fs/proc/proc_misc.c

/*
 *  linux/fs/proc/proc_misc.c
 *
 *  linux/fs/proc/array.c
 *  Copyright (C) 1992  by Linus Torvalds
 *  based on ideas by Darren Senn
 *
 *  This used to be the part of array.c. See the rest of history and credits
 *  there. I took this into a separate file and switched the thing to generic
 *  proc_file_inode_operations, leaving in array.c only per-process stuff.
 *  Inumbers allocation made dynamic (via create_proc_entry()).  AV, May 1999.
 *
 * Changes:
 * Fulton Green      :  Encapsulated position metric calculations.
 *			<kernel@FultonGreen.com>
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/fs.h>
#include <linux/tty.h>
#include <linux/string.h>
#include <linux/mman.h>
#include <linux/proc_fs.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/signal.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/seq_file.h>
#include <linux/times.h>
#include <linux/profile.h>
#include <linux/utsname.h>
#include <linux/blkdev.h>
#include <linux/hugetlb.h>
#include <linux/jiffies.h>
#include <linux/sysrq.h>
#include <linux/vmalloc.h>
#include <linux/crash_dump.h>
#include <linux/pid_namespace.h>
#include <linux/compile.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/tlb.h>
#include <asm/div64.h>
#include "internal.h"

#define LOAD_INT(x) ((x) >> FSHIFT)
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
/*
 * Warning: stuff below (imported functions) assumes that its output will fit
 * into one page. For some of those functions it may be wrong. Moreover, we
 * have a way to deal with that gracefully. Right now I used straightforward
 * wrappers, but this needs further analysis wrt potential overflows.
 */
extern int get_hardware_list(char *);
extern int get_stram_list(char *);
extern int get_filesystem_list(char *);
extern int get_exec_domain_list(char *);
extern int get_dma_list(char *);
extern int get_locks_status (char *, char **, off_t, int);

static int proc_calc_metrics(char *page, char **start, off_t off,
				 int count, int *eof, int len)
{
	if (len <= off+count) *eof = 1;
	*start = page + off;
	len -= off;
	if (len>count) len = count;
	if (len<0) len = 0;
	return len;
}

static int loadavg_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int a, b, c;
	int len;

	a = avenrun[0] + (FIXED_1/200);
	b = avenrun[1] + (FIXED_1/200);
	c = avenrun[2] + (FIXED_1/200);
	len = sprintf(page,"%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
		LOAD_INT(a), LOAD_FRAC(a),
		LOAD_INT(b), LOAD_FRAC(b),
		LOAD_INT(c), LOAD_FRAC(c),
		nr_running(), nr_threads, current->nsproxy->pid_ns->last_pid);
	return proc_calc_metrics(page, start, off, count, eof, len);
}

static int uptime_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	struct timespec uptime;
	struct timespec idle;
	int len;
	cputime_t idletime = cputime_add(init_task.utime, init_task.stime);

	do_posix_clock_monotonic_gettime(&uptime);
	cputime_to_timespec(idletime, &idle);
	len = sprintf(page,"%lu.%02lu %lu.%02lu\n",
			(unsigned long) uptime.tv_sec,
			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
			(unsigned long) idle.tv_sec,
			(idle.tv_nsec / (NSEC_PER_SEC / 100)));

	return proc_calc_metrics(page, start, off, count, eof, len);
}

static int meminfo_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	struct sysinfo i;
	int len;
	unsigned long inactive;
	unsigned long active;
	unsigned long free;
	unsigned long committed;
	unsigned long allowed;
	struct vmalloc_info vmi;
	long cached;

	get_zone_counts(&active, &inactive, &free);

/*
 * display in kilobytes.
 */
#define K(x) ((x) << (PAGE_SHIFT - 10))
	si_meminfo(&i);
	si_swapinfo(&i);
	committed = atomic_read(&vm_committed_space);
	allowed = ((totalram_pages - hugetlb_total_pages())
		* sysctl_overcommit_ratio / 100) + total_swap_pages;

	cached = global_page_state(NR_FILE_PAGES) -
			total_swapcache_pages - i.bufferram;
	if (cached < 0)
		cached = 0;

	get_vmalloc_info(&vmi);

