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Commit | Line | Data |
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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> | |
162a7e75 | 34 | #include <linux/memblock.h> |
1da177e4 | 35 | #include <linux/syscalls.h> |
04d491ab | 36 | #include <linux/kexec.h> |
d37d39ae | 37 | #include <linux/kdb.h> |
3fff4c42 | 38 | #include <linux/ratelimit.h> |
456b565c | 39 | #include <linux/kmsg_dump.h> |
00234592 | 40 | #include <linux/syslog.h> |
034260d6 KC |
41 | #include <linux/cpu.h> |
42 | #include <linux/notifier.h> | |
fb842b00 | 43 | #include <linux/rculist.h> |
1da177e4 LT |
44 | |
45 | #include <asm/uaccess.h> | |
46 | ||
95100358 JB |
47 | #define CREATE_TRACE_POINTS |
48 | #include <trace/events/printk.h> | |
49 | ||
076f9776 IM |
50 | /* |
51 | * Architectures can override it: | |
52 | */ | |
e17ba73b | 53 | void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) |
076f9776 IM |
54 | { |
55 | } | |
56 | ||
1da177e4 | 57 | /* printk's without a loglevel use this.. */ |
5af5bcb8 | 58 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
1da177e4 LT |
59 | |
60 | /* We show everything that is MORE important than this.. */ | |
61 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ | |
62 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ | |
63 | ||
64 | DECLARE_WAIT_QUEUE_HEAD(log_wait); | |
65 | ||
66 | int console_printk[4] = { | |
67 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ | |
68 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ | |
69 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ | |
70 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ | |
71 | }; | |
72 | ||
1da177e4 | 73 | /* |
0bbfb7c2 | 74 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
75 | * their unblank() callback or not. So let's export it. |
76 | */ | |
77 | int oops_in_progress; | |
78 | EXPORT_SYMBOL(oops_in_progress); | |
79 | ||
80 | /* | |
81 | * console_sem protects the console_drivers list, and also | |
82 | * provides serialisation for access to the entire console | |
83 | * driver system. | |
84 | */ | |
5b8c4f23 | 85 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 86 | struct console *console_drivers; |
a29d1cfe IM |
87 | EXPORT_SYMBOL_GPL(console_drivers); |
88 | ||
1da177e4 LT |
89 | /* |
90 | * This is used for debugging the mess that is the VT code by | |
91 | * keeping track if we have the console semaphore held. It's | |
92 | * definitely not the perfect debug tool (we don't know if _WE_ | |
93 | * hold it are racing, but it helps tracking those weird code | |
94 | * path in the console code where we end up in places I want | |
95 | * locked without the console sempahore held | |
96 | */ | |
557240b4 | 97 | static int console_locked, console_suspended; |
1da177e4 | 98 | |
fe3d8ad3 FT |
99 | /* |
100 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
101 | */ | |
102 | static struct console *exclusive_console; | |
103 | ||
1da177e4 LT |
104 | /* |
105 | * Array of consoles built from command line options (console=) | |
106 | */ | |
107 | struct console_cmdline | |
108 | { | |
109 | char name[8]; /* Name of the driver */ | |
110 | int index; /* Minor dev. to use */ | |
111 | char *options; /* Options for the driver */ | |
f7511d5f ST |
112 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
113 | char *brl_options; /* Options for braille driver */ | |
114 | #endif | |
1da177e4 LT |
115 | }; |
116 | ||
117 | #define MAX_CMDLINECONSOLES 8 | |
118 | ||
119 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
120 | static int selected_console = -1; | |
121 | static int preferred_console = -1; | |
9e124fe1 MA |
122 | int console_set_on_cmdline; |
123 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
124 | |
125 | /* Flag: console code may call schedule() */ | |
126 | static int console_may_schedule; | |
127 | ||
d59745ce | 128 | #ifdef CONFIG_PRINTK |
7ff9554b KS |
129 | /* |
130 | * The printk log buffer consists of a chain of concatenated variable | |
131 | * length records. Every record starts with a record header, containing | |
132 | * the overall length of the record. | |
133 | * | |
134 | * The heads to the first and last entry in the buffer, as well as the | |
135 | * sequence numbers of these both entries are maintained when messages | |
136 | * are stored.. | |
137 | * | |
138 | * If the heads indicate available messages, the length in the header | |
139 | * tells the start next message. A length == 0 for the next message | |
140 | * indicates a wrap-around to the beginning of the buffer. | |
141 | * | |
142 | * Every record carries the monotonic timestamp in microseconds, as well as | |
143 | * the standard userspace syslog level and syslog facility. The usual | |
144 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
145 | * a matching syslog facility, by default LOG_USER. The origin of every | |
146 | * message can be reliably determined that way. | |
147 | * | |
148 | * The human readable log message directly follows the message header. The | |
149 | * length of the message text is stored in the header, the stored message | |
150 | * is not terminated. | |
151 | * | |
152 | */ | |
153 | ||
154 | struct log { | |
155 | u64 ts_nsec; /* timestamp in nanoseconds */ | |
156 | u16 len; /* length of entire record */ | |
157 | u16 text_len; /* length of text buffer */ | |
158 | u16 dict_len; /* length of dictionary buffer */ | |
159 | u16 level; /* syslog level + facility */ | |
160 | }; | |
161 | ||
162 | /* | |
163 | * The logbuf_lock protects kmsg buffer, indices, counters. It is also | |
164 | * used in interesting ways to provide interlocking in console_unlock(); | |
165 | */ | |
166 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 167 | |
7ff9554b KS |
168 | /* cpu currently holding logbuf_lock */ |
169 | static volatile unsigned int logbuf_cpu = UINT_MAX; | |
170 | ||
171 | #define LOG_LINE_MAX 1024 | |
172 | ||
173 | /* record buffer */ | |
174 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) | |
d59745ce MM |
175 | static char __log_buf[__LOG_BUF_LEN]; |
176 | static char *log_buf = __log_buf; | |
7ff9554b KS |
177 | static u32 log_buf_len = __LOG_BUF_LEN; |
178 | ||
179 | /* index and sequence number of the first record stored in the buffer */ | |
180 | static u64 log_first_seq; | |
181 | static u32 log_first_idx; | |
182 | ||
183 | /* index and sequence number of the next record to store in the buffer */ | |
184 | static u64 log_next_seq; | |
185 | static u32 log_next_idx; | |
186 | ||
187 | /* the next printk record to read after the last 'clear' command */ | |
188 | static u64 clear_seq; | |
189 | static u32 clear_idx; | |
190 | ||
191 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ | |
192 | static u64 syslog_seq; | |
193 | static u32 syslog_idx; | |
194 | ||
195 | /* human readable text of the record */ | |
196 | static char *log_text(const struct log *msg) | |
197 | { | |
198 | return (char *)msg + sizeof(struct log); | |
199 | } | |
200 | ||
201 | /* optional key/value pair dictionary attached to the record */ | |
202 | static char *log_dict(const struct log *msg) | |
203 | { | |
204 | return (char *)msg + sizeof(struct log) + msg->text_len; | |
205 | } | |
206 | ||
207 | /* get record by index; idx must point to valid msg */ | |
208 | static struct log *log_from_idx(u32 idx) | |
209 | { | |
210 | struct log *msg = (struct log *)(log_buf + idx); | |
211 | ||
212 | /* | |
213 | * A length == 0 record is the end of buffer marker. Wrap around and | |
214 | * read the message at the start of the buffer. | |
215 | */ | |
216 | if (!msg->len) | |
217 | return (struct log *)log_buf; | |
218 | return msg; | |
219 | } | |
220 | ||
221 | /* get next record; idx must point to valid msg */ | |
222 | static u32 log_next(u32 idx) | |
223 | { | |
224 | struct log *msg = (struct log *)(log_buf + idx); | |
225 | ||
226 | /* length == 0 indicates the end of the buffer; wrap */ | |
227 | /* | |
228 | * A length == 0 record is the end of buffer marker. Wrap around and | |
229 | * read the message at the start of the buffer as *this* one, and | |
230 | * return the one after that. | |
231 | */ | |
232 | if (!msg->len) { | |
233 | msg = (struct log *)log_buf; | |
234 | return msg->len; | |
235 | } | |
236 | return idx + msg->len; | |
237 | } | |
238 | ||
239 | #if !defined(CONFIG_64BIT) || defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) | |
240 | #define LOG_ALIGN 4 | |
241 | #else | |
242 | #define LOG_ALIGN 8 | |
243 | #endif | |
244 | ||
245 | /* insert record into the buffer, discard old ones, update heads */ | |
246 | static void log_store(int facility, int level, | |
247 | const char *dict, u16 dict_len, | |
248 | const char *text, u16 text_len) | |
249 | { | |
250 | struct log *msg; | |
