Resguardo inicial

linux-7.2.3/drivers/base/firmware_loader/Kconfig

@@ -0,0 +1,239 @@
+# SPDX-License-Identifier: GPL-2.0
+menu "Firmware loader"
+
+config FW_LOADER
+	tristate "Firmware loading facility" if EXPERT
+	select CRYPTO_LIB_SHA256 if FW_LOADER_DEBUG
+	default y
+	help
+	  This enables the firmware loading facility in the kernel. The kernel
+	  will first look for built-in firmware, if it has any. Next, it will
+	  look for the requested firmware in a series of filesystem paths:
+
+		o firmware_class path module parameter or kernel boot param
+		o /lib/firmware/updates/UTS_RELEASE
+		o /lib/firmware/updates
+		o /lib/firmware/UTS_RELEASE
+		o /lib/firmware
+
+	  Enabling this feature only increases your kernel image by about
+	  828 bytes, enable this option unless you are certain you don't
+	  need firmware.
+
+	  You typically want this built-in (=y) but you can also enable this
+	  as a module, in which case the firmware_class module will be built.
+	  You also want to be sure to enable this built-in if you are going to
+	  enable built-in firmware (CONFIG_EXTRA_FIRMWARE).
+
+config FW_LOADER_DEBUG
+	bool "Log filenames and checksums for loaded firmware"
+	depends on DYNAMIC_DEBUG
+	depends on FW_LOADER
+	default FW_LOADER
+	help
+	  Select this option to use dynamic debug to log firmware filenames and
+	  SHA256 checksums to the kernel log for each firmware file that is
+	  loaded.
+
+config RUST_FW_LOADER_ABSTRACTIONS
+	bool "Rust Firmware Loader abstractions"
+	depends on RUST
+	select FW_LOADER
+	help
+	  This enables the Rust abstractions for the firmware loader API.
+
+if FW_LOADER
+
+config FW_LOADER_PAGED_BUF
+	bool
+
+config FW_LOADER_SYSFS
+	bool
+
+config EXTRA_FIRMWARE
+	string "Build named firmware blobs into the kernel binary"
+	help
+	  Device drivers which require firmware can typically deal with
+	  having the kernel load firmware from the various supported
+	  /lib/firmware/ paths. This option enables you to build into the
+	  kernel firmware files. Built-in firmware searches are preceded
+	  over firmware lookups using your filesystem over the supported
+	  /lib/firmware paths documented on CONFIG_FW_LOADER.
+
+	  This may be useful for testing or if the firmware is required early on
+	  in boot and cannot rely on the firmware being placed in an initrd or
+	  initramfs.
+
+	  This option is a string and takes the (space-separated) names of the
+	  firmware files -- the same names that appear in MODULE_FIRMWARE()
+	  and request_firmware() in the source. These files should exist under
+	  the directory specified by the EXTRA_FIRMWARE_DIR option, which is
+	  /lib/firmware by default.
+
+	  For example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin", copy
+	  the usb8388.bin file into /lib/firmware, and build the kernel. Then
+	  any request_firmware("usb8388.bin") will be satisfied internally
+	  inside the kernel without ever looking at your filesystem at runtime.
+
+	  WARNING: If you include additional firmware files into your binary
+	  kernel image that are not available under the terms of the GPL,
+	  then it may be a violation of the GPL to distribute the resulting
+	  image since it combines both GPL and non-GPL work. You should
+	  consult a lawyer of your own before distributing such an image.
+
+	  NOTE: Compressed files are not supported in EXTRA_FIRMWARE.
+
+config EXTRA_FIRMWARE_DIR
+	string "Firmware blobs root directory"
+	depends on EXTRA_FIRMWARE != ""
+	default "/lib/firmware"
+	help
+	  This option controls the directory in which the kernel build system
+	  looks for the firmware files listed in the EXTRA_FIRMWARE option.
+
+config FW_LOADER_USER_HELPER
+	bool "Enable the firmware sysfs fallback mechanism"
+	select FW_LOADER_SYSFS
+	select FW_LOADER_PAGED_BUF
+	help
+	  This option enables a sysfs loading facility to enable firmware
+	  loading to the kernel through userspace as a fallback mechanism
+	  if and only if the kernel's direct filesystem lookup for the
+	  firmware failed using the different /lib/firmware/ paths, or the
+	  path specified in the firmware_class path module parameter, or the
+	  firmware_class path kernel boot parameter if the firmware_class is
+	  built-in. For details on how to work with the sysfs fallback mechanism
+	  refer to Documentation/driver-api/firmware/fallback-mechanisms.rst.
+
+	  The direct filesystem lookup for firmware is always used first now.
+
+	  If the kernel's direct filesystem lookup for firmware fails to find
+	  the requested firmware a sysfs fallback loading facility is made
+	  available and userspace is informed about this through uevents.
+	  The uevent can be suppressed if the driver explicitly requested it,
+	  this is known as the driver using the custom fallback mechanism.
+	  If the custom fallback mechanism is used userspace must always
+	  acknowledge failure to find firmware as the timeout for the fallback
+	  mechanism is disabled, and failed requests will linger forever.
+
+	  This used to be the default firmware loading facility, and udev used
+	  to listen for uvents to load firmware for the kernel. The firmware
+	  loading facility functionality in udev has been removed, as such it
+	  can no longer be relied upon as a fallback mechanism. Linux no longer
+	  relies on or uses a fallback mechanism in userspace. If you need to
+	  rely on one refer to the permissively licensed firmwared:
+
+	  https://github.com/teg/firmwared
+
+	  Since this was the default firmware loading facility at one point,
+	  old userspace may exist which relies upon it, and as such this
+	  mechanism can never be removed from the kernel.
+
+	  You should only enable this functionality if you are certain you
+	  require a fallback mechanism and have a userspace mechanism ready to
+	  load firmware in case it is not found. One main reason for this may
+	  be if you have drivers which require firmware built-in and for
+	  whatever reason cannot place the required firmware in initramfs.
+	  Another reason kernels may have this feature enabled is to support a
+	  driver which explicitly relies on this fallback mechanism. Only two
+	  drivers need this today:
+
+	    o CONFIG_LEDS_LP55XX_COMMON
+	    o CONFIG_DELL_RBU
+
+	  Outside of supporting the above drivers, another reason for needing
+	  this may be that your firmware resides outside of the paths the kernel
+	  looks for and cannot possibly be specified using the firmware_class
+	  path module parameter or kernel firmware_class path boot parameter
+	  if firmware_class is built-in.
+
+	  A modern use case may be to temporarily mount a custom partition
+	  during provisioning which is only accessible to userspace, and then
+	  to use it to look for and fetch the required firmware. Such type of
+	  driver functionality may not even ever be desirable upstream by
+	  vendors, and as such is only required to be supported as an interface
+	  for provisioning. Since udev's firmware loading facility has been
+	  removed you can use firmwared or a fork of it to customize how you
+	  want to load firmware based on uevents issued.
+
+	  Enabling this option will increase your kernel image size by about
+	  13436 bytes.
+
+	  If you are unsure about this, say N here, unless you are Linux
+	  distribution and need to support the above two drivers, or you are
+	  certain you need to support some really custom firmware loading
+	  facility in userspace.
+
+config FW_LOADER_USER_HELPER_FALLBACK
+	bool "Force the firmware sysfs fallback mechanism when possible"
+	depends on FW_LOADER_USER_HELPER
+	help
+	  Enabling this option forces a sysfs userspace fallback mechanism
+	  to be used for all firmware requests which explicitly do not disable a
+	  a fallback mechanism. Firmware calls which do prohibit a fallback
+	  mechanism is request_firmware_direct(). This option is kept for
+	  backward compatibility purposes given this precise mechanism can also
+	  be enabled by setting the proc sysctl value to true:
+
+	       /proc/sys/kernel/firmware_config/force_sysfs_fallback
+
+	  If you are unsure about this, say N here.
+
+config FW_LOADER_COMPRESS
+	bool "Enable compressed firmware support"
+	help
+	  This option enables the support for loading compressed firmware
+	  files. The caller of firmware API receives the decompressed file
+	  content. The compressed file is loaded as a fallback, only after
+	  loading the raw file failed at first.
+
+	  Compressed firmware support does not apply to firmware images
+	  that are built into the kernel image (CONFIG_EXTRA_FIRMWARE).
+
+if FW_LOADER_COMPRESS
+config FW_LOADER_COMPRESS_XZ
+	bool "Enable XZ-compressed firmware support"
+	select FW_LOADER_PAGED_BUF
+	select XZ_DEC
+	default y
+	help
+	  This option adds the support for XZ-compressed files.
+	  The files have to be compressed with either none or crc32
+	  integrity check type (pass "-C crc32" option to xz command).
+
+config FW_LOADER_COMPRESS_ZSTD
+	bool "Enable ZSTD-compressed firmware support"
+	select ZSTD_DECOMPRESS
+	help
+	  This option adds the support for ZSTD-compressed files.
+
+endif # FW_LOADER_COMPRESS
+
+config FW_CACHE
+	bool "Enable firmware caching during suspend"
+	depends on PM_SLEEP
+	default y if PM_SLEEP
+	help
+	  Because firmware caching generates uevent messages that are sent
+	  over a netlink socket, it can prevent suspend on many platforms.
+	  It is also not always useful, so on such platforms we have the
+	  option.
+
+	  If unsure, say Y.
+
+config FW_UPLOAD
+	bool "Enable users to initiate firmware updates using sysfs"
+	select FW_LOADER_SYSFS
+	select FW_LOADER_PAGED_BUF
+	help
+	  Enabling this option will allow device drivers to expose a persistent
+	  sysfs interface that allows firmware updates to be initiated from
+	  userspace. For example, FPGA based PCIe cards load firmware and FPGA
+	  images from local FLASH when the card boots. The images in FLASH may
+	  be updated with new images provided by the user. Enable this device
+	  to support cards that rely on user-initiated updates for firmware files.
+
+	  If unsure, say N.
+
+endif # FW_LOADER
+endmenu

