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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 LT |
29 | #include <linux/delay.h> |
30 | #include <linux/smp.h> | |
31 | #include <linux/security.h> | |
32 | #include <linux/bootmem.h> | |
162a7e75 | 33 | #include <linux/memblock.h> |
1da177e4 | 34 | #include <linux/syscalls.h> |
04d491ab | 35 | #include <linux/kexec.h> |
d37d39ae | 36 | #include <linux/kdb.h> |
3fff4c42 | 37 | #include <linux/ratelimit.h> |
456b565c | 38 | #include <linux/kmsg_dump.h> |
00234592 | 39 | #include <linux/syslog.h> |
034260d6 KC |
40 | #include <linux/cpu.h> |
41 | #include <linux/notifier.h> | |
fb842b00 | 42 | #include <linux/rculist.h> |
e11fea92 | 43 | #include <linux/poll.h> |
74876a98 | 44 | #include <linux/irq_work.h> |
196779b9 | 45 | #include <linux/utsname.h> |
249771b8 | 46 | #include <linux/ctype.h> |
e2e40f2c | 47 | #include <linux/uio.h> |
1da177e4 | 48 | |
7c0f6ba6 | 49 | #include <linux/uaccess.h> |
40a7d9f5 | 50 | #include <asm/sections.h> |
1da177e4 | 51 | |
95100358 JB |
52 | #define CREATE_TRACE_POINTS |
53 | #include <trace/events/printk.h> | |
54 | ||
d197c43d | 55 | #include "console_cmdline.h" |
bbeddf52 | 56 | #include "braille.h" |
42a0bb3f | 57 | #include "internal.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 | ||
750afe7b BP |
88 | enum devkmsg_log_bits { |
89 | __DEVKMSG_LOG_BIT_ON = 0, | |
90 | __DEVKMSG_LOG_BIT_OFF, | |
91 | __DEVKMSG_LOG_BIT_LOCK, | |
92 | }; | |
93 | ||
94 | enum devkmsg_log_masks { | |
95 | DEVKMSG_LOG_MASK_ON = BIT(__DEVKMSG_LOG_BIT_ON), | |
96 | DEVKMSG_LOG_MASK_OFF = BIT(__DEVKMSG_LOG_BIT_OFF), | |
97 | DEVKMSG_LOG_MASK_LOCK = BIT(__DEVKMSG_LOG_BIT_LOCK), | |
98 | }; | |
99 | ||
100 | /* Keep both the 'on' and 'off' bits clear, i.e. ratelimit by default: */ | |
101 | #define DEVKMSG_LOG_MASK_DEFAULT 0 | |
102 | ||
103 | static unsigned int __read_mostly devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; | |
104 | ||
105 | static int __control_devkmsg(char *str) | |
106 | { | |
107 | if (!str) | |
108 | return -EINVAL; | |
109 | ||
110 | if (!strncmp(str, "on", 2)) { | |
111 | devkmsg_log = DEVKMSG_LOG_MASK_ON; | |
112 | return 2; | |
113 | } else if (!strncmp(str, "off", 3)) { | |
114 | devkmsg_log = DEVKMSG_LOG_MASK_OFF; | |
115 | return 3; | |
116 | } else if (!strncmp(str, "ratelimit", 9)) { | |
117 | devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; | |
118 | return 9; | |
119 | } | |
120 | return -EINVAL; | |
121 | } | |
122 | ||
123 | static int __init control_devkmsg(char *str) | |
124 | { | |
125 | if (__control_devkmsg(str) < 0) | |
126 | return 1; | |
127 | ||
128 | /* | |
129 | * Set sysctl string accordingly: | |
130 | */ | |
131 | if (devkmsg_log == DEVKMSG_LOG_MASK_ON) { | |
132 | memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE); | |
133 | strncpy(devkmsg_log_str, "on", 2); | |
134 | } else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF) { | |
135 | memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE); | |
136 | strncpy(devkmsg_log_str, "off", 3); | |
137 | } | |
138 | /* else "ratelimit" which is set by default. */ | |
139 | ||
140 | /* | |
141 | * Sysctl cannot change it anymore. The kernel command line setting of | |
142 | * this parameter is to force the setting to be permanent throughout the | |
143 | * runtime of the system. This is a precation measure against userspace | |
144 | * trying to be a smarta** and attempting to change it up on us. | |
145 | */ | |
146 | devkmsg_log |= DEVKMSG_LOG_MASK_LOCK; | |
147 | ||
148 | return 0; | |
149 | } | |
150 | __setup("printk.devkmsg=", control_devkmsg); | |
151 | ||
152 | char devkmsg_log_str[DEVKMSG_STR_MAX_SIZE] = "ratelimit"; | |
153 | ||
154 | int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, | |
155 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
156 | { | |
157 | char old_str[DEVKMSG_STR_MAX_SIZE]; | |
158 | unsigned int old; | |
159 | int err; | |
160 | ||
161 | if (write) { | |
162 | if (devkmsg_log & DEVKMSG_LOG_MASK_LOCK) | |
163 | return -EINVAL; | |
164 | ||
165 | old = devkmsg_log; | |
166 | strncpy(old_str, devkmsg_log_str, DEVKMSG_STR_MAX_SIZE); | |
167 | } | |
168 | ||
169 | err = proc_dostring(table, write, buffer, lenp, ppos); | |
170 | if (err) | |
171 | return err; | |
172 | ||
173 | if (write) { | |
174 | err = __control_devkmsg(devkmsg_log_str); | |
175 | ||
176 | /* | |
177 | * Do not accept an unknown string OR a known string with | |
178 | * trailing crap... | |
179 | */ | |
180 | if (err < 0 || (err + 1 != *lenp)) { | |
181 | ||
182 | /* ... and restore old setting. */ | |
183 | devkmsg_log = old; | |
184 | strncpy(devkmsg_log_str, old_str, DEVKMSG_STR_MAX_SIZE); | |
185 | ||
186 | return -EINVAL; | |
187 | } | |
188 | } | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
6fe29354 TH |
193 | /* |
194 | * Number of registered extended console drivers. | |
195 | * | |
196 | * If extended consoles are present, in-kernel cont reassembly is disabled | |
197 | * and each fragment is stored as a separate log entry with proper | |
198 | * continuation flag so that every emitted message has full metadata. This | |
199 | * doesn't change the result for regular consoles or /proc/kmsg. For | |
200 | * /dev/kmsg, as long as the reader concatenates messages according to | |
201 | * consecutive continuation flags, the end result should be the same too. | |
202 | */ | |
203 | static int nr_ext_console_drivers; | |
204 | ||
bd8d7cf5 JK |
205 | /* |
206 | * Helper macros to handle lockdep when locking/unlocking console_sem. We use | |
207 | * macros instead of functions so that _RET_IP_ contains useful information. | |
208 | */ | |
209 | #define down_console_sem() do { \ | |
210 | down(&console_sem);\ | |
211 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\ | |
212 | } while (0) | |
213 | ||
214 | static int __down_trylock_console_sem(unsigned long ip) | |
215 | { | |
216 | if (down_trylock(&console_sem)) | |
217 | return 1; | |
218 | mutex_acquire(&console_lock_dep_map, 0, 1, ip); | |
219 | return 0; | |
220 | } | |
221 | #define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_) | |
222 | ||
223 | #define up_console_sem() do { \ | |
224 | mutex_release(&console_lock_dep_map, 1, _RET_IP_);\ | |
225 | up(&console_sem);\ | |
226 | } while (0) | |
227 | ||
1da177e4 LT |
228 | /* |
229 | * This is used for debugging the mess that is the VT code by | |
230 | * keeping track if we have the console semaphore held. It's | |
231 | * definitely not the perfect debug tool (we don't know if _WE_ | |
0b90fec3 AE |
232 | * hold it and are racing, but it helps tracking those weird code |
233 | * paths in the console code where we end up in places I want | |
234 | * locked without the console sempahore held). | |
1da177e4 | 235 | */ |
557240b4 | 236 | static int console_locked, console_suspended; |
1da177e4 | 237 | |
fe3d8ad3 FT |
238 | /* |
239 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
240 | */ | |
241 | static struct console *exclusive_console; | |
242 | ||
1da177e4 LT |
243 | /* |
244 | * Array of consoles built from command line options (console=) | |
245 | */ | |
1da177e4 LT |
246 | |
247 | #define MAX_CMDLINECONSOLES 8 | |
248 | ||
249 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
d197c43d | 250 | |
1da177e4 LT |
251 | static int selected_console = -1; |
252 | static int preferred_console = -1; | |
9e124fe1 MA |
253 | int console_set_on_cmdline; |
254 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
255 | |
256 | /* Flag: console code may call schedule() */ | |
257 | static int console_may_schedule; | |
258 | ||
7ff9554b KS |
259 | /* |
260 | * The printk log buffer consists of a chain of concatenated variable | |
261 | * length records. Every record starts with a record header, containing | |
262 | * the overall length of the record. | |
263 | * | |
264 | * The heads to the first and last entry in the buffer, as well as the | |
0b90fec3 AE |
265 | * sequence numbers of these entries are maintained when messages are |
266 | * stored. | |
7ff9554b KS |
267 | * |
268 | * If the heads indicate available messages, the length in the header | |
269 | * tells the start next message. A length == 0 for the next message | |
270 | * indicates a wrap-around to the beginning of the buffer. | |
271 | * | |
272 | * Every record carries the monotonic timestamp in microseconds, as well as | |
273 | * the standard userspace syslog level and syslog facility. The usual | |
274 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
275 | * a matching syslog facility, by default LOG_USER. The origin of every | |
276 | * message can be reliably determined that way. | |
277 | * | |
278 | * The human readable log message directly follows the message header. The | |
279 | * length of the message text is stored in the header, the stored message | |
280 | * is not terminated. | |
281 | * | |
e11fea92 KS |
282 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
283 | * to provide userspace with a machine-readable message context. | |
284 | * | |
285 | * Examples for well-defined, commonly used property names are: | |
286 | * DEVICE=b12:8 device identifier | |
287 | * b12:8 block dev_t | |
288 | * c127:3 char dev_t | |
289 | * n8 netdev ifindex | |
290 | * +sound:card0 subsystem:devname | |
291 | * SUBSYSTEM=pci driver-core subsystem name | |
292 | * | |
293 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
294 | * follows directly after a '=' character. Every property is terminated by | |
295 | * a '\0' character. The last property is not terminated. | |
296 | * | |
297 | * Example of a message structure: | |
298 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
299 | * 0008 34 00 record is 52 bytes long | |
300 | * 000a 0b 00 text is 11 bytes long | |
301 | * 000c 1f 00 dictionary is 23 bytes long | |
302 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
303 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
304 | * 69 6e 65 "ine" | |
305 | * 001b 44 45 56 49 43 "DEVIC" | |
306 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
307 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
308 | * 67 "g" | |
309 | * 0032 00 00 00 padding to next message header | |
310 | * | |
62e32ac3 | 311 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
312 | * userspace, it is a kernel-private implementation detail that might |
313 | * need to be changed in the future, when the requirements change. | |
314 | * | |
315 | * /dev/kmsg exports the structured data in the following line format: | |
b389645f AO |
316 | * "<level>,<sequnum>,<timestamp>,<contflag>[,additional_values, ... ];<message text>\n" |
317 | * | |
318 | * Users of the export format should ignore possible additional values | |
319 | * separated by ',', and find the message after the ';' character. | |
e11fea92 KS |
320 | * |
321 | * The optional key/value pairs are attached as continuation lines starting | |
322 | * with a space character and terminated by a newline. All possible | |
323 | * non-prinatable characters are escaped in the "\xff" notation. | |
7ff9554b KS |
324 | */ |
325 | ||
084681d1 | 326 | enum log_flags { |
5becfb1d KS |
327 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
328 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
329 | LOG_PREFIX = 4, /* text started with a prefix */ | |
330 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
331 | }; |
332 | ||
62e32ac3 | 333 | struct printk_log { |
7ff9554b KS |
334 | u64 ts_nsec; /* timestamp in nanoseconds */ |
335 | u16 len; /* length of entire record */ | |
336 | u16 text_len; /* length of text buffer */ | |
337 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
338 | u8 facility; /* syslog facility */ |
339 | u8 flags:5; /* internal record flags */ | |
340 | u8 level:3; /* syslog level */ | |
5c9cf8af AR |
341 | } |
342 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS | |
343 | __packed __aligned(4) | |
344 | #endif | |
345 | ; | |
7ff9554b KS |
346 | |
347 | /* | |
458df9fd SR |
348 | * The logbuf_lock protects kmsg buffer, indices, counters. This can be taken |
349 | * within the scheduler's rq lock. It must be released before calling | |
350 | * console_unlock() or anything else that might wake up a process. | |
7ff9554b | 351 | */ |
cf9b1106 | 352 | DEFINE_RAW_SPINLOCK(logbuf_lock); |
d59745ce | 353 | |
96efedf1 | 354 | #ifdef CONFIG_PRINTK |
dc72c32e | 355 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
356 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
357 | static u64 syslog_seq; | |
358 | static u32 syslog_idx; | |
eb02dac9 | 359 | static size_t syslog_partial; |
7ff9554b KS |
360 | |
361 | /* index and sequence number of the first record stored in the buffer */ | |
362 | static u64 log_first_seq; | |
363 | static u32 log_first_idx; | |
364 | ||
365 | /* index and sequence number of the next record to store in the buffer */ | |
366 | static u64 log_next_seq; | |
367 | static u32 log_next_idx; | |
368 | ||
eab07260 KS |
369 | /* the next printk record to write to the console */ |
370 | static u64 console_seq; | |
371 | static u32 console_idx; | |
eab07260 | 372 | |
7ff9554b KS |
373 | /* the next printk record to read after the last 'clear' command */ |
374 | static u64 clear_seq; | |
375 | static u32 clear_idx; | |
376 | ||
70498253 | 377 | #define PREFIX_MAX 32 |
249771b8 | 378 | #define LOG_LINE_MAX (1024 - PREFIX_MAX) |
7f3a781d | 379 | |
3824657c MK |
380 | #define LOG_LEVEL(v) ((v) & 0x07) |
381 | #define LOG_FACILITY(v) ((v) >> 3 & 0xff) | |
382 | ||
7f3a781d | 383 | /* record buffer */ |
62e32ac3 | 384 | #define LOG_ALIGN __alignof__(struct printk_log) |
7f3a781d | 385 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 386 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
387 | static char *log_buf = __log_buf; |
388 | static u32 log_buf_len = __LOG_BUF_LEN; | |
389 | ||
14c4000a VH |
390 | /* Return log buffer address */ |
391 | char *log_buf_addr_get(void) | |
392 | { | |
393 | return log_buf; | |
394 | } | |
395 | ||
396 | /* Return log buffer size */ | |
397 | u32 log_buf_len_get(void) | |
398 | { | |
399 | return log_buf_len; | |
400 | } | |
401 | ||
7ff9554b | 402 | /* human readable text of the record */ |
62e32ac3 | 403 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 404 | { |
62e32ac3 | 405 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
406 | } |
407 | ||
408 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 409 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 410 | { |
62e32ac3 | 411 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
412 | } |
413 | ||
