linux/fs/debugfs/file.c
Johannes Berg f4acfcd4de debugfs: annotate debugfs handlers vs. removal with lockdep
When you take a lock in a debugfs handler but also try
to remove the debugfs file under that lock, things can
deadlock since the removal has to wait for all users
to finish.

Add lockdep annotations in debugfs_file_get()/_put()
to catch such issues.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2023-11-27 11:24:50 +01:00

1286 lines
39 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* file.c - part of debugfs, a tiny little debug file system
*
* Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
* 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)
{
return 0;
}
static ssize_t default_write_file(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
return count;
}
const struct file_operations debugfs_noop_file_operations = {
.read = default_read_file,
.write = default_write_file,
.open = simple_open,
.llseek = noop_llseek,
};
#define F_DENTRY(filp) ((filp)->f_path.dentry)
const struct file_operations *debugfs_real_fops(const struct file *filp)
{
struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
/*
* Urgh, we've been called w/o a protecting
* debugfs_file_get().
*/
WARN_ON(1);
return NULL;
}
return fsd->real_fops;
}
EXPORT_SYMBOL_GPL(debugfs_real_fops);
/**
* 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)
{
struct debugfs_fsdata *fsd;
void *d_fsd;
/*
* This could only happen if some debugfs user erroneously calls
* debugfs_file_get() on a dentry that isn't even a file, let
* them know about it.
*/
if (WARN_ON(!d_is_reg(dentry)))
return -EINVAL;
d_fsd = READ_ONCE(dentry->d_fsdata);
if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
fsd = d_fsd;
} else {
fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
if (!fsd)
return -ENOMEM;
fsd->real_fops = (void *)((unsigned long)d_fsd &
~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
refcount_set(&fsd->active_users, 1);
init_completion(&fsd->active_users_drained);
if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
kfree(fsd);
fsd = READ_ONCE(dentry->d_fsdata);
}
#ifdef CONFIG_LOCKDEP
fsd->lock_name = kasprintf(GFP_KERNEL, "debugfs:%pd", dentry);
lockdep_register_key(&fsd->key);
lockdep_init_map(&fsd->lockdep_map, fsd->lock_name ?: "debugfs",
&fsd->key, 0);
#endif
}
/*
* In case of a successful cmpxchg() above, this check is
* strictly necessary and must follow it, see the comment in
* __debugfs_remove_file().
* OTOH, if the cmpxchg() hasn't been executed or wasn't
* successful, this serves the purpose of not starving
* removers.
*/
if (d_unlinked(dentry))
return -EIO;
if (!refcount_inc_not_zero(&fsd->active_users))
return -EIO;
lock_map_acquire_read(&fsd->lockdep_map);
return 0;
}
EXPORT_SYMBOL_GPL(debugfs_file_get);
/**
* 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)
{
struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
lock_map_release(&fsd->lockdep_map);
if (refcount_dec_and_test(&fsd->active_users))
complete(&fsd->active_users_drained);
}
EXPORT_SYMBOL_GPL(debugfs_file_put);
/*
* 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)
{
if ((inode->i_mode & 07777 & ~0444) == 0 &&
!(filp->f_mode & FMODE_WRITE) &&
!real_fops->unlocked_ioctl &&
!real_fops->compat_ioctl &&
!real_fops->mmap)
return 0;
if (security_locked_down(LOCKDOWN_DEBUGFS))
return -EPERM;
return 0;
}
static int open_proxy_open(struct inode *inode, struct file *filp)
{
struct dentry *dentry = F_DENTRY(filp);
const struct file_operations *real_fops = NULL;
int r;
r = debugfs_file_get(dentry);
if (r)
return r == -EIO ? -ENOENT : r;
real_fops = debugfs_real_fops(filp);
r = debugfs_locked_down(inode, filp, real_fops);
if (r)
goto out;
if (!fops_get(real_fops)) {
#ifdef CONFIG_MODULES
if (real_fops->owner &&
real_fops->owner->state == MODULE_STATE_GOING) {
r = -ENXIO;
goto out;
}
#endif
/* Huh? Module did not clean up after itself at exit? */
WARN(1, "debugfs file owner did not clean up at exit: %pd",
dentry);
r = -ENXIO;
