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
  ...

14 files changed, 852 insertions, 0 deletions

diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst
new file mode 100644
index 000000000..bc1c961ba
--- /dev/null
+++ b/Documentation/driver-api/firmware/built-in-fw.rst
@@ -0,0 +1,33 @@
+=================
+Built-in firmware
+=================
+
+Firmware can be built-in to the kernel, this means building the firmware
+into vmlinux directly, to enable avoiding having to look for firmware from
+the filesystem. Instead, firmware can be looked for inside the kernel
+directly. You can enable built-in firmware using the kernel configuration
+options:
+
+  * CONFIG_EXTRA_FIRMWARE
+  * CONFIG_EXTRA_FIRMWARE_DIR
+
+There are a few reasons why you might want to consider building your firmware
+into the kernel with CONFIG_EXTRA_FIRMWARE:
+
+* Speed
+* Firmware is needed for accessing the boot device, and the user doesn't
+  want to stuff the firmware into the boot initramfs.
+
+Even if you have these needs there are a few reasons why you may not be
+able to make use of built-in firmware:
+
+* Legalese - firmware is non-GPL compatible
+* Some firmware may be optional
+* Firmware upgrades are possible, therefore a new firmware would implicate
+  a complete kernel rebuild.
+* Some firmware files may be really large in size. The remote-proc subsystem
+  is an example subsystem which deals with these sorts of firmware
+* The firmware may need to be scraped out from some device specific location
+  dynamically, an example is calibration data for some WiFi chipsets. This
+  calibration data can be unique per sold device.
+
diff --git a/Documentation/driver-api/firmware/core.rst b/Documentation/driver-api/firmware/core.rst
new file mode 100644
index 000000000..803cd574b
--- /dev/null
+++ b/Documentation/driver-api/firmware/core.rst
@@ -0,0 +1,17 @@
+==========================
+Firmware API core features
+==========================
+
+The firmware API has a rich set of core features available. This section
+documents these features.
+
+.. toctree::
+
+   fw_search_path
+   built-in-fw
+   firmware_cache
+   direct-fs-lookup
+   fallback-mechanisms
+   lookup-order
+   firmware-usage-guidelines
+
diff --git a/Documentation/driver-api/firmware/direct-fs-lookup.rst b/Documentation/driver-api/firmware/direct-fs-lookup.rst
new file mode 100644
index 000000000..e04353d1b
--- /dev/null
+++ b/Documentation/driver-api/firmware/direct-fs-lookup.rst
@@ -0,0 +1,30 @@
+========================
+Direct filesystem lookup
+========================
+
+Direct filesystem lookup is the most common form of firmware lookup performed
+by the kernel. The kernel looks for the firmware directly on the root
+filesystem in the paths documented in the section 'Firmware search paths'.
+The filesystem lookup is implemented in fw_get_filesystem_firmware(), it
+uses common core kernel file loader facility kernel_read_file_from_path().
+The max path allowed is PATH_MAX -- currently this is 4096 characters.
+
+It is recommended you keep /lib/firmware paths on your root filesystem,
+avoid having a separate partition for them in order to avoid possible
+races with lookups and avoid uses of the custom fallback mechanisms
+documented below.
+
+Firmware and initramfs
+----------------------
+
+Drivers which are built-in to the kernel should have the firmware integrated
+also as part of the initramfs used to boot the kernel given that otherwise
+a race is possible with loading the driver and the real rootfs not yet being
+available. Stuffing the firmware into initramfs resolves this race issue,
+however note that using initrd does not suffice to address the same race.
+
+There are circumstances that justify not wanting to include firmware into
+initramfs, such as dealing with large firmware files for the
+remote-proc subsystem. For such cases using a userspace fallback mechanism
+is currently the only viable solution as only userspace can know for sure
+when the real rootfs is ready and mounted.
