embedded into it and others use an external
+PHY. Other peripherals that use PHY include Wireless LAN, Ethernet,
+SATA etc.
+
+The intention of creating this framework is to bring the PHY drivers spread
+all over the Linux kernel to drivers/phy to increase code reuse and for
+better code maintainability.
+
+This framework will be of use only to devices that use external PHY (PHY
+functionality is not embedded within the controller).
+
+Registering/Unregistering the PHY provider
+==========================================
+
+PHY provider refers to an entity that implements one or more PHY instances.
+For the simple case where the PHY provider implements only a single instance of
+the PHY, the framework provides its own implementation of of_xlate in
+of_phy_simple_xlate. If the PHY provider implements multiple instances, it
+should provide its own implementation of of_xlate. of_xlate is used only for
+dt boot case.
+
+::
+
+	#define of_phy_provider_register(dev, xlate)    \
+		__of_phy_provider_register((dev), NULL, THIS_MODULE, (xlate))
+
+	#define devm_of_phy_provider_register(dev, xlate)       \
+		__devm_of_phy_provider_register((dev), NULL, THIS_MODULE,
+						(xlate))
+
+of_phy_provider_register and devm_of_phy_provider_register macros can be used to
+register the phy_provider and it takes device and of_xlate as
+arguments. For the dt boot case, all PHY providers should use one of the above
+2 macros to register the PHY provider.
+
+Often the device tree nodes associated with a PHY provider will contain a set
+of children that each represent a single PHY. Some bindings may nest the child
+nodes within extra levels for context and extensibility, in which case the low
+level of_phy_provider_register_full() and devm_of_phy_provider_register_full()
+macros can be used to override the node containing the children.
+
+::
+
+	#define of_phy_provider_register_full(dev, children, xlate) \
+		__of_phy_provider_register(dev, children, THIS_MODULE, xlate)
+
+	#define devm_of_phy_provider_register_full(dev, children, xlate) \
+		__devm_of_phy_provider_register_full(dev, children,
+						     THIS_MODULE, xlate)
+
+	void devm_of_phy_provider_unregister(struct device *dev,
+		struct phy_provider *phy_provider);
+	void of_phy_provider_unregister(struct phy_provider *phy_provider);
+
+devm_of_phy_provider_unregister and of_phy_provider_unregister can be used to
+unregister the PHY.
+
+Creating the PHY
+================
+
+The PHY driver should create the PHY in order for other peripheral controllers
+to make use of it. The PHY framework provides 2 APIs to create the PHY.
+
+::
+
+	struct phy *phy_create(struct device *dev, struct device_node *node,
+			       const struct phy_ops *ops);
+	struct phy *devm_phy_create(struct device *dev,
+				    struct device_node *node,
+				    const struct phy_ops *ops);
+
+The PHY drivers can use one of the above 2 APIs to create the PHY by passing
+the device pointer and phy ops.
+phy_ops is a set of function pointers for performing PHY operations such as
+init, exit, power_on and power_off.
+
+Inorder to dereference the private data (in phy_ops), the phy provider driver
+can use phy_set_drvdata() after creating the PHY and use phy_get_drvdata() in
+phy_ops to get back the private data.
+
+Getting a reference to the PHY
+==============================
+
+Before the controller can make use of the PHY, it has to get a reference to
+it. This framework provides the following APIs to get a reference to the PHY.
+
+::
+
+	struct phy *phy_get(struct device *dev, const char *string);
+	struct phy *devm_phy_get(struct device *dev, const char *string);
+	struct phy *devm_phy_optional_get(struct device *dev,
+					  const char *string);
+	struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
+				    const char *con_id);
+	struct phy *devm_of_phy_optional_get(struct device *dev,
+					     struct device_node *np,
+					     const char *con_id);
+	struct phy *devm_of_phy_get_by_index(struct device *dev,
+					     struct device_node *np,
+					     int index);
+
+phy_get, devm_phy_get and devm_phy_optional_get can be used to get the PHY.
+In the case of dt boot, the string arguments
+should contain the phy name as given in the dt data and in the case of
+non-dt boot, it should contain the label of the PHY.  The two
+devm_phy_get associates the device with the PHY using devres on
+successful PHY get. On driver detach, release function is invoked on
+the devres data and devres data is freed.
+The _optional_get variants should be used when the phy is optional. These
+functions will never return -ENODEV, but instead return NULL when
+the phy cannot be found.
