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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> |
692f66f2 | 35 | #include <linux/crash_core.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> |
e6017571 | 48 | #include <linux/sched/clock.h> |
b17b0153 | 49 | #include <linux/sched/debug.h> |
68db0cf1 | 50 | #include <linux/sched/task_stack.h> |
1da177e4 | 51 | |
7c0f6ba6 | 52 | #include <linux/uaccess.h> |
40a7d9f5 | 53 | #include <asm/sections.h> |
1da177e4 | 54 | |
95100358 JB |
55 | #define CREATE_TRACE_POINTS |
56 | #include <trace/events/printk.h> | |
57 | ||
d197c43d | 58 | #include "console_cmdline.h" |
bbeddf52 | 59 | #include "braille.h" |
42a0bb3f | 60 | #include "internal.h" |
d197c43d | 61 | |
1da177e4 | 62 | int console_printk[4] = { |
a8fe19eb | 63 | CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */ |
42a9dc0b | 64 | MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */ |
a8fe19eb BP |
65 | CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */ |
66 | CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */ | |
1da177e4 LT |
67 | }; |
68 | ||
1da177e4 | 69 | /* |
0bbfb7c2 | 70 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
71 | * their unblank() callback or not. So let's export it. |
72 | */ | |
73 | int oops_in_progress; | |
74 | EXPORT_SYMBOL(oops_in_progress); | |
75 | ||
76 | /* | |
77 | * console_sem protects the console_drivers list, and also | |
78 | * provides serialisation for access to the entire console | |
79 | * driver system. | |
80 | */ | |
5b8c4f23 | 81 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 82 | struct console *console_drivers; |
a29d1cfe IM |
83 | EXPORT_SYMBOL_GPL(console_drivers); |
84 | ||
daee7797 DV |
85 | #ifdef CONFIG_LOCKDEP |
86 | static struct lockdep_map console_lock_dep_map = { | |
87 | .name = "console_lock" | |
88 | }; | |
89 | #endif | |
90 | ||
750afe7b BP |
91 | enum devkmsg_log_bits { |
92 | __DEVKMSG_LOG_BIT_ON = 0, | |
93 | __DEVKMSG_LOG_BIT_OFF, | |
94 | __DEVKMSG_LOG_BIT_LOCK, | |
95 | }; | |
96 | ||
97 | enum devkmsg_log_masks { | |
98 | DEVKMSG_LOG_MASK_ON = BIT(__DEVKMSG_LOG_BIT_ON), | |
99 | DEVKMSG_LOG_MASK_OFF = BIT(__DEVKMSG_LOG_BIT_OFF), | |
100 | DEVKMSG_LOG_MASK_LOCK = BIT(__DEVKMSG_LOG_BIT_LOCK), | |
101 | }; | |
102 | ||
103 | /* Keep both the 'on' and 'off' bits clear, i.e. ratelimit by default: */ | |
104 | #define DEVKMSG_LOG_MASK_DEFAULT 0 | |
105 | ||
106 | static unsigned int __read_mostly devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; | |
107 | ||
108 | static int __control_devkmsg(char *str) | |
109 | { | |
110 | if (!str) | |
111 | return -EINVAL; | |
112 | ||
113 | if (!strncmp(str, "on", 2)) { | |
114 | devkmsg_log = DEVKMSG_LOG_MASK_ON; | |
115 | return 2; | |
116 | } else if (!strncmp(str, "off", 3)) { | |
117 | devkmsg_log = DEVKMSG_LOG_MASK_OFF; | |
118 | return 3; | |
119 | } else if (!strncmp(str, "ratelimit", 9)) { | |
120 | devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; | |
121 | return 9; | |
122 | } | |
123 | return -EINVAL; | |
124 | } | |
125 | ||
126 | static int __init control_devkmsg(char *str) | |
127 | { | |
128 | if (__control_devkmsg(str) < 0) | |
129 | return 1; | |
130 | ||
131 | /* | |
132 | * Set sysctl string accordingly: | |
133 | */ | |
134 | if (devkmsg_log == DEVKMSG_LOG_MASK_ON) { | |
135 | memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE); | |
136 | strncpy(devkmsg_log_str, "on", 2); | |
137 | } else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF) { | |
138 | memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE); | |
139 | strncpy(devkmsg_log_str, "off", 3); | |
140 | } | |
141 | /* else "ratelimit" which is set by default. */ | |
142 | ||
143 | /* | |
144 | * Sysctl cannot change it anymore. The kernel command line setting of | |
145 | * this parameter is to force the setting to be permanent throughout the | |
146 | * runtime of the system. This is a precation measure against userspace | |
147 | * trying to be a smarta** and attempting to change it up on us. | |
148 | */ | |
149 | devkmsg_log |= DEVKMSG_LOG_MASK_LOCK; | |
150 | ||
151 | return 0; | |
152 | } | |
153 | __setup("printk.devkmsg=", control_devkmsg); | |
154 | ||
155 | char devkmsg_log_str[DEVKMSG_STR_MAX_SIZE] = "ratelimit"; | |
156 | ||
157 | int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, | |
158 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
159 | { | |
160 | char old_str[DEVKMSG_STR_MAX_SIZE]; | |
161 | unsigned int old; | |
162 | int err; | |
163 | ||
164 | if (write) { | |
165 | if (devkmsg_log & DEVKMSG_LOG_MASK_LOCK) | |
166 | return -EINVAL; | |
167 | ||
168 | old = devkmsg_log; | |
169 | strncpy(old_str, devkmsg_log_str, DEVKMSG_STR_MAX_SIZE); | |
170 | } | |
171 | ||
172 | err = proc_dostring(table, write, buffer, lenp, ppos); | |
173 | if (err) | |
174 | return err; | |
175 | ||
176 | if (write) { | |
177 | err = __control_devkmsg(devkmsg_log_str); | |
178 | ||
179 | /* | |
180 | * Do not accept an unknown string OR a known string with | |
181 | * trailing crap... | |
182 | */ | |
183 | if (err < 0 || (err + 1 != *lenp)) { | |
184 | ||
185 | /* ... and restore old setting. */ | |
186 | devkmsg_log = old; | |
187 | strncpy(devkmsg_log_str, old_str, DEVKMSG_STR_MAX_SIZE); | |
188 | ||
189 | return -EINVAL; | |
190 | } | |
191 | } | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
6fe29354 TH |
196 | /* |
197 | * Number of registered extended console drivers. | |
198 | * | |
199 | * If extended consoles are present, in-kernel cont reassembly is disabled | |
200 | * and each fragment is stored as a separate log entry with proper | |
201 | * continuation flag so that every emitted message has full metadata. This | |
202 | * doesn't change the result for regular consoles or /proc/kmsg. For | |
203 | * /dev/kmsg, as long as the reader concatenates messages according to | |
204 | * consecutive continuation flags, the end result should be the same too. | |
205 | */ | |
206 | static int nr_ext_console_drivers; | |
207 | ||
bd8d7cf5 JK |
208 | /* |
209 | * Helper macros to handle lockdep when locking/unlocking console_sem. We use | |
210 | * macros instead of functions so that _RET_IP_ contains useful information. | |
211 | */ | |
212 | #define down_console_sem() do { \ | |
213 | down(&console_sem);\ | |
214 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\ | |
215 | } while (0) | |
216 | ||
217 | static int __down_trylock_console_sem(unsigned long ip) | |
218 | { | |
f975237b SS |
219 | int lock_failed; |
220 | unsigned long flags; | |
221 | ||
222 | /* | |
223 | * Here and in __up_console_sem() we need to be in safe mode, | |
224 | * because spindump/WARN/etc from under console ->lock will | |
225 | * deadlock in printk()->down_trylock_console_sem() otherwise. | |
226 | */ | |
227 | printk_safe_enter_irqsave(flags); | |
228 | lock_failed = down_trylock(&console_sem); | |
229 | printk_safe_exit_irqrestore(flags); | |
230 | ||
231 | if (lock_failed) | |
bd8d7cf5 JK |
232 | return 1; |
233 | mutex_acquire(&console_lock_dep_map, 0, 1, ip); | |
234 | return 0; | |
235 | } | |
236 | #define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_) | |
237 | ||
f975237b SS |
238 | static void __up_console_sem(unsigned long ip) |
239 | { | |
240 | unsigned long flags; | |
241 | ||
242 | mutex_release(&console_lock_dep_map, 1, ip); | |
243 | ||
244 | printk_safe_enter_irqsave(flags); | |
245 | up(&console_sem); | |
246 | printk_safe_exit_irqrestore(flags); | |
247 | } | |
248 | #define up_console_sem() __up_console_sem(_RET_IP_) | |
bd8d7cf5 | 249 | |
1da177e4 LT |
250 | /* |
251 | * This is used for debugging the mess that is the VT code by | |
252 | * keeping track if we have the console semaphore held. It's | |
253 | * definitely not the perfect debug tool (we don't know if _WE_ | |
0b90fec3 AE |
254 | * hold it and are racing, but it helps tracking those weird code |
255 | * paths in the console code where we end up in places I want | |
256 | * locked without the console sempahore held). | |
1da177e4 | 257 | */ |
557240b4 | 258 | static int console_locked, console_suspended; |
1da177e4 | 259 | |
fe3d8ad3 FT |
260 | /* |
261 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
262 | */ | |
263 | static struct console *exclusive_console; | |
264 | ||
1da177e4 LT |
265 | /* |
266 | * Array of consoles built from command line options (console=) | |
267 | */ | |
1da177e4 LT |
268 | |
269 | #define MAX_CMDLINECONSOLES 8 | |
270 | ||
271 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
cf39bf58 | 272 | static int console_cmdline_cnt; |
d197c43d | 273 | |
1da177e4 | 274 | static int preferred_console = -1; |
9e124fe1 MA |
275 | int console_set_on_cmdline; |
276 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
277 | |
278 | /* Flag: console code may call schedule() */ | |
279 | static int console_may_schedule; | |
280 | ||
7ff9554b KS |
281 | /* |
282 | * The printk log buffer consists of a chain of concatenated variable | |
283 | * length records. Every record starts with a record header, containing | |
284 | * the overall length of the record. | |
285 | * | |
286 | * The heads to the first and last entry in the buffer, as well as the | |
0b90fec3 AE |
287 | * sequence numbers of these entries are maintained when messages are |
288 | * stored. | |
7ff9554b KS |
289 | * |
290 | * If the heads indicate available messages, the length in the header | |
291 | * tells the start next message. A length == 0 for the next message | |
292 | * indicates a wrap-around to the beginning of the buffer. | |
293 | * | |
294 | * Every record carries the monotonic timestamp in microseconds, as well as | |
295 | * the standard userspace syslog level and syslog facility. The usual | |
296 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
297 | * a matching syslog facility, by default LOG_USER. The origin of every | |
298 | * message can be reliably determined that way. | |
299 | * | |
300 | * The human readable log message directly follows the message header. The | |
301 | * length of the message text is stored in the header, the stored message | |
302 | * is not terminated. | |
303 | * | |
e11fea92 KS |
