Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
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). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
34 | #include <linux/syscalls.h> | |
35 | ||
36 | #include <asm/uaccess.h> | |
37 | ||
076f9776 IM |
38 | /* |
39 | * Architectures can override it: | |
40 | */ | |
e17ba73b | 41 | void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) |
076f9776 IM |
42 | { |
43 | } | |
44 | ||
1da177e4 LT |
45 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
46 | ||
47 | /* printk's without a loglevel use this.. */ | |
48 | #define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */ | |
49 | ||
50 | /* We show everything that is MORE important than this.. */ | |
51 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ | |
52 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ | |
53 | ||
54 | DECLARE_WAIT_QUEUE_HEAD(log_wait); | |
55 | ||
56 | int console_printk[4] = { | |
57 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ | |
58 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ | |
59 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ | |
60 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ | |
61 | }; | |
62 | ||
1da177e4 | 63 | /* |
0bbfb7c2 | 64 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
65 | * their unblank() callback or not. So let's export it. |
66 | */ | |
67 | int oops_in_progress; | |
68 | EXPORT_SYMBOL(oops_in_progress); | |
69 | ||
70 | /* | |
71 | * console_sem protects the console_drivers list, and also | |
72 | * provides serialisation for access to the entire console | |
73 | * driver system. | |
74 | */ | |
75 | static DECLARE_MUTEX(console_sem); | |
557240b4 | 76 | static DECLARE_MUTEX(secondary_console_sem); |
1da177e4 | 77 | struct console *console_drivers; |
a29d1cfe IM |
78 | EXPORT_SYMBOL_GPL(console_drivers); |
79 | ||
1da177e4 LT |
80 | /* |
81 | * This is used for debugging the mess that is the VT code by | |
82 | * keeping track if we have the console semaphore held. It's | |
83 | * definitely not the perfect debug tool (we don't know if _WE_ | |
84 | * hold it are racing, but it helps tracking those weird code | |
85 | * path in the console code where we end up in places I want | |
86 | * locked without the console sempahore held | |
87 | */ | |
557240b4 | 88 | static int console_locked, console_suspended; |
1da177e4 LT |
89 | |
90 | /* | |
91 | * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars | |
92 | * It is also used in interesting ways to provide interlocking in | |
93 | * release_console_sem(). | |
94 | */ | |
95 | static DEFINE_SPINLOCK(logbuf_lock); | |
96 | ||
eed4a2ab | 97 | #define LOG_BUF_MASK (log_buf_len-1) |
1da177e4 LT |
98 | #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) |
99 | ||
100 | /* | |
101 | * The indices into log_buf are not constrained to log_buf_len - they | |
102 | * must be masked before subscripting | |
103 | */ | |
eed4a2ab DV |
104 | static unsigned log_start; /* Index into log_buf: next char to be read by syslog() */ |
105 | static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */ | |
106 | static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ | |
1da177e4 LT |
107 | |
108 | /* | |
109 | * Array of consoles built from command line options (console=) | |
110 | */ | |
111 | struct console_cmdline | |
112 | { | |
113 | char name[8]; /* Name of the driver */ | |
114 | int index; /* Minor dev. to use */ | |
115 | char *options; /* Options for the driver */ | |
f7511d5f ST |
116 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
117 | char *brl_options; /* Options for braille driver */ | |
118 | #endif | |
1da177e4 LT |
119 | }; |
120 | ||
121 | #define MAX_CMDLINECONSOLES 8 | |
122 | ||
123 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
124 | static int selected_console = -1; | |
125 | static int preferred_console = -1; | |
9e124fe1 MA |
126 | int console_set_on_cmdline; |
127 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
128 | |
129 | /* Flag: console code may call schedule() */ | |
130 | static int console_may_schedule; | |
131 | ||
d59745ce MM |
132 | #ifdef CONFIG_PRINTK |
133 | ||
134 | static char __log_buf[__LOG_BUF_LEN]; | |
135 | static char *log_buf = __log_buf; | |
136 | static int log_buf_len = __LOG_BUF_LEN; | |
eed4a2ab | 137 | static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ |
d59745ce | 138 | |
1da177e4 LT |
139 | static int __init log_buf_len_setup(char *str) |
140 | { | |
eed4a2ab | 141 | unsigned size = memparse(str, &str); |
1da177e4 LT |
142 | unsigned long flags; |
143 | ||
144 | if (size) | |
145 | size = roundup_pow_of_two(size); | |
146 | if (size > log_buf_len) { | |
eed4a2ab | 147 | unsigned start, dest_idx, offset; |
40dc5651 | 148 | char *new_log_buf; |
1da177e4 LT |
149 | |
150 | new_log_buf = alloc_bootmem(size); | |
151 | if (!new_log_buf) { | |
40dc5651 | 152 | printk(KERN_WARNING "log_buf_len: allocation failed\n"); |
1da177e4 LT |
153 | goto out; |
154 | } | |
155 | ||
156 | spin_lock_irqsave(&logbuf_lock, flags); | |
157 | log_buf_len = size; | |
158 | log_buf = new_log_buf; | |
159 | ||
160 | offset = start = min(con_start, log_start); | |
161 | dest_idx = 0; | |
162 | while (start != log_end) { | |
163 | log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)]; | |
164 | start++; | |
165 | dest_idx++; | |
166 | } | |
167 | log_start -= offset; | |
168 | con_start -= offset; | |
169 | log_end -= offset; | |
170 | spin_unlock_irqrestore(&logbuf_lock, flags); | |
171 | ||
40dc5651 | 172 | printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len); |
1da177e4 LT |
173 | } |
174 | out: | |