251 | u32 size, pad_len; | |
252 | ||
253 | /* number of '\0' padding bytes to next message */ | |
254 | size = sizeof(struct log) + text_len + dict_len; | |
255 | pad_len = (-size) & (LOG_ALIGN - 1); | |
256 | size += pad_len; | |
257 | ||
258 | while (log_first_seq < log_next_seq) { | |
259 | u32 free; | |
260 | ||
261 | if (log_next_idx > log_first_idx) | |
262 | free = max(log_buf_len - log_next_idx, log_first_idx); | |
263 | else | |
264 | free = log_first_idx - log_next_idx; | |
265 | ||
266 | if (free > size + sizeof(struct log)) | |
267 | break; | |
268 | ||
269 | /* drop old messages until we have enough contiuous space */ | |
270 | log_first_idx = log_next(log_first_idx); | |
271 | log_first_seq++; | |
272 | } | |
273 | ||
274 | if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { | |
275 | /* | |
276 | * This message + an additional empty header does not fit | |
277 | * at the end of the buffer. Add an empty header with len == 0 | |
278 | * to signify a wrap around. | |
279 | */ | |
280 | memset(log_buf + log_next_idx, 0, sizeof(struct log)); | |
281 | log_next_idx = 0; | |
282 | } | |
283 | ||
284 | /* fill message */ | |
285 | msg = (struct log *)(log_buf + log_next_idx); | |
286 | memcpy(log_text(msg), text, text_len); | |
287 | msg->text_len = text_len; | |
288 | memcpy(log_dict(msg), dict, dict_len); | |
289 | msg->dict_len = dict_len; | |
290 | msg->level = (facility << 3) | (level & 7); | |
291 | msg->ts_nsec = local_clock(); | |
292 | memset(log_dict(msg) + dict_len, 0, pad_len); | |
293 | msg->len = sizeof(struct log) + text_len + dict_len + pad_len; | |
294 | ||
295 | /* insert message */ | |
296 | log_next_idx += msg->len; | |
297 | log_next_seq++; | |
298 | } | |
d59745ce | 299 | |
04d491ab NH |
300 | #ifdef CONFIG_KEXEC |
301 | /* | |
302 | * This appends the listed symbols to /proc/vmcoreinfo | |
303 | * | |
304 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to | |
305 | * obtain access to symbols that are otherwise very difficult to locate. These | |
306 | * symbols are specifically used so that utilities can access and extract the | |
307 | * dmesg log from a vmcore file after a crash. | |
308 | */ | |
309 | void log_buf_kexec_setup(void) | |
310 | { | |
311 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 312 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
313 | VMCOREINFO_SYMBOL(log_first_idx); |
314 | VMCOREINFO_SYMBOL(log_next_idx); | |
04d491ab NH |
315 | } |
316 | #endif | |
317 | ||
162a7e75 MT |
318 | /* requested log_buf_len from kernel cmdline */ |
319 | static unsigned long __initdata new_log_buf_len; | |
320 | ||
321 | /* save requested log_buf_len since it's too early to process it */ | |
1da177e4 LT |
322 | static int __init log_buf_len_setup(char *str) |
323 | { | |
eed4a2ab | 324 | unsigned size = memparse(str, &str); |
1da177e4 LT |
325 | |
326 | if (size) | |
327 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
328 | if (size > log_buf_len) |
329 | new_log_buf_len = size; | |
330 | ||
331 | return 0; | |
1da177e4 | 332 | } |
162a7e75 MT |
333 | early_param("log_buf_len", log_buf_len_setup); |
334 | ||
335 | void __init setup_log_buf(int early) | |
336 | { | |
337 | unsigned long flags; | |
162a7e75 MT |
338 | char *new_log_buf; |
339 | int free; | |
340 | ||
341 | if (!new_log_buf_len) | |
342 | return; | |
1da177e4 | 343 | |
162a7e75 MT |
344 | if (early) { |
345 | unsigned long mem; | |
346 | ||
347 | mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); | |
1f5026a7 | 348 | if (!mem) |
162a7e75 MT |
349 | return; |
350 | new_log_buf = __va(mem); | |
351 | } else { | |
352 | new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); | |
353 | } | |
354 | ||
355 | if (unlikely(!new_log_buf)) { | |
356 | pr_err("log_buf_len: %ld bytes not available\n", | |
357 | new_log_buf_len); | |
358 | return; | |
359 | } | |
360 | ||
07354eb1 | 361 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
362 | log_buf_len = new_log_buf_len; |
363 | log_buf = new_log_buf; | |
364 | new_log_buf_len = 0; | |
7ff9554b KS |
365 | free = __LOG_BUF_LEN - log_next_idx; |
366 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 367 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 MT |
368 | |
369 | pr_info("log_buf_len: %d\n", log_buf_len); | |
370 | pr_info("early log buf free: %d(%d%%)\n", | |
371 | free, (free * 100) / __LOG_BUF_LEN); | |
372 | } | |
1da177e4 | 373 | |
bfe8df3d RD |
374 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
375 | ||
674dff65 | 376 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 377 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
378 | |
379 | static int __init boot_delay_setup(char *str) | |
380 | { | |
381 | unsigned long lpj; | |
bfe8df3d RD |
382 | |
383 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
384 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
385 | ||
386 | get_option(&str, &boot_delay); | |
387 | if (boot_delay > 10 * 1000) | |
388 | boot_delay = 0; | |
389 | ||
3a3b6ed2 DY |
390 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
391 | "HZ: %d, loops_per_msec: %llu\n", | |
392 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
bfe8df3d RD |
393 | return 1; |
394 | } | |
395 | __setup("boot_delay=", boot_delay_setup); | |
396 | ||
397 | static void boot_delay_msec(void) | |
398 | { | |
399 | unsigned long long k; | |
400 | unsigned long timeout; | |
401 | ||
402 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) | |
403 | return; | |
404 | ||
3a3b6ed2 | 405 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
406 | |
407 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
408 | while (k) { | |
409 | k--; | |
410 | cpu_relax(); | |
411 | /* | |
412 | * use (volatile) jiffies to prevent | |
413 | * compiler reduction; loop termination via jiffies | |
414 | * is secondary and may or may not happen. | |
415 | */ | |
416 | if (time_after(jiffies, timeout)) | |
417 | break; | |
418 | touch_nmi_watchdog(); | |
419 | } | |
420 | } | |
421 | #else | |
422 | static inline void boot_delay_msec(void) | |
423 | { | |
424 | } | |
425 | #endif | |
426 | ||
eaf06b24 DR |
427 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
428 | int dmesg_restrict = 1; | |
429 | #else | |
430 | int dmesg_restrict; | |
431 | #endif | |
432 | ||
ee24aebf LT |
433 | static int syslog_action_restricted(int type) |
434 | { | |
435 | if (dmesg_restrict) | |
436 | return 1; | |
437 | /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ | |
438 | return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; | |
439 | } | |
440 | ||
441 | static int check_syslog_permissions(int type, bool from_file) | |
442 | { | |
443 | /* | |
444 | * If this is from /proc/kmsg and we've already opened it, then we've | |
445 | * already done the capabilities checks at open time. | |
446 | */ | |
447 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
448 | return 0; | |
449 | ||
450 | if (syslog_action_restricted(type)) { | |
451 | if (capable(CAP_SYSLOG)) | |
452 | return 0; | |
453 | /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ | |
454 | if (capable(CAP_SYS_ADMIN)) { | |
f2c0d026 JN |
455 | printk_once(KERN_WARNING "%s (%d): " |
456 | "Attempt to access syslog with CAP_SYS_ADMIN " | |
457 | "but no CAP_SYSLOG (deprecated).\n", | |
458 | current->comm, task_pid_nr(current)); | |
ee24aebf LT |
459 | return 0; |
460 | } | |
461 | return -EPERM; | |
462 | } | |
463 | return 0; | |
464 | } | |
465 | ||
7ff9554b KS |
466 | #if defined(CONFIG_PRINTK_TIME) |
467 | static bool printk_time = 1; | |
468 | #else | |
469 | static bool printk_time; | |
470 | #endif | |
471 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); | |
472 | ||
473 | static int syslog_print_line(u32 idx, char *text, size_t size) | |
474 | { | |
475 | struct log *msg; | |
476 | size_t len; | |
477 | ||
478 | msg = log_from_idx(idx); | |
479 | if (!text) { | |
480 | /* calculate length only */ | |
481 | len = 3; | |
482 | ||
483 | if (msg->level > 9) | |
484 | len++; | |
485 | if (msg->level > 99) | |
486 | len++; | |
487 | ||
488 | if (printk_time) | |
489 | len += 15; | |
490 | ||
491 | len += msg->text_len; | |
492 | len++; | |
493 | return len; | |
494 | } | |
495 | ||
496 | len = sprintf(text, "<%u>", msg->level); | |
497 | ||
498 | if (printk_time) { | |
499 | unsigned long long t = msg->ts_nsec; | |
500 | unsigned long rem_ns = do_div(t, 1000000000); | |
501 | ||
502 | len += sprintf(text + len, "[%5lu.%06lu] ", | |
503 | (unsigned long) t, rem_ns / 1000); | |
504 | } | |
505 | ||
506 | if (len + msg->text_len > size) | |
507 | return -EINVAL; | |
508 | memcpy(text + len, log_text(msg), msg->text_len); | |
509 | len += msg->text_len; | |
510 | text[len++] = '\n'; | |
511 | return len; | |
512 | } | |
513 | ||
