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, 233 insertions, 0 deletions

diff --git a/Documentation/input/gameport-programming.rst b/Documentation/input/gameport-programming.rst
new file mode 100644
index 000000000..7d7063ad0
--- /dev/null
+++ b/Documentation/input/gameport-programming.rst
@@ -0,0 +1,233 @@
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Programming gameport drivers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A basic classic gameport
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+If the gameport doesn't provide more than the inb()/outb() functionality,
+the code needed to register it with the joystick drivers is simple::
+
+	struct gameport gameport;
+
+	gameport.io = MY_IO_ADDRESS;
+	gameport_register_port(&gameport);
+
+Make sure struct gameport is initialized to 0 in all other fields. The
+gameport generic code will take care of the rest.
+
+If your hardware supports more than one io address, and your driver can
+choose which one to program the hardware to, starting from the more exotic
+addresses is preferred, because the likelihood of clashing with the standard
+0x201 address is smaller.
+
+E.g. if your driver supports addresses 0x200, 0x208, 0x210 and 0x218, then
+0x218 would be the address of first choice.
+
+If your hardware supports a gameport address that is not mapped to ISA io
+space (is above 0x1000), use that one, and don't map the ISA mirror.
+
+Also, always request_region() on the whole io space occupied by the
+gameport. Although only one ioport is really used, the gameport usually
+occupies from one to sixteen addresses in the io space.
+
+Please also consider enabling the gameport on the card in the ->open()
+callback if the io is mapped to ISA space - this way it'll occupy the io
+space only when something really is using it. Disable it again in the
+->close() callback. You also can select the io address in the ->open()
+callback, so that it doesn't fail if some of the possible addresses are
+already occupied by other gameports.
+
+Memory mapped gameport
+~~~~~~~~~~~~~~~~~~~~~~
+
+When a gameport can be accessed through MMIO, this way is preferred, because
+it is faster, allowing more reads per second. Registering such a gameport
+isn't as easy as a basic IO one, but not so much complex::
+
+	struct gameport gameport;
+
+	void my_trigger(struct gameport *gameport)
+	{
+		my_mmio = 0xff;
+	}
+
+	unsigned char my_read(struct gameport *gameport)
+	{
+		return my_mmio;
+	}
+
+	gameport.read = my_read;
+	gameport.trigger = my_trigger;
+	gameport_register_port(&gameport);
+
+.. _gameport_pgm_cooked_mode:
+
+Cooked mode gameport
+~~~~~~~~~~~~~~~~~~~~
+
+There are gameports that can report the axis values as numbers, that means
+the driver doesn't have to measure them the old way - an ADC is built into
+the gameport. To register a cooked gameport::
+
+	struct gameport gameport;
+
+	int my_cooked_read(struct gameport *gameport, int *axes, int *buttons)
+	{
+		int i;
+
+		for (i = 0; i < 4; i++)
+			axes[i] = my_mmio[i];
+		buttons[0] = my_mmio[4];
+	}
+
+	int my_open(struct gameport *gameport, int mode)
+	{
+		return -(mode != GAMEPORT_MODE_COOKED);
+	}
+
+	gameport.cooked_read = my_cooked_read;
+	gameport.open = my_open;
+	gameport.fuzz = 8;
+	gameport_register_port(&gameport);
+
+The only confusing thing here is the fuzz value. Best determined by
+experimentation, it is the amount of noise in the ADC data. Perfect
+gameports can set this to zero, most common have fuzz between 8 and 32.
+See analog.c and input.c for handling of fuzz - the fuzz value determines
+the size of a gaussian filter window that is used to eliminate the noise
+in the data.
+
+More complex gameports
+~~~~~~~~~~~~~~~~~~~~~~
+
+Gameports can support both raw and cooked modes. In that case combine either
+examples 1+2 or 1+3. Gameports can support internal calibration - see below,
+and also lightning.c and analog.c on how that works. If your driver supports
+more than one gameport instance simultaneously, use the ->private member of
+the gameport struct to point to your data.
+
+Unregistering a gameport
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Simple::
+
+    gameport_unregister_port(&gameport);
+
+The gameport structure
+~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    struct gameport {
+
+	void *port_data;
+
+A private pointer for free use in the gameport driver. (Not the joystick
+driver!)
+
+::
+
+	char name[32];
+
+Driver's name as set by driver calling gameport_set_name(). Informational
+purpose only.
+
+::
+
+	char phys[32];
+
+gameport's physical name/description as set by driver calling gameport_set_phys().
+Informational purpose only.
+
+::
+
+	int io;
+
+I/O address for use with raw mode. You have to either set this, or ->read()
+to some value if your gameport supports raw mode.
+
+::
+
+	int speed;
+
+Raw mode speed of the gameport reads in thousands of reads per second.
+
+::
+
+	int fuzz;
+
+If the gameport supports cooked mode, this should be set to a value that
+represents the amount of noise in the data. See
+:ref:`gameport_pgm_cooked_mode`.
+
+::
+
+	void (*trigger)(struct gameport *);
+
+Trigger. This function should trigger the ns558 oneshots. If set to NULL,
+outb(0xff, io) will be used.
+
+::
+
+	unsigned char (*read)(struct gameport *);
+
+Read the buttons and ns558 oneshot bits. If set to NULL, inb(io) will be
+used instead.
+
+::
+
+	int (*cooked_read)(struct gameport *, int *axes, int *buttons);
+
+If the gameport supports cooked mode, it should point this to its cooked
+read function. It should fill axes[0..3] with four values of the joystick axes
+and buttons[0] with four bits representing the buttons.
+
+::
+
+	int (*calibrate)(struct gameport *, int *axes, int *max);
+
+Function for calibrating the ADC hardware. When called, axes[0..3] should be
+pre-filled by cooked data by the caller, max[0..3] should be pre-filled with
+expected maximums for each axis. The calibrate() function should set the
+sensitivity of the ADC hardware so that the maximums fit in its range and
+recompute the axes[] values to match the new sensitivity or re-read them from
+the hardware so that they give valid values.
+
+::
+
+	int (*open)(struct gameport *, int mode);
+
+Open() serves two purposes. First a driver either opens the port in raw or
+in cooked mode, the open() callback can decide which modes are supported.
+Second, resource allocation can happen here. The port can also be enabled
+here. Prior to this call, other fields of the gameport struct (namely the io
+member) need not to be valid.
+
+::
+
+	void (*close)(struct gameport *);
+
+Close() should free the resources allocated by open, possibly disabling the
+gameport.
+
+::
+
+	struct timer_list poll_timer;
+	unsigned int poll_interval;     /* in msecs */
+	spinlock_t timer_lock;
+	unsigned int poll_cnt;
+	void (*poll_handler)(struct gameport *);
+	struct gameport *parent, *child;
+	struct gameport_driver *drv;
+	struct mutex drv_mutex;		/* protects serio->drv so attributes can pin driver */
+	struct device dev;
+	struct list_head node;
+
+For internal use by the gameport layer.
+
+::
+
+    };
+
+Enjoy!