1da177e4 LT |
175 | return 1; |
176 | } | |
177 | ||
178 | __setup("log_buf_len=", log_buf_len_setup); | |
179 | ||
bfe8df3d RD |
180 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
181 | ||
182 | static unsigned int boot_delay; /* msecs delay after each printk during bootup */ | |
183 | static unsigned long long printk_delay_msec; /* per msec, based on boot_delay */ | |
184 | ||
185 | static int __init boot_delay_setup(char *str) | |
186 | { | |
187 | unsigned long lpj; | |
188 | unsigned long long loops_per_msec; | |
189 | ||
190 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
191 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
192 | ||
193 | get_option(&str, &boot_delay); | |
194 | if (boot_delay > 10 * 1000) | |
195 | boot_delay = 0; | |
196 | ||
197 | printk_delay_msec = loops_per_msec; | |
198 | printk(KERN_DEBUG "boot_delay: %u, preset_lpj: %ld, lpj: %lu, " | |
199 | "HZ: %d, printk_delay_msec: %llu\n", | |
200 | boot_delay, preset_lpj, lpj, HZ, printk_delay_msec); | |
201 | return 1; | |
202 | } | |
203 | __setup("boot_delay=", boot_delay_setup); | |
204 | ||
205 | static void boot_delay_msec(void) | |
206 | { | |
207 | unsigned long long k; | |
208 | unsigned long timeout; | |
209 | ||
210 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) | |
211 | return; | |
212 | ||
213 | k = (unsigned long long)printk_delay_msec * boot_delay; | |
214 | ||
215 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
216 | while (k) { | |
217 | k--; | |
218 | cpu_relax(); | |
219 | /* | |
220 | * use (volatile) jiffies to prevent | |
221 | * compiler reduction; loop termination via jiffies | |
222 | * is secondary and may or may not happen. | |
223 | */ | |
224 | if (time_after(jiffies, timeout)) | |
225 | break; | |
226 | touch_nmi_watchdog(); | |
227 | } | |
228 | } | |
229 | #else | |
230 | static inline void boot_delay_msec(void) | |
231 | { | |
232 | } | |
233 | #endif | |
234 | ||
1da177e4 LT |
235 | /* |
236 | * Commands to do_syslog: | |
237 | * | |
238 | * 0 -- Close the log. Currently a NOP. | |
239 | * 1 -- Open the log. Currently a NOP. | |
240 | * 2 -- Read from the log. | |
241 | * 3 -- Read all messages remaining in the ring buffer. | |
242 | * 4 -- Read and clear all messages remaining in the ring buffer | |
243 | * 5 -- Clear ring buffer. | |
244 | * 6 -- Disable printk's to console | |
245 | * 7 -- Enable printk's to console | |
246 | * 8 -- Set level of messages printed to console | |
247 | * 9 -- Return number of unread characters in the log buffer | |
248 | * 10 -- Return size of the log buffer | |
249 | */ | |
40dc5651 | 250 | int do_syslog(int type, char __user *buf, int len) |
1da177e4 | 251 | { |
eed4a2ab | 252 | unsigned i, j, limit, count; |
1da177e4 LT |
253 | int do_clear = 0; |
254 | char c; | |
255 | int error = 0; | |
256 | ||
257 | error = security_syslog(type); | |
258 | if (error) | |
259 | return error; | |
260 | ||
261 | switch (type) { | |
262 | case 0: /* Close log */ | |
263 | break; | |
264 | case 1: /* Open log */ | |
265 | break; | |
266 | case 2: /* Read from log */ | |
267 | error = -EINVAL; | |
268 | if (!buf || len < 0) | |
269 | goto out; | |
270 | error = 0; | |
271 | if (!len) | |
272 | goto out; | |
273 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
274 | error = -EFAULT; | |
275 | goto out; | |
276 | } | |
40dc5651 JJ |
277 | error = wait_event_interruptible(log_wait, |
278 | (log_start - log_end)); | |
1da177e4 LT |
279 | if (error) |
280 | goto out; | |
281 | i = 0; | |
282 | spin_lock_irq(&logbuf_lock); | |
283 | while (!error && (log_start != log_end) && i < len) { | |
284 | c = LOG_BUF(log_start); | |
285 | log_start++; | |
286 | spin_unlock_irq(&logbuf_lock); | |
287 | error = __put_user(c,buf); | |
288 | buf++; | |
289 | i++; | |
290 | cond_resched(); | |
291 | spin_lock_irq(&logbuf_lock); | |
292 | } | |
293 | spin_unlock_irq(&logbuf_lock); | |
294 | if (!error) | |
295 | error = i; | |
296 | break; | |
297 | case 4: /* Read/clear last kernel messages */ | |
40dc5651 | 298 | do_clear = 1; |
1da177e4 LT |
299 | /* FALL THRU */ |
300 | case 3: /* Read last kernel messages */ | |
301 | error = -EINVAL; | |
302 | if (!buf || len < 0) | |
303 | goto out; | |
304 | error = 0; | |
305 | if (!len) | |
306 | goto out; | |
307 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
308 | error = -EFAULT; | |
309 | goto out; | |
310 | } | |
311 | count = len; | |
312 | if (count > log_buf_len) | |
313 | count = log_buf_len; | |
314 | spin_lock_irq(&logbuf_lock); | |
315 | if (count > logged_chars) | |
316 | count = logged_chars; | |
317 | if (do_clear) | |
318 | logged_chars = 0; | |
319 | limit = log_end; | |
320 | /* | |
321 | * __put_user() could sleep, and while we sleep | |
40dc5651 | 322 | * printk() could overwrite the messages |
1da177e4 LT |
323 | * we try to copy to user space. Therefore |
324 | * the messages are copied in reverse. <manfreds> | |
325 | */ | |
40dc5651 | 326 | for (i = 0; i < count && !error; i++) { |
1da177e4 LT |
327 | j = limit-1-i; |
328 | if (j + log_buf_len < log_end) | |
329 | break; | |
330 | c = LOG_BUF(j); | |
331 | spin_unlock_irq(&logbuf_lock); | |
332 | error = __put_user(c,&buf[count-1-i]); | |
333 | cond_resched(); | |
334 | spin_lock_irq(&logbuf_lock); | |
335 | } | |
336 | spin_unlock_irq(&logbuf_lock); | |
337 | if (error) | |
338 | break; | |
339 | error = i; | |
40dc5651 | 340 | if (i != count) { |
1da177e4 LT |
341 | int offset = count-error; |
342 | /* buffer overflow during copy, correct user buffer. */ | |
40dc5651 | 343 | for (i = 0; i < error; i++) { |
1da177e4 LT |
344 | if (__get_user(c,&buf[i+offset]) || |