diff --git a/Documentation/driver-api/firmware/efi/index.rst b/Documentation/driver-api/firmware/efi/index.rst
new file mode 100644
index 000000000..5a6b62295
--- /dev/null
+++ b/Documentation/driver-api/firmware/efi/index.rst
@@ -0,0 +1,16 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================================================
+Unified Extensible Firmware Interface (UEFI) Support
+====================================================
+
+UEFI stub library functions
+===========================
+
+.. kernel-doc:: drivers/firmware/efi/libstub/mem.c
+   :internal:
+
+UEFI Common Platform Error Record (CPER) functions
+==================================================
+
+.. kernel-doc:: drivers/firmware/efi/cper.c
diff --git a/Documentation/driver-api/firmware/fallback-mechanisms.rst b/Documentation/driver-api/firmware/fallback-mechanisms.rst
new file mode 100644
index 000000000..5f04c3bcd
--- /dev/null
+++ b/Documentation/driver-api/firmware/fallback-mechanisms.rst
@@ -0,0 +1,308 @@
+===================
+Fallback mechanisms
+===================
+
+A fallback mechanism is supported to allow to overcome failures to do a direct
+filesystem lookup on the root filesystem or when the firmware simply cannot be
+installed for practical reasons on the root filesystem. The kernel
+configuration options related to supporting the firmware fallback mechanism are:
+
+  * CONFIG_FW_LOADER_USER_HELPER: enables building the firmware fallback
+    mechanism. Most distributions enable this option today. If enabled but
+    CONFIG_FW_LOADER_USER_HELPER_FALLBACK is disabled, only the custom fallback
+    mechanism is available and for the request_firmware_nowait() call.
+  * CONFIG_FW_LOADER_USER_HELPER_FALLBACK: force enables each request to
+    enable the kobject uevent fallback mechanism on all firmware API calls
+    except request_firmware_direct(). Most distributions disable this option
+    today. The call request_firmware_nowait() allows for one alternative
+    fallback mechanism: if this kconfig option is enabled and your second
+    argument to request_firmware_nowait(), uevent, is set to false you are
+    informing the kernel that you have a custom fallback mechanism and it will
+    manually load the firmware. Read below for more details.
+
+Note that this means when having this configuration:
+
+CONFIG_FW_LOADER_USER_HELPER=y
+CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n
+
+the kobject uevent fallback mechanism will never take effect even
+for request_firmware_nowait() when uevent is set to true.
+
+Justifying the firmware fallback mechanism
+==========================================
+
+Direct filesystem lookups may fail for a variety of reasons. Known reasons for
+this are worth itemizing and documenting as it justifies the need for the
+fallback mechanism:
+
+* Race against access with the root filesystem upon bootup.
+
+* Races upon resume from suspend. This is resolved by the firmware cache, but
+  the firmware cache is only supported if you use uevents, and its not
+  supported for request_firmware_into_buf().
+
+* Firmware is not accessible through typical means:
+
+        * It cannot be installed into the root filesystem
+        * The firmware provides very unique device specific data tailored for
+          the unit gathered with local information. An example is calibration
+          data for WiFi chipsets for mobile devices. This calibration data is
+          not common to all units, but tailored per unit.  Such information may
+          be installed on a separate flash partition other than where the root
+          filesystem is provided.
+
+Types of fallback mechanisms
+============================
+
+There are really two fallback mechanisms available using one shared sysfs
+interface as a loading facility:
+
+* Kobject uevent fallback mechanism
+* Custom fallback mechanism
+
+First lets document the shared sysfs loading facility.
+
+Firmware sysfs loading facility
+===============================
+
+In order to help device drivers upload firmware using a fallback mechanism
+the firmware infrastructure creates a sysfs interface to enable userspace
+to load and indicate when firmware is ready. The sysfs directory is created
+via fw_create_instance(). This call creates a new struct device named after
+the firmware requested, and establishes it in the device hierarchy by
+associating the device used to make the request as the device's parent.
+The sysfs directory's file attributes are defined and controlled through
+the new device's class (firmware_class) and group (fw_dev_attr_groups).
+This is actually where the original firmware_class module name came from,
+given that originally the only firmware loading mechanism available was the
+mechanism we now use as a fallback mechanism, which registers a struct class
+firmware_class. Because the attributes exposed are part of the module name, the
+module name firmware_class cannot be renamed in the future, to ensure backward
+compatibility with old userspace.
+
+To load firmware using the sysfs interface we expose a loading indicator,
+and a file upload firmware into:
+
+  * /sys/$DEVPATH/loading
+  * /sys/$DEVPATH/data
+
+To upload firmware you will echo 1 onto the loading file to indicate
+you are loading firmware. You then write the firmware into the data file,
+and you notify the kernel the firmware is ready by echo'ing 0 onto
+the loading file.
+
+The firmware device used to help load firmware using sysfs is only created if
+direct firmware loading fails and if the fallback mechanism is enabled for your
+firmware request, this is set up with :c:func:`firmware_fallback_sysfs`. It is
+important to re-iterate that no device is created if a direct filesystem lookup
+succeeded.
+
+Using::
+
+        echo 1 > /sys/$DEVPATH/loading
+
+Will clean any previous partial load at once and make the firmware API
+return an error. When loading firmware the firmware_class grows a buffer
+for the firmware in PAGE_SIZE increments to hold the image as it comes in.