+Some generic drivers, such as ehci, may use multiple phys. In this case,
+devm_of_phy_get or devm_of_phy_get_by_index can be used to get a phy
+reference based on name or index.
+
+It should be noted that NULL is a valid phy reference. All phy
+consumer calls on the NULL phy become NOPs. That is the release calls,
+the phy_init() and phy_exit() calls, and phy_power_on() and
+phy_power_off() calls are all NOP when applied to a NULL phy. The NULL
+phy is useful in devices for handling optional phy devices.
+
+Order of API calls
+==================
+
+The general order of calls should be::
+
+    [devm_][of_]phy_get()
+    phy_init()
+    phy_power_on()
+    [phy_set_mode[_ext]()]
+    ...
+    phy_power_off()
+    phy_exit()
+    [[of_]phy_put()]
+
+Some PHY drivers may not implement :c:func:`phy_init` or :c:func:`phy_power_on`,
+but controllers should always call these functions to be compatible with other
+PHYs. Some PHYs may require :c:func:`phy_set_mode <phy_set_mode_ext>`, while
+others may use a default mode (typically configured via devicetree or other
+firmware). For compatibility, you should always call this function if you know
+what mode you will be using. Generally, this function should be called after
+:c:func:`phy_power_on`, although some PHY drivers may allow it at any time.
+
+Releasing a reference to the PHY
+================================
+
+When the controller no longer needs the PHY, it has to release the reference
+to the PHY it has obtained using the APIs mentioned in the above section. The
+PHY framework provides 2 APIs to release a reference to the PHY.
+
+::
+
+	void phy_put(struct phy *phy);
+	void devm_phy_put(struct device *dev, struct phy *phy);
+
+Both these APIs are used to release a reference to the PHY and devm_phy_put
+destroys the devres associated with this PHY.
+
+Destroying the PHY
+==================
+
+When the driver that created the PHY is unloaded, it should destroy the PHY it
+created using one of the following 2 APIs::
+
+	void phy_destroy(struct phy *phy);
+	void devm_phy_destroy(struct device *dev, struct phy *phy);
+
+Both these APIs destroy the PHY and devm_phy_destroy destroys the devres
+associated with this PHY.
+
+PM Runtime
+==========
+
+This subsystem is pm runtime enabled. So while creating the PHY,
+pm_runtime_enable of the phy device created by this subsystem is called and
+while destroying the PHY, pm_runtime_disable is called. Note that the phy
+device created by this subsystem will be a child of the device that calls
+phy_create (PHY provider device).
+
+So pm_runtime_get_sync of the phy_device created by this subsystem will invoke
+pm_runtime_get_sync of PHY provider device because of parent-child relationship.
+It should also be noted that phy_power_on and phy_power_off performs
+phy_pm_runtime_get_sync and phy_pm_runtime_put respectively.
+There are exported APIs like phy_pm_runtime_get, phy_pm_runtime_get_sync,
+phy_pm_runtime_put and phy_pm_runtime_put_sync for performing PM operations.
+
+PHY Mappings
+============
+
+In order to get reference to a PHY without help from DeviceTree, the framework
+offers lookups which can be compared to clkdev that allow clk structures to be
+bound to devices. A lookup can be made during runtime when a handle to the
+struct phy already exists.
+
+The framework offers the following API for registering and unregistering the
+lookups::
+
+	int phy_create_lookup(struct phy *phy, const char *con_id,
+			      const char *dev_id);
+	void phy_remove_lookup(struct phy *phy, const char *con_id,
+			       const char *dev_id);
+
+DeviceTree Binding
+==================
+
+The documentation for PHY dt binding can be found @
+Documentation/devicetree/bindings/phy/phy-bindings.txt
diff --git a/Documentation/driver-api/phy/samsung-usb2.rst b/Documentation/driver-api/phy/samsung-usb2.rst
new file mode 100644
index 000000000..c48c8b979
--- /dev/null
+++ b/Documentation/driver-api/phy/samsung-usb2.rst
@@ -0,0 +1,137 @@
+====================================
+Samsung USB 2.0 PHY adaptation layer
+====================================
+
+1. Description
+--------------
+
+The architecture of the USB 2.0 PHY module in Samsung SoCs is similar
+among many SoCs. In spite of the similarities it proved difficult to
+create a one driver that would fit all these PHY controllers. Often
+the differences were minor and were found in particular bits of the
+registers of the PHY. In some rare cases the order of register writes or
+the PHY powering up process had to be altered. This adaptation layer is
+a compromise between having separate drivers and having a single driver
+with added support for many special cases.