514 | static int syslog_print(char __user *buf, int size) | |
515 | { | |
516 | char *text; | |
517 | int len; | |
518 | ||
519 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); | |
520 | if (!text) | |
521 | return -ENOMEM; | |
522 | ||
523 | raw_spin_lock_irq(&logbuf_lock); | |
524 | if (syslog_seq < log_first_seq) { | |
525 | /* messages are gone, move to first one */ | |
526 | syslog_seq = log_first_seq; | |
527 | syslog_idx = log_first_idx; | |
528 | } | |
529 | len = syslog_print_line(syslog_idx, text, LOG_LINE_MAX); | |
530 | syslog_idx = log_next(syslog_idx); | |
531 | syslog_seq++; | |
532 | raw_spin_unlock_irq(&logbuf_lock); | |
533 | ||
534 | if (len > 0 && copy_to_user(buf, text, len)) | |
535 | len = -EFAULT; | |
536 | ||
537 | kfree(text); | |
538 | return len; | |
539 | } | |
540 | ||
541 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
542 | { | |
543 | char *text; | |
544 | int len = 0; | |
545 | ||
546 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); | |
547 | if (!text) | |
548 | return -ENOMEM; | |
549 | ||
550 | raw_spin_lock_irq(&logbuf_lock); | |
551 | if (buf) { | |
552 | u64 next_seq; | |
553 | u64 seq; | |
554 | u32 idx; | |
555 | ||
556 | if (clear_seq < log_first_seq) { | |
557 | /* messages are gone, move to first available one */ | |
558 | clear_seq = log_first_seq; | |
559 | clear_idx = log_first_idx; | |
560 | } | |
561 | ||
562 | /* | |
563 | * Find first record that fits, including all following records, | |
564 | * into the user-provided buffer for this dump. | |
565 | */ | |
566 | seq = clear_seq; | |
567 | idx = clear_idx; | |
568 | while (seq < log_next_seq) { | |
569 | len += syslog_print_line(idx, NULL, 0); | |
570 | idx = log_next(idx); | |
571 | seq++; | |
572 | } | |
573 | seq = clear_seq; | |
574 | idx = clear_idx; | |
575 | while (len > size && seq < log_next_seq) { | |
576 | len -= syslog_print_line(idx, NULL, 0); | |
577 | idx = log_next(idx); | |
578 | seq++; | |
579 | } | |
580 | ||
581 | /* last message in this dump */ | |
582 | next_seq = log_next_seq; | |
583 | ||
584 | len = 0; | |
585 | while (len >= 0 && seq < next_seq) { | |
586 | int textlen; | |
587 | ||
588 | textlen = syslog_print_line(idx, text, LOG_LINE_MAX); | |
589 | if (textlen < 0) { | |
590 | len = textlen; | |
591 | break; | |
592 | } | |
593 | idx = log_next(idx); | |
594 | seq++; | |
595 | ||
596 | raw_spin_unlock_irq(&logbuf_lock); | |
597 | if (copy_to_user(buf + len, text, textlen)) | |
598 | len = -EFAULT; | |
599 | else | |
600 | len += textlen; | |
601 | raw_spin_lock_irq(&logbuf_lock); | |
602 | ||
603 | if (seq < log_first_seq) { | |
604 | /* messages are gone, move to next one */ | |
605 | seq = log_first_seq; | |
606 | idx = log_first_idx; | |
607 | } | |
608 | } | |
609 | } | |
610 | ||
611 | if (clear) { | |
612 | clear_seq = log_next_seq; | |
613 | clear_idx = log_next_idx; | |
614 | } | |
615 | raw_spin_unlock_irq(&logbuf_lock); | |
616 | ||
617 | kfree(text); | |
618 | return len; | |
619 | } | |
620 | ||
00234592 | 621 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 622 | { |
7ff9554b KS |
623 | bool clear = false; |
624 | static int saved_console_loglevel = -1; | |
ee24aebf | 625 | int error; |
1da177e4 | 626 | |
ee24aebf LT |
627 | error = check_syslog_permissions(type, from_file); |
628 | if (error) | |
629 | goto out; | |
12b3052c EP |
630 | |
631 | error = security_syslog(type); | |
1da177e4 LT |
632 | if (error) |
633 | return error; | |
634 | ||
635 | switch (type) { | |
d78ca3cd | 636 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 637 | break; |
d78ca3cd | 638 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 639 | break; |
d78ca3cd | 640 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
641 | error = -EINVAL; |
642 | if (!buf || len < 0) | |
643 | goto out; | |
644 | error = 0; | |
645 | if (!len) | |
646 | goto out; | |
647 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
648 | error = -EFAULT; | |
649 | goto out; | |
650 | } | |
40dc5651 | 651 | error = wait_event_interruptible(log_wait, |
7ff9554b | 652 | syslog_seq != log_next_seq); |
1da177e4 LT |
653 | if (error) |
654 | goto out; | |
7ff9554b | 655 | error = syslog_print(buf, len); |
1da177e4 | 656 | break; |
d78ca3cd KC |
657 | /* Read/clear last kernel messages */ |
658 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 659 | clear = true; |
1da177e4 | 660 | /* FALL THRU */ |
d78ca3cd KC |
661 | /* Read last kernel messages */ |
662 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
663 | error = -EINVAL; |
664 | if (!buf || len < 0) | |
665 | goto out; | |
666 | error = 0; | |
667 | if (!len) | |
668 | goto out; | |
669 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
670 | error = -EFAULT; | |
671 | goto out; | |
672 | } | |
7ff9554b | 673 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 674 | break; |
d78ca3cd KC |
675 | /* Clear ring buffer */ |
676 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 677 | syslog_print_all(NULL, 0, true); |
d78ca3cd KC |
678 | /* Disable logging to console */ |
679 | case SYSLOG_ACTION_CONSOLE_OFF: | |
1aaad49e FP |
680 | if (saved_console_loglevel == -1) |
681 | saved_console_loglevel = console_loglevel; | |
1da177e4 LT |
682 | console_loglevel = minimum_console_loglevel; |
683 | break; | |
d78ca3cd KC |
684 | /* Enable logging to console */ |
685 | case SYSLOG_ACTION_CONSOLE_ON: | |
1aaad49e FP |
686 | if (saved_console_loglevel != -1) { |
687 | console_loglevel = saved_console_loglevel; | |
688 | saved_console_loglevel = -1; | |
689 | } | |
1da177e4 | 690 | break; |
d78ca3cd KC |
691 | /* Set level of messages printed to console */ |
692 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
693 | error = -EINVAL; |
694 | if (len < 1 || len > 8) | |
695 | goto out; | |
696 | if (len < minimum_console_loglevel) | |
697 | len = minimum_console_loglevel; | |
698 | console_loglevel = len; | |
1aaad49e FP |
699 | /* Implicitly re-enable logging to console */ |
700 | saved_console_loglevel = -1; | |
1da177e4 LT |
701 | error = 0; |
702 | break; | |
d78ca3cd KC |
703 | /* Number of chars in the log buffer */ |
704 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
705 | raw_spin_lock_irq(&logbuf_lock); |
706 | if (syslog_seq < log_first_seq) { | |
707 | /* messages are gone, move to first one */ | |
708 | syslog_seq = log_first_seq; | |
709 | syslog_idx = log_first_idx; | |
710 | } | |
711 | if (from_file) { | |
712 | /* | |
713 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
714 | * for pending data, not the size; return the count of | |
715 | * records, not the length. | |
716 | */ | |
717 | error = log_next_idx - syslog_idx; | |
718 | } else { | |
719 | u64 seq; | |
720 | u32 idx; | |
721 | ||
722 | error = 0; | |
723 | seq = syslog_seq; | |
724 | idx = syslog_idx; | |
725 | while (seq < log_next_seq) { | |
726 | error += syslog_print_line(idx, NULL, 0); | |
727 | idx = log_next(idx); | |
728 | seq++; | |
729 | } | |
730 | } | |
731 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 732 | break; |
d78ca3cd KC |
733 | /* Size of the log buffer */ |
734 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
735 | error = log_buf_len; |
736 | break; | |
737 | default: | |
738 | error = -EINVAL; | |
739 | break; | |
740 | } | |
741 | out: | |
742 | return error; | |
743 | } | |
744 | ||
1e7bfb21 | 745 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 746 | { |
00234592 | 747 | return do_syslog(type, buf, len, SYSLOG_FROM_CALL); |
1da177e4 LT |
748 | } |
749 | ||
67fc4e0c JW |
750 | #ifdef CONFIG_KGDB_KDB |
751 | /* kdb dmesg command needs access to the syslog buffer. do_syslog() | |
752 | * uses locks so it cannot be used during debugging. Just tell kdb | |
753 | * where the start and end of the physical and logical logs are. This | |
754 | * is equivalent to do_syslog(3). | |
755 | */ | |
756 | void kdb_syslog_data(char *syslog_data[4]) | |
757 | { | |
758 | syslog_data[0] = log_buf; | |
759 | syslog_data[1] = log_buf + log_buf_len; | |
7ff9554b KS |
760 | syslog_data[2] = log_buf + log_first_idx; |
761 | syslog_data[3] = log_buf + log_next_idx; | |
67fc4e0c JW |
762 | } |
763 | #endif /* CONFIG_KGDB_KDB */ | |
764 | ||
2329abfa | 765 | static bool __read_mostly ignore_loglevel; |
79290822 | 766 | |
99eea6a1 | 767 | static int __init ignore_loglevel_setup(char *str) |
79290822 IM |
768 | { |
769 | ignore_loglevel = 1; | |
770 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); | |
771 | ||
c4772d99 | 772 | return 0; |
79290822 IM |
773 | } |
774 | ||
c4772d99 | 775 | early_param("ignore_loglevel", ignore_loglevel_setup); |
29d4d6df | 776 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); |
0eca6b7c YZ |
777 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" |
778 | "print all kernel messages to the console."); | |