+
+firmware_data_read() and firmware_loading_show() are just provided for the
+test_firmware driver for testing, they are not called in normal use or
+expected to be used regularly by userspace.
+
+firmware_fallback_sysfs
+-----------------------
+.. kernel-doc:: drivers/base/firmware_loader/fallback.c
+   :functions: firmware_fallback_sysfs
+
+Firmware kobject uevent fallback mechanism
+==========================================
+
+Since a device is created for the sysfs interface to help load firmware as a
+fallback mechanism userspace can be informed of the addition of the device by
+relying on kobject uevents. The addition of the device into the device
+hierarchy means the fallback mechanism for firmware loading has been initiated.
+For details of implementation refer to fw_load_sysfs_fallback(), in particular
+on the use of dev_set_uevent_suppress() and kobject_uevent().
+
+The kernel's kobject uevent mechanism is implemented in lib/kobject_uevent.c,
+it issues uevents to userspace. As a supplement to kobject uevents Linux
+distributions could also enable CONFIG_UEVENT_HELPER_PATH, which makes use of
+core kernel's usermode helper (UMH) functionality to call out to a userspace
+helper for kobject uevents. In practice though no standard distribution has
+ever used the CONFIG_UEVENT_HELPER_PATH. If CONFIG_UEVENT_HELPER_PATH is
+enabled this binary would be called each time kobject_uevent_env() gets called
+in the kernel for each kobject uevent triggered.
+
+Different implementations have been supported in userspace to take advantage of
+this fallback mechanism. When firmware loading was only possible using the
+sysfs mechanism the userspace component "hotplug" provided the functionality of
+monitoring for kobject events. Historically this was superseded be systemd's
+udev, however firmware loading support was removed from udev as of systemd
+commit be2ea723b1d0 ("udev: remove userspace firmware loading support")
+as of v217 on August, 2014. This means most Linux distributions today are
+not using or taking advantage of the firmware fallback mechanism provided
+by kobject uevents. This is specially exacerbated due to the fact that most
+distributions today disable CONFIG_FW_LOADER_USER_HELPER_FALLBACK.
+
+Refer to do_firmware_uevent() for details of the kobject event variables
+setup. The variables currently passed to userspace with a "kobject add"
+event are:
+
+* FIRMWARE=firmware name
+* TIMEOUT=timeout value
+* ASYNC=whether or not the API request was asynchronous
+
+By default DEVPATH is set by the internal kernel kobject infrastructure.
+Below is an example simple kobject uevent script::
+
+        # Both $DEVPATH and $FIRMWARE are already provided in the environment.
+        MY_FW_DIR=/lib/firmware/
+        echo 1 > /sys/$DEVPATH/loading
+        cat $MY_FW_DIR/$FIRMWARE > /sys/$DEVPATH/data
+        echo 0 > /sys/$DEVPATH/loading
+
+Firmware custom fallback mechanism
+==================================
+
+Users of the request_firmware_nowait() call have yet another option available
+at their disposal: rely on the sysfs fallback mechanism but request that no
+kobject uevents be issued to userspace. The original logic behind this
+was that utilities other than udev might be required to lookup firmware
+in non-traditional paths -- paths outside of the listing documented in the
+section 'Direct filesystem lookup'. This option is not available to any of
+the other API calls as uevents are always forced for them.
+
+Since uevents are only meaningful if the fallback mechanism is enabled
+in your kernel it would seem odd to enable uevents with kernels that do not
+have the fallback mechanism enabled in their kernels. Unfortunately we also
+rely on the uevent flag which can be disabled by request_firmware_nowait() to
+also setup the firmware cache for firmware requests. As documented above,
+the firmware cache is only set up if uevent is enabled for an API call.
+Although this can disable the firmware cache for request_firmware_nowait()
+calls, users of this API should not use it for the purposes of disabling
+the cache as that was not the original purpose of the flag. Not setting
+the uevent flag means you want to opt-in for the firmware fallback mechanism
+but you want to suppress kobject uevents, as you have a custom solution which
+will monitor for your device addition into the device hierarchy somehow and
+load firmware for you through a custom path.
+
+Firmware fallback timeout
+=========================
+
+The firmware fallback mechanism has a timeout. If firmware is not loaded
+onto the sysfs interface by the timeout value an error is sent to the
+driver. By default the timeout is set to 60 seconds if uevents are
+desirable, otherwise MAX_JIFFY_OFFSET is used (max timeout possible).
+The logic behind using MAX_JIFFY_OFFSET for non-uevents is that a custom
+solution will have as much time as it needs to load firmware.