304 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
305 | * to provide userspace with a machine-readable message context. | |
306 | * | |
307 | * Examples for well-defined, commonly used property names are: | |
308 | * DEVICE=b12:8 device identifier | |
309 | * b12:8 block dev_t | |
310 | * c127:3 char dev_t | |
311 | * n8 netdev ifindex | |
312 | * +sound:card0 subsystem:devname | |
313 | * SUBSYSTEM=pci driver-core subsystem name | |
314 | * | |
315 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
316 | * follows directly after a '=' character. Every property is terminated by | |
317 | * a '\0' character. The last property is not terminated. | |
318 | * | |
319 | * Example of a message structure: | |
320 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
321 | * 0008 34 00 record is 52 bytes long | |
322 | * 000a 0b 00 text is 11 bytes long | |
323 | * 000c 1f 00 dictionary is 23 bytes long | |
324 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
325 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
326 | * 69 6e 65 "ine" | |
327 | * 001b 44 45 56 49 43 "DEVIC" | |
328 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
329 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
330 | * 67 "g" | |
331 | * 0032 00 00 00 padding to next message header | |
332 | * | |
62e32ac3 | 333 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
334 | * userspace, it is a kernel-private implementation detail that might |
335 | * need to be changed in the future, when the requirements change. | |
336 | * | |
337 | * /dev/kmsg exports the structured data in the following line format: | |
b389645f AO |
338 | * "<level>,<sequnum>,<timestamp>,<contflag>[,additional_values, ... ];<message text>\n" |
339 | * | |
340 | * Users of the export format should ignore possible additional values | |
341 | * separated by ',', and find the message after the ';' character. | |
e11fea92 KS |
342 | * |
343 | * The optional key/value pairs are attached as continuation lines starting | |
344 | * with a space character and terminated by a newline. All possible | |
345 | * non-prinatable characters are escaped in the "\xff" notation. | |
7ff9554b KS |
346 | */ |
347 | ||
084681d1 | 348 | enum log_flags { |
5becfb1d KS |
349 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
350 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
351 | LOG_PREFIX = 4, /* text started with a prefix */ | |
352 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
353 | }; |
354 | ||
62e32ac3 | 355 | struct printk_log { |
7ff9554b KS |
356 | u64 ts_nsec; /* timestamp in nanoseconds */ |
357 | u16 len; /* length of entire record */ | |
358 | u16 text_len; /* length of text buffer */ | |
359 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
360 | u8 facility; /* syslog facility */ |
361 | u8 flags:5; /* internal record flags */ | |
362 | u8 level:3; /* syslog level */ | |
5c9cf8af AR |
363 | } |
364 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS | |
365 | __packed __aligned(4) | |
366 | #endif | |
367 | ; | |
7ff9554b KS |
368 | |
369 | /* | |
458df9fd SR |
370 | * The logbuf_lock protects kmsg buffer, indices, counters. This can be taken |
371 | * within the scheduler's rq lock. It must be released before calling | |
372 | * console_unlock() or anything else that might wake up a process. | |
7ff9554b | 373 | */ |
cf9b1106 | 374 | DEFINE_RAW_SPINLOCK(logbuf_lock); |
d59745ce | 375 | |
de6fcbdb SS |
376 | /* |
377 | * Helper macros to lock/unlock logbuf_lock and switch between | |
378 | * printk-safe/unsafe modes. | |
379 | */ | |
380 | #define logbuf_lock_irq() \ | |
381 | do { \ | |
382 | printk_safe_enter_irq(); \ | |
383 | raw_spin_lock(&logbuf_lock); \ | |
384 | } while (0) | |
385 | ||
386 | #define logbuf_unlock_irq() \ | |
387 | do { \ | |
388 | raw_spin_unlock(&logbuf_lock); \ | |
389 | printk_safe_exit_irq(); \ | |
390 | } while (0) | |
391 | ||
392 | #define logbuf_lock_irqsave(flags) \ | |
393 | do { \ | |
394 | printk_safe_enter_irqsave(flags); \ | |
395 | raw_spin_lock(&logbuf_lock); \ | |
396 | } while (0) | |
397 | ||
398 | #define logbuf_unlock_irqrestore(flags) \ | |
399 | do { \ | |
400 | raw_spin_unlock(&logbuf_lock); \ | |
401 | printk_safe_exit_irqrestore(flags); \ | |
402 | } while (0) | |
403 | ||
96efedf1 | 404 | #ifdef CONFIG_PRINTK |
dc72c32e | 405 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
406 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
407 | static u64 syslog_seq; | |
408 | static u32 syslog_idx; | |
eb02dac9 | 409 | static size_t syslog_partial; |
7ff9554b KS |
410 | |
411 | /* index and sequence number of the first record stored in the buffer */ | |
412 | static u64 log_first_seq; | |
413 | static u32 log_first_idx; | |
414 | ||
415 | /* index and sequence number of the next record to store in the buffer */ | |
416 | static u64 log_next_seq; | |
417 | static u32 log_next_idx; | |
418 | ||
eab07260 KS |
419 | /* the next printk record to write to the console */ |
420 | static u64 console_seq; | |
421 | static u32 console_idx; | |
eab07260 | 422 | |
7ff9554b KS |
423 | /* the next printk record to read after the last 'clear' command */ |
424 | static u64 clear_seq; | |
425 | static u32 clear_idx; | |
426 | ||
70498253 | 427 | #define PREFIX_MAX 32 |
249771b8 | 428 | #define LOG_LINE_MAX (1024 - PREFIX_MAX) |
7f3a781d | 429 | |
3824657c MK |
430 | #define LOG_LEVEL(v) ((v) & 0x07) |
431 | #define LOG_FACILITY(v) ((v) >> 3 & 0xff) | |
432 | ||
7f3a781d | 433 | /* record buffer */ |
62e32ac3 | 434 | #define LOG_ALIGN __alignof__(struct printk_log) |
7f3a781d | 435 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 436 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
437 | static char *log_buf = __log_buf; |
438 | static u32 log_buf_len = __LOG_BUF_LEN; | |
439 | ||
14c4000a VH |
440 | /* Return log buffer address */ |
441 | char *log_buf_addr_get(void) | |
442 | { | |
443 | return log_buf; | |
444 | } | |
445 | ||
446 | /* Return log buffer size */ | |
447 | u32 log_buf_len_get(void) | |
448 | { | |
449 | return log_buf_len; | |
450 | } | |
451 | ||
7ff9554b | 452 | /* human readable text of the record */ |
62e32ac3 | 453 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 454 | { |
62e32ac3 | 455 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
456 | } |
457 | ||
458 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 459 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 460 | { |
62e32ac3 | 461 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
462 | } |
463 | ||
464 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 465 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 466 | { |
62e32ac3 | 467 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
468 | |
469 | /* | |
470 | * A length == 0 record is the end of buffer marker. Wrap around and | |
471 | * read the message at the start of the buffer. | |
472 | */ | |
473 | if (!msg->len) | |
62e32ac3 | 474 | return (struct printk_log *)log_buf; |
7ff9554b KS |
475 | return msg; |
476 | } | |
477 | ||
478 | /* get next record; idx must point to valid msg */ | |
479 | static u32 log_next(u32 idx) | |
480 | { | |
62e32ac3 | 481 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
482 | |
483 | /* length == 0 indicates the end of the buffer; wrap */ | |
484 | /* | |
485 | * A length == 0 record is the end of buffer marker. Wrap around and | |
486 | * read the message at the start of the buffer as *this* one, and | |
487 | * return the one after that. | |
488 | */ | |
489 | if (!msg->len) { | |
62e32ac3 | 490 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
491 | return msg->len; |
492 | } | |
493 | return idx + msg->len; | |
494 | } | |
495 | ||
f40e4b9f PM |
496 | /* |
497 | * Check whether there is enough free space for the given message. | |
498 | * | |
499 | * The same values of first_idx and next_idx mean that the buffer | |
500 | * is either empty or full. | |
501 | * | |
502 | * If the buffer is empty, we must respect the position of the indexes. | |
503 | * They cannot be reset to the beginning of the buffer. | |
504 | */ | |
505 | static int logbuf_has_space(u32 msg_size, bool empty) | |
0a581694 PM |
506 | { |
507 | u32 free; | |
508 | ||
f40e4b9f | 509 | if (log_next_idx > log_first_idx || empty) |
0a581694 PM |
510 | free = max(log_buf_len - log_next_idx, log_first_idx); |
511 | else | |
512 | free = log_first_idx - log_next_idx; | |
513 | ||
514 | /* | |
515 | * We need space also for an empty header that signalizes wrapping | |
516 | * of the buffer. | |
517 | */ | |
518 | return free >= msg_size + sizeof(struct printk_log); | |
519 | } | |
520 | ||
f40e4b9f | 521 | static int log_make_free_space(u32 msg_size) |
0a581694 | 522 | { |
f468908b ID |
523 | while (log_first_seq < log_next_seq && |
524 | !logbuf_has_space(msg_size, false)) { | |
0b90fec3 | 525 | /* drop old messages until we have enough contiguous space */ |
0a581694 PM |
526 | log_first_idx = log_next(log_first_idx); |
527 | log_first_seq++; | |
528 | } | |
f40e4b9f | 529 | |
f468908b ID |
530 | if (clear_seq < log_first_seq) { |
531 | clear_seq = log_first_seq; | |
532 | clear_idx = log_first_idx; | |
533 | } | |
534 | ||
f40e4b9f | 535 | /* sequence numbers are equal, so the log buffer is empty */ |
f468908b | 536 | if (logbuf_has_space(msg_size, log_first_seq == log_next_seq)) |
f40e4b9f PM |
537 | return 0; |
538 | ||
539 | return -ENOMEM; | |
0a581694 PM |
540 | } |
541 | ||
85c87043 PM |
542 | /* compute the message size including the padding bytes */ |
543 | static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) | |
544 | { | |
545 | u32 size; | |
546 | ||
547 | size = sizeof(struct printk_log) + text_len + dict_len; | |
548 | *pad_len = (-size) & (LOG_ALIGN - 1); | |
549 | size += *pad_len; | |
550 | ||
551 | return size; | |
552 | } | |
553 | ||
55bd53a4 PM |
554 | /* |
555 | * Define how much of the log buffer we could take at maximum. The value | |
556 | * must be greater than two. Note that only half of the buffer is available | |
557 | * when the index points to the middle. | |
558 | */ | |
559 | #define MAX_LOG_TAKE_PART 4 | |
560 | static const char trunc_msg[] = "<truncated>"; | |
561 | ||