414 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 415 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 416 | { |
62e32ac3 | 417 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
418 | |
419 | /* | |
420 | * A length == 0 record is the end of buffer marker. Wrap around and | |
421 | * read the message at the start of the buffer. | |
422 | */ | |
423 | if (!msg->len) | |
62e32ac3 | 424 | return (struct printk_log *)log_buf; |
7ff9554b KS |
425 | return msg; |
426 | } | |
427 | ||
428 | /* get next record; idx must point to valid msg */ | |
429 | static u32 log_next(u32 idx) | |
430 | { | |
62e32ac3 | 431 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
432 | |
433 | /* length == 0 indicates the end of the buffer; wrap */ | |
434 | /* | |
435 | * A length == 0 record is the end of buffer marker. Wrap around and | |
436 | * read the message at the start of the buffer as *this* one, and | |
437 | * return the one after that. | |
438 | */ | |
439 | if (!msg->len) { | |
62e32ac3 | 440 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
441 | return msg->len; |
442 | } | |
443 | return idx + msg->len; | |
444 | } | |
445 | ||
f40e4b9f PM |
446 | /* |
447 | * Check whether there is enough free space for the given message. | |
448 | * | |
449 | * The same values of first_idx and next_idx mean that the buffer | |
450 | * is either empty or full. | |
451 | * | |
452 | * If the buffer is empty, we must respect the position of the indexes. | |
453 | * They cannot be reset to the beginning of the buffer. | |
454 | */ | |
455 | static int logbuf_has_space(u32 msg_size, bool empty) | |
0a581694 PM |
456 | { |
457 | u32 free; | |
458 | ||
f40e4b9f | 459 | if (log_next_idx > log_first_idx || empty) |
0a581694 PM |
460 | free = max(log_buf_len - log_next_idx, log_first_idx); |
461 | else | |
462 | free = log_first_idx - log_next_idx; | |
463 | ||
464 | /* | |
465 | * We need space also for an empty header that signalizes wrapping | |
466 | * of the buffer. | |
467 | */ | |
468 | return free >= msg_size + sizeof(struct printk_log); | |
469 | } | |
470 | ||
f40e4b9f | 471 | static int log_make_free_space(u32 msg_size) |
0a581694 | 472 | { |
f468908b ID |
473 | while (log_first_seq < log_next_seq && |
474 | !logbuf_has_space(msg_size, false)) { | |
0b90fec3 | 475 | /* drop old messages until we have enough contiguous space */ |
0a581694 PM |
476 | log_first_idx = log_next(log_first_idx); |
477 | log_first_seq++; | |
478 | } | |
f40e4b9f | 479 | |
f468908b ID |
480 | if (clear_seq < log_first_seq) { |
481 | clear_seq = log_first_seq; | |
482 | clear_idx = log_first_idx; | |
483 | } | |
484 | ||
f40e4b9f | 485 | /* sequence numbers are equal, so the log buffer is empty */ |
f468908b | 486 | if (logbuf_has_space(msg_size, log_first_seq == log_next_seq)) |
f40e4b9f PM |
487 | return 0; |
488 | ||
489 | return -ENOMEM; | |
0a581694 PM |
490 | } |
491 | ||
85c87043 PM |
492 | /* compute the message size including the padding bytes */ |
493 | static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) | |
494 | { | |
495 | u32 size; | |
496 | ||
497 | size = sizeof(struct printk_log) + text_len + dict_len; | |
498 | *pad_len = (-size) & (LOG_ALIGN - 1); | |
499 | size += *pad_len; | |
500 | ||
501 | return size; | |
502 | } | |
503 | ||
55bd53a4 PM |
504 | /* |
505 | * Define how much of the log buffer we could take at maximum. The value | |
506 | * must be greater than two. Note that only half of the buffer is available | |
507 | * when the index points to the middle. | |
508 | */ | |
509 | #define MAX_LOG_TAKE_PART 4 | |
510 | static const char trunc_msg[] = "<truncated>"; | |
511 | ||
512 | static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len, | |
513 | u16 *dict_len, u32 *pad_len) | |
514 | { | |
515 | /* | |
516 | * The message should not take the whole buffer. Otherwise, it might | |
517 | * get removed too soon. | |
518 | */ | |
519 | u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART; | |
520 | if (*text_len > max_text_len) | |
521 | *text_len = max_text_len; | |
522 | /* enable the warning message */ | |
523 | *trunc_msg_len = strlen(trunc_msg); | |
524 | /* disable the "dict" completely */ | |
525 | *dict_len = 0; | |
526 | /* compute the size again, count also the warning message */ | |
527 | return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len); | |
528 | } | |
529 | ||
7ff9554b | 530 | /* insert record into the buffer, discard old ones, update heads */ |
034633cc PM |
531 | static int log_store(int facility, int level, |
532 | enum log_flags flags, u64 ts_nsec, | |
533 | const char *dict, u16 dict_len, | |
534 | const char *text, u16 text_len) | |
7ff9554b | 535 | { |
62e32ac3 | 536 | struct printk_log *msg; |
7ff9554b | 537 | u32 size, pad_len; |
55bd53a4 | 538 | u16 trunc_msg_len = 0; |
7ff9554b KS |
539 | |
540 | /* number of '\0' padding bytes to next message */ | |
85c87043 | 541 | size = msg_used_size(text_len, dict_len, &pad_len); |
7ff9554b | 542 | |
55bd53a4 PM |
543 | if (log_make_free_space(size)) { |
544 | /* truncate the message if it is too long for empty buffer */ | |
545 | size = truncate_msg(&text_len, &trunc_msg_len, | |
546 | &dict_len, &pad_len); | |
547 | /* survive when the log buffer is too small for trunc_msg */ | |
548 | if (log_make_free_space(size)) | |
034633cc | 549 | return 0; |
55bd53a4 | 550 | } |
7ff9554b | 551 | |
39b25109 | 552 | if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) { |
7ff9554b KS |
553 | /* |
554 | * This message + an additional empty header does not fit | |
555 | * at the end of the buffer. Add an empty header with len == 0 | |
556 | * to signify a wrap around. | |
557 | */ | |
62e32ac3 | 558 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
559 | log_next_idx = 0; |
560 | } | |
561 | ||
562 | /* fill message */ | |
62e32ac3 | 563 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
564 | memcpy(log_text(msg), text, text_len); |
565 | msg->text_len = text_len; | |
55bd53a4 PM |
566 | if (trunc_msg_len) { |
567 | memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len); | |
568 | msg->text_len += trunc_msg_len; | |
569 | } | |
7ff9554b KS |
570 | memcpy(log_dict(msg), dict, dict_len); |
571 | msg->dict_len = dict_len; | |
084681d1 KS |
572 | msg->facility = facility; |
573 | msg->level = level & 7; | |
574 | msg->flags = flags & 0x1f; | |
575 | if (ts_nsec > 0) | |
576 | msg->ts_nsec = ts_nsec; | |
577 | else | |
578 | msg->ts_nsec = local_clock(); | |
7ff9554b | 579 | memset(log_dict(msg) + dict_len, 0, pad_len); |
fce6e033 | 580 | msg->len = size; |
7ff9554b KS |
581 | |
582 | /* insert message */ | |
583 | log_next_idx += msg->len; | |
584 | log_next_seq++; | |
034633cc PM |
585 | |
586 | return msg->text_len; | |
7ff9554b | 587 | } |
d59745ce | 588 | |
e99aa461 | 589 | int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); |
637241a9 KC |
590 | |
591 | static int syslog_action_restricted(int type) | |
592 | { | |
593 | if (dmesg_restrict) | |
594 | return 1; | |
595 | /* | |
596 | * Unless restricted, we allow "read all" and "get buffer size" | |
597 | * for everybody. | |
598 | */ | |
599 | return type != SYSLOG_ACTION_READ_ALL && | |
600 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
601 | } | |
602 | ||
3ea4331c | 603 | int check_syslog_permissions(int type, int source) |
637241a9 KC |
604 | { |
605 | /* | |
606 | * If this is from /proc/kmsg and we've already opened it, then we've | |
607 | * already done the capabilities checks at open time. | |
608 | */ | |
3ea4331c | 609 | if (source == SYSLOG_FROM_PROC && type != SYSLOG_ACTION_OPEN) |
d194e5d6 | 610 | goto ok; |
637241a9 KC |
611 | |
612 | if (syslog_action_restricted(type)) { | |
613 | if (capable(CAP_SYSLOG)) | |
d194e5d6 | 614 | goto ok; |
637241a9 KC |
615 | /* |
616 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
617 | * a warning. | |
618 | */ | |
619 | if (capable(CAP_SYS_ADMIN)) { | |
620 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
621 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
622 | "(deprecated).\n", | |
623 | current->comm, task_pid_nr(current)); | |
d194e5d6 | 624 | goto ok; |
637241a9 KC |
625 | } |
626 | return -EPERM; | |
627 | } | |
d194e5d6 | 628 | ok: |
637241a9 KC |
629 | return security_syslog(type); |
630 | } | |
ee1d2674 | 631 | EXPORT_SYMBOL_GPL(check_syslog_permissions); |
637241a9 | 632 | |
d43ff430 TH |
633 | static void append_char(char **pp, char *e, char c) |
634 | { | |
635 | if (*pp < e) | |
636 | *(*pp)++ = c; | |
637 | } | |
637241a9 | 638 | |
0a295e67 | 639 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
5aa068ea | 640 | struct printk_log *msg, u64 seq) |
0a295e67 TH |
641 | { |
642 | u64 ts_usec = msg->ts_nsec; | |
0a295e67 TH |
643 | |
644 | do_div(ts_usec, 1000); | |
645 | ||
0a295e67 | 646 | return scnprintf(buf, size, "%u,%llu,%llu,%c;", |
5aa068ea LT |
647 | (msg->facility << 3) | msg->level, seq, ts_usec, |
648 | msg->flags & LOG_CONT ? 'c' : '-'); | |
0a295e67 TH |
649 | } |
650 | ||
651 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
652 | char *dict, size_t dict_len, | |
653 | char *text, size_t text_len) | |
654 | { | |
655 | char *p = buf, *e = buf + size; | |
656 | size_t i; | |
657 | ||
658 | /* escape non-printable characters */ | |
659 | for (i = 0; i < text_len; i++) { | |
660 | unsigned char c = text[i]; | |
661 | ||
662 | if (c < ' ' || c >= 127 || c == '\\') | |
663 | p += scnprintf(p, e - p, "\\x%02x", c); | |
664 | else | |
665 | append_char(&p, e, c); | |
666 | } | |
667 | append_char(&p, e, '\n'); | |
668 | ||
669 | if (dict_len) { | |
670 | bool line = true; | |
671 | ||
672 | for (i = 0; i < dict_len; i++) { | |
673 | unsigned char c = dict[i]; | |
674 | ||
675 | if (line) { | |
676 | append_char(&p, e, ' '); | |
677 | line = false; | |
678 | } | |
679 | ||
680 | if (c == '\0') { | |
681 | append_char(&p, e, '\n'); | |
682 | line = true; | |
683 | continue; | |
684 | } | |
685 | ||
686 | if (c < ' ' || c >= 127 || c == '\\') { | |
687 | p += scnprintf(p, e - p, "\\x%02x", c); | |
688 | continue; | |
689 | } | |
690 | ||
691 | append_char(&p, e, c); | |
692 | } | |
693 | append_char(&p, e, '\n'); | |
694 | } | |
695 | ||
696 | return p - buf; | |
697 | } | |
698 | ||
e11fea92 KS |
699 | /* /dev/kmsg - userspace message inject/listen interface */ |
700 | struct devkmsg_user { | |
701 | u64 seq; | |
702 | u32 idx; | |
750afe7b | 703 | struct ratelimit_state rs; |
e11fea92 | 704 | struct mutex lock; |
d43ff430 | 705 | char buf[CONSOLE_EXT_LOG_MAX]; |
e11fea92 KS |
706 | }; |
707 | ||
849f3127 | 708 | static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) |
e11fea92 KS |
709 | { |
710 | char *buf, *line; | |
e11fea92 KS |
711 | int level = default_message_loglevel; |
712 | int facility = 1; /* LOG_USER */ | |
750afe7b BP |
713 | struct file *file = iocb->ki_filp; |
714 | struct devkmsg_user *user = file->private_data; | |
66ee59af | 715 | size_t len = iov_iter_count(from); |
e11fea92 KS |
716 | ssize_t ret = len; |
717 | ||
750afe7b | 718 | if (!user || len > LOG_LINE_MAX) |
e11fea92 | 719 | return -EINVAL; |
750afe7b BP |
720 | |
721 | /* Ignore when user logging is disabled. */ | |
722 | if (devkmsg_log & DEVKMSG_LOG_MASK_OFF) | |
723 | return len; | |
724 | ||
725 | /* Ratelimit when not explicitly enabled. */ | |
726 | if (!(devkmsg_log & DEVKMSG_LOG_MASK_ON)) { | |
727 | if (!___ratelimit(&user->rs, current->comm)) | |
728 | return ret; | |
729 | } | |
730 | ||
e11fea92 KS |
731 | buf = kmalloc(len+1, GFP_KERNEL); |
732 | if (buf == NULL) | |
733 | return -ENOMEM; | |
734 | ||
849f3127 | 735 | buf[len] = '\0'; |
cbbd26b8 | 736 | if (!copy_from_iter_full(buf, len, from)) { |
849f3127 AV |
737 | kfree(buf); |
738 | return -EFAULT; | |
e11fea92 KS |
739 | } |
740 | ||
741 | /* | |
742 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
743 | * the decimal value represents 32bit, the lower 3 bit are the log | |
744 | * level, the rest are the log facility. | |
745 | * | |
746 | * If no prefix or no userspace facility is specified, we | |
747 | * enforce LOG_USER, to be able to reliably distinguish | |
748 | * kernel-generated messages from userspace-injected ones. | |
749 | */ | |
750 | line = buf; | |
751 | if (line[0] == '<') { | |
752 | char *endp = NULL; | |
3824657c | 753 | unsigned int u; |
e11fea92 | 754 | |
3824657c | 755 | u = simple_strtoul(line + 1, &endp, 10); |
e11fea92 | 756 | if (endp && endp[0] == '>') { |
3824657c MK |
757 | level = LOG_LEVEL(u); |
758 | if (LOG_FACILITY(u) != 0) | |
759 | facility = LOG_FACILITY(u); | |
e11fea92 KS |
760 | endp++; |
761 | len -= endp - line; | |
762 | line = endp; | |
763 | } | |
764 | } | |
e11fea92 KS |
765 | |
766 | printk_emit(facility, level, NULL, 0, "%s", line); | |
e11fea92 KS |
767 | kfree(buf); |
768 | return ret; | |
769 | } | |
770 | ||
771 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
772 | size_t count, loff_t *ppos) | |
773 | { | |
774 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 775 | struct printk_log *msg; |
e11fea92 KS |
776 | size_t len; |
777 | ssize_t ret; | |
778 | ||
779 | if (!user) | |
780 | return -EBADF; | |
781 | ||
4a77a5a0 YL |
782 | ret = mutex_lock_interruptible(&user->lock); |
783 | if (ret) | |
784 | return ret; | |
5c53d819 | 785 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
786 | while (user->seq == log_next_seq) { |
787 | if (file->f_flags & O_NONBLOCK) { | |
788 | ret = -EAGAIN; | |
5c53d819 | 789 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
790 | goto out; |
791 | } | |
792 | ||
5c53d819 | 793 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
794 | ret = wait_event_interruptible(log_wait, |
795 | user->seq != log_next_seq); | |
796 | if (ret) | |
797 | goto out; | |
5c53d819 | 798 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
799 | } |
800 | ||
801 | if (user->seq < log_first_seq) { | |
802 | /* our last seen message is gone, return error and reset */ | |
803 | user->idx = log_first_idx; | |
804 | user->seq = log_first_seq; | |
805 | ret = -EPIPE; | |
5c53d819 | 806 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
807 | goto out; |
808 | } | |
809 | ||
810 | msg = log_from_idx(user->idx); | |
0a295e67 | 811 | len = msg_print_ext_header(user->buf, sizeof(user->buf), |
5aa068ea | 812 | msg, user->seq); |
0a295e67 TH |
813 | len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len, |
814 | log_dict(msg), msg->dict_len, | |
815 | log_text(msg), msg->text_len); | |
d39f3d77 | 816 | |
e11fea92 KS |
817 | user->idx = log_next(user->idx); |
818 | user->seq++; | |