79290822 | 779 | |
1da177e4 LT |
780 | /* |
781 | * Call the console drivers, asking them to write out | |
782 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 783 | * The console_lock must be held. |
1da177e4 | 784 | */ |
7ff9554b | 785 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 786 | { |
7ff9554b | 787 | struct console *con; |
1da177e4 | 788 | |
7ff9554b KS |
789 | trace_console(text, 0, len, len); |
790 | ||
791 | if (level >= console_loglevel && !ignore_loglevel) | |
792 | return; | |
793 | if (!console_drivers) | |
794 | return; | |
795 | ||
796 | for_each_console(con) { | |
797 | if (exclusive_console && con != exclusive_console) | |
798 | continue; | |
799 | if (!(con->flags & CON_ENABLED)) | |
800 | continue; | |
801 | if (!con->write) | |
802 | continue; | |
803 | if (!cpu_online(smp_processor_id()) && | |
804 | !(con->flags & CON_ANYTIME)) | |
805 | continue; | |
806 | con->write(con, text, len); | |
807 | } | |
1da177e4 LT |
808 | } |
809 | ||
810 | /* | |
811 | * Zap console related locks when oopsing. Only zap at most once | |
812 | * every 10 seconds, to leave time for slow consoles to print a | |
813 | * full oops. | |
814 | */ | |
815 | static void zap_locks(void) | |
816 | { | |
817 | static unsigned long oops_timestamp; | |
818 | ||
819 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 820 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
821 | return; |
822 | ||
823 | oops_timestamp = jiffies; | |
824 | ||
94d24fc4 | 825 | debug_locks_off(); |
1da177e4 | 826 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 827 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 828 | /* And make sure that we print immediately */ |
5b8c4f23 | 829 | sema_init(&console_sem, 1); |
1da177e4 LT |
830 | } |
831 | ||
76a8ad29 ME |
832 | /* Check if we have any console registered that can be called early in boot. */ |
833 | static int have_callable_console(void) | |
834 | { | |
835 | struct console *con; | |
836 | ||
4d091611 | 837 | for_each_console(con) |
76a8ad29 ME |
838 | if (con->flags & CON_ANYTIME) |
839 | return 1; | |
840 | ||
841 | return 0; | |
842 | } | |
843 | ||
266c2e0a LT |
844 | /* |
845 | * Can we actually use the console at this time on this cpu? | |
846 | * | |
847 | * Console drivers may assume that per-cpu resources have | |
848 | * been allocated. So unless they're explicitly marked as | |
849 | * being able to cope (CON_ANYTIME) don't call them until | |
850 | * this CPU is officially up. | |
851 | */ | |
852 | static inline int can_use_console(unsigned int cpu) | |
853 | { | |
854 | return cpu_online(cpu) || have_callable_console(); | |
855 | } | |
856 | ||
857 | /* | |
858 | * Try to get console ownership to actually show the kernel | |
859 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 860 | * console_lock held, and 'console_locked' set) if it |
266c2e0a LT |
861 | * is successful, false otherwise. |
862 | * | |
863 | * This gets called with the 'logbuf_lock' spinlock held and | |
864 | * interrupts disabled. It should return with 'lockbuf_lock' | |
865 | * released but interrupts still disabled. | |
866 | */ | |
ac751efa | 867 | static int console_trylock_for_printk(unsigned int cpu) |
8155c02a | 868 | __releases(&logbuf_lock) |
266c2e0a | 869 | { |
0b5e1c52 | 870 | int retval = 0, wake = 0; |
266c2e0a | 871 | |
ac751efa | 872 | if (console_trylock()) { |
093a07e2 LT |
873 | retval = 1; |
874 | ||
875 | /* | |
876 | * If we can't use the console, we need to release | |
877 | * the console semaphore by hand to avoid flushing | |
878 | * the buffer. We need to hold the console semaphore | |
879 | * in order to do this test safely. | |
880 | */ | |
881 | if (!can_use_console(cpu)) { | |
882 | console_locked = 0; | |
0b5e1c52 | 883 | wake = 1; |
093a07e2 LT |
884 | retval = 0; |
885 | } | |
886 | } | |
7ff9554b | 887 | logbuf_cpu = UINT_MAX; |
0b5e1c52 PZ |
888 | if (wake) |
889 | up(&console_sem); | |
07354eb1 | 890 | raw_spin_unlock(&logbuf_lock); |
266c2e0a LT |
891 | return retval; |
892 | } | |
32a76006 | 893 | |
af91322e DY |
894 | int printk_delay_msec __read_mostly; |
895 | ||
896 | static inline void printk_delay(void) | |
897 | { | |
898 | if (unlikely(printk_delay_msec)) { | |
899 | int m = printk_delay_msec; | |
900 | ||
901 | while (m--) { | |
902 | mdelay(1); | |
903 | touch_nmi_watchdog(); | |
904 | } | |
905 | } | |
906 | } | |
907 | ||
7ff9554b KS |
908 | asmlinkage int vprintk_emit(int facility, int level, |
909 | const char *dict, size_t dictlen, | |
910 | const char *fmt, va_list args) | |
1da177e4 | 911 | { |
7ff9554b KS |
912 | static int recursion_bug; |
913 | static char buf[LOG_LINE_MAX]; | |
914 | static size_t buflen; | |
915 | static int buflevel; | |
916 | static char textbuf[LOG_LINE_MAX]; | |
917 | char *text = textbuf; | |
918 | size_t textlen; | |
ac60ad74 | 919 | unsigned long flags; |
32a76006 | 920 | int this_cpu; |
7ff9554b KS |
921 | bool newline = false; |
922 | bool cont = false; | |
923 | int printed_len = 0; | |
1da177e4 | 924 | |
bfe8df3d | 925 | boot_delay_msec(); |
af91322e | 926 | printk_delay(); |
bfe8df3d | 927 | |
1da177e4 | 928 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 929 | local_irq_save(flags); |
32a76006 IM |
930 | this_cpu = smp_processor_id(); |
931 | ||
932 | /* | |
933 | * Ouch, printk recursed into itself! | |
934 | */ | |
7ff9554b | 935 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
936 | /* |
937 | * If a crash is occurring during printk() on this CPU, | |
938 | * then try to get the crash message out but make sure | |
939 | * we can't deadlock. Otherwise just return to avoid the | |
940 | * recursion and return - but flag the recursion so that | |
941 | * it can be printed at the next appropriate moment: | |
942 | */ | |
94d24fc4 | 943 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 944 | recursion_bug = 1; |
32a76006 IM |
945 | goto out_restore_irqs; |
946 | } | |
947 | zap_locks(); | |
948 | } | |
949 | ||
a0f1ccfd | 950 | lockdep_off(); |
07354eb1 | 951 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 952 | logbuf_cpu = this_cpu; |
1da177e4 | 953 | |
3b8945e8 | 954 | if (recursion_bug) { |
7ff9554b KS |
955 | static const char recursion_msg[] = |
956 | "BUG: recent printk recursion!"; | |
957 | ||
3b8945e8 | 958 | recursion_bug = 0; |
7ff9554b KS |
959 | printed_len += strlen(recursion_msg); |
960 | /* emit KERN_CRIT message */ | |
961 | log_store(0, 2, NULL, 0, recursion_msg, printed_len); | |
32a76006 | 962 | } |
1da177e4 | 963 | |
7ff9554b KS |
964 | /* |
965 | * The printf needs to come first; we need the syslog | |
966 | * prefix which might be passed-in as a parameter. | |
967 | */ | |
968 | textlen = vscnprintf(text, sizeof(textbuf), fmt, args); | |
5fd29d6c | 969 | |
7ff9554b KS |
970 | /* mark and strip a trailing newline */ |
971 | if (textlen && text[textlen-1] == '\n') { | |
972 | textlen--; | |
973 | newline = true; | |
974 | } | |
9d90c8d9 | 975 | |
7ff9554b KS |
976 | /* strip syslog prefix and extract log level or flags */ |
977 | if (text[0] == '<' && text[1] && text[2] == '>') { | |
978 | switch (text[1]) { | |
979 | case '0' ... '7': | |
980 | if (level == -1) | |
981 | level = text[1] - '0'; | |
982 | text += 3; | |
983 | textlen -= 3; | |
984 | break; | |
985 | case 'c': /* KERN_CONT */ | |
986 | cont = true; | |
987 | case 'd': /* KERN_DEFAULT */ | |
988 | text += 3; | |
989 | textlen -= 3; | |
9d90c8d9 | 990 | break; |
5fd29d6c LT |
991 | } |
992 | } | |
993 | ||
7ff9554b KS |
994 | if (buflen && (!cont || dict)) { |
995 | /* no continuation; flush existing buffer */ | |
996 | log_store(facility, buflevel, NULL, 0, buf, buflen); | |
997 | printed_len += buflen; | |
998 | buflen = 0; | |
999 | } | |
9d90c8d9 | 1000 | |
7ff9554b KS |
1001 | if (buflen == 0) { |
1002 | /* remember level for first message in the buffer */ | |
1003 | if (level == -1) | |
1004 | buflevel = default_message_loglevel; | |
1005 | else | |
1006 | buflevel = level; | |
1007 | } | |
ac60ad74 | 1008 | |
7ff9554b KS |
1009 | if (buflen || !newline) { |
1010 | /* append to existing buffer, or buffer until next message */ | |
1011 | if (buflen + textlen > sizeof(buf)) | |
1012 | textlen = sizeof(buf) - buflen; | |
1013 | memcpy(buf + buflen, text, textlen); | |
1014 | buflen += textlen; | |
1015 | } | |
ac60ad74 | 1016 | |
7ff9554b KS |
1017 | if (newline) { |
1018 | /* end of line; flush buffer */ | |
1019 | if (buflen) { | |
1020 | log_store(facility, buflevel, | |
1021 | dict, dictlen, buf, buflen); | |
1022 | printed_len += buflen; | |
1023 | buflen = 0; | |
1024 | } else { | |
1025 | log_store(facility, buflevel, | |
1026 | dict, dictlen, text, textlen); | |
1027 | printed_len += textlen; | |
1028 | } | |
1da177e4 LT |
1029 | } |
1030 | ||
266c2e0a | 1031 | /* |
7ff9554b KS |
