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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> |
e11fea92 | 44 | #include <linux/poll.h> |
74876a98 | 45 | #include <linux/irq_work.h> |
196779b9 | 46 | #include <linux/utsname.h> |
249771b8 | 47 | #include <linux/ctype.h> |
e2e40f2c | 48 | #include <linux/uio.h> |
1da177e4 LT |
49 | |
50 | #include <asm/uaccess.h> | |
81cc26f2 | 51 | #include <asm-generic/sections.h> |
1da177e4 | 52 | |
95100358 JB |
53 | #define CREATE_TRACE_POINTS |
54 | #include <trace/events/printk.h> | |
55 | ||
d197c43d | 56 | #include "console_cmdline.h" |
bbeddf52 | 57 | #include "braille.h" |
d197c43d | 58 | |
1da177e4 | 59 | int console_printk[4] = { |
a8fe19eb | 60 | CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */ |
42a9dc0b | 61 | MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */ |
a8fe19eb BP |
62 | CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */ |
63 | CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */ | |
1da177e4 LT |
64 | }; |
65 | ||
1da177e4 | 66 | /* |
0bbfb7c2 | 67 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
68 | * their unblank() callback or not. So let's export it. |
69 | */ | |
70 | int oops_in_progress; | |
71 | EXPORT_SYMBOL(oops_in_progress); | |
72 | ||
73 | /* | |
74 | * console_sem protects the console_drivers list, and also | |
75 | * provides serialisation for access to the entire console | |
76 | * driver system. | |
77 | */ | |
5b8c4f23 | 78 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 79 | struct console *console_drivers; |
a29d1cfe IM |
80 | EXPORT_SYMBOL_GPL(console_drivers); |
81 | ||
daee7797 DV |
82 | #ifdef CONFIG_LOCKDEP |
83 | static struct lockdep_map console_lock_dep_map = { | |
84 | .name = "console_lock" | |
85 | }; | |
86 | #endif | |
87 | ||
6fe29354 TH |
88 | /* |
89 | * Number of registered extended console drivers. | |
90 | * | |
91 | * If extended consoles are present, in-kernel cont reassembly is disabled | |
92 | * and each fragment is stored as a separate log entry with proper | |
93 | * continuation flag so that every emitted message has full metadata. This | |
94 | * doesn't change the result for regular consoles or /proc/kmsg. For | |
95 | * /dev/kmsg, as long as the reader concatenates messages according to | |
96 | * consecutive continuation flags, the end result should be the same too. | |
97 | */ | |
98 | static int nr_ext_console_drivers; | |
99 | ||
bd8d7cf5 JK |
100 | /* |
101 | * Helper macros to handle lockdep when locking/unlocking console_sem. We use | |
102 | * macros instead of functions so that _RET_IP_ contains useful information. | |
103 | */ | |
104 | #define down_console_sem() do { \ | |
105 | down(&console_sem);\ | |
106 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\ | |
107 | } while (0) | |
108 | ||
109 | static int __down_trylock_console_sem(unsigned long ip) | |
110 | { | |
111 | if (down_trylock(&console_sem)) | |
112 | return 1; | |
113 | mutex_acquire(&console_lock_dep_map, 0, 1, ip); | |
114 | return 0; | |
115 | } | |
116 | #define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_) | |
117 | ||
118 | #define up_console_sem() do { \ | |
119 | mutex_release(&console_lock_dep_map, 1, _RET_IP_);\ | |
120 | up(&console_sem);\ | |
121 | } while (0) | |
122 | ||
1da177e4 LT |
123 | /* |
124 | * This is used for debugging the mess that is the VT code by | |
125 | * keeping track if we have the console semaphore held. It's | |
126 | * definitely not the perfect debug tool (we don't know if _WE_ | |
0b90fec3 AE |
127 | * hold it and are racing, but it helps tracking those weird code |
128 | * paths in the console code where we end up in places I want | |
129 | * locked without the console sempahore held). | |
1da177e4 | 130 | */ |
557240b4 | 131 | static int console_locked, console_suspended; |
1da177e4 | 132 | |
fe3d8ad3 FT |
133 | /* |
134 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
135 | */ | |
136 | static struct console *exclusive_console; | |
137 | ||
1da177e4 LT |
138 | /* |
139 | * Array of consoles built from command line options (console=) | |
140 | */ | |
1da177e4 LT |
141 | |
142 | #define MAX_CMDLINECONSOLES 8 | |
143 | ||
144 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
d197c43d | 145 | |
1da177e4 LT |
146 | static int selected_console = -1; |
147 | static int preferred_console = -1; | |
9e124fe1 MA |
148 | int console_set_on_cmdline; |
149 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
150 | |
151 | /* Flag: console code may call schedule() */ | |
152 | static int console_may_schedule; | |
153 | ||
7ff9554b KS |
154 | /* |
155 | * The printk log buffer consists of a chain of concatenated variable | |
156 | * length records. Every record starts with a record header, containing | |
157 | * the overall length of the record. | |
158 | * | |
159 | * The heads to the first and last entry in the buffer, as well as the | |
0b90fec3 AE |
160 | * sequence numbers of these entries are maintained when messages are |
161 | * stored. | |
7ff9554b KS |
162 | * |
163 | * If the heads indicate available messages, the length in the header | |
164 | * tells the start next message. A length == 0 for the next message | |
165 | * indicates a wrap-around to the beginning of the buffer. | |
166 | * | |
167 | * Every record carries the monotonic timestamp in microseconds, as well as | |
168 | * the standard userspace syslog level and syslog facility. The usual | |
169 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
170 | * a matching syslog facility, by default LOG_USER. The origin of every | |
171 | * message can be reliably determined that way. | |
172 | * | |
173 | * The human readable log message directly follows the message header. The | |
174 | * length of the message text is stored in the header, the stored message | |
175 | * is not terminated. | |
176 | * | |
e11fea92 KS |
177 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
178 | * to provide userspace with a machine-readable message context. | |
179 | * | |
180 | * Examples for well-defined, commonly used property names are: | |
181 | * DEVICE=b12:8 device identifier | |
182 | * b12:8 block dev_t | |
183 | * c127:3 char dev_t | |
184 | * n8 netdev ifindex | |
185 | * +sound:card0 subsystem:devname | |
186 | * SUBSYSTEM=pci driver-core subsystem name | |
187 | * | |
188 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
189 | * follows directly after a '=' character. Every property is terminated by | |
190 | * a '\0' character. The last property is not terminated. | |
191 | * | |
192 | * Example of a message structure: | |
193 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
194 | * 0008 34 00 record is 52 bytes long | |
195 | * 000a 0b 00 text is 11 bytes long | |
196 | * 000c 1f 00 dictionary is 23 bytes long | |
197 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
198 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
199 | * 69 6e 65 "ine" | |
200 | * 001b 44 45 56 49 43 "DEVIC" | |
201 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
202 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
203 | * 67 "g" | |
204 | * 0032 00 00 00 padding to next message header | |
205 | * | |
62e32ac3 | 206 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
207 | * userspace, it is a kernel-private implementation detail that might |
208 | * need to be changed in the future, when the requirements change. | |
209 | * | |
210 | * /dev/kmsg exports the structured data in the following line format: | |
b389645f AO |
211 | * "<level>,<sequnum>,<timestamp>,<contflag>[,additional_values, ... ];<message text>\n" |
212 | * | |
213 | * Users of the export format should ignore possible additional values | |
214 | * separated by ',', and find the message after the ';' character. | |
e11fea92 KS |
215 | * |
216 | * The optional key/value pairs are attached as continuation lines starting | |
217 | * with a space character and terminated by a newline. All possible | |
218 | * non-prinatable characters are escaped in the "\xff" notation. | |
7ff9554b KS |
219 | */ |
220 | ||
084681d1 | 221 | enum log_flags { |
5becfb1d KS |
222 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
223 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
224 | LOG_PREFIX = 4, /* text started with a prefix */ | |
225 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
226 | }; |
227 | ||
62e32ac3 | 228 | struct printk_log { |
7ff9554b KS |
229 | u64 ts_nsec; /* timestamp in nanoseconds */ |
230 | u16 len; /* length of entire record */ | |
231 | u16 text_len; /* length of text buffer */ | |
232 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
233 | u8 facility; /* syslog facility */ |
234 | u8 flags:5; /* internal record flags */ | |
235 | u8 level:3; /* syslog level */ | |
5c9cf8af AR |
236 | } |
237 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS | |
238 | __packed __aligned(4) | |
239 | #endif | |
240 | ; | |
7ff9554b KS |
241 | |
242 | /* | |
458df9fd SR |
243 | * The logbuf_lock protects kmsg buffer, indices, counters. This can be taken |
244 | * within the scheduler's rq lock. It must be released before calling | |
245 | * console_unlock() or anything else that might wake up a process. | |
7ff9554b KS |
246 | */ |
247 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 248 | |
96efedf1 | 249 | #ifdef CONFIG_PRINTK |
dc72c32e | 250 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
251 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
252 | static u64 syslog_seq; | |
253 | static u32 syslog_idx; | |
5becfb1d | 254 | static enum log_flags syslog_prev; |
eb02dac9 | 255 | static size_t syslog_partial; |
7ff9554b KS |
256 | |
257 | /* index and sequence number of the first record stored in the buffer */ | |
258 | static u64 log_first_seq; | |
259 | static u32 log_first_idx; | |
260 | ||
261 | /* index and sequence number of the next record to store in the buffer */ | |
262 | static u64 log_next_seq; | |
263 | static u32 log_next_idx; | |
264 | ||
eab07260 KS |
265 | /* the next printk record to write to the console */ |
266 | static u64 console_seq; | |
267 | static u32 console_idx; | |
268 | static enum log_flags console_prev; | |
269 | ||
7ff9554b KS |
270 | /* the next printk record to read after the last 'clear' command */ |
271 | static u64 clear_seq; | |
272 | static u32 clear_idx; | |
273 | ||
70498253 | 274 | #define PREFIX_MAX 32 |
249771b8 | 275 | #define LOG_LINE_MAX (1024 - PREFIX_MAX) |
7f3a781d | 276 | |
3824657c MK |
277 | #define LOG_LEVEL(v) ((v) & 0x07) |
278 | #define LOG_FACILITY(v) ((v) >> 3 & 0xff) | |
279 | ||
7f3a781d | 280 | /* record buffer */ |
62e32ac3 | 281 | #define LOG_ALIGN __alignof__(struct printk_log) |
7f3a781d | 282 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 283 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
284 | static char *log_buf = __log_buf; |
285 | static u32 log_buf_len = __LOG_BUF_LEN; | |
286 | ||
14c4000a VH |
287 | /* Return log buffer address */ |
288 | char *log_buf_addr_get(void) | |
289 | { | |
290 | return log_buf; | |
291 | } | |
292 | ||
293 | /* Return log buffer size */ | |
294 | u32 log_buf_len_get(void) | |
295 | { | |
296 | return log_buf_len; | |
297 | } | |
298 | ||
7ff9554b | 299 | /* human readable text of the record */ |
62e32ac3 | 300 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 301 | { |
62e32ac3 | 302 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
303 | } |
304 | ||
305 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 306 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 307 | { |
62e32ac3 | 308 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
309 | } |
310 | ||
311 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 312 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 313 | { |
62e32ac3 | 314 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
315 | |
316 | /* | |
317 | * A length == 0 record is the end of buffer marker. Wrap around and | |
318 | * read the message at the start of the buffer. | |
319 | */ | |
320 | if (!msg->len) | |
62e32ac3 | 321 | return (struct printk_log *)log_buf; |
7ff9554b KS |
322 | return msg; |
323 | } | |
324 | ||
325 | /* get next record; idx must point to valid msg */ | |
326 | static u32 log_next(u32 idx) | |
327 | { | |
62e32ac3 | 328 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
329 | |
330 | /* length == 0 indicates the end of the buffer; wrap */ | |
331 | /* | |
332 | * A length == 0 record is the end of buffer marker. Wrap around and | |
333 | * read the message at the start of the buffer as *this* one, and | |
334 | * return the one after that. | |
335 | */ | |
336 | if (!msg->len) { | |
62e32ac3 | 337 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
338 | return msg->len; |
339 | } | |
340 | return idx + msg->len; | |
341 | } | |
342 | ||
f40e4b9f PM |
343 | /* |
344 | * Check whether there is enough free space for the given message. | |
345 | * | |
346 | * The same values of first_idx and next_idx mean that the buffer | |
347 | * is either empty or full. | |
348 | * | |
349 | * If the buffer is empty, we must respect the position of the indexes. | |
350 | * They cannot be reset to the beginning of the buffer. | |
351 | */ | |
352 | static int logbuf_has_space(u32 msg_size, bool empty) | |
0a581694 PM |
353 | { |
354 | u32 free; | |
355 | ||
f40e4b9f | 356 | if (log_next_idx > log_first_idx || empty) |
0a581694 PM |
357 | free = max(log_buf_len - log_next_idx, log_first_idx); |
358 | else | |
359 | free = log_first_idx - log_next_idx; | |
360 | ||
361 | /* | |
362 | * We need space also for an empty header that signalizes wrapping | |
363 | * of the buffer. | |
364 | */ | |
365 | return free >= msg_size + sizeof(struct printk_log); | |
366 | } | |
367 | ||
f40e4b9f | 368 | static int log_make_free_space(u32 msg_size) |
0a581694 | 369 | { |
f468908b ID |
370 | while (log_first_seq < log_next_seq && |
371 | !logbuf_has_space(msg_size, false)) { | |
0b90fec3 | 372 | /* drop old messages until we have enough contiguous space */ |
0a581694 PM |
373 | log_first_idx = log_next(log_first_idx); |
374 | log_first_seq++; | |
375 | } | |
f40e4b9f | 376 | |
f468908b ID |
377 | if (clear_seq < log_first_seq) { |
378 | clear_seq = log_first_seq; | |
379 | clear_idx = log_first_idx; | |
380 | } | |
381 | ||
f40e4b9f | 382 | /* sequence numbers are equal, so the log buffer is empty */ |
f468908b | 383 | if (logbuf_has_space(msg_size, log_first_seq == log_next_seq)) |
f40e4b9f PM |
384 | return 0; |
385 | ||
386 | return -ENOMEM; | |
0a581694 PM |
387 | } |
388 | ||
85c87043 PM |
389 | /* compute the message size including the padding bytes */ |
390 | static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) | |
391 | { | |
392 | u32 size; | |
393 | ||
394 | size = sizeof(struct printk_log) + text_len + dict_len; | |