5c53d819 | 819 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
820 | |
821 | if (len > count) { | |
822 | ret = -EINVAL; | |
823 | goto out; | |
824 | } | |
825 | ||
826 | if (copy_to_user(buf, user->buf, len)) { | |
827 | ret = -EFAULT; | |
828 | goto out; | |
829 | } | |
830 | ret = len; | |
831 | out: | |
832 | mutex_unlock(&user->lock); | |
833 | return ret; | |
834 | } | |
835 | ||
836 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
837 | { | |
838 | struct devkmsg_user *user = file->private_data; | |
839 | loff_t ret = 0; | |
840 | ||
841 | if (!user) | |
842 | return -EBADF; | |
843 | if (offset) | |
844 | return -ESPIPE; | |
845 | ||
5c53d819 | 846 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
847 | switch (whence) { |
848 | case SEEK_SET: | |
849 | /* the first record */ | |
850 | user->idx = log_first_idx; | |
851 | user->seq = log_first_seq; | |
852 | break; | |
853 | case SEEK_DATA: | |
854 | /* | |
855 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
856 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
857 | * changes no global state, and does not clear anything. | |
858 | */ | |
859 | user->idx = clear_idx; | |
860 | user->seq = clear_seq; | |
861 | break; | |
862 | case SEEK_END: | |
863 | /* after the last record */ | |
864 | user->idx = log_next_idx; | |
865 | user->seq = log_next_seq; | |
866 | break; | |
867 | default: | |
868 | ret = -EINVAL; | |
869 | } | |
5c53d819 | 870 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
871 | return ret; |
872 | } | |
873 | ||
874 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
875 | { | |
876 | struct devkmsg_user *user = file->private_data; | |
877 | int ret = 0; | |
878 | ||
879 | if (!user) | |
880 | return POLLERR|POLLNVAL; | |
881 | ||
882 | poll_wait(file, &log_wait, wait); | |
883 | ||
5c53d819 | 884 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
885 | if (user->seq < log_next_seq) { |
886 | /* return error when data has vanished underneath us */ | |
887 | if (user->seq < log_first_seq) | |
888 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
889 | else |
890 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 891 | } |
5c53d819 | 892 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
893 | |
894 | return ret; | |
895 | } | |
896 | ||
897 | static int devkmsg_open(struct inode *inode, struct file *file) | |
898 | { | |
899 | struct devkmsg_user *user; | |
900 | int err; | |
901 | ||
750afe7b BP |
902 | if (devkmsg_log & DEVKMSG_LOG_MASK_OFF) |
903 | return -EPERM; | |
e11fea92 | 904 | |
750afe7b BP |
905 | /* write-only does not need any file context */ |
906 | if ((file->f_flags & O_ACCMODE) != O_WRONLY) { | |
907 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, | |
908 | SYSLOG_FROM_READER); | |
909 | if (err) | |
910 | return err; | |
911 | } | |
e11fea92 KS |
912 | |
913 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
914 | if (!user) | |
915 | return -ENOMEM; | |
916 | ||
750afe7b BP |
917 | ratelimit_default_init(&user->rs); |
918 | ratelimit_set_flags(&user->rs, RATELIMIT_MSG_ON_RELEASE); | |
919 | ||
e11fea92 KS |
920 | mutex_init(&user->lock); |
921 | ||
5c53d819 | 922 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
923 | user->idx = log_first_idx; |
924 | user->seq = log_first_seq; | |
5c53d819 | 925 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
926 | |
927 | file->private_data = user; | |
928 | return 0; | |
929 | } | |
930 | ||
931 | static int devkmsg_release(struct inode *inode, struct file *file) | |
932 | { | |
933 | struct devkmsg_user *user = file->private_data; | |
934 | ||
935 | if (!user) | |
936 | return 0; | |
937 | ||
750afe7b BP |
938 | ratelimit_state_exit(&user->rs); |
939 | ||
e11fea92 KS |
940 | mutex_destroy(&user->lock); |
941 | kfree(user); | |
942 | return 0; | |
943 | } | |
944 | ||
945 | const struct file_operations kmsg_fops = { | |
946 | .open = devkmsg_open, | |
947 | .read = devkmsg_read, | |
849f3127 | 948 | .write_iter = devkmsg_write, |
e11fea92 KS |
949 | .llseek = devkmsg_llseek, |
950 | .poll = devkmsg_poll, | |
951 | .release = devkmsg_release, | |
952 | }; | |
953 | ||
2965faa5 | 954 | #ifdef CONFIG_KEXEC_CORE |
04d491ab | 955 | /* |
4c1ace64 | 956 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 957 | * |
4c1ace64 | 958 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
959 | * obtain access to symbols that are otherwise very difficult to locate. These |
960 | * symbols are specifically used so that utilities can access and extract the | |
961 | * dmesg log from a vmcore file after a crash. | |
962 | */ | |
963 | void log_buf_kexec_setup(void) | |
964 | { | |
965 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 966 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b | 967 | VMCOREINFO_SYMBOL(log_first_idx); |
f468908b | 968 | VMCOREINFO_SYMBOL(clear_idx); |
7ff9554b | 969 | VMCOREINFO_SYMBOL(log_next_idx); |
6791457a | 970 | /* |
62e32ac3 | 971 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
972 | * parse it and detect any changes to structure down the line. |
973 | */ | |
62e32ac3 JP |
974 | VMCOREINFO_STRUCT_SIZE(printk_log); |
975 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
976 | VMCOREINFO_OFFSET(printk_log, len); | |
977 | VMCOREINFO_OFFSET(printk_log, text_len); | |
978 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
979 | } |
980 | #endif | |
981 | ||
162a7e75 MT |
982 | /* requested log_buf_len from kernel cmdline */ |
983 | static unsigned long __initdata new_log_buf_len; | |
984 | ||
c0a318a3 LR |
985 | /* we practice scaling the ring buffer by powers of 2 */ |
986 | static void __init log_buf_len_update(unsigned size) | |
1da177e4 | 987 | { |
1da177e4 LT |
988 | if (size) |
989 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
990 | if (size > log_buf_len) |
991 | new_log_buf_len = size; | |
c0a318a3 LR |
992 | } |
993 | ||
994 | /* save requested log_buf_len since it's too early to process it */ | |
995 | static int __init log_buf_len_setup(char *str) | |
996 | { | |
997 | unsigned size = memparse(str, &str); | |
998 | ||
999 | log_buf_len_update(size); | |
162a7e75 MT |
1000 | |
1001 | return 0; | |
1da177e4 | 1002 | } |
162a7e75 MT |
1003 | early_param("log_buf_len", log_buf_len_setup); |
1004 | ||
2240a31d GU |
1005 | #ifdef CONFIG_SMP |
1006 | #define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT) | |
1007 | ||
23b2899f LR |
1008 | static void __init log_buf_add_cpu(void) |
1009 | { | |
1010 | unsigned int cpu_extra; | |
1011 | ||
1012 | /* | |
1013 | * archs should set up cpu_possible_bits properly with | |
1014 | * set_cpu_possible() after setup_arch() but just in | |
1015 | * case lets ensure this is valid. | |
1016 | */ | |
1017 | if (num_possible_cpus() == 1) | |
1018 | return; | |
1019 | ||
1020 | cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; | |
1021 | ||
1022 | /* by default this will only continue through for large > 64 CPUs */ | |
1023 | if (cpu_extra <= __LOG_BUF_LEN / 2) | |
1024 | return; | |
1025 | ||
1026 | pr_info("log_buf_len individual max cpu contribution: %d bytes\n", | |
1027 | __LOG_CPU_MAX_BUF_LEN); | |
1028 | pr_info("log_buf_len total cpu_extra contributions: %d bytes\n", | |
1029 | cpu_extra); | |
1030 | pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN); | |
1031 | ||
1032 | log_buf_len_update(cpu_extra + __LOG_BUF_LEN); | |
1033 | } | |
2240a31d GU |
1034 | #else /* !CONFIG_SMP */ |
1035 | static inline void log_buf_add_cpu(void) {} | |
1036 | #endif /* CONFIG_SMP */ | |
23b2899f | 1037 | |
162a7e75 MT |
1038 | void __init setup_log_buf(int early) |
1039 | { | |
1040 | unsigned long flags; | |
162a7e75 MT |
1041 | char *new_log_buf; |
1042 | int free; | |
1043 | ||
23b2899f LR |
1044 | if (log_buf != __log_buf) |
1045 | return; | |
1046 | ||
1047 | if (!early && !new_log_buf_len) | |
1048 | log_buf_add_cpu(); | |
1049 | ||
162a7e75 MT |
1050 | if (!new_log_buf_len) |
1051 | return; | |
1da177e4 | 1052 | |
162a7e75 | 1053 | if (early) { |
9da791df | 1054 | new_log_buf = |
70300177 | 1055 | memblock_virt_alloc(new_log_buf_len, LOG_ALIGN); |
162a7e75 | 1056 | } else { |
70300177 LR |
1057 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, |
1058 | LOG_ALIGN); | |
162a7e75 MT |
1059 | } |
1060 | ||
1061 | if (unlikely(!new_log_buf)) { | |
1062 | pr_err("log_buf_len: %ld bytes not available\n", | |
1063 | new_log_buf_len); | |
1064 | return; | |
1065 | } | |
1066 | ||
07354eb1 | 1067 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
1068 | log_buf_len = new_log_buf_len; |
1069 | log_buf = new_log_buf; | |
1070 | new_log_buf_len = 0; | |
7ff9554b KS |
1071 | free = __LOG_BUF_LEN - log_next_idx; |
1072 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 1073 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 | 1074 | |
f5405172 | 1075 | pr_info("log_buf_len: %d bytes\n", log_buf_len); |
162a7e75 MT |
1076 | pr_info("early log buf free: %d(%d%%)\n", |
1077 | free, (free * 100) / __LOG_BUF_LEN); | |
1078 | } | |
1da177e4 | 1079 | |
2fa72c8f AC |
1080 | static bool __read_mostly ignore_loglevel; |
1081 | ||
1082 | static int __init ignore_loglevel_setup(char *str) | |
1083 | { | |
d25d9fec | 1084 | ignore_loglevel = true; |
27083bac | 1085 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
1086 | |
1087 | return 0; | |
1088 | } | |
1089 | ||
1090 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
1091 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
205bd3d2 JP |
1092 | MODULE_PARM_DESC(ignore_loglevel, |
1093 | "ignore loglevel setting (prints all kernel messages to the console)"); | |
2fa72c8f | 1094 | |
cf775444 SS |
1095 | static bool suppress_message_printing(int level) |
1096 | { | |
1097 | return (level >= console_loglevel && !ignore_loglevel); | |
1098 | } | |
1099 | ||
bfe8df3d RD |
1100 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
1101 | ||
674dff65 | 1102 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 1103 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
1104 | |
1105 | static int __init boot_delay_setup(char *str) | |
1106 | { | |
1107 | unsigned long lpj; | |
bfe8df3d RD |
1108 | |
1109 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
1110 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
1111 | ||
1112 | get_option(&str, &boot_delay); | |
1113 | if (boot_delay > 10 * 1000) | |
1114 | boot_delay = 0; | |
1115 | ||
3a3b6ed2 DY |
1116 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
1117 | "HZ: %d, loops_per_msec: %llu\n", | |
1118 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 1119 | return 0; |
bfe8df3d | 1120 | } |
29e9d225 | 1121 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 1122 | |
2fa72c8f | 1123 | static void boot_delay_msec(int level) |
bfe8df3d RD |
1124 | { |
1125 | unsigned long long k; | |
1126 | unsigned long timeout; | |
1127 | ||
2fa72c8f | 1128 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
cf775444 | 1129 | || suppress_message_printing(level)) { |
bfe8df3d | 1130 | return; |
2fa72c8f | 1131 | } |
bfe8df3d | 1132 | |
3a3b6ed2 | 1133 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
1134 | |
1135 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
1136 | while (k) { | |
1137 | k--; | |
1138 | cpu_relax(); | |
1139 | /* | |
1140 | * use (volatile) jiffies to prevent | |
1141 | * compiler reduction; loop termination via jiffies | |
1142 | * is secondary and may or may not happen. | |
1143 | */ | |
1144 | if (time_after(jiffies, timeout)) | |
1145 | break; | |
1146 | touch_nmi_watchdog(); | |
1147 | } | |
1148 | } | |
1149 | #else | |
2fa72c8f | 1150 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
1151 | { |
1152 | } | |
1153 | #endif | |
1154 | ||
e99aa461 | 1155 | static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); |
7ff9554b KS |
1156 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
1157 | ||
084681d1 KS |
1158 | static size_t print_time(u64 ts, char *buf) |
1159 | { | |
1160 | unsigned long rem_nsec; | |
1161 | ||
1162 | if (!printk_time) | |
1163 | return 0; | |
1164 | ||
35dac27c RD |
1165 | rem_nsec = do_div(ts, 1000000000); |
1166 | ||
084681d1 | 1167 | if (!buf) |
35dac27c | 1168 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 1169 | |
084681d1 KS |
1170 | return sprintf(buf, "[%5lu.%06lu] ", |
1171 | (unsigned long)ts, rem_nsec / 1000); | |
1172 | } | |
1173 | ||
62e32ac3 | 1174 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 1175 | { |
3ce9a7c0 | 1176 | size_t len = 0; |
43a73a50 | 1177 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 1178 | |
3ce9a7c0 KS |
1179 | if (syslog) { |
1180 | if (buf) { | |
43a73a50 | 1181 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
1182 | } else { |
1183 | len += 3; | |
43a73a50 KS |
1184 | if (prefix > 999) |
1185 | len += 3; | |
1186 | else if (prefix > 99) | |
1187 | len += 2; | |
1188 | else if (prefix > 9) | |
3ce9a7c0 KS |
1189 | len++; |
1190 | } | |
1191 | } | |
649e6ee3 | 1192 | |
084681d1 | 1193 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 1194 | return len; |
649e6ee3 KS |
1195 | } |
1196 | ||
5aa068ea | 1197 | static size_t msg_print_text(const struct printk_log *msg, bool syslog, char *buf, size_t size) |
7ff9554b | 1198 | { |
3ce9a7c0 KS |
1199 | const char *text = log_text(msg); |
1200 | size_t text_size = msg->text_len; | |
1201 | size_t len = 0; | |
1202 | ||
1203 | do { | |
1204 | const char *next = memchr(text, '\n', text_size); | |
1205 | size_t text_len; | |
1206 | ||
1207 | if (next) { | |
1208 | text_len = next - text; | |
1209 | next++; | |
1210 | text_size -= next - text; | |
1211 | } else { | |
1212 | text_len = text_size; | |
1213 | } | |
7ff9554b | 1214 | |
3ce9a7c0 KS |
1215 | if (buf) { |
1216 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1217 | text_len + 1 >= size - len) |
3ce9a7c0 | 1218 | break; |
7ff9554b | 1219 | |
5aa068ea | 1220 | len += print_prefix(msg, syslog, buf + len); |
3ce9a7c0 KS |
1221 | memcpy(buf + len, text, text_len); |
1222 | len += text_len; | |
5aa068ea | 1223 | buf[len++] = '\n'; |
3ce9a7c0 KS |
1224 | } else { |
1225 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5aa068ea | 1226 | len += print_prefix(msg, syslog, NULL); |
5becfb1d | 1227 | len += text_len; |
5aa068ea | 1228 | len++; |
3ce9a7c0 | 1229 | } |
7ff9554b | 1230 | |
3ce9a7c0 KS |
1231 | text = next; |
1232 | } while (text); | |
7ff9554b | 1233 | |
7ff9554b KS |
1234 | return len; |
1235 | } | |
1236 | ||
1237 | static int syslog_print(char __user *buf, int size) | |
1238 | { | |
1239 | char *text; | |
62e32ac3 | 1240 | struct printk_log *msg; |
116e90b2 | 1241 | int len = 0; |
7ff9554b | 1242 | |