345 | __put_user(c,&buf[i])) { | |
346 | error = -EFAULT; | |
347 | break; | |
348 | } | |
349 | cond_resched(); | |
350 | } | |
351 | } | |
352 | break; | |
353 | case 5: /* Clear ring buffer */ | |
354 | logged_chars = 0; | |
355 | break; | |
356 | case 6: /* Disable logging to console */ | |
357 | console_loglevel = minimum_console_loglevel; | |
358 | break; | |
359 | case 7: /* Enable logging to console */ | |
360 | console_loglevel = default_console_loglevel; | |
361 | break; | |
362 | case 8: /* Set level of messages printed to console */ | |
363 | error = -EINVAL; | |
364 | if (len < 1 || len > 8) | |
365 | goto out; | |
366 | if (len < minimum_console_loglevel) | |
367 | len = minimum_console_loglevel; | |
368 | console_loglevel = len; | |
369 | error = 0; | |
370 | break; | |
371 | case 9: /* Number of chars in the log buffer */ | |
372 | error = log_end - log_start; | |
373 | break; | |
374 | case 10: /* Size of the log buffer */ | |
375 | error = log_buf_len; | |
376 | break; | |
377 | default: | |
378 | error = -EINVAL; | |
379 | break; | |
380 | } | |
381 | out: | |
382 | return error; | |
383 | } | |
384 | ||
1e7bfb21 | 385 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 LT |
386 | { |
387 | return do_syslog(type, buf, len); | |
388 | } | |
389 | ||
390 | /* | |
391 | * Call the console drivers on a range of log_buf | |
392 | */ | |
eed4a2ab | 393 | static void __call_console_drivers(unsigned start, unsigned end) |
1da177e4 LT |
394 | { |
395 | struct console *con; | |
396 | ||
397 | for (con = console_drivers; con; con = con->next) { | |
76a8ad29 ME |
398 | if ((con->flags & CON_ENABLED) && con->write && |
399 | (cpu_online(smp_processor_id()) || | |
400 | (con->flags & CON_ANYTIME))) | |
1da177e4 LT |
401 | con->write(con, &LOG_BUF(start), end - start); |
402 | } | |
403 | } | |
404 | ||
79290822 IM |
405 | static int __read_mostly ignore_loglevel; |
406 | ||
99eea6a1 | 407 | static int __init ignore_loglevel_setup(char *str) |
79290822 IM |
408 | { |
409 | ignore_loglevel = 1; | |
410 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); | |
411 | ||
c4772d99 | 412 | return 0; |
79290822 IM |
413 | } |
414 | ||
c4772d99 | 415 | early_param("ignore_loglevel", ignore_loglevel_setup); |
79290822 | 416 | |
1da177e4 LT |
417 | /* |
418 | * Write out chars from start to end - 1 inclusive | |
419 | */ | |
eed4a2ab DV |
420 | static void _call_console_drivers(unsigned start, |
421 | unsigned end, int msg_log_level) | |
1da177e4 | 422 | { |
79290822 | 423 | if ((msg_log_level < console_loglevel || ignore_loglevel) && |
1da177e4 LT |
424 | console_drivers && start != end) { |
425 | if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) { | |
426 | /* wrapped write */ | |
427 | __call_console_drivers(start & LOG_BUF_MASK, | |
428 | log_buf_len); | |
429 | __call_console_drivers(0, end & LOG_BUF_MASK); | |
430 | } else { | |
431 | __call_console_drivers(start, end); | |
432 | } | |
433 | } | |
434 | } | |
435 | ||
436 | /* | |
437 | * Call the console drivers, asking them to write out | |
438 | * log_buf[start] to log_buf[end - 1]. | |
439 | * The console_sem must be held. | |
440 | */ | |
eed4a2ab | 441 | static void call_console_drivers(unsigned start, unsigned end) |
1da177e4 | 442 | { |
eed4a2ab | 443 | unsigned cur_index, start_print; |
1da177e4 LT |
444 | static int msg_level = -1; |
445 | ||
eed4a2ab | 446 | BUG_ON(((int)(start - end)) > 0); |
1da177e4 LT |
447 | |
448 | cur_index = start; | |
449 | start_print = start; | |
450 | while (cur_index != end) { | |
40dc5651 JJ |
451 | if (msg_level < 0 && ((end - cur_index) > 2) && |
452 | LOG_BUF(cur_index + 0) == '<' && | |
453 | LOG_BUF(cur_index + 1) >= '0' && | |
454 | LOG_BUF(cur_index + 1) <= '7' && | |
455 | LOG_BUF(cur_index + 2) == '>') { | |
1da177e4 LT |
456 | msg_level = LOG_BUF(cur_index + 1) - '0'; |
457 | cur_index += 3; | |
458 | start_print = cur_index; | |
459 | } | |
460 | while (cur_index != end) { | |
461 | char c = LOG_BUF(cur_index); | |
1da177e4 | 462 | |
40dc5651 | 463 | cur_index++; |
1da177e4 LT |
464 | if (c == '\n') { |
465 | if (msg_level < 0) { | |
466 | /* | |
467 | * printk() has already given us loglevel tags in | |
468 | * the buffer. This code is here in case the | |
469 | * log buffer has wrapped right round and scribbled | |
470 | * on those tags | |
471 | */ | |
472 | msg_level = default_message_loglevel; | |
473 | } | |
474 | _call_console_drivers(start_print, cur_index, msg_level); | |
475 | msg_level = -1; | |
476 | start_print = cur_index; | |
477 | break; | |
478 | } | |
479 | } | |
480 | } | |
481 | _call_console_drivers(start_print, end, msg_level); | |
482 | } | |
483 | ||
484 | static void emit_log_char(char c) | |
485 | { | |
486 | LOG_BUF(log_end) = c; | |
487 | log_end++; | |
488 | if (log_end - log_start > log_buf_len) | |
489 | log_start = log_end - log_buf_len; | |
490 | if (log_end - con_start > log_buf_len) | |
491 | con_start = log_end - log_buf_len; | |
492 | if (logged_chars < log_buf_len) | |
493 | logged_chars++; | |
494 | } | |
495 | ||
496 | /* | |
497 | * Zap console related locks when oopsing. Only zap at most once | |
498 | * every 10 seconds, to leave time for slow consoles to print a | |
499 | * full oops. | |
500 | */ | |
501 | static void zap_locks(void) | |
502 | { | |
503 | static unsigned long oops_timestamp; | |
504 | ||
505 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 506 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
507 | return; |
508 | ||
509 | oops_timestamp = jiffies; | |
510 | ||
511 | /* If a crash is occurring, make sure we can't deadlock */ | |