395 | *pad_len = (-size) & (LOG_ALIGN - 1); | |
396 | size += *pad_len; | |
397 | ||
398 | return size; | |
399 | } | |
400 | ||
55bd53a4 PM |
401 | /* |
402 | * Define how much of the log buffer we could take at maximum. The value | |
403 | * must be greater than two. Note that only half of the buffer is available | |
404 | * when the index points to the middle. | |
405 | */ | |
406 | #define MAX_LOG_TAKE_PART 4 | |
407 | static const char trunc_msg[] = "<truncated>"; | |
408 | ||
409 | static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len, | |
410 | u16 *dict_len, u32 *pad_len) | |
411 | { | |
412 | /* | |
413 | * The message should not take the whole buffer. Otherwise, it might | |
414 | * get removed too soon. | |
415 | */ | |
416 | u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART; | |
417 | if (*text_len > max_text_len) | |
418 | *text_len = max_text_len; | |
419 | /* enable the warning message */ | |
420 | *trunc_msg_len = strlen(trunc_msg); | |
421 | /* disable the "dict" completely */ | |
422 | *dict_len = 0; | |
423 | /* compute the size again, count also the warning message */ | |
424 | return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len); | |
425 | } | |
426 | ||
7ff9554b | 427 | /* insert record into the buffer, discard old ones, update heads */ |
034633cc PM |
428 | static int log_store(int facility, int level, |
429 | enum log_flags flags, u64 ts_nsec, | |
430 | const char *dict, u16 dict_len, | |
431 | const char *text, u16 text_len) | |
7ff9554b | 432 | { |
62e32ac3 | 433 | struct printk_log *msg; |
7ff9554b | 434 | u32 size, pad_len; |
55bd53a4 | 435 | u16 trunc_msg_len = 0; |
7ff9554b KS |
436 | |
437 | /* number of '\0' padding bytes to next message */ | |
85c87043 | 438 | size = msg_used_size(text_len, dict_len, &pad_len); |
7ff9554b | 439 | |
55bd53a4 PM |
440 | if (log_make_free_space(size)) { |
441 | /* truncate the message if it is too long for empty buffer */ | |
442 | size = truncate_msg(&text_len, &trunc_msg_len, | |
443 | &dict_len, &pad_len); | |
444 | /* survive when the log buffer is too small for trunc_msg */ | |
445 | if (log_make_free_space(size)) | |
034633cc | 446 | return 0; |
55bd53a4 | 447 | } |
7ff9554b | 448 | |
39b25109 | 449 | if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) { |
7ff9554b KS |
450 | /* |
451 | * This message + an additional empty header does not fit | |
452 | * at the end of the buffer. Add an empty header with len == 0 | |
453 | * to signify a wrap around. | |
454 | */ | |
62e32ac3 | 455 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
456 | log_next_idx = 0; |
457 | } | |
458 | ||
459 | /* fill message */ | |
62e32ac3 | 460 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
461 | memcpy(log_text(msg), text, text_len); |
462 | msg->text_len = text_len; | |
55bd53a4 PM |
463 | if (trunc_msg_len) { |
464 | memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len); | |
465 | msg->text_len += trunc_msg_len; | |
466 | } | |
7ff9554b KS |
467 | memcpy(log_dict(msg), dict, dict_len); |
468 | msg->dict_len = dict_len; | |
084681d1 KS |
469 | msg->facility = facility; |
470 | msg->level = level & 7; | |
471 | msg->flags = flags & 0x1f; | |
472 | if (ts_nsec > 0) | |
473 | msg->ts_nsec = ts_nsec; | |
474 | else | |
475 | msg->ts_nsec = local_clock(); | |
7ff9554b | 476 | memset(log_dict(msg) + dict_len, 0, pad_len); |
fce6e033 | 477 | msg->len = size; |
7ff9554b KS |
478 | |
479 | /* insert message */ | |
480 | log_next_idx += msg->len; | |
481 | log_next_seq++; | |
034633cc PM |
482 | |
483 | return msg->text_len; | |
7ff9554b | 484 | } |
d59745ce | 485 | |
e99aa461 | 486 | int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); |
637241a9 KC |
487 | |
488 | static int syslog_action_restricted(int type) | |
489 | { | |
490 | if (dmesg_restrict) | |
491 | return 1; | |
492 | /* | |
493 | * Unless restricted, we allow "read all" and "get buffer size" | |
494 | * for everybody. | |
495 | */ | |
496 | return type != SYSLOG_ACTION_READ_ALL && | |
497 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
498 | } | |
499 | ||
3ea4331c | 500 | int check_syslog_permissions(int type, int source) |
637241a9 KC |
501 | { |
502 | /* | |
503 | * If this is from /proc/kmsg and we've already opened it, then we've | |
504 | * already done the capabilities checks at open time. | |
505 | */ | |
3ea4331c | 506 | if (source == SYSLOG_FROM_PROC && type != SYSLOG_ACTION_OPEN) |
d194e5d6 | 507 | goto ok; |
637241a9 KC |
508 | |
509 | if (syslog_action_restricted(type)) { | |
510 | if (capable(CAP_SYSLOG)) | |
d194e5d6 | 511 | goto ok; |
637241a9 KC |
512 | /* |
513 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
514 | * a warning. | |
515 | */ | |
516 | if (capable(CAP_SYS_ADMIN)) { | |
517 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
518 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
519 | "(deprecated).\n", | |
520 | current->comm, task_pid_nr(current)); | |
d194e5d6 | 521 | goto ok; |
637241a9 KC |
522 | } |
523 | return -EPERM; | |
524 | } | |
d194e5d6 | 525 | ok: |
637241a9 KC |
526 | return security_syslog(type); |
527 | } | |
ee1d2674 | 528 | EXPORT_SYMBOL_GPL(check_syslog_permissions); |
637241a9 | 529 | |
d43ff430 TH |
530 | static void append_char(char **pp, char *e, char c) |
531 | { | |
532 | if (*pp < e) | |
533 | *(*pp)++ = c; | |
534 | } | |
637241a9 | 535 | |
0a295e67 TH |
536 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
537 | struct printk_log *msg, u64 seq, | |
538 | enum log_flags prev_flags) | |
539 | { | |
540 | u64 ts_usec = msg->ts_nsec; | |
541 | char cont = '-'; | |
542 | ||
543 | do_div(ts_usec, 1000); | |
544 | ||
545 | /* | |
546 | * If we couldn't merge continuation line fragments during the print, | |
547 | * export the stored flags to allow an optional external merge of the | |
548 | * records. Merging the records isn't always neccessarily correct, like | |
549 | * when we hit a race during printing. In most cases though, it produces | |
550 | * better readable output. 'c' in the record flags mark the first | |
551 | * fragment of a line, '+' the following. | |
552 | */ | |
553 | if (msg->flags & LOG_CONT && !(prev_flags & LOG_CONT)) | |
554 | cont = 'c'; | |
555 | else if ((msg->flags & LOG_CONT) || | |
556 | ((prev_flags & LOG_CONT) && !(msg->flags & LOG_PREFIX))) | |
557 | cont = '+'; | |
558 | ||
559 | return scnprintf(buf, size, "%u,%llu,%llu,%c;", | |
560 | (msg->facility << 3) | msg->level, seq, ts_usec, cont); | |
561 | } | |
562 | ||
563 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
564 | char *dict, size_t dict_len, | |
565 | char *text, size_t text_len) | |
566 | { | |
567 | char *p = buf, *e = buf + size; | |
568 | size_t i; | |
569 | ||
570 | /* escape non-printable characters */ | |
571 | for (i = 0; i < text_len; i++) { | |
572 | unsigned char c = text[i]; | |
573 | ||
574 | if (c < ' ' || c >= 127 || c == '\\') | |
575 | p += scnprintf(p, e - p, "\\x%02x", c); | |
576 | else | |
577 | append_char(&p, e, c); | |
578 | } | |
579 | append_char(&p, e, '\n'); | |
580 | ||
581 | if (dict_len) { | |
582 | bool line = true; | |
583 | ||
584 | for (i = 0; i < dict_len; i++) { | |
585 | unsigned char c = dict[i]; | |
586 | ||
587 | if (line) { | |
588 | append_char(&p, e, ' '); | |
589 | line = false; | |
590 | } | |
591 | ||
592 | if (c == '\0') { | |
593 | append_char(&p, e, '\n'); | |
594 | line = true; | |
595 | continue; | |
596 | } | |
597 | ||
598 | if (c < ' ' || c >= 127 || c == '\\') { | |
599 | p += scnprintf(p, e - p, "\\x%02x", c); | |
600 | continue; | |
601 | } | |
602 | ||
603 | append_char(&p, e, c); | |
604 | } | |
605 | append_char(&p, e, '\n'); | |
606 | } | |
607 | ||
608 | return p - buf; | |
609 | } | |
610 | ||
e11fea92 KS |
611 | /* /dev/kmsg - userspace message inject/listen interface */ |
612 | struct devkmsg_user { | |
613 | u64 seq; | |
614 | u32 idx; | |
d39f3d77 | 615 | enum log_flags prev; |
e11fea92 | 616 | struct mutex lock; |
d43ff430 | 617 | char buf[CONSOLE_EXT_LOG_MAX]; |
e11fea92 KS |
618 | }; |
619 | ||
849f3127 | 620 | static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) |
e11fea92 KS |
621 | { |
622 | char *buf, *line; | |
e11fea92 KS |
623 | int level = default_message_loglevel; |
624 | int facility = 1; /* LOG_USER */ | |
66ee59af | 625 | size_t len = iov_iter_count(from); |
e11fea92 KS |
626 | ssize_t ret = len; |
627 | ||
628 | if (len > LOG_LINE_MAX) | |
629 | return -EINVAL; | |
630 | buf = kmalloc(len+1, GFP_KERNEL); | |
631 | if (buf == NULL) | |
632 | return -ENOMEM; | |
633 | ||
849f3127 AV |
634 | buf[len] = '\0'; |
635 | if (copy_from_iter(buf, len, from) != len) { | |
636 | kfree(buf); | |
637 | return -EFAULT; | |
e11fea92 KS |
638 | } |
639 | ||
640 | /* | |
641 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
642 | * the decimal value represents 32bit, the lower 3 bit are the log | |
643 | * level, the rest are the log facility. | |
644 | * | |
645 | * If no prefix or no userspace facility is specified, we | |
646 | * enforce LOG_USER, to be able to reliably distinguish | |
647 | * kernel-generated messages from userspace-injected ones. | |
648 | */ | |
649 | line = buf; | |
650 | if (line[0] == '<') { | |
651 | char *endp = NULL; | |
3824657c | 652 | unsigned int u; |
e11fea92 | 653 | |
3824657c | 654 | u = simple_strtoul(line + 1, &endp, 10); |
e11fea92 | 655 | if (endp && endp[0] == '>') { |
3824657c MK |
656 | level = LOG_LEVEL(u); |
657 | if (LOG_FACILITY(u) != 0) | |
658 | facility = LOG_FACILITY(u); | |
e11fea92 KS |
659 | endp++; |
660 | len -= endp - line; | |
661 | line = endp; | |
662 | } | |
663 | } | |
e11fea92 KS |
664 | |
665 | printk_emit(facility, level, NULL, 0, "%s", line); | |
e11fea92 KS |
666 | kfree(buf); |
667 | return ret; | |
668 | } | |
669 | ||
670 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
671 | size_t count, loff_t *ppos) | |
672 | { | |
673 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 674 | struct printk_log *msg; |
e11fea92 KS |
675 | size_t len; |
676 | ssize_t ret; | |
677 | ||
678 | if (!user) | |
679 | return -EBADF; | |
680 | ||
4a77a5a0 YL |
681 | ret = mutex_lock_interruptible(&user->lock); |
682 | if (ret) | |
683 | return ret; | |
5c53d819 | 684 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
685 | while (user->seq == log_next_seq) { |
686 | if (file->f_flags & O_NONBLOCK) { | |
687 | ret = -EAGAIN; | |
5c53d819 | 688 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
689 | goto out; |
690 | } | |
691 | ||
5c53d819 | 692 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
693 | ret = wait_event_interruptible(log_wait, |
694 | user->seq != log_next_seq); | |
695 | if (ret) | |
696 | goto out; | |
5c53d819 | 697 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
698 | } |
699 | ||
700 | if (user->seq < log_first_seq) { | |
701 | /* our last seen message is gone, return error and reset */ | |
702 | user->idx = log_first_idx; | |
703 | user->seq = log_first_seq; | |
704 | ret = -EPIPE; | |
5c53d819 | 705 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
706 | goto out; |
707 | } | |
708 | ||
709 | msg = log_from_idx(user->idx); | |
0a295e67 TH |
710 | len = msg_print_ext_header(user->buf, sizeof(user->buf), |
711 | msg, user->seq, user->prev); | |
712 | len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len, | |
713 | log_dict(msg), msg->dict_len, | |
714 | log_text(msg), msg->text_len); | |
d39f3d77 | 715 | |
d39f3d77 | 716 | user->prev = msg->flags; |
e11fea92 KS |
717 | user->idx = log_next(user->idx); |
718 | user->seq++; | |
5c53d819 | 719 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
720 | |
721 | if (len > count) { | |
722 | ret = -EINVAL; | |
723 | goto out; | |
724 | } | |
725 | ||
726 | if (copy_to_user(buf, user->buf, len)) { | |
727 | ret = -EFAULT; | |
728 | goto out; | |
729 | } | |
730 | ret = len; | |
731 | out: | |
732 | mutex_unlock(&user->lock); | |
733 | return ret; | |
734 | } | |
735 | ||
736 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
737 | { | |
738 | struct devkmsg_user *user = file->private_data; | |
739 | loff_t ret = 0; | |
740 | ||
741 | if (!user) | |
742 | return -EBADF; | |
743 | if (offset) | |
744 | return -ESPIPE; | |
745 | ||
5c53d819 | 746 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
747 | switch (whence) { |
748 | case SEEK_SET: | |
749 | /* the first record */ | |
750 | user->idx = log_first_idx; | |
751 | user->seq = log_first_seq; | |
752 | break; | |
753 | case SEEK_DATA: | |
754 | /* | |
755 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
756 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
757 | * changes no global state, and does not clear anything. | |
758 | */ | |
759 | user->idx = clear_idx; | |
760 | user->seq = clear_seq; | |
761 | break; | |
762 | case SEEK_END: | |
763 | /* after the last record */ | |
764 | user->idx = log_next_idx; | |
765 | user->seq = log_next_seq; | |
766 | break; | |
767 | default: | |
768 | ret = -EINVAL; | |
769 | } | |
5c53d819 | 770 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
771 | return ret; |
772 | } | |
773 | ||
774 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
775 | { | |
776 | struct devkmsg_user *user = file->private_data; | |
777 | int ret = 0; | |
778 | ||
779 | if (!user) | |
780 | return POLLERR|POLLNVAL; | |
781 | ||
782 | poll_wait(file, &log_wait, wait); | |
783 | ||
5c53d819 | 784 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
785 | if (user->seq < log_next_seq) { |
786 | /* return error when data has vanished underneath us */ | |
787 | if (user->seq < log_first_seq) | |
788 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
789 | else |
790 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 791 | } |
5c53d819 | 792 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
793 | |
794 | return ret; | |
795 | } | |
796 | ||
797 | static int devkmsg_open(struct inode *inode, struct file *file) | |
798 | { | |
799 | struct devkmsg_user *user; | |
800 | int err; | |
801 | ||
802 | /* write-only does not need any file context */ | |
803 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
804 | return 0; | |
805 | ||
637241a9 KC |
806 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
807 | SYSLOG_FROM_READER); | |
e11fea92 KS |
808 | if (err) |
809 | return err; | |
810 | ||
811 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
812 | if (!user) | |
813 | return -ENOMEM; | |
814 | ||
815 | mutex_init(&user->lock); | |
816 | ||
5c53d819 | 817 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
818 | user->idx = log_first_idx; |
819 | user->seq = log_first_seq; | |
5c53d819 | 820 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
821 | |
822 | file->private_data = user; | |
823 | return 0; | |
824 | } | |
825 | ||
826 | static int devkmsg_release(struct inode *inode, struct file *file) | |
827 | { | |