+
+You can customize the firmware timeout by echo'ing your desired timeout into
+the following file:
+
+* /sys/class/firmware/timeout
+
+If you echo 0 into it means MAX_JIFFY_OFFSET will be used. The data type
+for the timeout is an int.
+
+EFI embedded firmware fallback mechanism
+========================================
+
+On some devices the system's EFI code / ROM may contain an embedded copy
+of firmware for some of the system's integrated peripheral devices and
+the peripheral's Linux device-driver needs to access this firmware.
+
+Device drivers which need such firmware can use the
+firmware_request_platform() function for this, note that this is a
+separate fallback mechanism from the other fallback mechanisms and
+this does not use the sysfs interface.
+
+A device driver which needs this can describe the firmware it needs
+using an efi_embedded_fw_desc struct:
+
+.. kernel-doc:: include/linux/efi_embedded_fw.h
+   :functions: efi_embedded_fw_desc
+
+The EFI embedded-fw code works by scanning all EFI_BOOT_SERVICES_CODE memory
+segments for an eight byte sequence matching prefix; if the prefix is found it
+then does a sha256 over length bytes and if that matches makes a copy of length
+bytes and adds that to its list with found firmwares.
+
+To avoid doing this somewhat expensive scan on all systems, dmi matching is
+used. Drivers are expected to export a dmi_system_id array, with each entries'
+driver_data pointing to an efi_embedded_fw_desc.
+
+To register this array with the efi-embedded-fw code, a driver needs to:
+
+1. Always be builtin to the kernel or store the dmi_system_id array in a
+   separate object file which always gets builtin.
+
+2. Add an extern declaration for the dmi_system_id array to
+   include/linux/efi_embedded_fw.h.
+
+3. Add the dmi_system_id array to the embedded_fw_table in
+   drivers/firmware/efi/embedded-firmware.c wrapped in a #ifdef testing that
+   the driver is being builtin.
+
+4. Add "select EFI_EMBEDDED_FIRMWARE if EFI_STUB" to its Kconfig entry.
+
+The firmware_request_platform() function will always first try to load firmware
+with the specified name directly from the disk, so the EFI embedded-fw can
+always be overridden by placing a file under /lib/firmware.
+
+Note that:
+
+1. The code scanning for EFI embedded-firmware runs near the end
+   of start_kernel(), just before calling rest_init(). For normal drivers and
+   subsystems using subsys_initcall() to register themselves this does not
+   matter. This means that code running earlier cannot use EFI
+   embedded-firmware.
+
+2. At the moment the EFI embedded-fw code assumes that firmwares always start at
+   an offset which is a multiple of 8 bytes, if this is not true for your case
+   send in a patch to fix this.
+
+3. At the moment the EFI embedded-fw code only works on x86 because other archs
+   free EFI_BOOT_SERVICES_CODE before the EFI embedded-fw code gets a chance to
+   scan it.
+
+4. The current brute-force scanning of EFI_BOOT_SERVICES_CODE is an ad-hoc
+   brute-force solution. There has been discussion to use the UEFI Platform
+   Initialization (PI) spec's Firmware Volume protocol. This has been rejected
+   because the FV Protocol relies on *internal* interfaces of the PI spec, and:
+   1. The PI spec does not define peripheral firmware at all
+   2. The internal interfaces of the PI spec do not guarantee any backward
+   compatibility. Any implementation details in FV may be subject to change,
+   and may vary system to system. Supporting the FV Protocol would be
+   difficult as it is purposely ambiguous.
+
+Example how to check for and extract embedded firmware
+------------------------------------------------------
+
+To check for, for example Silead touchscreen controller embedded firmware,
+do the following:
+
+1. Boot the system with efi=debug on the kernel commandline
+
+2. cp /sys/kernel/debug/efi/boot_services_code? to your home dir
+
+3. Open the boot_services_code? files in a hex-editor, search for the
+   magic prefix for Silead firmware: F0 00 00 00 02 00 00 00, this gives you
+   the beginning address of the firmware inside the boot_services_code? file.
+
+4. The firmware has a specific pattern, it starts with a 8 byte page-address,
+   typically F0 00 00 00 02 00 00 00 for the first page followed by 32-bit
+   word-address + 32-bit value pairs. With the word-address incrementing 4
+   bytes (1 word) for each pair until a page is complete. A complete page is
+   followed by a new page-address, followed by more word + value pairs. This
+   leads to a very distinct pattern. Scroll down until this pattern stops,
+   this gives you the end of the firmware inside the boot_services_code? file.