linux-7.2.3/drivers/base/firmware_loader/Makefile

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for the Linux firmware loader
+
+obj-$(CONFIG_FW_LOADER_USER_HELPER) += fallback_table.o
+obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
+firmware_class-objs := main.o
+firmware_class-$(CONFIG_FW_LOADER_USER_HELPER) += fallback.o
+firmware_class-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += fallback_platform.o
+firmware_class-$(CONFIG_FW_LOADER_SYSFS) += sysfs.o
+firmware_class-$(CONFIG_FW_UPLOAD) += sysfs_upload.o
+
+obj-y += builtin/

linux-7.2.3/drivers/base/firmware_loader/builtin/.gitignore

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+*.gen.S

linux-7.2.3/drivers/base/firmware_loader/builtin/Makefile

@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y  += main.o
+
+# Create $(fwdir) from $(CONFIG_EXTRA_FIRMWARE_DIR) -- if it doesn't have a
+# leading /, it's relative to $(srctree).
+fwdir := $(CONFIG_EXTRA_FIRMWARE_DIR)
+fwdir := $(addprefix $(srctree)/,$(filter-out /%,$(fwdir)))$(filter /%,$(fwdir))
+
+firmware  := $(addsuffix .gen.o, $(CONFIG_EXTRA_FIRMWARE))
+obj-y += $(firmware)
+
+FWNAME    = $(patsubst $(obj)/%.gen.S,%,$@)
+FWSTR     = $(subst $(comma),_,$(subst /,_,$(subst .,_,$(subst -,_,$(FWNAME)))))
+ASM_WORD  = $(if $(CONFIG_64BIT),.quad,.long)
+ASM_ALIGN = $(if $(CONFIG_64BIT),3,2)
+PROGBITS  = $(if $(CONFIG_ARM),%,@)progbits
+
+filechk_fwbin = \
+	echo "/* Generated by $(src)/Makefile */"		;\
+	echo "    .section .rodata"				;\
+	echo "    .p2align 4"					;\
+	echo "_fw_$(FWSTR)_bin:"				;\
+	echo "    .incbin \"$(fwdir)/$(FWNAME)\""		;\
+	echo "_fw_end:"						;\
+	echo "    .section .rodata.str,\"aMS\",$(PROGBITS),1"	;\
+	echo "    .p2align $(ASM_ALIGN)"			;\
+	echo "_fw_$(FWSTR)_name:"				;\
+	echo "    .string \"$(FWNAME)\""			;\
+	echo "    .section .builtin_fw,\"a\",$(PROGBITS)"	;\
+	echo "    .p2align $(ASM_ALIGN)"			;\
+	echo "    $(ASM_WORD) _fw_$(FWSTR)_name"		;\
+	echo "    $(ASM_WORD) _fw_$(FWSTR)_bin"			;\
+	echo "    $(ASM_WORD) _fw_end - _fw_$(FWSTR)_bin"
+
+$(obj)/%.gen.S: FORCE
+	$(call filechk,fwbin)
+
+# The .o files depend on the binaries directly; the .S files don't.
+$(addprefix $(obj)/, $(firmware)): $(obj)/%.gen.o: $(fwdir)/%
+
+targets := $(patsubst $(obj)/%,%, \
+                                $(shell find $(obj) -name \*.gen.S 2>/dev/null))

linux-7.2.3/drivers/base/firmware_loader/builtin/main.c

@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Builtin firmware support */
+
+#include <linux/firmware.h>
+#include "../firmware.h"
+
+/* Only if FW_LOADER=y */
+#ifdef CONFIG_FW_LOADER
+
+struct builtin_fw {
+	char *name;
+	void *data;
+	unsigned long size;
+};
+
+extern struct builtin_fw __start_builtin_fw[];
+extern struct builtin_fw __end_builtin_fw[];
+
+static bool fw_copy_to_prealloc_buf(struct firmware *fw,
+				    void *buf, size_t size)
+{
+	if (!buf)
+		return true;
+	if (size < fw->size)
+		return false;
+	memcpy(buf, fw->data, fw->size);
+	return true;
+}
+
+/**
+ * firmware_request_builtin() - load builtin firmware
+ * @fw: pointer to firmware struct
+ * @name: name of firmware file
+ *
+ * Some use cases in the kernel have a requirement so that no memory allocator
+ * is involved as these calls take place early in boot process. An example is
+ * the x86 CPU microcode loader. In these cases all the caller wants is to see
+ * if the firmware was built-in and if so use it right away. This can be used
+ * for such cases.
+ *
+ * This looks for the firmware in the built-in kernel. Only if the kernel was
+ * built-in with the firmware you are looking for will this return successfully.
+ *
+ * Callers of this API do not need to use release_firmware() as the pointer to
+ * the firmware is expected to be provided locally on the stack of the caller.
+ **/
+bool firmware_request_builtin(struct firmware *fw, const char *name)
+{
+	struct builtin_fw *b_fw;
+
+	if (!fw)
+		return false;
+
+	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
+		if (strcmp(name, b_fw->name) == 0) {
+			fw->size = b_fw->size;
+			fw->data = b_fw->data;
+			return true;
+		}
+	}
+
+	return false;
+}
+EXPORT_SYMBOL_NS_GPL(firmware_request_builtin, "TEST_FIRMWARE");
+
+/**
+ * firmware_request_builtin_buf() - load builtin firmware into optional buffer
+ * @fw: pointer to firmware struct
+ * @name: name of firmware file
+ * @buf: If set this lets you use a pre-allocated buffer so that the built-in
+ *	firmware into is copied into. This field can be NULL. It is used by
+ *	callers such as request_firmware_into_buf() and
+ *	request_partial_firmware_into_buf()
+ * @size: if buf was provided, the max size of the allocated buffer available.
+ *	If the built-in firmware does not fit into the pre-allocated @buf this
+ *	call will fail.
+ *
+ * This looks for the firmware in the built-in kernel. Only if the kernel was
+ * built-in with the firmware you are looking for will this call possibly
+ * succeed. If you passed a @buf the firmware will be copied into it *iff* the
+ * built-in firmware fits into the pre-allocated buffer size specified in
+ * @size.
+ *
+ * This caller is to be used internally by the firmware_loader only.
+ **/
+bool firmware_request_builtin_buf(struct firmware *fw, const char *name,
+				  void *buf, size_t size)
+{
+	if (!firmware_request_builtin(fw, name))
+		return false;
+
+	return fw_copy_to_prealloc_buf(fw, buf, size);
+}
+
+bool firmware_is_builtin(const struct firmware *fw)
+{
+	struct builtin_fw *b_fw;
+
+	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
+		if (fw->data == b_fw->data)
+			return true;
+
+	return false;
+}
+
+#endif