562 | static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len, | |
563 | u16 *dict_len, u32 *pad_len) | |
564 | { | |
565 | /* | |
566 | * The message should not take the whole buffer. Otherwise, it might | |
567 | * get removed too soon. | |
568 | */ | |
569 | u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART; | |
570 | if (*text_len > max_text_len) | |
571 | *text_len = max_text_len; | |
572 | /* enable the warning message */ | |
573 | *trunc_msg_len = strlen(trunc_msg); | |
574 | /* disable the "dict" completely */ | |
575 | *dict_len = 0; | |
576 | /* compute the size again, count also the warning message */ | |
577 | return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len); | |
578 | } | |
579 | ||
7ff9554b | 580 | /* insert record into the buffer, discard old ones, update heads */ |
034633cc PM |
581 | static int log_store(int facility, int level, |
582 | enum log_flags flags, u64 ts_nsec, | |
583 | const char *dict, u16 dict_len, | |
584 | const char *text, u16 text_len) | |
7ff9554b | 585 | { |
62e32ac3 | 586 | struct printk_log *msg; |
7ff9554b | 587 | u32 size, pad_len; |
55bd53a4 | 588 | u16 trunc_msg_len = 0; |
7ff9554b KS |
589 | |
590 | /* number of '\0' padding bytes to next message */ | |
85c87043 | 591 | size = msg_used_size(text_len, dict_len, &pad_len); |
7ff9554b | 592 | |
55bd53a4 PM |
593 | if (log_make_free_space(size)) { |
594 | /* truncate the message if it is too long for empty buffer */ | |
595 | size = truncate_msg(&text_len, &trunc_msg_len, | |
596 | &dict_len, &pad_len); | |
597 | /* survive when the log buffer is too small for trunc_msg */ | |
598 | if (log_make_free_space(size)) | |
034633cc | 599 | return 0; |
55bd53a4 | 600 | } |
7ff9554b | 601 | |
39b25109 | 602 | if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) { |
7ff9554b KS |
603 | /* |
604 | * This message + an additional empty header does not fit | |
605 | * at the end of the buffer. Add an empty header with len == 0 | |
606 | * to signify a wrap around. | |
607 | */ | |
62e32ac3 | 608 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
609 | log_next_idx = 0; |
610 | } | |
611 | ||
612 | /* fill message */ | |
62e32ac3 | 613 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
614 | memcpy(log_text(msg), text, text_len); |
615 | msg->text_len = text_len; | |
55bd53a4 PM |
616 | if (trunc_msg_len) { |
617 | memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len); | |
618 | msg->text_len += trunc_msg_len; | |
619 | } | |
7ff9554b KS |
620 | memcpy(log_dict(msg), dict, dict_len); |
621 | msg->dict_len = dict_len; | |
084681d1 KS |
622 | msg->facility = facility; |
623 | msg->level = level & 7; | |
624 | msg->flags = flags & 0x1f; | |
625 | if (ts_nsec > 0) | |
626 | msg->ts_nsec = ts_nsec; | |
627 | else | |
628 | msg->ts_nsec = local_clock(); | |
7ff9554b | 629 | memset(log_dict(msg) + dict_len, 0, pad_len); |
fce6e033 | 630 | msg->len = size; |
7ff9554b KS |
631 | |
632 | /* insert message */ | |
633 | log_next_idx += msg->len; | |
634 | log_next_seq++; | |
034633cc PM |
635 | |
636 | return msg->text_len; | |
7ff9554b | 637 | } |
d59745ce | 638 | |
e99aa461 | 639 | int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); |
637241a9 KC |
640 | |
641 | static int syslog_action_restricted(int type) | |
642 | { | |
643 | if (dmesg_restrict) | |
644 | return 1; | |
645 | /* | |
646 | * Unless restricted, we allow "read all" and "get buffer size" | |
647 | * for everybody. | |
648 | */ | |
649 | return type != SYSLOG_ACTION_READ_ALL && | |
650 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
651 | } | |
652 | ||
3ea4331c | 653 | int check_syslog_permissions(int type, int source) |
637241a9 KC |
654 | { |
655 | /* | |
656 | * If this is from /proc/kmsg and we've already opened it, then we've | |
657 | * already done the capabilities checks at open time. | |
658 | */ | |
3ea4331c | 659 | if (source == SYSLOG_FROM_PROC && type != SYSLOG_ACTION_OPEN) |
d194e5d6 | 660 | goto ok; |
637241a9 KC |
661 | |
662 | if (syslog_action_restricted(type)) { | |
663 | if (capable(CAP_SYSLOG)) | |
d194e5d6 | 664 | goto ok; |
637241a9 KC |
665 | /* |
666 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
667 | * a warning. | |
668 | */ | |
669 | if (capable(CAP_SYS_ADMIN)) { | |
670 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
671 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
672 | "(deprecated).\n", | |
673 | current->comm, task_pid_nr(current)); | |
d194e5d6 | 674 | goto ok; |
637241a9 KC |
675 | } |
676 | return -EPERM; | |
677 | } | |
d194e5d6 | 678 | ok: |
637241a9 KC |
679 | return security_syslog(type); |
680 | } | |
ee1d2674 | 681 | EXPORT_SYMBOL_GPL(check_syslog_permissions); |
637241a9 | 682 | |
d43ff430 TH |
683 | static void append_char(char **pp, char *e, char c) |
684 | { | |
685 | if (*pp < e) | |
686 | *(*pp)++ = c; | |
687 | } | |
637241a9 | 688 | |
0a295e67 | 689 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
5aa068ea | 690 | struct printk_log *msg, u64 seq) |
0a295e67 TH |
691 | { |
692 | u64 ts_usec = msg->ts_nsec; | |
0a295e67 TH |
693 | |
694 | do_div(ts_usec, 1000); | |
695 | ||
0a295e67 | 696 | return scnprintf(buf, size, "%u,%llu,%llu,%c;", |
5aa068ea LT |
697 | (msg->facility << 3) | msg->level, seq, ts_usec, |
698 | msg->flags & LOG_CONT ? 'c' : '-'); | |
0a295e67 TH |
699 | } |
700 | ||
701 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
702 | char *dict, size_t dict_len, | |
703 | char *text, size_t text_len) | |
704 | { | |
705 | char *p = buf, *e = buf + size; | |
706 | size_t i; | |
707 | ||
708 | /* escape non-printable characters */ | |
709 | for (i = 0; i < text_len; i++) { | |
710 | unsigned char c = text[i]; | |
711 | ||
712 | if (c < ' ' || c >= 127 || c == '\\') | |
713 | p += scnprintf(p, e - p, "\\x%02x", c); | |
714 | else | |
715 | append_char(&p, e, c); | |
716 | } | |
717 | append_char(&p, e, '\n'); | |
718 | ||
719 | if (dict_len) { | |
720 | bool line = true; | |
721 | ||
722 | for (i = 0; i < dict_len; i++) { | |
723 | unsigned char c = dict[i]; | |
724 | ||
725 | if (line) { | |
726 | append_char(&p, e, ' '); | |
727 | line = false; | |
728 | } | |
729 | ||
730 | if (c == '\0') { | |
731 | append_char(&p, e, '\n'); | |
732 | line = true; | |
733 | continue; | |
734 | } | |
735 | ||
736 | if (c < ' ' || c >= 127 || c == '\\') { | |
737 | p += scnprintf(p, e - p, "\\x%02x", c); | |
738 | continue; | |
739 | } | |
740 | ||
741 | append_char(&p, e, c); | |
742 | } | |
743 | append_char(&p, e, '\n'); | |
744 | } | |
745 | ||
746 | return p - buf; | |
747 | } | |
748 | ||
e11fea92 KS |
749 | /* /dev/kmsg - userspace message inject/listen interface */ |
750 | struct devkmsg_user { | |
751 | u64 seq; | |
752 | u32 idx; | |
750afe7b | 753 | struct ratelimit_state rs; |
e11fea92 | 754 | struct mutex lock; |
d43ff430 | 755 | char buf[CONSOLE_EXT_LOG_MAX]; |
e11fea92 KS |
756 | }; |
757 | ||
849f3127 | 758 | static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) |
e11fea92 KS |
759 | { |
760 | char *buf, *line; | |
e11fea92 KS |
761 | int level = default_message_loglevel; |
762 | int facility = 1; /* LOG_USER */ | |
750afe7b BP |
763 | struct file *file = iocb->ki_filp; |
764 | struct devkmsg_user *user = file->private_data; | |
66ee59af | 765 | size_t len = iov_iter_count(from); |
e11fea92 KS |
766 | ssize_t ret = len; |
767 | ||
750afe7b | 768 | if (!user || len > LOG_LINE_MAX) |
e11fea92 | 769 | return -EINVAL; |
750afe7b BP |
770 | |
771 | /* Ignore when user logging is disabled. */ | |
772 | if (devkmsg_log & DEVKMSG_LOG_MASK_OFF) | |
773 | return len; | |
774 | ||
775 | /* Ratelimit when not explicitly enabled. */ | |
776 | if (!(devkmsg_log & DEVKMSG_LOG_MASK_ON)) { | |
777 | if (!___ratelimit(&user->rs, current->comm)) | |
778 | return ret; | |
779 | } | |
780 | ||
e11fea92 KS |
781 | buf = kmalloc(len+1, GFP_KERNEL); |
782 | if (buf == NULL) | |
783 | return -ENOMEM; | |
784 | ||
849f3127 | 785 | buf[len] = '\0'; |
cbbd26b8 | 786 | if (!copy_from_iter_full(buf, len, from)) { |
849f3127 AV |
787 | kfree(buf); |
788 | return -EFAULT; | |
e11fea92 KS |
789 | } |
790 | ||
791 | /* | |
792 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
793 | * the decimal value represents 32bit, the lower 3 bit are the log | |
794 | * level, the rest are the log facility. | |
795 | * | |
796 | * If no prefix or no userspace facility is specified, we | |
797 | * enforce LOG_USER, to be able to reliably distinguish | |
798 | * kernel-generated messages from userspace-injected ones. | |
799 | */ | |
800 | line = buf; | |
801 | if (line[0] == '<') { | |
802 | char *endp = NULL; | |
3824657c | 803 | unsigned int u; |
e11fea92 | 804 | |
3824657c | 805 | u = simple_strtoul(line + 1, &endp, 10); |
e11fea92 | 806 | if (endp && endp[0] == '>') { |
3824657c MK |
807 | level = LOG_LEVEL(u); |
808 | if (LOG_FACILITY(u) != 0) | |
809 | facility = LOG_FACILITY(u); | |
e11fea92 KS |
810 | endp++; |
811 | len -= endp - line; | |
812 | line = endp; | |
813 | } | |
814 | } | |
e11fea92 KS |
815 | |
816 | printk_emit(facility, level, NULL, 0, "%s", line); | |
e11fea92 KS |
817 | kfree(buf); |
818 | return ret; | |
819 | } | |
820 | ||
821 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
822 | size_t count, loff_t *ppos) | |
823 | { | |
824 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 825 | struct printk_log *msg; |
e11fea92 KS |
826 | size_t len; |
827 | ssize_t ret; | |
828 | ||
829 | if (!user) | |
830 | return -EBADF; | |
831 | ||
4a77a5a0 YL |
832 | ret = mutex_lock_interruptible(&user->lock); |
833 | if (ret) | |
834 | return ret; | |
de6fcbdb SS |
835 | |
836 | logbuf_lock_irq(); | |
e11fea92 KS |
837 | while (user->seq == log_next_seq) { |
838 | if (file->f_flags & O_NONBLOCK) { | |
839 | ret = -EAGAIN; | |
de6fcbdb | 840 | logbuf_unlock_irq(); |
e11fea92 KS |
841 | goto out; |
842 | } | |
843 | ||
de6fcbdb | 844 | logbuf_unlock_irq(); |
e11fea92 KS |
845 | ret = wait_event_interruptible(log_wait, |
846 | user->seq != log_next_seq); | |
847 | if (ret) | |
848 | goto out; | |
de6fcbdb | 849 | logbuf_lock_irq(); |
e11fea92 KS |
850 | } |
851 | ||
852 | if (user->seq < log_first_seq) { | |
853 | /* our last seen message is gone, return error and reset */ | |