+
+5. "dd if=boot_services_code? of=firmware bs=1 skip=<begin-addr> count=<len>"
+   will extract the firmware for you. Inspect the firmware file in a
+   hexeditor to make sure you got the dd parameters correct.
+
+6. Copy it to /lib/firmware under the expected name to test it.
+
+7. If the extracted firmware works, you can use the found info to fill an
+   efi_embedded_fw_desc struct to describe it, run "sha256sum firmware"
+   to get the sha256sum to put in the sha256 field.
diff --git a/Documentation/driver-api/firmware/firmware-usage-guidelines.rst b/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
new file mode 100644
index 000000000..336e91228
--- /dev/null
+++ b/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
@@ -0,0 +1,49 @@
+===================
+Firmware Guidelines
+===================
+
+Users switching to a newer kernel should *not* have to install newer
+firmware files to keep their hardware working. At the same time updated
+firmware files must not cause any regressions for users of older kernel
+releases.
+
+Drivers that use firmware from linux-firmware should follow the rules in
+this guide. (Where there is limited control of the firmware,
+i.e. company doesn't support Linux, firmwares sourced from misc places,
+then of course these rules will not apply strictly.)
+
+* Firmware files shall be designed in a way that it allows checking for
+  firmware ABI version changes. It is recommended that firmware files be
+  versioned with at least a major/minor version. It is suggested that
+  the firmware files in linux-firmware be named with some device
+  specific name, and just the major version. The firmware version should
+  be stored in the firmware header, or as an exception, as part of the
+  firmware file name, in order to let the driver detact any non-ABI
+  fixes/changes. The firmware files in linux-firmware should be
+  overwritten with the newest compatible major version. Newer major
+  version firmware shall remain compatible with all kernels that load
+  that major number.
+
+* If the kernel support for the hardware is normally inactive, or the
+  hardware isn't available for public consumption, this can
+  be ignored, until the first kernel release that enables that hardware.
+  This means no major version bumps without the kernel retaining
+  backwards compatibility for the older major versions.  Minor version
+  bumps should not introduce new features that newer kernels depend on
+  non-optionally.
+
+* If a security fix needs lockstep firmware and kernel fixes in order to
+  be successful, then all supported major versions in the linux-firmware
+  repo that are required by currently supported stable/LTS kernels,
+  should be updated with the security fix. The kernel patches should
+  detect if the firmware is new enough to declare if the security issue
+  is fixed.  All communications around security fixes should point at
+  both the firmware and kernel fixes. If a security fix requires
+  deprecating old major versions, then this should only be done as a
+  last option, and be stated clearly in all communications.
+
+* Firmware files that affect the User API (UAPI) shall not introduce
+  changes that break existing userspace programs. Updates to such firmware
+  must ensure backward compatibility with existing userspace applications.
+  This includes maintaining consistent interfaces and behaviors that
+  userspace programs rely on.
diff --git a/Documentation/driver-api/firmware/firmware_cache.rst b/Documentation/driver-api/firmware/firmware_cache.rst
new file mode 100644
index 000000000..417b9e834
--- /dev/null
+++ b/Documentation/driver-api/firmware/firmware_cache.rst
@@ -0,0 +1,51 @@
+==============
+Firmware cache
+==============
+
+When Linux resumes from suspend some device drivers require firmware lookups to
+re-initialize devices. During resume there may be a period of time during which
+firmware lookups are not possible, during this short period of time firmware
+requests will fail. Time is of essence though, and delaying drivers to wait for
+the root filesystem for firmware delays user experience with device
+functionality. In order to support these requirements the firmware
+infrastructure implements a firmware cache for device drivers for most API
+calls, automatically behind the scenes.
+
+The firmware cache makes using certain firmware API calls safe during a device
+driver's suspend and resume callback.  Users of these API calls needn't cache
+the firmware by themselves for dealing with firmware loss during system resume.
+
+The firmware cache works by requesting for firmware prior to suspend and
+caching it in memory. Upon resume device drivers using the firmware API will
+have access to the firmware immediately, without having to wait for the root
+filesystem to mount or dealing with possible race issues with lookups as the
+root filesystem mounts.
+
+Some implementation details about the firmware cache setup:
+
+* The firmware cache is setup by adding a devres entry for each device that
+  uses all synchronous call except :c:func:`request_firmware_into_buf`.
+
+* If an asynchronous call is used the firmware cache is only set up for a
+  device if the second argument (uevent) to request_firmware_nowait() is
+  true. When uevent is true it requests that a kobject uevent be sent to
+  userspace for the firmware request through the sysfs fallback mechanism
+  if the firmware file is not found.