linux-7.2.3/drivers/base/firmware_loader/fallback.c

@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/kconfig.h>
+#include <linux/list.h>
+#include <linux/security.h>
+#include <linux/umh.h>
+#include <linux/sysctl.h>
+#include <linux/module.h>
+
+#include "fallback.h"
+#include "firmware.h"
+
+/*
+ * firmware fallback mechanism
+ */
+
+/*
+ * use small loading timeout for caching devices' firmware because all these
+ * firmware images have been loaded successfully at lease once, also system is
+ * ready for completing firmware loading now. The maximum size of firmware in
+ * current distributions is about 2M bytes, so 10 secs should be enough.
+ */
+void fw_fallback_set_cache_timeout(void)
+{
+	fw_fallback_config.old_timeout = __firmware_loading_timeout();
+	__fw_fallback_set_timeout(10);
+}
+
+/* Restores the timeout to the value last configured during normal operation */
+void fw_fallback_set_default_timeout(void)
+{
+	__fw_fallback_set_timeout(fw_fallback_config.old_timeout);
+}
+
+static long firmware_loading_timeout(void)
+{
+	return __firmware_loading_timeout() > 0 ?
+		__firmware_loading_timeout() * HZ : MAX_JIFFY_OFFSET;
+}
+
+static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv,  long timeout)
+{
+	return __fw_state_wait_common(fw_priv, timeout);
+}
+
+static LIST_HEAD(pending_fw_head);
+
+void kill_pending_fw_fallback_reqs(bool kill_all)
+{
+	struct fw_priv *fw_priv;
+	struct fw_priv *next;
+
+	mutex_lock(&fw_lock);
+	list_for_each_entry_safe(fw_priv, next, &pending_fw_head,
+				 pending_list) {
+		if (kill_all || !fw_priv->need_uevent)
+			 __fw_load_abort(fw_priv);
+	}
+
+	if (kill_all)
+		fw_load_abort_all = true;
+
+	mutex_unlock(&fw_lock);
+}
+
+/**
+ * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism
+ * @fw_sysfs: firmware sysfs information for the firmware to load
+ * @timeout: timeout to wait for the load
+ *
+ * In charge of constructing a sysfs fallback interface for firmware loading.
+ **/
+static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, long timeout)
+{
+	int retval = 0;
+	struct device *f_dev = &fw_sysfs->dev;
+	struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+
+	/* fall back on userspace loading */
+	if (!fw_priv->data)
+		fw_priv->is_paged_buf = true;
+
+	dev_set_uevent_suppress(f_dev, true);
+
+	retval = device_add(f_dev);
+	if (retval) {
+		dev_err(f_dev, "%s: device_register failed\n", __func__);
+		goto err_put_dev;
+	}
+
+	mutex_lock(&fw_lock);
+	if (fw_load_abort_all || fw_state_is_aborted(fw_priv)) {
+		mutex_unlock(&fw_lock);
+		retval = -EINTR;
+		goto out;
+	}
+	list_add(&fw_priv->pending_list, &pending_fw_head);
+	mutex_unlock(&fw_lock);
+
+	if (fw_priv->opt_flags & FW_OPT_UEVENT) {
+		fw_priv->need_uevent = true;
+		dev_set_uevent_suppress(f_dev, false);
+		dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name);
+		kobject_uevent(&fw_sysfs->dev.kobj, KOBJ_ADD);
+	} else {
+		timeout = MAX_JIFFY_OFFSET;
+	}
+
+	retval = fw_sysfs_wait_timeout(fw_priv, timeout);
+	if (retval < 0 && retval != -ENOENT) {
+		mutex_lock(&fw_lock);
+		fw_load_abort(fw_sysfs);
+		mutex_unlock(&fw_lock);
+	}
+
+	if (fw_state_is_aborted(fw_priv)) {
+		if (retval == -ERESTARTSYS)
+			retval = -EINTR;
+	} else if (fw_priv->is_paged_buf && !fw_priv->data)
+		retval = -ENOMEM;
+
+out:
+	device_del(f_dev);
+err_put_dev:
+	put_device(f_dev);
+	return retval;
+}
+
+static int fw_load_from_user_helper(struct firmware *firmware,
+				    const char *name, struct device *device,
+				    u32 opt_flags)
+{
+	struct fw_sysfs *fw_sysfs;
+	long timeout;
+	int ret;
+
+	timeout = firmware_loading_timeout();
+	if (opt_flags & FW_OPT_NOWAIT) {
+		timeout = usermodehelper_read_lock_wait(timeout);
+		if (!timeout) {
+			dev_dbg(device, "firmware: %s loading timed out\n",
+				name);
+			return -EBUSY;
+		}
+	} else {
+		ret = usermodehelper_read_trylock();
+		if (WARN_ON(ret)) {
+			dev_err(device, "firmware: %s will not be loaded\n",
+				name);
+			return ret;
+		}
+	}
+
+	fw_sysfs = fw_create_instance(firmware, name, device, opt_flags);
+	if (IS_ERR(fw_sysfs)) {
+		ret = PTR_ERR(fw_sysfs);
+		goto out_unlock;
+	}
+
+	fw_sysfs->fw_priv = firmware->priv;
+	ret = fw_load_sysfs_fallback(fw_sysfs, timeout);
+
+	if (!ret)
+		ret = assign_fw(firmware, device);
+
+out_unlock:
+	usermodehelper_read_unlock();
+
+	return ret;
+}
+
+static bool fw_force_sysfs_fallback(u32 opt_flags)
+{
+	if (fw_fallback_config.force_sysfs_fallback)
+		return true;
+	if (!(opt_flags & FW_OPT_USERHELPER))
+		return false;
+	return true;
+}
+
+static bool fw_run_sysfs_fallback(u32 opt_flags)
+{
+	int ret;
+
+	if (fw_fallback_config.ignore_sysfs_fallback) {
+		pr_info_once("Ignoring firmware sysfs fallback due to sysctl knob\n");
+		return false;
+	}
+
+	if ((opt_flags & FW_OPT_NOFALLBACK_SYSFS))
+		return false;
+
+	/* Also permit LSMs and IMA to fail firmware sysfs fallback */
+	ret = security_kernel_load_data(LOADING_FIRMWARE, true);
+	if (ret < 0)
+		return false;
+
+	return fw_force_sysfs_fallback(opt_flags);
+}
+
+/**
+ * firmware_fallback_sysfs() - use the fallback mechanism to find firmware
+ * @fw: pointer to firmware image
+ * @name: name of firmware file to look for
+ * @device: device for which firmware is being loaded
+ * @opt_flags: options to control firmware loading behaviour, as defined by
+ *	       &enum fw_opt
+ * @ret: return value from direct lookup which triggered the fallback mechanism
+ *
+ * This function is called if direct lookup for the firmware failed, it enables
+ * a fallback mechanism through userspace by exposing a sysfs loading
+ * interface. Userspace is in charge of loading the firmware through the sysfs
+ * loading interface. This sysfs fallback mechanism may be disabled completely
+ * on a system by setting the proc sysctl value ignore_sysfs_fallback to true.
+ * If this is false we check if the internal API caller set the
+ * @FW_OPT_NOFALLBACK_SYSFS flag, if so it would also disable the fallback
+ * mechanism. A system may want to enforce the sysfs fallback mechanism at all
+ * times, it can do this by setting ignore_sysfs_fallback to false and
+ * force_sysfs_fallback to true.
+ * Enabling force_sysfs_fallback is functionally equivalent to build a kernel
+ * with CONFIG_FW_LOADER_USER_HELPER_FALLBACK.
+ **/
+int firmware_fallback_sysfs(struct firmware *fw, const char *name,
+			    struct device *device,
+			    u32 opt_flags,
+			    int ret)
+{
+	if (!fw_run_sysfs_fallback(opt_flags))
+		return ret;
+
+	if (!(opt_flags & FW_OPT_NO_WARN))
+		dev_warn(device, "Falling back to sysfs fallback for: %s\n",
+				 name);
+	else
+		dev_dbg(device, "Falling back to sysfs fallback for: %s\n",
+				name);
+	return fw_load_from_user_helper(fw, name, device, opt_flags);
+}

linux-7.2.3/drivers/base/firmware_loader/fallback.h

@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __FIRMWARE_FALLBACK_H
+#define __FIRMWARE_FALLBACK_H
+
+#include <linux/firmware.h>
+#include <linux/device.h>
+
+#include "firmware.h"
+#include "sysfs.h"
+
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+int firmware_fallback_sysfs(struct firmware *fw, const char *name,
+			    struct device *device,
+			    u32 opt_flags,
+			    int ret);
+void kill_pending_fw_fallback_reqs(bool kill_all);
+
+void fw_fallback_set_cache_timeout(void);
+void fw_fallback_set_default_timeout(void);
+
+#else /* CONFIG_FW_LOADER_USER_HELPER */
+static inline int firmware_fallback_sysfs(struct firmware *fw, const char *name,
+					  struct device *device,
+					  u32 opt_flags,
+					  int ret)
+{
+	/* Keep carrying over the same error */
+	return ret;
+}
+
+static inline void kill_pending_fw_fallback_reqs(bool kill_all) { }
+static inline void fw_fallback_set_cache_timeout(void) { }
+static inline void fw_fallback_set_default_timeout(void) { }
+#endif /* CONFIG_FW_LOADER_USER_HELPER */
+
+#ifdef CONFIG_EFI_EMBEDDED_FIRMWARE
+int firmware_fallback_platform(struct fw_priv *fw_priv);
+#else
+static inline int firmware_fallback_platform(struct fw_priv *fw_priv)
+{
+	return -ENOENT;
+}
+#endif
+
+#endif /* __FIRMWARE_FALLBACK_H */