828 | struct devkmsg_user *user = file->private_data; | |
829 | ||
830 | if (!user) | |
831 | return 0; | |
832 | ||
833 | mutex_destroy(&user->lock); | |
834 | kfree(user); | |
835 | return 0; | |
836 | } | |
837 | ||
838 | const struct file_operations kmsg_fops = { | |
839 | .open = devkmsg_open, | |
840 | .read = devkmsg_read, | |
849f3127 | 841 | .write_iter = devkmsg_write, |
e11fea92 KS |
842 | .llseek = devkmsg_llseek, |
843 | .poll = devkmsg_poll, | |
844 | .release = devkmsg_release, | |
845 | }; | |
846 | ||
2965faa5 | 847 | #ifdef CONFIG_KEXEC_CORE |
04d491ab | 848 | /* |
4c1ace64 | 849 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 850 | * |
4c1ace64 | 851 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
852 | * obtain access to symbols that are otherwise very difficult to locate. These |
853 | * symbols are specifically used so that utilities can access and extract the | |
854 | * dmesg log from a vmcore file after a crash. | |
855 | */ | |
856 | void log_buf_kexec_setup(void) | |
857 | { | |
858 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 859 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b | 860 | VMCOREINFO_SYMBOL(log_first_idx); |
f468908b | 861 | VMCOREINFO_SYMBOL(clear_idx); |
7ff9554b | 862 | VMCOREINFO_SYMBOL(log_next_idx); |
6791457a | 863 | /* |
62e32ac3 | 864 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
865 | * parse it and detect any changes to structure down the line. |
866 | */ | |
62e32ac3 JP |
867 | VMCOREINFO_STRUCT_SIZE(printk_log); |
868 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
869 | VMCOREINFO_OFFSET(printk_log, len); | |
870 | VMCOREINFO_OFFSET(printk_log, text_len); | |
871 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
872 | } |
873 | #endif | |
874 | ||
162a7e75 MT |
875 | /* requested log_buf_len from kernel cmdline */ |
876 | static unsigned long __initdata new_log_buf_len; | |
877 | ||
c0a318a3 LR |
878 | /* we practice scaling the ring buffer by powers of 2 */ |
879 | static void __init log_buf_len_update(unsigned size) | |
1da177e4 | 880 | { |
1da177e4 LT |
881 | if (size) |
882 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
883 | if (size > log_buf_len) |
884 | new_log_buf_len = size; | |
c0a318a3 LR |
885 | } |
886 | ||
887 | /* save requested log_buf_len since it's too early to process it */ | |
888 | static int __init log_buf_len_setup(char *str) | |
889 | { | |
890 | unsigned size = memparse(str, &str); | |
891 | ||
892 | log_buf_len_update(size); | |
162a7e75 MT |
893 | |
894 | return 0; | |
1da177e4 | 895 | } |
162a7e75 MT |
896 | early_param("log_buf_len", log_buf_len_setup); |
897 | ||
2240a31d GU |
898 | #ifdef CONFIG_SMP |
899 | #define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT) | |
900 | ||
23b2899f LR |
901 | static void __init log_buf_add_cpu(void) |
902 | { | |
903 | unsigned int cpu_extra; | |
904 | ||
905 | /* | |
906 | * archs should set up cpu_possible_bits properly with | |
907 | * set_cpu_possible() after setup_arch() but just in | |
908 | * case lets ensure this is valid. | |
909 | */ | |
910 | if (num_possible_cpus() == 1) | |
911 | return; | |
912 | ||
913 | cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; | |
914 | ||
915 | /* by default this will only continue through for large > 64 CPUs */ | |
916 | if (cpu_extra <= __LOG_BUF_LEN / 2) | |
917 | return; | |
918 | ||
919 | pr_info("log_buf_len individual max cpu contribution: %d bytes\n", | |
920 | __LOG_CPU_MAX_BUF_LEN); | |
921 | pr_info("log_buf_len total cpu_extra contributions: %d bytes\n", | |
922 | cpu_extra); | |
923 | pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN); | |
924 | ||
925 | log_buf_len_update(cpu_extra + __LOG_BUF_LEN); | |
926 | } | |
2240a31d GU |
927 | #else /* !CONFIG_SMP */ |
928 | static inline void log_buf_add_cpu(void) {} | |
929 | #endif /* CONFIG_SMP */ | |
23b2899f | 930 | |
162a7e75 MT |
931 | void __init setup_log_buf(int early) |
932 | { | |
933 | unsigned long flags; | |
162a7e75 MT |
934 | char *new_log_buf; |
935 | int free; | |
936 | ||
23b2899f LR |
937 | if (log_buf != __log_buf) |
938 | return; | |
939 | ||
940 | if (!early && !new_log_buf_len) | |
941 | log_buf_add_cpu(); | |
942 | ||
162a7e75 MT |
943 | if (!new_log_buf_len) |
944 | return; | |
1da177e4 | 945 | |
162a7e75 | 946 | if (early) { |
9da791df | 947 | new_log_buf = |
70300177 | 948 | memblock_virt_alloc(new_log_buf_len, LOG_ALIGN); |
162a7e75 | 949 | } else { |
70300177 LR |
950 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, |
951 | LOG_ALIGN); | |
162a7e75 MT |
952 | } |
953 | ||
954 | if (unlikely(!new_log_buf)) { | |
955 | pr_err("log_buf_len: %ld bytes not available\n", | |
956 | new_log_buf_len); | |
957 | return; | |
958 | } | |
959 | ||
07354eb1 | 960 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
961 | log_buf_len = new_log_buf_len; |
962 | log_buf = new_log_buf; | |
963 | new_log_buf_len = 0; | |
7ff9554b KS |
964 | free = __LOG_BUF_LEN - log_next_idx; |
965 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 966 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 | 967 | |
f5405172 | 968 | pr_info("log_buf_len: %d bytes\n", log_buf_len); |
162a7e75 MT |
969 | pr_info("early log buf free: %d(%d%%)\n", |
970 | free, (free * 100) / __LOG_BUF_LEN); | |
971 | } | |
1da177e4 | 972 | |
2fa72c8f AC |
973 | static bool __read_mostly ignore_loglevel; |
974 | ||
975 | static int __init ignore_loglevel_setup(char *str) | |
976 | { | |
d25d9fec | 977 | ignore_loglevel = true; |
27083bac | 978 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
979 | |
980 | return 0; | |
981 | } | |
982 | ||
983 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
984 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
205bd3d2 JP |
985 | MODULE_PARM_DESC(ignore_loglevel, |
986 | "ignore loglevel setting (prints all kernel messages to the console)"); | |
2fa72c8f | 987 | |
bfe8df3d RD |
988 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
989 | ||
674dff65 | 990 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 991 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
992 | |
993 | static int __init boot_delay_setup(char *str) | |
994 | { | |
995 | unsigned long lpj; | |
bfe8df3d RD |
996 | |
997 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
998 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
999 | ||
1000 | get_option(&str, &boot_delay); | |
1001 | if (boot_delay > 10 * 1000) | |
1002 | boot_delay = 0; | |
1003 | ||
3a3b6ed2 DY |
1004 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
1005 | "HZ: %d, loops_per_msec: %llu\n", | |
1006 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 1007 | return 0; |
bfe8df3d | 1008 | } |
29e9d225 | 1009 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 1010 | |
2fa72c8f | 1011 | static void boot_delay_msec(int level) |
bfe8df3d RD |
1012 | { |
1013 | unsigned long long k; | |
1014 | unsigned long timeout; | |
1015 | ||
2fa72c8f AC |
1016 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
1017 | || (level >= console_loglevel && !ignore_loglevel)) { | |
bfe8df3d | 1018 | return; |
2fa72c8f | 1019 | } |
bfe8df3d | 1020 | |
3a3b6ed2 | 1021 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
1022 | |
1023 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
1024 | while (k) { | |
1025 | k--; | |
1026 | cpu_relax(); | |
1027 | /* | |
1028 | * use (volatile) jiffies to prevent | |
1029 | * compiler reduction; loop termination via jiffies | |
1030 | * is secondary and may or may not happen. | |
1031 | */ | |
1032 | if (time_after(jiffies, timeout)) | |
1033 | break; | |
1034 | touch_nmi_watchdog(); | |
1035 | } | |
1036 | } | |
1037 | #else | |
2fa72c8f | 1038 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
1039 | { |
1040 | } | |
1041 | #endif | |
1042 | ||
e99aa461 | 1043 | static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); |
7ff9554b KS |
1044 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
1045 | ||
084681d1 KS |
1046 | static size_t print_time(u64 ts, char *buf) |
1047 | { | |
1048 | unsigned long rem_nsec; | |
1049 | ||
1050 | if (!printk_time) | |
1051 | return 0; | |
1052 | ||
35dac27c RD |
1053 | rem_nsec = do_div(ts, 1000000000); |
1054 | ||
084681d1 | 1055 | if (!buf) |
35dac27c | 1056 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 1057 | |
084681d1 KS |
1058 | return sprintf(buf, "[%5lu.%06lu] ", |
1059 | (unsigned long)ts, rem_nsec / 1000); | |
1060 | } | |
1061 | ||
62e32ac3 | 1062 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 1063 | { |
3ce9a7c0 | 1064 | size_t len = 0; |
43a73a50 | 1065 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 1066 | |
3ce9a7c0 KS |
1067 | if (syslog) { |
1068 | if (buf) { | |
43a73a50 | 1069 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
1070 | } else { |
1071 | len += 3; | |
43a73a50 KS |
1072 | if (prefix > 999) |
1073 | len += 3; | |
1074 | else if (prefix > 99) | |
1075 | len += 2; | |
1076 | else if (prefix > 9) | |
3ce9a7c0 KS |
1077 | len++; |
1078 | } | |
1079 | } | |
649e6ee3 | 1080 | |
084681d1 | 1081 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 1082 | return len; |
649e6ee3 KS |
1083 | } |
1084 | ||
62e32ac3 | 1085 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1086 | bool syslog, char *buf, size_t size) |
7ff9554b | 1087 | { |
3ce9a7c0 KS |
1088 | const char *text = log_text(msg); |
1089 | size_t text_size = msg->text_len; | |
5becfb1d KS |
1090 | bool prefix = true; |
1091 | bool newline = true; | |
3ce9a7c0 KS |
1092 | size_t len = 0; |
1093 | ||
5becfb1d KS |
1094 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
1095 | prefix = false; | |
1096 | ||
1097 | if (msg->flags & LOG_CONT) { | |
1098 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
1099 | prefix = false; | |
1100 | ||
1101 | if (!(msg->flags & LOG_NEWLINE)) | |
1102 | newline = false; | |
1103 | } | |
1104 | ||
3ce9a7c0 KS |
1105 | do { |
1106 | const char *next = memchr(text, '\n', text_size); | |
1107 | size_t text_len; | |
1108 | ||
1109 | if (next) { | |
1110 | text_len = next - text; | |
1111 | next++; | |
1112 | text_size -= next - text; | |
1113 | } else { | |
1114 | text_len = text_size; | |
1115 | } | |
7ff9554b | 1116 | |
3ce9a7c0 KS |
1117 | if (buf) { |
1118 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1119 | text_len + 1 >= size - len) |
3ce9a7c0 | 1120 | break; |
7ff9554b | 1121 | |
5becfb1d KS |
1122 | if (prefix) |
1123 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
1124 | memcpy(buf + len, text, text_len); |
1125 | len += text_len; | |
5becfb1d KS |
1126 | if (next || newline) |
1127 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
1128 | } else { |
1129 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
1130 | if (prefix) |
1131 | len += print_prefix(msg, syslog, NULL); | |
1132 | len += text_len; | |
1133 | if (next || newline) | |
1134 | len++; | |
3ce9a7c0 | 1135 | } |
7ff9554b | 1136 | |
5becfb1d | 1137 | prefix = true; |
3ce9a7c0 KS |
1138 | text = next; |
1139 | } while (text); | |
7ff9554b | 1140 | |
7ff9554b KS |
1141 | return len; |
1142 | } | |
1143 | ||
1144 | static int syslog_print(char __user *buf, int size) | |
1145 | { | |
1146 | char *text; | |
62e32ac3 | 1147 | struct printk_log *msg; |
116e90b2 | 1148 | int len = 0; |
7ff9554b | 1149 | |
70498253 | 1150 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1151 | if (!text) |
1152 | return -ENOMEM; | |
1153 | ||
116e90b2 JB |
1154 | while (size > 0) { |
1155 | size_t n; | |
eb02dac9 | 1156 | size_t skip; |
116e90b2 JB |
1157 | |
1158 | raw_spin_lock_irq(&logbuf_lock); | |
1159 | if (syslog_seq < log_first_seq) { | |
1160 | /* messages are gone, move to first one */ | |
1161 | syslog_seq = log_first_seq; | |
1162 | syslog_idx = log_first_idx; | |
5becfb1d | 1163 | syslog_prev = 0; |
eb02dac9 | 1164 | syslog_partial = 0; |
116e90b2 JB |
1165 | } |
1166 | if (syslog_seq == log_next_seq) { | |
1167 | raw_spin_unlock_irq(&logbuf_lock); | |
1168 | break; | |
1169 | } | |
eb02dac9 KS |
1170 | |
1171 | skip = syslog_partial; | |
116e90b2 | 1172 | msg = log_from_idx(syslog_idx); |
70498253 KS |
1173 | n = msg_print_text(msg, syslog_prev, true, text, |
1174 | LOG_LINE_MAX + PREFIX_MAX); | |
eb02dac9 KS |
1175 | if (n - syslog_partial <= size) { |
1176 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1177 | syslog_idx = log_next(syslog_idx); |
1178 | syslog_seq++; | |
5becfb1d | 1179 | syslog_prev = msg->flags; |
eb02dac9 KS |
1180 | n -= syslog_partial; |
1181 | syslog_partial = 0; | |
1182 | } else if (!len){ | |
1183 | /* partial read(), remember position */ | |
1184 | n = size; | |
1185 | syslog_partial += n; | |
116e90b2 JB |
1186 | } else |
1187 | n = 0; | |
1188 | raw_spin_unlock_irq(&logbuf_lock); | |
1189 | ||
1190 | if (!n) | |
1191 | break; | |
1192 | ||
eb02dac9 | 1193 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1194 | if (!len) |
1195 | len = -EFAULT; | |
1196 | break; | |
1197 | } | |
eb02dac9 KS |
1198 | |
1199 | len += n; | |
1200 | size -= n; | |
1201 | buf += n; | |
7ff9554b | 1202 | } |
7ff9554b KS |
1203 | |
1204 | kfree(text); | |
1205 | return len; | |
1206 | } | |
1207 | ||
1208 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1209 | { | |
1210 | char *text; | |
1211 | int len = 0; | |
1212 | ||
70498253 | 1213 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1214 | if (!text) |
1215 | return -ENOMEM; | |
1216 | ||
1217 | raw_spin_lock_irq(&logbuf_lock); | |
1218 | if (buf) { | |
1219 | u64 next_seq; | |
1220 | u64 seq; | |
1221 | u32 idx; | |
5becfb1d | 1222 | enum log_flags prev; |
7ff9554b | 1223 | |
7ff9554b KS |
1224 | /* |
1225 | * Find first record that fits, including all following records, | |
1226 | * into the user-provided buffer for this dump. | |
e2ae715d | 1227 | */ |
7ff9554b KS |
1228 | seq = clear_seq; |
1229 | idx = clear_idx; | |
5becfb1d | 1230 | prev = 0; |
7ff9554b | 1231 | while (seq < log_next_seq) { |
62e32ac3 | 1232 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1233 | |
5becfb1d | 1234 | len += msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1235 | prev = msg->flags; |
7ff9554b KS |
1236 | idx = log_next(idx); |
1237 | seq++; | |
1238 | } | |
e2ae715d KS |
1239 | |
1240 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1241 | seq = clear_seq; |
1242 | idx = clear_idx; | |
5becfb1d | 1243 | prev = 0; |
7ff9554b | 1244 | while (len > size && seq < log_next_seq) { |
62e32ac3 | 1245 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1246 | |
5becfb1d | 1247 | len -= msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1248 | prev = msg->flags; |
7ff9554b KS |
1249 | idx = log_next(idx); |
1250 | seq++; | |
1251 | } | |
1252 | ||
e2ae715d | 1253 | /* last message fitting into this dump */ |
7ff9554b KS |
1254 | next_seq = log_next_seq; |
1255 | ||
1256 | len = 0; | |
