Labels:black | darkness OCR: Allows a driver to write data in user space, which is in a different segment than the kernel. When entering the kernel through a system call, a selector for the current user space segment is put in the fs segment register, thus the names. 3 Note: these functions may cause implicit I/O, if the memory being accessed has been swapped out, and therefore pre-emption may occur at this point. Do not include these functions in critical sections of your code even if the critical sections are protected by cli ()/sti () pairs, because that implicit I/O will violate the integrity of your cli () /sti() pair. If you need to get at user-space memory, copy it to kernel-space memory before you enter your critical section. These functions take two arguments: val Value to write addr Address to write data to. Defined in: asm/segment.h See also: memcpy *fs(), get_user*(), cli(), sti(). register *dev() int register_chrdev(unsigned int major, const char *name, struct file_operations *fops) int register_blkdev(unsigned int major, const char *name, struct file_operations *fops) #include <linux/fs.h> #include <linux/errno.h>