1032 | * Try to acquire and then immediately release the console semaphore. |
1033 | * The release will print out buffers and wake up /dev/kmsg and syslog() | |
1034 | * users. | |
266c2e0a | 1035 | * |
7ff9554b KS |
1036 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
1037 | * regardless of whether it actually gets the console semaphore or not. | |
266c2e0a | 1038 | */ |
ac751efa TH |
1039 | if (console_trylock_for_printk(this_cpu)) |
1040 | console_unlock(); | |
76a8ad29 | 1041 | |
266c2e0a | 1042 | lockdep_on(); |
32a76006 | 1043 | out_restore_irqs: |
1a9a8aef | 1044 | local_irq_restore(flags); |
76a8ad29 | 1045 | |
1da177e4 LT |
1046 | return printed_len; |
1047 | } | |
7ff9554b KS |
1048 | EXPORT_SYMBOL(vprintk_emit); |
1049 | ||
1050 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1051 | { | |
1052 | return vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1053 | } | |
1da177e4 LT |
1054 | EXPORT_SYMBOL(vprintk); |
1055 | ||
7ff9554b KS |
1056 | asmlinkage int printk_emit(int facility, int level, |
1057 | const char *dict, size_t dictlen, | |
1058 | const char *fmt, ...) | |
1059 | { | |
1060 | va_list args; | |
1061 | int r; | |
1062 | ||
1063 | va_start(args, fmt); | |
1064 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1065 | va_end(args); | |
1066 | ||
1067 | return r; | |
1068 | } | |
1069 | EXPORT_SYMBOL(printk_emit); | |
1070 | ||
1071 | /** | |
1072 | * printk - print a kernel message | |
1073 | * @fmt: format string | |
1074 | * | |
1075 | * This is printk(). It can be called from any context. We want it to work. | |
1076 | * | |
1077 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1078 | * output and call the console drivers. If we fail to get the semaphore, we | |
1079 | * place the output into the log buffer and return. The current holder of | |
1080 | * the console_sem will notice the new output in console_unlock(); and will | |
1081 | * send it to the consoles before releasing the lock. | |
1082 | * | |
1083 | * One effect of this deferred printing is that code which calls printk() and | |
1084 | * then changes console_loglevel may break. This is because console_loglevel | |
1085 | * is inspected when the actual printing occurs. | |
1086 | * | |
1087 | * See also: | |
1088 | * printf(3) | |
1089 | * | |
1090 | * See the vsnprintf() documentation for format string extensions over C99. | |
1091 | */ | |
1092 | asmlinkage int printk(const char *fmt, ...) | |
1093 | { | |
1094 | va_list args; | |
1095 | int r; | |
1096 | ||
1097 | #ifdef CONFIG_KGDB_KDB | |
1098 | if (unlikely(kdb_trap_printk)) { | |
1099 | va_start(args, fmt); | |
1100 | r = vkdb_printf(fmt, args); | |
1101 | va_end(args); | |
1102 | return r; | |
1103 | } | |
1104 | #endif | |
1105 | va_start(args, fmt); | |
1106 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1107 | va_end(args); | |
1108 | ||
1109 | return r; | |
1110 | } | |
1111 | EXPORT_SYMBOL(printk); | |
d59745ce MM |
1112 | #else |
1113 | ||
7ff9554b | 1114 | static void call_console_drivers(int level, const char *text, size_t len) |
40dc5651 JJ |
1115 | { |
1116 | } | |
d59745ce MM |
1117 | |
1118 | #endif | |
1119 | ||
f7511d5f ST |
1120 | static int __add_preferred_console(char *name, int idx, char *options, |
1121 | char *brl_options) | |
1122 | { | |
1123 | struct console_cmdline *c; | |
1124 | int i; | |
1125 | ||
1126 | /* | |
1127 | * See if this tty is not yet registered, and | |
1128 | * if we have a slot free. | |
1129 | */ | |
1130 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1131 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1132 | console_cmdline[i].index == idx) { | |
1133 | if (!brl_options) | |
1134 | selected_console = i; | |
1135 | return 0; | |
1136 | } | |
1137 | if (i == MAX_CMDLINECONSOLES) | |
1138 | return -E2BIG; | |
1139 | if (!brl_options) | |
1140 | selected_console = i; | |
1141 | c = &console_cmdline[i]; | |
1142 | strlcpy(c->name, name, sizeof(c->name)); | |
1143 | c->options = options; | |
1144 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE | |
1145 | c->brl_options = brl_options; | |
1146 | #endif | |
1147 | c->index = idx; | |
1148 | return 0; | |
1149 | } | |
2ea1c539 JB |
1150 | /* |
1151 | * Set up a list of consoles. Called from init/main.c | |
1152 | */ | |
1153 | static int __init console_setup(char *str) | |
1154 | { | |
eaa944af | 1155 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 1156 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1157 | int idx; |
1158 | ||
f7511d5f ST |
1159 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1160 | if (!memcmp(str, "brl,", 4)) { | |
1161 | brl_options = ""; | |
1162 | str += 4; | |
1163 | } else if (!memcmp(str, "brl=", 4)) { | |
1164 | brl_options = str + 4; | |
1165 | str = strchr(brl_options, ','); | |
1166 | if (!str) { | |
1167 | printk(KERN_ERR "need port name after brl=\n"); | |
1168 | return 1; | |
1169 | } | |
1170 | *(str++) = 0; | |
1171 | } | |
1172 | #endif | |
1173 | ||
2ea1c539 JB |
1174 | /* |
1175 | * Decode str into name, index, options. | |
1176 | */ | |
1177 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1178 | strcpy(buf, "ttyS"); |
1179 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1180 | } else { |
eaa944af | 1181 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1182 | } |
eaa944af | 1183 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
1184 | if ((options = strchr(str, ',')) != NULL) |
1185 | *(options++) = 0; | |
1186 | #ifdef __sparc__ | |
1187 | if (!strcmp(str, "ttya")) | |
eaa944af | 1188 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1189 | if (!strcmp(str, "ttyb")) |
eaa944af | 1190 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1191 | #endif |
eaa944af | 1192 | for (s = buf; *s; s++) |
2ea1c539 JB |
1193 | if ((*s >= '0' && *s <= '9') || *s == ',') |
1194 | break; | |
1195 | idx = simple_strtoul(s, NULL, 10); | |
1196 | *s = 0; | |
1197 | ||
f7511d5f | 1198 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1199 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1200 | return 1; |
1201 | } | |
1202 | __setup("console=", console_setup); | |
1203 | ||
3c0547ba MM |
1204 | /** |
1205 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1206 | * @name: device name |
1207 | * @idx: device index | |
1208 | * @options: options for this console | |
3c0547ba MM |
1209 | * |
1210 | * The last preferred console added will be used for kernel messages | |
1211 | * and stdin/out/err for init. Normally this is used by console_setup | |
1212 | * above to handle user-supplied console arguments; however it can also | |
1213 | * be used by arch-specific code either to override the user or more | |
1214 | * commonly to provide a default console (ie from PROM variables) when | |
1215 | * the user has not supplied one. | |
1216 | */ | |
fb445ee5 | 1217 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 1218 | { |
f7511d5f | 1219 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
1220 | } |
1221 | ||
b6b1d877 | 1222 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
1223 | { |
1224 | struct console_cmdline *c; | |
1225 | int i; | |
1226 | ||
1227 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1228 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1229 | console_cmdline[i].index == idx) { | |
1230 | c = &console_cmdline[i]; | |
f735295b | 1231 | strlcpy(c->name, name_new, sizeof(c->name)); |
18a8bd94 YL |
1232 | c->name[sizeof(c->name) - 1] = 0; |
1233 | c->options = options; | |
1234 | c->index = idx_new; | |
1235 | return i; | |
1236 | } | |
1237 | /* not found */ | |
1238 | return -1; | |
1239 | } | |
1240 | ||
2329abfa | 1241 | bool console_suspend_enabled = 1; |
8f4ce8c3 AS |
1242 | EXPORT_SYMBOL(console_suspend_enabled); |
1243 | ||
1244 | static int __init console_suspend_disable(char *str) | |
1245 | { | |
1246 | console_suspend_enabled = 0; | |
1247 | return 1; | |
1248 | } | |
1249 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
1250 | module_param_named(console_suspend, console_suspend_enabled, |
1251 | bool, S_IRUGO | S_IWUSR); | |
1252 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
1253 | " and hibernate operations"); | |
8f4ce8c3 | 1254 | |
557240b4 LT |
1255 | /** |
1256 | * suspend_console - suspend the console subsystem | |
1257 | * | |
1258 | * This disables printk() while we go into suspend states | |
1259 | */ | |
1260 | void suspend_console(void) | |
1261 | { | |
8f4ce8c3 AS |
1262 | if (!console_suspend_enabled) |
1263 | return; | |
0d63081d | 1264 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 1265 | console_lock(); |
557240b4 | 1266 | console_suspended = 1; |
403f3075 | 1267 | up(&console_sem); |
557240b4 LT |
1268 | } |
1269 | ||
1270 | void resume_console(void) | |
1271 | { | |
8f4ce8c3 AS |
1272 | if (!console_suspend_enabled) |