854 | user->idx = log_first_idx; | |
855 | user->seq = log_first_seq; | |
856 | ret = -EPIPE; | |
de6fcbdb | 857 | logbuf_unlock_irq(); |
e11fea92 KS |
858 | goto out; |
859 | } | |
860 | ||
861 | msg = log_from_idx(user->idx); | |
0a295e67 | 862 | len = msg_print_ext_header(user->buf, sizeof(user->buf), |
5aa068ea | 863 | msg, user->seq); |
0a295e67 TH |
864 | len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len, |
865 | log_dict(msg), msg->dict_len, | |
866 | log_text(msg), msg->text_len); | |
d39f3d77 | 867 | |
e11fea92 KS |
868 | user->idx = log_next(user->idx); |
869 | user->seq++; | |
de6fcbdb | 870 | logbuf_unlock_irq(); |
e11fea92 KS |
871 | |
872 | if (len > count) { | |
873 | ret = -EINVAL; | |
874 | goto out; | |
875 | } | |
876 | ||
877 | if (copy_to_user(buf, user->buf, len)) { | |
878 | ret = -EFAULT; | |
879 | goto out; | |
880 | } | |
881 | ret = len; | |
882 | out: | |
883 | mutex_unlock(&user->lock); | |
884 | return ret; | |
885 | } | |
886 | ||
887 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
888 | { | |
889 | struct devkmsg_user *user = file->private_data; | |
890 | loff_t ret = 0; | |
891 | ||
892 | if (!user) | |
893 | return -EBADF; | |
894 | if (offset) | |
895 | return -ESPIPE; | |
896 | ||
de6fcbdb | 897 | logbuf_lock_irq(); |
e11fea92 KS |
898 | switch (whence) { |
899 | case SEEK_SET: | |
900 | /* the first record */ | |
901 | user->idx = log_first_idx; | |
902 | user->seq = log_first_seq; | |
903 | break; | |
904 | case SEEK_DATA: | |
905 | /* | |
906 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
907 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
908 | * changes no global state, and does not clear anything. | |
909 | */ | |
910 | user->idx = clear_idx; | |
911 | user->seq = clear_seq; | |
912 | break; | |
913 | case SEEK_END: | |
914 | /* after the last record */ | |
915 | user->idx = log_next_idx; | |
916 | user->seq = log_next_seq; | |
917 | break; | |
918 | default: | |
919 | ret = -EINVAL; | |
920 | } | |
de6fcbdb | 921 | logbuf_unlock_irq(); |
e11fea92 KS |
922 | return ret; |
923 | } | |
924 | ||
925 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
926 | { | |
927 | struct devkmsg_user *user = file->private_data; | |
928 | int ret = 0; | |
929 | ||
930 | if (!user) | |
931 | return POLLERR|POLLNVAL; | |
932 | ||
933 | poll_wait(file, &log_wait, wait); | |
934 | ||
de6fcbdb | 935 | logbuf_lock_irq(); |
e11fea92 KS |
936 | if (user->seq < log_next_seq) { |
937 | /* return error when data has vanished underneath us */ | |
938 | if (user->seq < log_first_seq) | |
939 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
940 | else |
941 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 942 | } |
de6fcbdb | 943 | logbuf_unlock_irq(); |
e11fea92 KS |
944 | |
945 | return ret; | |
946 | } | |
947 | ||
948 | static int devkmsg_open(struct inode *inode, struct file *file) | |
949 | { | |
950 | struct devkmsg_user *user; | |
951 | int err; | |
952 | ||
750afe7b BP |
953 | if (devkmsg_log & DEVKMSG_LOG_MASK_OFF) |
954 | return -EPERM; | |
e11fea92 | 955 | |
750afe7b BP |
956 | /* write-only does not need any file context */ |
957 | if ((file->f_flags & O_ACCMODE) != O_WRONLY) { | |
958 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, | |
959 | SYSLOG_FROM_READER); | |
960 | if (err) | |
961 | return err; | |
962 | } | |
e11fea92 KS |
963 | |
964 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
965 | if (!user) | |
966 | return -ENOMEM; | |
967 | ||
750afe7b BP |
968 | ratelimit_default_init(&user->rs); |
969 | ratelimit_set_flags(&user->rs, RATELIMIT_MSG_ON_RELEASE); | |
970 | ||
e11fea92 KS |
971 | mutex_init(&user->lock); |
972 | ||
de6fcbdb | 973 | logbuf_lock_irq(); |
e11fea92 KS |
974 | user->idx = log_first_idx; |
975 | user->seq = log_first_seq; | |
de6fcbdb | 976 | logbuf_unlock_irq(); |
e11fea92 KS |
977 | |
978 | file->private_data = user; | |
979 | return 0; | |
980 | } | |
981 | ||
982 | static int devkmsg_release(struct inode *inode, struct file *file) | |
983 | { | |
984 | struct devkmsg_user *user = file->private_data; | |
985 | ||
986 | if (!user) | |
987 | return 0; | |
988 | ||
750afe7b BP |
989 | ratelimit_state_exit(&user->rs); |
990 | ||
e11fea92 KS |
991 | mutex_destroy(&user->lock); |
992 | kfree(user); | |
993 | return 0; | |
994 | } | |
995 | ||
996 | const struct file_operations kmsg_fops = { | |
997 | .open = devkmsg_open, | |
998 | .read = devkmsg_read, | |
849f3127 | 999 | .write_iter = devkmsg_write, |
e11fea92 KS |
1000 | .llseek = devkmsg_llseek, |
1001 | .poll = devkmsg_poll, | |
1002 | .release = devkmsg_release, | |
1003 | }; | |
1004 | ||
692f66f2 | 1005 | #ifdef CONFIG_CRASH_CORE |
04d491ab | 1006 | /* |
4c1ace64 | 1007 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 1008 | * |
4c1ace64 | 1009 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
1010 | * obtain access to symbols that are otherwise very difficult to locate. These |
1011 | * symbols are specifically used so that utilities can access and extract the | |
1012 | * dmesg log from a vmcore file after a crash. | |
1013 | */ | |
692f66f2 | 1014 | void log_buf_vmcoreinfo_setup(void) |
04d491ab NH |
1015 | { |
1016 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 1017 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b | 1018 | VMCOREINFO_SYMBOL(log_first_idx); |
f468908b | 1019 | VMCOREINFO_SYMBOL(clear_idx); |
7ff9554b | 1020 | VMCOREINFO_SYMBOL(log_next_idx); |
6791457a | 1021 | /* |
62e32ac3 | 1022 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
1023 | * parse it and detect any changes to structure down the line. |
1024 | */ | |
62e32ac3 JP |
1025 | VMCOREINFO_STRUCT_SIZE(printk_log); |
1026 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
1027 | VMCOREINFO_OFFSET(printk_log, len); | |
1028 | VMCOREINFO_OFFSET(printk_log, text_len); | |
1029 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
1030 | } |
1031 | #endif | |
1032 | ||
162a7e75 MT |
1033 | /* requested log_buf_len from kernel cmdline */ |
1034 | static unsigned long __initdata new_log_buf_len; | |
1035 | ||
c0a318a3 LR |
1036 | /* we practice scaling the ring buffer by powers of 2 */ |
1037 | static void __init log_buf_len_update(unsigned size) | |
1da177e4 | 1038 | { |
1da177e4 LT |
1039 | if (size) |
1040 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
1041 | if (size > log_buf_len) |
1042 | new_log_buf_len = size; | |
c0a318a3 LR |
1043 | } |
1044 | ||
1045 | /* save requested log_buf_len since it's too early to process it */ | |
1046 | static int __init log_buf_len_setup(char *str) | |
1047 | { | |
1048 | unsigned size = memparse(str, &str); | |
1049 | ||
1050 | log_buf_len_update(size); | |
162a7e75 MT |
1051 | |
1052 | return 0; | |
1da177e4 | 1053 | } |
162a7e75 MT |
1054 | early_param("log_buf_len", log_buf_len_setup); |
1055 | ||
2240a31d GU |
1056 | #ifdef CONFIG_SMP |
1057 | #define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT) | |
1058 | ||
23b2899f LR |
1059 | static void __init log_buf_add_cpu(void) |
1060 | { | |
1061 | unsigned int cpu_extra; | |
1062 | ||
1063 | /* | |
1064 | * archs should set up cpu_possible_bits properly with | |
1065 | * set_cpu_possible() after setup_arch() but just in | |
1066 | * case lets ensure this is valid. | |
1067 | */ | |
1068 | if (num_possible_cpus() == 1) | |
1069 | return; | |
1070 | ||
1071 | cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; | |
1072 | ||
1073 | /* by default this will only continue through for large > 64 CPUs */ | |
1074 | if (cpu_extra <= __LOG_BUF_LEN / 2) | |
1075 | return; | |
1076 | ||
1077 | pr_info("log_buf_len individual max cpu contribution: %d bytes\n", | |
1078 | __LOG_CPU_MAX_BUF_LEN); | |
1079 | pr_info("log_buf_len total cpu_extra contributions: %d bytes\n", | |
1080 | cpu_extra); | |
1081 | pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN); | |
1082 | ||
1083 | log_buf_len_update(cpu_extra + __LOG_BUF_LEN); | |
1084 | } | |
2240a31d GU |
1085 | #else /* !CONFIG_SMP */ |
1086 | static inline void log_buf_add_cpu(void) {} | |
1087 | #endif /* CONFIG_SMP */ | |
23b2899f | 1088 | |
162a7e75 MT |
1089 | void __init setup_log_buf(int early) |
1090 | { | |
1091 | unsigned long flags; | |
162a7e75 MT |
1092 | char *new_log_buf; |
1093 | int free; | |
1094 | ||
23b2899f LR |
1095 | if (log_buf != __log_buf) |
1096 | return; | |
1097 | ||
1098 | if (!early && !new_log_buf_len) | |
1099 | log_buf_add_cpu(); | |
1100 | ||
162a7e75 MT |
1101 | if (!new_log_buf_len) |
1102 | return; | |
1da177e4 | 1103 | |
162a7e75 | 1104 | if (early) { |
9da791df | 1105 | new_log_buf = |
70300177 | 1106 | memblock_virt_alloc(new_log_buf_len, LOG_ALIGN); |
162a7e75 | 1107 | } else { |
70300177 LR |
1108 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, |
1109 | LOG_ALIGN); | |
162a7e75 MT |
1110 | } |
1111 | ||
1112 | if (unlikely(!new_log_buf)) { | |
1113 | pr_err("log_buf_len: %ld bytes not available\n", | |
1114 | new_log_buf_len); | |
1115 | return; | |
1116 | } | |
1117 | ||
de6fcbdb | 1118 | logbuf_lock_irqsave(flags); |
162a7e75 MT |
1119 | log_buf_len = new_log_buf_len; |
1120 | log_buf = new_log_buf; | |
1121 | new_log_buf_len = 0; | |
7ff9554b KS |
1122 | free = __LOG_BUF_LEN - log_next_idx; |
1123 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
de6fcbdb | 1124 | logbuf_unlock_irqrestore(flags); |
162a7e75 | 1125 | |
f5405172 | 1126 | pr_info("log_buf_len: %d bytes\n", log_buf_len); |
162a7e75 MT |
1127 | pr_info("early log buf free: %d(%d%%)\n", |
1128 | free, (free * 100) / __LOG_BUF_LEN); | |
1129 | } | |
1da177e4 | 1130 | |
2fa72c8f AC |
1131 | static bool __read_mostly ignore_loglevel; |
1132 | ||
1133 | static int __init ignore_loglevel_setup(char *str) | |
1134 | { | |
d25d9fec | 1135 | ignore_loglevel = true; |
27083bac | 1136 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
1137 | |
1138 | return 0; | |
1139 | } | |
1140 | ||
1141 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
1142 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
205bd3d2 JP |
1143 | MODULE_PARM_DESC(ignore_loglevel, |
1144 | "ignore loglevel setting (prints all kernel messages to the console)"); | |