	/*
	 * Tagged format, for easy grepping and expansion.
	 */
	len = sprintf(page,
		"MemTotal:     %8lu kB\n"
		"MemFree:      %8lu kB\n"
		"Buffers:      %8lu kB\n"
		"Cached:       %8lu kB\n"
		"SwapCached:   %8lu kB\n"
		"Active:       %8lu kB\n"
		"Inactive:     %8lu kB\n"
#ifdef CONFIG_HIGHMEM
		"HighTotal:    %8lu kB\n"
		"HighFree:     %8lu kB\n"
		"LowTotal:     %8lu kB\n"
		"LowFree:      %8lu kB\n"
#endif
		"SwapTotal:    %8lu kB\n"
		"SwapFree:     %8lu kB\n"
		"Dirty:        %8lu kB\n"
		"Writeback:    %8lu kB\n"
		"AnonPages:    %8lu kB\n"
		"Mapped:       %8lu kB\n"
		"Slab:         %8lu kB\n"
		"SReclaimable: %8lu kB\n"
		"SUnreclaim:   %8lu kB\n"
		"PageTables:   %8lu kB\n"
		"NFS_Unstable: %8lu kB\n"
		"Bounce:       %8lu kB\n"
		"CommitLimit:  %8lu kB\n"
		"Committed_AS: %8lu kB\n"
		"VmallocTotal: %8lu kB\n"
		"VmallocUsed:  %8lu kB\n"
		"VmallocChunk: %8lu kB\n",
		K(i.totalram),
		K(i.freeram),
		K(i.bufferram),
		K(cached),
		K(total_swapcache_pages),
		K(active),
		K(inactive),
#ifdef CONFIG_HIGHMEM
		K(i.totalhigh),
		K(i.freehigh),
		K(i.totalram-i.totalhigh),
		K(i.freeram-i.freehigh),
#endif
		K(i.totalswap),
		K(i.freeswap),
		K(global_page_state(NR_FILE_DIRTY)),
		K(global_page_state(NR_WRITEBACK)),
		K(global_page_state(NR_ANON_PAGES)),
		K(global_page_state(NR_FILE_MAPPED)),
		K(global_page_state(NR_SLAB_RECLAIMABLE) +
				global_page_state(NR_SLAB_UNRECLAIMABLE)),
		K(global_page_state(NR_SLAB_RECLAIMABLE)),
		K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
		K(global_page_state(NR_PAGETABLE)),
		K(global_page_state(NR_UNSTABLE_NFS)),
		K(global_page_state(NR_BOUNCE)),
		K(allowed),
		K(committed),
		(unsigned long)VMALLOC_TOTAL >> 10,
		vmi.used >> 10,
		vmi.largest_chunk >> 10
		);

		len += hugetlb_report_meminfo(page + len);

	return proc_calc_metrics(page, start, off, count, eof, len);
#undef K
}

extern struct seq_operations fragmentation_op;
static int fragmentation_open(struct inode *inode, struct file *file)
{
	(void)inode;
	return seq_open(file, &fragmentation_op);
}

static struct file_operations fragmentation_file_operations = {
	.open		= fragmentation_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

extern struct seq_operations zoneinfo_op;
static int zoneinfo_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &zoneinfo_op);
}

static struct file_operations proc_zoneinfo_file_operations = {
	.open		= zoneinfo_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int version_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len;

	/* FIXED STRING! Don't touch! */
	len = snprintf(page, PAGE_SIZE,
		"%s version %s"
		" (" LINUX_COMPILE_BY "@" LINUX_COMPILE_HOST ")"
		" (" LINUX_COMPILER ")"
		" %s\n",
		utsname()->sysname,
		utsname()->release,
		utsname()->version);
	return proc_calc_metrics(page, start, off, count, eof, len);
}

extern struct seq_operations cpuinfo_op;
static int cpuinfo_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &cpuinfo_op);
}

static struct file_operations proc_cpuinfo_operations = {
	.open		= cpuinfo_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int devinfo_show(struct seq_file *f, void *v)
{
	int i = *(loff_t *) v;

	if (i < CHRDEV_MAJOR_HASH_SIZE) {
		if (i == 0)
			seq_printf(f, "Character devices:\n");
		chrdev_show(f, i);
	}
#ifdef CONFIG_BLOCK
	else {
		i -= CHRDEV_MAJOR_HASH_SIZE;
		if (i == 0)
			seq_printf(f, "\nBlock devices:\n");
		blkdev_show(f, i);
	}
#endif
	return 0;
}