1257 | while (len >= 0 && seq < next_seq) { | |
62e32ac3 | 1258 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1259 | int textlen; |
1260 | ||
70498253 KS |
1261 | textlen = msg_print_text(msg, prev, true, text, |
1262 | LOG_LINE_MAX + PREFIX_MAX); | |
7ff9554b KS |
1263 | if (textlen < 0) { |
1264 | len = textlen; | |
1265 | break; | |
1266 | } | |
1267 | idx = log_next(idx); | |
1268 | seq++; | |
5becfb1d | 1269 | prev = msg->flags; |
7ff9554b KS |
1270 | |
1271 | raw_spin_unlock_irq(&logbuf_lock); | |
1272 | if (copy_to_user(buf + len, text, textlen)) | |
1273 | len = -EFAULT; | |
1274 | else | |
1275 | len += textlen; | |
1276 | raw_spin_lock_irq(&logbuf_lock); | |
1277 | ||
1278 | if (seq < log_first_seq) { | |
1279 | /* messages are gone, move to next one */ | |
1280 | seq = log_first_seq; | |
1281 | idx = log_first_idx; | |
5becfb1d | 1282 | prev = 0; |
7ff9554b KS |
1283 | } |
1284 | } | |
1285 | } | |
1286 | ||
1287 | if (clear) { | |
1288 | clear_seq = log_next_seq; | |
1289 | clear_idx = log_next_idx; | |
1290 | } | |
1291 | raw_spin_unlock_irq(&logbuf_lock); | |
1292 | ||
1293 | kfree(text); | |
1294 | return len; | |
1295 | } | |
1296 | ||
3ea4331c | 1297 | int do_syslog(int type, char __user *buf, int len, int source) |
1da177e4 | 1298 | { |
7ff9554b | 1299 | bool clear = false; |
a39d4a85 | 1300 | static int saved_console_loglevel = LOGLEVEL_DEFAULT; |
ee24aebf | 1301 | int error; |
1da177e4 | 1302 | |
3ea4331c | 1303 | error = check_syslog_permissions(type, source); |
ee24aebf LT |
1304 | if (error) |
1305 | goto out; | |
12b3052c | 1306 | |
1da177e4 | 1307 | switch (type) { |
d78ca3cd | 1308 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1309 | break; |
d78ca3cd | 1310 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1311 | break; |
d78ca3cd | 1312 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1313 | error = -EINVAL; |
1314 | if (!buf || len < 0) | |
1315 | goto out; | |
1316 | error = 0; | |
1317 | if (!len) | |
1318 | goto out; | |
1319 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1320 | error = -EFAULT; | |
1321 | goto out; | |
1322 | } | |
40dc5651 | 1323 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1324 | syslog_seq != log_next_seq); |
cb424ffe | 1325 | if (error) |
1da177e4 | 1326 | goto out; |
7ff9554b | 1327 | error = syslog_print(buf, len); |
1da177e4 | 1328 | break; |
d78ca3cd KC |
1329 | /* Read/clear last kernel messages */ |
1330 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1331 | clear = true; |
1da177e4 | 1332 | /* FALL THRU */ |
d78ca3cd KC |
1333 | /* Read last kernel messages */ |
1334 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1335 | error = -EINVAL; |
1336 | if (!buf || len < 0) | |
1337 | goto out; | |
1338 | error = 0; | |
1339 | if (!len) | |
1340 | goto out; | |
1341 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1342 | error = -EFAULT; | |
1343 | goto out; | |
1344 | } | |
7ff9554b | 1345 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1346 | break; |
d78ca3cd KC |
1347 | /* Clear ring buffer */ |
1348 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1349 | syslog_print_all(NULL, 0, true); |
4661e356 | 1350 | break; |
d78ca3cd KC |
1351 | /* Disable logging to console */ |
1352 | case SYSLOG_ACTION_CONSOLE_OFF: | |
a39d4a85 | 1353 | if (saved_console_loglevel == LOGLEVEL_DEFAULT) |
1aaad49e | 1354 | saved_console_loglevel = console_loglevel; |
1da177e4 LT |
1355 | console_loglevel = minimum_console_loglevel; |
1356 | break; | |
d78ca3cd KC |
1357 | /* Enable logging to console */ |
1358 | case SYSLOG_ACTION_CONSOLE_ON: | |
a39d4a85 | 1359 | if (saved_console_loglevel != LOGLEVEL_DEFAULT) { |
1aaad49e | 1360 | console_loglevel = saved_console_loglevel; |
a39d4a85 | 1361 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1aaad49e | 1362 | } |
1da177e4 | 1363 | break; |
d78ca3cd KC |
1364 | /* Set level of messages printed to console */ |
1365 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1366 | error = -EINVAL; |
1367 | if (len < 1 || len > 8) | |
1368 | goto out; | |
1369 | if (len < minimum_console_loglevel) | |
1370 | len = minimum_console_loglevel; | |
1371 | console_loglevel = len; | |
1aaad49e | 1372 | /* Implicitly re-enable logging to console */ |
a39d4a85 | 1373 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1da177e4 LT |
1374 | error = 0; |
1375 | break; | |
d78ca3cd KC |
1376 | /* Number of chars in the log buffer */ |
1377 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1378 | raw_spin_lock_irq(&logbuf_lock); |
1379 | if (syslog_seq < log_first_seq) { | |
1380 | /* messages are gone, move to first one */ | |
1381 | syslog_seq = log_first_seq; | |
1382 | syslog_idx = log_first_idx; | |
5becfb1d | 1383 | syslog_prev = 0; |
eb02dac9 | 1384 | syslog_partial = 0; |
7ff9554b | 1385 | } |
3ea4331c | 1386 | if (source == SYSLOG_FROM_PROC) { |
7ff9554b KS |
1387 | /* |
1388 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1389 | * for pending data, not the size; return the count of | |
1390 | * records, not the length. | |
1391 | */ | |
e97e1267 | 1392 | error = log_next_seq - syslog_seq; |
7ff9554b | 1393 | } else { |
5becfb1d KS |
1394 | u64 seq = syslog_seq; |
1395 | u32 idx = syslog_idx; | |
1396 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1397 | |
1398 | error = 0; | |
7ff9554b | 1399 | while (seq < log_next_seq) { |
62e32ac3 | 1400 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1401 | |
5becfb1d | 1402 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1403 | idx = log_next(idx); |
1404 | seq++; | |
5becfb1d | 1405 | prev = msg->flags; |
7ff9554b | 1406 | } |
eb02dac9 | 1407 | error -= syslog_partial; |
7ff9554b KS |
1408 | } |
1409 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1410 | break; |
d78ca3cd KC |
1411 | /* Size of the log buffer */ |
1412 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1413 | error = log_buf_len; |
1414 | break; | |
1415 | default: | |
1416 | error = -EINVAL; | |
1417 | break; | |
1418 | } | |
1419 | out: | |
1420 | return error; | |
1421 | } | |
1422 | ||
1e7bfb21 | 1423 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1424 | { |
637241a9 | 1425 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1426 | } |
1427 | ||
1da177e4 LT |
1428 | /* |
1429 | * Call the console drivers, asking them to write out | |
1430 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1431 | * The console_lock must be held. |
1da177e4 | 1432 | */ |
6fe29354 TH |
1433 | static void call_console_drivers(int level, |
1434 | const char *ext_text, size_t ext_len, | |
1435 | const char *text, size_t len) | |
1da177e4 | 1436 | { |
7ff9554b | 1437 | struct console *con; |
1da177e4 | 1438 | |
07c65f4d | 1439 | trace_console(text, len); |
7ff9554b KS |
1440 | |
1441 | if (level >= console_loglevel && !ignore_loglevel) | |
1442 | return; | |
1443 | if (!console_drivers) | |
1444 | return; | |
1445 | ||
1446 | for_each_console(con) { | |
1447 | if (exclusive_console && con != exclusive_console) | |
1448 | continue; | |
1449 | if (!(con->flags & CON_ENABLED)) | |
1450 | continue; | |
1451 | if (!con->write) | |
1452 | continue; | |
1453 | if (!cpu_online(smp_processor_id()) && | |
1454 | !(con->flags & CON_ANYTIME)) | |
1455 | continue; | |
6fe29354 TH |
1456 | if (con->flags & CON_EXTENDED) |
1457 | con->write(con, ext_text, ext_len); | |
1458 | else | |
1459 | con->write(con, text, len); | |
7ff9554b | 1460 | } |
1da177e4 LT |
1461 | } |
1462 | ||
1463 | /* | |
205bd3d2 JP |
1464 | * Zap console related locks when oopsing. |
1465 | * To leave time for slow consoles to print a full oops, | |
1466 | * only zap at most once every 30 seconds. | |
1da177e4 LT |
1467 | */ |
1468 | static void zap_locks(void) | |
1469 | { | |
1470 | static unsigned long oops_timestamp; | |
1471 | ||
1472 | if (time_after_eq(jiffies, oops_timestamp) && | |
205bd3d2 | 1473 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1474 | return; |
1475 | ||
1476 | oops_timestamp = jiffies; | |
1477 | ||
94d24fc4 | 1478 | debug_locks_off(); |
1da177e4 | 1479 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1480 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1481 | /* And make sure that we print immediately */ |
5b8c4f23 | 1482 | sema_init(&console_sem, 1); |
1da177e4 LT |
1483 | } |
1484 | ||
af91322e DY |
1485 | int printk_delay_msec __read_mostly; |
1486 | ||
1487 | static inline void printk_delay(void) | |
1488 | { | |
1489 | if (unlikely(printk_delay_msec)) { | |
1490 | int m = printk_delay_msec; | |
1491 | ||
1492 | while (m--) { | |
1493 | mdelay(1); | |
1494 | touch_nmi_watchdog(); | |
1495 | } | |
1496 | } | |
1497 | } | |
1498 | ||
084681d1 KS |
1499 | /* |
1500 | * Continuation lines are buffered, and not committed to the record buffer | |
1501 | * until the line is complete, or a race forces it. The line fragments | |
1502 | * though, are printed immediately to the consoles to ensure everything has | |
1503 | * reached the console in case of a kernel crash. | |
1504 | */ | |
1505 | static struct cont { | |
1506 | char buf[LOG_LINE_MAX]; | |
1507 | size_t len; /* length == 0 means unused buffer */ | |
1508 | size_t cons; /* bytes written to console */ | |
1509 | struct task_struct *owner; /* task of first print*/ | |
1510 | u64 ts_nsec; /* time of first print */ | |
1511 | u8 level; /* log level of first message */ | |
0b90fec3 | 1512 | u8 facility; /* log facility of first message */ |
eab07260 | 1513 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1514 | bool flushed:1; /* buffer sealed and committed */ |
1515 | } cont; | |
1516 | ||
70498253 | 1517 | static void cont_flush(enum log_flags flags) |
084681d1 KS |
1518 | { |
1519 | if (cont.flushed) | |
1520 | return; | |
1521 | if (cont.len == 0) | |
1522 | return; | |
1523 | ||
eab07260 KS |
1524 | if (cont.cons) { |
1525 | /* | |
1526 | * If a fragment of this line was directly flushed to the | |
1527 | * console; wait for the console to pick up the rest of the | |
1528 | * line. LOG_NOCONS suppresses a duplicated output. | |
1529 | */ | |
1530 | log_store(cont.facility, cont.level, flags | LOG_NOCONS, | |
1531 | cont.ts_nsec, NULL, 0, cont.buf, cont.len); | |
1532 | cont.flags = flags; | |
1533 | cont.flushed = true; | |
1534 | } else { | |
1535 | /* | |
1536 | * If no fragment of this line ever reached the console, | |
1537 | * just submit it to the store and free the buffer. | |
1538 | */ | |
1539 | log_store(cont.facility, cont.level, flags, 0, | |
1540 | NULL, 0, cont.buf, cont.len); | |
1541 | cont.len = 0; | |
1542 | } | |
084681d1 KS |
1543 | } |
1544 | ||
1545 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1546 | { | |
1547 | if (cont.len && cont.flushed) | |
1548 | return false; | |
1549 | ||
6fe29354 TH |
1550 | /* |
1551 | * If ext consoles are present, flush and skip in-kernel | |
1552 | * continuation. See nr_ext_console_drivers definition. Also, if | |
1553 | * the line gets too long, split it up in separate records. | |
1554 | */ | |
1555 | if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) { | |
70498253 | 1556 | cont_flush(LOG_CONT); |
084681d1 KS |
1557 | return false; |
1558 | } | |
1559 | ||
1560 | if (!cont.len) { | |
1561 | cont.facility = facility; | |
1562 | cont.level = level; | |
1563 | cont.owner = current; | |
1564 | cont.ts_nsec = local_clock(); | |
eab07260 | 1565 | cont.flags = 0; |
084681d1 KS |
1566 | cont.cons = 0; |
1567 | cont.flushed = false; | |
1568 | } | |
1569 | ||
1570 | memcpy(cont.buf + cont.len, text, len); | |
1571 | cont.len += len; | |
eab07260 KS |
1572 | |
1573 | if (cont.len > (sizeof(cont.buf) * 80) / 100) | |
1574 | cont_flush(LOG_CONT); | |
1575 | ||
084681d1 KS |
1576 | return true; |
1577 | } | |
1578 | ||
1579 | static size_t cont_print_text(char *text, size_t size) | |
1580 | { | |
1581 | size_t textlen = 0; | |
1582 | size_t len; | |
1583 | ||
eab07260 | 1584 | if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
084681d1 KS |
1585 | textlen += print_time(cont.ts_nsec, text); |
1586 | size -= textlen; | |
1587 | } | |
1588 | ||
1589 | len = cont.len - cont.cons; | |
1590 | if (len > 0) { | |
1591 | if (len+1 > size) | |
1592 | len = size-1; | |
1593 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1594 | textlen += len; | |
1595 | cont.cons = cont.len; | |
1596 | } | |
1597 | ||
1598 | if (cont.flushed) { | |
eab07260 KS |
1599 | if (cont.flags & LOG_NEWLINE) |
1600 | text[textlen++] = '\n'; | |
084681d1 KS |
1601 | /* got everything, release buffer */ |
1602 | cont.len = 0; | |
1603 | } | |
1604 | return textlen; | |
1605 | } | |
1606 | ||
7ff9554b KS |
1607 | asmlinkage int vprintk_emit(int facility, int level, |
1608 | const char *dict, size_t dictlen, | |
1609 | const char *fmt, va_list args) | |
1da177e4 | 1610 | { |
06b031de | 1611 | static bool recursion_bug; |
7ff9554b KS |
1612 | static char textbuf[LOG_LINE_MAX]; |
1613 | char *text = textbuf; | |
458df9fd | 1614 | size_t text_len = 0; |
5becfb1d | 1615 | enum log_flags lflags = 0; |
ac60ad74 | 1616 | unsigned long flags; |
32a76006 | 1617 | int this_cpu; |
7ff9554b | 1618 | int printed_len = 0; |
458df9fd | 1619 | bool in_sched = false; |
608873ca | 1620 | /* cpu currently holding logbuf_lock in this function */ |
f099755d | 1621 | static unsigned int logbuf_cpu = UINT_MAX; |
608873ca | 1622 | |
a39d4a85 JP |
1623 | if (level == LOGLEVEL_SCHED) { |
1624 | level = LOGLEVEL_DEFAULT; | |
458df9fd SR |
1625 | in_sched = true; |
1626 | } | |
1da177e4 | 1627 | |
2fa72c8f | 1628 | boot_delay_msec(level); |
af91322e | 1629 | printk_delay(); |
bfe8df3d | 1630 | |
1a9a8aef | 1631 | local_irq_save(flags); |
32a76006 IM |
1632 | this_cpu = smp_processor_id(); |
1633 | ||
1634 | /* | |
1635 | * Ouch, printk recursed into itself! | |
1636 | */ | |
7ff9554b | 1637 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1638 | /* |
1639 | * If a crash is occurring during printk() on this CPU, | |
1640 | * then try to get the crash message out but make sure | |
1641 | * we can't deadlock. Otherwise just return to avoid the | |
1642 | * recursion and return - but flag the recursion so that | |
1643 | * it can be printed at the next appropriate moment: | |
1644 | */ | |
94d24fc4 | 1645 | if (!oops_in_progress && !lockdep_recursing(current)) { |
06b031de | 1646 | recursion_bug = true; |
5874af20 JK |
1647 | local_irq_restore(flags); |
1648 | return 0; | |
32a76006 IM |
1649 | } |
1650 | zap_locks(); | |
1651 | } | |
1652 | ||
a0f1ccfd | 1653 | lockdep_off(); |
a8199371 | 1654 | /* This stops the holder of console_sem just where we want him */ |
07354eb1 | 1655 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1656 | logbuf_cpu = this_cpu; |
1da177e4 | 1657 | |
000a7d66 | 1658 | if (unlikely(recursion_bug)) { |
7ff9554b KS |
1659 | static const char recursion_msg[] = |
1660 | "BUG: recent printk recursion!"; | |
1661 | ||