1273 | return; | |
403f3075 | 1274 | down(&console_sem); |
557240b4 | 1275 | console_suspended = 0; |
ac751efa | 1276 | console_unlock(); |
557240b4 LT |
1277 | } |
1278 | ||
034260d6 KC |
1279 | /** |
1280 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
1281 | * @self: notifier struct | |
1282 | * @action: CPU hotplug event | |
1283 | * @hcpu: unused | |
1284 | * | |
1285 | * If printk() is called from a CPU that is not online yet, the messages | |
1286 | * will be spooled but will not show up on the console. This function is | |
1287 | * called when a new CPU comes online (or fails to come up), and ensures | |
1288 | * that any such output gets printed. | |
1289 | */ | |
1290 | static int __cpuinit console_cpu_notify(struct notifier_block *self, | |
1291 | unsigned long action, void *hcpu) | |
1292 | { | |
1293 | switch (action) { | |
1294 | case CPU_ONLINE: | |
1295 | case CPU_DEAD: | |
1296 | case CPU_DYING: | |
1297 | case CPU_DOWN_FAILED: | |
1298 | case CPU_UP_CANCELED: | |
ac751efa TH |
1299 | console_lock(); |
1300 | console_unlock(); | |
034260d6 KC |
1301 | } |
1302 | return NOTIFY_OK; | |
1303 | } | |
1304 | ||
1da177e4 | 1305 | /** |
ac751efa | 1306 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 1307 | * |
ac751efa | 1308 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
1309 | * exclusive access to the console system and the console_drivers list. |
1310 | * | |
1311 | * Can sleep, returns nothing. | |
1312 | */ | |
ac751efa | 1313 | void console_lock(void) |
1da177e4 | 1314 | { |
8abd8e29 | 1315 | BUG_ON(in_interrupt()); |
1da177e4 | 1316 | down(&console_sem); |
403f3075 AH |
1317 | if (console_suspended) |
1318 | return; | |
1da177e4 LT |
1319 | console_locked = 1; |
1320 | console_may_schedule = 1; | |
1321 | } | |
ac751efa | 1322 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 1323 | |
ac751efa TH |
1324 | /** |
1325 | * console_trylock - try to lock the console system for exclusive use. | |
1326 | * | |
1327 | * Tried to acquire a lock which guarantees that the caller has | |
1328 | * exclusive access to the console system and the console_drivers list. | |
1329 | * | |
1330 | * returns 1 on success, and 0 on failure to acquire the lock. | |
1331 | */ | |
1332 | int console_trylock(void) | |
1da177e4 LT |
1333 | { |
1334 | if (down_trylock(&console_sem)) | |
ac751efa | 1335 | return 0; |
403f3075 AH |
1336 | if (console_suspended) { |
1337 | up(&console_sem); | |
ac751efa | 1338 | return 0; |
403f3075 | 1339 | } |
1da177e4 LT |
1340 | console_locked = 1; |
1341 | console_may_schedule = 0; | |
ac751efa | 1342 | return 1; |
1da177e4 | 1343 | } |
ac751efa | 1344 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
1345 | |
1346 | int is_console_locked(void) | |
1347 | { | |
1348 | return console_locked; | |
1349 | } | |
1da177e4 | 1350 | |
3ccf3e83 | 1351 | /* |
7ff9554b | 1352 | * Delayed printk version, for scheduler-internal messages: |
3ccf3e83 PZ |
1353 | */ |
1354 | #define PRINTK_BUF_SIZE 512 | |
1355 | ||
1356 | #define PRINTK_PENDING_WAKEUP 0x01 | |
1357 | #define PRINTK_PENDING_SCHED 0x02 | |
1358 | ||
b845b517 | 1359 | static DEFINE_PER_CPU(int, printk_pending); |
3ccf3e83 | 1360 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); |
b845b517 PZ |
1361 | |
1362 | void printk_tick(void) | |
e3e8a75d | 1363 | { |
40dc11ff | 1364 | if (__this_cpu_read(printk_pending)) { |
3ccf3e83 PZ |
1365 | int pending = __this_cpu_xchg(printk_pending, 0); |
1366 | if (pending & PRINTK_PENDING_SCHED) { | |
1367 | char *buf = __get_cpu_var(printk_sched_buf); | |
1368 | printk(KERN_WARNING "[sched_delayed] %s", buf); | |
1369 | } | |
1370 | if (pending & PRINTK_PENDING_WAKEUP) | |
1371 | wake_up_interruptible(&log_wait); | |
b845b517 PZ |
1372 | } |
1373 | } | |
1374 | ||
1375 | int printk_needs_cpu(int cpu) | |
1376 | { | |
40dc11ff | 1377 | if (cpu_is_offline(cpu)) |
61ab2544 | 1378 | printk_tick(); |
40dc11ff | 1379 | return __this_cpu_read(printk_pending); |
b845b517 PZ |
1380 | } |
1381 | ||
1382 | void wake_up_klogd(void) | |
1383 | { | |
1384 | if (waitqueue_active(&log_wait)) | |
3ccf3e83 | 1385 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); |
e3e8a75d KK |
1386 | } |
1387 | ||
7ff9554b KS |
1388 | /* the next printk record to write to the console */ |
1389 | static u64 console_seq; | |
1390 | static u32 console_idx; | |
1391 | ||
1da177e4 | 1392 | /** |
ac751efa | 1393 | * console_unlock - unlock the console system |
1da177e4 | 1394 | * |
ac751efa | 1395 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
1396 | * and the console driver list. |
1397 | * | |
ac751efa TH |
1398 | * While the console_lock was held, console output may have been buffered |
1399 | * by printk(). If this is the case, console_unlock(); emits | |
1400 | * the output prior to releasing the lock. | |
1da177e4 | 1401 | * |
7ff9554b | 1402 | * If there is output waiting, we wake it /dev/kmsg and syslog() users. |
1da177e4 | 1403 | * |
ac751efa | 1404 | * console_unlock(); may be called from any context. |
1da177e4 | 1405 | */ |
ac751efa | 1406 | void console_unlock(void) |
1da177e4 | 1407 | { |
7ff9554b | 1408 | static u64 seen_seq; |
1da177e4 | 1409 | unsigned long flags; |
7ff9554b KS |
1410 | bool wake_klogd = false; |
1411 | bool retry; | |
1da177e4 | 1412 | |
557240b4 | 1413 | if (console_suspended) { |
403f3075 | 1414 | up(&console_sem); |
557240b4 LT |
1415 | return; |
1416 | } | |
78944e54 AD |
1417 | |
1418 | console_may_schedule = 0; | |
1419 | ||
4f2a8d3c | 1420 | again: |
7ff9554b KS |
1421 | for (;;) { |
1422 | struct log *msg; | |
1423 | static char text[LOG_LINE_MAX]; | |
1424 | size_t len; | |
1425 | int level; | |
1426 | ||
07354eb1 | 1427 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
1428 | if (seen_seq != log_next_seq) { |
1429 | wake_klogd = true; | |
1430 | seen_seq = log_next_seq; | |
1431 | } | |
1432 | ||
1433 | if (console_seq < log_first_seq) { | |
1434 | /* messages are gone, move to first one */ | |
1435 | console_seq = log_first_seq; | |
1436 | console_idx = log_first_idx; | |
1437 | } | |
1438 | ||
1439 | if (console_seq == log_next_seq) | |
1440 | break; | |
1441 | ||
1442 | msg = log_from_idx(console_idx); | |
1443 | level = msg->level & 7; | |
1444 | len = msg->text_len; | |
1445 | if (len+1 >= sizeof(text)) | |
1446 | len = sizeof(text)-1; | |
1447 | memcpy(text, log_text(msg), len); | |
1448 | text[len++] = '\n'; | |
1449 | ||
1450 | console_idx = log_next(console_idx); | |
1451 | console_seq++; | |
07354eb1 | 1452 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 1453 | |
81d68a96 | 1454 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 1455 | call_console_drivers(level, text, len); |
81d68a96 | 1456 | start_critical_timings(); |
1da177e4 LT |
1457 | local_irq_restore(flags); |
1458 | } | |
1459 | console_locked = 0; | |
fe3d8ad3 FT |
1460 | |
1461 | /* Release the exclusive_console once it is used */ | |
1462 | if (unlikely(exclusive_console)) | |
1463 | exclusive_console = NULL; | |
1464 | ||
07354eb1 | 1465 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 1466 | |
0b5e1c52 | 1467 | up(&console_sem); |
4f2a8d3c PZ |
1468 | |
1469 | /* | |
1470 | * Someone could have filled up the buffer again, so re-check if there's | |
1471 | * something to flush. In case we cannot trylock the console_sem again, | |
1472 | * there's a new owner and the console_unlock() from them will do the | |
1473 | * flush, no worries. | |
1474 | */ | |
07354eb1 | 1475 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1476 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
1477 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
1478 | ||
4f2a8d3c PZ |
1479 | if (retry && console_trylock()) |
1480 | goto again; | |
1481 | ||
e3e8a75d KK |
1482 | if (wake_klogd) |
1483 | wake_up_klogd(); | |
1da177e4 | 1484 | } |
ac751efa | 1485 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 1486 | |
ddad86c2 MW |
1487 | /** |
1488 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
1489 | * |
1490 | * If the console code is currently allowed to sleep, and | |
1491 | * if this CPU should yield the CPU to another task, do | |
1492 | * so here. | |
1493 | * | |
ac751efa | 1494 | * Must be called within console_lock();. |
1da177e4 LT |
1495 | */ |
1496 | void __sched console_conditional_schedule(void) | |
1497 | { | |
1498 | if (console_may_schedule) | |
1499 | cond_resched(); | |
1500 | } | |
1501 | EXPORT_SYMBOL(console_conditional_schedule); | |
1502 | ||
1da177e4 LT |
1503 | void console_unblank(void) |
1504 | { | |
1505 | struct console *c; | |
1506 | ||
1507 | /* | |
1508 | * console_unblank can no longer be called in interrupt context unless | |
1509 | * oops_in_progress is set to 1.. | |
1510 | */ | |
1511 | if (oops_in_progress) { | |