goto out;
}
replace_fops(filp, real_fops);
if (real_fops->open)
r = real_fops->open(inode, filp);
out:
debugfs_file_put(dentry);
return r;
}
const struct file_operations debugfs_open_proxy_file_operations = {
.open = open_proxy_open,
};
#define PROTO(args...) args
#define ARGS(args...) args
#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
static ret_type full_proxy_ ## name(proto) \
{ \
struct dentry *dentry = F_DENTRY(filp); \
const struct file_operations *real_fops; \
ret_type r; \
\
r = debugfs_file_get(dentry); \
if (unlikely(r)) \
return r; \
real_fops = debugfs_real_fops(filp); \
r = real_fops->name(args); \
debugfs_file_put(dentry); \
return r; \
}
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)
{
struct dentry *dentry = F_DENTRY(filp);
__poll_t r = 0;
const struct file_operations *real_fops;
if (debugfs_file_get(dentry))
return EPOLLHUP;
real_fops = debugfs_real_fops(filp);
r = real_fops->poll(filp, wait);
debugfs_file_put(dentry);
return r;
}
static int full_proxy_release(struct inode *inode, struct file *filp)
{
const struct dentry *dentry = F_DENTRY(filp);
const struct file_operations *real_fops = debugfs_real_fops(filp);
const struct file_operations *proxy_fops = filp->f_op;
int r = 0;
/*
* We must not protect this against removal races here: the
* original releaser should be called unconditionally in order
* not to leak any resources. Releasers must not assume that
* ->i_private is still being meaningful here.
*/
if (real_fops->release)
r = real_fops->release(inode, filp);
replace_fops(filp, d_inode(dentry)->i_fop);
kfree(proxy_fops);
fops_put(real_fops);
return r;
}
static void __full_proxy_fops_init(struct file_operations *proxy_fops,
const struct file_operations *real_fops)
{
proxy_fops->release = full_proxy_release;
if (real_fops->llseek)
proxy_fops->llseek = full_proxy_llseek;
if (real_fops->read)
proxy_fops->read = full_proxy_read;
if (real_fops->write)
proxy_fops->write = full_proxy_write;
if (real_fops->poll)
proxy_fops->poll = full_proxy_poll;
if (real_fops->unlocked_ioctl)
proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
}
static int full_proxy_open(struct inode *inode, struct file *filp)
{
struct dentry *dentry = F_DENTRY(filp);
const struct file_operations *real_fops = NULL;
struct file_operations *proxy_fops = NULL;
int r;
r = debugfs_file_get(dentry);
if (r)
return r == -EIO ? -ENOENT : r;
real_fops = debugfs_real_fops(filp);
r = debugfs_locked_down(inode, filp, real_fops);
if (r)
goto out;
if (!fops_get(real_fops)) {
#ifdef CONFIG_MODULES
if (real_fops->owner &&
real_fops->owner->state == MODULE_STATE_GOING) {
r = -ENXIO;
goto out;
}
#endif
/* Huh? Module did not cleanup after itself at exit? */
WARN(1, "debugfs file owner did not clean up at exit: %pd",
dentry);
r = -ENXIO;
goto out;
}
proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
if (!proxy_fops) {
r = -ENOMEM;
goto free_proxy;
}
__full_proxy_fops_init(proxy_fops, real_fops);
replace_fops(filp, proxy_fops);
if (real_fops->open) {
r = real_fops->open(inode, filp);
if (r) {
replace_fops(filp, d_inode(dentry)->i_fop);
goto free_proxy;
} else if (filp->f_op != proxy_fops) {
/* No protection against file removal anymore. */
WARN(1, "debugfs file owner replaced proxy fops: %pd",
dentry);
goto free_proxy;
}
}
goto out;
free_proxy:
kfree(proxy_fops);
fops_put(real_fops);
out:
debugfs_file_put(dentry);
return r;
}
const struct file_operations debugfs_full_proxy_file_operations = {
.open = full_proxy_open,
};
ssize_t debugfs_attr_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
struct dentry *dentry = F_DENTRY(file);
ssize_t ret;
ret = debugfs_file_get(dentry);
if (unlikely(ret))
return ret;
ret = simple_attr_read(file, buf, len, ppos);
debugfs_file_put(dentry);
return ret;
}
EXPORT_SYMBOL_GPL(debugfs_attr_read);
static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf,
size_t len, loff_t *ppos, bool is_signed)
{
struct dentry *dentry = F_DENTRY(file);
ssize_t ret;
ret = debugfs_file_get(dentry);
