// SPDX-License-Identifier: GPL-2.0 /* * file.c - part of debugfs, a tiny little debug file system * * Copyright (C) 2004 Greg Kroah-Hartman <[email protected]> * Copyright (C) 2004 IBM Inc. * * debugfs is for people to use instead of /proc or /sys. * See Documentation/filesystems/ for more details. */ #include <linux/module.h> #include <linux/fs.h> #include <linux/seq_file.h> #include <linux/pagemap.h> #include <linux/debugfs.h> #include <linux/io.h> #include <linux/slab.h> #include <linux/atomic.h> #include <linux/device.h> #include <linux/pm_runtime.h> #include <linux/poll.h> #include <linux/security.h> #include "internal.h" struct poll_table_struct; static ssize_t default_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { … } static ssize_t default_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { … } const struct file_operations debugfs_noop_file_operations = …; #define F_DENTRY(filp) … const struct file_operations *debugfs_real_fops(const struct file *filp) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_file_get - mark the beginning of file data access * @dentry: the dentry object whose data is being accessed. * * Up to a matching call to debugfs_file_put(), any successive call * into the file removing functions debugfs_remove() and * debugfs_remove_recursive() will block. Since associated private * file data may only get freed after a successful return of any of * the removal functions, you may safely access it after a successful * call to debugfs_file_get() without worrying about lifetime issues. * * If -%EIO is returned, the file has already been removed and thus, * it is not safe to access any of its data. If, on the other hand, * it is allowed to access the file data, zero is returned. */ int debugfs_file_get(struct dentry *dentry) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_file_put - mark the end of file data access * @dentry: the dentry object formerly passed to * debugfs_file_get(). * * Allow any ongoing concurrent call into debugfs_remove() or * debugfs_remove_recursive() blocked by a former call to * debugfs_file_get() to proceed and return to its caller. */ void debugfs_file_put(struct dentry *dentry) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_enter_cancellation - enter a debugfs cancellation * @file: the file being accessed * @cancellation: the cancellation object, the cancel callback * inside of it must be initialized * * When a debugfs file is removed it needs to wait for all active * operations to complete. However, the operation itself may need * to wait for hardware or completion of some asynchronous process * or similar. As such, it may need to be cancelled to avoid long * waits or even deadlocks. * * This function can be used inside a debugfs handler that may * need to be cancelled. As soon as this function is called, the * cancellation's 'cancel' callback may be called, at which point * the caller should proceed to call debugfs_leave_cancellation() * and leave the debugfs handler function as soon as possible. * Note that the 'cancel' callback is only ever called in the * context of some kind of debugfs_remove(). * * This function must be paired with debugfs_leave_cancellation(). */ void debugfs_enter_cancellation(struct file *file, struct debugfs_cancellation *cancellation) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_leave_cancellation - leave cancellation section * @file: the file being accessed * @cancellation: the cancellation previously registered with * debugfs_enter_cancellation() * * See the documentation of debugfs_enter_cancellation(). */ void debugfs_leave_cancellation(struct file *file, struct debugfs_cancellation *cancellation) { … } EXPORT_SYMBOL_GPL(…); /* * Only permit access to world-readable files when the kernel is locked down. * We also need to exclude any file that has ways to write or alter it as root * can bypass the permissions check. */ static int debugfs_locked_down(struct inode *inode, struct file *filp, const struct file_operations *real_fops) { … } static int open_proxy_open(struct inode *inode, struct file *filp) { … } const struct file_operations debugfs_open_proxy_file_operations = …; #define PROTO(args...) … #define ARGS(args...) … #define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) … FULL_PROXY_FUNC(llseek, loff_t, filp, PROTO(struct file *filp, loff_t offset, int whence), ARGS(filp, offset, whence)); FULL_PROXY_FUNC(read, ssize_t, filp, PROTO(struct file *filp, char __user *buf, size_t size, loff_t *ppos), ARGS(filp, buf, size, ppos)); FULL_PROXY_FUNC(write, ssize_t, filp, PROTO(struct file *filp, const char __user *buf, size_t size, loff_t *ppos), ARGS(filp, buf, size, ppos)); FULL_PROXY_FUNC(unlocked_ioctl, long, filp, PROTO(struct file *filp, unsigned int cmd, unsigned long arg), ARGS(filp, cmd, arg)); static __poll_t full_proxy_poll(struct file *filp, struct poll_table_struct *wait) { … } static int full_proxy_release(struct inode *inode, struct file *filp) { … } static void __full_proxy_fops_init(struct file_operations *proxy_fops, const struct file_operations *real_fops) { … } static int full_proxy_open(struct inode *inode, struct file *filp) { … } const struct file_operations debugfs_full_proxy_file_operations = …; ssize_t debugfs_attr_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { … } EXPORT_SYMBOL_GPL(…); static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf, size_t len, loff_t *ppos, bool is_signed) { … } ssize_t debugfs_attr_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos) { … } EXPORT_SYMBOL_GPL(…); ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf, size_t len, loff_t *ppos) { … } EXPORT_SYMBOL_GPL(…); static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode, struct dentry *parent, void *value, const struct file_operations *fops, const struct file_operations *fops_ro, const struct file_operations *fops_wo) { … } static int debugfs_u8_set(void *data, u64 val) { … } static int debugfs_u8_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /** * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent, u8 *value) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_u16_set(void *data, u64 val) { … } static int debugfs_u16_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /** * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent, u16 *value) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_u32_set(void *data, u64 val) { … } static int debugfs_u32_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /** * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent, u32 *value) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_u64_set(void *data, u64 val) { … } static int debugfs_u64_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /** * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent, u64 *value) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_ulong_set(void *data, u64 val) { … } static int debugfs_ulong_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /** * debugfs_create_ulong - create a debugfs file that is used to read and write * an unsigned long value. * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent, unsigned long *value) { … } EXPORT_SYMBOL_GPL(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /* * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value * * These functions are exactly the same as the above functions (but use a hex * output for the decimal challenged). For details look at the above unsigned * decimal functions. */ /** * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent, u8 *value) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent, u16 *value) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent, u32 *value) { … } EXPORT_SYMBOL_GPL(…); /** * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent, u64 *value) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_size_t_set(void *data, u64 val) { … } static int debugfs_size_t_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); /* %llu and %zu are more or less the same */ DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); /** * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ void debugfs_create_size_t(const char *name, umode_t mode, struct dentry *parent, size_t *value) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_atomic_t_set(void *data, u64 val) { … } static int debugfs_atomic_t_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(…); DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(…); DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(…); /** * debugfs_create_atomic_t - create a debugfs file that is used to read and * write an atomic_t value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. */ void debugfs_create_atomic_t(const char *name, umode_t mode, struct dentry *parent, atomic_t *value) { … } EXPORT_SYMBOL_GPL(…); ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { … } EXPORT_SYMBOL_GPL(…); ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { … } EXPORT_SYMBOL_GPL(…); static const struct file_operations fops_bool = …; static const struct file_operations fops_bool_ro = …; static const struct file_operations fops_bool_wo = …; /** * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent, bool *value) { … } EXPORT_SYMBOL_GPL(…); ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { … } EXPORT_SYMBOL_GPL(…); static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { … } static const struct file_operations fops_str = …; static const struct file_operations fops_str_ro = …; static const struct file_operations fops_str_wo = …; /** * debugfs_create_str - create a debugfs file that is used to read and write a string value * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write * from. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. */ void debugfs_create_str(const char *name, umode_t mode, struct dentry *parent, char **value) { … } static ssize_t read_file_blob(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { … } static ssize_t write_file_blob(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { … } static const struct file_operations fops_blob = …; /** * debugfs_create_blob - create a debugfs file that is used to read and write * a binary blob * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer * to the blob data and the size of the data. * * This function creates a file in debugfs with the given name that exports * @blob->data as a binary blob. If the @mode variable is so set it can be * read from and written to. * * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file is * to be removed (no automatic cleanup happens if your module is unloaded, * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be * returned. * * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will * be returned. */ struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob) { … } EXPORT_SYMBOL_GPL(…); static size_t u32_format_array(char *buf, size_t bufsize, u32 *array, int array_size) { … } static int u32_array_open(struct inode *inode, struct file *file) { … } static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { … } static int u32_array_release(struct inode *inode, struct file *file) { … } static const struct file_operations u32_array_fops = …; /** * debugfs_create_u32_array - create a debugfs file that is used to read u32 * array. * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have. * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @array: wrapper struct containing data pointer and size of the array. * * This function creates a file in debugfs with the given name that exports * @array as data. If the @mode variable is so set it can be read from. * Writing is not supported. Seek within the file is also not supported. * Once array is created its size can not be changed. */ void debugfs_create_u32_array(const char *name, umode_t mode, struct dentry *parent, struct debugfs_u32_array *array) { … } EXPORT_SYMBOL_GPL(…); #ifdef CONFIG_HAS_IOMEM /* * The regset32 stuff is used to print 32-bit registers using the * seq_file utilities. We offer printing a register set in an already-opened * sequential file or create a debugfs file that only prints a regset32. */ /** * debugfs_print_regs32 - use seq_print to describe a set of registers * @s: the seq_file structure being used to generate output * @regs: an array if struct debugfs_reg32 structures * @nregs: the length of the above array * @base: the base address to be used in reading the registers * @prefix: a string to be prefixed to every output line * * This function outputs a text block describing the current values of * some 32-bit hardware registers. It is meant to be used within debugfs * files based on seq_file that need to show registers, intermixed with other * information. The prefix argument may be used to specify a leading string, * because some peripherals have several blocks of identical registers, * for example configuration of dma channels */ void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs, int nregs, void __iomem *base, char *prefix) { … } EXPORT_SYMBOL_GPL(…); static int debugfs_regset32_show(struct seq_file *s, void *data) { … } DEFINE_SHOW_ATTRIBUTE(…); /** * debugfs_create_regset32 - create a debugfs file that returns register values * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @regset: a pointer to a struct debugfs_regset32, which contains a pointer * to an array of register definitions, the array size and the base * address where the register bank is to be found. * * This function creates a file in debugfs with the given name that reports * the names and values of a set of 32-bit registers. If the @mode variable * is so set it can be read from. Writing is not supported. */ void debugfs_create_regset32(const char *name, umode_t mode, struct dentry *parent, struct debugfs_regset32 *regset) { … } EXPORT_SYMBOL_GPL(…); #endif /* CONFIG_HAS_IOMEM */ struct debugfs_devm_entry { … }; static int debugfs_devm_entry_open(struct inode *inode, struct file *f) { … } static const struct file_operations debugfs_devm_entry_ops = …; /** * debugfs_create_devm_seqfile - create a debugfs file that is bound to device. * * @dev: device related to this debugfs file. * @name: name of the debugfs file. * @parent: a pointer to the parent dentry for this file. This should be a * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @read_fn: function pointer called to print the seq_file content. */ void debugfs_create_devm_seqfile(struct device *dev, const char *name, struct dentry *parent, int (*read_fn)(struct seq_file *s, void *data)) { … } EXPORT_SYMBOL_GPL(…);
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