2fa72c8f | 1145 | |
cf775444 SS |
1146 | static bool suppress_message_printing(int level) |
1147 | { | |
1148 | return (level >= console_loglevel && !ignore_loglevel); | |
1149 | } | |
1150 | ||
bfe8df3d RD |
1151 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
1152 | ||
674dff65 | 1153 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 1154 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
1155 | |
1156 | static int __init boot_delay_setup(char *str) | |
1157 | { | |
1158 | unsigned long lpj; | |
bfe8df3d RD |
1159 | |
1160 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
1161 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
1162 | ||
1163 | get_option(&str, &boot_delay); | |
1164 | if (boot_delay > 10 * 1000) | |
1165 | boot_delay = 0; | |
1166 | ||
3a3b6ed2 DY |
1167 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
1168 | "HZ: %d, loops_per_msec: %llu\n", | |
1169 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 1170 | return 0; |
bfe8df3d | 1171 | } |
29e9d225 | 1172 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 1173 | |
2fa72c8f | 1174 | static void boot_delay_msec(int level) |
bfe8df3d RD |
1175 | { |
1176 | unsigned long long k; | |
1177 | unsigned long timeout; | |
1178 | ||
2fa72c8f | 1179 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
cf775444 | 1180 | || suppress_message_printing(level)) { |
bfe8df3d | 1181 | return; |
2fa72c8f | 1182 | } |
bfe8df3d | 1183 | |
3a3b6ed2 | 1184 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
1185 | |
1186 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
1187 | while (k) { | |
1188 | k--; | |
1189 | cpu_relax(); | |
1190 | /* | |
1191 | * use (volatile) jiffies to prevent | |
1192 | * compiler reduction; loop termination via jiffies | |
1193 | * is secondary and may or may not happen. | |
1194 | */ | |
1195 | if (time_after(jiffies, timeout)) | |
1196 | break; | |
1197 | touch_nmi_watchdog(); | |
1198 | } | |
1199 | } | |
1200 | #else | |
2fa72c8f | 1201 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
1202 | { |
1203 | } | |
1204 | #endif | |
1205 | ||
e99aa461 | 1206 | static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); |
7ff9554b KS |
1207 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
1208 | ||
084681d1 KS |
1209 | static size_t print_time(u64 ts, char *buf) |
1210 | { | |
1211 | unsigned long rem_nsec; | |
1212 | ||
1213 | if (!printk_time) | |
1214 | return 0; | |
1215 | ||
35dac27c RD |
1216 | rem_nsec = do_div(ts, 1000000000); |
1217 | ||
084681d1 | 1218 | if (!buf) |
35dac27c | 1219 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 1220 | |
084681d1 KS |
1221 | return sprintf(buf, "[%5lu.%06lu] ", |
1222 | (unsigned long)ts, rem_nsec / 1000); | |
1223 | } | |
1224 | ||
62e32ac3 | 1225 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 1226 | { |
3ce9a7c0 | 1227 | size_t len = 0; |
43a73a50 | 1228 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 1229 | |
3ce9a7c0 KS |
1230 | if (syslog) { |
1231 | if (buf) { | |
43a73a50 | 1232 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
1233 | } else { |
1234 | len += 3; | |
43a73a50 KS |
1235 | if (prefix > 999) |
1236 | len += 3; | |
1237 | else if (prefix > 99) | |
1238 | len += 2; | |
1239 | else if (prefix > 9) | |
3ce9a7c0 KS |
1240 | len++; |
1241 | } | |
1242 | } | |
649e6ee3 | 1243 | |
084681d1 | 1244 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 1245 | return len; |
649e6ee3 KS |
1246 | } |
1247 | ||
5aa068ea | 1248 | static size_t msg_print_text(const struct printk_log *msg, bool syslog, char *buf, size_t size) |
7ff9554b | 1249 | { |
3ce9a7c0 KS |
1250 | const char *text = log_text(msg); |
1251 | size_t text_size = msg->text_len; | |
1252 | size_t len = 0; | |
1253 | ||
1254 | do { | |
1255 | const char *next = memchr(text, '\n', text_size); | |
1256 | size_t text_len; | |
1257 | ||
1258 | if (next) { | |
1259 | text_len = next - text; | |
1260 | next++; | |
1261 | text_size -= next - text; | |
1262 | } else { | |
1263 | text_len = text_size; | |
1264 | } | |
7ff9554b | 1265 | |
3ce9a7c0 KS |
1266 | if (buf) { |
1267 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1268 | text_len + 1 >= size - len) |
3ce9a7c0 | 1269 | break; |
7ff9554b | 1270 | |
5aa068ea | 1271 | len += print_prefix(msg, syslog, buf + len); |
3ce9a7c0 KS |
1272 | memcpy(buf + len, text, text_len); |
1273 | len += text_len; | |
5aa068ea | 1274 | buf[len++] = '\n'; |
3ce9a7c0 KS |
1275 | } else { |
1276 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5aa068ea | 1277 | len += print_prefix(msg, syslog, NULL); |
5becfb1d | 1278 | len += text_len; |
5aa068ea | 1279 | len++; |
3ce9a7c0 | 1280 | } |
7ff9554b | 1281 | |
3ce9a7c0 KS |
1282 | text = next; |
1283 | } while (text); | |
7ff9554b | 1284 | |
7ff9554b KS |
1285 | return len; |
1286 | } | |
1287 | ||
1288 | static int syslog_print(char __user *buf, int size) | |
1289 | { | |
1290 | char *text; | |
62e32ac3 | 1291 | struct printk_log *msg; |
116e90b2 | 1292 | int len = 0; |
7ff9554b | 1293 | |
70498253 | 1294 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1295 | if (!text) |
1296 | return -ENOMEM; | |
1297 | ||
116e90b2 JB |
1298 | while (size > 0) { |
1299 | size_t n; | |
eb02dac9 | 1300 | size_t skip; |
116e90b2 | 1301 | |
de6fcbdb | 1302 | logbuf_lock_irq(); |
116e90b2 JB |
1303 | if (syslog_seq < log_first_seq) { |
1304 | /* messages are gone, move to first one */ | |
1305 | syslog_seq = log_first_seq; | |
1306 | syslog_idx = log_first_idx; | |
eb02dac9 | 1307 | syslog_partial = 0; |
116e90b2 JB |
1308 | } |
1309 | if (syslog_seq == log_next_seq) { | |
de6fcbdb | 1310 | logbuf_unlock_irq(); |
116e90b2 JB |
1311 | break; |
1312 | } | |
eb02dac9 KS |
1313 | |
1314 | skip = syslog_partial; | |
116e90b2 | 1315 | msg = log_from_idx(syslog_idx); |
5aa068ea | 1316 | n = msg_print_text(msg, true, text, LOG_LINE_MAX + PREFIX_MAX); |
eb02dac9 KS |
1317 | if (n - syslog_partial <= size) { |
1318 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1319 | syslog_idx = log_next(syslog_idx); |
1320 | syslog_seq++; | |
eb02dac9 KS |
1321 | n -= syslog_partial; |
1322 | syslog_partial = 0; | |
1323 | } else if (!len){ | |
1324 | /* partial read(), remember position */ | |
1325 | n = size; | |
1326 | syslog_partial += n; | |
116e90b2 JB |
1327 | } else |
1328 | n = 0; | |
de6fcbdb | 1329 | logbuf_unlock_irq(); |
116e90b2 JB |
1330 | |
1331 | if (!n) | |
1332 | break; | |
1333 | ||
eb02dac9 | 1334 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1335 | if (!len) |
1336 | len = -EFAULT; | |
1337 | break; | |
1338 | } | |
eb02dac9 KS |
1339 | |
1340 | len += n; | |
1341 | size -= n; | |
1342 | buf += n; | |
7ff9554b | 1343 | } |
7ff9554b KS |
1344 | |
1345 | kfree(text); | |
1346 | return len; | |
1347 | } | |
1348 | ||
1349 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1350 | { | |
1351 | char *text; | |
1352 | int len = 0; | |
1353 | ||
70498253 | 1354 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1355 | if (!text) |
1356 | return -ENOMEM; | |
1357 | ||
de6fcbdb | 1358 | logbuf_lock_irq(); |
7ff9554b KS |
1359 | if (buf) { |
1360 | u64 next_seq; | |
1361 | u64 seq; | |
1362 | u32 idx; | |
1363 | ||
7ff9554b KS |
1364 | /* |
1365 | * Find first record that fits, including all following records, | |
1366 | * into the user-provided buffer for this dump. | |
e2ae715d | 1367 | */ |
7ff9554b KS |
1368 | seq = clear_seq; |
1369 | idx = clear_idx; | |
1370 | while (seq < log_next_seq) { | |
62e32ac3 | 1371 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1372 | |
5aa068ea | 1373 | len += msg_print_text(msg, true, NULL, 0); |
7ff9554b KS |
1374 | idx = log_next(idx); |
1375 | seq++; | |
1376 | } | |
e2ae715d KS |
1377 | |
1378 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1379 | seq = clear_seq; |
1380 | idx = clear_idx; | |
1381 | while (len > size && seq < log_next_seq) { | |
62e32ac3 | 1382 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1383 | |
5aa068ea | 1384 | len -= msg_print_text(msg, true, NULL, 0); |
7ff9554b KS |
1385 | idx = log_next(idx); |
1386 | seq++; | |
1387 | } | |
1388 | ||
e2ae715d | 1389 | /* last message fitting into this dump */ |
7ff9554b KS |
1390 | next_seq = log_next_seq; |
1391 | ||
1392 | len = 0; | |
1393 | while (len >= 0 && seq < next_seq) { | |
62e32ac3 | 1394 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1395 | int textlen; |
1396 | ||
5aa068ea | 1397 | textlen = msg_print_text(msg, true, text, |
70498253 | 1398 | LOG_LINE_MAX + PREFIX_MAX); |
7ff9554b KS |
1399 | if (textlen < 0) { |
1400 | len = textlen; | |
1401 | break; | |
1402 | } | |
1403 | idx = log_next(idx); | |
1404 | seq++; | |
1405 | ||
de6fcbdb | 1406 | logbuf_unlock_irq(); |
7ff9554b KS |
1407 | if (copy_to_user(buf + len, text, textlen)) |
1408 | len = -EFAULT; | |
1409 | else | |
1410 | len += textlen; | |
de6fcbdb | 1411 | logbuf_lock_irq(); |
7ff9554b KS |
1412 | |
1413 | if (seq < log_first_seq) { | |
1414 | /* messages are gone, move to next one */ | |
1415 | seq = log_first_seq; | |
1416 | idx = log_first_idx; | |
1417 | } | |
1418 | } | |
1419 | } | |
1420 | ||
1421 | if (clear) { | |
1422 | clear_seq = log_next_seq; | |
1423 | clear_idx = log_next_idx; | |
1424 | } | |
de6fcbdb | 1425 | logbuf_unlock_irq(); |
7ff9554b KS |
1426 | |
1427 | kfree(text); | |
1428 | return len; | |
1429 | } | |
1430 | ||
3ea4331c | 1431 | int do_syslog(int type, char __user *buf, int len, int source) |
1da177e4 | 1432 | { |
7ff9554b | 1433 | bool clear = false; |
a39d4a85 | 1434 | static int saved_console_loglevel = LOGLEVEL_DEFAULT; |
ee24aebf | 1435 | int error; |
1da177e4 | 1436 | |
3ea4331c | 1437 | error = check_syslog_permissions(type, source); |
ee24aebf LT |
1438 | if (error) |
1439 | goto out; | |
12b3052c | 1440 | |
1da177e4 | 1441 | switch (type) { |
d78ca3cd | 1442 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1443 | break; |
d78ca3cd | 1444 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1445 | break; |
d78ca3cd | 1446 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1447 | error = -EINVAL; |
1448 | if (!buf || len < 0) | |
1449 | goto out; | |
1450 | error = 0; | |
1451 | if (!len) | |
1452 | goto out; | |