06b031de | 1662 | recursion_bug = false; |
7ff9554b | 1663 | /* emit KERN_CRIT message */ |
034633cc | 1664 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
000a7d66 PP |
1665 | NULL, 0, recursion_msg, |
1666 | strlen(recursion_msg)); | |
32a76006 | 1667 | } |
1da177e4 | 1668 | |
7ff9554b KS |
1669 | /* |
1670 | * The printf needs to come first; we need the syslog | |
1671 | * prefix which might be passed-in as a parameter. | |
1672 | */ | |
98e35f58 | 1673 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1674 | |
7ff9554b | 1675 | /* mark and strip a trailing newline */ |
c313af14 KS |
1676 | if (text_len && text[text_len-1] == '\n') { |
1677 | text_len--; | |
5becfb1d | 1678 | lflags |= LOG_NEWLINE; |
7ff9554b | 1679 | } |
9d90c8d9 | 1680 | |
088a52aa JP |
1681 | /* strip kernel syslog prefix and extract log level or control flags */ |
1682 | if (facility == 0) { | |
1683 | int kern_level = printk_get_level(text); | |
1684 | ||
1685 | if (kern_level) { | |
1686 | const char *end_of_header = printk_skip_level(text); | |
1687 | switch (kern_level) { | |
1688 | case '0' ... '7': | |
a39d4a85 | 1689 | if (level == LOGLEVEL_DEFAULT) |
088a52aa | 1690 | level = kern_level - '0'; |
a39d4a85 | 1691 | /* fallthrough */ |
088a52aa JP |
1692 | case 'd': /* KERN_DEFAULT */ |
1693 | lflags |= LOG_PREFIX; | |
088a52aa | 1694 | } |
e8c42d36 PM |
1695 | /* |
1696 | * No need to check length here because vscnprintf | |
1697 | * put '\0' at the end of the string. Only valid and | |
1698 | * newly printed level is detected. | |
1699 | */ | |
088a52aa JP |
1700 | text_len -= end_of_header - text; |
1701 | text = (char *)end_of_header; | |
5fd29d6c LT |
1702 | } |
1703 | } | |
1704 | ||
a39d4a85 | 1705 | if (level == LOGLEVEL_DEFAULT) |
c313af14 | 1706 | level = default_message_loglevel; |
9d90c8d9 | 1707 | |
5becfb1d KS |
1708 | if (dict) |
1709 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1710 | |
5becfb1d | 1711 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1712 | /* |
1713 | * Flush the conflicting buffer. An earlier newline was missing, | |
1714 | * or another task also prints continuation lines. | |
1715 | */ | |
5becfb1d | 1716 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
eab07260 | 1717 | cont_flush(LOG_NEWLINE); |
c313af14 | 1718 | |
084681d1 | 1719 | /* buffer line if possible, otherwise store it right away */ |
034633cc PM |
1720 | if (cont_add(facility, level, text, text_len)) |
1721 | printed_len += text_len; | |
1722 | else | |
1723 | printed_len += log_store(facility, level, | |
1724 | lflags | LOG_CONT, 0, | |
1725 | dict, dictlen, text, text_len); | |
5c5d5ca5 | 1726 | } else { |
084681d1 | 1727 | bool stored = false; |
c313af14 | 1728 | |
084681d1 | 1729 | /* |
d3620822 SR |
1730 | * If an earlier newline was missing and it was the same task, |
1731 | * either merge it with the current buffer and flush, or if | |
1732 | * there was a race with interrupts (prefix == true) then just | |
1733 | * flush it out and store this line separately. | |
1d3fa370 AK |
1734 | * If the preceding printk was from a different task and missed |
1735 | * a newline, flush and append the newline. | |
084681d1 | 1736 | */ |
1d3fa370 AK |
1737 | if (cont.len) { |
1738 | if (cont.owner == current && !(lflags & LOG_PREFIX)) | |
1739 | stored = cont_add(facility, level, text, | |
1740 | text_len); | |
eab07260 | 1741 | cont_flush(LOG_NEWLINE); |
c313af14 | 1742 | } |
084681d1 | 1743 | |
034633cc PM |
1744 | if (stored) |
1745 | printed_len += text_len; | |
1746 | else | |
1747 | printed_len += log_store(facility, level, lflags, 0, | |
1748 | dict, dictlen, text, text_len); | |
1da177e4 LT |
1749 | } |
1750 | ||
608873ca JK |
1751 | logbuf_cpu = UINT_MAX; |
1752 | raw_spin_unlock(&logbuf_lock); | |
5874af20 JK |
1753 | lockdep_on(); |
1754 | local_irq_restore(flags); | |
939f04be | 1755 | |
458df9fd | 1756 | /* If called from the scheduler, we can not call up(). */ |
d18bbc21 | 1757 | if (!in_sched) { |
5874af20 | 1758 | lockdep_off(); |
d18bbc21 AM |
1759 | /* |
1760 | * Try to acquire and then immediately release the console | |
1761 | * semaphore. The release will print out buffers and wake up | |
1762 | * /dev/kmsg and syslog() users. | |
1763 | */ | |
a8199371 | 1764 | if (console_trylock()) |
d18bbc21 | 1765 | console_unlock(); |
5874af20 | 1766 | lockdep_on(); |
d18bbc21 | 1767 | } |
76a8ad29 | 1768 | |
1da177e4 LT |
1769 | return printed_len; |
1770 | } | |
7ff9554b KS |
1771 | EXPORT_SYMBOL(vprintk_emit); |
1772 | ||
1773 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1774 | { | |
a39d4a85 | 1775 | return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
7ff9554b | 1776 | } |
1da177e4 LT |
1777 | EXPORT_SYMBOL(vprintk); |
1778 | ||
7ff9554b KS |
1779 | asmlinkage int printk_emit(int facility, int level, |
1780 | const char *dict, size_t dictlen, | |
1781 | const char *fmt, ...) | |
1782 | { | |
1783 | va_list args; | |
1784 | int r; | |
1785 | ||
1786 | va_start(args, fmt); | |
1787 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1788 | va_end(args); | |
1789 | ||
1790 | return r; | |
1791 | } | |
1792 | EXPORT_SYMBOL(printk_emit); | |
1793 | ||
afdc34a3 SRRH |
1794 | int vprintk_default(const char *fmt, va_list args) |
1795 | { | |
1796 | int r; | |
1797 | ||
1798 | #ifdef CONFIG_KGDB_KDB | |
1799 | if (unlikely(kdb_trap_printk)) { | |
f7d4ca8b | 1800 | r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); |
afdc34a3 SRRH |
1801 | return r; |
1802 | } | |
1803 | #endif | |
350e4f49 | 1804 | r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
afdc34a3 SRRH |
1805 | |
1806 | return r; | |
1807 | } | |
1808 | EXPORT_SYMBOL_GPL(vprintk_default); | |
1809 | ||
1810 | /* | |
1811 | * This allows printk to be diverted to another function per cpu. | |
1812 | * This is useful for calling printk functions from within NMI | |
1813 | * without worrying about race conditions that can lock up the | |
1814 | * box. | |
1815 | */ | |
1816 | DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default; | |
1817 | ||
7ff9554b KS |
1818 | /** |
1819 | * printk - print a kernel message | |
1820 | * @fmt: format string | |
1821 | * | |
1822 | * This is printk(). It can be called from any context. We want it to work. | |
1823 | * | |
1824 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1825 | * output and call the console drivers. If we fail to get the semaphore, we | |
1826 | * place the output into the log buffer and return. The current holder of | |
1827 | * the console_sem will notice the new output in console_unlock(); and will | |
1828 | * send it to the consoles before releasing the lock. | |
1829 | * | |
1830 | * One effect of this deferred printing is that code which calls printk() and | |
1831 | * then changes console_loglevel may break. This is because console_loglevel | |
1832 | * is inspected when the actual printing occurs. | |
1833 | * | |
1834 | * See also: | |
1835 | * printf(3) | |
1836 | * | |
1837 | * See the vsnprintf() documentation for format string extensions over C99. | |
1838 | */ | |
722a9f92 | 1839 | asmlinkage __visible int printk(const char *fmt, ...) |
7ff9554b | 1840 | { |
afdc34a3 | 1841 | printk_func_t vprintk_func; |
7ff9554b KS |
1842 | va_list args; |
1843 | int r; | |
1844 | ||
7ff9554b | 1845 | va_start(args, fmt); |
1fb8915b SRRH |
1846 | |
1847 | /* | |
1848 | * If a caller overrides the per_cpu printk_func, then it needs | |
1849 | * to disable preemption when calling printk(). Otherwise | |
1850 | * the printk_func should be set to the default. No need to | |
1851 | * disable preemption here. | |
1852 | */ | |
afdc34a3 SRRH |
1853 | vprintk_func = this_cpu_read(printk_func); |
1854 | r = vprintk_func(fmt, args); | |
1fb8915b | 1855 | |
7ff9554b KS |
1856 | va_end(args); |
1857 | ||
1858 | return r; | |
1859 | } | |
1860 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1861 | |
96efedf1 | 1862 | #else /* CONFIG_PRINTK */ |
d59745ce | 1863 | |
70498253 KS |
1864 | #define LOG_LINE_MAX 0 |
1865 | #define PREFIX_MAX 0 | |
249771b8 | 1866 | |
96efedf1 KS |
1867 | static u64 syslog_seq; |
1868 | static u32 syslog_idx; | |
eab07260 KS |
1869 | static u64 console_seq; |
1870 | static u32 console_idx; | |
96efedf1 KS |
1871 | static enum log_flags syslog_prev; |
1872 | static u64 log_first_seq; | |
1873 | static u32 log_first_idx; | |
1874 | static u64 log_next_seq; | |
eab07260 | 1875 | static enum log_flags console_prev; |
084681d1 KS |
1876 | static struct cont { |
1877 | size_t len; | |
1878 | size_t cons; | |
1879 | u8 level; | |
1880 | bool flushed:1; | |
1881 | } cont; | |
6fe29354 TH |
1882 | static char *log_text(const struct printk_log *msg) { return NULL; } |
1883 | static char *log_dict(const struct printk_log *msg) { return NULL; } | |
62e32ac3 | 1884 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1885 | static u32 log_next(u32 idx) { return 0; } |
6fe29354 TH |
1886 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
1887 | struct printk_log *msg, u64 seq, | |
1888 | enum log_flags prev_flags) { return 0; } | |
1889 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
1890 | char *dict, size_t dict_len, | |
1891 | char *text, size_t text_len) { return 0; } | |
1892 | static void call_console_drivers(int level, | |
1893 | const char *ext_text, size_t ext_len, | |
1894 | const char *text, size_t len) {} | |
62e32ac3 | 1895 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1896 | bool syslog, char *buf, size_t size) { return 0; } |
084681d1 | 1897 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1898 | |
04b74b27 SRRH |
1899 | /* Still needs to be defined for users */ |
1900 | DEFINE_PER_CPU(printk_func_t, printk_func); | |
1901 | ||
7f3a781d | 1902 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1903 | |
d0380e6c TG |
1904 | #ifdef CONFIG_EARLY_PRINTK |
1905 | struct console *early_console; | |
1906 | ||
722a9f92 | 1907 | asmlinkage __visible void early_printk(const char *fmt, ...) |
d0380e6c TG |
1908 | { |
1909 | va_list ap; | |
1dc6244b JP |
1910 | char buf[512]; |
1911 | int n; | |
1912 | ||
1913 | if (!early_console) | |
1914 | return; | |
d0380e6c TG |
1915 | |
1916 | va_start(ap, fmt); | |
1dc6244b | 1917 | n = vscnprintf(buf, sizeof(buf), fmt, ap); |
d0380e6c | 1918 | va_end(ap); |
1dc6244b JP |
1919 | |
1920 | early_console->write(early_console, buf, n); | |
d0380e6c TG |
1921 | } |
1922 | #endif | |
1923 | ||
f7511d5f ST |
1924 | static int __add_preferred_console(char *name, int idx, char *options, |
1925 | char *brl_options) | |
1926 | { | |
1927 | struct console_cmdline *c; | |
1928 | int i; | |
1929 | ||
1930 | /* | |
1931 | * See if this tty is not yet registered, and | |
1932 | * if we have a slot free. | |
1933 | */ | |
23475408 JP |
1934 | for (i = 0, c = console_cmdline; |
1935 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1936 | i++, c++) { | |
1937 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1938 | if (!brl_options) | |
1939 | selected_console = i; | |
1940 | return 0; | |
f7511d5f | 1941 | } |
23475408 | 1942 | } |
f7511d5f ST |
1943 | if (i == MAX_CMDLINECONSOLES) |
1944 | return -E2BIG; | |
1945 | if (!brl_options) | |
1946 | selected_console = i; | |
f7511d5f ST |
1947 | strlcpy(c->name, name, sizeof(c->name)); |
1948 | c->options = options; | |
bbeddf52 JP |
1949 | braille_set_options(c, brl_options); |
1950 | ||
f7511d5f ST |
1951 | c->index = idx; |
1952 | return 0; | |
1953 | } | |
2ea1c539 | 1954 | /* |
0b90fec3 AE |
1955 | * Set up a console. Called via do_early_param() in init/main.c |
1956 | * for each "console=" parameter in the boot command line. | |
2ea1c539 JB |
1957 | */ |
1958 | static int __init console_setup(char *str) | |
1959 | { | |
0b90fec3 | 1960 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */ |
f7511d5f | 1961 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1962 | int idx; |
1963 | ||
bbeddf52 JP |
1964 | if (_braille_console_setup(&str, &brl_options)) |
1965 | return 1; | |
f7511d5f | 1966 | |
2ea1c539 JB |
1967 | /* |
1968 | * Decode str into name, index, options. | |
1969 | */ | |
1970 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1971 | strcpy(buf, "ttyS"); |
1972 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1973 | } else { |
eaa944af | 1974 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1975 | } |
eaa944af | 1976 | buf[sizeof(buf) - 1] = 0; |
249771b8 AE |
1977 | options = strchr(str, ','); |
1978 | if (options) | |
2ea1c539 JB |
1979 | *(options++) = 0; |
1980 | #ifdef __sparc__ | |
1981 | if (!strcmp(str, "ttya")) | |
eaa944af | 1982 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1983 | if (!strcmp(str, "ttyb")) |
eaa944af | 1984 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1985 | #endif |
eaa944af | 1986 | for (s = buf; *s; s++) |
249771b8 | 1987 | if (isdigit(*s) || *s == ',') |
2ea1c539 JB |
1988 | break; |
1989 | idx = simple_strtoul(s, NULL, 10); | |
1990 | *s = 0; | |
1991 | ||
f7511d5f | 1992 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1993 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1994 | return 1; |
1995 | } | |
1996 | __setup("console=", console_setup); | |
1997 | ||
3c0547ba MM |
1998 | /** |
1999 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
2000 | * @name: device name |
2001 | * @idx: device index | |
2002 | * @options: options for this console | |
3c0547ba MM |
2003 | * |
2004 | * The last preferred console added will be used for kernel messages | |
2005 | * and stdin/out/err for init. Normally this is used by console_setup | |
2006 | * above to handle user-supplied console arguments; however it can also | |
2007 | * be used by arch-specific code either to override the user or more | |
2008 | * commonly to provide a default console (ie from PROM variables) when | |
2009 | * the user has not supplied one. | |
2010 | */ | |
fb445ee5 | 2011 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 2012 | { |
f7511d5f | 2013 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
2014 | } |
2015 | ||
d25d9fec | 2016 | bool console_suspend_enabled = true; |
8f4ce8c3 AS |
2017 | EXPORT_SYMBOL(console_suspend_enabled); |
2018 | ||
2019 | static int __init console_suspend_disable(char *str) | |
2020 | { | |
d25d9fec | 2021 | console_suspend_enabled = false; |
8f4ce8c3 AS |
2022 | return 1; |
2023 | } | |
2024 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
2025 | module_param_named(console_suspend, console_suspend_enabled, |
2026 | bool, S_IRUGO | S_IWUSR); | |
2027 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
2028 | " and hibernate operations"); | |
8f4ce8c3 | 2029 | |
557240b4 LT |
2030 | /** |
2031 | * suspend_console - suspend the console subsystem | |
2032 | * | |
2033 | * This disables printk() while we go into suspend states | |
2034 | */ | |
2035 | void suspend_console(void) | |
2036 | { | |
8f4ce8c3 AS |