1512 | if (down_trylock(&console_sem) != 0) | |
1513 | return; | |
1514 | } else | |
ac751efa | 1515 | console_lock(); |
1da177e4 LT |
1516 | |
1517 | console_locked = 1; | |
1518 | console_may_schedule = 0; | |
4d091611 | 1519 | for_each_console(c) |
1da177e4 LT |
1520 | if ((c->flags & CON_ENABLED) && c->unblank) |
1521 | c->unblank(); | |
ac751efa | 1522 | console_unlock(); |
1da177e4 | 1523 | } |
1da177e4 LT |
1524 | |
1525 | /* | |
1526 | * Return the console tty driver structure and its associated index | |
1527 | */ | |
1528 | struct tty_driver *console_device(int *index) | |
1529 | { | |
1530 | struct console *c; | |
1531 | struct tty_driver *driver = NULL; | |
1532 | ||
ac751efa | 1533 | console_lock(); |
4d091611 | 1534 | for_each_console(c) { |
1da177e4 LT |
1535 | if (!c->device) |
1536 | continue; | |
1537 | driver = c->device(c, index); | |
1538 | if (driver) | |
1539 | break; | |
1540 | } | |
ac751efa | 1541 | console_unlock(); |
1da177e4 LT |
1542 | return driver; |
1543 | } | |
1544 | ||
1545 | /* | |
1546 | * Prevent further output on the passed console device so that (for example) | |
1547 | * serial drivers can disable console output before suspending a port, and can | |
1548 | * re-enable output afterwards. | |
1549 | */ | |
1550 | void console_stop(struct console *console) | |
1551 | { | |
ac751efa | 1552 | console_lock(); |
1da177e4 | 1553 | console->flags &= ~CON_ENABLED; |
ac751efa | 1554 | console_unlock(); |
1da177e4 LT |
1555 | } |
1556 | EXPORT_SYMBOL(console_stop); | |
1557 | ||
1558 | void console_start(struct console *console) | |
1559 | { | |
ac751efa | 1560 | console_lock(); |
1da177e4 | 1561 | console->flags |= CON_ENABLED; |
ac751efa | 1562 | console_unlock(); |
1da177e4 LT |
1563 | } |
1564 | EXPORT_SYMBOL(console_start); | |
1565 | ||
7bf69395 FDN |
1566 | static int __read_mostly keep_bootcon; |
1567 | ||
1568 | static int __init keep_bootcon_setup(char *str) | |
1569 | { | |
1570 | keep_bootcon = 1; | |
1571 | printk(KERN_INFO "debug: skip boot console de-registration.\n"); | |
1572 | ||
1573 | return 0; | |
1574 | } | |
1575 | ||
1576 | early_param("keep_bootcon", keep_bootcon_setup); | |
1577 | ||
1da177e4 LT |
1578 | /* |
1579 | * The console driver calls this routine during kernel initialization | |
1580 | * to register the console printing procedure with printk() and to | |
1581 | * print any messages that were printed by the kernel before the | |
1582 | * console driver was initialized. | |
4d091611 RG |
1583 | * |
1584 | * This can happen pretty early during the boot process (because of | |
1585 | * early_printk) - sometimes before setup_arch() completes - be careful | |
1586 | * of what kernel features are used - they may not be initialised yet. | |
1587 | * | |
1588 | * There are two types of consoles - bootconsoles (early_printk) and | |
1589 | * "real" consoles (everything which is not a bootconsole) which are | |
1590 | * handled differently. | |
1591 | * - Any number of bootconsoles can be registered at any time. | |
1592 | * - As soon as a "real" console is registered, all bootconsoles | |
1593 | * will be unregistered automatically. | |
1594 | * - Once a "real" console is registered, any attempt to register a | |
1595 | * bootconsoles will be rejected | |
1da177e4 | 1596 | */ |
4d091611 | 1597 | void register_console(struct console *newcon) |
1da177e4 | 1598 | { |
40dc5651 | 1599 | int i; |
1da177e4 | 1600 | unsigned long flags; |
4d091611 | 1601 | struct console *bcon = NULL; |
1da177e4 | 1602 | |
4d091611 RG |
1603 | /* |
1604 | * before we register a new CON_BOOT console, make sure we don't | |
1605 | * already have a valid console | |
1606 | */ | |
1607 | if (console_drivers && newcon->flags & CON_BOOT) { | |
1608 | /* find the last or real console */ | |
1609 | for_each_console(bcon) { | |
1610 | if (!(bcon->flags & CON_BOOT)) { | |
1611 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", | |
1612 | newcon->name, newcon->index); | |
1613 | return; | |
1614 | } | |
1615 | } | |
69331af7 GH |
1616 | } |
1617 | ||
4d091611 RG |
1618 | if (console_drivers && console_drivers->flags & CON_BOOT) |
1619 | bcon = console_drivers; | |
1620 | ||
1621 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
1622 | preferred_console = selected_console; |
1623 | ||
4d091611 RG |
1624 | if (newcon->early_setup) |
1625 | newcon->early_setup(); | |
18a8bd94 | 1626 | |
1da177e4 LT |
1627 | /* |
1628 | * See if we want to use this console driver. If we | |
1629 | * didn't select a console we take the first one | |
1630 | * that registers here. | |
1631 | */ | |
1632 | if (preferred_console < 0) { | |
4d091611 RG |
1633 | if (newcon->index < 0) |
1634 | newcon->index = 0; | |
1635 | if (newcon->setup == NULL || | |
1636 | newcon->setup(newcon, NULL) == 0) { | |
1637 | newcon->flags |= CON_ENABLED; | |
1638 | if (newcon->device) { | |
1639 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
1640 | preferred_console = 0; |
1641 | } | |
1da177e4 LT |
1642 | } |
1643 | } | |
1644 | ||
1645 | /* | |
1646 | * See if this console matches one we selected on | |
1647 | * the command line. | |
1648 | */ | |
40dc5651 JJ |
1649 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
1650 | i++) { | |
4d091611 | 1651 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
1da177e4 | 1652 | continue; |
4d091611 RG |
1653 | if (newcon->index >= 0 && |
1654 | newcon->index != console_cmdline[i].index) | |
1da177e4 | 1655 | continue; |
4d091611 RG |
1656 | if (newcon->index < 0) |
1657 | newcon->index = console_cmdline[i].index; | |
f7511d5f ST |
1658 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1659 | if (console_cmdline[i].brl_options) { | |
4d091611 RG |
1660 | newcon->flags |= CON_BRL; |
1661 | braille_register_console(newcon, | |
f7511d5f ST |
1662 | console_cmdline[i].index, |
1663 | console_cmdline[i].options, | |
1664 | console_cmdline[i].brl_options); | |
1665 | return; | |
1666 | } | |
1667 | #endif | |
4d091611 RG |
1668 | if (newcon->setup && |
1669 | newcon->setup(newcon, console_cmdline[i].options) != 0) | |
1da177e4 | 1670 | break; |
4d091611 RG |
1671 | newcon->flags |= CON_ENABLED; |
1672 | newcon->index = console_cmdline[i].index; | |
ab4af03a | 1673 | if (i == selected_console) { |
4d091611 | 1674 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
1675 | preferred_console = selected_console; |
1676 | } | |
1da177e4 LT |
1677 | break; |
1678 | } | |
1679 | ||
4d091611 | 1680 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
1681 | return; |
1682 | ||
8259cf43 RG |
1683 | /* |
1684 | * If we have a bootconsole, and are switching to a real console, | |
1685 | * don't print everything out again, since when the boot console, and | |
1686 | * the real console are the same physical device, it's annoying to | |
1687 | * see the beginning boot messages twice | |
1688 | */ | |
1689 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 1690 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
1691 | |
1692 | /* | |
1693 | * Put this console in the list - keep the | |
1694 | * preferred driver at the head of the list. | |
1695 | */ | |
ac751efa | 1696 | console_lock(); |
4d091611 RG |
1697 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
1698 | newcon->next = console_drivers; | |
1699 | console_drivers = newcon; | |
1700 | if (newcon->next) | |
1701 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 1702 | } else { |
4d091611 RG |
1703 | newcon->next = console_drivers->next; |
1704 | console_drivers->next = newcon; | |
1da177e4 | 1705 | } |
4d091611 | 1706 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 1707 | /* |
ac751efa | 1708 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
1709 | * for us. |
1710 | */ | |
07354eb1 | 1711 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
1712 | console_seq = syslog_seq; |
1713 | console_idx = syslog_idx; | |
07354eb1 | 1714 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
1715 | /* |
1716 | * We're about to replay the log buffer. Only do this to the | |
1717 | * just-registered console to avoid excessive message spam to | |
1718 | * the already-registered consoles. | |
1719 | */ | |
1720 | exclusive_console = newcon; | |
1da177e4 | 1721 | } |
ac751efa | 1722 | console_unlock(); |
fbc92a34 | 1723 | console_sysfs_notify(); |
8259cf43 RG |
1724 | |
1725 | /* | |
1726 | * By unregistering the bootconsoles after we enable the real console | |
1727 | * we get the "console xxx enabled" message on all the consoles - | |
1728 | * boot consoles, real consoles, etc - this is to ensure that end | |
1729 | * users know there might be something in the kernel's log buffer that | |
1730 | * went to the bootconsole (that they do not see on the real console) | |
1731 | */ | |
7bf69395 FDN |
1732 | if (bcon && |