1453 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1454 | error = -EFAULT; | |
1455 | goto out; | |
1456 | } | |
40dc5651 | 1457 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1458 | syslog_seq != log_next_seq); |
cb424ffe | 1459 | if (error) |
1da177e4 | 1460 | goto out; |
7ff9554b | 1461 | error = syslog_print(buf, len); |
1da177e4 | 1462 | break; |
d78ca3cd KC |
1463 | /* Read/clear last kernel messages */ |
1464 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1465 | clear = true; |
1da177e4 | 1466 | /* FALL THRU */ |
d78ca3cd KC |
1467 | /* Read last kernel messages */ |
1468 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1469 | error = -EINVAL; |
1470 | if (!buf || len < 0) | |
1471 | goto out; | |
1472 | error = 0; | |
1473 | if (!len) | |
1474 | goto out; | |
1475 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1476 | error = -EFAULT; | |
1477 | goto out; | |
1478 | } | |
7ff9554b | 1479 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1480 | break; |
d78ca3cd KC |
1481 | /* Clear ring buffer */ |
1482 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1483 | syslog_print_all(NULL, 0, true); |
4661e356 | 1484 | break; |
d78ca3cd KC |
1485 | /* Disable logging to console */ |
1486 | case SYSLOG_ACTION_CONSOLE_OFF: | |
a39d4a85 | 1487 | if (saved_console_loglevel == LOGLEVEL_DEFAULT) |
1aaad49e | 1488 | saved_console_loglevel = console_loglevel; |
1da177e4 LT |
1489 | console_loglevel = minimum_console_loglevel; |
1490 | break; | |
d78ca3cd KC |
1491 | /* Enable logging to console */ |
1492 | case SYSLOG_ACTION_CONSOLE_ON: | |
a39d4a85 | 1493 | if (saved_console_loglevel != LOGLEVEL_DEFAULT) { |
1aaad49e | 1494 | console_loglevel = saved_console_loglevel; |
a39d4a85 | 1495 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1aaad49e | 1496 | } |
1da177e4 | 1497 | break; |
d78ca3cd KC |
1498 | /* Set level of messages printed to console */ |
1499 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1500 | error = -EINVAL; |
1501 | if (len < 1 || len > 8) | |
1502 | goto out; | |
1503 | if (len < minimum_console_loglevel) | |
1504 | len = minimum_console_loglevel; | |
1505 | console_loglevel = len; | |
1aaad49e | 1506 | /* Implicitly re-enable logging to console */ |
a39d4a85 | 1507 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1da177e4 LT |
1508 | error = 0; |
1509 | break; | |
d78ca3cd KC |
1510 | /* Number of chars in the log buffer */ |
1511 | case SYSLOG_ACTION_SIZE_UNREAD: | |
de6fcbdb | 1512 | logbuf_lock_irq(); |
7ff9554b KS |
1513 | if (syslog_seq < log_first_seq) { |
1514 | /* messages are gone, move to first one */ | |
1515 | syslog_seq = log_first_seq; | |
1516 | syslog_idx = log_first_idx; | |
eb02dac9 | 1517 | syslog_partial = 0; |
7ff9554b | 1518 | } |
3ea4331c | 1519 | if (source == SYSLOG_FROM_PROC) { |
7ff9554b KS |
1520 | /* |
1521 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1522 | * for pending data, not the size; return the count of | |
1523 | * records, not the length. | |
1524 | */ | |
e97e1267 | 1525 | error = log_next_seq - syslog_seq; |
7ff9554b | 1526 | } else { |
5becfb1d KS |
1527 | u64 seq = syslog_seq; |
1528 | u32 idx = syslog_idx; | |
7ff9554b KS |
1529 | |
1530 | error = 0; | |
7ff9554b | 1531 | while (seq < log_next_seq) { |
62e32ac3 | 1532 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1533 | |
5aa068ea | 1534 | error += msg_print_text(msg, true, NULL, 0); |
7ff9554b KS |
1535 | idx = log_next(idx); |
1536 | seq++; | |
1537 | } | |
eb02dac9 | 1538 | error -= syslog_partial; |
7ff9554b | 1539 | } |
de6fcbdb | 1540 | logbuf_unlock_irq(); |
1da177e4 | 1541 | break; |
d78ca3cd KC |
1542 | /* Size of the log buffer */ |
1543 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1544 | error = log_buf_len; |
1545 | break; | |
1546 | default: | |
1547 | error = -EINVAL; | |
1548 | break; | |
1549 | } | |
1550 | out: | |
1551 | return error; | |
1552 | } | |
1553 | ||
1e7bfb21 | 1554 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1555 | { |
637241a9 | 1556 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1557 | } |
1558 | ||
1da177e4 LT |
1559 | /* |
1560 | * Call the console drivers, asking them to write out | |
1561 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1562 | * The console_lock must be held. |
1da177e4 | 1563 | */ |
d9c23523 | 1564 | static void call_console_drivers(const char *ext_text, size_t ext_len, |
6fe29354 | 1565 | const char *text, size_t len) |
1da177e4 | 1566 | { |
7ff9554b | 1567 | struct console *con; |
1da177e4 | 1568 | |
fc98c3c8 | 1569 | trace_console_rcuidle(text, len); |
7ff9554b | 1570 | |
7ff9554b KS |
1571 | if (!console_drivers) |
1572 | return; | |
1573 | ||
1574 | for_each_console(con) { | |
1575 | if (exclusive_console && con != exclusive_console) | |
1576 | continue; | |
1577 | if (!(con->flags & CON_ENABLED)) | |
1578 | continue; | |
1579 | if (!con->write) | |
1580 | continue; | |
1581 | if (!cpu_online(smp_processor_id()) && | |
1582 | !(con->flags & CON_ANYTIME)) | |
1583 | continue; | |
6fe29354 TH |
1584 | if (con->flags & CON_EXTENDED) |
1585 | con->write(con, ext_text, ext_len); | |
1586 | else | |
1587 | con->write(con, text, len); | |
7ff9554b | 1588 | } |
1da177e4 LT |
1589 | } |
1590 | ||
af91322e DY |
1591 | int printk_delay_msec __read_mostly; |
1592 | ||
1593 | static inline void printk_delay(void) | |
1594 | { | |
1595 | if (unlikely(printk_delay_msec)) { | |
1596 | int m = printk_delay_msec; | |
1597 | ||
1598 | while (m--) { | |
1599 | mdelay(1); | |
1600 | touch_nmi_watchdog(); | |
1601 | } | |
1602 | } | |
1603 | } | |
1604 | ||
084681d1 KS |
1605 | /* |
1606 | * Continuation lines are buffered, and not committed to the record buffer | |
1607 | * until the line is complete, or a race forces it. The line fragments | |
1608 | * though, are printed immediately to the consoles to ensure everything has | |
1609 | * reached the console in case of a kernel crash. | |
1610 | */ | |
1611 | static struct cont { | |
1612 | char buf[LOG_LINE_MAX]; | |
1613 | size_t len; /* length == 0 means unused buffer */ | |
084681d1 KS |
1614 | struct task_struct *owner; /* task of first print*/ |
1615 | u64 ts_nsec; /* time of first print */ | |
1616 | u8 level; /* log level of first message */ | |
0b90fec3 | 1617 | u8 facility; /* log facility of first message */ |
eab07260 | 1618 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1619 | } cont; |
1620 | ||
5e467652 | 1621 | static void cont_flush(void) |
084681d1 | 1622 | { |
084681d1 KS |
1623 | if (cont.len == 0) |
1624 | return; | |
5c2992ee LT |
1625 | |
1626 | log_store(cont.facility, cont.level, cont.flags, cont.ts_nsec, | |
1627 | NULL, 0, cont.buf, cont.len); | |
1628 | cont.len = 0; | |
084681d1 KS |
1629 | } |
1630 | ||
5e467652 | 1631 | static bool cont_add(int facility, int level, enum log_flags flags, const char *text, size_t len) |
084681d1 | 1632 | { |
6fe29354 TH |
1633 | /* |
1634 | * If ext consoles are present, flush and skip in-kernel | |
1635 | * continuation. See nr_ext_console_drivers definition. Also, if | |
1636 | * the line gets too long, split it up in separate records. | |
1637 | */ | |
1638 | if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) { | |
5e467652 | 1639 | cont_flush(); |
084681d1 KS |
1640 | return false; |
1641 | } | |
1642 | ||
1643 | if (!cont.len) { | |
1644 | cont.facility = facility; | |
1645 | cont.level = level; | |
1646 | cont.owner = current; | |
1647 | cont.ts_nsec = local_clock(); | |
5e467652 | 1648 | cont.flags = flags; |
084681d1 KS |
1649 | } |
1650 | ||
1651 | memcpy(cont.buf + cont.len, text, len); | |
1652 | cont.len += len; | |
eab07260 | 1653 | |
5e467652 LT |
1654 | // The original flags come from the first line, |
1655 | // but later continuations can add a newline. | |
1656 | if (flags & LOG_NEWLINE) { | |
1657 | cont.flags |= LOG_NEWLINE; | |
1658 | cont_flush(); | |
1659 | } | |
1660 | ||
eab07260 | 1661 | if (cont.len > (sizeof(cont.buf) * 80) / 100) |
5e467652 | 1662 | cont_flush(); |
eab07260 | 1663 | |
084681d1 KS |
1664 | return true; |
1665 | } | |
1666 | ||
c362c7ff LT |
1667 | 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) |
1668 | { | |
c362c7ff | 1669 | /* |
5e467652 LT |
1670 | * If an earlier line was buffered, and we're a continuation |
1671 | * write from the same process, try to add it to the buffer. | |
c362c7ff LT |
1672 | */ |
1673 | if (cont.len) { | |
5e467652 LT |
1674 | if (cont.owner == current && (lflags & LOG_CONT)) { |
1675 | if (cont_add(facility, level, lflags, text, text_len)) | |
1676 | return text_len; | |
1677 | } | |
1678 | /* Otherwise, make sure it's flushed */ | |
1679 | cont_flush(); | |
1680 | } | |
c362c7ff | 1681 | |
8835ca59 LT |
1682 | /* Skip empty continuation lines that couldn't be added - they just flush */ |
1683 | if (!text_len && (lflags & LOG_CONT)) | |
1684 | return 0; | |
1685 | ||
5e467652 LT |
1686 | /* If it doesn't end in a newline, try to buffer the current line */ |
1687 | if (!(lflags & LOG_NEWLINE)) { | |
1688 | if (cont_add(facility, level, lflags, text, text_len)) | |
c362c7ff LT |
1689 | return text_len; |
1690 | } | |
1691 | ||
5e467652 | 1692 | /* Store it in the record log */ |
c362c7ff LT |
1693 | return log_store(facility, level, lflags, 0, dict, dictlen, text, text_len); |
1694 | } | |
1695 | ||
7ff9554b KS |
1696 | asmlinkage int vprintk_emit(int facility, int level, |
1697 | const char *dict, size_t dictlen, | |
1698 | const char *fmt, va_list args) | |
1da177e4 | 1699 | { |
7ff9554b KS |
1700 | static char textbuf[LOG_LINE_MAX]; |
1701 | char *text = textbuf; | |
458df9fd | 1702 | size_t text_len = 0; |
5becfb1d | 1703 | enum log_flags lflags = 0; |
ac60ad74 | 1704 | unsigned long flags; |
7ff9554b | 1705 | int printed_len = 0; |
458df9fd | 1706 | bool in_sched = false; |
608873ca | 1707 | |
a39d4a85 JP |
1708 | if (level == LOGLEVEL_SCHED) { |
1709 | level = LOGLEVEL_DEFAULT; | |
458df9fd SR |
1710 | in_sched = true; |
1711 | } | |
1da177e4 | 1712 | |
2fa72c8f | 1713 | boot_delay_msec(level); |
af91322e | 1714 | printk_delay(); |
bfe8df3d | 1715 | |
a8199371 | 1716 | /* This stops the holder of console_sem just where we want him */ |
de6fcbdb | 1717 | logbuf_lock_irqsave(flags); |
