2 * linux/kernel/printk.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * Modified to make sys_syslog() more flexible: added commands to
7 * return the last 4k of kernel messages, regardless of whether
8 * they've been read or not. Added option to suppress kernel printk's
9 * to the console. Added hook for sending the console messages
10 * elsewhere, in preparation for a serial line console (someday).
12 * Modified for sysctl support, 1/8/97, Chris Horn.
13 * Fixed SMP synchronization, 08/08/99, Manfred Spraul
14 * manfred@colorfullife.com
15 * Rewrote bits to get rid of console_lock
16 * 01Mar01 Andrew Morton <andrewm@uow.edu.au>
19 #include <linux/kernel.h>
21 #include <linux/tty.h>
22 #include <linux/tty_driver.h>
23 #include <linux/smp_lock.h>
24 #include <linux/console.h>
25 #include <linux/init.h>
26 #include <linux/module.h>
27 #include <linux/interrupt.h> /* For in_interrupt() */
28 #include <linux/config.h>
29 #include <linux/delay.h>
30 #include <linux/smp.h>
31 #include <linux/security.h>
32 #include <linux/bootmem.h>
33 #include <linux/syscalls.h>
34 #include <linux/vs_base.h>
35 #include <linux/vs_cvirt.h>
37 #include <asm/uaccess.h>
39 #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
41 /* printk's without a loglevel use this.. */
42 #define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */
44 /* We show everything that is MORE important than this.. */
45 #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
46 #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
48 DECLARE_WAIT_QUEUE_HEAD(log_wait);
50 int console_printk[4] = {
51 DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
52 DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
53 MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */
54 DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
57 EXPORT_SYMBOL(console_printk);
60 * Low lever drivers may need that to know if they can schedule in
61 * their unblank() callback or not. So let's export it.
64 EXPORT_SYMBOL(oops_in_progress);
67 * console_sem protects the console_drivers list, and also
68 * provides serialisation for access to the entire console
71 static DECLARE_MUTEX(console_sem);
72 struct console *console_drivers;
74 * This is used for debugging the mess that is the VT code by
75 * keeping track if we have the console semaphore held. It's
76 * definitely not the perfect debug tool (we don't know if _WE_
77 * hold it are racing, but it helps tracking those weird code
78 * path in the console code where we end up in places I want
79 * locked without the console sempahore held
81 static int console_locked;
84 * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
85 * It is also used in interesting ways to provide interlocking in
86 * release_console_sem().
88 static DEFINE_SPINLOCK(logbuf_lock);
90 #define LOG_BUF_MASK (log_buf_len-1)
91 #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
94 * The indices into log_buf are not constrained to log_buf_len - they
95 * must be masked before subscripting
97 static unsigned long log_start; /* Index into log_buf: next char to be read by syslog() */
98 static unsigned long con_start; /* Index into log_buf: next char to be sent to consoles */
99 static unsigned long log_end; /* Index into log_buf: most-recently-written-char + 1 */
102 * Array of consoles built from command line options (console=)
104 struct console_cmdline
106 char name[8]; /* Name of the driver */
107 int index; /* Minor dev. to use */
108 char *options; /* Options for the driver */
111 #define MAX_CMDLINECONSOLES 8
113 static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
114 static int selected_console = -1;
115 static int preferred_console = -1;
117 /* Flag: console code may call schedule() */
118 static int console_may_schedule;
122 static char __log_buf[__LOG_BUF_LEN];
123 static char *log_buf = __log_buf;
124 static int log_buf_len = __LOG_BUF_LEN;
125 static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
128 * Setup a list of consoles. Called from init/main.c
130 static int __init console_setup(char *str)
132 char name[sizeof(console_cmdline[0].name)];
137 * Decode str into name, index, options.