+
+* If the firmware cache is determined to be needed as per the above two
+  criteria the firmware cache is setup by adding a devres entry for the
+  device making the firmware request.
+
+* The firmware devres entry is maintained throughout the lifetime of the
+  device. This means that even if you release_firmware() the firmware cache
+  will still be used on resume from suspend.
+
+* The timeout for the fallback mechanism is temporarily reduced to 10 seconds
+  as the firmware cache is set up during suspend, the timeout is set back to
+  the old value you had configured after the cache is set up.
+
+* Upon suspend any pending non-uevent firmware requests are killed to avoid
+  stalling the kernel, this is done with kill_requests_without_uevent(). Kernel
+  calls requiring the non-uevent therefore need to implement their own firmware
+  cache mechanism but must not use the firmware API on suspend.
+
diff --git a/Documentation/driver-api/firmware/fw_search_path.rst b/Documentation/driver-api/firmware/fw_search_path.rst
new file mode 100644
index 000000000..d7cb1e8f0
--- /dev/null
+++ b/Documentation/driver-api/firmware/fw_search_path.rst
@@ -0,0 +1,31 @@
+=====================
+Firmware search paths
+=====================
+
+The following search paths are used to look for firmware on your
+root filesystem.
+
+* fw_path_para - module parameter - default is empty so this is ignored
+* /lib/firmware/updates/UTS_RELEASE/
+* /lib/firmware/updates/
+* /lib/firmware/UTS_RELEASE/
+* /lib/firmware/
+
+The module parameter ''path'' can be passed to the firmware_class module
+to activate the first optional custom fw_path_para. The custom path can
+only be up to 256 characters long. The kernel parameter passed would be:
+
+* 'firmware_class.path=$CUSTOMIZED_PATH'
+
+There is an alternative to customize the path at run time after bootup, you
+can use the file:
+
+* /sys/module/firmware_class/parameters/path
+
+You would echo into it your custom path and firmware requested will be searched
+for there first. Be aware that newline characters will be taken into account
+and may not produce the intended effects. For instance you might want to use:
+
+echo -n /path/to/script > /sys/module/firmware_class/parameters/path
+
+to ensure that your script is being used.
diff --git a/Documentation/driver-api/firmware/fw_upload.rst b/Documentation/driver-api/firmware/fw_upload.rst
new file mode 100644
index 000000000..edf1d0c5e
--- /dev/null
+++ b/Documentation/driver-api/firmware/fw_upload.rst
@@ -0,0 +1,127 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================
+Firmware Upload API
+===================
+
+A device driver that registers with the firmware loader will expose
+persistent sysfs nodes to enable users to initiate firmware updates for
+that device.  It is the responsibility of the device driver and/or the
+device itself to perform any validation on the data received. Firmware
+upload uses the same *loading* and *data* sysfs files described in the
+documentation for firmware fallback. It also adds additional sysfs files
+to provide status on the transfer of the firmware image to the device.
+
+Register for firmware upload
+============================
+
+A device driver registers for firmware upload by calling
+firmware_upload_register(). Among the parameter list is a name to
+identify the device under /sys/class/firmware. A user may initiate a
+firmware upload by echoing a 1 to the *loading* sysfs file for the target
+device. Next, the user writes the firmware image to the *data* sysfs
+file. After writing the firmware data, the user echos 0 to the *loading*
+sysfs file to signal completion. Echoing 0 to *loading* also triggers the
+transfer of the firmware to the lower-lever device driver in the context
+of a kernel worker thread.