512 | spin_lock_init(&logbuf_lock); | |
513 | /* And make sure that we print immediately */ | |
514 | init_MUTEX(&console_sem); | |
515 | } | |
516 | ||
517 | #if defined(CONFIG_PRINTK_TIME) | |
518 | static int printk_time = 1; | |
519 | #else | |
520 | static int printk_time = 0; | |
521 | #endif | |
e84845c4 | 522 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
1da177e4 | 523 | |
76a8ad29 ME |
524 | /* Check if we have any console registered that can be called early in boot. */ |
525 | static int have_callable_console(void) | |
526 | { | |
527 | struct console *con; | |
528 | ||
529 | for (con = console_drivers; con; con = con->next) | |
530 | if (con->flags & CON_ANYTIME) | |
531 | return 1; | |
532 | ||
533 | return 0; | |
534 | } | |
535 | ||
ddad86c2 MW |
536 | /** |
537 | * printk - print a kernel message | |
538 | * @fmt: format string | |
539 | * | |
72fd4a35 | 540 | * This is printk(). It can be called from any context. We want it to work. |
40dc5651 | 541 | * |
1da177e4 LT |
542 | * We try to grab the console_sem. If we succeed, it's easy - we log the output and |
543 | * call the console drivers. If we fail to get the semaphore we place the output | |
544 | * into the log buffer and return. The current holder of the console_sem will | |
545 | * notice the new output in release_console_sem() and will send it to the | |
546 | * consoles before releasing the semaphore. | |
547 | * | |
548 | * One effect of this deferred printing is that code which calls printk() and | |
549 | * then changes console_loglevel may break. This is because console_loglevel | |
550 | * is inspected when the actual printing occurs. | |
ddad86c2 MW |
551 | * |
552 | * See also: | |
553 | * printf(3) | |
20036fdc AK |
554 | * |
555 | * See the vsnprintf() documentation for format string extensions over C99. | |
1da177e4 | 556 | */ |
d59745ce | 557 | |
1da177e4 LT |
558 | asmlinkage int printk(const char *fmt, ...) |
559 | { | |
560 | va_list args; | |
561 | int r; | |
562 | ||
563 | va_start(args, fmt); | |
564 | r = vprintk(fmt, args); | |
565 | va_end(args); | |
566 | ||
567 | return r; | |
568 | } | |
569 | ||
fe21773d DH |
570 | /* cpu currently holding logbuf_lock */ |
571 | static volatile unsigned int printk_cpu = UINT_MAX; | |
572 | ||
266c2e0a LT |
573 | /* |
574 | * Can we actually use the console at this time on this cpu? | |
575 | * | |
576 | * Console drivers may assume that per-cpu resources have | |
577 | * been allocated. So unless they're explicitly marked as | |
578 | * being able to cope (CON_ANYTIME) don't call them until | |
579 | * this CPU is officially up. | |
580 | */ | |
581 | static inline int can_use_console(unsigned int cpu) | |
582 | { | |
583 | return cpu_online(cpu) || have_callable_console(); | |
584 | } | |
585 | ||
586 | /* | |
587 | * Try to get console ownership to actually show the kernel | |
588 | * messages from a 'printk'. Return true (and with the | |
589 | * console_semaphore held, and 'console_locked' set) if it | |
590 | * is successful, false otherwise. | |
591 | * | |
592 | * This gets called with the 'logbuf_lock' spinlock held and | |
593 | * interrupts disabled. It should return with 'lockbuf_lock' | |
594 | * released but interrupts still disabled. | |
595 | */ | |
596 | static int acquire_console_semaphore_for_printk(unsigned int cpu) | |
597 | { | |
598 | int retval = 0; | |
599 | ||
093a07e2 LT |
600 | if (!try_acquire_console_sem()) { |
601 | retval = 1; | |
602 | ||
603 | /* | |
604 | * If we can't use the console, we need to release | |
605 | * the console semaphore by hand to avoid flushing | |
606 | * the buffer. We need to hold the console semaphore | |
607 | * in order to do this test safely. | |
608 | */ | |
609 | if (!can_use_console(cpu)) { | |
610 | console_locked = 0; | |
611 | up(&console_sem); | |
612 | retval = 0; | |
613 | } | |
614 | } | |
266c2e0a LT |
615 | printk_cpu = UINT_MAX; |
616 | spin_unlock(&logbuf_lock); | |
617 | return retval; | |
618 | } | |
3b8945e8 TH |
619 | static const char recursion_bug_msg [] = |
620 | KERN_CRIT "BUG: recent printk recursion!\n"; | |
621 | static int recursion_bug; | |
edb123e1 | 622 | static int new_text_line = 1; |
3b8945e8 | 623 | static char printk_buf[1024]; |
32a76006 | 624 | |
1da177e4 LT |
625 | asmlinkage int vprintk(const char *fmt, va_list args) |
626 | { | |
32a76006 | 627 | int printed_len = 0; |
09159308 | 628 | int current_log_level = default_message_loglevel; |
ac60ad74 | 629 | unsigned long flags; |
32a76006 | 630 | int this_cpu; |
1da177e4 | 631 | char *p; |
1da177e4 | 632 | |
bfe8df3d RD |
633 | boot_delay_msec(); |
634 | ||
fe21773d | 635 | preempt_disable(); |
1da177e4 | 636 | /* This stops the holder of console_sem just where we want him */ |
1efc5da3 | 637 | raw_local_irq_save(flags); |
32a76006 IM |
638 | this_cpu = smp_processor_id(); |
639 | ||
640 | /* | |
641 | * Ouch, printk recursed into itself! | |
642 | */ | |
643 | if (unlikely(printk_cpu == this_cpu)) { | |
644 | /* | |
645 | * If a crash is occurring during printk() on this CPU, | |
646 | * then try to get the crash message out but make sure | |
647 | * we can't deadlock. Otherwise just return to avoid the | |
648 | * recursion and return - but flag the recursion so that | |
649 | * it can be printed at the next appropriate moment: | |
650 | */ | |
651 | if (!oops_in_progress) { | |
3b8945e8 | 652 | recursion_bug = 1; |
32a76006 IM |
653 | goto out_restore_irqs; |
654 | } | |
655 | zap_locks(); | |
656 | } | |
657 | ||
a0f1ccfd IM |
658 | lockdep_off(); |
659 | spin_lock(&logbuf_lock); | |
32a76006 | 660 | printk_cpu = this_cpu; |
1da177e4 | 661 | |