139 if (str[0] >= '0' && str[0] <= '9') {
140 strcpy(name, "ttyS");
141 strncpy(name + 4, str, sizeof(name) - 5);
143 strncpy(name, str, sizeof(name) - 1);
144 name[sizeof(name) - 1] = 0;
145 if ((options = strchr(str, ',')) != NULL)
148 if (!strcmp(str, "ttya"))
149 strcpy(name, "ttyS0");
150 if (!strcmp(str, "ttyb"))
151 strcpy(name, "ttyS1");
153 for (s = name; *s; s++)
154 if ((*s >= '0' && *s <= '9') || *s == ',')
156 idx = simple_strtoul(s, NULL, 10);
159 add_preferred_console(name, idx, options);
163 __setup("console=", console_setup);
165 static int __init log_buf_len_setup(char *str)
167 unsigned long size = memparse(str, &str);
171 size = roundup_pow_of_two(size);
172 if (size > log_buf_len) {
173 unsigned long start, dest_idx, offset;
176 new_log_buf = alloc_bootmem(size);
178 printk(KERN_WARNING "log_buf_len: allocation failed\n");
182 spin_lock_irqsave(&logbuf_lock, flags);
184 log_buf = new_log_buf;
186 offset = start = min(con_start, log_start);
188 while (start != log_end) {
189 log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)];
196 spin_unlock_irqrestore(&logbuf_lock, flags);
198 printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
204 __setup("log_buf_len=", log_buf_len_setup);
207 * Commands to do_syslog:
209 * 0 -- Close the log. Currently a NOP.
210 * 1 -- Open the log. Currently a NOP.
211 * 2 -- Read from the log.
212 * 3 -- Read all messages remaining in the ring buffer.
213 * 4 -- Read and clear all messages remaining in the ring buffer
214 * 5 -- Clear ring buffer.
215 * 6 -- Disable printk's to console
216 * 7 -- Enable printk's to console
217 * 8 -- Set level of messages printed to console
218 * 9 -- Return number of unread characters in the log buffer
219 * 10 -- Return size of the log buffer
221 int do_syslog(int type, char __user *buf, int len)
223 unsigned long i, j, limit, count;
228 error = security_syslog(type);
232 if ((type >= 2) && (type <= 4)) {
239 if (!access_ok(VERIFY_WRITE, buf, len)) {
244 if (!vx_check(0, VX_ADMIN|VX_WATCH))
245 return vx_do_syslog(type, buf, len);
248 case 0: /* Close log */
250 case 1: /* Open log */
252 case 2: /* Read from log */
253 error = wait_event_interruptible(log_wait,
254 (log_start - log_end));
258 spin_lock_irq(&logbuf_lock);
259 while (!error && (log_start != log_end) && i < len) {
260 c = LOG_BUF(log_start);
262 spin_unlock_irq(&logbuf_lock);
263 error = __put_user(c,buf);
267 spin_lock_irq(&logbuf_lock);
269 spin_unlock_irq(&logbuf_lock);
273 case 4: /* Read/clear last kernel messages */
276 case 3: /* Read last kernel messages */
278 if (count > log_buf_len)
280 spin_lock_irq(&logbuf_lock);
281 if (count > logged_chars)
282 count = logged_chars;
287 * __put_user() could sleep, and while we sleep
288 * printk() could overwrite the messages
289 * we try to copy to user space. Therefore
290 * the messages are copied in reverse. <manfreds>
292 for (i = 0; i < count && !error; i++) {
294 if (j + log_buf_len < log_end)
297 spin_unlock_irq(&logbuf_lock);
298 error = __put_user(c,&buf[count-1-i]);
300 spin_lock_irq(&logbuf_lock);
302 spin_unlock_irq(&logbuf_lock);
307 int offset = count-error;
308 /* buffer overflow during copy, correct user buffer. */
309 for (i = 0; i < error; i++) {
310 if (__get_user(c,&buf[i+offset]) ||
311 __put_user(c,&buf[i])) {
319 case 5: /* Clear ring buffer */
322 case 6: /* Disable logging to console */
323 console_loglevel = minimum_console_loglevel;
325 case 7: /* Enable logging to console */
326 console_loglevel = default_console_loglevel;
328 case 8: /* Set level of messages printed to console */
330 if (len < 1 || len > 8)
332 if (len < minimum_console_loglevel)
333 len = minimum_console_loglevel;
334 console_loglevel = len;
337 case 9: /* Number of chars in the log buffer */
338 error = log_end - log_start;
340 case 10: /* Size of the log buffer */
351 asmlinkage long sys_syslog(int type, char __user *buf, int len)
353 return do_syslog(type, buf, len);
357 * Call the console drivers on a range of log_buf
359 static void __call_console_drivers(unsigned long start, unsigned long end)
363 for (con = console_drivers; con; con = con->next) {
364 if ((con->flags & CON_ENABLED) && con->write)
365 con->write(con, &LOG_BUF(start), end - start);
370 * Write out chars from start to end - 1 inclusive
372 static void _call_console_drivers(unsigned long start,
373 unsigned long end, int msg_log_level)
375 if (msg_log_level < console_loglevel &&
376 console_drivers && start != end) {
377 if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
379 __call_console_drivers(start & LOG_BUF_MASK,
381 __call_console_drivers(0, end & LOG_BUF_MASK);
383 __call_console_drivers(start, end);
389 * Call the console drivers, asking them to write out
390 * log_buf[start] to log_buf[end - 1].