1733 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
1734 | !keep_bootcon) { | |
8259cf43 RG |
1735 | /* we need to iterate through twice, to make sure we print |
1736 | * everything out, before we unregister the console(s) | |
1737 | */ | |
1738 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", | |
1739 | newcon->name, newcon->index); | |
1740 | for_each_console(bcon) | |
1741 | if (bcon->flags & CON_BOOT) | |
1742 | unregister_console(bcon); | |
1743 | } else { | |
1744 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", | |
1745 | (newcon->flags & CON_BOOT) ? "boot" : "" , | |
1746 | newcon->name, newcon->index); | |
1747 | } | |
1da177e4 LT |
1748 | } |
1749 | EXPORT_SYMBOL(register_console); | |
1750 | ||
40dc5651 | 1751 | int unregister_console(struct console *console) |
1da177e4 | 1752 | { |
40dc5651 | 1753 | struct console *a, *b; |
1da177e4 LT |
1754 | int res = 1; |
1755 | ||
f7511d5f ST |
1756 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1757 | if (console->flags & CON_BRL) | |
1758 | return braille_unregister_console(console); | |
1759 | #endif | |
1760 | ||
ac751efa | 1761 | console_lock(); |
1da177e4 LT |
1762 | if (console_drivers == console) { |
1763 | console_drivers=console->next; | |
1764 | res = 0; | |
e9b15b54 | 1765 | } else if (console_drivers) { |
1da177e4 LT |
1766 | for (a=console_drivers->next, b=console_drivers ; |
1767 | a; b=a, a=b->next) { | |
1768 | if (a == console) { | |
1769 | b->next = a->next; | |
1770 | res = 0; | |
1771 | break; | |
40dc5651 | 1772 | } |
1da177e4 LT |
1773 | } |
1774 | } | |
40dc5651 | 1775 | |
69331af7 | 1776 | /* |
ab4af03a GE |
1777 | * If this isn't the last console and it has CON_CONSDEV set, we |
1778 | * need to set it on the next preferred console. | |
1da177e4 | 1779 | */ |
69331af7 | 1780 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 1781 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 1782 | |
ac751efa | 1783 | console_unlock(); |
fbc92a34 | 1784 | console_sysfs_notify(); |
1da177e4 LT |
1785 | return res; |
1786 | } | |
1787 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 1788 | |
034260d6 | 1789 | static int __init printk_late_init(void) |
0c5564bd | 1790 | { |
4d091611 RG |
1791 | struct console *con; |
1792 | ||
1793 | for_each_console(con) { | |
4c30c6f5 | 1794 | if (!keep_bootcon && con->flags & CON_BOOT) { |
cb00e99c | 1795 | printk(KERN_INFO "turn off boot console %s%d\n", |
4d091611 | 1796 | con->name, con->index); |
42c2c8c8 | 1797 | unregister_console(con); |
cb00e99c | 1798 | } |
0c5564bd | 1799 | } |
034260d6 | 1800 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
1801 | return 0; |
1802 | } | |
034260d6 | 1803 | late_initcall(printk_late_init); |
0c5564bd | 1804 | |
7ef3d2fd | 1805 | #if defined CONFIG_PRINTK |
717115e1 | 1806 | |
600e1458 PZ |
1807 | int printk_sched(const char *fmt, ...) |
1808 | { | |
1809 | unsigned long flags; | |
1810 | va_list args; | |
1811 | char *buf; | |
1812 | int r; | |
1813 | ||
1814 | local_irq_save(flags); | |
1815 | buf = __get_cpu_var(printk_sched_buf); | |
1816 | ||
1817 | va_start(args, fmt); | |
1818 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); | |
1819 | va_end(args); | |
1820 | ||
1821 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); | |
1822 | local_irq_restore(flags); | |
1823 | ||
1824 | return r; | |
1825 | } | |
1826 | ||
1da177e4 LT |
1827 | /* |
1828 | * printk rate limiting, lifted from the networking subsystem. | |
1829 | * | |
641de9d8 UKK |
1830 | * This enforces a rate limit: not more than 10 kernel messages |
1831 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 1832 | */ |
641de9d8 UKK |
1833 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
1834 | ||
5c828713 | 1835 | int __printk_ratelimit(const char *func) |
1da177e4 | 1836 | { |
5c828713 | 1837 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 1838 | } |
5c828713 | 1839 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
1840 | |
1841 | /** | |
1842 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
1843 | * @caller_jiffies: pointer to caller's state | |
1844 | * @interval_msecs: minimum interval between prints | |
1845 | * | |
1846 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
1847 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
1848 | * returned true. | |
1849 | */ | |
1850 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
1851 | unsigned int interval_msecs) | |
1852 | { | |
f2d28a2e GK |
1853 | if (*caller_jiffies == 0 |
1854 | || !time_in_range(jiffies, *caller_jiffies, | |
1855 | *caller_jiffies | |
1856 | + msecs_to_jiffies(interval_msecs))) { | |
1857 | *caller_jiffies = jiffies; | |
f46c4833 AM |
1858 | return true; |
1859 | } | |
1860 | return false; | |
1861 | } | |
1862 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
1863 | |
1864 | static DEFINE_SPINLOCK(dump_list_lock); | |
1865 | static LIST_HEAD(dump_list); | |
1866 | ||
1867 | /** | |
1868 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 1869 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
1870 | * |
1871 | * Adds a kernel log dumper to the system. The dump callback in the | |
1872 | * structure will be called when the kernel oopses or panics and must be | |
1873 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
1874 | */ | |
1875 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
1876 | { | |
1877 | unsigned long flags; | |
1878 | int err = -EBUSY; | |
1879 | ||
1880 | /* The dump callback needs to be set */ | |
1881 | if (!dumper->dump) | |
1882 | return -EINVAL; | |
1883 | ||
1884 | spin_lock_irqsave(&dump_list_lock, flags); | |
1885 | /* Don't allow registering multiple times */ | |
1886 | if (!dumper->registered) { | |
1887 | dumper->registered = 1; | |
fb842b00 | 1888 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
1889 | err = 0; |
1890 | } | |
1891 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
1892 | ||
1893 | return err; | |
1894 | } | |
1895 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
1896 | ||
1897 | /** | |
1898 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 1899 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
1900 | * |
1901 | * Removes a dump device from the system. Returns zero on success and | |
1902 | * %-EINVAL otherwise. | |
1903 | */ | |
1904 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
1905 | { | |
1906 | unsigned long flags; | |
1907 | int err = -EINVAL; | |
1908 | ||
1909 | spin_lock_irqsave(&dump_list_lock, flags); | |
1910 | if (dumper->registered) { | |
1911 | dumper->registered = 0; | |
fb842b00 | 1912 | list_del_rcu(&dumper->list); |
456b565c SK |
1913 | err = 0; |
1914 | } | |
1915 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 1916 | synchronize_rcu(); |
456b565c SK |
1917 | |
1918 | return err; | |
1919 | } | |
1920 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
1921 | ||
7ff9554b KS |
1922 | static bool always_kmsg_dump; |
1923 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
1924 | ||
456b565c SK |
1925 | /** |
1926 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
1927 | * @reason: the reason (oops, panic etc) for dumping | |
1928 | * | |
1929 | * Iterate through each of the dump devices and call the oops/panic | |
1930 | * callbacks with the log buffer. | |
1931 | */ | |
1932 | void kmsg_dump(enum kmsg_dump_reason reason) | |
1933 | { | |
7ff9554b | 1934 | u64 idx; |
456b565c SK |
1935 | struct kmsg_dumper *dumper; |
1936 | const char *s1, *s2; | |
1937 | unsigned long l1, l2; | |
1938 | unsigned long flags; | |
1939 | ||
c22ab332 MG |
1940 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
1941 | return; | |
1942 | ||
456b565c SK |
1943 | /* Theoretically, the log could move on after we do this, but |
1944 | there's not a lot we can do about that. The new messages | |
1945 | will overwrite the start of what we dump. */ | |
7ff9554b | 1946 | |
07354eb1 | 1947 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
1948 | if (syslog_seq < log_first_seq) |
1949 | idx = syslog_idx; | |
1950 | else | |
1951 | idx = log_first_idx; | |
456b565c | 1952 | |
7ff9554b KS |
1953 | if (idx > log_next_idx) { |
1954 | s1 = log_buf; | |
1955 | l1 = log_next_idx; | |
456b565c | 1956 | |
7ff9554b KS |
1957 | s2 = log_buf + idx; |
1958 | l2 = log_buf_len - idx; | |
456b565c SK |
1959 | } else { |
1960 | s1 = ""; | |
1961 | l1 = 0; | |
1962 | ||
7ff9554b KS |
1963 | s2 = log_buf + idx; |
1964 | l2 = log_next_idx - idx; | |
456b565c | 1965 | } |
7ff9554b | 1966 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 1967 | |
fb842b00 HY |
1968 | rcu_read_lock(); |
1969 | list_for_each_entry_rcu(dumper, &dump_list, list) | |
456b565c | 1970 | dumper->dump(dumper, reason, s1, l1, s2, l2); |
fb842b00 | 1971 | rcu_read_unlock(); |
456b565c | 1972 | } |
7ef3d2fd | 1973 | #endif |