static void *devinfo_start(struct seq_file *f, loff_t *pos)
{
	if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
		return pos;
	return NULL;
}

static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
{
	(*pos)++;
	if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_HASH_SIZE))
		return NULL;
	return pos;
}

static void devinfo_stop(struct seq_file *f, void *v)
{
	/* Nothing to do */
}

static struct seq_operations devinfo_ops = {
	.start = devinfo_start,
	.next  = devinfo_next,
	.stop  = devinfo_stop,
	.show  = devinfo_show
};

static int devinfo_open(struct inode *inode, struct file *filp)
{
	return seq_open(filp, &devinfo_ops);
}

static struct file_operations proc_devinfo_operations = {
	.open		= devinfo_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

extern struct seq_operations vmstat_op;
static int vmstat_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &vmstat_op);
}
static struct file_operations proc_vmstat_file_operations = {
	.open		= vmstat_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

#ifdef CONFIG_PROC_HARDWARE
static int hardware_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len = get_hardware_list(page);
	return proc_calc_metrics(page, start, off, count, eof, len);
}
#endif

#ifdef CONFIG_STRAM_PROC
static int stram_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len = get_stram_list(page);
	return proc_calc_metrics(page, start, off, count, eof, len);
}
#endif

#ifdef CONFIG_BLOCK
extern struct seq_operations partitions_op;
static int partitions_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &partitions_op);
}
static struct file_operations proc_partitions_operations = {
	.open		= partitions_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

extern struct seq_operations diskstats_op;
static int diskstats_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &diskstats_op);
}
static struct file_operations proc_diskstats_operations = {
	.open		= diskstats_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};
#endif

#ifdef CONFIG_MODULES
extern struct seq_operations modules_op;
static int modules_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &modules_op);
}
static struct file_operations proc_modules_operations = {
	.open		= modules_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};
#endif

#ifdef CONFIG_SLAB
extern struct seq_operations slabinfo_op;
extern ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
static int slabinfo_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &slabinfo_op);
}
static struct file_operations proc_slabinfo_operations = {
	.open		= slabinfo_open,
	.read		= seq_read,
	.write		= slabinfo_write,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

#ifdef CONFIG_DEBUG_SLAB_LEAK
extern struct seq_operations slabstats_op;
static int slabstats_open(struct inode *inode, struct file *file)
{
	unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
	int ret = -ENOMEM;
	if (n) {
		ret = seq_open(file, &slabstats_op);
		if (!ret) {
			struct seq_file *m = file->private_data;
			*n = PAGE_SIZE / (2 * sizeof(unsigned long));
			m->private = n;
			n = NULL;
		}
		kfree(n);
	}
	return ret;
}

static int slabstats_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = file->private_data;
	kfree(m->private);
	return seq_release(inode, file);
}

static struct file_operations proc_slabstats_operations = {
	.open		= slabstats_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= slabstats_release,
};
#endif
#endif

static int show_stat(struct seq_file *p, void *v)
{
	int i;
	unsigned long jif;
	cputime64_t user, nice, system, idle, iowait, irq, softirq, steal;
	u64 sum = 0;

	user = nice = system = idle = iowait =
		irq = softirq = steal = cputime64_zero;
	jif = - wall_to_monotonic.tv_sec;
	if (wall_to_monotonic.tv_nsec)
		--jif;

	for_each_possible_cpu(i) {
		int j;

		user = cputime64_add(user, kstat_cpu(i).cpustat.user);
		nice = cputime64_add(nice, kstat_cpu(i).cpustat.nice);
		system = cputime64_add(system, kstat_cpu(i).cpustat.system);
		idle = cputime64_add(idle, kstat_cpu(i).cpustat.idle);
		iowait = cputime64_add(iowait, kstat_cpu(i).cpustat.iowait);
		irq = cputime64_add(irq, kstat_cpu(i).cpustat.irq);
		softirq = cputime64_add(softirq, kstat_cpu(i).cpustat.softirq);
		steal = cputime64_add(steal, kstat_cpu(i).cpustat.steal);
		for (j = 0 ; j < NR_IRQS ; j++)
			sum += kstat_cpu(i).irqs[j];
	}

	seq_printf(p, "cpu  %llu %llu %llu %llu %llu %llu %llu %llu\n",
		(unsigned long long)cputime64_to_clock_t(user),
		(unsigned long long)cputime64_to_clock_t(nice),
		(unsigned long long)cputime64_to_clock_t(system),
		(unsigned long long)cputime64_to_clock_t(idle),
		(unsigned long long)cputime64_to_clock_t(iowait),
		(unsigned long long)cputime64_to_clock_t(irq),
		(unsigned long long)cputime64_to_clock_t(softirq),
		(unsigned long long)cputime64_to_clock_t(steal));
	for_each_online_cpu(i) {