391 * The console_sem must be held.
393 static void call_console_drivers(unsigned long start, unsigned long end)
395 unsigned long cur_index, start_print;
396 static int msg_level = -1;
398 if (((long)(start - end)) > 0)
403 while (cur_index != end) {
404 if (msg_level < 0 && ((end - cur_index) > 2) &&
405 LOG_BUF(cur_index + 0) == '<' &&
406 LOG_BUF(cur_index + 1) >= '0' &&
407 LOG_BUF(cur_index + 1) <= '7' &&
408 LOG_BUF(cur_index + 2) == '>') {
409 msg_level = LOG_BUF(cur_index + 1) - '0';
411 start_print = cur_index;
413 while (cur_index != end) {
414 char c = LOG_BUF(cur_index);
420 * printk() has already given us loglevel tags in
421 * the buffer. This code is here in case the
422 * log buffer has wrapped right round and scribbled
425 msg_level = default_message_loglevel;
427 _call_console_drivers(start_print, cur_index, msg_level);
429 start_print = cur_index;
434 _call_console_drivers(start_print, end, msg_level);
437 static void emit_log_char(char c)
439 LOG_BUF(log_end) = c;
441 if (log_end - log_start > log_buf_len)
442 log_start = log_end - log_buf_len;
443 if (log_end - con_start > log_buf_len)
444 con_start = log_end - log_buf_len;
445 if (logged_chars < log_buf_len)
450 * Zap console related locks when oopsing. Only zap at most once
451 * every 10 seconds, to leave time for slow consoles to print a
454 static void zap_locks(void)
456 static unsigned long oops_timestamp;
458 if (time_after_eq(jiffies, oops_timestamp) &&
459 !time_after(jiffies, oops_timestamp + 30 * HZ))
462 oops_timestamp = jiffies;
464 /* If a crash is occurring, make sure we can't deadlock */
465 spin_lock_init(&logbuf_lock);
466 /* And make sure that we print immediately */
467 init_MUTEX(&console_sem);
470 #if defined(CONFIG_PRINTK_TIME)
471 static int printk_time = 1;
473 static int printk_time = 0;
476 static int __init printk_time_setup(char *str)
484 __setup("time", printk_time_setup);
486 __attribute__((weak)) unsigned long long printk_clock(void)
488 return sched_clock();
492 * printk - print a kernel message
493 * @fmt: format string
495 * This is printk. It can be called from any context. We want it to work.
497 * We try to grab the console_sem. If we succeed, it's easy - we log the output and
498 * call the console drivers. If we fail to get the semaphore we place the output
499 * into the log buffer and return. The current holder of the console_sem will
500 * notice the new output in release_console_sem() and will send it to the
501 * consoles before releasing the semaphore.
503 * One effect of this deferred printing is that code which calls printk() and
504 * then changes console_loglevel may break. This is because console_loglevel
505 * is inspected when the actual printing occurs.
511 asmlinkage int printk(const char *fmt, ...)
