diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/oprofile/oprofilefs.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c new file mode 100644 index 000000000..4ea089793 --- /dev/null +++ b/drivers/oprofile/oprofilefs.c @@ -0,0 +1,292 @@ +/** + * @file oprofilefs.c + * + * @remark Copyright 2002 OProfile authors + * @remark Read the file COPYING + * + * @author John Levon + * + * A simple filesystem for configuration and + * access of oprofile. + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/oprofile.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/uaccess.h> + +#include "oprof.h" + +#define OPROFILEFS_MAGIC 0x6f70726f + +DEFINE_RAW_SPINLOCK(oprofilefs_lock); + +static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode) +{ + struct inode *inode = new_inode(sb); + + if (inode) { + inode->i_ino = get_next_ino(); + inode->i_mode = mode; + inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); + } + return inode; +} + + +static const struct super_operations s_ops = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, +}; + + +ssize_t oprofilefs_str_to_user(char const *str, char __user *buf, size_t count, loff_t *offset) +{ + return simple_read_from_buffer(buf, count, offset, str, strlen(str)); +} + + +#define TMPBUFSIZE 50 + +ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset) +{ + char tmpbuf[TMPBUFSIZE]; + size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val); + if (maxlen > TMPBUFSIZE) + maxlen = TMPBUFSIZE; + return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen); +} + + +/* + * Note: If oprofilefs_ulong_from_user() returns 0, then *val remains + * unchanged and might be uninitialized. This follows write syscall + * implementation when count is zero: "If count is zero ... [and if] + * no errors are detected, 0 will be returned without causing any + * other effect." (man 2 write) + */ +int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count) +{ + char tmpbuf[TMPBUFSIZE]; + unsigned long flags; + + if (!count) + return 0; + + if (count > TMPBUFSIZE - 1) + return -EINVAL; + + memset(tmpbuf, 0x0, TMPBUFSIZE); + + if (copy_from_user(tmpbuf, buf, count)) + return -EFAULT; + + raw_spin_lock_irqsave(&oprofilefs_lock, flags); + *val = simple_strtoul(tmpbuf, NULL, 0); + raw_spin_unlock_irqrestore(&oprofilefs_lock, flags); + return count; +} + + +static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) +{ + unsigned long *val = file->private_data; + return oprofilefs_ulong_to_user(*val, buf, count, offset); +} + + +static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset) +{ + unsigned long value; + int retval; + + if (*offset) + return -EINVAL; + + retval = oprofilefs_ulong_from_user(&value, buf, count); + if (retval <= 0) + return retval; + + retval = oprofile_set_ulong(file->private_data, value); + if (retval) + return retval; + + return count; +} + + +static const struct file_operations ulong_fops = { + .read = ulong_read_file, + .write = ulong_write_file, + .open = simple_open, + .llseek = default_llseek, +}; + + +static const struct file_operations ulong_ro_fops = { + .read = ulong_read_file, + .open = simple_open, + .llseek = default_llseek, +}; + + +static int __oprofilefs_create_file(struct dentry *root, char const *name, + const struct file_operations *fops, int perm, void *priv) +{ + struct dentry *dentry; + struct inode *inode; + + if (!root) + return -ENOMEM; + + inode_lock(d_inode(root)); + dentry = d_alloc_name(root, name); + if (!dentry) { + inode_unlock(d_inode(root)); + return -ENOMEM; + } + inode = oprofilefs_get_inode(root->d_sb, S_IFREG | perm); + if (!inode) { + dput(dentry); + inode_unlock(d_inode(root)); + return -ENOMEM; + } + inode->i_fop = fops; + inode->i_private = priv; + d_add(dentry, inode); + inode_unlock(d_inode(root)); + return 0; +} + + +int oprofilefs_create_ulong(struct dentry *root, + char const *name, unsigned long *val) +{ + return __oprofilefs_create_file(root, name, + &ulong_fops, 0644, val); +} + + +int oprofilefs_create_ro_ulong(struct dentry *root, + char const *name, unsigned long *val) +{ + return __oprofilefs_create_file(root, name, + &ulong_ro_fops, 0444, val); +} + + +static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset) +{ + atomic_t *val = file->private_data; + return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset); +} + + +static const struct file_operations atomic_ro_fops = { + .read = atomic_read_file, + .open = simple_open, + .llseek = default_llseek, +}; + + +int oprofilefs_create_ro_atomic(struct dentry *root, + char const *name, atomic_t *val) +{ + return __oprofilefs_create_file(root, name, + &atomic_ro_fops, 0444, val); +} + + +int oprofilefs_create_file(struct dentry *root, + char const *name, const struct file_operations *fops) +{ + return __oprofilefs_create_file(root, name, fops, 0644, NULL); +} + + +int oprofilefs_create_file_perm(struct dentry *root, + char const *name, const struct file_operations *fops, int perm) +{ + return __oprofilefs_create_file(root, name, fops, perm, NULL); +} + + +struct dentry *oprofilefs_mkdir(struct dentry *parent, char const *name) +{ + struct dentry *dentry; + struct inode *inode; + + inode_lock(d_inode(parent)); + dentry = d_alloc_name(parent, name); + if (!dentry) { + inode_unlock(d_inode(parent)); + return NULL; + } + inode = oprofilefs_get_inode(parent->d_sb, S_IFDIR | 0755); + if (!inode) { + dput(dentry); + inode_unlock(d_inode(parent)); + return NULL; + } + inode->i_op = &simple_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + d_add(dentry, inode); + inode_unlock(d_inode(parent)); + return dentry; +} + + +static int oprofilefs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *root_inode; + + sb->s_blocksize = PAGE_SIZE; + sb->s_blocksize_bits = PAGE_SHIFT; + sb->s_magic = OPROFILEFS_MAGIC; + sb->s_op = &s_ops; + sb->s_time_gran = 1; + + root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755); + if (!root_inode) + return -ENOMEM; + root_inode->i_op = &simple_dir_inode_operations; + root_inode->i_fop = &simple_dir_operations; + sb->s_root = d_make_root(root_inode); + if (!sb->s_root) + return -ENOMEM; + + oprofile_create_files(sb->s_root); + + // FIXME: verify kill_litter_super removes our dentries + return 0; +} + + +static struct dentry *oprofilefs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return mount_single(fs_type, flags, data, oprofilefs_fill_super); +} + + +static struct file_system_type oprofilefs_type = { + .owner = THIS_MODULE, + .name = "oprofilefs", + .mount = oprofilefs_mount, + .kill_sb = kill_litter_super, +}; +MODULE_ALIAS_FS("oprofilefs"); + + +int __init oprofilefs_register(void) +{ + return register_filesystem(&oprofilefs_type); +} + + +void __exit oprofilefs_unregister(void) +{ + unregister_filesystem(&oprofilefs_type); +} |