if (unlikely(ret))
return ret;
if (is_signed)
ret = simple_attr_write_signed(file, buf, len, ppos);
else
ret = simple_attr_write(file, buf, len, ppos);
debugfs_file_put(dentry);
return ret;
}
ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
return debugfs_attr_write_xsigned(file, buf, len, ppos, false);
}
EXPORT_SYMBOL_GPL(debugfs_attr_write);
ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
return debugfs_attr_write_xsigned(file, buf, len, ppos, true);
}
EXPORT_SYMBOL_GPL(debugfs_attr_write_signed);
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)
{
/* if there are no write bits set, make read only */
if (!(mode & S_IWUGO))
return debugfs_create_file_unsafe(name, mode, parent, value,
fops_ro);
/* if there are no read bits set, make write only */
if (!(mode & S_IRUGO))
return debugfs_create_file_unsafe(name, mode, parent, value,
fops_wo);
return debugfs_create_file_unsafe(name, mode, parent, value, fops);
}
static int debugfs_u8_set(void *data, u64 val)
{
*(u8 *)data = val;
return 0;
}
static int debugfs_u8_get(void *data, u64 *val)
{
*val = *(u8 *)data;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
&fops_u8_ro, &fops_u8_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u8);
static int debugfs_u16_set(void *data, u64 val)
{
*(u16 *)data = val;
return 0;
}
static int debugfs_u16_get(void *data, u64 *val)
{
*val = *(u16 *)data;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
&fops_u16_ro, &fops_u16_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u16);
static int debugfs_u32_set(void *data, u64 val)
{
*(u32 *)data = val;
return 0;
}
static int debugfs_u32_get(void *data, u64 *val)
{
*val = *(u32 *)data;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
&fops_u32_ro, &fops_u32_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32);
static int debugfs_u64_set(void *data, u64 val)
{
*(u64 *)data = val;
return 0;
}
static int debugfs_u64_get(void *data, u64 *val)
{
*val = *(u64 *)data;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
&fops_u64_ro, &fops_u64_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u64);
static int debugfs_ulong_set(void *data, u64 val)
{
*(unsigned long *)data = val;
return 0;
}
static int debugfs_ulong_get(void *data, u64 *val)
{
*val = *(unsigned long *)data;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
"%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_ulong,
&fops_ulong_ro, &fops_ulong_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_ulong);
DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
"0x%04llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
"0x%08llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
"0x%016llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
/*
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
&fops_x8_ro, &fops_x8_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
&fops_x16_ro, &fops_x16_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
&fops_x32_ro, &fops_x32_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
&fops_x64_ro, &fops_x64_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x64);
static int debugfs_size_t_set(void *data, u64 val)
{
*(size_t *)data = val;
return 0;
}
static int debugfs_size_t_get(void *data, u64 *val)
{
*val = *(size_t *)data;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
"%llu\n"); /* %llu and %zu are more or less the same */
DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
&fops_size_t_ro, &fops_size_t_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_size_t);
static int debugfs_atomic_t_set(void *data, u64 val)
{
atomic_set((atomic_t *)data, val);
return 0;
}
static int debugfs_atomic_t_get(void *data, u64 *val)
{
*val = atomic_read((atomic_t *)data);
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get,
debugfs_atomic_t_set, "%lld\n");
DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
"%lld\n");
DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
"%lld\n");
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