517 r = vprintk(fmt, args);
523 /* cpu currently holding logbuf_lock */
524 static volatile unsigned int printk_cpu = UINT_MAX;
526 asmlinkage int vprintk(const char *fmt, va_list args)
531 static char printk_buf[1024];
532 static int log_level_unknown = 1;
535 if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
536 /* If a crash is occurring during printk() on this CPU,
537 * make sure we can't deadlock */
540 /* This stops the holder of console_sem just where we want him */
541 spin_lock_irqsave(&logbuf_lock, flags);
542 printk_cpu = smp_processor_id();
544 /* Emit the output into the temporary buffer */
545 printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args);
548 * Copy the output into log_buf. If the caller didn't provide
549 * appropriate log level tags, we insert them here
551 for (p = printk_buf; *p; p++) {
552 if (log_level_unknown) {
553 /* log_level_unknown signals the start of a new line */
558 unsigned long long t;
559 unsigned long nanosec_rem;
562 * force the log level token to be
563 * before the time output.
565 if (p[0] == '<' && p[1] >='0' &&
566 p[1] <= '7' && p[2] == '>') {
571 loglev_char = default_message_loglevel
575 nanosec_rem = do_div(t, 1000000000);
582 for (tp = tbuf; tp < tbuf + tlen; tp++)
586 if (p[0] != '<' || p[1] < '0' ||
587 p[1] > '7' || p[2] != '>') {
589 emit_log_char(default_message_loglevel
595 log_level_unknown = 0;
601 log_level_unknown = 1;
604 if (!cpu_online(smp_processor_id())) {
606 * Some console drivers may assume that per-cpu resources have
607 * been allocated. So don't allow them to be called by this
608 * CPU until it is officially up. We shouldn't be calling into
609 * random console drivers on a CPU which doesn't exist yet..
611 printk_cpu = UINT_MAX;
612 spin_unlock_irqrestore(&logbuf_lock, flags);
615 if (!down_trylock(&console_sem)) {
618 * We own the drivers. We can drop the spinlock and let
619 * release_console_sem() print the text
621 printk_cpu = UINT_MAX;
622 spin_unlock_irqrestore(&logbuf_lock, flags);
623 console_may_schedule = 0;
624 release_console_sem();
627 * Someone else owns the drivers. We drop the spinlock, which
628 * allows the semaphore holder to proceed and to call the
629 * console drivers with the output which we just produced.
631 printk_cpu = UINT_MAX;
632 spin_unlock_irqrestore(&logbuf_lock, flags);
638 EXPORT_SYMBOL(printk);
639 EXPORT_SYMBOL(vprintk);
643 asmlinkage long sys_syslog(int type, char __user *buf, int len)
648 int do_syslog(int type, char __user *buf, int len)
653 static void call_console_drivers(unsigned long start, unsigned long end)
660 * add_preferred_console - add a device to the list of preferred consoles.
663 * @options: options for this console
665 * The last preferred console added will be used for kernel messages
666 * and stdin/out/err for init. Normally this is used by console_setup
667 * above to handle user-supplied console arguments; however it can also
668 * be used by arch-specific code either to override the user or more
669 * commonly to provide a default console (ie from PROM variables) when
670 * the user has not supplied one.
672 int __init add_preferred_console(char *name, int idx, char *options)
674 struct console_cmdline *c;
678 * See if this tty is not yet registered, and
679 * if we have a slot free.
681 for(i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
682 if (strcmp(console_cmdline[i].name, name) == 0 &&
683 console_cmdline[i].index == idx) {
684 selected_console = i;
687 if (i == MAX_CMDLINECONSOLES)
689 selected_console = i;
690 c = &console_cmdline[i];
691 memcpy(c->name, name, sizeof(c->name));
692 c->name[sizeof(c->name) - 1] = 0;
693 c->options = options;
699 * acquire_console_sem - lock the console system for exclusive use.
701 * Acquires a semaphore which guarantees that the caller has
702 * exclusive access to the console system and the console_drivers list.
704 * Can sleep, returns nothing.