2037 | if (!console_suspend_enabled) |
2038 | return; | |
0d63081d | 2039 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 2040 | console_lock(); |
557240b4 | 2041 | console_suspended = 1; |
bd8d7cf5 | 2042 | up_console_sem(); |
557240b4 LT |
2043 | } |
2044 | ||
2045 | void resume_console(void) | |
2046 | { | |
8f4ce8c3 AS |
2047 | if (!console_suspend_enabled) |
2048 | return; | |
bd8d7cf5 | 2049 | down_console_sem(); |
557240b4 | 2050 | console_suspended = 0; |
ac751efa | 2051 | console_unlock(); |
557240b4 LT |
2052 | } |
2053 | ||
034260d6 KC |
2054 | /** |
2055 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
2056 | * @self: notifier struct | |
2057 | * @action: CPU hotplug event | |
2058 | * @hcpu: unused | |
2059 | * | |
2060 | * If printk() is called from a CPU that is not online yet, the messages | |
2061 | * will be spooled but will not show up on the console. This function is | |
2062 | * called when a new CPU comes online (or fails to come up), and ensures | |
2063 | * that any such output gets printed. | |
2064 | */ | |
0db0628d | 2065 | static int console_cpu_notify(struct notifier_block *self, |
034260d6 KC |
2066 | unsigned long action, void *hcpu) |
2067 | { | |
2068 | switch (action) { | |
2069 | case CPU_ONLINE: | |
2070 | case CPU_DEAD: | |
034260d6 KC |
2071 | case CPU_DOWN_FAILED: |
2072 | case CPU_UP_CANCELED: | |
ac751efa TH |
2073 | console_lock(); |
2074 | console_unlock(); | |
034260d6 KC |
2075 | } |
2076 | return NOTIFY_OK; | |
2077 | } | |
2078 | ||
1da177e4 | 2079 | /** |
ac751efa | 2080 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2081 | * |
ac751efa | 2082 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2083 | * exclusive access to the console system and the console_drivers list. |
2084 | * | |
2085 | * Can sleep, returns nothing. | |
2086 | */ | |
ac751efa | 2087 | void console_lock(void) |
1da177e4 | 2088 | { |
6b898c07 DV |
2089 | might_sleep(); |
2090 | ||
bd8d7cf5 | 2091 | down_console_sem(); |
403f3075 AH |
2092 | if (console_suspended) |
2093 | return; | |
1da177e4 LT |
2094 | console_locked = 1; |
2095 | console_may_schedule = 1; | |
2096 | } | |
ac751efa | 2097 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2098 | |
ac751efa TH |
2099 | /** |
2100 | * console_trylock - try to lock the console system for exclusive use. | |
2101 | * | |
0b90fec3 AE |
2102 | * Try to acquire a lock which guarantees that the caller has exclusive |
2103 | * access to the console system and the console_drivers list. | |
ac751efa TH |
2104 | * |
2105 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2106 | */ | |
2107 | int console_trylock(void) | |
1da177e4 | 2108 | { |
bd8d7cf5 | 2109 | if (down_trylock_console_sem()) |
ac751efa | 2110 | return 0; |
403f3075 | 2111 | if (console_suspended) { |
bd8d7cf5 | 2112 | up_console_sem(); |
ac751efa | 2113 | return 0; |
403f3075 | 2114 | } |
1da177e4 | 2115 | console_locked = 1; |
6b97a20d SS |
2116 | /* |
2117 | * When PREEMPT_COUNT disabled we can't reliably detect if it's | |
2118 | * safe to schedule (e.g. calling printk while holding a spin_lock), | |
2119 | * because preempt_disable()/preempt_enable() are just barriers there | |
2120 | * and preempt_count() is always 0. | |
2121 | * | |
2122 | * RCU read sections have a separate preemption counter when | |
2123 | * PREEMPT_RCU enabled thus we must take extra care and check | |
2124 | * rcu_preempt_depth(), otherwise RCU read sections modify | |
2125 | * preempt_count(). | |
2126 | */ | |
2127 | console_may_schedule = !oops_in_progress && | |
2128 | preemptible() && | |
2129 | !rcu_preempt_depth(); | |
ac751efa | 2130 | return 1; |
1da177e4 | 2131 | } |
ac751efa | 2132 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2133 | |
2134 | int is_console_locked(void) | |
2135 | { | |
2136 | return console_locked; | |
2137 | } | |
1da177e4 | 2138 | |
a8199371 SS |
2139 | /* |
2140 | * Check if we have any console that is capable of printing while cpu is | |
2141 | * booting or shutting down. Requires console_sem. | |
2142 | */ | |
2143 | static int have_callable_console(void) | |
2144 | { | |
2145 | struct console *con; | |
2146 | ||
2147 | for_each_console(con) | |
adaf6590 SS |
2148 | if ((con->flags & CON_ENABLED) && |
2149 | (con->flags & CON_ANYTIME)) | |
a8199371 SS |
2150 | return 1; |
2151 | ||
2152 | return 0; | |
2153 | } | |
2154 | ||
2155 | /* | |
2156 | * Can we actually use the console at this time on this cpu? | |
2157 | * | |
2158 | * Console drivers may assume that per-cpu resources have been allocated. So | |
2159 | * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't | |
2160 | * call them until this CPU is officially up. | |
2161 | */ | |
2162 | static inline int can_use_console(void) | |
2163 | { | |
2164 | return cpu_online(raw_smp_processor_id()) || have_callable_console(); | |
2165 | } | |
2166 | ||
eab07260 KS |
2167 | static void console_cont_flush(char *text, size_t size) |
2168 | { | |
2169 | unsigned long flags; | |
2170 | size_t len; | |
2171 | ||
2172 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2173 | ||
2174 | if (!cont.len) | |
2175 | goto out; | |
2176 | ||
2177 | /* | |
2178 | * We still queue earlier records, likely because the console was | |
2179 | * busy. The earlier ones need to be printed before this one, we | |
2180 | * did not flush any fragment so far, so just let it queue up. | |
2181 | */ | |
2182 | if (console_seq < log_next_seq && !cont.cons) | |
2183 | goto out; | |
2184 | ||
2185 | len = cont_print_text(text, size); | |
2186 | raw_spin_unlock(&logbuf_lock); | |
2187 | stop_critical_timings(); | |
6fe29354 | 2188 | call_console_drivers(cont.level, NULL, 0, text, len); |
eab07260 KS |
2189 | start_critical_timings(); |
2190 | local_irq_restore(flags); | |
2191 | return; | |
2192 | out: | |
2193 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2194 | } | |
7ff9554b | 2195 | |
1da177e4 | 2196 | /** |
ac751efa | 2197 | * console_unlock - unlock the console system |
1da177e4 | 2198 | * |
ac751efa | 2199 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2200 | * and the console driver list. |
2201 | * | |
ac751efa TH |
2202 | * While the console_lock was held, console output may have been buffered |
2203 | * by printk(). If this is the case, console_unlock(); emits | |
2204 | * the output prior to releasing the lock. | |
1da177e4 | 2205 | * |
7f3a781d | 2206 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2207 | * |
ac751efa | 2208 | * console_unlock(); may be called from any context. |
1da177e4 | 2209 | */ |
ac751efa | 2210 | void console_unlock(void) |
1da177e4 | 2211 | { |
6fe29354 | 2212 | static char ext_text[CONSOLE_EXT_LOG_MAX]; |
70498253 | 2213 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2214 | static u64 seen_seq; |
1da177e4 | 2215 | unsigned long flags; |
7ff9554b | 2216 | bool wake_klogd = false; |
8d91f8b1 | 2217 | bool do_cond_resched, retry; |
1da177e4 | 2218 | |
557240b4 | 2219 | if (console_suspended) { |
bd8d7cf5 | 2220 | up_console_sem(); |
557240b4 LT |
2221 | return; |
2222 | } | |
78944e54 | 2223 | |
8d91f8b1 TH |
2224 | /* |
2225 | * Console drivers are called under logbuf_lock, so | |
2226 | * @console_may_schedule should be cleared before; however, we may | |
2227 | * end up dumping a lot of lines, for example, if called from | |
2228 | * console registration path, and should invoke cond_resched() | |
2229 | * between lines if allowable. Not doing so can cause a very long | |
2230 | * scheduling stall on a slow console leading to RCU stall and | |
2231 | * softlockup warnings which exacerbate the issue with more | |
2232 | * messages practically incapacitating the system. | |
2233 | */ | |
2234 | do_cond_resched = console_may_schedule; | |
78944e54 AD |
2235 | console_may_schedule = 0; |
2236 | ||
a8199371 SS |
2237 | again: |
2238 | /* | |
2239 | * We released the console_sem lock, so we need to recheck if | |
2240 | * cpu is online and (if not) is there at least one CON_ANYTIME | |
2241 | * console. | |
2242 | */ | |
2243 | if (!can_use_console()) { | |
2244 | console_locked = 0; | |
2245 | up_console_sem(); | |
2246 | return; | |
2247 | } | |
2248 | ||
084681d1 | 2249 | /* flush buffered message fragment immediately to console */ |
eab07260 | 2250 | console_cont_flush(text, sizeof(text)); |
a8199371 | 2251 | |
7ff9554b | 2252 | for (;;) { |
62e32ac3 | 2253 | struct printk_log *msg; |
6fe29354 | 2254 | size_t ext_len = 0; |
3ce9a7c0 | 2255 | size_t len; |
7ff9554b KS |
2256 | int level; |
2257 | ||
07354eb1 | 2258 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2259 | if (seen_seq != log_next_seq) { |
2260 | wake_klogd = true; | |
2261 | seen_seq = log_next_seq; | |
2262 | } | |
2263 | ||
2264 | if (console_seq < log_first_seq) { | |
84b5ec8a WD |
2265 | len = sprintf(text, "** %u printk messages dropped ** ", |
2266 | (unsigned)(log_first_seq - console_seq)); | |
2267 | ||
7ff9554b KS |
2268 | /* messages are gone, move to first one */ |
2269 | console_seq = log_first_seq; | |
2270 | console_idx = log_first_idx; | |
5becfb1d | 2271 | console_prev = 0; |
84b5ec8a WD |
2272 | } else { |
2273 | len = 0; | |
7ff9554b | 2274 | } |
084681d1 | 2275 | skip: |
7ff9554b KS |
2276 | if (console_seq == log_next_seq) |
2277 | break; | |
2278 | ||
2279 | msg = log_from_idx(console_idx); | |
084681d1 KS |
2280 | if (msg->flags & LOG_NOCONS) { |
2281 | /* | |
2282 | * Skip record we have buffered and already printed | |
2283 | * directly to the console when we received it. | |
2284 | */ | |
2285 | console_idx = log_next(console_idx); | |
2286 | console_seq++; | |
68b6507d KS |
2287 | /* |
2288 | * We will get here again when we register a new | |
2289 | * CON_PRINTBUFFER console. Clear the flag so we | |
2290 | * will properly dump everything later. | |
2291 | */ | |
2292 | msg->flags &= ~LOG_NOCONS; | |
eab07260 | 2293 | console_prev = msg->flags; |
084681d1 KS |
2294 | goto skip; |
2295 | } | |
649e6ee3 | 2296 | |
084681d1 | 2297 | level = msg->level; |
84b5ec8a WD |
2298 | len += msg_print_text(msg, console_prev, false, |
2299 | text + len, sizeof(text) - len); | |
6fe29354 TH |
2300 | if (nr_ext_console_drivers) { |
2301 | ext_len = msg_print_ext_header(ext_text, | |
2302 | sizeof(ext_text), | |
2303 | msg, console_seq, console_prev); | |
2304 | ext_len += msg_print_ext_body(ext_text + ext_len, | |
2305 | sizeof(ext_text) - ext_len, | |
2306 | log_dict(msg), msg->dict_len, | |
2307 | log_text(msg), msg->text_len); | |
2308 | } | |
7ff9554b KS |
2309 | console_idx = log_next(console_idx); |
2310 | console_seq++; | |
5becfb1d | 2311 | console_prev = msg->flags; |
07354eb1 | 2312 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2313 | |
81d68a96 | 2314 | stop_critical_timings(); /* don't trace print latency */ |
6fe29354 | 2315 | call_console_drivers(level, ext_text, ext_len, text, len); |
81d68a96 | 2316 | start_critical_timings(); |
1da177e4 | 2317 | local_irq_restore(flags); |
8d91f8b1 TH |
2318 | |
2319 | if (do_cond_resched) | |
2320 | cond_resched(); | |
1da177e4 LT |
2321 | } |
2322 | console_locked = 0; | |
fe3d8ad3 FT |
2323 | |
2324 | /* Release the exclusive_console once it is used */ | |
2325 | if (unlikely(exclusive_console)) | |
2326 | exclusive_console = NULL; | |
2327 | ||
07354eb1 | 2328 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2329 | |
bd8d7cf5 | 2330 | up_console_sem(); |
4f2a8d3c PZ |
2331 | |
2332 | /* | |
2333 | * Someone could have filled up the buffer again, so re-check if there's | |
2334 | * something to flush. In case we cannot trylock the console_sem again, | |
2335 | * there's a new owner and the console_unlock() from them will do the | |
2336 | * flush, no worries. | |
2337 | */ | |
07354eb1 | 2338 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2339 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2340 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2341 | ||
4f2a8d3c PZ |
2342 | if (retry && console_trylock()) |
2343 | goto again; | |
2344 | ||
e3e8a75d KK |
2345 | if (wake_klogd) |
2346 | wake_up_klogd(); | |
1da177e4 | 2347 | } |
ac751efa | 2348 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2349 | |
ddad86c2 MW |
2350 | /** |
2351 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2352 | * |
2353 | * If the console code is currently allowed to sleep, and | |
2354 | * if this CPU should yield the CPU to another task, do | |
2355 | * so here. | |
2356 | * | |
ac751efa | 2357 | * Must be called within console_lock();. |
1da177e4 LT |
2358 | */ |
2359 | void __sched console_conditional_schedule(void) | |
2360 | { | |
2361 | if (console_may_schedule) | |
2362 | cond_resched(); | |
2363 | } | |
2364 | EXPORT_SYMBOL(console_conditional_schedule); | |
2365 | ||
1da177e4 LT |
2366 | void console_unblank(void) |
2367 | { | |
2368 | struct console *c; | |
2369 | ||
2370 | /* | |
2371 | * console_unblank can no longer be called in interrupt context unless | |
2372 | * oops_in_progress is set to 1.. | |
2373 | */ | |
2374 | if (oops_in_progress) { | |
bd8d7cf5 | 2375 | if (down_trylock_console_sem() != 0) |
1da177e4 LT |
2376 | return; |
2377 | } else | |
ac751efa | 2378 | console_lock(); |
1da177e4 LT |
2379 | |
2380 | console_locked = 1; | |
2381 | console_may_schedule = 0; | |
4d091611 | 2382 | for_each_console(c) |
1da177e4 LT |
2383 | if ((c->flags & CON_ENABLED) && c->unblank) |
2384 | c->unblank(); | |
ac751efa | 2385 | console_unlock(); |
1da177e4 | 2386 | } |
1da177e4 | 2387 | |
8d91f8b1 TH |
2388 | /** |
2389 | * console_flush_on_panic - flush console content on panic | |
2390 | * | |
2391 | * Immediately output all pending messages no matter what. | |
2392 | */ | |
2393 | void console_flush_on_panic(void) | |
2394 | { | |
2395 | /* | |
2396 | * If someone else is holding the console lock, trylock will fail | |
2397 | * and may_schedule may be set. Ignore and proceed to unlock so | |
2398 | * that messages are flushed out. As this can be called from any | |
2399 | * context and we don't want to get preempted while flushing, | |
2400 | * ensure may_schedule is cleared. | |
2401 | */ | |
2402 | console_trylock(); | |
2403 | console_may_schedule = 0; | |
2404 | console_unlock(); | |
2405 | } | |
2406 | ||
1da177e4 LT |
2407 | /* |
2408 | * Return the console tty driver structure and its associated index | |
2409 | */ | |
2410 | struct tty_driver *console_device(int *index) | |
2411 | { | |
2412 | struct console *c; | |
2413 | struct tty_driver *driver = NULL; | |
2414 | ||
ac751efa | 2415 | console_lock(); |
4d091611 | 2416 | for_each_console(c) { |
1da177e4 LT |
2417 | if (!c->device) |
2418 | continue; | |
2419 | driver = c->device(c, index); | |
2420 | if (driver) | |
2421 | break; | |
2422 | } | |
ac751efa | 2423 | console_unlock(); |
1da177e4 LT |
2424 | return driver; |
2425 | } | |
2426 | ||
2427 | /* | |