+
+2. Files description
+--------------------
+
+- phy-samsung-usb2.c
+   This is the main file of the adaptation layer. This file contains
+   the probe function and provides two callbacks to the Generic PHY
+   Framework. This two callbacks are used to power on and power off the
+   phy. They carry out the common work that has to be done on all version
+   of the PHY module. Depending on which SoC was chosen they execute SoC
+   specific callbacks. The specific SoC version is selected by choosing
+   the appropriate compatible string. In addition, this file contains
+   struct of_device_id definitions for particular SoCs.
+
+- phy-samsung-usb2.h
+   This is the include file. It declares the structures used by this
+   driver. In addition it should contain extern declarations for
+   structures that describe particular SoCs.
+
+3. Supporting SoCs
+------------------
+
+To support a new SoC a new file should be added to the drivers/phy
+directory. Each SoC's configuration is stored in an instance of the
+struct samsung_usb2_phy_config::
+
+  struct samsung_usb2_phy_config {
+	const struct samsung_usb2_common_phy *phys;
+	int (*rate_to_clk)(unsigned long, u32 *);
+	unsigned int num_phys;
+	bool has_mode_switch;
+  };
+
+The num_phys is the number of phys handled by the driver. `*phys` is an
+array that contains the configuration for each phy. The has_mode_switch
+property is a boolean flag that determines whether the SoC has USB host
+and device on a single pair of pins. If so, a special register has to
+be modified to change the internal routing of these pins between a USB
+device or host module.
+
+For example the configuration for Exynos 4210 is following::
+
+  const struct samsung_usb2_phy_config exynos4210_usb2_phy_config = {
+	.has_mode_switch        = 0,
+	.num_phys		= EXYNOS4210_NUM_PHYS,
+	.phys			= exynos4210_phys,
+	.rate_to_clk		= exynos4210_rate_to_clk,
+  }
+
+- `int (*rate_to_clk)(unsigned long, u32 *)`
+
+	The rate_to_clk callback is to convert the rate of the clock
+	used as the reference clock for the PHY module to the value
+	that should be written in the hardware register.
+
+The exynos4210_phys configuration array is as follows::
+
+  static const struct samsung_usb2_common_phy exynos4210_phys[] = {
+	{
+		.label		= "device",
+		.id		= EXYNOS4210_DEVICE,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "host",
+		.id		= EXYNOS4210_HOST,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "hsic0",
+		.id		= EXYNOS4210_HSIC0,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "hsic1",
+		.id		= EXYNOS4210_HSIC1,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{},
+  };
+
+- `int (*power_on)(struct samsung_usb2_phy_instance *);`
+  `int (*power_off)(struct samsung_usb2_phy_instance *);`
+
+	These two callbacks are used to power on and power off the phy
+	by modifying appropriate registers.
+
+Final change to the driver is adding appropriate compatible value to the
+phy-samsung-usb2.c file. In case of Exynos 4210 the following lines were
+added to the struct of_device_id samsung_usb2_phy_of_match[] array::
+
+  #ifdef CONFIG_PHY_EXYNOS4210_USB2
+	{
+		.compatible = "samsung,exynos4210-usb2-phy",
+		.data = &exynos4210_usb2_phy_config,
+	},
+  #endif
+
+To add further flexibility to the driver the Kconfig file enables to
+include support for selected SoCs in the compiled driver. The Kconfig
+entry for Exynos 4210 is following::
+
+  config PHY_EXYNOS4210_USB2
+	bool "Support for Exynos 4210"
+	depends on PHY_SAMSUNG_USB2
+	depends on CPU_EXYNOS4210
+	help
+	  Enable USB PHY support for Exynos 4210. This option requires that
+	  Samsung USB 2.0 PHY driver is enabled and means that support for this
+	  particular SoC is compiled in the driver. In case of Exynos 4210 four
+	  phys are available - device, host, HSCI0 and HSCI1.
+
+The newly created file that supports the new SoC has to be also added to the
+Makefile. In case of Exynos 4210 the added line is following::
+
+  obj-$(CONFIG_PHY_EXYNOS4210_USB2)       += phy-exynos4210-usb2.o
+
+After completing these steps the support for the new SoC should be ready.