3b8945e8 TH |
662 | if (recursion_bug) { |
663 | recursion_bug = 0; | |
664 | strcpy(printk_buf, recursion_bug_msg); | |
26cc271d | 665 | printed_len = strlen(recursion_bug_msg); |
32a76006 | 666 | } |
1da177e4 | 667 | /* Emit the output into the temporary buffer */ |
32a76006 | 668 | printed_len += vscnprintf(printk_buf + printed_len, |
cf3680b9 | 669 | sizeof(printk_buf) - printed_len, fmt, args); |
1da177e4 | 670 | |
ac60ad74 | 671 | |
1da177e4 LT |
672 | /* |
673 | * Copy the output into log_buf. If the caller didn't provide | |
674 | * appropriate log level tags, we insert them here | |
675 | */ | |
676 | for (p = printk_buf; *p; p++) { | |
ac60ad74 | 677 | if (new_text_line) { |
ac60ad74 NA |
678 | /* If a token, set current_log_level and skip over */ |
679 | if (p[0] == '<' && p[1] >= '0' && p[1] <= '7' && | |
680 | p[2] == '>') { | |
681 | current_log_level = p[1] - '0'; | |
682 | p += 3; | |
683 | printed_len -= 3; | |
684 | } | |
685 | ||
686 | /* Always output the token */ | |
687 | emit_log_char('<'); | |
688 | emit_log_char(current_log_level + '0'); | |
689 | emit_log_char('>'); | |
690 | printed_len += 3; | |
691 | new_text_line = 0; | |
692 | ||
1da177e4 | 693 | if (printk_time) { |
ac60ad74 | 694 | /* Follow the token with the time */ |
1da177e4 LT |
695 | char tbuf[50], *tp; |
696 | unsigned tlen; | |
697 | unsigned long long t; | |
698 | unsigned long nanosec_rem; | |
699 | ||
326e96b9 | 700 | t = cpu_clock(printk_cpu); |
1da177e4 | 701 | nanosec_rem = do_div(t, 1000000000); |
ac60ad74 NA |
702 | tlen = sprintf(tbuf, "[%5lu.%06lu] ", |
703 | (unsigned long) t, | |
704 | nanosec_rem / 1000); | |
1da177e4 LT |
705 | |
706 | for (tp = tbuf; tp < tbuf + tlen; tp++) | |
707 | emit_log_char(*tp); | |
025510cd | 708 | printed_len += tlen; |
1da177e4 | 709 | } |
ac60ad74 | 710 | |
1da177e4 LT |
711 | if (!*p) |
712 | break; | |
713 | } | |
ac60ad74 | 714 | |
1da177e4 LT |
715 | emit_log_char(*p); |
716 | if (*p == '\n') | |
ac60ad74 | 717 | new_text_line = 1; |
1da177e4 LT |
718 | } |
719 | ||
266c2e0a LT |
720 | /* |
721 | * Try to acquire and then immediately release the | |
722 | * console semaphore. The release will do all the | |
723 | * actual magic (print out buffers, wake up klogd, | |
724 | * etc). | |
725 | * | |
726 | * The acquire_console_semaphore_for_printk() function | |
727 | * will release 'logbuf_lock' regardless of whether it | |
728 | * actually gets the semaphore or not. | |
729 | */ | |
730 | if (acquire_console_semaphore_for_printk(this_cpu)) | |
731 | release_console_sem(); | |
76a8ad29 | 732 | |
266c2e0a | 733 | lockdep_on(); |
32a76006 | 734 | out_restore_irqs: |
266c2e0a | 735 | raw_local_irq_restore(flags); |
76a8ad29 | 736 | |
fe21773d | 737 | preempt_enable(); |
1da177e4 LT |
738 | return printed_len; |
739 | } | |
740 | EXPORT_SYMBOL(printk); | |
741 | EXPORT_SYMBOL(vprintk); | |
742 | ||
d59745ce MM |
743 | #else |
744 | ||
eed4a2ab | 745 | static void call_console_drivers(unsigned start, unsigned end) |
40dc5651 JJ |
746 | { |
747 | } | |
d59745ce MM |
748 | |
749 | #endif | |
750 | ||
f7511d5f ST |
751 | static int __add_preferred_console(char *name, int idx, char *options, |
752 | char *brl_options) | |
753 | { | |
754 | struct console_cmdline *c; | |
755 | int i; | |
756 | ||
757 | /* | |
758 | * See if this tty is not yet registered, and | |
759 | * if we have a slot free. | |
760 | */ | |
761 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
762 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
763 | console_cmdline[i].index == idx) { | |
764 | if (!brl_options) | |
765 | selected_console = i; | |
766 | return 0; | |
767 | } | |
768 | if (i == MAX_CMDLINECONSOLES) | |
769 | return -E2BIG; | |
770 | if (!brl_options) | |
771 | selected_console = i; | |
772 | c = &console_cmdline[i]; | |
773 | strlcpy(c->name, name, sizeof(c->name)); | |
774 | c->options = options; | |
775 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE | |
776 | c->brl_options = brl_options; | |
777 | #endif | |
778 | c->index = idx; | |
779 | return 0; | |
780 | } | |
2ea1c539 JB |
781 | /* |
782 | * Set up a list of consoles. Called from init/main.c | |
783 | */ | |
784 | static int __init console_setup(char *str) | |
785 | { | |
eaa944af | 786 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 787 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
788 | int idx; |
789 | ||
f7511d5f ST |
790 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
791 | if (!memcmp(str, "brl,", 4)) { | |
792 | brl_options = ""; | |
793 | str += 4; | |
794 | } else if (!memcmp(str, "brl=", 4)) { | |
795 | brl_options = str + 4; | |
796 | str = strchr(brl_options, ','); | |
797 | if (!str) { | |
798 | printk(KERN_ERR "need port name after brl=\n"); | |
799 | return 1; | |
800 | } | |
801 | *(str++) = 0; | |
802 | } | |
803 | #endif | |
804 | ||
2ea1c539 JB |
805 | /* |
806 | * Decode str into name, index, options. | |
807 | */ | |
808 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
809 | strcpy(buf, "ttyS"); |
810 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 811 | } else { |
eaa944af | 812 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 813 | } |
eaa944af | 814 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
815 | if ((options = strchr(str, ',')) != NULL) |
816 | *(options++) = 0; | |
817 | #ifdef __sparc__ | |
818 | if (!strcmp(str, "ttya")) | |
eaa944af | 819 | strcpy(buf, "ttyS0"); |
2ea1c539 | 820 | if (!strcmp(str, "ttyb")) |
eaa944af | 821 | strcpy(buf, "ttyS1"); |
2ea1c539 | 822 | #endif |
eaa944af | 823 | for (s = buf; *s; s++) |
2ea1c539 JB |
824 | if ((*s >= '0' && *s <= '9') || *s == ',') |