2428 | * Prevent further output on the passed console device so that (for example) | |
2429 | * serial drivers can disable console output before suspending a port, and can | |
2430 | * re-enable output afterwards. | |
2431 | */ | |
2432 | void console_stop(struct console *console) | |
2433 | { | |
ac751efa | 2434 | console_lock(); |
1da177e4 | 2435 | console->flags &= ~CON_ENABLED; |
ac751efa | 2436 | console_unlock(); |
1da177e4 LT |
2437 | } |
2438 | EXPORT_SYMBOL(console_stop); | |
2439 | ||
2440 | void console_start(struct console *console) | |
2441 | { | |
ac751efa | 2442 | console_lock(); |
1da177e4 | 2443 | console->flags |= CON_ENABLED; |
ac751efa | 2444 | console_unlock(); |
1da177e4 LT |
2445 | } |
2446 | EXPORT_SYMBOL(console_start); | |
2447 | ||
7bf69395 FDN |
2448 | static int __read_mostly keep_bootcon; |
2449 | ||
2450 | static int __init keep_bootcon_setup(char *str) | |
2451 | { | |
2452 | keep_bootcon = 1; | |
27083bac | 2453 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2454 | |
2455 | return 0; | |
2456 | } | |
2457 | ||
2458 | early_param("keep_bootcon", keep_bootcon_setup); | |
2459 | ||
1da177e4 LT |
2460 | /* |
2461 | * The console driver calls this routine during kernel initialization | |
2462 | * to register the console printing procedure with printk() and to | |
2463 | * print any messages that were printed by the kernel before the | |
2464 | * console driver was initialized. | |
4d091611 RG |
2465 | * |
2466 | * This can happen pretty early during the boot process (because of | |
2467 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2468 | * of what kernel features are used - they may not be initialised yet. | |
2469 | * | |
2470 | * There are two types of consoles - bootconsoles (early_printk) and | |
2471 | * "real" consoles (everything which is not a bootconsole) which are | |
2472 | * handled differently. | |
2473 | * - Any number of bootconsoles can be registered at any time. | |
2474 | * - As soon as a "real" console is registered, all bootconsoles | |
2475 | * will be unregistered automatically. | |
2476 | * - Once a "real" console is registered, any attempt to register a | |
2477 | * bootconsoles will be rejected | |
1da177e4 | 2478 | */ |
4d091611 | 2479 | void register_console(struct console *newcon) |
1da177e4 | 2480 | { |
40dc5651 | 2481 | int i; |
1da177e4 | 2482 | unsigned long flags; |
4d091611 | 2483 | struct console *bcon = NULL; |
23475408 | 2484 | struct console_cmdline *c; |
1da177e4 | 2485 | |
16cf48a6 AB |
2486 | if (console_drivers) |
2487 | for_each_console(bcon) | |
2488 | if (WARN(bcon == newcon, | |
2489 | "console '%s%d' already registered\n", | |
2490 | bcon->name, bcon->index)) | |
2491 | return; | |
2492 | ||
4d091611 RG |
2493 | /* |
2494 | * before we register a new CON_BOOT console, make sure we don't | |
2495 | * already have a valid console | |
2496 | */ | |
2497 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2498 | /* find the last or real console */ | |
2499 | for_each_console(bcon) { | |
2500 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2501 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2502 | newcon->name, newcon->index); |
2503 | return; | |
2504 | } | |
2505 | } | |
69331af7 GH |
2506 | } |
2507 | ||
4d091611 RG |
2508 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2509 | bcon = console_drivers; | |
2510 | ||
2511 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2512 | preferred_console = selected_console; |
2513 | ||
2514 | /* | |
2515 | * See if we want to use this console driver. If we | |
2516 | * didn't select a console we take the first one | |
2517 | * that registers here. | |
2518 | */ | |
2519 | if (preferred_console < 0) { | |
4d091611 RG |
2520 | if (newcon->index < 0) |
2521 | newcon->index = 0; | |
2522 | if (newcon->setup == NULL || | |
2523 | newcon->setup(newcon, NULL) == 0) { | |
2524 | newcon->flags |= CON_ENABLED; | |
2525 | if (newcon->device) { | |
2526 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2527 | preferred_console = 0; |
2528 | } | |
1da177e4 LT |
2529 | } |
2530 | } | |
2531 | ||
2532 | /* | |
2533 | * See if this console matches one we selected on | |
2534 | * the command line. | |
2535 | */ | |
23475408 JP |
2536 | for (i = 0, c = console_cmdline; |
2537 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
2538 | i++, c++) { | |
c7cef0a8 PH |
2539 | if (!newcon->match || |
2540 | newcon->match(newcon, c->name, c->index, c->options) != 0) { | |
2541 | /* default matching */ | |
2542 | BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); | |
2543 | if (strcmp(c->name, newcon->name) != 0) | |
2544 | continue; | |
2545 | if (newcon->index >= 0 && | |
2546 | newcon->index != c->index) | |
2547 | continue; | |
2548 | if (newcon->index < 0) | |
2549 | newcon->index = c->index; | |
bbeddf52 | 2550 | |
c7cef0a8 PH |
2551 | if (_braille_register_console(newcon, c)) |
2552 | return; | |
2553 | ||
2554 | if (newcon->setup && | |
2555 | newcon->setup(newcon, c->options) != 0) | |
2556 | break; | |
2557 | } | |
bbeddf52 | 2558 | |
4d091611 | 2559 | newcon->flags |= CON_ENABLED; |
ab4af03a | 2560 | if (i == selected_console) { |
4d091611 | 2561 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2562 | preferred_console = selected_console; |
2563 | } | |
1da177e4 LT |
2564 | break; |
2565 | } | |
2566 | ||
4d091611 | 2567 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2568 | return; |
2569 | ||
8259cf43 RG |
2570 | /* |
2571 | * If we have a bootconsole, and are switching to a real console, | |
2572 | * don't print everything out again, since when the boot console, and | |
2573 | * the real console are the same physical device, it's annoying to | |
2574 | * see the beginning boot messages twice | |
2575 | */ | |
2576 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2577 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2578 | |
2579 | /* | |
2580 | * Put this console in the list - keep the | |
2581 | * preferred driver at the head of the list. | |
2582 | */ | |
ac751efa | 2583 | console_lock(); |
4d091611 RG |
2584 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2585 | newcon->next = console_drivers; | |
2586 | console_drivers = newcon; | |
2587 | if (newcon->next) | |
2588 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2589 | } else { |
4d091611 RG |
2590 | newcon->next = console_drivers->next; |
2591 | console_drivers->next = newcon; | |
1da177e4 | 2592 | } |
6fe29354 TH |
2593 | |
2594 | if (newcon->flags & CON_EXTENDED) | |
2595 | if (!nr_ext_console_drivers++) | |
2596 | pr_info("printk: continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n"); | |
2597 | ||
4d091611 | 2598 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2599 | /* |
ac751efa | 2600 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2601 | * for us. |
2602 | */ | |
07354eb1 | 2603 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2604 | console_seq = syslog_seq; |
2605 | console_idx = syslog_idx; | |
5becfb1d | 2606 | console_prev = syslog_prev; |
07354eb1 | 2607 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2608 | /* |
2609 | * We're about to replay the log buffer. Only do this to the | |
2610 | * just-registered console to avoid excessive message spam to | |
2611 | * the already-registered consoles. | |
2612 | */ | |
2613 | exclusive_console = newcon; | |
1da177e4 | 2614 | } |
ac751efa | 2615 | console_unlock(); |
fbc92a34 | 2616 | console_sysfs_notify(); |
8259cf43 RG |
2617 | |
2618 | /* | |
2619 | * By unregistering the bootconsoles after we enable the real console | |
2620 | * we get the "console xxx enabled" message on all the consoles - | |
2621 | * boot consoles, real consoles, etc - this is to ensure that end | |
2622 | * users know there might be something in the kernel's log buffer that | |
2623 | * went to the bootconsole (that they do not see on the real console) | |
2624 | */ | |
27083bac | 2625 | pr_info("%sconsole [%s%d] enabled\n", |
6b802394 KC |
2626 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
2627 | newcon->name, newcon->index); | |
7bf69395 FDN |
2628 | if (bcon && |
2629 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2630 | !keep_bootcon) { | |
6b802394 KC |
2631 | /* We need to iterate through all boot consoles, to make |
2632 | * sure we print everything out, before we unregister them. | |
8259cf43 | 2633 | */ |
8259cf43 RG |
2634 | for_each_console(bcon) |
2635 | if (bcon->flags & CON_BOOT) | |
2636 | unregister_console(bcon); | |
8259cf43 | 2637 | } |
1da177e4 LT |
2638 | } |
2639 | EXPORT_SYMBOL(register_console); | |
2640 | ||
40dc5651 | 2641 | int unregister_console(struct console *console) |
1da177e4 | 2642 | { |
40dc5651 | 2643 | struct console *a, *b; |
bbeddf52 | 2644 | int res; |
1da177e4 | 2645 | |
27083bac | 2646 | pr_info("%sconsole [%s%d] disabled\n", |
6b802394 KC |
2647 | (console->flags & CON_BOOT) ? "boot" : "" , |
2648 | console->name, console->index); | |
2649 | ||
bbeddf52 JP |
2650 | res = _braille_unregister_console(console); |
2651 | if (res) | |
2652 | return res; | |
f7511d5f | 2653 | |
bbeddf52 | 2654 | res = 1; |
ac751efa | 2655 | console_lock(); |
1da177e4 LT |
2656 | if (console_drivers == console) { |
2657 | console_drivers=console->next; | |
2658 | res = 0; | |
e9b15b54 | 2659 | } else if (console_drivers) { |
1da177e4 LT |
2660 | for (a=console_drivers->next, b=console_drivers ; |
2661 | a; b=a, a=b->next) { | |
2662 | if (a == console) { | |
2663 | b->next = a->next; | |
2664 | res = 0; | |
2665 | break; | |
40dc5651 | 2666 | } |
1da177e4 LT |
2667 | } |
2668 | } | |
40dc5651 | 2669 | |
6fe29354 TH |
2670 | if (!res && (console->flags & CON_EXTENDED)) |
2671 | nr_ext_console_drivers--; | |
2672 | ||
69331af7 | 2673 | /* |
ab4af03a GE |
2674 | * If this isn't the last console and it has CON_CONSDEV set, we |
2675 | * need to set it on the next preferred console. | |
1da177e4 | 2676 | */ |
69331af7 | 2677 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2678 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2679 | |
7fa21dd8 | 2680 | console->flags &= ~CON_ENABLED; |
ac751efa | 2681 | console_unlock(); |
fbc92a34 | 2682 | console_sysfs_notify(); |
1da177e4 LT |
2683 | return res; |
2684 | } | |
2685 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2686 | |
81cc26f2 TR |
2687 | /* |
2688 | * Some boot consoles access data that is in the init section and which will | |
2689 | * be discarded after the initcalls have been run. To make sure that no code | |
2690 | * will access this data, unregister the boot consoles in a late initcall. | |
2691 | * | |
2692 | * If for some reason, such as deferred probe or the driver being a loadable | |
2693 | * module, the real console hasn't registered yet at this point, there will | |
2694 | * be a brief interval in which no messages are logged to the console, which | |
2695 | * makes it difficult to diagnose problems that occur during this time. | |
2696 | * | |
2697 | * To mitigate this problem somewhat, only unregister consoles whose memory | |
2698 | * intersects with the init section. Note that code exists elsewhere to get | |
2699 | * rid of the boot console as soon as the proper console shows up, so there | |
2700 | * won't be side-effects from postponing the removal. | |
2701 | */ | |
034260d6 | 2702 | static int __init printk_late_init(void) |
0c5564bd | 2703 | { |
4d091611 RG |
2704 | struct console *con; |
2705 | ||
2706 | for_each_console(con) { | |
4c30c6f5 | 2707 | if (!keep_bootcon && con->flags & CON_BOOT) { |
81cc26f2 TR |
2708 | /* |
2709 | * Make sure to unregister boot consoles whose data | |
2710 | * resides in the init section before the init section | |
2711 | * is discarded. Boot consoles whose data will stick | |
2712 | * around will automatically be unregistered when the | |
2713 | * proper console replaces them. | |
2714 | */ | |
2715 | if (init_section_intersects(con, sizeof(*con))) | |
2716 | unregister_console(con); | |
cb00e99c | 2717 | } |
0c5564bd | 2718 | } |
034260d6 | 2719 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2720 | return 0; |
2721 | } | |
034260d6 | 2722 | late_initcall(printk_late_init); |
0c5564bd | 2723 | |
7ef3d2fd | 2724 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2725 | /* |
2726 | * Delayed printk version, for scheduler-internal messages: | |
2727 | */ | |
dc72c32e | 2728 | #define PRINTK_PENDING_WAKEUP 0x01 |
458df9fd | 2729 | #define PRINTK_PENDING_OUTPUT 0x02 |
dc72c32e FW |
2730 | |
2731 | static DEFINE_PER_CPU(int, printk_pending); | |
dc72c32e FW |
2732 | |
2733 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2734 | { | |
2735 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2736 | ||
458df9fd SR |
2737 | if (pending & PRINTK_PENDING_OUTPUT) { |
2738 | /* If trylock fails, someone else is doing the printing */ | |
2739 | if (console_trylock()) | |
2740 | console_unlock(); | |
dc72c32e FW |
2741 | } |
2742 | ||
2743 | if (pending & PRINTK_PENDING_WAKEUP) | |
2744 | wake_up_interruptible(&log_wait); | |
2745 | } | |
2746 | ||
2747 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2748 | .func = wake_up_klogd_work_func, | |
2749 | .flags = IRQ_WORK_LAZY, | |
2750 | }; | |
2751 | ||
2752 | void wake_up_klogd(void) | |
2753 | { | |
2754 | preempt_disable(); | |
2755 | if (waitqueue_active(&log_wait)) { | |
2756 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
bb964a92 | 2757 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
dc72c32e FW |
2758 | } |
2759 | preempt_enable(); | |
2760 | } | |
717115e1 | 2761 | |
aac74dc4 | 2762 | int printk_deferred(const char *fmt, ...) |
600e1458 | 2763 | { |
600e1458 | 2764 | va_list args; |
600e1458 PZ |
2765 | int r; |
2766 | ||
81954606 | 2767 | preempt_disable(); |
600e1458 | 2768 | va_start(args, fmt); |
a39d4a85 | 2769 | r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); |
600e1458 PZ |
2770 | va_end(args); |
2771 | ||
458df9fd | 2772 | __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); |
bb964a92 | 2773 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
81954606 | 2774 | preempt_enable(); |
600e1458 PZ |
2775 | |
2776 | return r; | |
2777 | } | |
2778 | ||
1da177e4 LT |
2779 | /* |
2780 | * printk rate limiting, lifted from the networking subsystem. | |
2781 | * | |
641de9d8 UKK |
2782 | * This enforces a rate limit: not more than 10 kernel messages |
2783 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2784 | */ |
641de9d8 UKK |
2785 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2786 | ||
5c828713 | 2787 | int __printk_ratelimit(const char *func) |
1da177e4 | 2788 | { |
5c828713 | 2789 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2790 | } |
5c828713 | 2791 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2792 | |
2793 | /** | |
2794 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2795 | * @caller_jiffies: pointer to caller's state | |