		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
		user = kstat_cpu(i).cpustat.user;
		nice = kstat_cpu(i).cpustat.nice;
		system = kstat_cpu(i).cpustat.system;
		idle = kstat_cpu(i).cpustat.idle;
		iowait = kstat_cpu(i).cpustat.iowait;
		irq = kstat_cpu(i).cpustat.irq;
		softirq = kstat_cpu(i).cpustat.softirq;
		steal = kstat_cpu(i).cpustat.steal;
		seq_printf(p, "cpu%d %llu %llu %llu %llu %llu %llu %llu %llu\n",
			i,
			(unsigned long long)cputime64_to_clock_t(user),
			(unsigned long long)cputime64_to_clock_t(nice),
			(unsigned long long)cputime64_to_clock_t(system),
			(unsigned long long)cputime64_to_clock_t(idle),
			(unsigned long long)cputime64_to_clock_t(iowait),
			(unsigned long long)cputime64_to_clock_t(irq),
			(unsigned long long)cputime64_to_clock_t(softirq),
			(unsigned long long)cputime64_to_clock_t(steal));
	}
	seq_printf(p, "intr %llu", (unsigned long long)sum);

#if !defined(CONFIG_PPC64) && !defined(CONFIG_ALPHA) && !defined(CONFIG_IA64)
	for (i = 0; i < NR_IRQS; i++)
		seq_printf(p, " %u", kstat_irqs(i));
#endif

	seq_printf(p,
		"\nctxt %llu\n"
		"btime %lu\n"
		"processes %lu\n"
		"procs_running %lu\n"
		"procs_blocked %lu\n",
		nr_context_switches(),
		(unsigned long)jif,
		total_forks,
		nr_running(),
		nr_iowait());

	return 0;
}

static int stat_open(struct inode *inode, struct file *file)
{
	unsigned size = 4096 * (1 + num_possible_cpus() / 32);
	char *buf;
	struct seq_file *m;
	int res;

	/* don't ask for more than the kmalloc() max size, currently 128 KB */
	if (size > 128 * 1024)
		size = 128 * 1024;
	buf = kmalloc(size, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	res = single_open(file, show_stat, NULL);
	if (!res) {
		m = file->private_data;
		m->buf = buf;
		m->size = size;
	} else
		kfree(buf);
	return res;
}
static struct file_operations proc_stat_operations = {
	.open		= stat_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

/*
 * /proc/interrupts
 */
static void *int_seq_start(struct seq_file *f, loff_t *pos)
{
	return (*pos <= NR_IRQS) ? pos : NULL;
}

static void *int_seq_next(struct seq_file *f, void *v, loff_t *pos)
{
	(*pos)++;
	if (*pos > NR_IRQS)
		return NULL;
	return pos;
}

static void int_seq_stop(struct seq_file *f, void *v)
{
	/* Nothing to do */
}


extern int show_interrupts(struct seq_file *f, void *v); /* In arch code */
static struct seq_operations int_seq_ops = {
	.start = int_seq_start,
	.next  = int_seq_next,
	.stop  = int_seq_stop,
	.show  = show_interrupts
};

static int interrupts_open(struct inode *inode, struct file *filp)
{
	return seq_open(filp, &int_seq_ops);
}

static struct file_operations proc_interrupts_operations = {
	.open		= interrupts_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int filesystems_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len = get_filesystem_list(page);
	return proc_calc_metrics(page, start, off, count, eof, len);
}

static int cmdline_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len;

	len = sprintf(page, "%s\n", saved_command_line);
	return proc_calc_metrics(page, start, off, count, eof, len);
}

static int locks_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len = get_locks_status(page, start, off, count);

	if (len < count)
		*eof = 1;
	return len;
}

static int execdomains_read_proc(char *page, char **start, off_t off,
				 int count, int *eof, void *data)
{
	int len = get_exec_domain_list(page);
	return proc_calc_metrics(page, start, off, count, eof, len);
}