7ff9554b KS |
1718 | /* |
1719 | * The printf needs to come first; we need the syslog | |
1720 | * prefix which might be passed-in as a parameter. | |
1721 | */ | |
98e35f58 | 1722 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1723 | |
7ff9554b | 1724 | /* mark and strip a trailing newline */ |
c313af14 KS |
1725 | if (text_len && text[text_len-1] == '\n') { |
1726 | text_len--; | |
5becfb1d | 1727 | lflags |= LOG_NEWLINE; |
7ff9554b | 1728 | } |
9d90c8d9 | 1729 | |
088a52aa JP |
1730 | /* strip kernel syslog prefix and extract log level or control flags */ |
1731 | if (facility == 0) { | |
4bcc595c | 1732 | int kern_level; |
088a52aa | 1733 | |
4bcc595c | 1734 | while ((kern_level = printk_get_level(text)) != 0) { |
088a52aa JP |
1735 | switch (kern_level) { |
1736 | case '0' ... '7': | |
a39d4a85 | 1737 | if (level == LOGLEVEL_DEFAULT) |
088a52aa | 1738 | level = kern_level - '0'; |
a39d4a85 | 1739 | /* fallthrough */ |
088a52aa JP |
1740 | case 'd': /* KERN_DEFAULT */ |
1741 | lflags |= LOG_PREFIX; | |
4bcc595c LT |
1742 | break; |
1743 | case 'c': /* KERN_CONT */ | |
1744 | lflags |= LOG_CONT; | |
088a52aa | 1745 | } |
4bcc595c LT |
1746 | |
1747 | text_len -= 2; | |
1748 | text += 2; | |
5fd29d6c LT |
1749 | } |
1750 | } | |
1751 | ||
a39d4a85 | 1752 | if (level == LOGLEVEL_DEFAULT) |
c313af14 | 1753 | level = default_message_loglevel; |
9d90c8d9 | 1754 | |
5becfb1d KS |
1755 | if (dict) |
1756 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1757 | |
c362c7ff | 1758 | printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len); |
1da177e4 | 1759 | |
de6fcbdb | 1760 | logbuf_unlock_irqrestore(flags); |
939f04be | 1761 | |
458df9fd | 1762 | /* If called from the scheduler, we can not call up(). */ |
d18bbc21 AM |
1763 | if (!in_sched) { |
1764 | /* | |
1765 | * Try to acquire and then immediately release the console | |
1766 | * semaphore. The release will print out buffers and wake up | |
1767 | * /dev/kmsg and syslog() users. | |
1768 | */ | |
a8199371 | 1769 | if (console_trylock()) |
d18bbc21 AM |
1770 | console_unlock(); |
1771 | } | |
76a8ad29 | 1772 | |
1da177e4 LT |
1773 | return printed_len; |
1774 | } | |
7ff9554b KS |
1775 | EXPORT_SYMBOL(vprintk_emit); |
1776 | ||
1777 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1778 | { | |
bd66a892 | 1779 | return vprintk_func(fmt, args); |
7ff9554b | 1780 | } |
1da177e4 LT |
1781 | EXPORT_SYMBOL(vprintk); |
1782 | ||
7ff9554b KS |
1783 | asmlinkage int printk_emit(int facility, int level, |
1784 | const char *dict, size_t dictlen, | |
1785 | const char *fmt, ...) | |
1786 | { | |
1787 | va_list args; | |
1788 | int r; | |
1789 | ||
1790 | va_start(args, fmt); | |
1791 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1792 | va_end(args); | |
1793 | ||
1794 | return r; | |
1795 | } | |
1796 | EXPORT_SYMBOL(printk_emit); | |
1797 | ||
a0cba217 | 1798 | int vprintk_default(const char *fmt, va_list args) |
afdc34a3 SRRH |
1799 | { |
1800 | int r; | |
1801 | ||
1802 | #ifdef CONFIG_KGDB_KDB | |
34aaff40 PM |
1803 | /* Allow to pass printk() to kdb but avoid a recursion. */ |
1804 | if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0)) { | |
f7d4ca8b | 1805 | r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); |
afdc34a3 SRRH |
1806 | return r; |
1807 | } | |
1808 | #endif | |
a0cba217 | 1809 | r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
afdc34a3 SRRH |
1810 | |
1811 | return r; | |
1812 | } | |
1813 | EXPORT_SYMBOL_GPL(vprintk_default); | |
1814 | ||
7ff9554b KS |
1815 | /** |
1816 | * printk - print a kernel message | |
1817 | * @fmt: format string | |
1818 | * | |
1819 | * This is printk(). It can be called from any context. We want it to work. | |
1820 | * | |
1821 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1822 | * output and call the console drivers. If we fail to get the semaphore, we | |
1823 | * place the output into the log buffer and return. The current holder of | |
1824 | * the console_sem will notice the new output in console_unlock(); and will | |
1825 | * send it to the consoles before releasing the lock. | |
1826 | * | |
1827 | * One effect of this deferred printing is that code which calls printk() and | |
1828 | * then changes console_loglevel may break. This is because console_loglevel | |
1829 | * is inspected when the actual printing occurs. | |
1830 | * | |
1831 | * See also: | |
1832 | * printf(3) | |
1833 | * | |
1834 | * See the vsnprintf() documentation for format string extensions over C99. | |
1835 | */ | |
722a9f92 | 1836 | asmlinkage __visible int printk(const char *fmt, ...) |
7ff9554b KS |
1837 | { |
1838 | va_list args; | |
1839 | int r; | |
1840 | ||
7ff9554b | 1841 | va_start(args, fmt); |
a0cba217 | 1842 | r = vprintk_func(fmt, args); |
7ff9554b KS |
1843 | va_end(args); |
1844 | ||
1845 | return r; | |
1846 | } | |
1847 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1848 | |
96efedf1 | 1849 | #else /* CONFIG_PRINTK */ |
d59745ce | 1850 | |
70498253 KS |
1851 | #define LOG_LINE_MAX 0 |
1852 | #define PREFIX_MAX 0 | |
249771b8 | 1853 | |
96efedf1 KS |
1854 | static u64 syslog_seq; |
1855 | static u32 syslog_idx; | |
eab07260 KS |
1856 | static u64 console_seq; |
1857 | static u32 console_idx; | |
96efedf1 KS |
1858 | static u64 log_first_seq; |
1859 | static u32 log_first_idx; | |
1860 | static u64 log_next_seq; | |
6fe29354 TH |
1861 | static char *log_text(const struct printk_log *msg) { return NULL; } |
1862 | static char *log_dict(const struct printk_log *msg) { return NULL; } | |
62e32ac3 | 1863 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1864 | static u32 log_next(u32 idx) { return 0; } |
6fe29354 | 1865 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
5aa068ea LT |
1866 | struct printk_log *msg, |
1867 | u64 seq) { return 0; } | |
6fe29354 TH |
1868 | static ssize_t msg_print_ext_body(char *buf, size_t size, |
1869 | char *dict, size_t dict_len, | |
1870 | char *text, size_t text_len) { return 0; } | |
d9c23523 | 1871 | static void call_console_drivers(const char *ext_text, size_t ext_len, |
6fe29354 | 1872 | const char *text, size_t len) {} |
5aa068ea | 1873 | static size_t msg_print_text(const struct printk_log *msg, |
5becfb1d | 1874 | bool syslog, char *buf, size_t size) { return 0; } |
cf775444 | 1875 | static bool suppress_message_printing(int level) { return false; } |
d59745ce | 1876 | |
7f3a781d | 1877 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1878 | |
d0380e6c TG |
1879 | #ifdef CONFIG_EARLY_PRINTK |
1880 | struct console *early_console; | |
1881 | ||
722a9f92 | 1882 | asmlinkage __visible void early_printk(const char *fmt, ...) |
d0380e6c TG |
1883 | { |
1884 | va_list ap; | |
1dc6244b JP |
1885 | char buf[512]; |
1886 | int n; | |
1887 | ||
1888 | if (!early_console) | |
1889 | return; | |
d0380e6c TG |
1890 | |
1891 | va_start(ap, fmt); | |
1dc6244b | 1892 | n = vscnprintf(buf, sizeof(buf), fmt, ap); |
d0380e6c | 1893 | va_end(ap); |
1dc6244b JP |
1894 | |
1895 | early_console->write(early_console, buf, n); | |
d0380e6c TG |
1896 | } |
1897 | #endif | |
1898 | ||
f7511d5f ST |
1899 | static int __add_preferred_console(char *name, int idx, char *options, |
1900 | char *brl_options) | |
1901 | { | |
1902 | struct console_cmdline *c; | |
1903 | int i; | |
1904 | ||
1905 | /* | |
1906 | * See if this tty is not yet registered, and | |
1907 | * if we have a slot free. | |
1908 | */ | |
cf39bf58 | 1909 | for (i = 0, c = console_cmdline; i < console_cmdline_cnt; i++, c++) { |
23475408 | 1910 | if (strcmp(c->name, name) == 0 && c->index == idx) { |
cf39bf58 AM |
1911 | if (brl_options) |
1912 | return 0; | |
1913 | ||
1914 | /* | |
1915 | * Maintain an invariant that will help to find if | |
1916 | * the matching console is preferred, see | |
1917 | * register_console(): | |
1918 | * | |
1919 | * The last non-braille console is always | |
1920 | * the preferred one. | |
1921 | */ | |
1922 | if (i != console_cmdline_cnt - 1) | |
1923 | swap(console_cmdline[i], | |
1924 | console_cmdline[console_cmdline_cnt - 1]); | |
1925 | ||
1926 | preferred_console = console_cmdline_cnt - 1; | |
1927 | ||
23475408 | 1928 | return 0; |
f7511d5f | 1929 | } |
23475408 | 1930 | } |
f7511d5f ST |
1931 | if (i == MAX_CMDLINECONSOLES) |
1932 | return -E2BIG; | |
1933 | if (!brl_options) | |
ad86ee2b | 1934 | preferred_console = i; |
f7511d5f ST |
1935 | strlcpy(c->name, name, sizeof(c->name)); |
1936 | c->options = options; | |
bbeddf52 JP |
1937 | braille_set_options(c, brl_options); |
1938 | ||
f7511d5f | 1939 | c->index = idx; |
cf39bf58 | 1940 | console_cmdline_cnt++; |
f7511d5f ST |
1941 | return 0; |
1942 | } | |
2ea1c539 | 1943 | /* |
0b90fec3 AE |
1944 | * Set up a console. Called via do_early_param() in init/main.c |
1945 | * for each "console=" parameter in the boot command line. | |
2ea1c539 JB |
1946 | */ |
1947 | static int __init console_setup(char *str) | |
1948 | { | |
0b90fec3 | 1949 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */ |
f7511d5f | 1950 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1951 | int idx; |
1952 | ||
bbeddf52 JP |
1953 | if (_braille_console_setup(&str, &brl_options)) |
1954 | return 1; | |
f7511d5f | 1955 | |
2ea1c539 JB |
1956 | /* |
1957 | * Decode str into name, index, options. | |
1958 | */ | |
1959 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1960 | strcpy(buf, "ttyS"); |
1961 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1962 | } else { |
eaa944af | 1963 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1964 | } |
eaa944af | 1965 | buf[sizeof(buf) - 1] = 0; |
249771b8 AE |
1966 | options = strchr(str, ','); |
1967 | if (options) | |
2ea1c539 JB |
1968 | *(options++) = 0; |
1969 | #ifdef __sparc__ | |
1970 | if (!strcmp(str, "ttya")) | |
eaa944af | 1971 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1972 | if (!strcmp(str, "ttyb")) |
eaa944af | 1973 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1974 | #endif |
eaa944af | 1975 | for (s = buf; *s; s++) |
249771b8 | 1976 | if (isdigit(*s) || *s == ',') |
2ea1c539 JB |
1977 | break; |
1978 | idx = simple_strtoul(s, NULL, 10); | |
1979 | *s = 0; | |
1980 | ||