2796 | * @interval_msecs: minimum interval between prints | |
2797 | * | |
2798 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2799 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2800 | * returned true. | |
2801 | */ | |
2802 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2803 | unsigned int interval_msecs) | |
2804 | { | |
249771b8 AE |
2805 | unsigned long elapsed = jiffies - *caller_jiffies; |
2806 | ||
2807 | if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) | |
2808 | return false; | |
2809 | ||
2810 | *caller_jiffies = jiffies; | |
2811 | return true; | |
f46c4833 AM |
2812 | } |
2813 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2814 | |
2815 | static DEFINE_SPINLOCK(dump_list_lock); | |
2816 | static LIST_HEAD(dump_list); | |
2817 | ||
2818 | /** | |
2819 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2820 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2821 | * |
2822 | * Adds a kernel log dumper to the system. The dump callback in the | |
2823 | * structure will be called when the kernel oopses or panics and must be | |
2824 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2825 | */ | |
2826 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2827 | { | |
2828 | unsigned long flags; | |
2829 | int err = -EBUSY; | |
2830 | ||
2831 | /* The dump callback needs to be set */ | |
2832 | if (!dumper->dump) | |
2833 | return -EINVAL; | |
2834 | ||
2835 | spin_lock_irqsave(&dump_list_lock, flags); | |
2836 | /* Don't allow registering multiple times */ | |
2837 | if (!dumper->registered) { | |
2838 | dumper->registered = 1; | |
fb842b00 | 2839 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2840 | err = 0; |
2841 | } | |
2842 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2843 | ||
2844 | return err; | |
2845 | } | |
2846 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2847 | ||
2848 | /** | |
2849 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2850 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2851 | * |
2852 | * Removes a dump device from the system. Returns zero on success and | |
2853 | * %-EINVAL otherwise. | |
2854 | */ | |
2855 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2856 | { | |
2857 | unsigned long flags; | |
2858 | int err = -EINVAL; | |
2859 | ||
2860 | spin_lock_irqsave(&dump_list_lock, flags); | |
2861 | if (dumper->registered) { | |
2862 | dumper->registered = 0; | |
fb842b00 | 2863 | list_del_rcu(&dumper->list); |
456b565c SK |
2864 | err = 0; |
2865 | } | |
2866 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2867 | synchronize_rcu(); |
456b565c SK |
2868 | |
2869 | return err; | |
2870 | } | |
2871 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2872 | ||
7ff9554b KS |
2873 | static bool always_kmsg_dump; |
2874 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2875 | ||
456b565c SK |
2876 | /** |
2877 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2878 | * @reason: the reason (oops, panic etc) for dumping | |
2879 | * | |
e2ae715d KS |
2880 | * Call each of the registered dumper's dump() callback, which can |
2881 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2882 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2883 | */ |
2884 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2885 | { | |
456b565c | 2886 | struct kmsg_dumper *dumper; |
456b565c SK |
2887 | unsigned long flags; |
2888 | ||
c22ab332 MG |
2889 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2890 | return; | |
2891 | ||
e2ae715d KS |
2892 | rcu_read_lock(); |
2893 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2894 | if (dumper->max_reason && reason > dumper->max_reason) | |
2895 | continue; | |
2896 | ||
2897 | /* initialize iterator with data about the stored records */ | |
2898 | dumper->active = true; | |
2899 | ||
2900 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2901 | dumper->cur_seq = clear_seq; | |
2902 | dumper->cur_idx = clear_idx; | |
2903 | dumper->next_seq = log_next_seq; | |
2904 | dumper->next_idx = log_next_idx; | |
2905 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2906 | ||
2907 | /* invoke dumper which will iterate over records */ | |
2908 | dumper->dump(dumper, reason); | |
2909 | ||
2910 | /* reset iterator */ | |
2911 | dumper->active = false; | |
2912 | } | |
2913 | rcu_read_unlock(); | |
2914 | } | |
2915 | ||
2916 | /** | |
533827c9 | 2917 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2918 | * @dumper: registered kmsg dumper |
2919 | * @syslog: include the "<4>" prefixes | |
2920 | * @line: buffer to copy the line to | |
2921 | * @size: maximum size of the buffer | |
2922 | * @len: length of line placed into buffer | |
2923 | * | |
2924 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2925 | * record, and copy one record into the provided buffer. | |
2926 | * | |
2927 | * Consecutive calls will return the next available record moving | |
2928 | * towards the end of the buffer with the youngest messages. | |
2929 | * | |
2930 | * A return value of FALSE indicates that there are no more records to | |
2931 | * read. | |
533827c9 AV |
2932 | * |
2933 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2934 | */ |
533827c9 AV |
2935 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2936 | char *line, size_t size, size_t *len) | |
e2ae715d | 2937 | { |
62e32ac3 | 2938 | struct printk_log *msg; |
e2ae715d KS |
2939 | size_t l = 0; |
2940 | bool ret = false; | |
2941 | ||
2942 | if (!dumper->active) | |
2943 | goto out; | |
7ff9554b | 2944 | |
e2ae715d KS |
2945 | if (dumper->cur_seq < log_first_seq) { |
2946 | /* messages are gone, move to first available one */ | |
2947 | dumper->cur_seq = log_first_seq; | |
2948 | dumper->cur_idx = log_first_idx; | |
2949 | } | |
456b565c | 2950 | |
e2ae715d | 2951 | /* last entry */ |
533827c9 | 2952 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2953 | goto out; |
456b565c | 2954 | |
e2ae715d | 2955 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2956 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2957 | |
2958 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2959 | dumper->cur_seq++; | |
2960 | ret = true; | |
e2ae715d KS |
2961 | out: |
2962 | if (len) | |
2963 | *len = l; | |
2964 | return ret; | |
2965 | } | |
533827c9 AV |
2966 | |
2967 | /** | |
2968 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2969 | * @dumper: registered kmsg dumper | |
2970 | * @syslog: include the "<4>" prefixes | |
2971 | * @line: buffer to copy the line to | |
2972 | * @size: maximum size of the buffer | |
2973 | * @len: length of line placed into buffer | |
2974 | * | |
2975 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2976 | * record, and copy one record into the provided buffer. | |
2977 | * | |
2978 | * Consecutive calls will return the next available record moving | |
2979 | * towards the end of the buffer with the youngest messages. | |
2980 | * | |
2981 | * A return value of FALSE indicates that there are no more records to | |
2982 | * read. | |
2983 | */ | |
2984 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2985 | char *line, size_t size, size_t *len) | |
2986 | { | |
2987 | unsigned long flags; | |
2988 | bool ret; | |
2989 | ||
2990 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2991 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2992 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2993 | ||
2994 | return ret; | |
2995 | } | |
e2ae715d KS |
2996 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2997 | ||
2998 | /** | |
2999 | * kmsg_dump_get_buffer - copy kmsg log lines | |
3000 | * @dumper: registered kmsg dumper | |
3001 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 3002 | * @buf: buffer to copy the line to |
e2ae715d KS |
3003 | * @size: maximum size of the buffer |
3004 | * @len: length of line placed into buffer | |
3005 | * | |
3006 | * Start at the end of the kmsg buffer and fill the provided buffer | |
3007 | * with as many of the the *youngest* kmsg records that fit into it. | |
3008 | * If the buffer is large enough, all available kmsg records will be | |
3009 | * copied with a single call. | |
3010 | * | |
3011 | * Consecutive calls will fill the buffer with the next block of | |
3012 | * available older records, not including the earlier retrieved ones. | |
3013 | * | |
3014 | * A return value of FALSE indicates that there are no more records to | |
3015 | * read. | |
3016 | */ | |
3017 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
3018 | char *buf, size_t size, size_t *len) | |
3019 | { | |
3020 | unsigned long flags; | |
3021 | u64 seq; | |
3022 | u32 idx; | |
3023 | u64 next_seq; | |
3024 | u32 next_idx; | |
5becfb1d | 3025 | enum log_flags prev; |
e2ae715d KS |
3026 | size_t l = 0; |
3027 | bool ret = false; | |
3028 | ||
3029 | if (!dumper->active) | |
3030 | goto out; | |
3031 | ||
3032 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
3033 | if (dumper->cur_seq < log_first_seq) { | |
3034 | /* messages are gone, move to first available one */ | |
3035 | dumper->cur_seq = log_first_seq; | |
3036 | dumper->cur_idx = log_first_idx; | |
3037 | } | |
3038 | ||
3039 | /* last entry */ | |
3040 | if (dumper->cur_seq >= dumper->next_seq) { | |
3041 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
3042 | goto out; | |
3043 | } | |
3044 | ||
3045 | /* calculate length of entire buffer */ | |
3046 | seq = dumper->cur_seq; | |
3047 | idx = dumper->cur_idx; | |
5becfb1d | 3048 | prev = 0; |
e2ae715d | 3049 | while (seq < dumper->next_seq) { |
62e32ac3 | 3050 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3051 | |
5becfb1d | 3052 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
3053 | idx = log_next(idx); |
3054 | seq++; | |
5becfb1d | 3055 | prev = msg->flags; |
e2ae715d KS |
3056 | } |
3057 | ||
3058 | /* move first record forward until length fits into the buffer */ | |
3059 | seq = dumper->cur_seq; | |
3060 | idx = dumper->cur_idx; | |
5becfb1d | 3061 | prev = 0; |
e2ae715d | 3062 | while (l > size && seq < dumper->next_seq) { |
62e32ac3 | 3063 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 3064 | |
5becfb1d | 3065 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
3066 | idx = log_next(idx); |
3067 | seq++; | |
5becfb1d | 3068 | prev = msg->flags; |
456b565c | 3069 | } |
e2ae715d KS |
3070 | |
3071 | /* last message in next interation */ | |
3072 | next_seq = seq; | |
3073 | next_idx = idx; | |
3074 | ||
3075 | l = 0; | |
3076 | while (seq < dumper->next_seq) { | |
62e32ac3 | 3077 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3078 | |
5becfb1d | 3079 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
3080 | idx = log_next(idx); |
3081 | seq++; | |
5becfb1d | 3082 | prev = msg->flags; |
e2ae715d KS |
3083 | } |
3084 | ||
3085 | dumper->next_seq = next_seq; | |
3086 | dumper->next_idx = next_idx; | |
3087 | ret = true; | |
7ff9554b | 3088 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
3089 | out: |
3090 | if (len) | |
3091 | *len = l; | |
3092 | return ret; | |
3093 | } | |
3094 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 3095 | |
533827c9 AV |
3096 | /** |
3097 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
3098 | * @dumper: registered kmsg dumper | |
3099 | * | |
3100 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3101 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3102 | * times within the same dumper.dump() callback. | |
3103 | * | |
3104 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
3105 | */ | |
3106 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
3107 | { | |
3108 | dumper->cur_seq = clear_seq; | |
3109 | dumper->cur_idx = clear_idx; | |
3110 | dumper->next_seq = log_next_seq; | |
3111 | dumper->next_idx = log_next_idx; | |
3112 | } | |
3113 | ||
e2ae715d KS |
3114 | /** |
3115 | * kmsg_dump_rewind - reset the interator | |
3116 | * @dumper: registered kmsg dumper | |
3117 | * | |
3118 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3119 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3120 | * times within the same dumper.dump() callback. | |
3121 | */ | |
3122 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
3123 | { | |
3124 | unsigned long flags; | |
3125 | ||
3126 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 3127 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 3128 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 3129 | } |
e2ae715d | 3130 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 3131 | |
98e5e1bf TH |
3132 | static char dump_stack_arch_desc_str[128]; |
3133 | ||
3134 | /** | |
3135 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
3136 | * @fmt: printf-style format string | |
3137 | * @...: arguments for the format string | |
3138 | * | |
3139 | * The configured string will be printed right after utsname during task | |
3140 | * dumps. Usually used to add arch-specific system identifiers. If an | |
3141 | * arch wants to make use of such an ID string, it should initialize this | |
3142 | * as soon as possible during boot. | |
3143 | */ | |
3144 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
3145 | { | |
3146 | va_list args; | |
3147 | ||
3148 | va_start(args, fmt); | |
3149 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
3150 | fmt, args); | |
3151 | va_end(args); | |
3152 | } | |
3153 | ||
196779b9 TH |
3154 | /** |
3155 | * dump_stack_print_info - print generic debug info for dump_stack() | |
3156 | * @log_lvl: log level | |
3157 | * | |
3158 | * Arch-specific dump_stack() implementations can use this function to | |
3159 | * print out the same debug information as the generic dump_stack(). | |
3160 | */ | |
3161 | void dump_stack_print_info(const char *log_lvl) | |
3162 | { | |
3163 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
3164 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
3165 | print_tainted(), init_utsname()->release, | |
3166 | (int)strcspn(init_utsname()->version, " "), | |
3167 | init_utsname()->version); | |
98e5e1bf TH |
3168 | |
3169 | if (dump_stack_arch_desc_str[0] != '\0') | |
3170 | printk("%sHardware name: %s\n", | |
3171 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
3172 | |
3173 | print_worker_info(log_lvl, current); | |
196779b9 TH |
3174 | } |
3175 | ||
a43cb95d TH |
3176 | /** |
3177 | * show_regs_print_info - print generic debug info for show_regs() | |
3178 | * @log_lvl: log level | |
3179 | * | |
3180 | * show_regs() implementations can use this function to print out generic | |
3181 | * debug information. | |
3182 | */ | |
3183 | void show_regs_print_info(const char *log_lvl) | |
3184 | { | |
3185 | dump_stack_print_info(log_lvl); | |
3186 | ||
3187 | printk("%stask: %p ti: %p task.ti: %p\n", | |
3188 | log_lvl, current, current_thread_info(), | |
3189 | task_thread_info(current)); | |
3190 | } | |
3191 | ||
7ef3d2fd | 3192 | #endif |