70498253 | 1243 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1244 | if (!text) |
1245 | return -ENOMEM; | |
1246 | ||
116e90b2 JB |
1247 | while (size > 0) { |
1248 | size_t n; | |
eb02dac9 | 1249 | size_t skip; |
116e90b2 JB |
1250 | |
1251 | raw_spin_lock_irq(&logbuf_lock); | |
1252 | if (syslog_seq < log_first_seq) { | |
1253 | /* messages are gone, move to first one */ | |
1254 | syslog_seq = log_first_seq; | |
1255 | syslog_idx = log_first_idx; | |
eb02dac9 | 1256 | syslog_partial = 0; |
116e90b2 JB |
1257 | } |
1258 | if (syslog_seq == log_next_seq) { | |
1259 | raw_spin_unlock_irq(&logbuf_lock); | |
1260 | break; | |
1261 | } | |
eb02dac9 KS |
1262 | |
1263 | skip = syslog_partial; | |
116e90b2 | 1264 | msg = log_from_idx(syslog_idx); |
5aa068ea | 1265 | n = msg_print_text(msg, true, text, LOG_LINE_MAX + PREFIX_MAX); |
eb02dac9 KS |
1266 | if (n - syslog_partial <= size) { |
1267 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1268 | syslog_idx = log_next(syslog_idx); |
1269 | syslog_seq++; | |
eb02dac9 KS |
1270 | n -= syslog_partial; |
1271 | syslog_partial = 0; | |
1272 | } else if (!len){ | |
1273 | /* partial read(), remember position */ | |
1274 | n = size; | |
1275 | syslog_partial += n; | |
116e90b2 JB |
1276 | } else |
1277 | n = 0; | |
1278 | raw_spin_unlock_irq(&logbuf_lock); | |
1279 | ||
1280 | if (!n) | |
1281 | break; | |
1282 | ||
eb02dac9 | 1283 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1284 | if (!len) |
1285 | len = -EFAULT; | |
1286 | break; | |
1287 | } | |
eb02dac9 KS |
1288 | |
1289 | len += n; | |
1290 | size -= n; | |
1291 | buf += n; | |
7ff9554b | 1292 | } |
7ff9554b KS |
1293 | |
1294 | kfree(text); | |
1295 | return len; | |
1296 | } | |
1297 | ||
1298 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1299 | { | |
1300 | char *text; | |
1301 | int len = 0; | |
1302 | ||
70498253 | 1303 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1304 | if (!text) |
1305 | return -ENOMEM; | |
1306 | ||
1307 | raw_spin_lock_irq(&logbuf_lock); | |
1308 | if (buf) { | |
1309 | u64 next_seq; | |
1310 | u64 seq; | |
1311 | u32 idx; | |
1312 | ||
7ff9554b KS |
1313 | /* |
1314 | * Find first record that fits, including all following records, | |
1315 | * into the user-provided buffer for this dump. | |
e2ae715d | 1316 | */ |
7ff9554b KS |
1317 | seq = clear_seq; |
1318 | idx = clear_idx; | |
1319 | while (seq < log_next_seq) { | |
62e32ac3 | 1320 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1321 | |
5aa068ea | 1322 | len += msg_print_text(msg, true, NULL, 0); |
7ff9554b KS |
1323 | idx = log_next(idx); |
1324 | seq++; | |
1325 | } | |
e2ae715d KS |
1326 | |
1327 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1328 | seq = clear_seq; |
1329 | idx = clear_idx; | |
1330 | while (len > size && seq < log_next_seq) { | |
62e32ac3 | 1331 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1332 | |
5aa068ea | 1333 | len -= msg_print_text(msg, true, NULL, 0); |
7ff9554b KS |
1334 | idx = log_next(idx); |
1335 | seq++; | |
1336 | } | |
1337 | ||
e2ae715d | 1338 | /* last message fitting into this dump */ |
7ff9554b KS |
1339 | next_seq = log_next_seq; |
1340 | ||
1341 | len = 0; | |
1342 | while (len >= 0 && seq < next_seq) { | |
62e32ac3 | 1343 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1344 | int textlen; |
1345 | ||
5aa068ea | 1346 | textlen = msg_print_text(msg, true, text, |
70498253 | 1347 | LOG_LINE_MAX + PREFIX_MAX); |
7ff9554b KS |
1348 | if (textlen < 0) { |
1349 | len = textlen; | |
1350 | break; | |
1351 | } | |
1352 | idx = log_next(idx); | |
1353 | seq++; | |
1354 | ||
1355 | raw_spin_unlock_irq(&logbuf_lock); | |
1356 | if (copy_to_user(buf + len, text, textlen)) | |
1357 | len = -EFAULT; | |
1358 | else | |
1359 | len += textlen; | |
1360 | raw_spin_lock_irq(&logbuf_lock); | |
1361 | ||
1362 | if (seq < log_first_seq) { | |
1363 | /* messages are gone, move to next one */ | |
1364 | seq = log_first_seq; | |
1365 | idx = log_first_idx; | |
1366 | } | |
1367 | } | |
1368 | } | |
1369 | ||
1370 | if (clear) { | |
1371 | clear_seq = log_next_seq; | |
1372 | clear_idx = log_next_idx; | |
1373 | } | |
1374 | raw_spin_unlock_irq(&logbuf_lock); | |
1375 | ||
1376 | kfree(text); | |
1377 | return len; | |
1378 | } | |
1379 | ||
3ea4331c | 1380 | int do_syslog(int type, char __user *buf, int len, int source) |
1da177e4 | 1381 | { |
7ff9554b | 1382 | bool clear = false; |
a39d4a85 | 1383 | static int saved_console_loglevel = LOGLEVEL_DEFAULT; |
ee24aebf | 1384 | int error; |
1da177e4 | 1385 | |
3ea4331c | 1386 | error = check_syslog_permissions(type, source); |
ee24aebf LT |
1387 | if (error) |
1388 | goto out; | |
12b3052c | 1389 | |
1da177e4 | 1390 | switch (type) { |
d78ca3cd | 1391 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1392 | break; |
d78ca3cd | 1393 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1394 | break; |
d78ca3cd | 1395 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1396 | error = -EINVAL; |
1397 | if (!buf || len < 0) | |
1398 | goto out; | |
1399 | error = 0; | |
1400 | if (!len) | |
1401 | goto out; | |
1402 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1403 | error = -EFAULT; | |
1404 | goto out; | |
1405 | } | |
40dc5651 | 1406 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1407 | syslog_seq != log_next_seq); |
cb424ffe | 1408 | if (error) |
1da177e4 | 1409 | goto out; |
7ff9554b | 1410 | error = syslog_print(buf, len); |
1da177e4 | 1411 | break; |
d78ca3cd KC |
1412 | /* Read/clear last kernel messages */ |
1413 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1414 | clear = true; |
1da177e4 | 1415 | /* FALL THRU */ |
d78ca3cd KC |
1416 | /* Read last kernel messages */ |
1417 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1418 | error = -EINVAL; |
1419 | if (!buf || len < 0) | |
1420 | goto out; | |
1421 | error = 0; | |
1422 | if (!len) | |
1423 | goto out; | |
1424 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1425 | error = -EFAULT; | |
1426 | goto out; | |
1427 | } | |
7ff9554b | 1428 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1429 | break; |
d78ca3cd KC |
1430 | /* Clear ring buffer */ |
1431 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1432 | syslog_print_all(NULL, 0, true); |
4661e356 | 1433 | break; |
d78ca3cd KC |
1434 | /* Disable logging to console */ |
1435 | case SYSLOG_ACTION_CONSOLE_OFF: | |
a39d4a85 | 1436 | if (saved_console_loglevel == LOGLEVEL_DEFAULT) |
1aaad49e | 1437 | saved_console_loglevel = console_loglevel; |
1da177e4 LT |
1438 | console_loglevel = minimum_console_loglevel; |
1439 | break; | |
d78ca3cd KC |
1440 | /* Enable logging to console */ |
1441 | case SYSLOG_ACTION_CONSOLE_ON: | |
a39d4a85 | 1442 | if (saved_console_loglevel != LOGLEVEL_DEFAULT) { |
1aaad49e | 1443 | console_loglevel = saved_console_loglevel; |
a39d4a85 | 1444 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1aaad49e | 1445 | } |
1da177e4 | 1446 | break; |
d78ca3cd KC |
1447 | /* Set level of messages printed to console */ |
1448 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1449 | error = -EINVAL; |
1450 | if (len < 1 || len > 8) | |
1451 | goto out; | |
1452 | if (len < minimum_console_loglevel) | |
1453 | len = minimum_console_loglevel; | |
1454 | console_loglevel = len; | |
1aaad49e | 1455 | /* Implicitly re-enable logging to console */ |
a39d4a85 | 1456 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1da177e4 LT |
1457 | error = 0; |
1458 | break; | |
d78ca3cd KC |
1459 | /* Number of chars in the log buffer */ |
1460 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1461 | raw_spin_lock_irq(&logbuf_lock); |
1462 | if (syslog_seq < log_first_seq) { | |
1463 | /* messages are gone, move to first one */ | |
1464 | syslog_seq = log_first_seq; | |
1465 | syslog_idx = log_first_idx; | |
eb02dac9 | 1466 | syslog_partial = 0; |
7ff9554b | 1467 | } |
3ea4331c | 1468 | if (source == SYSLOG_FROM_PROC) { |
7ff9554b KS |
1469 | /* |
1470 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1471 | * for pending data, not the size; return the count of | |
1472 | * records, not the length. | |
1473 | */ | |
e97e1267 | 1474 | error = log_next_seq - syslog_seq; |
7ff9554b | 1475 | } else { |
5becfb1d KS |
1476 | u64 seq = syslog_seq; |
1477 | u32 idx = syslog_idx; | |
7ff9554b KS |
1478 | |
1479 | error = 0; | |
7ff9554b | 1480 | while (seq < log_next_seq) { |
62e32ac3 | 1481 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1482 | |
5aa068ea | 1483 | error += msg_print_text(msg, true, NULL, 0); |
7ff9554b KS |
1484 | idx = log_next(idx); |
1485 | seq++; | |
1486 | } | |
eb02dac9 | 1487 | error -= syslog_partial; |
7ff9554b KS |
1488 | } |
1489 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1490 | break; |
d78ca3cd KC |
1491 | /* Size of the log buffer */ |
1492 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1493 | error = log_buf_len; |
1494 | break; | |
1495 | default: | |
1496 | error = -EINVAL; | |
1497 | break; | |
1498 | } | |
1499 | out: | |
1500 | return error; | |
1501 | } | |
1502 | ||
1e7bfb21 | 1503 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1504 | { |
637241a9 | 1505 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1506 | } |
1507 | ||
1da177e4 LT |
1508 | /* |
1509 | * Call the console drivers, asking them to write out | |
1510 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1511 | * The console_lock must be held. |
1da177e4 | 1512 | */ |
6fe29354 TH |
1513 | static void call_console_drivers(int level, |
1514 | const char *ext_text, size_t ext_len, | |
1515 | const char *text, size_t len) | |
1da177e4 | 1516 | { |
7ff9554b | 1517 | struct console *con; |
1da177e4 | 1518 | |
fc98c3c8 | 1519 | trace_console_rcuidle(text, len); |
7ff9554b | 1520 | |
7ff9554b KS |
1521 | if (!console_drivers) |
1522 | return; | |
1523 | ||
1524 | for_each_console(con) { | |
1525 | if (exclusive_console && con != exclusive_console) | |
1526 | continue; | |
1527 | if (!(con->flags & CON_ENABLED)) | |
1528 | continue; | |
1529 | if (!con->write) | |
1530 | continue; | |
1531 | if (!cpu_online(smp_processor_id()) && | |
1532 | !(con->flags & CON_ANYTIME)) | |
1533 | continue; | |
6fe29354 TH |
1534 | if (con->flags & CON_EXTENDED) |
1535 | con->write(con, ext_text, ext_len); | |
1536 | else | |
1537 | con->write(con, text, len); | |
7ff9554b | 1538 | } |
1da177e4 LT |
1539 | } |
1540 | ||
1541 | /* | |
205bd3d2 JP |
1542 | * Zap console related locks when oopsing. |
1543 | * To leave time for slow consoles to print a full oops, | |
1544 | * only zap at most once every 30 seconds. | |
1da177e4 LT |
1545 | */ |
1546 | static void zap_locks(void) | |
1547 | { | |
1548 | static unsigned long oops_timestamp; | |
1549 | ||
1550 | if (time_after_eq(jiffies, oops_timestamp) && | |
205bd3d2 | 1551 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1552 | return; |
1553 | ||
1554 | oops_timestamp = jiffies; | |
1555 | ||
94d24fc4 | 1556 | debug_locks_off(); |
1da177e4 | 1557 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1558 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1559 | /* And make sure that we print immediately */ |
5b8c4f23 | 1560 | sema_init(&console_sem, 1); |
1da177e4 LT |
1561 | } |
1562 | ||
af91322e DY |
1563 | int printk_delay_msec __read_mostly; |
1564 | ||
1565 | static inline void printk_delay(void) | |
1566 | { | |
1567 | if (unlikely(printk_delay_msec)) { | |
1568 | int m = printk_delay_msec; | |
1569 | ||
1570 | while (m--) { | |
1571 | mdelay(1); | |
1572 | touch_nmi_watchdog(); | |
1573 | } | |
1574 | } | |
1575 | } | |
1576 | ||
084681d1 KS |
1577 | /* |
1578 | * Continuation lines are buffered, and not committed to the record buffer | |
1579 | * until the line is complete, or a race forces it. The line fragments | |
1580 | * though, are printed immediately to the consoles to ensure everything has | |
1581 | * reached the console in case of a kernel crash. | |
1582 | */ | |
1583 | static struct cont { | |
1584 | char buf[LOG_LINE_MAX]; | |
1585 | size_t len; /* length == 0 means unused buffer */ | |
084681d1 KS |
1586 | struct task_struct *owner; /* task of first print*/ |
1587 | u64 ts_nsec; /* time of first print */ | |
1588 | u8 level; /* log level of first message */ | |
0b90fec3 | 1589 | u8 facility; /* log facility of first message */ |
eab07260 | 1590 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1591 | } cont; |
1592 | ||
5e467652 | 1593 | static void cont_flush(void) |
084681d1 | 1594 | { |
084681d1 KS |
1595 | if (cont.len == 0) |
1596 | return; | |
5c2992ee LT |
1597 | |
1598 | log_store(cont.facility, cont.level, cont.flags, cont.ts_nsec, | |
1599 | NULL, 0, cont.buf, cont.len); | |
1600 | cont.len = 0; | |
084681d1 KS |
1601 | } |
1602 | ||
5e467652 | 1603 | static bool cont_add(int facility, int level, enum log_flags flags, const char *text, size_t len) |
084681d1 | 1604 | { |
6fe29354 TH |
1605 | /* |
1606 | * If ext consoles are present, flush and skip in-kernel | |
1607 | * continuation. See nr_ext_console_drivers definition. Also, if | |
1608 | * the line gets too long, split it up in separate records. | |
1609 | */ | |
1610 | if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) { | |
5e467652 | 1611 | cont_flush(); |
084681d1 KS |
1612 | return false; |
1613 | } | |
1614 | ||
1615 | if (!cont.len) { | |
1616 | cont.facility = facility; | |
1617 | cont.level = level; | |
1618 | cont.owner = current; | |
1619 | cont.ts_nsec = local_clock(); | |
5e467652 | 1620 | cont.flags = flags; |
084681d1 KS |
1621 | } |
1622 | ||
1623 | memcpy(cont.buf + cont.len, text, len); | |
1624 | cont.len += len; | |
eab07260 | 1625 | |
5e467652 LT |
1626 | // The original flags come from the first line, |
1627 | // but later continuations can add a newline. | |
1628 | if (flags & LOG_NEWLINE) { | |
1629 | cont.flags |= LOG_NEWLINE; | |
1630 | cont_flush(); | |
1631 | } | |
1632 | ||
eab07260 | 1633 | if (cont.len > (sizeof(cont.buf) * 80) / 100) |
5e467652 | 1634 | cont_flush(); |
eab07260 | 1635 | |
084681d1 KS |
1636 | return true; |
1637 | } | |
1638 | ||
c362c7ff LT |
1639 | static size_t log_output(int facility, int level, enum log_flags lflags, const char *dict, size_t dictlen, char *text, size_t text_len) |
1640 | { | |
c362c7ff | 1641 | /* |
5e467652 LT |
1642 | * If an earlier line was buffered, and we're a continuation |
1643 | * write from the same process, try to add it to the buffer. | |
c362c7ff LT |
1644 | */ |
1645 | if (cont.len) { | |
5e467652 LT |
1646 | if (cont.owner == current && (lflags & LOG_CONT)) { |
1647 | if (cont_add(facility, level, lflags, text, text_len)) | |