linux-7.2.3/drivers/base/firmware_loader/fallback_platform.c

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/efi_embedded_fw.h>
+#include <linux/property.h>
+#include <linux/security.h>
+#include <linux/vmalloc.h>
+
+#include "fallback.h"
+#include "firmware.h"
+
+int firmware_fallback_platform(struct fw_priv *fw_priv)
+{
+	const u8 *data;
+	size_t size;
+	int rc;
+
+	if (!(fw_priv->opt_flags & FW_OPT_FALLBACK_PLATFORM))
+		return -ENOENT;
+
+	rc = security_kernel_load_data(LOADING_FIRMWARE, true);
+	if (rc)
+		return rc;
+
+	rc = efi_get_embedded_fw(fw_priv->fw_name, &data, &size);
+	if (rc)
+		return rc; /* rc == -ENOENT when the fw was not found */
+
+	if (fw_priv->data && size > fw_priv->allocated_size)
+		return -ENOMEM;
+
+	rc = security_kernel_post_load_data((u8 *)data, size, LOADING_FIRMWARE,
+						"platform");
+	if (rc)
+		return rc;
+
+	if (!fw_priv->data)
+		fw_priv->data = vmalloc(size);
+	if (!fw_priv->data)
+		return -ENOMEM;
+
+	memcpy(fw_priv->data, data, size);
+	fw_priv->size = size;
+	fw_state_done(fw_priv);
+	return 0;
+}

linux-7.2.3/drivers/base/firmware_loader/fallback_table.c

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/kconfig.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/security.h>
+#include <linux/highmem.h>
+#include <linux/umh.h>
+#include <linux/sysctl.h>
+
+#include "fallback.h"
+#include "firmware.h"
+
+/*
+ * firmware fallback configuration table
+ */
+
+struct firmware_fallback_config fw_fallback_config = {
+	.force_sysfs_fallback = IS_ENABLED(CONFIG_FW_LOADER_USER_HELPER_FALLBACK),
+	.loading_timeout = 60,
+	.old_timeout = 60,
+};
+EXPORT_SYMBOL_NS_GPL(fw_fallback_config, "FIRMWARE_LOADER_PRIVATE");
+
+#ifdef CONFIG_SYSCTL
+static const struct ctl_table firmware_config_table[] = {
+	{
+		.procname	= "force_sysfs_fallback",
+		.data		= &fw_fallback_config.force_sysfs_fallback,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "ignore_sysfs_fallback",
+		.data		= &fw_fallback_config.ignore_sysfs_fallback,
+		.maxlen         = sizeof(unsigned int),
+		.mode           = 0644,
+		.proc_handler   = proc_douintvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+};
+
+static struct ctl_table_header *firmware_config_sysct_table_header;
+int register_firmware_config_sysctl(void)
+{
+	firmware_config_sysct_table_header =
+		register_sysctl("kernel/firmware_config",
+				firmware_config_table);
+	if (!firmware_config_sysct_table_header)
+		return -ENOMEM;
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(register_firmware_config_sysctl, "FIRMWARE_LOADER_PRIVATE");
+
+void unregister_firmware_config_sysctl(void)
+{
+	unregister_sysctl_table(firmware_config_sysct_table_header);
+	firmware_config_sysct_table_header = NULL;
+}
+EXPORT_SYMBOL_NS_GPL(unregister_firmware_config_sysctl, "FIRMWARE_LOADER_PRIVATE");
+
+#endif /* CONFIG_SYSCTL */

linux-7.2.3/drivers/base/firmware_loader/firmware.h

@@ -0,0 +1,198 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __FIRMWARE_LOADER_H
+#define __FIRMWARE_LOADER_H
+
+#include <linux/bitops.h>
+#include <linux/firmware.h>
+#include <linux/types.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/completion.h>
+
+/**
+ * enum fw_opt - options to control firmware loading behaviour
+ *
+ * @FW_OPT_UEVENT: Enables the fallback mechanism to send a kobject uevent
+ *	when the firmware is not found. Userspace is in charge to load the
+ *	firmware using the sysfs loading facility.
+ * @FW_OPT_NOWAIT: Used to describe the firmware request is asynchronous.
+ * @FW_OPT_USERHELPER: Enable the fallback mechanism, in case the direct
+ *	filesystem lookup fails at finding the firmware.  For details refer to
+ *	firmware_fallback_sysfs().
+ * @FW_OPT_NO_WARN: Quiet, avoid printing warning messages.
+ * @FW_OPT_NOCACHE: Disables firmware caching. Firmware caching is used to
+ *	cache the firmware upon suspend, so that upon resume races against the
+ *	firmware file lookup on storage is avoided. Used for calls where the
+ *	file may be too big, or where the driver takes charge of its own
+ *	firmware caching mechanism.
+ * @FW_OPT_NOFALLBACK_SYSFS: Disable the sysfs fallback mechanism. Takes
+ *	precedence over &FW_OPT_UEVENT and &FW_OPT_USERHELPER.
+ * @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
+ *	the platform's main firmware. If both this fallback and the sysfs
+ *      fallback are enabled, then this fallback will be tried first.
+ * @FW_OPT_PARTIAL: Allow partial read of firmware instead of needing to read
+ *	entire file.
+ */
+enum fw_opt {
+	FW_OPT_UEVENT			= BIT(0),
+	FW_OPT_NOWAIT			= BIT(1),
+	FW_OPT_USERHELPER		= BIT(2),
+	FW_OPT_NO_WARN			= BIT(3),
+	FW_OPT_NOCACHE			= BIT(4),
+	FW_OPT_NOFALLBACK_SYSFS		= BIT(5),
+	FW_OPT_FALLBACK_PLATFORM	= BIT(6),
+	FW_OPT_PARTIAL			= BIT(7),
+};
+
+enum fw_status {
+	FW_STATUS_UNKNOWN,
+	FW_STATUS_LOADING,
+	FW_STATUS_DONE,
+	FW_STATUS_ABORTED,
+};
+
+/*
+ * Concurrent request_firmware() for the same firmware need to be
+ * serialized.  struct fw_state is simple state machine which hold the
+ * state of the firmware loading.
+ */
+struct fw_state {
+	struct completion completion;
+	enum fw_status status;
+};
+
+struct fw_priv {
+	struct kref ref;
+	struct list_head list;
+	struct firmware_cache *fwc;
+	struct fw_state fw_st;
+	void *data;
+	size_t size;
+	size_t allocated_size;
+	size_t offset;
+	u32 opt_flags;
+#ifdef CONFIG_FW_LOADER_PAGED_BUF
+	bool is_paged_buf;
+	struct page **pages;
+	int nr_pages;
+	int page_array_size;
+#endif
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	bool need_uevent;
+	struct list_head pending_list;
+#endif
+	const char *fw_name;
+};
+
+extern struct mutex fw_lock;
+extern struct firmware_cache fw_cache;
+extern bool fw_load_abort_all;
+
+static inline bool __fw_state_check(struct fw_priv *fw_priv,
+				    enum fw_status status)
+{
+	struct fw_state *fw_st = &fw_priv->fw_st;
+
+	return fw_st->status == status;
+}
+
+static inline int __fw_state_wait_common(struct fw_priv *fw_priv, long timeout)
+{
+	struct fw_state *fw_st = &fw_priv->fw_st;
+	long ret;
+
+	ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout);
+	if (ret != 0 && fw_st->status == FW_STATUS_ABORTED)
+		return -ENOENT;
+	if (!ret)
+		return -ETIMEDOUT;
+
+	return ret < 0 ? ret : 0;
+}
+
+static inline void __fw_state_set(struct fw_priv *fw_priv,
+				  enum fw_status status)
+{
+	struct fw_state *fw_st = &fw_priv->fw_st;
+
+	WRITE_ONCE(fw_st->status, status);
+
+	if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) {
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+		/*
+		 * Doing this here ensures that the fw_priv is deleted from
+		 * the pending list in all abort/done paths.
+		 */
+		list_del_init(&fw_priv->pending_list);
+#endif
+		complete_all(&fw_st->completion);
+	}
+}
+
+static inline void fw_state_aborted(struct fw_priv *fw_priv)
+{
+	__fw_state_set(fw_priv, FW_STATUS_ABORTED);
+}
+
+static inline bool fw_state_is_aborted(struct fw_priv *fw_priv)
+{
+	return __fw_state_check(fw_priv, FW_STATUS_ABORTED);
+}
+
+static inline void fw_state_start(struct fw_priv *fw_priv)
+{
+	__fw_state_set(fw_priv, FW_STATUS_LOADING);
+}
+
+static inline void fw_state_done(struct fw_priv *fw_priv)
+{
+	__fw_state_set(fw_priv, FW_STATUS_DONE);
+}
+
+static inline bool fw_state_is_done(struct fw_priv *fw_priv)
+{
+	return __fw_state_check(fw_priv, FW_STATUS_DONE);
+}
+
+static inline bool fw_state_is_loading(struct fw_priv *fw_priv)
+{
+	return __fw_state_check(fw_priv, FW_STATUS_LOADING);
+}
+
+int alloc_lookup_fw_priv(const char *fw_name, struct firmware_cache *fwc,
+			 struct fw_priv **fw_priv, void *dbuf, size_t size,
+			 size_t offset, u32 opt_flags);
+int assign_fw(struct firmware *fw, struct device *device);
+void free_fw_priv(struct fw_priv *fw_priv);
+void fw_state_init(struct fw_priv *fw_priv);
+
+#ifdef CONFIG_FW_LOADER
+bool firmware_is_builtin(const struct firmware *fw);
+bool firmware_request_builtin_buf(struct firmware *fw, const char *name,
+				  void *buf, size_t size);
+#else /* module case */
+static inline bool firmware_is_builtin(const struct firmware *fw)
+{
+	return false;
+}
+static inline bool firmware_request_builtin_buf(struct firmware *fw,
+						const char *name,
+						void *buf, size_t size)
+{
+	return false;
+}
+#endif
+
+#ifdef CONFIG_FW_LOADER_PAGED_BUF
+void fw_free_paged_buf(struct fw_priv *fw_priv);
+int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
+int fw_map_paged_buf(struct fw_priv *fw_priv);
+bool fw_is_paged_buf(struct fw_priv *fw_priv);
+#else
+static inline void fw_free_paged_buf(struct fw_priv *fw_priv) {}
+static inline int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed) { return -ENXIO; }
+static inline int fw_map_paged_buf(struct fw_priv *fw_priv) { return -ENXIO; }
+static inline bool fw_is_paged_buf(struct fw_priv *fw_priv) { return false; }
+#endif
+
+#endif /* __FIRMWARE_LOADER_H */