&fops_atomic_t_ro, &fops_atomic_t_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[2];
bool val;
int r;
struct dentry *dentry = F_DENTRY(file);
r = debugfs_file_get(dentry);
if (unlikely(r))
return r;
val = *(bool *)file->private_data;
debugfs_file_put(dentry);
if (val)
buf[0] = 'Y';
else
buf[0] = 'N';
buf[1] = '\n';
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}
EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
bool bv;
int r;
bool *val = file->private_data;
struct dentry *dentry = F_DENTRY(file);
r = kstrtobool_from_user(user_buf, count, &bv);
if (!r) {
r = debugfs_file_get(dentry);
if (unlikely(r))
return r;
*val = bv;
debugfs_file_put(dentry);
}
return count;
}
EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
static const struct file_operations fops_bool = {
.read = debugfs_read_file_bool,
.write = debugfs_write_file_bool,
.open = simple_open,
.llseek = default_llseek,
};
static const struct file_operations fops_bool_ro = {
.read = debugfs_read_file_bool,
.open = simple_open,
.llseek = default_llseek,
};
static const struct file_operations fops_bool_wo = {
.write = debugfs_write_file_bool,
.open = simple_open,
.llseek = default_llseek,
};
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
&fops_bool_ro, &fops_bool_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_bool);
ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct dentry *dentry = F_DENTRY(file);
char *str, *copy = NULL;
int copy_len, len;
ssize_t ret;
ret = debugfs_file_get(dentry);
if (unlikely(ret))
return ret;
str = *(char **)file->private_data;
len = strlen(str) + 1;
copy = kmalloc(len, GFP_KERNEL);
if (!copy) {
debugfs_file_put(dentry);
return -ENOMEM;
}
copy_len = strscpy(copy, str, len);
debugfs_file_put(dentry);
if (copy_len < 0) {
kfree(copy);
return copy_len;
}
copy[copy_len] = '\n';
ret = simple_read_from_buffer(user_buf, count, ppos, copy, len);
kfree(copy);
return ret;
}
EXPORT_SYMBOL_GPL(debugfs_create_str);
static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct dentry *dentry = F_DENTRY(file);
char *old, *new = NULL;
int pos = *ppos;
int r;
r = debugfs_file_get(dentry);
if (unlikely(r))
return r;
old = *(char **)file->private_data;
/* only allow strict concatenation */
r = -EINVAL;
if (pos && pos != strlen(old))
goto error;
r = -E2BIG;
if (pos + count + 1 > PAGE_SIZE)
goto error;
r = -ENOMEM;
new = kmalloc(pos + count + 1, GFP_KERNEL);
if (!new)
goto error;
if (pos)
memcpy(new, old, pos);
r = -EFAULT;
if (copy_from_user(new + pos, user_buf, count))
goto error;
new[pos + count] = '\0';
strim(new);
rcu_assign_pointer(*(char **)file->private_data, new);
synchronize_rcu();
kfree(old);
debugfs_file_put(dentry);
return count;
error:
kfree(new);
debugfs_file_put(dentry);
return r;
}
static const struct file_operations fops_str = {
.read = debugfs_read_file_str,
.write = debugfs_write_file_str,
.open = simple_open,
.llseek = default_llseek,
};
static const struct file_operations fops_str_ro = {
.read = debugfs_read_file_str,
.open = simple_open,
.llseek = default_llseek,
};
static const struct file_operations fops_str_wo = {
.write = debugfs_write_file_str,
.open = simple_open,
.llseek = default_llseek,
};
/**
* 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)
{
debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str,
&fops_str_ro, &fops_str_wo);
}
static ssize_t read_file_blob(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct debugfs_blob_wrapper *blob = file->private_data;
struct dentry *dentry = F_DENTRY(file);
ssize_t r;
r = debugfs_file_get(dentry);
if (unlikely(r))
return r;
r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
blob->size);
debugfs_file_put(dentry);
return r;
}
static const struct file_operations fops_blob = {
.read = read_file_blob,
.open = simple_open,
.llseek = default_llseek,
};
/**
* debugfs_create_blob - create a debugfs file that is used to read a binary blob
* @name: a pointer to a string containing the name of the file to create.
