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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/**
2 * @file oprofilefs.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author John Levon
8 *
9 * A simple filesystem for configuration and
10 * access of oprofile.
11 */
12
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/oprofile.h>
16#include <linux/fs.h>
17#include <linux/pagemap.h>
18#include <asm/uaccess.h>
19
20#include "oprof.h"
21
22#define OPROFILEFS_MAGIC 0x6f70726f
23
Thomas Gleixner2d21a292009-07-25 16:18:34 +020024DEFINE_RAW_SPINLOCK(oprofilefs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
Robert Richter25ad2912008-09-05 17:12:36 +020026static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -070027{
Robert Richter25ad2912008-09-05 17:12:36 +020028 struct inode *inode = new_inode(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -040031 inode->i_ino = get_next_ino();
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
34 }
35 return inode;
36}
37
38
Alexey Dobriyanb87221d2009-09-21 17:01:09 -070039static const struct super_operations s_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 .statfs = simple_statfs,
41 .drop_inode = generic_delete_inode,
42};
43
44
Robert Richter25ad2912008-09-05 17:12:36 +020045ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070046{
47 return simple_read_from_buffer(buf, count, offset, str, strlen(str));
48}
49
50
51#define TMPBUFSIZE 50
52
Robert Richter25ad2912008-09-05 17:12:36 +020053ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070054{
55 char tmpbuf[TMPBUFSIZE];
56 size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
57 if (maxlen > TMPBUFSIZE)
58 maxlen = TMPBUFSIZE;
59 return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
60}
61
62
Robert Richter913050b2011-12-19 16:38:30 +010063/*
64 * Note: If oprofilefs_ulong_from_user() returns 0, then *val remains
65 * unchanged and might be uninitialized. This follows write syscall
66 * implementation when count is zero: "If count is zero ... [and if]
67 * no errors are detected, 0 will be returned without causing any
68 * other effect." (man 2 write)
69 */
Robert Richter25ad2912008-09-05 17:12:36 +020070int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -070071{
72 char tmpbuf[TMPBUFSIZE];
Jiri Kosina4dfc8962007-03-28 18:12:34 +020073 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75 if (!count)
76 return 0;
77
78 if (count > TMPBUFSIZE - 1)
79 return -EINVAL;
80
81 memset(tmpbuf, 0x0, TMPBUFSIZE);
82
83 if (copy_from_user(tmpbuf, buf, count))
84 return -EFAULT;
85
Thomas Gleixner2d21a292009-07-25 16:18:34 +020086 raw_spin_lock_irqsave(&oprofilefs_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 *val = simple_strtoul(tmpbuf, NULL, 0);
Thomas Gleixner2d21a292009-07-25 16:18:34 +020088 raw_spin_unlock_irqrestore(&oprofilefs_lock, flags);
Robert Richter913050b2011-12-19 16:38:30 +010089 return count;
Linus Torvalds1da177e2005-04-16 15:20:36 -070090}
91
92
Robert Richter25ad2912008-09-05 17:12:36 +020093static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070094{
Robert Richter25ad2912008-09-05 17:12:36 +020095 unsigned long *val = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 return oprofilefs_ulong_to_user(*val, buf, count, offset);
97}
98
99
Robert Richter25ad2912008-09-05 17:12:36 +0200100static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101{
Robert Richter7df01d92010-10-04 21:09:36 +0200102 unsigned long value;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 int retval;
104
105 if (*offset)
106 return -EINVAL;
107
Robert Richter7df01d92010-10-04 21:09:36 +0200108 retval = oprofilefs_ulong_from_user(&value, buf, count);
Robert Richter913050b2011-12-19 16:38:30 +0100109 if (retval <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return retval;
Robert Richter7df01d92010-10-04 21:09:36 +0200111
112 retval = oprofile_set_ulong(file->private_data, value);
113 if (retval)
114 return retval;
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 return count;
117}
118
119
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800120static const struct file_operations ulong_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 .read = ulong_read_file,