1648 | return text_len; | |
1649 | } | |
1650 | /* Otherwise, make sure it's flushed */ | |
1651 | cont_flush(); | |
1652 | } | |
c362c7ff | 1653 | |
8835ca59 LT |
1654 | /* Skip empty continuation lines that couldn't be added - they just flush */ |
1655 | if (!text_len && (lflags & LOG_CONT)) | |
1656 | return 0; | |
1657 | ||
5e467652 LT |
1658 | /* If it doesn't end in a newline, try to buffer the current line */ |
1659 | if (!(lflags & LOG_NEWLINE)) { | |
1660 | if (cont_add(facility, level, lflags, text, text_len)) | |
c362c7ff LT |
1661 | return text_len; |
1662 | } | |
1663 | ||
5e467652 | 1664 | /* Store it in the record log */ |
c362c7ff LT |
1665 | return log_store(facility, level, lflags, 0, dict, dictlen, text, text_len); |
1666 | } | |
1667 | ||
7ff9554b KS |
1668 | asmlinkage int vprintk_emit(int facility, int level, |
1669 | const char *dict, size_t dictlen, | |
1670 | const char *fmt, va_list args) | |
1da177e4 | 1671 | { |
06b031de | 1672 | static bool recursion_bug; |
7ff9554b KS |
1673 | static char textbuf[LOG_LINE_MAX]; |
1674 | char *text = textbuf; | |
458df9fd | 1675 | size_t text_len = 0; |
5becfb1d | 1676 | enum log_flags lflags = 0; |
ac60ad74 | 1677 | unsigned long flags; |
32a76006 | 1678 | int this_cpu; |
7ff9554b | 1679 | int printed_len = 0; |
b522deab | 1680 | int nmi_message_lost; |
458df9fd | 1681 | bool in_sched = false; |
608873ca | 1682 | /* cpu currently holding logbuf_lock in this function */ |
f099755d | 1683 | static unsigned int logbuf_cpu = UINT_MAX; |
608873ca | 1684 | |
a39d4a85 JP |
1685 | if (level == LOGLEVEL_SCHED) { |
1686 | level = LOGLEVEL_DEFAULT; | |
458df9fd SR |
1687 | in_sched = true; |
1688 | } | |
1da177e4 | 1689 | |
2fa72c8f | 1690 | boot_delay_msec(level); |
af91322e | 1691 | printk_delay(); |
bfe8df3d | 1692 | |
1a9a8aef | 1693 | local_irq_save(flags); |
32a76006 IM |
1694 | this_cpu = smp_processor_id(); |
1695 | ||
1696 | /* | |
1697 | * Ouch, printk recursed into itself! | |
1698 | */ | |
7ff9554b | 1699 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1700 | /* |
1701 | * If a crash is occurring during printk() on this CPU, | |
1702 | * then try to get the crash message out but make sure | |
1703 | * we can't deadlock. Otherwise just return to avoid the | |
1704 | * recursion and return - but flag the recursion so that | |
1705 | * it can be printed at the next appropriate moment: | |
1706 | */ | |
94d24fc4 | 1707 | if (!oops_in_progress && !lockdep_recursing(current)) { |
06b031de | 1708 | recursion_bug = true; |
5874af20 JK |
1709 | local_irq_restore(flags); |
1710 | return 0; | |
32a76006 IM |
1711 | } |
1712 | zap_locks(); | |
1713 | } | |
1714 | ||
a0f1ccfd | 1715 | lockdep_off(); |
a8199371 | 1716 | /* This stops the holder of console_sem just where we want him */ |
07354eb1 | 1717 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1718 | logbuf_cpu = this_cpu; |
1da177e4 | 1719 | |
000a7d66 | 1720 | if (unlikely(recursion_bug)) { |
7ff9554b KS |
1721 | static const char recursion_msg[] = |
1722 | "BUG: recent printk recursion!"; | |
1723 | ||
06b031de | 1724 | recursion_bug = false; |
7ff9554b | 1725 | /* emit KERN_CRIT message */ |
034633cc | 1726 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
000a7d66 PP |
1727 | NULL, 0, recursion_msg, |
1728 | strlen(recursion_msg)); | |
32a76006 | 1729 | } |
1da177e4 | 1730 | |
b522deab PM |
1731 | nmi_message_lost = get_nmi_message_lost(); |
1732 | if (unlikely(nmi_message_lost)) { | |
1733 | text_len = scnprintf(textbuf, sizeof(textbuf), | |
1734 | "BAD LUCK: lost %d message(s) from NMI context!", | |
1735 | nmi_message_lost); | |
1736 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, | |
1737 | NULL, 0, textbuf, text_len); | |
1738 | } | |
1739 | ||
7ff9554b KS |
1740 | /* |
1741 | * The printf needs to come first; we need the syslog | |
1742 | * prefix which might be passed-in as a parameter. | |
1743 | */ | |
98e35f58 | 1744 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1745 | |
7ff9554b | 1746 | /* mark and strip a trailing newline */ |
c313af14 KS |
1747 | if (text_len && text[text_len-1] == '\n') { |
1748 | text_len--; | |
5becfb1d | 1749 | lflags |= LOG_NEWLINE; |
7ff9554b | 1750 | } |
9d90c8d9 | 1751 | |
088a52aa JP |
1752 | /* strip kernel syslog prefix and extract log level or control flags */ |
1753 | if (facility == 0) { | |
4bcc595c | 1754 | int kern_level; |
088a52aa | 1755 | |
4bcc595c | 1756 | while ((kern_level = printk_get_level(text)) != 0) { |
088a52aa JP |
1757 | switch (kern_level) { |
1758 | case '0' ... '7': | |
a39d4a85 | 1759 | if (level == LOGLEVEL_DEFAULT) |
088a52aa | 1760 | level = kern_level - '0'; |
a39d4a85 | 1761 | /* fallthrough */ |
088a52aa JP |
1762 | case 'd': /* KERN_DEFAULT */ |
1763 | lflags |= LOG_PREFIX; | |
4bcc595c LT |
1764 | break; |
1765 | case 'c': /* KERN_CONT */ | |
1766 | lflags |= LOG_CONT; | |
088a52aa | 1767 | } |
4bcc595c LT |
1768 | |
1769 | text_len -= 2; | |
1770 | text += 2; | |
5fd29d6c LT |
1771 | } |
1772 | } | |
1773 | ||
a39d4a85 | 1774 | if (level == LOGLEVEL_DEFAULT) |
c313af14 | 1775 | level = default_message_loglevel; |
9d90c8d9 | 1776 | |
5becfb1d KS |
1777 | if (dict) |
1778 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1779 | |
c362c7ff | 1780 | printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len); |
1da177e4 | 1781 | |
608873ca JK |
1782 | logbuf_cpu = UINT_MAX; |
1783 | raw_spin_unlock(&logbuf_lock); | |
5874af20 JK |
1784 | lockdep_on(); |
1785 | local_irq_restore(flags); | |
939f04be | 1786 | |
458df9fd | 1787 | /* If called from the scheduler, we can not call up(). */ |
d18bbc21 | 1788 | if (!in_sched) { |
5874af20 | 1789 | lockdep_off(); |
d18bbc21 AM |
1790 | /* |
1791 | * Try to acquire and then immediately release the console | |
1792 | * semaphore. The release will print out buffers and wake up | |
1793 | * /dev/kmsg and syslog() users. | |
1794 | */ | |
a8199371 | 1795 | if (console_trylock()) |
d18bbc21 | 1796 | console_unlock(); |
5874af20 | 1797 | lockdep_on(); |
d18bbc21 | 1798 | } |
76a8ad29 | 1799 | |
1da177e4 LT |
1800 | return printed_len; |
1801 | } | |
7ff9554b KS |
1802 | EXPORT_SYMBOL(vprintk_emit); |
1803 | ||
1804 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1805 | { | |
a39d4a85 | 1806 | return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
7ff9554b | 1807 | } |
1da177e4 LT |
1808 | EXPORT_SYMBOL(vprintk); |
1809 | ||
7ff9554b KS |
1810 | asmlinkage int printk_emit(int facility, int level, |
1811 | const char *dict, size_t dictlen, | |
1812 | const char *fmt, ...) | |
1813 | { | |
1814 | va_list args; | |
1815 | int r; | |
1816 | ||
1817 | va_start(args, fmt); | |
1818 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1819 | va_end(args); | |
1820 | ||
1821 | return r; | |
1822 | } | |
1823 | EXPORT_SYMBOL(printk_emit); | |
1824 | ||
a0cba217 | 1825 | int vprintk_default(const char *fmt, va_list args) |
afdc34a3 SRRH |
1826 | { |
1827 | int r; | |
1828 | ||
1829 | #ifdef CONFIG_KGDB_KDB | |
34aaff40 PM |
1830 | /* Allow to pass printk() to kdb but avoid a recursion. */ |
1831 | if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0)) { | |
f7d4ca8b | 1832 | r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); |
afdc34a3 SRRH |
1833 | return r; |
1834 | } | |
1835 | #endif | |
a0cba217 | 1836 | r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
afdc34a3 SRRH |
1837 | |
1838 | return r; | |
1839 | } | |
1840 | EXPORT_SYMBOL_GPL(vprintk_default); | |
1841 | ||
7ff9554b KS |
1842 | /** |
1843 | * printk - print a kernel message | |
1844 | * @fmt: format string | |
1845 | * | |
1846 | * This is printk(). It can be called from any context. We want it to work. | |
1847 | * | |
1848 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1849 | * output and call the console drivers. If we fail to get the semaphore, we | |
1850 | * place the output into the log buffer and return. The current holder of | |
1851 | * the console_sem will notice the new output in console_unlock(); and will | |
1852 | * send it to the consoles before releasing the lock. | |
1853 | * | |
1854 | * One effect of this deferred printing is that code which calls printk() and | |
1855 | * then changes console_loglevel may break. This is because console_loglevel | |
1856 | * is inspected when the actual printing occurs. | |
1857 | * | |
1858 | * See also: | |
1859 | * printf(3) | |
1860 | * | |
1861 | * See the vsnprintf() documentation for format string extensions over C99. | |
1862 | */ | |
722a9f92 | 1863 | asmlinkage __visible int printk(const char *fmt, ...) |
7ff9554b KS |
1864 | { |
1865 | va_list args; | |
1866 | int r; | |
1867 | ||
7ff9554b | 1868 | va_start(args, fmt); |
a0cba217 | 1869 | r = vprintk_func(fmt, args); |
7ff9554b KS |
1870 | va_end(args); |
1871 | ||
1872 | return r; | |
1873 | } | |
1874 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1875 | |
96efedf1 | 1876 | #else /* CONFIG_PRINTK */ |
d59745ce | 1877 | |
70498253 KS |
1878 | #define LOG_LINE_MAX 0 |
1879 | #define PREFIX_MAX 0 | |
249771b8 | 1880 | |
96efedf1 KS |
1881 | static u64 syslog_seq; |
1882 | static u32 syslog_idx; | |
eab07260 KS |
1883 | static u64 console_seq; |
1884 | static u32 console_idx; | |
96efedf1 KS |
1885 | static u64 log_first_seq; |
1886 | static u32 log_first_idx; | |
1887 | static u64 log_next_seq; | |
6fe29354 TH |
1888 | static char *log_text(const struct printk_log *msg) { return NULL; } |
1889 | static char *log_dict(const struct printk_log *msg) { return NULL; } | |
62e32ac3 | 1890 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1891 | static u32 log_next(u32 idx) { return 0; } |
6fe29354 | 1892 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
5aa068ea LT |
1893 | struct printk_log *msg, |
1894 | u64 seq) { return 0; } | |
6fe29354 TH |
1895 | static ssize_t msg_print_ext_body(char *buf, size_t size, |
1896 | char *dict, size_t dict_len, | |
1897 | char *text, size_t text_len) { return 0; } | |
1898 | static void call_console_drivers(int level, | |
1899 | const char *ext_text, size_t ext_len, | |
1900 | const char *text, size_t len) {} | |
5aa068ea | 1901 | static size_t msg_print_text(const struct printk_log *msg, |
5becfb1d | 1902 | bool syslog, char *buf, size_t size) { return 0; } |
cf775444 | 1903 | static bool suppress_message_printing(int level) { return false; } |
d59745ce | 1904 | |
04b74b27 SRRH |
1905 | /* Still needs to be defined for users */ |
1906 | DEFINE_PER_CPU(printk_func_t, printk_func); | |
1907 | ||
7f3a781d | 1908 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1909 | |
d0380e6c TG |
1910 | #ifdef CONFIG_EARLY_PRINTK |
1911 | struct console *early_console; | |
1912 | ||
722a9f92 | 1913 | asmlinkage __visible void early_printk(const char *fmt, ...) |
d0380e6c TG |
1914 | { |
1915 | va_list ap; | |
1dc6244b JP |
1916 | char buf[512]; |
1917 | int n; | |
1918 | ||
1919 | if (!early_console) | |
1920 | return; | |
d0380e6c TG |
1921 | |
1922 | va_start(ap, fmt); | |
1dc6244b | 1923 | n = vscnprintf(buf, sizeof(buf), fmt, ap); |
d0380e6c | 1924 | va_end(ap); |
1dc6244b JP |
1925 | |
1926 | early_console->write(early_console, buf, n); | |
d0380e6c TG |
1927 | } |
1928 | #endif | |
1929 | ||
f7511d5f ST |
1930 | static int __add_preferred_console(char *name, int idx, char *options, |
1931 | char *brl_options) | |
1932 | { | |
1933 | struct console_cmdline *c; | |
1934 | int i; | |
1935 | ||
1936 | /* | |
1937 | * See if this tty is not yet registered, and | |
1938 | * if we have a slot free. | |
1939 | */ | |
23475408 JP |
1940 | for (i = 0, c = console_cmdline; |
1941 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1942 | i++, c++) { | |
1943 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1944 | if (!brl_options) | |
1945 | selected_console = i; | |
1946 | return 0; | |
f7511d5f | 1947 | } |
23475408 | 1948 | } |
f7511d5f ST |
1949 | if (i == MAX_CMDLINECONSOLES) |
1950 | return -E2BIG; | |
1951 | if (!brl_options) | |
1952 | selected_console = i; | |
f7511d5f ST |
1953 | strlcpy(c->name, name, sizeof(c->name)); |
1954 | c->options = options; | |
bbeddf52 JP |
1955 | braille_set_options(c, brl_options); |
1956 | ||
f7511d5f ST |
1957 | c->index = idx; |
1958 | return 0; | |
1959 | } | |
2ea1c539 | 1960 | /* |
0b90fec3 AE |
1961 | * Set up a console. Called via do_early_param() in init/main.c |
1962 | * for each "console=" parameter in the boot command line. | |
2ea1c539 JB |
1963 | */ |
1964 | static int __init console_setup(char *str) | |
1965 | { | |
0b90fec3 | 1966 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */ |
f7511d5f | 1967 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1968 | int idx; |
1969 | ||
bbeddf52 JP |
1970 | if (_braille_console_setup(&str, &brl_options)) |
1971 | return 1; | |
f7511d5f | 1972 | |
2ea1c539 JB |
1973 | /* |
1974 | * Decode str into name, index, options. | |
1975 | */ | |
1976 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1977 | strcpy(buf, "ttyS"); |
1978 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1979 | } else { |
eaa944af | 1980 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1981 | } |
eaa944af | 1982 | buf[sizeof(buf) - 1] = 0; |
249771b8 AE |
1983 | options = strchr(str, ','); |
1984 | if (options) | |
2ea1c539 JB |
1985 | *(options++) = 0; |
1986 | #ifdef __sparc__ | |
1987 | if (!strcmp(str, "ttya")) | |
eaa944af | 1988 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1989 | if (!strcmp(str, "ttyb")) |
eaa944af | 1990 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1991 | #endif |
eaa944af | 1992 | for (s = buf; *s; s++) |
249771b8 | 1993 | if (isdigit(*s) || *s == ',') |
2ea1c539 JB |
1994 | break; |
1995 | idx = simple_strtoul(s, NULL, 10); | |
1996 | *s = 0; | |
1997 | ||
f7511d5f | 1998 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1999 | console_set_on_cmdline = 1; |
2ea1c539 JB |
2000 | return 1; |
2001 | } | |
2002 | __setup("console=", console_setup); | |
2003 | ||
3c0547ba MM |
2004 | /** |
2005 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
2006 | * @name: device name |
2007 | * @idx: device index | |
2008 | * @options: options for this console | |
3c0547ba MM |
2009 | * |
2010 | * The last preferred console added will be used for kernel messages | |
2011 | * and stdin/out/err for init. Normally this is used by console_setup | |
2012 | * above to handle user-supplied console arguments; however it can also | |
2013 | * be used by arch-specific code either to override the user or more | |
2014 | * commonly to provide a default console (ie from PROM variables) when | |
2015 | * the user has not supplied one. | |