* @mode: the read permission that the file should have (other permissions are
* masked out)
* @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. Writing is not supported.
*
* 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)
{
return debugfs_create_file_unsafe(name, mode & 0444, parent, blob, &fops_blob);
}
EXPORT_SYMBOL_GPL(debugfs_create_blob);
static size_t u32_format_array(char *buf, size_t bufsize,
u32 *array, int array_size)
{
size_t ret = 0;
while (--array_size >= 0) {
size_t len;
char term = array_size ? ' ' : '\n';
len = snprintf(buf, bufsize, "%u%c", *array++, term);
ret += len;
buf += len;
bufsize -= len;
}
return ret;
}
static int u32_array_open(struct inode *inode, struct file *file)
{
struct debugfs_u32_array *data = inode->i_private;
int size, elements = data->n_elements;
char *buf;
/*
* Max size:
* - 10 digits + ' '/'\n' = 11 bytes per number
* - terminating NUL character
*/
size = elements*11;
buf = kmalloc(size+1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
buf[size] = 0;
file->private_data = buf;
u32_format_array(buf, size, data->array, data->n_elements);
return nonseekable_open(inode, file);
}
static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
loff_t *ppos)
{
size_t size = strlen(file->private_data);
return simple_read_from_buffer(buf, len, ppos,
file->private_data, size);
}
static int u32_array_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
}
static const struct file_operations u32_array_fops = {
.owner = THIS_MODULE,
.open = u32_array_open,
.release = u32_array_release,
.read = u32_array_read,
.llseek = no_llseek,
};
/**
* 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)
{
debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
#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)
{
int i;
for (i = 0; i < nregs; i++, regs++) {
if (prefix)
seq_printf(s, "%s", prefix);
seq_printf(s, "%s = 0x%08x\n", regs->name,
readl(base + regs->offset));
if (seq_has_overflowed(s))
break;
}
}
EXPORT_SYMBOL_GPL(debugfs_print_regs32);
static int debugfs_regset32_show(struct seq_file *s, void *data)
{
struct debugfs_regset32 *regset = s->private;
if (regset->dev)
pm_runtime_get_sync(regset->dev);
debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
if (regset->dev)
pm_runtime_put(regset->dev);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
/**
* 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)
{
debugfs_create_file(name, mode, parent, regset, &debugfs_regset32_fops);
}
EXPORT_SYMBOL_GPL(debugfs_create_regset32);
#endif /* CONFIG_HAS_IOMEM */
struct debugfs_devm_entry {
int (*read)(struct seq_file *seq, void *data);
struct device *dev;
};
static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
{
struct debugfs_devm_entry *entry = inode->i_private;
return single_open(f, entry->read, entry->dev);
}
static const struct file_operations debugfs_devm_entry_ops = {
.owner = THIS_MODULE,
.open = debugfs_devm_entry_open,
.release = single_release,
.read = seq_read,
.llseek = seq_lseek
};
/**
* 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))
{
struct debugfs_devm_entry *entry;
if (IS_ERR(parent))
return;
entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
if (!entry)
return;
entry->read = read_fn;
entry->dev = dev;
debugfs_create_file(name, S_IRUGO, parent, entry,
&debugfs_devm_entry_ops);
}
EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);