linux-7.2.3/drivers/base/firmware_loader/sysfs.c

@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "sysfs.h"
+
+/*
+ * sysfs support for firmware loader
+ */
+
+void __fw_load_abort(struct fw_priv *fw_priv)
+{
+	/*
+	 * There is a small window in which user can write to 'loading'
+	 * between loading done/aborted and disappearance of 'loading'
+	 */
+	if (fw_state_is_aborted(fw_priv) || fw_state_is_done(fw_priv))
+		return;
+
+	fw_state_aborted(fw_priv);
+}
+
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+static ssize_t timeout_show(const struct class *class, const struct class_attribute *attr,
+			    char *buf)
+{
+	return sysfs_emit(buf, "%d\n", __firmware_loading_timeout());
+}
+
+/**
+ * timeout_store() - set number of seconds to wait for firmware
+ * @class: device class pointer
+ * @attr: device attribute pointer
+ * @buf: buffer to scan for timeout value
+ * @count: number of bytes in @buf
+ *
+ *	Sets the number of seconds to wait for the firmware.  Once
+ *	this expires an error will be returned to the driver and no
+ *	firmware will be provided.
+ *
+ *	Note: zero means 'wait forever'.
+ **/
+static ssize_t timeout_store(const struct class *class, const struct class_attribute *attr,
+			     const char *buf, size_t count)
+{
+	int tmp_loading_timeout;
+
+	if (kstrtoint(buf, 10, &tmp_loading_timeout))
+		return -EINVAL;
+
+	if (tmp_loading_timeout < 0)
+		tmp_loading_timeout = 0;
+
+	__fw_fallback_set_timeout(tmp_loading_timeout);
+
+	return count;
+}
+static CLASS_ATTR_RW(timeout);
+
+static struct attribute *firmware_class_attrs[] = {
+	&class_attr_timeout.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(firmware_class);
+
+static int do_firmware_uevent(const struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
+{
+	if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
+		return -ENOMEM;
+	if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
+		return -ENOMEM;
+	if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int firmware_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	const struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+	int err = 0;
+
+	mutex_lock(&fw_lock);
+	if (fw_sysfs->fw_priv)
+		err = do_firmware_uevent(fw_sysfs, env);
+	mutex_unlock(&fw_lock);
+	return err;
+}
+#endif /* CONFIG_FW_LOADER_USER_HELPER */
+
+static void fw_dev_release(struct device *dev)
+{
+	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+
+	if (fw_sysfs->fw_upload_priv)
+		fw_upload_free(fw_sysfs);
+
+	kfree(fw_sysfs);
+}
+
+static struct class firmware_class = {
+	.name		= "firmware",
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	.class_groups	= firmware_class_groups,
+	.dev_uevent	= firmware_uevent,
+#endif
+	.dev_release	= fw_dev_release,
+};
+
+int register_sysfs_loader(void)
+{
+	int ret = class_register(&firmware_class);
+
+	if (ret != 0)
+		return ret;
+	return register_firmware_config_sysctl();
+}
+
+void unregister_sysfs_loader(void)
+{
+	unregister_firmware_config_sysctl();
+	class_unregister(&firmware_class);
+}
+
+static ssize_t firmware_loading_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+	int loading = 0;
+
+	mutex_lock(&fw_lock);
+	if (fw_sysfs->fw_priv)
+		loading = fw_state_is_loading(fw_sysfs->fw_priv);
+	mutex_unlock(&fw_lock);
+
+	return sysfs_emit(buf, "%d\n", loading);
+}
+
+/**
+ * firmware_loading_store() - set value in the 'loading' control file
+ * @dev: device pointer
+ * @attr: device attribute pointer
+ * @buf: buffer to scan for loading control value
+ * @count: number of bytes in @buf
+ *
+ *	The relevant values are:
+ *
+ *	 1: Start a load, discarding any previous partial load.
+ *	 0: Conclude the load and hand the data to the driver code.
+ *	-1: Conclude the load with an error and discard any written data.
+ **/
+static ssize_t firmware_loading_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+	struct fw_priv *fw_priv;
+	ssize_t written = count;
+	int loading;
+
+	if (kstrtoint(buf, 10, &loading))
+		return -EINVAL;
+
+	mutex_lock(&fw_lock);
+	fw_priv = fw_sysfs->fw_priv;
+	if (fw_state_is_aborted(fw_priv) || fw_state_is_done(fw_priv))
+		goto out;
+
+	switch (loading) {
+	case 1:
+		/* discarding any previous partial load */
+		fw_free_paged_buf(fw_priv);
+		fw_state_start(fw_priv);
+		break;
+	case 0:
+		if (fw_state_is_loading(fw_priv)) {
+			int rc;
+
+			/*
+			 * Several loading requests may be pending on
+			 * one same firmware buf, so let all requests
+			 * see the mapped 'buf->data' once the loading
+			 * is completed.
+			 */
+			rc = fw_map_paged_buf(fw_priv);
+			if (rc)
+				dev_err(dev, "%s: map pages failed\n",
+					__func__);
+			else
+				rc = security_kernel_post_load_data(fw_priv->data,
+								    fw_priv->size,
+								    LOADING_FIRMWARE,
+								    "blob");
+
+			/*
+			 * Same logic as fw_load_abort, only the DONE bit
+			 * is ignored and we set ABORT only on failure.
+			 */
+			if (rc) {
+				fw_state_aborted(fw_priv);
+				written = rc;
+			} else {
+				fw_state_done(fw_priv);
+
+				/*
+				 * If this is a user-initiated firmware upload
+				 * then start the upload in a worker thread now.
+				 */
+				rc = fw_upload_start(fw_sysfs);
+				if (rc)
+					written = rc;
+			}
+			break;
+		}
+		fallthrough;
+	default:
+		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
+		fallthrough;
+	case -1:
+		fw_load_abort(fw_sysfs);
+		if (fw_sysfs->fw_upload_priv)
+			fw_state_init(fw_sysfs->fw_priv);
+
+		break;
+	}
+out:
+	mutex_unlock(&fw_lock);
+	return written;
+}
+
+DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
+
+static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
+			     loff_t offset, size_t count, bool read)
+{
+	if (read)
+		memcpy(buffer, fw_priv->data + offset, count);
+	else
+		memcpy(fw_priv->data + offset, buffer, count);
+}
+
+static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
+			loff_t offset, size_t count, bool read)
+{
+	while (count) {
+		int page_nr = offset >> PAGE_SHIFT;
+		int page_ofs = offset & (PAGE_SIZE - 1);
+		int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
+
+		if (read)
+			memcpy_from_page(buffer, fw_priv->pages[page_nr],
+					 page_ofs, page_cnt);
+		else
+			memcpy_to_page(fw_priv->pages[page_nr], page_ofs,
+				       buffer, page_cnt);
+
+		buffer += page_cnt;
+		offset += page_cnt;
+		count -= page_cnt;
+	}
+}
+
+static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
+				  const struct bin_attribute *bin_attr,
+				  char *buffer, loff_t offset, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+	struct fw_priv *fw_priv;
+	ssize_t ret_count;
+
+	mutex_lock(&fw_lock);
+	fw_priv = fw_sysfs->fw_priv;
+	if (!fw_priv || fw_state_is_done(fw_priv)) {
+		ret_count = -ENODEV;
+		goto out;
+	}
+	if (offset > fw_priv->size) {
+		ret_count = 0;
+		goto out;
+	}
+	if (count > fw_priv->size - offset)
+		count = fw_priv->size - offset;
+
+	ret_count = count;
+
+	if (fw_priv->data)
+		firmware_rw_data(fw_priv, buffer, offset, count, true);
+	else
+		firmware_rw(fw_priv, buffer, offset, count, true);
+
+out:
+	mutex_unlock(&fw_lock);
+	return ret_count;
+}
+
+static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
+{
+	int err;
+
+	err = fw_grow_paged_buf(fw_sysfs->fw_priv,
+				PAGE_ALIGN(min_size) >> PAGE_SHIFT);
+	if (err)
+		fw_load_abort(fw_sysfs);
+	return err;
+}
+
+/**
+ * firmware_data_write() - write method for firmware
+ * @filp: open sysfs file
+ * @kobj: kobject for the device
+ * @bin_attr: bin_attr structure
+ * @buffer: buffer being written
+ * @offset: buffer offset for write in total data store area
+ * @count: buffer size
+ *
+ *	Data written to the 'data' attribute will be later handed to
+ *	the driver as a firmware image.
+ **/
+static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
+				   const struct bin_attribute *bin_attr,
+				   char *buffer, loff_t offset, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
+	struct fw_priv *fw_priv;
+	ssize_t retval;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	mutex_lock(&fw_lock);
+	fw_priv = fw_sysfs->fw_priv;
+	if (!fw_priv || fw_state_is_done(fw_priv)) {
+		retval = -ENODEV;
+		goto out;
+	}
+
+	if (fw_priv->data) {
+		if (offset + count > fw_priv->allocated_size) {
+			retval = -ENOMEM;
+			goto out;
+		}
+		firmware_rw_data(fw_priv, buffer, offset, count, false);
+		retval = count;
+	} else {
+		retval = fw_realloc_pages(fw_sysfs, offset + count);
+		if (retval)
+			goto out;
+
+		retval = count;
+		firmware_rw(fw_priv, buffer, offset, count, false);
+	}
+
+	fw_priv->size = max_t(size_t, offset + count, fw_priv->size);
+out:
+	mutex_unlock(&fw_lock);
+	return retval;
+}
+
+static const struct bin_attribute firmware_attr_data = {
+	.attr = { .name = "data", .mode = 0644 },
+	.size = 0,
+	.read = firmware_data_read,
+	.write = firmware_data_write,
+};
+
+static struct attribute *fw_dev_attrs[] = {
+	&dev_attr_loading.attr,
+#ifdef CONFIG_FW_UPLOAD
+	&dev_attr_cancel.attr,
+	&dev_attr_status.attr,
+	&dev_attr_error.attr,
+	&dev_attr_remaining_size.attr,
+#endif
+	NULL
+};
+
+static const struct bin_attribute *const fw_dev_bin_attrs[] = {
+	&firmware_attr_data,
+	NULL
+};
+
+static const struct attribute_group fw_dev_attr_group = {
+	.attrs = fw_dev_attrs,
+	.bin_attrs = fw_dev_bin_attrs,
+#ifdef CONFIG_FW_UPLOAD
+	.is_visible = fw_upload_is_visible,
+#endif
+};
+
+static const struct attribute_group *fw_dev_attr_groups[] = {
+	&fw_dev_attr_group,
+	NULL
+};
+
+struct fw_sysfs *
+fw_create_instance(struct firmware *firmware, const char *fw_name,
+		   struct device *device, u32 opt_flags)
+{
+	struct fw_sysfs *fw_sysfs;
+	struct device *f_dev;
+
+	fw_sysfs = kzalloc_obj(*fw_sysfs);
+	if (!fw_sysfs) {
+		fw_sysfs = ERR_PTR(-ENOMEM);
+		goto exit;
+	}
+
+	fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
+	fw_sysfs->fw = firmware;
+	f_dev = &fw_sysfs->dev;
+
+	device_initialize(f_dev);
+	dev_set_name(f_dev, "%s", fw_name);
+	f_dev->parent = device;
+	f_dev->class = &firmware_class;
+	f_dev->groups = fw_dev_attr_groups;
+exit:
+	return fw_sysfs;
+}