2016 | */ | |
fb445ee5 | 2017 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 2018 | { |
f7511d5f | 2019 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
2020 | } |
2021 | ||
d25d9fec | 2022 | bool console_suspend_enabled = true; |
8f4ce8c3 AS |
2023 | EXPORT_SYMBOL(console_suspend_enabled); |
2024 | ||
2025 | static int __init console_suspend_disable(char *str) | |
2026 | { | |
d25d9fec | 2027 | console_suspend_enabled = false; |
8f4ce8c3 AS |
2028 | return 1; |
2029 | } | |
2030 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
2031 | module_param_named(console_suspend, console_suspend_enabled, |
2032 | bool, S_IRUGO | S_IWUSR); | |
2033 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
2034 | " and hibernate operations"); | |
8f4ce8c3 | 2035 | |
557240b4 LT |
2036 | /** |
2037 | * suspend_console - suspend the console subsystem | |
2038 | * | |
2039 | * This disables printk() while we go into suspend states | |
2040 | */ | |
2041 | void suspend_console(void) | |
2042 | { | |
8f4ce8c3 AS |
2043 | if (!console_suspend_enabled) |
2044 | return; | |
0d63081d | 2045 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 2046 | console_lock(); |
557240b4 | 2047 | console_suspended = 1; |
bd8d7cf5 | 2048 | up_console_sem(); |
557240b4 LT |
2049 | } |
2050 | ||
2051 | void resume_console(void) | |
2052 | { | |
8f4ce8c3 AS |
2053 | if (!console_suspend_enabled) |
2054 | return; | |
bd8d7cf5 | 2055 | down_console_sem(); |
557240b4 | 2056 | console_suspended = 0; |
ac751efa | 2057 | console_unlock(); |
557240b4 LT |
2058 | } |
2059 | ||
034260d6 KC |
2060 | /** |
2061 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
90b14889 | 2062 | * @cpu: unused |
034260d6 KC |
2063 | * |
2064 | * If printk() is called from a CPU that is not online yet, the messages | |
2065 | * will be spooled but will not show up on the console. This function is | |
2066 | * called when a new CPU comes online (or fails to come up), and ensures | |
2067 | * that any such output gets printed. | |
2068 | */ | |
90b14889 SAS |
2069 | static int console_cpu_notify(unsigned int cpu) |
2070 | { | |
f97960fb | 2071 | if (!cpuhp_tasks_frozen) { |
ac751efa TH |
2072 | console_lock(); |
2073 | console_unlock(); | |
034260d6 | 2074 | } |
90b14889 | 2075 | return 0; |
034260d6 KC |
2076 | } |
2077 | ||
1da177e4 | 2078 | /** |
ac751efa | 2079 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2080 | * |
ac751efa | 2081 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2082 | * exclusive access to the console system and the console_drivers list. |
2083 | * | |
2084 | * Can sleep, returns nothing. | |
2085 | */ | |
ac751efa | 2086 | void console_lock(void) |
1da177e4 | 2087 | { |
6b898c07 DV |
2088 | might_sleep(); |
2089 | ||
bd8d7cf5 | 2090 | down_console_sem(); |
403f3075 AH |
2091 | if (console_suspended) |
2092 | return; | |
1da177e4 LT |
2093 | console_locked = 1; |
2094 | console_may_schedule = 1; | |
2095 | } | |
ac751efa | 2096 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2097 | |
ac751efa TH |
2098 | /** |
2099 | * console_trylock - try to lock the console system for exclusive use. | |
2100 | * | |
0b90fec3 AE |
2101 | * Try to acquire a lock which guarantees that the caller has exclusive |
2102 | * access to the console system and the console_drivers list. | |
ac751efa TH |
2103 | * |
2104 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2105 | */ | |
2106 | int console_trylock(void) | |
1da177e4 | 2107 | { |
bd8d7cf5 | 2108 | if (down_trylock_console_sem()) |
ac751efa | 2109 | return 0; |
403f3075 | 2110 | if (console_suspended) { |
bd8d7cf5 | 2111 | up_console_sem(); |
ac751efa | 2112 | return 0; |
403f3075 | 2113 | } |
1da177e4 | 2114 | console_locked = 1; |
6b97a20d SS |
2115 | /* |
2116 | * When PREEMPT_COUNT disabled we can't reliably detect if it's | |
2117 | * safe to schedule (e.g. calling printk while holding a spin_lock), | |
2118 | * because preempt_disable()/preempt_enable() are just barriers there | |
2119 | * and preempt_count() is always 0. | |
2120 | * | |
2121 | * RCU read sections have a separate preemption counter when | |
2122 | * PREEMPT_RCU enabled thus we must take extra care and check | |
2123 | * rcu_preempt_depth(), otherwise RCU read sections modify | |
2124 | * preempt_count(). | |
2125 | */ | |
2126 | console_may_schedule = !oops_in_progress && | |
2127 | preemptible() && | |
2128 | !rcu_preempt_depth(); | |
ac751efa | 2129 | return 1; |
1da177e4 | 2130 | } |
ac751efa | 2131 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2132 | |
2133 | int is_console_locked(void) | |
2134 | { | |
2135 | return console_locked; | |
2136 | } | |
1da177e4 | 2137 | |
a8199371 SS |
2138 | /* |
2139 | * Check if we have any console that is capable of printing while cpu is | |
2140 | * booting or shutting down. Requires console_sem. | |
2141 | */ | |
2142 | static int have_callable_console(void) | |
2143 | { | |
2144 | struct console *con; | |
2145 | ||
2146 | for_each_console(con) | |
adaf6590 SS |
2147 | if ((con->flags & CON_ENABLED) && |
2148 | (con->flags & CON_ANYTIME)) | |
a8199371 SS |
2149 | return 1; |
2150 | ||
2151 | return 0; | |
2152 | } | |
2153 | ||
2154 | /* | |
2155 | * Can we actually use the console at this time on this cpu? | |
2156 | * | |
2157 | * Console drivers may assume that per-cpu resources have been allocated. So | |
2158 | * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't | |
2159 | * call them until this CPU is officially up. | |
2160 | */ | |
2161 | static inline int can_use_console(void) | |
2162 | { | |
2163 | return cpu_online(raw_smp_processor_id()) || have_callable_console(); | |
2164 | } | |
2165 | ||
1da177e4 | 2166 | /** |
ac751efa | 2167 | * console_unlock - unlock the console system |
1da177e4 | 2168 | * |
ac751efa | 2169 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2170 | * and the console driver list. |
2171 | * | |
ac751efa TH |
2172 | * While the console_lock was held, console output may have been buffered |
2173 | * by printk(). If this is the case, console_unlock(); emits | |
2174 | * the output prior to releasing the lock. | |
1da177e4 | 2175 | * |
7f3a781d | 2176 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2177 | * |
ac751efa | 2178 | * console_unlock(); may be called from any context. |
1da177e4 | 2179 | */ |
ac751efa | 2180 | void console_unlock(void) |
1da177e4 | 2181 | { |
6fe29354 | 2182 | static char ext_text[CONSOLE_EXT_LOG_MAX]; |
70498253 | 2183 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2184 | static u64 seen_seq; |
1da177e4 | 2185 | unsigned long flags; |
7ff9554b | 2186 | bool wake_klogd = false; |
8d91f8b1 | 2187 | bool do_cond_resched, retry; |
1da177e4 | 2188 | |
557240b4 | 2189 | if (console_suspended) { |
bd8d7cf5 | 2190 | up_console_sem(); |
557240b4 LT |
2191 | return; |
2192 | } | |
78944e54 | 2193 | |
8d91f8b1 TH |
2194 | /* |
2195 | * Console drivers are called under logbuf_lock, so | |
2196 | * @console_may_schedule should be cleared before; however, we may | |
2197 | * end up dumping a lot of lines, for example, if called from | |
2198 | * console registration path, and should invoke cond_resched() | |
2199 | * between lines if allowable. Not doing so can cause a very long | |
2200 | * scheduling stall on a slow console leading to RCU stall and | |
2201 | * softlockup warnings which exacerbate the issue with more | |
2202 | * messages practically incapacitating the system. | |
2203 | */ | |
2204 | do_cond_resched = console_may_schedule; | |
78944e54 AD |
2205 | console_may_schedule = 0; |
2206 | ||
a8199371 SS |
2207 | again: |
2208 | /* | |
2209 | * We released the console_sem lock, so we need to recheck if | |
2210 | * cpu is online and (if not) is there at least one CON_ANYTIME | |
2211 | * console. | |
2212 | */ | |
2213 | if (!can_use_console()) { | |
2214 | console_locked = 0; | |
2215 | up_console_sem(); | |
2216 | return; | |
2217 | } | |
2218 | ||
7ff9554b | 2219 | for (;;) { |
62e32ac3 | 2220 | struct printk_log *msg; |
6fe29354 | 2221 | size_t ext_len = 0; |
3ce9a7c0 | 2222 | size_t len; |
7ff9554b KS |
2223 | int level; |
2224 | ||
07354eb1 | 2225 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2226 | if (seen_seq != log_next_seq) { |
2227 | wake_klogd = true; | |
2228 | seen_seq = log_next_seq; | |
2229 | } | |
2230 | ||
2231 | if (console_seq < log_first_seq) { | |
84b5ec8a WD |
2232 | len = sprintf(text, "** %u printk messages dropped ** ", |
2233 | (unsigned)(log_first_seq - console_seq)); | |
2234 | ||
7ff9554b KS |
2235 | /* messages are gone, move to first one */ |
2236 | console_seq = log_first_seq; | |
2237 | console_idx = log_first_idx; | |
84b5ec8a WD |
2238 | } else { |
2239 | len = 0; | |
7ff9554b | 2240 | } |
084681d1 | 2241 | skip: |
7ff9554b KS |
2242 | if (console_seq == log_next_seq) |
2243 | break; | |
2244 | ||
2245 | msg = log_from_idx(console_idx); | |
cf775444 | 2246 | level = msg->level; |
5c2992ee | 2247 | if (suppress_message_printing(level)) { |
084681d1 KS |
2248 | /* |
2249 | * Skip record we have buffered and already printed | |
cf775444 SS |
2250 | * directly to the console when we received it, and |
2251 | * record that has level above the console loglevel. | |
084681d1 KS |
2252 | */ |
2253 | console_idx = log_next(console_idx); | |
2254 | console_seq++; | |
2255 | goto skip; | |
2256 | } | |
649e6ee3 | 2257 | |
5aa068ea | 2258 | len += msg_print_text(msg, false, text + len, sizeof(text) - len); |
6fe29354 TH |
2259 | if (nr_ext_console_drivers) { |
2260 | ext_len = msg_print_ext_header(ext_text, | |
2261 | sizeof(ext_text), | |
5aa068ea | 2262 | msg, console_seq); |
6fe29354 TH |
2263 | ext_len += msg_print_ext_body(ext_text + ext_len, |
2264 | sizeof(ext_text) - ext_len, | |
2265 | log_dict(msg), msg->dict_len, | |
2266 | log_text(msg), msg->text_len); | |
2267 | } | |
7ff9554b KS |
2268 | console_idx = log_next(console_idx); |
2269 | console_seq++; | |
07354eb1 | 2270 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2271 | |
81d68a96 | 2272 | stop_critical_timings(); /* don't trace print latency */ |
6fe29354 | 2273 | call_console_drivers(level, ext_text, ext_len, text, len); |
81d68a96 | 2274 | start_critical_timings(); |
1da177e4 | 2275 | local_irq_restore(flags); |
8d91f8b1 TH |
2276 | |
2277 | if (do_cond_resched) | |
2278 | cond_resched(); | |
1da177e4 LT |
2279 | } |
2280 | console_locked = 0; | |
fe3d8ad3 FT |
2281 | |
2282 | /* Release the exclusive_console once it is used */ | |
2283 | if (unlikely(exclusive_console)) | |
2284 | exclusive_console = NULL; | |
2285 | ||
07354eb1 | 2286 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2287 | |
bd8d7cf5 | 2288 | up_console_sem(); |
4f2a8d3c PZ |
2289 | |
2290 | /* | |
2291 | * Someone could have filled up the buffer again, so re-check if there's | |
2292 | * something to flush. In case we cannot trylock the console_sem again, | |
2293 | * there's a new owner and the console_unlock() from them will do the | |
2294 | * flush, no worries. | |
2295 | */ | |
07354eb1 | 2296 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2297 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2298 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2299 | ||
4f2a8d3c PZ |
2300 | if (retry && console_trylock()) |
2301 | goto again; | |
2302 | ||
e3e8a75d KK |
2303 | if (wake_klogd) |
2304 | wake_up_klogd(); | |
1da177e4 | 2305 | } |
ac751efa | 2306 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2307 | |
ddad86c2 MW |
2308 | /** |
2309 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2310 | * |
2311 | * If the console code is currently allowed to sleep, and | |
2312 | * if this CPU should yield the CPU to another task, do | |
2313 | * so here. | |
2314 | * | |
ac751efa | 2315 | * Must be called within console_lock();. |
1da177e4 LT |
2316 | */ |
2317 | void __sched console_conditional_schedule(void) | |
2318 | { | |
2319 | if (console_may_schedule) | |
2320 | cond_resched(); | |
2321 | } | |
2322 | EXPORT_SYMBOL(console_conditional_schedule); | |
2323 | ||
1da177e4 LT |
2324 | void console_unblank(void) |
2325 | { | |
2326 | struct console *c; | |
2327 | ||
2328 | /* | |
2329 | * console_unblank can no longer be called in interrupt context unless | |
2330 | * oops_in_progress is set to 1.. | |
2331 | */ | |
2332 | if (oops_in_progress) { | |
bd8d7cf5 | 2333 | if (down_trylock_console_sem() != 0) |
1da177e4 LT |
2334 | return; |
2335 | } else | |
ac751efa | 2336 | console_lock(); |
1da177e4 LT |
2337 | |
2338 | console_locked = 1; | |
2339 | console_may_schedule = 0; | |
4d091611 | 2340 | for_each_console(c) |
1da177e4 LT |
2341 | if ((c->flags & CON_ENABLED) && c->unblank) |
2342 | c->unblank(); | |
ac751efa | 2343 | console_unlock(); |
1da177e4 | 2344 | } |
1da177e4 | 2345 | |
8d91f8b1 TH |
2346 | /** |
2347 | * console_flush_on_panic - flush console content on panic | |
2348 | * | |
2349 | * Immediately output all pending messages no matter what. | |
2350 | */ | |
2351 | void console_flush_on_panic(void) | |
2352 | { | |
2353 | /* | |
2354 | * If someone else is holding the console lock, trylock will fail | |
2355 | * and may_schedule may be set. Ignore and proceed to unlock so | |
2356 | * that messages are flushed out. As this can be called from any | |
2357 | * context and we don't want to get preempted while flushing, | |
2358 | * ensure may_schedule is cleared. | |
2359 | */ | |
2360 | console_trylock(); | |
2361 | console_may_schedule = 0; | |
2362 | console_unlock(); | |
2363 | } | |
2364 | ||
1da177e4 LT |
2365 | /* |
2366 | * Return the console tty driver structure and its associated index | |
2367 | */ | |
2368 | struct tty_driver *console_device(int *index) | |
2369 | { | |
2370 | struct console *c; | |
2371 | struct tty_driver *driver = NULL; | |
2372 | ||
ac751efa | 2373 | console_lock(); |
4d091611 | 2374 | for_each_console(c) { |
1da177e4 LT |
2375 | if (!c->device) |
2376 | continue; | |
2377 | driver = c->device(c, index); | |
2378 | if (driver) | |
2379 | break; | |
2380 | } | |
ac751efa | 2381 | console_unlock(); |
1da177e4 LT |
2382 | return driver; |
2383 | } | |
2384 | ||
2385 | /* | |
2386 | * Prevent further output on the passed console device so that (for example) | |
2387 | * serial drivers can disable console output before suspending a port, and can | |
2388 | * re-enable output afterwards. | |
2389 | */ | |
2390 | void console_stop(struct console *console) | |
2391 | { | |
ac751efa | 2392 | console_lock(); |
1da177e4 | 2393 | console->flags &= ~CON_ENABLED; |
ac751efa | 2394 | console_unlock(); |
1da177e4 LT |
2395 | } |
2396 | EXPORT_SYMBOL(console_stop); | |