825 | break; | |
826 | idx = simple_strtoul(s, NULL, 10); | |
827 | *s = 0; | |
828 | ||
f7511d5f | 829 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 830 | console_set_on_cmdline = 1; |
2ea1c539 JB |
831 | return 1; |
832 | } | |
833 | __setup("console=", console_setup); | |
834 | ||
3c0547ba MM |
835 | /** |
836 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
837 | * @name: device name |
838 | * @idx: device index | |
839 | * @options: options for this console | |
3c0547ba MM |
840 | * |
841 | * The last preferred console added will be used for kernel messages | |
842 | * and stdin/out/err for init. Normally this is used by console_setup | |
843 | * above to handle user-supplied console arguments; however it can also | |
844 | * be used by arch-specific code either to override the user or more | |
845 | * commonly to provide a default console (ie from PROM variables) when | |
846 | * the user has not supplied one. | |
847 | */ | |
fb445ee5 | 848 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 849 | { |
f7511d5f | 850 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
851 | } |
852 | ||
b6b1d877 | 853 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
854 | { |
855 | struct console_cmdline *c; | |
856 | int i; | |
857 | ||
858 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
859 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
860 | console_cmdline[i].index == idx) { | |
861 | c = &console_cmdline[i]; | |
f735295b | 862 | strlcpy(c->name, name_new, sizeof(c->name)); |
18a8bd94 YL |
863 | c->name[sizeof(c->name) - 1] = 0; |
864 | c->options = options; | |
865 | c->index = idx_new; | |
866 | return i; | |
867 | } | |
868 | /* not found */ | |
869 | return -1; | |
870 | } | |
871 | ||
8f4ce8c3 AS |
872 | int console_suspend_enabled = 1; |
873 | EXPORT_SYMBOL(console_suspend_enabled); | |
874 | ||
875 | static int __init console_suspend_disable(char *str) | |
876 | { | |
877 | console_suspend_enabled = 0; | |
878 | return 1; | |
879 | } | |
880 | __setup("no_console_suspend", console_suspend_disable); | |
881 | ||
557240b4 LT |
882 | /** |
883 | * suspend_console - suspend the console subsystem | |
884 | * | |
885 | * This disables printk() while we go into suspend states | |
886 | */ | |
887 | void suspend_console(void) | |
888 | { | |
8f4ce8c3 AS |
889 | if (!console_suspend_enabled) |
890 | return; | |
0d63081d | 891 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
557240b4 LT |
892 | acquire_console_sem(); |
893 | console_suspended = 1; | |
894 | } | |
895 | ||
896 | void resume_console(void) | |
897 | { | |
8f4ce8c3 AS |
898 | if (!console_suspend_enabled) |
899 | return; | |
557240b4 LT |
900 | console_suspended = 0; |
901 | release_console_sem(); | |
902 | } | |
903 | ||
1da177e4 LT |
904 | /** |
905 | * acquire_console_sem - lock the console system for exclusive use. | |
906 | * | |
907 | * Acquires a semaphore which guarantees that the caller has | |
908 | * exclusive access to the console system and the console_drivers list. | |
909 | * | |
910 | * Can sleep, returns nothing. | |
911 | */ | |
912 | void acquire_console_sem(void) | |
913 | { | |
8abd8e29 | 914 | BUG_ON(in_interrupt()); |
557240b4 LT |
915 | if (console_suspended) { |
916 | down(&secondary_console_sem); | |
917 | return; | |
918 | } | |
1da177e4 LT |
919 | down(&console_sem); |
920 | console_locked = 1; | |
921 | console_may_schedule = 1; | |
922 | } | |
923 | EXPORT_SYMBOL(acquire_console_sem); | |
924 | ||
925 | int try_acquire_console_sem(void) | |
926 | { | |
927 | if (down_trylock(&console_sem)) | |
928 | return -1; | |
929 | console_locked = 1; | |
930 | console_may_schedule = 0; | |
931 | return 0; | |
932 | } | |
933 | EXPORT_SYMBOL(try_acquire_console_sem); | |
934 | ||
935 | int is_console_locked(void) | |
936 | { | |
937 | return console_locked; | |
938 | } | |
1da177e4 | 939 | |
b845b517 PZ |
940 | static DEFINE_PER_CPU(int, printk_pending); |
941 | ||
942 | void printk_tick(void) | |
e3e8a75d | 943 | { |
b845b517 PZ |
944 | if (__get_cpu_var(printk_pending)) { |
945 | __get_cpu_var(printk_pending) = 0; | |
e3e8a75d | 946 | wake_up_interruptible(&log_wait); |
b845b517 PZ |
947 | } |
948 | } | |
949 | ||
950 | int printk_needs_cpu(int cpu) | |
951 | { | |
952 | return per_cpu(printk_pending, cpu); | |
953 | } | |
954 | ||
955 | void wake_up_klogd(void) | |
956 | { | |
957 | if (waitqueue_active(&log_wait)) | |
fa33507a | 958 | __raw_get_cpu_var(printk_pending) = 1; |
e3e8a75d KK |
959 | } |
960 | ||
1da177e4 LT |
961 | /** |
962 | * release_console_sem - unlock the console system | |
963 | * | |
964 | * Releases the semaphore which the caller holds on the console system | |
965 | * and the console driver list. | |
966 | * | |
967 | * While the semaphore was held, console output may have been buffered | |
968 | * by printk(). If this is the case, release_console_sem() emits | |
969 | * the output prior to releasing the semaphore. | |
970 | * | |
971 | * If there is output waiting for klogd, we wake it up. | |
972 | * | |
973 | * release_console_sem() may be called from any context. | |
974 | */ | |
975 | void release_console_sem(void) | |
976 | { | |
977 | unsigned long flags; | |
eed4a2ab DV |
978 | unsigned _con_start, _log_end; |
979 | unsigned wake_klogd = 0; | |
1da177e4 | 980 | |
557240b4 LT |
981 | if (console_suspended) { |
982 | up(&secondary_console_sem); | |
983 | return; | |
984 | } | |
78944e54 AD |
985 | |
986 | console_may_schedule = 0; | |
987 | ||
1da177e4 LT |
988 | for ( ; ; ) { |
989 | spin_lock_irqsave(&logbuf_lock, flags); | |
990 | wake_klogd |= log_start - log_end; | |