linux-7.2.3/drivers/base/firmware_loader/sysfs.h

@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __FIRMWARE_SYSFS_H
+#define __FIRMWARE_SYSFS_H
+
+#include <linux/device.h>
+
+#include "firmware.h"
+
+MODULE_IMPORT_NS("FIRMWARE_LOADER_PRIVATE");
+
+extern struct firmware_fallback_config fw_fallback_config;
+extern struct device_attribute dev_attr_loading;
+
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+/**
+ * struct firmware_fallback_config - firmware fallback configuration settings
+ *
+ * Helps describe and fine tune the fallback mechanism.
+ *
+ * @force_sysfs_fallback: force the sysfs fallback mechanism to be used
+ *	as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
+ *	Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
+ *	functionality on a kernel where that config entry has been disabled.
+ * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
+ *	This emulates the behaviour as if we had set the kernel
+ *	config CONFIG_FW_LOADER_USER_HELPER=n.
+ * @old_timeout: for internal use
+ * @loading_timeout: the timeout to wait for the fallback mechanism before
+ *	giving up, in seconds.
+ */
+struct firmware_fallback_config {
+	unsigned int force_sysfs_fallback;
+	unsigned int ignore_sysfs_fallback;
+	int old_timeout;
+	int loading_timeout;
+};
+
+/* These getters are vetted to use int properly */
+static inline int __firmware_loading_timeout(void)
+{
+	return fw_fallback_config.loading_timeout;
+}
+
+/* These setters are vetted to use int properly */
+static inline void __fw_fallback_set_timeout(int timeout)
+{
+	fw_fallback_config.loading_timeout = timeout;
+}
+#endif
+
+#ifdef CONFIG_FW_LOADER_SYSFS
+int register_sysfs_loader(void);
+void unregister_sysfs_loader(void);
+#if defined(CONFIG_FW_LOADER_USER_HELPER) && defined(CONFIG_SYSCTL)
+int register_firmware_config_sysctl(void);
+void unregister_firmware_config_sysctl(void);
+#else
+static inline int register_firmware_config_sysctl(void)
+{
+	return 0;
+}
+
+static inline void unregister_firmware_config_sysctl(void) { }
+#endif /* CONFIG_FW_LOADER_USER_HELPER && CONFIG_SYSCTL */
+#else /* CONFIG_FW_LOADER_SYSFS */
+static inline int register_sysfs_loader(void)
+{
+	return 0;
+}
+
+static inline void unregister_sysfs_loader(void)
+{
+}
+#endif /* CONFIG_FW_LOADER_SYSFS */
+
+struct fw_sysfs {
+	bool nowait;
+	struct device dev;
+	struct fw_priv *fw_priv;
+	struct firmware *fw;
+	void *fw_upload_priv;
+};
+#define to_fw_sysfs(__dev)	container_of_const(__dev, struct fw_sysfs, dev)
+
+void __fw_load_abort(struct fw_priv *fw_priv);
+
+static inline void fw_load_abort(struct fw_sysfs *fw_sysfs)
+{
+	struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+
+	__fw_load_abort(fw_priv);
+}
+
+struct fw_sysfs *
+fw_create_instance(struct firmware *firmware, const char *fw_name,
+		   struct device *device, u32 opt_flags);
+
+#ifdef CONFIG_FW_UPLOAD
+extern struct device_attribute dev_attr_status;
+extern struct device_attribute dev_attr_error;
+extern struct device_attribute dev_attr_cancel;
+extern struct device_attribute dev_attr_remaining_size;
+
+int fw_upload_start(struct fw_sysfs *fw_sysfs);
+void fw_upload_free(struct fw_sysfs *fw_sysfs);
+umode_t fw_upload_is_visible(struct kobject *kobj, struct attribute *attr, int n);
+#else
+static inline int fw_upload_start(struct fw_sysfs *fw_sysfs)
+{
+	return 0;
+}
+
+static inline void fw_upload_free(struct fw_sysfs *fw_sysfs)
+{
+}
+#endif
+
+#endif /* __FIRMWARE_SYSFS_H */