122 .write = ulong_write_file,
Stephen Boyd234e3402012-04-05 14:25:11 -0700123 .open = simple_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200124 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125};
126
127
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800128static const struct file_operations ulong_ro_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 .read = ulong_read_file,
Stephen Boyd234e3402012-04-05 14:25:11 -0700130 .open = simple_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200131 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132};
133
134
Al Viro6af4ea02013-07-19 16:10:36 +0400135static int __oprofilefs_create_file(struct dentry *root, char const *name,
136 const struct file_operations *fops, int perm, void *priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137{
Robert Richter25ad2912008-09-05 17:12:36 +0200138 struct dentry *dentry;
139 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
Al Viro59551022016-01-22 15:40:57 -0500141 inode_lock(d_inode(root));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 dentry = d_alloc_name(root, name);
Al Viro3f3834c2013-01-28 14:42:42 -0500143 if (!dentry) {
Al Viro59551022016-01-22 15:40:57 -0500144 inode_unlock(d_inode(root));
Robert Richter4fdaa7b2010-08-19 10:50:26 +0200145 return -ENOMEM;
Al Viro3f3834c2013-01-28 14:42:42 -0500146 }
Al Viro6af4ea02013-07-19 16:10:36 +0400147 inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 if (!inode) {
149 dput(dentry);
Al Viro59551022016-01-22 15:40:57 -0500150 inode_unlock(d_inode(root));
Robert Richter4fdaa7b2010-08-19 10:50:26 +0200151 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 }
153 inode->i_fop = fops;
Al Viro3f3834c2013-01-28 14:42:42 -0500154 inode->i_private = priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 d_add(dentry, inode);
Al Viro59551022016-01-22 15:40:57 -0500156 inode_unlock(d_inode(root));
Robert Richter4fdaa7b2010-08-19 10:50:26 +0200157 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158}
159
160
Al Viro6af4ea02013-07-19 16:10:36 +0400161int oprofilefs_create_ulong(struct dentry *root,
Robert Richter25ad2912008-09-05 17:12:36 +0200162 char const *name, unsigned long *val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163{
Al Viro6af4ea02013-07-19 16:10:36 +0400164 return __oprofilefs_create_file(root, name,
Robert Richter4fdaa7b2010-08-19 10:50:26 +0200165 &ulong_fops, 0644, val);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166}
167
168
Al Viro6af4ea02013-07-19 16:10:36 +0400169int oprofilefs_create_ro_ulong(struct dentry *root,
Robert Richter25ad2912008-09-05 17:12:36 +0200170 char const *name, unsigned long *val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171{
Al Viro6af4ea02013-07-19 16:10:36 +0400172 return __oprofilefs_create_file(root, name,
Robert Richter4fdaa7b2010-08-19 10:50:26 +0200173 &ulong_ro_fops, 0444, val);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174}
175
176
Robert Richter25ad2912008-09-05 17:12:36 +0200177static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178{
Robert Richter25ad2912008-09-05 17:12:36 +0200179 atomic_t *val = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
181}
Robert Richter6a180372008-10-16 15:01:40 +0200182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800184static const struct file_operations atomic_ro_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 .read = atomic_read_file,
Stephen Boyd234e3402012-04-05 14:25:11 -0700186 .open = simple_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200187 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188};
Robert Richter6a180372008-10-16 15:01:40 +0200189
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
Al Viro6af4ea02013-07-19 16:10:36 +0400191int oprofilefs_create_ro_atomic(struct dentry *root,
Robert Richter25ad2912008-09-05 17:12:36 +0200192 char const *name, atomic_t *val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193{
Al Viro6af4ea02013-07-19 16:10:36 +0400194 return __oprofilefs_create_file(root, name,