706 void acquire_console_sem(void)
712 console_may_schedule = 1;
714 EXPORT_SYMBOL(acquire_console_sem);
716 int try_acquire_console_sem(void)
718 if (down_trylock(&console_sem))
721 console_may_schedule = 0;
724 EXPORT_SYMBOL(try_acquire_console_sem);
726 int is_console_locked(void)
728 return console_locked;
730 EXPORT_SYMBOL(is_console_locked);
733 * release_console_sem - unlock the console system
735 * Releases the semaphore which the caller holds on the console system
736 * and the console driver list.
738 * While the semaphore was held, console output may have been buffered
739 * by printk(). If this is the case, release_console_sem() emits
740 * the output prior to releasing the semaphore.
742 * If there is output waiting for klogd, we wake it up.
744 * release_console_sem() may be called from any context.
746 void release_console_sem(void)
749 unsigned long _con_start, _log_end;
750 unsigned long wake_klogd = 0;
753 spin_lock_irqsave(&logbuf_lock, flags);
754 wake_klogd |= log_start - log_end;
755 if (con_start == log_end)
756 break; /* Nothing to print */
757 _con_start = con_start;
759 con_start = log_end; /* Flush */
760 spin_unlock(&logbuf_lock);
761 call_console_drivers(_con_start, _log_end);
762 local_irq_restore(flags);
765 console_may_schedule = 0;
767 spin_unlock_irqrestore(&logbuf_lock, flags);
768 if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait))
769 wake_up_interruptible(&log_wait);
771 EXPORT_SYMBOL(release_console_sem);
774 * console_conditional_schedule - yield the CPU if required
776 * If the console code is currently allowed to sleep, and
777 * if this CPU should yield the CPU to another task, do
780 * Must be called within acquire_console_sem().
782 void __sched console_conditional_schedule(void)
784 if (console_may_schedule)
787 EXPORT_SYMBOL(console_conditional_schedule);
789 void console_print(const char *s)
791 printk(KERN_EMERG "%s", s);
793 EXPORT_SYMBOL(console_print);
795 void console_unblank(void)
800 * console_unblank can no longer be called in interrupt context unless
801 * oops_in_progress is set to 1..
803 if (oops_in_progress) {
804 if (down_trylock(&console_sem) != 0)
807 acquire_console_sem();
810 console_may_schedule = 0;
811 for (c = console_drivers; c != NULL; c = c->next)
812 if ((c->flags & CON_ENABLED) && c->unblank)
814 release_console_sem();
818 * Return the console tty driver structure and its associated index
820 struct tty_driver *console_device(int *index)
823 struct tty_driver *driver = NULL;
825 acquire_console_sem();
826 for (c = console_drivers; c != NULL; c = c->next) {
829 driver = c->device(c, index);
833 release_console_sem();
838 * Prevent further output on the passed console device so that (for example)
839 * serial drivers can disable console output before suspending a port, and can
840 * re-enable output afterwards.
842 void console_stop(struct console *console)
844 acquire_console_sem();
845 console->flags &= ~CON_ENABLED;
846 release_console_sem();
848 EXPORT_SYMBOL(console_stop);
850 void console_start(struct console *console)
852 acquire_console_sem();
853 console->flags |= CON_ENABLED;
854 release_console_sem();
856 EXPORT_SYMBOL(console_start);
859 * The console driver calls this routine during kernel initialization
860 * to register the console printing procedure with printk() and to
861 * print any messages that were printed by the kernel before the
862 * console driver was initialized.
864 void register_console(struct console *console)
869 if (preferred_console < 0)
870 preferred_console = selected_console;
873 * See if we want to use this console driver. If we
874 * didn't select a console we take the first one
875 * that registers here.