991 | if (con_start == log_end) | |
992 | break; /* Nothing to print */ | |
993 | _con_start = con_start; | |
994 | _log_end = log_end; | |
995 | con_start = log_end; /* Flush */ | |
996 | spin_unlock(&logbuf_lock); | |
81d68a96 | 997 | stop_critical_timings(); /* don't trace print latency */ |
1da177e4 | 998 | call_console_drivers(_con_start, _log_end); |
81d68a96 | 999 | start_critical_timings(); |
1da177e4 LT |
1000 | local_irq_restore(flags); |
1001 | } | |
1002 | console_locked = 0; | |
1da177e4 LT |
1003 | up(&console_sem); |
1004 | spin_unlock_irqrestore(&logbuf_lock, flags); | |
e3e8a75d KK |
1005 | if (wake_klogd) |
1006 | wake_up_klogd(); | |
1da177e4 LT |
1007 | } |
1008 | EXPORT_SYMBOL(release_console_sem); | |
1009 | ||
ddad86c2 MW |
1010 | /** |
1011 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
1012 | * |
1013 | * If the console code is currently allowed to sleep, and | |
1014 | * if this CPU should yield the CPU to another task, do | |
1015 | * so here. | |
1016 | * | |
1017 | * Must be called within acquire_console_sem(). | |
1018 | */ | |
1019 | void __sched console_conditional_schedule(void) | |
1020 | { | |
1021 | if (console_may_schedule) | |
1022 | cond_resched(); | |
1023 | } | |
1024 | EXPORT_SYMBOL(console_conditional_schedule); | |
1025 | ||
1026 | void console_print(const char *s) | |
1027 | { | |
1028 | printk(KERN_EMERG "%s", s); | |
1029 | } | |
1030 | EXPORT_SYMBOL(console_print); | |
1031 | ||
1032 | void console_unblank(void) | |
1033 | { | |
1034 | struct console *c; | |
1035 | ||
1036 | /* | |
1037 | * console_unblank can no longer be called in interrupt context unless | |
1038 | * oops_in_progress is set to 1.. | |
1039 | */ | |
1040 | if (oops_in_progress) { | |
1041 | if (down_trylock(&console_sem) != 0) | |
1042 | return; | |
1043 | } else | |
1044 | acquire_console_sem(); | |
1045 | ||
1046 | console_locked = 1; | |
1047 | console_may_schedule = 0; | |
1048 | for (c = console_drivers; c != NULL; c = c->next) | |
1049 | if ((c->flags & CON_ENABLED) && c->unblank) | |
1050 | c->unblank(); | |
1051 | release_console_sem(); | |
1052 | } | |
1da177e4 LT |
1053 | |
1054 | /* | |
1055 | * Return the console tty driver structure and its associated index | |
1056 | */ | |
1057 | struct tty_driver *console_device(int *index) | |
1058 | { | |
1059 | struct console *c; | |
1060 | struct tty_driver *driver = NULL; | |
1061 | ||
1062 | acquire_console_sem(); | |
1063 | for (c = console_drivers; c != NULL; c = c->next) { | |
1064 | if (!c->device) | |
1065 | continue; | |
1066 | driver = c->device(c, index); | |
1067 | if (driver) | |
1068 | break; | |
1069 | } | |
1070 | release_console_sem(); | |
1071 | return driver; | |
1072 | } | |
1073 | ||
1074 | /* | |
1075 | * Prevent further output on the passed console device so that (for example) | |
1076 | * serial drivers can disable console output before suspending a port, and can | |
1077 | * re-enable output afterwards. | |
1078 | */ | |
1079 | void console_stop(struct console *console) | |
1080 | { | |
1081 | acquire_console_sem(); | |
1082 | console->flags &= ~CON_ENABLED; | |
1083 | release_console_sem(); | |
1084 | } | |
1085 | EXPORT_SYMBOL(console_stop); | |
1086 | ||
1087 | void console_start(struct console *console) | |
1088 | { | |
1089 | acquire_console_sem(); | |
1090 | console->flags |= CON_ENABLED; | |
1091 | release_console_sem(); | |
1092 | } | |
1093 | EXPORT_SYMBOL(console_start); | |
1094 | ||
1095 | /* | |
1096 | * The console driver calls this routine during kernel initialization | |
1097 | * to register the console printing procedure with printk() and to | |
1098 | * print any messages that were printed by the kernel before the | |
1099 | * console driver was initialized. | |
1100 | */ | |
40dc5651 | 1101 | void register_console(struct console *console) |
1da177e4 | 1102 | { |
40dc5651 | 1103 | int i; |
1da177e4 | 1104 | unsigned long flags; |
69331af7 | 1105 | struct console *bootconsole = NULL; |
1da177e4 | 1106 | |
69331af7 GH |
1107 | if (console_drivers) { |
1108 | if (console->flags & CON_BOOT) | |
1109 | return; | |
1110 | if (console_drivers->flags & CON_BOOT) | |
1111 | bootconsole = console_drivers; | |
1112 | } | |
1113 | ||
1114 | if (preferred_console < 0 || bootconsole || !console_drivers) | |
1da177e4 LT |
1115 | preferred_console = selected_console; |
1116 | ||
18a8bd94 YL |
1117 | if (console->early_setup) |
1118 | console->early_setup(); | |
1119 | ||
1da177e4 LT |
1120 | /* |
1121 | * See if we want to use this console driver. If we | |
1122 | * didn't select a console we take the first one | |
1123 | * that registers here. | |
1124 | */ | |
1125 | if (preferred_console < 0) { | |
1126 | if (console->index < 0) | |
1127 | console->index = 0; | |
1128 | if (console->setup == NULL || | |
1129 | console->setup(console, NULL) == 0) { | |
cd3a1b85 JK |
1130 | console->flags |= CON_ENABLED; |
1131 | if (console->device) { | |
1132 | console->flags |= CON_CONSDEV; | |
1133 | preferred_console = 0; | |
1134 | } | |
1da177e4 LT |
1135 | } |
1136 | } | |
1137 | ||
1138 | /* | |
1139 | * See if this console matches one we selected on | |
1140 | * the command line. | |
1141 | */ | |
40dc5651 JJ |
1142 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
1143 | i++) { | |
1da177e4 LT |
1144 | if (strcmp(console_cmdline[i].name, console->name) != 0) |
1145 | continue; | |
1146 | if (console->index >= 0 && | |
1147 | console->index != console_cmdline[i].index) | |
1148 | continue; | |
1149 | if (console->index < 0) | |
1150 | console->index = console_cmdline[i].index; | |
f7511d5f ST |