2397 | ||
2398 | void console_start(struct console *console) | |
2399 | { | |
ac751efa | 2400 | console_lock(); |
1da177e4 | 2401 | console->flags |= CON_ENABLED; |
ac751efa | 2402 | console_unlock(); |
1da177e4 LT |
2403 | } |
2404 | EXPORT_SYMBOL(console_start); | |
2405 | ||
7bf69395 FDN |
2406 | static int __read_mostly keep_bootcon; |
2407 | ||
2408 | static int __init keep_bootcon_setup(char *str) | |
2409 | { | |
2410 | keep_bootcon = 1; | |
27083bac | 2411 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2412 | |
2413 | return 0; | |
2414 | } | |
2415 | ||
2416 | early_param("keep_bootcon", keep_bootcon_setup); | |
2417 | ||
1da177e4 LT |
2418 | /* |
2419 | * The console driver calls this routine during kernel initialization | |
2420 | * to register the console printing procedure with printk() and to | |
2421 | * print any messages that were printed by the kernel before the | |
2422 | * console driver was initialized. | |
4d091611 RG |
2423 | * |
2424 | * This can happen pretty early during the boot process (because of | |
2425 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2426 | * of what kernel features are used - they may not be initialised yet. | |
2427 | * | |
2428 | * There are two types of consoles - bootconsoles (early_printk) and | |
2429 | * "real" consoles (everything which is not a bootconsole) which are | |
2430 | * handled differently. | |
2431 | * - Any number of bootconsoles can be registered at any time. | |
2432 | * - As soon as a "real" console is registered, all bootconsoles | |
2433 | * will be unregistered automatically. | |
2434 | * - Once a "real" console is registered, any attempt to register a | |
2435 | * bootconsoles will be rejected | |
1da177e4 | 2436 | */ |
4d091611 | 2437 | void register_console(struct console *newcon) |
1da177e4 | 2438 | { |
40dc5651 | 2439 | int i; |
1da177e4 | 2440 | unsigned long flags; |
4d091611 | 2441 | struct console *bcon = NULL; |
23475408 | 2442 | struct console_cmdline *c; |
1da177e4 | 2443 | |
16cf48a6 AB |
2444 | if (console_drivers) |
2445 | for_each_console(bcon) | |
2446 | if (WARN(bcon == newcon, | |
2447 | "console '%s%d' already registered\n", | |
2448 | bcon->name, bcon->index)) | |
2449 | return; | |
2450 | ||
4d091611 RG |
2451 | /* |
2452 | * before we register a new CON_BOOT console, make sure we don't | |
2453 | * already have a valid console | |
2454 | */ | |
2455 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2456 | /* find the last or real console */ | |
2457 | for_each_console(bcon) { | |
2458 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2459 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2460 | newcon->name, newcon->index); |
2461 | return; | |
2462 | } | |
2463 | } | |
69331af7 GH |
2464 | } |
2465 | ||
4d091611 RG |
2466 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2467 | bcon = console_drivers; | |
2468 | ||
2469 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2470 | preferred_console = selected_console; |
2471 | ||
2472 | /* | |
2473 | * See if we want to use this console driver. If we | |
2474 | * didn't select a console we take the first one | |
2475 | * that registers here. | |
2476 | */ | |
c6c7d83b | 2477 | if (preferred_console < 0) { |
4d091611 RG |
2478 | if (newcon->index < 0) |
2479 | newcon->index = 0; | |
2480 | if (newcon->setup == NULL || | |
2481 | newcon->setup(newcon, NULL) == 0) { | |
2482 | newcon->flags |= CON_ENABLED; | |
2483 | if (newcon->device) { | |
2484 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2485 | preferred_console = 0; |
2486 | } | |
1da177e4 LT |
2487 | } |
2488 | } | |
2489 | ||
2490 | /* | |
2491 | * See if this console matches one we selected on | |
2492 | * the command line. | |
2493 | */ | |
23475408 JP |
2494 | for (i = 0, c = console_cmdline; |
2495 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
2496 | i++, c++) { | |
c7cef0a8 PH |
2497 | if (!newcon->match || |
2498 | newcon->match(newcon, c->name, c->index, c->options) != 0) { | |
2499 | /* default matching */ | |
2500 | BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); | |
2501 | if (strcmp(c->name, newcon->name) != 0) | |
2502 | continue; | |
2503 | if (newcon->index >= 0 && | |
2504 | newcon->index != c->index) | |
2505 | continue; | |
2506 | if (newcon->index < 0) | |
2507 | newcon->index = c->index; | |
bbeddf52 | 2508 | |
c7cef0a8 PH |
2509 | if (_braille_register_console(newcon, c)) |
2510 | return; | |
2511 | ||
2512 | if (newcon->setup && | |
2513 | newcon->setup(newcon, c->options) != 0) | |
2514 | break; | |
2515 | } | |
bbeddf52 | 2516 | |
4d091611 | 2517 | newcon->flags |= CON_ENABLED; |
ab4af03a | 2518 | if (i == selected_console) { |
4d091611 | 2519 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2520 | preferred_console = selected_console; |
2521 | } | |
1da177e4 LT |
2522 | break; |
2523 | } | |
2524 | ||
4d091611 | 2525 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2526 | return; |
2527 | ||
8259cf43 RG |
2528 | /* |
2529 | * If we have a bootconsole, and are switching to a real console, | |
2530 | * don't print everything out again, since when the boot console, and | |
2531 | * the real console are the same physical device, it's annoying to | |
2532 | * see the beginning boot messages twice | |
2533 | */ | |
2534 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2535 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2536 | |
2537 | /* | |
2538 | * Put this console in the list - keep the | |
2539 | * preferred driver at the head of the list. | |
2540 | */ | |
ac751efa | 2541 | console_lock(); |
4d091611 RG |
2542 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2543 | newcon->next = console_drivers; | |
2544 | console_drivers = newcon; | |
2545 | if (newcon->next) | |
2546 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2547 | } else { |
4d091611 RG |
2548 | newcon->next = console_drivers->next; |
2549 | console_drivers->next = newcon; | |
1da177e4 | 2550 | } |
6fe29354 TH |
2551 | |
2552 | if (newcon->flags & CON_EXTENDED) | |
2553 | if (!nr_ext_console_drivers++) | |
2554 | pr_info("printk: continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n"); | |
2555 | ||
4d091611 | 2556 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2557 | /* |
ac751efa | 2558 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2559 | * for us. |
2560 | */ | |
07354eb1 | 2561 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2562 | console_seq = syslog_seq; |
2563 | console_idx = syslog_idx; | |
07354eb1 | 2564 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2565 | /* |
2566 | * We're about to replay the log buffer. Only do this to the | |
2567 | * just-registered console to avoid excessive message spam to | |
2568 | * the already-registered consoles. | |
2569 | */ | |
2570 | exclusive_console = newcon; | |
1da177e4 | 2571 | } |
ac751efa | 2572 | console_unlock(); |
fbc92a34 | 2573 | console_sysfs_notify(); |
8259cf43 RG |
2574 | |
2575 | /* | |
2576 | * By unregistering the bootconsoles after we enable the real console | |
2577 | * we get the "console xxx enabled" message on all the consoles - | |
2578 | * boot consoles, real consoles, etc - this is to ensure that end | |
2579 | * users know there might be something in the kernel's log buffer that | |
2580 | * went to the bootconsole (that they do not see on the real console) | |
2581 | */ | |
27083bac | 2582 | pr_info("%sconsole [%s%d] enabled\n", |
6b802394 KC |
2583 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
2584 | newcon->name, newcon->index); | |
7bf69395 FDN |
2585 | if (bcon && |
2586 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2587 | !keep_bootcon) { | |
6b802394 KC |
2588 | /* We need to iterate through all boot consoles, to make |
2589 | * sure we print everything out, before we unregister them. | |
8259cf43 | 2590 | */ |
8259cf43 RG |
2591 | for_each_console(bcon) |
2592 | if (bcon->flags & CON_BOOT) | |
2593 | unregister_console(bcon); | |
8259cf43 | 2594 | } |
1da177e4 LT |
2595 | } |
2596 | EXPORT_SYMBOL(register_console); | |
2597 | ||
40dc5651 | 2598 | int unregister_console(struct console *console) |
1da177e4 | 2599 | { |
40dc5651 | 2600 | struct console *a, *b; |
bbeddf52 | 2601 | int res; |
1da177e4 | 2602 | |
27083bac | 2603 | pr_info("%sconsole [%s%d] disabled\n", |
6b802394 KC |
2604 | (console->flags & CON_BOOT) ? "boot" : "" , |
2605 | console->name, console->index); | |
2606 | ||
bbeddf52 JP |
2607 | res = _braille_unregister_console(console); |
2608 | if (res) | |
2609 | return res; | |
f7511d5f | 2610 | |
bbeddf52 | 2611 | res = 1; |
ac751efa | 2612 | console_lock(); |
1da177e4 LT |
2613 | if (console_drivers == console) { |
2614 | console_drivers=console->next; | |
2615 | res = 0; | |
e9b15b54 | 2616 | } else if (console_drivers) { |
1da177e4 LT |
2617 | for (a=console_drivers->next, b=console_drivers ; |
2618 | a; b=a, a=b->next) { | |
2619 | if (a == console) { | |
2620 | b->next = a->next; | |
2621 | res = 0; | |
2622 | break; | |
40dc5651 | 2623 | } |
1da177e4 LT |
2624 | } |
2625 | } | |
40dc5651 | 2626 | |
6fe29354 TH |
2627 | if (!res && (console->flags & CON_EXTENDED)) |
2628 | nr_ext_console_drivers--; | |
2629 | ||
69331af7 | 2630 | /* |
ab4af03a GE |
2631 | * If this isn't the last console and it has CON_CONSDEV set, we |
2632 | * need to set it on the next preferred console. | |
1da177e4 | 2633 | */ |
69331af7 | 2634 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2635 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2636 | |
7fa21dd8 | 2637 | console->flags &= ~CON_ENABLED; |
ac751efa | 2638 | console_unlock(); |
fbc92a34 | 2639 | console_sysfs_notify(); |
1da177e4 LT |
2640 | return res; |
2641 | } | |
2642 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2643 | |
81cc26f2 TR |
2644 | /* |
2645 | * Some boot consoles access data that is in the init section and which will | |
2646 | * be discarded after the initcalls have been run. To make sure that no code | |
2647 | * will access this data, unregister the boot consoles in a late initcall. | |
2648 | * | |
2649 | * If for some reason, such as deferred probe or the driver being a loadable | |
2650 | * module, the real console hasn't registered yet at this point, there will | |
2651 | * be a brief interval in which no messages are logged to the console, which | |
2652 | * makes it difficult to diagnose problems that occur during this time. | |
2653 | * | |
2654 | * To mitigate this problem somewhat, only unregister consoles whose memory | |
2655 | * intersects with the init section. Note that code exists elsewhere to get | |
2656 | * rid of the boot console as soon as the proper console shows up, so there | |
2657 | * won't be side-effects from postponing the removal. | |
2658 | */ | |
034260d6 | 2659 | static int __init printk_late_init(void) |
0c5564bd | 2660 | { |
4d091611 | 2661 | struct console *con; |
90b14889 | 2662 | int ret; |
4d091611 RG |
2663 | |
2664 | for_each_console(con) { | |
4c30c6f5 | 2665 | if (!keep_bootcon && con->flags & CON_BOOT) { |
81cc26f2 TR |
2666 | /* |
2667 | * Make sure to unregister boot consoles whose data | |
2668 | * resides in the init section before the init section | |
2669 | * is discarded. Boot consoles whose data will stick | |
2670 | * around will automatically be unregistered when the | |
2671 | * proper console replaces them. | |
2672 | */ | |
2673 | if (init_section_intersects(con, sizeof(*con))) | |
2674 | unregister_console(con); | |
cb00e99c | 2675 | } |
0c5564bd | 2676 | } |
90b14889 SAS |
2677 | ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, |
2678 | console_cpu_notify); | |
2679 | WARN_ON(ret < 0); | |
2680 | ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online", | |
2681 | console_cpu_notify, NULL); | |
2682 | WARN_ON(ret < 0); | |
0c5564bd RG |
2683 | return 0; |
2684 | } | |
034260d6 | 2685 | late_initcall(printk_late_init); |
0c5564bd | 2686 | |
7ef3d2fd | 2687 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2688 | /* |
2689 | * Delayed printk version, for scheduler-internal messages: | |
2690 | */ | |
dc72c32e | 2691 | #define PRINTK_PENDING_WAKEUP 0x01 |
458df9fd | 2692 | #define PRINTK_PENDING_OUTPUT 0x02 |
dc72c32e FW |
2693 | |
2694 | static DEFINE_PER_CPU(int, printk_pending); | |
dc72c32e FW |
2695 | |
2696 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2697 | { | |
2698 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2699 | ||
458df9fd SR |
2700 | if (pending & PRINTK_PENDING_OUTPUT) { |
2701 | /* If trylock fails, someone else is doing the printing */ | |
2702 | if (console_trylock()) | |
2703 | console_unlock(); | |
dc72c32e FW |
2704 | } |
2705 | ||
2706 | if (pending & PRINTK_PENDING_WAKEUP) | |
2707 | wake_up_interruptible(&log_wait); | |
2708 | } | |
2709 | ||
2710 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2711 | .func = wake_up_klogd_work_func, | |
2712 | .flags = IRQ_WORK_LAZY, | |
2713 | }; | |
2714 | ||
2715 | void wake_up_klogd(void) | |
2716 | { | |
2717 | preempt_disable(); | |
2718 | if (waitqueue_active(&log_wait)) { | |
2719 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
bb964a92 | 2720 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
dc72c32e FW |
2721 | } |
2722 | preempt_enable(); | |
2723 | } | |
717115e1 | 2724 | |
aac74dc4 | 2725 | int printk_deferred(const char *fmt, ...) |
600e1458 | 2726 | { |
600e1458 | 2727 | va_list args; |
600e1458 PZ |
2728 | int r; |
2729 | ||
81954606 | 2730 | preempt_disable(); |
600e1458 | 2731 | va_start(args, fmt); |
a39d4a85 | 2732 | r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); |
600e1458 PZ |
2733 | va_end(args); |
2734 | ||
458df9fd | 2735 | __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); |
bb964a92 | 2736 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
81954606 | 2737 | preempt_enable(); |
600e1458 PZ |
2738 | |
2739 | return r; | |
2740 | } | |
2741 | ||
1da177e4 LT |
2742 | /* |
2743 | * printk rate limiting, lifted from the networking subsystem. | |
2744 | * | |
641de9d8 UKK |
2745 | * This enforces a rate limit: not more than 10 kernel messages |
2746 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2747 | */ |
641de9d8 UKK |
2748 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2749 | ||
5c828713 | 2750 | int __printk_ratelimit(const char *func) |
1da177e4 | 2751 | { |
5c828713 | 2752 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2753 | } |
5c828713 | 2754 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2755 | |
2756 | /** | |
2757 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2758 | * @caller_jiffies: pointer to caller's state | |