877 if (preferred_console < 0) {
878 if (console->index < 0)
880 if (console->setup == NULL ||
881 console->setup(console, NULL) == 0) {
882 console->flags |= CON_ENABLED | CON_CONSDEV;
883 preferred_console = 0;
888 * See if this console matches one we selected on
891 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
893 if (strcmp(console_cmdline[i].name, console->name) != 0)
895 if (console->index >= 0 &&
896 console->index != console_cmdline[i].index)
898 if (console->index < 0)
899 console->index = console_cmdline[i].index;
900 if (console->setup &&
901 console->setup(console, console_cmdline[i].options) != 0)
903 console->flags |= CON_ENABLED;
904 console->index = console_cmdline[i].index;
905 if (i == selected_console) {
906 console->flags |= CON_CONSDEV;
907 preferred_console = selected_console;
912 if (!(console->flags & CON_ENABLED))
915 if (console_drivers && (console_drivers->flags & CON_BOOT)) {
916 unregister_console(console_drivers);
917 console->flags &= ~CON_PRINTBUFFER;
921 * Put this console in the list - keep the
922 * preferred driver at the head of the list.
924 acquire_console_sem();
925 if ((console->flags & CON_CONSDEV) || console_drivers == NULL) {
926 console->next = console_drivers;
927 console_drivers = console;
929 console->next->flags &= ~CON_CONSDEV;
931 console->next = console_drivers->next;
932 console_drivers->next = console;
934 if (console->flags & CON_PRINTBUFFER) {
936 * release_console_sem() will print out the buffered messages
939 spin_lock_irqsave(&logbuf_lock, flags);
940 con_start = log_start;
941 spin_unlock_irqrestore(&logbuf_lock, flags);
943 release_console_sem();
945 EXPORT_SYMBOL(register_console);
947 int unregister_console(struct console *console)
949 struct console *a, *b;
952 acquire_console_sem();
953 if (console_drivers == console) {
954 console_drivers=console->next;
956 } else if (console_drivers) {
957 for (a=console_drivers->next, b=console_drivers ;
967 /* If last console is removed, we re-enable picking the first
968 * one that gets registered. Without that, pmac early boot console
969 * would prevent fbcon from taking over.
971 * If this isn't the last console and it has CON_CONSDEV set, we
972 * need to set it on the next preferred console.
974 if (console_drivers == NULL)
975 preferred_console = selected_console;
976 else if (console->flags & CON_CONSDEV)
977 console_drivers->flags |= CON_CONSDEV;
979 release_console_sem();
982 EXPORT_SYMBOL(unregister_console);
985 * tty_write_message - write a message to a certain tty, not just the console.
986 * @tty: the destination tty_struct
987 * @msg: the message to write
989 * This is used for messages that need to be redirected to a specific tty.
990 * We don't put it into the syslog queue right now maybe in the future if
993 void tty_write_message(struct tty_struct *tty, char *msg)
995 if (tty && tty->driver->write)
996 tty->driver->write(tty, msg, strlen(msg));
1001 * printk rate limiting, lifted from the networking subsystem.
1003 * This enforces a rate limit: not more than one kernel message
1004 * every printk_ratelimit_jiffies to make a denial-of-service
1005 * attack impossible.
1007 int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst)
1009 static DEFINE_SPINLOCK(ratelimit_lock);
1010 static unsigned long toks = 10 * 5 * HZ;
1011 static unsigned long last_msg;
1013 unsigned long flags;
1014 unsigned long now = jiffies;
1016 spin_lock_irqsave(&ratelimit_lock, flags);
1017 toks += now - last_msg;
1019 if (toks > (ratelimit_burst * ratelimit_jiffies))
1020 toks = ratelimit_burst * ratelimit_jiffies;
1021 if (toks >= ratelimit_jiffies) {
1025 toks -= ratelimit_jiffies;
1026 spin_unlock_irqrestore(&ratelimit_lock, flags);
1028 printk(KERN_WARNING "printk: %d messages suppressed.\n", lost);
1032 spin_unlock_irqrestore(&ratelimit_lock, flags);
1035 EXPORT_SYMBOL(__printk_ratelimit);
1037 /* minimum time in jiffies between messages */
1038 int printk_ratelimit_jiffies = 5 * HZ;
1040 /* number of messages we send before ratelimiting */
1041 int printk_ratelimit_burst = 10;
1043 int printk_ratelimit(void)
1045 return __printk_ratelimit(printk_ratelimit_jiffies,
1046 printk_ratelimit_burst);
1048 EXPORT_SYMBOL(printk_ratelimit);