+
+To use the firmware upload API, write a driver that implements a set of
+ops.  The probe function calls firmware_upload_register() and the remove
+function calls firmware_upload_unregister() such as::
+
+	static const struct fw_upload_ops m10bmc_ops = {
+		.prepare = m10bmc_sec_prepare,
+		.write = m10bmc_sec_write,
+		.poll_complete = m10bmc_sec_poll_complete,
+		.cancel = m10bmc_sec_cancel,
+		.cleanup = m10bmc_sec_cleanup,
+	};
+
+	static int m10bmc_sec_probe(struct platform_device *pdev)
+	{
+		const char *fw_name, *truncate;
+		struct m10bmc_sec *sec;
+		struct fw_upload *fwl;
+		unsigned int len;
+
+		sec = devm_kzalloc(&pdev->dev, sizeof(*sec), GFP_KERNEL);
+		if (!sec)
+			return -ENOMEM;
+
+		sec->dev = &pdev->dev;
+		sec->m10bmc = dev_get_drvdata(pdev->dev.parent);
+		dev_set_drvdata(&pdev->dev, sec);
+
+		fw_name = dev_name(sec->dev);
+		truncate = strstr(fw_name, ".auto");
+		len = (truncate) ? truncate - fw_name : strlen(fw_name);
+		sec->fw_name = kmemdup_nul(fw_name, len, GFP_KERNEL);
+
+		fwl = firmware_upload_register(THIS_MODULE, sec->dev, sec->fw_name,
+					       &m10bmc_ops, sec);
+		if (IS_ERR(fwl)) {
+			dev_err(sec->dev, "Firmware Upload driver failed to start\n");
+			kfree(sec->fw_name);
+			return PTR_ERR(fwl);
+		}
+
+		sec->fwl = fwl;
+		return 0;
+	}
+
+	static int m10bmc_sec_remove(struct platform_device *pdev)
+	{
+		struct m10bmc_sec *sec = dev_get_drvdata(&pdev->dev);
+
+		firmware_upload_unregister(sec->fwl);
+		kfree(sec->fw_name);
+		return 0;
+	}
+
+firmware_upload_register
+------------------------
+.. kernel-doc:: drivers/base/firmware_loader/sysfs_upload.c
+   :identifiers: firmware_upload_register
+
+firmware_upload_unregister
+--------------------------
+.. kernel-doc:: drivers/base/firmware_loader/sysfs_upload.c
+   :identifiers: firmware_upload_unregister
+
+Firmware Upload Ops
+-------------------
+.. kernel-doc:: include/linux/firmware.h
+   :identifiers: fw_upload_ops
+
+Firmware Upload Progress Codes
+------------------------------
+The following progress codes are used internally by the firmware loader.
+Corresponding strings are reported through the status sysfs node that
+is described below and are documented in the ABI documentation.
+
+.. kernel-doc:: drivers/base/firmware_loader/sysfs_upload.h
+   :identifiers: fw_upload_prog
+
+Firmware Upload Error Codes
+---------------------------
+The following error codes may be returned by the driver ops in case of
+failure:
+
+.. kernel-doc:: include/linux/firmware.h
+   :identifiers: fw_upload_err
+
+Sysfs Attributes
+================
+
+In addition to the *loading* and *data* sysfs files, there are additional
+sysfs files to monitor the status of the data transfer to the target
+device and to determine the final pass/fail status of the transfer.
+Depending on the device and the size of the firmware image, a firmware
+update could take milliseconds or minutes.
+
+The additional sysfs files are:
+
+* status - provides an indication of the progress of a firmware update
+* error - provides error information for a failed firmware update
+* remaining_size - tracks the data transfer portion of an update
+* cancel - echo 1 to this file to cancel the update
diff --git a/Documentation/driver-api/firmware/index.rst b/Documentation/driver-api/firmware/index.rst
new file mode 100644
index 000000000..86a3dd4bc
--- /dev/null
+++ b/Documentation/driver-api/firmware/index.rst
@@ -0,0 +1,12 @@
+==================
+Linux Firmware API
+==================
+
+.. toctree::
+
+   introduction
+   core
+   efi/index
+   request_firmware
+   fw_upload
+   other_interfaces
diff --git a/Documentation/driver-api/firmware/introduction.rst b/Documentation/driver-api/firmware/introduction.rst
new file mode 100644
index 000000000..211cb44eb
--- /dev/null
+++ b/Documentation/driver-api/firmware/introduction.rst
@@ -0,0 +1,27 @@
+============
+Introduction
+============
+
+The firmware API enables kernel code to request files required
+for functionality from userspace, the uses vary:
+
+* Microcode for CPU errata
+* Device driver firmware, required to be loaded onto device
+  microcontrollers
+* Device driver information data (calibration data, EEPROM overrides),
+  some of which can be completely optional.
+
+Types of firmware requests
+==========================
+
+There are two types of calls:
+
+* Synchronous
+* Asynchronous
+
+Which one you use vary depending on your requirements, the rule of thumb
+however is you should strive to use the asynchronous APIs unless you also
+are already using asynchronous initialization mechanisms which will not
+stall or delay boot. Even if loading firmware does not take a lot of time
+processing firmware might, and this can still delay boot or initialization,
+as such mechanisms such as asynchronous probe can help supplement drivers.
diff --git a/Documentation/driver-api/firmware/lookup-order.rst b/Documentation/driver-api/firmware/lookup-order.rst
new file mode 100644
index 000000000..6064672a7
--- /dev/null
+++ b/Documentation/driver-api/firmware/lookup-order.rst
@@ -0,0 +1,20 @@
+=====================
+Firmware lookup order
+=====================
+
+Different functionality is available to enable firmware to be found.
+Below is chronological order of how firmware will be looked for once
+a driver issues a firmware API call.