2759 | * @interval_msecs: minimum interval between prints | |
2760 | * | |
2761 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2762 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2763 | * returned true. | |
2764 | */ | |
2765 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2766 | unsigned int interval_msecs) | |
2767 | { | |
249771b8 AE |
2768 | unsigned long elapsed = jiffies - *caller_jiffies; |
2769 | ||
2770 | if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) | |
2771 | return false; | |
2772 | ||
2773 | *caller_jiffies = jiffies; | |
2774 | return true; | |
f46c4833 AM |
2775 | } |
2776 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2777 | |
2778 | static DEFINE_SPINLOCK(dump_list_lock); | |
2779 | static LIST_HEAD(dump_list); | |
2780 | ||
2781 | /** | |
2782 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2783 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2784 | * |
2785 | * Adds a kernel log dumper to the system. The dump callback in the | |
2786 | * structure will be called when the kernel oopses or panics and must be | |
2787 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2788 | */ | |
2789 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2790 | { | |
2791 | unsigned long flags; | |
2792 | int err = -EBUSY; | |
2793 | ||
2794 | /* The dump callback needs to be set */ | |
2795 | if (!dumper->dump) | |
2796 | return -EINVAL; | |
2797 | ||
2798 | spin_lock_irqsave(&dump_list_lock, flags); | |
2799 | /* Don't allow registering multiple times */ | |
2800 | if (!dumper->registered) { | |
2801 | dumper->registered = 1; | |
fb842b00 | 2802 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2803 | err = 0; |
2804 | } | |
2805 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2806 | ||
2807 | return err; | |
2808 | } | |
2809 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2810 | ||
2811 | /** | |
2812 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2813 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2814 | * |
2815 | * Removes a dump device from the system. Returns zero on success and | |
2816 | * %-EINVAL otherwise. | |
2817 | */ | |
2818 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2819 | { | |
2820 | unsigned long flags; | |
2821 | int err = -EINVAL; | |
2822 | ||
2823 | spin_lock_irqsave(&dump_list_lock, flags); | |
2824 | if (dumper->registered) { | |
2825 | dumper->registered = 0; | |
fb842b00 | 2826 | list_del_rcu(&dumper->list); |
456b565c SK |
2827 | err = 0; |
2828 | } | |
2829 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2830 | synchronize_rcu(); |
456b565c SK |
2831 | |
2832 | return err; | |
2833 | } | |
2834 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2835 | ||
7ff9554b KS |
2836 | static bool always_kmsg_dump; |
2837 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2838 | ||
456b565c SK |
2839 | /** |
2840 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2841 | * @reason: the reason (oops, panic etc) for dumping | |
2842 | * | |
e2ae715d KS |
2843 | * Call each of the registered dumper's dump() callback, which can |
2844 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2845 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2846 | */ |
2847 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2848 | { | |
456b565c | 2849 | struct kmsg_dumper *dumper; |
456b565c SK |
2850 | unsigned long flags; |
2851 | ||
c22ab332 MG |
2852 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2853 | return; | |
2854 | ||
e2ae715d KS |
2855 | rcu_read_lock(); |
2856 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2857 | if (dumper->max_reason && reason > dumper->max_reason) | |
2858 | continue; | |
2859 | ||
2860 | /* initialize iterator with data about the stored records */ | |
2861 | dumper->active = true; | |
2862 | ||
2863 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2864 | dumper->cur_seq = clear_seq; | |
2865 | dumper->cur_idx = clear_idx; | |
2866 | dumper->next_seq = log_next_seq; | |
2867 | dumper->next_idx = log_next_idx; | |
2868 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2869 | ||
2870 | /* invoke dumper which will iterate over records */ | |
2871 | dumper->dump(dumper, reason); | |
2872 | ||
2873 | /* reset iterator */ | |
2874 | dumper->active = false; | |
2875 | } | |
2876 | rcu_read_unlock(); | |
2877 | } | |
2878 | ||
2879 | /** | |
533827c9 | 2880 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2881 | * @dumper: registered kmsg dumper |
2882 | * @syslog: include the "<4>" prefixes | |
2883 | * @line: buffer to copy the line to | |
2884 | * @size: maximum size of the buffer | |
2885 | * @len: length of line placed into buffer | |
2886 | * | |
2887 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2888 | * record, and copy one record into the provided buffer. | |
2889 | * | |
2890 | * Consecutive calls will return the next available record moving | |
2891 | * towards the end of the buffer with the youngest messages. | |
2892 | * | |
2893 | * A return value of FALSE indicates that there are no more records to | |
2894 | * read. | |
533827c9 AV |
2895 | * |
2896 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2897 | */ |
533827c9 AV |
2898 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2899 | char *line, size_t size, size_t *len) | |
e2ae715d | 2900 | { |
62e32ac3 | 2901 | struct printk_log *msg; |
e2ae715d KS |
2902 | size_t l = 0; |
2903 | bool ret = false; | |
2904 | ||
2905 | if (!dumper->active) | |
2906 | goto out; | |
7ff9554b | 2907 | |
e2ae715d KS |
2908 | if (dumper->cur_seq < log_first_seq) { |
2909 | /* messages are gone, move to first available one */ | |
2910 | dumper->cur_seq = log_first_seq; | |
2911 | dumper->cur_idx = log_first_idx; | |
2912 | } | |
456b565c | 2913 | |
e2ae715d | 2914 | /* last entry */ |
533827c9 | 2915 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2916 | goto out; |
456b565c | 2917 | |
e2ae715d | 2918 | msg = log_from_idx(dumper->cur_idx); |
5aa068ea | 2919 | l = msg_print_text(msg, syslog, line, size); |
e2ae715d KS |
2920 | |
2921 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2922 | dumper->cur_seq++; | |
2923 | ret = true; | |
e2ae715d KS |
2924 | out: |
2925 | if (len) | |
2926 | *len = l; | |
2927 | return ret; | |
2928 | } | |
533827c9 AV |
2929 | |
2930 | /** | |
2931 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2932 | * @dumper: registered kmsg dumper | |
2933 | * @syslog: include the "<4>" prefixes | |
2934 | * @line: buffer to copy the line to | |
2935 | * @size: maximum size of the buffer | |
2936 | * @len: length of line placed into buffer | |
2937 | * | |
2938 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2939 | * record, and copy one record into the provided buffer. | |
2940 | * | |
2941 | * Consecutive calls will return the next available record moving | |
2942 | * towards the end of the buffer with the youngest messages. | |
2943 | * | |
2944 | * A return value of FALSE indicates that there are no more records to | |
2945 | * read. | |
2946 | */ | |
2947 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2948 | char *line, size_t size, size_t *len) | |
2949 | { | |
2950 | unsigned long flags; | |
2951 | bool ret; | |
2952 | ||
2953 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2954 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2955 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2956 | ||
2957 | return ret; | |
2958 | } | |
e2ae715d KS |
2959 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2960 | ||
2961 | /** | |
2962 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2963 | * @dumper: registered kmsg dumper | |
2964 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2965 | * @buf: buffer to copy the line to |
e2ae715d KS |
2966 | * @size: maximum size of the buffer |
2967 | * @len: length of line placed into buffer | |
2968 | * | |
2969 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2970 | * with as many of the the *youngest* kmsg records that fit into it. | |
2971 | * If the buffer is large enough, all available kmsg records will be | |
2972 | * copied with a single call. | |
2973 | * | |
2974 | * Consecutive calls will fill the buffer with the next block of | |
2975 | * available older records, not including the earlier retrieved ones. | |
2976 | * | |
2977 | * A return value of FALSE indicates that there are no more records to | |
2978 | * read. | |
2979 | */ | |
2980 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2981 | char *buf, size_t size, size_t *len) | |
2982 | { | |
2983 | unsigned long flags; | |
2984 | u64 seq; | |
2985 | u32 idx; | |
2986 | u64 next_seq; | |
2987 | u32 next_idx; | |
2988 | size_t l = 0; | |
2989 | bool ret = false; | |
2990 | ||
2991 | if (!dumper->active) | |
2992 | goto out; | |
2993 | ||
2994 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2995 | if (dumper->cur_seq < log_first_seq) { | |
2996 | /* messages are gone, move to first available one */ | |
2997 | dumper->cur_seq = log_first_seq; | |
2998 | dumper->cur_idx = log_first_idx; | |
2999 | } | |
3000 | ||
3001 | /* last entry */ | |
3002 | if (dumper->cur_seq >= dumper->next_seq) { | |
3003 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
3004 | goto out; | |
3005 | } | |
3006 | ||
3007 | /* calculate length of entire buffer */ | |
3008 | seq = dumper->cur_seq; | |
3009 | idx = dumper->cur_idx; | |
3010 | while (seq < dumper->next_seq) { | |
62e32ac3 | 3011 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3012 | |
5aa068ea | 3013 | l += msg_print_text(msg, true, NULL, 0); |
e2ae715d KS |
3014 | idx = log_next(idx); |
3015 | seq++; | |
3016 | } | |
3017 | ||
3018 | /* move first record forward until length fits into the buffer */ | |
3019 | seq = dumper->cur_seq; | |
3020 | idx = dumper->cur_idx; | |
3021 | while (l > size && seq < dumper->next_seq) { | |
62e32ac3 | 3022 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 3023 | |
5aa068ea | 3024 | l -= msg_print_text(msg, true, NULL, 0); |
e2ae715d KS |
3025 | idx = log_next(idx); |
3026 | seq++; | |
456b565c | 3027 | } |
e2ae715d KS |
3028 | |
3029 | /* last message in next interation */ | |
3030 | next_seq = seq; | |
3031 | next_idx = idx; | |
3032 | ||
3033 | l = 0; | |
3034 | while (seq < dumper->next_seq) { | |
62e32ac3 | 3035 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3036 | |
5aa068ea | 3037 | l += msg_print_text(msg, syslog, buf + l, size - l); |
e2ae715d KS |
3038 | idx = log_next(idx); |
3039 | seq++; | |
3040 | } | |
3041 | ||
3042 | dumper->next_seq = next_seq; | |
3043 | dumper->next_idx = next_idx; | |
3044 | ret = true; | |
7ff9554b | 3045 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
3046 | out: |
3047 | if (len) | |
3048 | *len = l; | |
3049 | return ret; | |
3050 | } | |
3051 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 3052 | |
533827c9 AV |
3053 | /** |
3054 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
3055 | * @dumper: registered kmsg dumper | |
3056 | * | |
3057 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3058 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3059 | * times within the same dumper.dump() callback. | |
3060 | * | |
3061 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
3062 | */ | |
3063 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
3064 | { | |
3065 | dumper->cur_seq = clear_seq; | |
3066 | dumper->cur_idx = clear_idx; | |
3067 | dumper->next_seq = log_next_seq; | |
3068 | dumper->next_idx = log_next_idx; | |
3069 | } | |
3070 | ||
e2ae715d KS |
3071 | /** |
3072 | * kmsg_dump_rewind - reset the interator | |
3073 | * @dumper: registered kmsg dumper | |
3074 | * | |
3075 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3076 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3077 | * times within the same dumper.dump() callback. | |
3078 | */ | |
3079 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
3080 | { | |
3081 | unsigned long flags; | |
3082 | ||
3083 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 3084 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 3085 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 3086 | } |
e2ae715d | 3087 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 3088 | |
98e5e1bf TH |
3089 | static char dump_stack_arch_desc_str[128]; |
3090 | ||
3091 | /** | |
3092 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
3093 | * @fmt: printf-style format string | |
3094 | * @...: arguments for the format string | |
3095 | * | |
3096 | * The configured string will be printed right after utsname during task | |
3097 | * dumps. Usually used to add arch-specific system identifiers. If an | |
3098 | * arch wants to make use of such an ID string, it should initialize this | |
3099 | * as soon as possible during boot. | |
3100 | */ | |
3101 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
3102 | { | |
3103 | va_list args; | |
3104 | ||
3105 | va_start(args, fmt); | |
3106 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
3107 | fmt, args); | |
3108 | va_end(args); | |
3109 | } | |
3110 | ||
196779b9 TH |
3111 | /** |
3112 | * dump_stack_print_info - print generic debug info for dump_stack() | |
3113 | * @log_lvl: log level | |
3114 | * | |
3115 | * Arch-specific dump_stack() implementations can use this function to | |
3116 | * print out the same debug information as the generic dump_stack(). | |
3117 | */ | |
3118 | void dump_stack_print_info(const char *log_lvl) | |
3119 | { | |
3120 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
3121 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
3122 | print_tainted(), init_utsname()->release, | |
3123 | (int)strcspn(init_utsname()->version, " "), | |
3124 | init_utsname()->version); | |
98e5e1bf TH |
3125 | |
3126 | if (dump_stack_arch_desc_str[0] != '\0') | |
3127 | printk("%sHardware name: %s\n", | |
3128 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
3129 | |
3130 | print_worker_info(log_lvl, current); | |
196779b9 TH |
3131 | } |
3132 | ||
a43cb95d TH |
3133 | /** |
3134 | * show_regs_print_info - print generic debug info for show_regs() | |
3135 | * @log_lvl: log level | |
3136 | * | |
3137 | * show_regs() implementations can use this function to print out generic | |
3138 | * debug information. | |
3139 | */ | |
3140 | void show_regs_print_info(const char *log_lvl) | |
3141 | { | |
3142 | dump_stack_print_info(log_lvl); | |
3143 | ||
8b70ca65 AL |
3144 | printk("%stask: %p task.stack: %p\n", |
3145 | log_lvl, current, task_stack_page(current)); | |
a43cb95d TH |
3146 | } |
3147 | ||
7ef3d2fd | 3148 | #endif |