linux-7.2.3/drivers/base/firmware_loader/sysfs_upload.c

@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "sysfs_upload.h"
+
+/*
+ * Support for user-space to initiate a firmware upload to a device.
+ */
+
+static const char * const fw_upload_prog_str[] = {
+	[FW_UPLOAD_PROG_IDLE]	      = "idle",
+	[FW_UPLOAD_PROG_RECEIVING]    = "receiving",
+	[FW_UPLOAD_PROG_PREPARING]    = "preparing",
+	[FW_UPLOAD_PROG_TRANSFERRING] = "transferring",
+	[FW_UPLOAD_PROG_PROGRAMMING]  = "programming"
+};
+
+static const char * const fw_upload_err_str[] = {
+	[FW_UPLOAD_ERR_NONE]	     = "none",
+	[FW_UPLOAD_ERR_HW_ERROR]     = "hw-error",
+	[FW_UPLOAD_ERR_TIMEOUT]	     = "timeout",
+	[FW_UPLOAD_ERR_CANCELED]     = "user-abort",
+	[FW_UPLOAD_ERR_BUSY]	     = "device-busy",
+	[FW_UPLOAD_ERR_INVALID_SIZE] = "invalid-file-size",
+	[FW_UPLOAD_ERR_RW_ERROR]     = "read-write-error",
+	[FW_UPLOAD_ERR_WEAROUT]	     = "flash-wearout",
+	[FW_UPLOAD_ERR_FW_INVALID]   = "firmware-invalid",
+};
+
+static const char *fw_upload_progress(struct device *dev,
+				      enum fw_upload_prog prog)
+{
+	const char *status = "unknown-status";
+
+	if (prog < FW_UPLOAD_PROG_MAX)
+		status = fw_upload_prog_str[prog];
+	else
+		dev_err(dev, "Invalid status during secure update: %d\n", prog);
+
+	return status;
+}
+
+static const char *fw_upload_error(struct device *dev,
+				   enum fw_upload_err err_code)
+{
+	const char *error = "unknown-error";
+
+	if (err_code < FW_UPLOAD_ERR_MAX)
+		error = fw_upload_err_str[err_code];
+	else
+		dev_err(dev, "Invalid error code during secure update: %d\n",
+			err_code);
+
+	return error;
+}
+
+static ssize_t
+status_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct fw_upload_priv *fwlp = to_fw_sysfs(dev)->fw_upload_priv;
+
+	return sysfs_emit(buf, "%s\n", fw_upload_progress(dev, fwlp->progress));
+}
+DEVICE_ATTR_RO(status);
+
+static ssize_t
+error_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct fw_upload_priv *fwlp = to_fw_sysfs(dev)->fw_upload_priv;
+	int ret;
+
+	mutex_lock(&fwlp->lock);
+
+	if (fwlp->progress != FW_UPLOAD_PROG_IDLE)
+		ret = -EBUSY;
+	else if (!fwlp->err_code)
+		ret = 0;
+	else
+		ret = sysfs_emit(buf, "%s:%s\n",
+				 fw_upload_progress(dev, fwlp->err_progress),
+				 fw_upload_error(dev, fwlp->err_code));
+
+	mutex_unlock(&fwlp->lock);
+
+	return ret;
+}
+DEVICE_ATTR_RO(error);
+
+static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct fw_upload_priv *fwlp = to_fw_sysfs(dev)->fw_upload_priv;
+	int ret = count;
+	bool cancel;
+
+	if (kstrtobool(buf, &cancel) || !cancel)
+		return -EINVAL;
+
+	mutex_lock(&fwlp->lock);
+	if (fwlp->progress == FW_UPLOAD_PROG_IDLE) {
+		mutex_unlock(&fwlp->lock);
+		return -ENODEV;
+	}
+
+	fwlp->ops->cancel(fwlp->fw_upload);
+	mutex_unlock(&fwlp->lock);
+
+	return ret;
+}
+DEVICE_ATTR_WO(cancel);
+
+static ssize_t remaining_size_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct fw_upload_priv *fwlp = to_fw_sysfs(dev)->fw_upload_priv;
+
+	return sysfs_emit(buf, "%u\n", fwlp->remaining_size);
+}
+DEVICE_ATTR_RO(remaining_size);
+
+umode_t
+fw_upload_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+	static struct fw_sysfs *fw_sysfs;
+
+	fw_sysfs = to_fw_sysfs(kobj_to_dev(kobj));
+
+	if (fw_sysfs->fw_upload_priv || attr == &dev_attr_loading.attr)
+		return attr->mode;
+
+	return 0;
+}
+
+static void fw_upload_update_progress(struct fw_upload_priv *fwlp,
+				      enum fw_upload_prog new_progress)
+{
+	mutex_lock(&fwlp->lock);
+	fwlp->progress = new_progress;
+	mutex_unlock(&fwlp->lock);
+}
+
+static void fw_upload_set_error(struct fw_upload_priv *fwlp,
+				enum fw_upload_err err_code)
+{
+	mutex_lock(&fwlp->lock);
+	fwlp->err_progress = fwlp->progress;
+	fwlp->err_code = err_code;
+	mutex_unlock(&fwlp->lock);
+}
+
+static void fw_upload_prog_complete(struct fw_upload_priv *fwlp)
+{
+	mutex_lock(&fwlp->lock);
+	fwlp->progress = FW_UPLOAD_PROG_IDLE;
+	mutex_unlock(&fwlp->lock);
+}
+
+static void fw_upload_main(struct work_struct *work)
+{
+	struct fw_upload_priv *fwlp;
+	struct fw_sysfs *fw_sysfs;
+	u32 written = 0, offset = 0;
+	enum fw_upload_err ret;
+	struct device *fw_dev;
+	struct fw_upload *fwl;
+
+	fwlp = container_of(work, struct fw_upload_priv, work);
+	fwl = fwlp->fw_upload;
+	fw_sysfs = (struct fw_sysfs *)fwl->priv;
+	fw_dev = &fw_sysfs->dev;
+
+	fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_PREPARING);
+	ret = fwlp->ops->prepare(fwl, fwlp->data, fwlp->remaining_size);
+	if (ret != FW_UPLOAD_ERR_NONE) {
+		fw_upload_set_error(fwlp, ret);
+		goto putdev_exit;
+	}
+
+	fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_TRANSFERRING);
+	while (fwlp->remaining_size) {
+		ret = fwlp->ops->write(fwl, fwlp->data, offset,
+					fwlp->remaining_size, &written);
+		if (ret != FW_UPLOAD_ERR_NONE || !written) {
+			if (ret == FW_UPLOAD_ERR_NONE) {
+				dev_warn(fw_dev, "write-op wrote zero data\n");
+				ret = FW_UPLOAD_ERR_RW_ERROR;
+			}
+			fw_upload_set_error(fwlp, ret);
+			goto done;
+		}
+
+		fwlp->remaining_size -= written;
+		offset += written;
+	}
+
+	fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_PROGRAMMING);
+	ret = fwlp->ops->poll_complete(fwl);
+	if (ret != FW_UPLOAD_ERR_NONE)
+		fw_upload_set_error(fwlp, ret);
+
+done:
+	if (fwlp->ops->cleanup)
+		fwlp->ops->cleanup(fwl);
+
+putdev_exit:
+	put_device(fw_dev->parent);
+
+	/*
+	 * Note: fwlp->remaining_size is left unmodified here to provide
+	 * additional information on errors. It will be reinitialized when
+	 * the next firmeware upload begins.
+	 */
+	mutex_lock(&fw_lock);
+	fw_free_paged_buf(fw_sysfs->fw_priv);
+	fw_state_init(fw_sysfs->fw_priv);
+	mutex_unlock(&fw_lock);
+	fwlp->data = NULL;
+	fw_upload_prog_complete(fwlp);
+}
+
+/*
+ * Start a worker thread to upload data to the parent driver.
+ * Must be called with fw_lock held.
+ */
+int fw_upload_start(struct fw_sysfs *fw_sysfs)
+{
+	struct fw_priv *fw_priv = fw_sysfs->fw_priv;
+	struct device *fw_dev = &fw_sysfs->dev;
+	struct fw_upload_priv *fwlp;
+
+	if (!fw_sysfs->fw_upload_priv)
+		return 0;
+
+	if (!fw_priv->size) {
+		fw_free_paged_buf(fw_priv);
+		fw_state_init(fw_sysfs->fw_priv);
+		return 0;
+	}
+
+	fwlp = fw_sysfs->fw_upload_priv;
+	mutex_lock(&fwlp->lock);
+
+	/* Do not interfere with an on-going fw_upload */
+	if (fwlp->progress != FW_UPLOAD_PROG_IDLE) {
+		mutex_unlock(&fwlp->lock);
+		return -EBUSY;
+	}
+
+	get_device(fw_dev->parent); /* released in fw_upload_main */
+
+	fwlp->progress = FW_UPLOAD_PROG_RECEIVING;
+	fwlp->err_code = 0;
+	fwlp->remaining_size = fw_priv->size;
+	fwlp->data = fw_priv->data;
+
+	pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
+		 __func__, fw_priv->fw_name,
+		 fw_priv, fw_priv->data,
+		 (unsigned int)fw_priv->size);
+
+	queue_work(system_long_wq, &fwlp->work);
+	mutex_unlock(&fwlp->lock);
+
+	return 0;
+}
+
+void fw_upload_free(struct fw_sysfs *fw_sysfs)
+{
+	struct fw_upload_priv *fw_upload_priv = fw_sysfs->fw_upload_priv;
+
+	free_fw_priv(fw_sysfs->fw_priv);
+	kfree(fw_upload_priv->fw_upload);
+	kfree(fw_upload_priv);
+}
+
+/**
+ * firmware_upload_register() - register for the firmware upload sysfs API
+ * @module: kernel module of this device
+ * @parent: parent device instantiating firmware upload
+ * @name: firmware name to be associated with this device
+ * @ops: pointer to structure of firmware upload ops
+ * @dd_handle: pointer to parent driver private data
+ *
+ *	@name must be unique among all users of firmware upload. The firmware
+ *	sysfs files for this device will be found at /sys/class/firmware/@name.
+ *
+ *	Return: struct fw_upload pointer or ERR_PTR()
+ *
+ **/
+struct fw_upload *
+firmware_upload_register(struct module *module, struct device *parent,
+			 const char *name, const struct fw_upload_ops *ops,
+			 void *dd_handle)
+{
+	u32 opt_flags = FW_OPT_NOCACHE;
+	struct fw_upload *fw_upload;
+	struct fw_upload_priv *fw_upload_priv;
+	struct fw_sysfs *fw_sysfs;
+	struct fw_priv *fw_priv;
+	struct device *fw_dev;
+	int ret;
+
+	if (!name || name[0] == '\0')
+		return ERR_PTR(-EINVAL);
+
+	if (!ops || !ops->cancel || !ops->prepare ||
+	    !ops->write || !ops->poll_complete) {
+		dev_err(parent, "Attempt to register without all required ops\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!try_module_get(module))
+		return ERR_PTR(-EFAULT);
+
+	fw_upload = kzalloc_obj(*fw_upload);
+	if (!fw_upload) {
+		ret = -ENOMEM;
+		goto exit_module_put;
+	}
+
+	fw_upload_priv = kzalloc_obj(*fw_upload_priv);
+	if (!fw_upload_priv) {
+		ret = -ENOMEM;
+		goto free_fw_upload;
+	}
+
+	fw_upload_priv->fw_upload = fw_upload;
+	fw_upload_priv->ops = ops;
+	mutex_init(&fw_upload_priv->lock);
+	fw_upload_priv->module = module;
+	fw_upload_priv->name = name;
+	fw_upload_priv->err_code = 0;
+	fw_upload_priv->progress = FW_UPLOAD_PROG_IDLE;
+	INIT_WORK(&fw_upload_priv->work, fw_upload_main);
+	fw_upload->dd_handle = dd_handle;
+
+	fw_sysfs = fw_create_instance(NULL, name, parent, opt_flags);
+	if (IS_ERR(fw_sysfs)) {
+		ret = PTR_ERR(fw_sysfs);
+		goto free_fw_upload_priv;
+	}
+	fw_upload->priv = fw_sysfs;
+	fw_dev = &fw_sysfs->dev;
+
+	ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv,  NULL, 0, 0,
+				   FW_OPT_NOCACHE);
+	if (ret != 0) {
+		if (ret > 0)
+			ret = -EINVAL;
+		put_device(fw_dev);
+		goto free_fw_upload_priv;
+	}
+	fw_priv->is_paged_buf = true;
+	fw_sysfs->fw_priv = fw_priv;
+	fw_sysfs->fw_upload_priv = fw_upload_priv;
+
+	ret = device_add(fw_dev);
+	if (ret) {
+		dev_err(fw_dev, "%s: device_register failed\n", __func__);
+		put_device(fw_dev);
+		goto exit_module_put;
+	}
+
+	return fw_upload;
+
+free_fw_upload_priv:
+	kfree(fw_upload_priv);
+
+free_fw_upload:
+	kfree(fw_upload);
+
+exit_module_put:
+	module_put(module);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(firmware_upload_register);
+
+/**
+ * firmware_upload_unregister() - Unregister firmware upload interface
+ * @fw_upload: pointer to struct fw_upload
+ **/
+void firmware_upload_unregister(struct fw_upload *fw_upload)
+{
+	struct fw_sysfs *fw_sysfs = fw_upload->priv;
+	struct fw_upload_priv *fw_upload_priv = fw_sysfs->fw_upload_priv;
+	struct module *module = fw_upload_priv->module;
+
+	mutex_lock(&fw_upload_priv->lock);
+	if (fw_upload_priv->progress == FW_UPLOAD_PROG_IDLE) {
+		mutex_unlock(&fw_upload_priv->lock);
+		goto unregister;
+	}
+
+	fw_upload_priv->ops->cancel(fw_upload);
+	mutex_unlock(&fw_upload_priv->lock);
+
+	/* Ensure lower-level device-driver is finished */
+	flush_work(&fw_upload_priv->work);
+
+unregister:
+	device_unregister(&fw_sysfs->dev);
+	module_put(module);
+}
+EXPORT_SYMBOL_GPL(firmware_upload_unregister);