1151 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1152 | if (console_cmdline[i].brl_options) { | |
1153 | console->flags |= CON_BRL; | |
1154 | braille_register_console(console, | |
1155 | console_cmdline[i].index, | |
1156 | console_cmdline[i].options, | |
1157 | console_cmdline[i].brl_options); | |
1158 | return; | |
1159 | } | |
1160 | #endif | |
1da177e4 LT |
1161 | if (console->setup && |
1162 | console->setup(console, console_cmdline[i].options) != 0) | |
1163 | break; | |
1164 | console->flags |= CON_ENABLED; | |
1165 | console->index = console_cmdline[i].index; | |
ab4af03a | 1166 | if (i == selected_console) { |
1da177e4 | 1167 | console->flags |= CON_CONSDEV; |
ab4af03a GE |
1168 | preferred_console = selected_console; |
1169 | } | |
1da177e4 LT |
1170 | break; |
1171 | } | |
1172 | ||
1173 | if (!(console->flags & CON_ENABLED)) | |
1174 | return; | |
1175 | ||
d37bf60d | 1176 | if (bootconsole && (console->flags & CON_CONSDEV)) { |
69331af7 GH |
1177 | printk(KERN_INFO "console handover: boot [%s%d] -> real [%s%d]\n", |
1178 | bootconsole->name, bootconsole->index, | |
1179 | console->name, console->index); | |
1180 | unregister_console(bootconsole); | |
1da177e4 | 1181 | console->flags &= ~CON_PRINTBUFFER; |
d37bf60d YL |
1182 | } else { |
1183 | printk(KERN_INFO "console [%s%d] enabled\n", | |
1184 | console->name, console->index); | |
1da177e4 LT |
1185 | } |
1186 | ||
1187 | /* | |
1188 | * Put this console in the list - keep the | |
1189 | * preferred driver at the head of the list. | |
1190 | */ | |
1191 | acquire_console_sem(); | |
1192 | if ((console->flags & CON_CONSDEV) || console_drivers == NULL) { | |
1193 | console->next = console_drivers; | |
1194 | console_drivers = console; | |
ab4af03a GE |
1195 | if (console->next) |
1196 | console->next->flags &= ~CON_CONSDEV; | |
1da177e4 LT |
1197 | } else { |
1198 | console->next = console_drivers->next; | |
1199 | console_drivers->next = console; | |
1200 | } | |
1201 | if (console->flags & CON_PRINTBUFFER) { | |
1202 | /* | |
1203 | * release_console_sem() will print out the buffered messages | |
1204 | * for us. | |
1205 | */ | |
1206 | spin_lock_irqsave(&logbuf_lock, flags); | |
1207 | con_start = log_start; | |
1208 | spin_unlock_irqrestore(&logbuf_lock, flags); | |
1209 | } | |
1210 | release_console_sem(); | |
1211 | } | |
1212 | EXPORT_SYMBOL(register_console); | |
1213 | ||
40dc5651 | 1214 | int unregister_console(struct console *console) |
1da177e4 | 1215 | { |
40dc5651 | 1216 | struct console *a, *b; |
1da177e4 LT |
1217 | int res = 1; |
1218 | ||
f7511d5f ST |
1219 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1220 | if (console->flags & CON_BRL) | |
1221 | return braille_unregister_console(console); | |
1222 | #endif | |
1223 | ||
1da177e4 LT |
1224 | acquire_console_sem(); |
1225 | if (console_drivers == console) { | |
1226 | console_drivers=console->next; | |
1227 | res = 0; | |
e9b15b54 | 1228 | } else if (console_drivers) { |
1da177e4 LT |
1229 | for (a=console_drivers->next, b=console_drivers ; |
1230 | a; b=a, a=b->next) { | |
1231 | if (a == console) { | |
1232 | b->next = a->next; | |
1233 | res = 0; | |
1234 | break; | |
40dc5651 | 1235 | } |
1da177e4 LT |
1236 | } |
1237 | } | |
40dc5651 | 1238 | |
69331af7 | 1239 | /* |
ab4af03a GE |
1240 | * If this isn't the last console and it has CON_CONSDEV set, we |
1241 | * need to set it on the next preferred console. | |
1da177e4 | 1242 | */ |
69331af7 | 1243 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 1244 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 LT |
1245 | |
1246 | release_console_sem(); | |
1247 | return res; | |
1248 | } | |
1249 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 1250 | |
0c5564bd RG |
1251 | static int __init disable_boot_consoles(void) |
1252 | { | |
cb00e99c RG |
1253 | if (console_drivers != NULL) { |
1254 | if (console_drivers->flags & CON_BOOT) { | |
1255 | printk(KERN_INFO "turn off boot console %s%d\n", | |
1256 | console_drivers->name, console_drivers->index); | |
1257 | return unregister_console(console_drivers); | |
1258 | } | |
0c5564bd RG |
1259 | } |
1260 | return 0; | |
1261 | } | |
1262 | late_initcall(disable_boot_consoles); | |
1263 | ||
7ef3d2fd | 1264 | #if defined CONFIG_PRINTK |
717115e1 | 1265 | |
1da177e4 LT |
1266 | /* |
1267 | * printk rate limiting, lifted from the networking subsystem. | |
1268 | * | |
641de9d8 UKK |
1269 | * This enforces a rate limit: not more than 10 kernel messages |
1270 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 1271 | */ |
641de9d8 UKK |
1272 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
1273 | ||
1da177e4 LT |
1274 | int printk_ratelimit(void) |
1275 | { | |
717115e1 | 1276 | return __ratelimit(&printk_ratelimit_state); |
1da177e4 LT |
1277 | } |
1278 | EXPORT_SYMBOL(printk_ratelimit); | |
f46c4833 AM |
1279 | |
1280 | /** | |
1281 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
1282 | * @caller_jiffies: pointer to caller's state | |
1283 | * @interval_msecs: minimum interval between prints | |
1284 | * | |
1285 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
1286 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
1287 | * returned true. | |
1288 | */ | |
1289 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
1290 | unsigned int interval_msecs) | |
1291 | { | |
1292 | if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) { | |
1293 | *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs); | |
1294 | return true; | |
1295 | } | |
1296 | return false; | |
1297 | } | |
1298 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
7ef3d2fd | 1299 | #endif |