Robert Richter4fdaa7b2010-08-19 10:50:26 +0200195 &atomic_ro_fops, 0444, val);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196}
197
Robert Richter6a180372008-10-16 15:01:40 +0200198
Al Viro6af4ea02013-07-19 16:10:36 +0400199int oprofilefs_create_file(struct dentry *root,
Robert Richter25ad2912008-09-05 17:12:36 +0200200 char const *name, const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201{
Al Viro6af4ea02013-07-19 16:10:36 +0400202 return __oprofilefs_create_file(root, name, fops, 0644, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203}
204
205
Al Viro6af4ea02013-07-19 16:10:36 +0400206int oprofilefs_create_file_perm(struct dentry *root,
Robert Richter25ad2912008-09-05 17:12:36 +0200207 char const *name, const struct file_operations *fops, int perm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
Al Viro6af4ea02013-07-19 16:10:36 +0400209 return __oprofilefs_create_file(root, name, fops, perm, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210}
211
212
Al Viroecde2822013-07-19 15:58:27 +0400213struct dentry *oprofilefs_mkdir(struct dentry *parent, char const *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
Robert Richter25ad2912008-09-05 17:12:36 +0200215 struct dentry *dentry;
216 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217
Al Viro59551022016-01-22 15:40:57 -0500218 inode_lock(d_inode(parent));
Al Viroecde2822013-07-19 15:58:27 +0400219 dentry = d_alloc_name(parent, name);
Al Viro3f3834c2013-01-28 14:42:42 -0500220 if (!dentry) {
Al Viro59551022016-01-22 15:40:57 -0500221 inode_unlock(d_inode(parent));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 return NULL;
Al Viro3f3834c2013-01-28 14:42:42 -0500223 }
Al Viroecde2822013-07-19 15:58:27 +0400224 inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 if (!inode) {
226 dput(dentry);
Al Viro59551022016-01-22 15:40:57 -0500227 inode_unlock(d_inode(parent));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 return NULL;
229 }
230 inode->i_op = &simple_dir_inode_operations;
231 inode->i_fop = &simple_dir_operations;
232 d_add(dentry, inode);
Al Viro59551022016-01-22 15:40:57 -0500233 inode_unlock(d_inode(parent));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 return dentry;
235}
236
237
Robert Richter25ad2912008-09-05 17:12:36 +0200238static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
Robert Richter25ad2912008-09-05 17:12:36 +0200240 struct inode *root_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300242 sb->s_blocksize = PAGE_SIZE;
243 sb->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 sb->s_magic = OPROFILEFS_MAGIC;
245 sb->s_op = &s_ops;
246 sb->s_time_gran = 1;
247
248 root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
249 if (!root_inode)
250 return -ENOMEM;
251 root_inode->i_op = &simple_dir_inode_operations;
252 root_inode->i_fop = &simple_dir_operations;
Al Viro318ceed2012-02-12 22:08:01 -0500253 sb->s_root = d_make_root(root_inode);
254 if (!sb->s_root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
Al Viroa9e599e2013-07-19 15:47:29 +0400257 oprofile_create_files(sb->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 // FIXME: verify kill_litter_super removes our dentries
260 return 0;
261}
262
263
Al Virofc14f2f2010-07-25 01:48:30 +0400264static struct dentry *oprofilefs_mount(struct file_system_type *fs_type,
265 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266{
Al Virofc14f2f2010-07-25 01:48:30 +0400267 return mount_single(fs_type, flags, data, oprofilefs_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268}
269
270
271static struct file_system_type oprofilefs_type = {
272 .owner = THIS_MODULE,
273 .name = "oprofilefs",
Al Virofc14f2f2010-07-25 01:48:30 +0400274 .mount = oprofilefs_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 .kill_sb = kill_litter_super,
276};
Eric W. Biederman7f78e032013-03-02 19:39:14 -0800277MODULE_ALIAS_FS("oprofilefs");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
279
280int __init oprofilefs_register(void)
281{
282 return register_filesystem(&oprofilefs_type);
283}
284
285
286void __exit oprofilefs_unregister(void)
287{
288 unregister_filesystem(&oprofilefs_type);
289}