linux-7.2.3/drivers/base/firmware_loader/sysfs_upload.h

@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SYSFS_UPLOAD_H
+#define __SYSFS_UPLOAD_H
+
+#include <linux/device.h>
+
+#include "sysfs.h"
+
+/**
+ * enum fw_upload_prog - firmware upload progress codes
+ * @FW_UPLOAD_PROG_IDLE: there is no firmware upload in progress
+ * @FW_UPLOAD_PROG_RECEIVING: worker thread is receiving firmware data
+ * @FW_UPLOAD_PROG_PREPARING: target device is preparing for firmware upload
+ * @FW_UPLOAD_PROG_TRANSFERRING: data is being copied to the device
+ * @FW_UPLOAD_PROG_PROGRAMMING: device is performing the firmware update
+ * @FW_UPLOAD_PROG_MAX: Maximum progress code marker
+ */
+enum fw_upload_prog {
+	FW_UPLOAD_PROG_IDLE,
+	FW_UPLOAD_PROG_RECEIVING,
+	FW_UPLOAD_PROG_PREPARING,
+	FW_UPLOAD_PROG_TRANSFERRING,
+	FW_UPLOAD_PROG_PROGRAMMING,
+	FW_UPLOAD_PROG_MAX
+};
+
+struct fw_upload_priv {
+	struct fw_upload *fw_upload;
+	struct module *module;
+	const char *name;
+	const struct fw_upload_ops *ops;
+	struct mutex lock;		  /* protect data structure contents */
+	struct work_struct work;
+	const u8 *data;			  /* pointer to update data */
+	u32 remaining_size;		  /* size remaining to transfer */
+	enum fw_upload_prog progress;
+	enum fw_upload_prog err_progress; /* progress at time of failure */
+	enum fw_upload_err err_code;	  /* security manager error code */
+};
+
+#endif /* __SYSFS_UPLOAD_H */