#ifdef CONFIG_MAGIC_SYSRQ
/*
 * writing 'C' to /proc/sysrq-trigger is like sysrq-C
 */
static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
				   size_t count, loff_t *ppos)
{
	if (count) {
		char c;

		if (get_user(c, buf))
			return -EFAULT;
		__handle_sysrq(c, NULL, 0);
	}
	return count;
}

static struct file_operations proc_sysrq_trigger_operations = {
	.write		= write_sysrq_trigger,
};
#endif

struct proc_dir_entry *proc_root_kcore;

void create_seq_entry(char *name, mode_t mode, const struct file_operations *f)
{
	struct proc_dir_entry *entry;
	entry = create_proc_entry(name, mode, NULL);
	if (entry)
		entry->proc_fops = f;
}

void __init proc_misc_init(void)
{
	struct proc_dir_entry *entry;
	static struct {
		char *name;
		int (*read_proc)(char*,char**,off_t,int,int*,void*);
	} *p, simple_ones[] = {
		{"loadavg",     loadavg_read_proc},
		{"uptime",	uptime_read_proc},
		{"meminfo",	meminfo_read_proc},
		{"version",	version_read_proc},
#ifdef CONFIG_PROC_HARDWARE
		{"hardware",	hardware_read_proc},
#endif
#ifdef CONFIG_STRAM_PROC
		{"stram",	stram_read_proc},
#endif
		{"filesystems",	filesystems_read_proc},
		{"cmdline",	cmdline_read_proc},
		{"locks",	locks_read_proc},
		{"execdomains",	execdomains_read_proc},
		{NULL,}
	};
	for (p = simple_ones; p->name; p++)
		create_proc_read_entry(p->name, 0, NULL, p->read_proc, NULL);

	proc_symlink("mounts", NULL, "self/mounts");

	/* And now for trickier ones */
#ifdef CONFIG_PRINTK
	entry = create_proc_entry("kmsg", S_IRUSR, &proc_root);
	if (entry)
		entry->proc_fops = &proc_kmsg_operations;
#endif
	create_seq_entry("devices", 0, &proc_devinfo_operations);
	create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations);
#ifdef CONFIG_BLOCK
	create_seq_entry("partitions", 0, &proc_partitions_operations);
#endif
	create_seq_entry("stat", 0, &proc_stat_operations);
	create_seq_entry("interrupts", 0, &proc_interrupts_operations);
#ifdef CONFIG_SLAB
	create_seq_entry("slabinfo",S_IWUSR|S_IRUGO,&proc_slabinfo_operations);
#ifdef CONFIG_DEBUG_SLAB_LEAK
	create_seq_entry("slab_allocators", 0 ,&proc_slabstats_operations);
#endif
#endif
	create_seq_entry("buddyinfo",S_IRUGO, &fragmentation_file_operations);
	create_seq_entry("vmstat",S_IRUGO, &proc_vmstat_file_operations);
	create_seq_entry("zoneinfo",S_IRUGO, &proc_zoneinfo_file_operations);
#ifdef CONFIG_BLOCK
	create_seq_entry("diskstats", 0, &proc_diskstats_operations);
#endif
#ifdef CONFIG_MODULES
	create_seq_entry("modules", 0, &proc_modules_operations);
#endif
#ifdef CONFIG_SCHEDSTATS
	create_seq_entry("schedstat", 0, &proc_schedstat_operations);
#endif
#ifdef CONFIG_PROC_KCORE
	proc_root_kcore = create_proc_entry("kcore", S_IRUSR, NULL);
	if (proc_root_kcore) {
		proc_root_kcore->proc_fops = &proc_kcore_operations;
		proc_root_kcore->size =
				(size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;
	}
#endif
#ifdef CONFIG_PROC_VMCORE
	proc_vmcore = create_proc_entry("vmcore", S_IRUSR, NULL);
	if (proc_vmcore)
		proc_vmcore->proc_fops = &proc_vmcore_operations;
#endif
#ifdef CONFIG_MAGIC_SYSRQ
	entry = create_proc_entry("sysrq-trigger", S_IWUSR, NULL);
	if (entry)
		entry->proc_fops = &proc_sysrq_trigger_operations;
#endif
}