+
+* The ''Built-in firmware'' is checked first, if the firmware is present we
+  return it immediately
+* The ''Firmware cache'' is looked at next. If the firmware is found we
+  return it immediately
+* The ''Direct filesystem lookup'' is performed next, if found we
+  return it immediately
+* The ''Platform firmware fallback'' is performed next, but only when
+  firmware_request_platform() is used, if found we return it immediately
+* If no firmware has been found and the fallback mechanism was enabled
+  the sysfs interface is created. After this either a kobject uevent
+  is issued or the custom firmware loading is relied upon for firmware
+  loading up to the timeout value.
diff --git a/Documentation/driver-api/firmware/other_interfaces.rst b/Documentation/driver-api/firmware/other_interfaces.rst
new file mode 100644
index 000000000..06ac89ada
--- /dev/null
+++ b/Documentation/driver-api/firmware/other_interfaces.rst
@@ -0,0 +1,51 @@
+Other Firmware Interfaces
+=========================
+
+DMI Interfaces
+--------------
+
+.. kernel-doc:: drivers/firmware/dmi_scan.c
+   :export:
+
+EDD Interfaces
+--------------
+
+.. kernel-doc:: drivers/firmware/edd.c
+   :internal:
+
+Generic System Framebuffers Interface
+-------------------------------------
+
+.. kernel-doc:: drivers/firmware/sysfb.c
+   :export:
+
+Intel Stratix10 SoC Service Layer
+---------------------------------
+Some features of the Intel Stratix10 SoC require a level of privilege
+higher than the kernel is granted. Such secure features include
+FPGA programming. In terms of the ARMv8 architecture, the kernel runs
+at Exception Level 1 (EL1), access to the features requires
+Exception Level 3 (EL3).
+
+The Intel Stratix10 SoC service layer provides an in kernel API for
+drivers to request access to the secure features. The requests are queued
+and processed one by one. ARM’s SMCCC is used to pass the execution
+of the requests on to a secure monitor (EL3).
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_command_code
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_client_msg
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_command_config_type
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_cb_data
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_client
+
+.. kernel-doc:: drivers/firmware/stratix10-svc.c
+   :export:
diff --git a/Documentation/driver-api/firmware/request_firmware.rst b/Documentation/driver-api/firmware/request_firmware.rst
new file mode 100644
index 000000000..0d6ea0329
--- /dev/null
+++ b/Documentation/driver-api/firmware/request_firmware.rst
@@ -0,0 +1,80 @@
+====================
+request_firmware API
+====================
+
+You would typically load firmware and then load it into your device somehow.
+The typical firmware work flow is reflected below::
+
+	 if(request_firmware(&fw_entry, $FIRMWARE, device) == 0)
+                copy_fw_to_device(fw_entry->data, fw_entry->size);
+	 release_firmware(fw_entry);
+
+Synchronous firmware requests
+=============================
+
+Synchronous firmware requests will wait until the firmware is found or until
+an error is returned.
+
+request_firmware
+----------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: request_firmware
+
+firmware_request_nowarn
+-----------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: firmware_request_nowarn
+
+firmware_request_platform
+-------------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: firmware_request_platform
+
+request_firmware_direct
+-----------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: request_firmware_direct
+
+request_firmware_into_buf
+-------------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: request_firmware_into_buf
+
+Asynchronous firmware requests
+==============================
+
+Asynchronous firmware requests allow driver code to not have to wait
+until the firmware or an error is returned. Function callbacks are
+provided so that when the firmware or an error is found the driver is
+informed through the callback. request_firmware_nowait() cannot be called
+in atomic contexts.
+
+request_firmware_nowait
+-----------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: request_firmware_nowait
+
+Special optimizations on reboot
+===============================
+
+Some devices have an optimization in place to enable the firmware to be
+retained during system reboot. When such optimizations are used the driver
+author must ensure the firmware is still available on resume from suspend,
+this can be done with firmware_request_cache() instead of requesting for the
+firmware to be loaded.
+
+firmware_request_cache()
+------------------------
+.. kernel-doc:: drivers/base/firmware_loader/main.c
+   :functions: firmware_request_cache
+
+request firmware API expected driver use
+========================================
+
+Once an API call returns you process the firmware and then release the
+firmware. For example if you used request_firmware() and it returns,
+the driver has the firmware image accessible in fw_entry->{data,size}.
+If something went wrong request_firmware() returns non-zero and fw_entry
+is set to NULL. Once your driver is done with processing the firmware it
+can call release_firmware(fw_entry) to release the firmware image
+and any related resource.