f7511d5f | 1981 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1982 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1983 | return 1; |
1984 | } | |
1985 | __setup("console=", console_setup); | |
1986 | ||
3c0547ba MM |
1987 | /** |
1988 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1989 | * @name: device name |
1990 | * @idx: device index | |
1991 | * @options: options for this console | |
3c0547ba MM |
1992 | * |
1993 | * The last preferred console added will be used for kernel messages | |
1994 | * and stdin/out/err for init. Normally this is used by console_setup | |
1995 | * above to handle user-supplied console arguments; however it can also | |
1996 | * be used by arch-specific code either to override the user or more | |
1997 | * commonly to provide a default console (ie from PROM variables) when | |
1998 | * the user has not supplied one. | |
1999 | */ | |
fb445ee5 | 2000 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 2001 | { |
f7511d5f | 2002 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
2003 | } |
2004 | ||
d25d9fec | 2005 | bool console_suspend_enabled = true; |
8f4ce8c3 AS |
2006 | EXPORT_SYMBOL(console_suspend_enabled); |
2007 | ||
2008 | static int __init console_suspend_disable(char *str) | |
2009 | { | |
d25d9fec | 2010 | console_suspend_enabled = false; |
8f4ce8c3 AS |
2011 | return 1; |
2012 | } | |
2013 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
2014 | module_param_named(console_suspend, console_suspend_enabled, |
2015 | bool, S_IRUGO | S_IWUSR); | |
2016 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
2017 | " and hibernate operations"); | |
8f4ce8c3 | 2018 | |
557240b4 LT |
2019 | /** |
2020 | * suspend_console - suspend the console subsystem | |
2021 | * | |
2022 | * This disables printk() while we go into suspend states | |
2023 | */ | |
2024 | void suspend_console(void) | |
2025 | { | |
8f4ce8c3 AS |
2026 | if (!console_suspend_enabled) |
2027 | return; | |
0d63081d | 2028 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 2029 | console_lock(); |
557240b4 | 2030 | console_suspended = 1; |
bd8d7cf5 | 2031 | up_console_sem(); |
557240b4 LT |
2032 | } |
2033 | ||
2034 | void resume_console(void) | |
2035 | { | |
8f4ce8c3 AS |
2036 | if (!console_suspend_enabled) |
2037 | return; | |
bd8d7cf5 | 2038 | down_console_sem(); |
557240b4 | 2039 | console_suspended = 0; |
ac751efa | 2040 | console_unlock(); |
557240b4 LT |
2041 | } |
2042 | ||
034260d6 KC |
2043 | /** |
2044 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
90b14889 | 2045 | * @cpu: unused |
034260d6 KC |
2046 | * |
2047 | * If printk() is called from a CPU that is not online yet, the messages | |
64ca752d SS |
2048 | * will be printed on the console only if there are CON_ANYTIME consoles. |
2049 | * This function is called when a new CPU comes online (or fails to come | |
2050 | * up) or goes offline. | |
034260d6 | 2051 | */ |
90b14889 SAS |
2052 | static int console_cpu_notify(unsigned int cpu) |
2053 | { | |
f97960fb | 2054 | if (!cpuhp_tasks_frozen) { |
64ca752d SS |
2055 | /* If trylock fails, someone else is doing the printing */ |
2056 | if (console_trylock()) | |
2057 | console_unlock(); | |
034260d6 | 2058 | } |
90b14889 | 2059 | return 0; |
034260d6 KC |
2060 | } |
2061 | ||
1da177e4 | 2062 | /** |
ac751efa | 2063 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2064 | * |
ac751efa | 2065 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2066 | * exclusive access to the console system and the console_drivers list. |
2067 | * | |
2068 | * Can sleep, returns nothing. | |
2069 | */ | |
ac751efa | 2070 | void console_lock(void) |
1da177e4 | 2071 | { |
6b898c07 DV |
2072 | might_sleep(); |
2073 | ||
bd8d7cf5 | 2074 | down_console_sem(); |
403f3075 AH |
2075 | if (console_suspended) |
2076 | return; | |
1da177e4 LT |
2077 | console_locked = 1; |
2078 | console_may_schedule = 1; | |
2079 | } | |
ac751efa | 2080 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2081 | |
ac751efa TH |
2082 | /** |
2083 | * console_trylock - try to lock the console system for exclusive use. | |
2084 | * | |
0b90fec3 AE |
2085 | * Try to acquire a lock which guarantees that the caller has exclusive |
2086 | * access to the console system and the console_drivers list. | |
ac751efa TH |
2087 | * |
2088 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2089 | */ | |
2090 | int console_trylock(void) | |
1da177e4 | 2091 | { |
bd8d7cf5 | 2092 | if (down_trylock_console_sem()) |
ac751efa | 2093 | return 0; |
403f3075 | 2094 | if (console_suspended) { |
bd8d7cf5 | 2095 | up_console_sem(); |
ac751efa | 2096 | return 0; |
403f3075 | 2097 | } |
1da177e4 | 2098 | console_locked = 1; |
6b97a20d SS |
2099 | /* |
2100 | * When PREEMPT_COUNT disabled we can't reliably detect if it's | |
2101 | * safe to schedule (e.g. calling printk while holding a spin_lock), | |
2102 | * because preempt_disable()/preempt_enable() are just barriers there | |
2103 | * and preempt_count() is always 0. | |
2104 | * | |
2105 | * RCU read sections have a separate preemption counter when | |
2106 | * PREEMPT_RCU enabled thus we must take extra care and check | |
2107 | * rcu_preempt_depth(), otherwise RCU read sections modify | |
2108 | * preempt_count(). | |
2109 | */ | |
2110 | console_may_schedule = !oops_in_progress && | |
2111 | preemptible() && | |
2112 | !rcu_preempt_depth(); | |
ac751efa | 2113 | return 1; |
1da177e4 | 2114 | } |
ac751efa | 2115 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2116 | |
2117 | int is_console_locked(void) | |
2118 | { | |
2119 | return console_locked; | |
2120 | } | |
1da177e4 | 2121 | |
a8199371 SS |
2122 | /* |
2123 | * Check if we have any console that is capable of printing while cpu is | |
2124 | * booting or shutting down. Requires console_sem. | |
2125 | */ | |
2126 | static int have_callable_console(void) | |
2127 | { | |
2128 | struct console *con; | |
2129 | ||
2130 | for_each_console(con) | |
adaf6590 SS |
2131 | if ((con->flags & CON_ENABLED) && |
2132 | (con->flags & CON_ANYTIME)) | |
a8199371 SS |
2133 | return 1; |
2134 | ||
2135 | return 0; | |
2136 | } | |
2137 | ||
2138 | /* | |
2139 | * Can we actually use the console at this time on this cpu? | |
2140 | * | |
2141 | * Console drivers may assume that per-cpu resources have been allocated. So | |
2142 | * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't | |
2143 | * call them until this CPU is officially up. | |
2144 | */ | |
2145 | static inline int can_use_console(void) | |
2146 | { | |
2147 | return cpu_online(raw_smp_processor_id()) || have_callable_console(); | |
2148 | } | |
2149 | ||
1da177e4 | 2150 | /** |
ac751efa | 2151 | * console_unlock - unlock the console system |
1da177e4 | 2152 | * |
ac751efa | 2153 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2154 | * and the console driver list. |
2155 | * | |
ac751efa TH |
2156 | * While the console_lock was held, console output may have been buffered |
2157 | * by printk(). If this is the case, console_unlock(); emits | |
2158 | * the output prior to releasing the lock. | |
1da177e4 | 2159 | * |
7f3a781d | 2160 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2161 | * |
ac751efa | 2162 | * console_unlock(); may be called from any context. |
1da177e4 | 2163 | */ |
ac751efa | 2164 | void console_unlock(void) |
1da177e4 | 2165 | { |
6fe29354 | 2166 | static char ext_text[CONSOLE_EXT_LOG_MAX]; |
70498253 | 2167 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2168 | static u64 seen_seq; |
1da177e4 | 2169 | unsigned long flags; |
7ff9554b | 2170 | bool wake_klogd = false; |
8d91f8b1 | 2171 | bool do_cond_resched, retry; |
1da177e4 | 2172 | |
557240b4 | 2173 | if (console_suspended) { |
bd8d7cf5 | 2174 | up_console_sem(); |
557240b4 LT |
2175 | return; |
2176 | } | |
78944e54 | 2177 | |
8d91f8b1 | 2178 | /* |
257ab443 | 2179 | * Console drivers are called with interrupts disabled, so |
8d91f8b1 TH |
2180 | * @console_may_schedule should be cleared before; however, we may |
2181 | * end up dumping a lot of lines, for example, if called from | |
2182 | * console registration path, and should invoke cond_resched() | |
2183 | * between lines if allowable. Not doing so can cause a very long | |
2184 | * scheduling stall on a slow console leading to RCU stall and | |
2185 | * softlockup warnings which exacerbate the issue with more | |
2186 | * messages practically incapacitating the system. | |
257ab443 PM |
2187 | * |
2188 | * console_trylock() is not able to detect the preemptive | |
2189 | * context reliably. Therefore the value must be stored before | |
2190 | * and cleared after the the "again" goto label. | |
8d91f8b1 TH |
2191 | */ |
2192 | do_cond_resched = console_may_schedule; | |
257ab443 | 2193 | again: |
78944e54 AD |
2194 | console_may_schedule = 0; |
2195 | ||
a8199371 SS |
2196 | /* |
2197 | * We released the console_sem lock, so we need to recheck if | |
2198 | * cpu is online and (if not) is there at least one CON_ANYTIME | |
2199 | * console. | |
2200 | */ | |
2201 | if (!can_use_console()) { | |
2202 | console_locked = 0; | |
2203 | up_console_sem(); | |
2204 | return; | |
2205 | } | |
2206 | ||
7ff9554b | 2207 | for (;;) { |
62e32ac3 | 2208 | struct printk_log *msg; |
6fe29354 | 2209 | size_t ext_len = 0; |
3ce9a7c0 | 2210 | size_t len; |
7ff9554b | 2211 | |
f975237b SS |
2212 | printk_safe_enter_irqsave(flags); |
2213 | raw_spin_lock(&logbuf_lock); | |
7ff9554b KS |
2214 | if (seen_seq != log_next_seq) { |
2215 | wake_klogd = true; | |
2216 | seen_seq = log_next_seq; | |
2217 | } | |
2218 | ||
2219 | if (console_seq < log_first_seq) { | |
84b5ec8a WD |
2220 | len = sprintf(text, "** %u printk messages dropped ** ", |
2221 | (unsigned)(log_first_seq - console_seq)); | |
2222 | ||
7ff9554b KS |
2223 | /* messages are gone, move to first one */ |
2224 | console_seq = log_first_seq; | |
2225 | console_idx = log_first_idx; | |
84b5ec8a WD |
2226 | } else { |
2227 | len = 0; | |
7ff9554b | 2228 | } |
084681d1 | 2229 | skip: |
7ff9554b KS |
2230 | if (console_seq == log_next_seq) |
2231 | break; | |
2232 | ||
2233 | msg = log_from_idx(console_idx); | |
d9c23523 | 2234 | if (suppress_message_printing(msg->level)) { |
084681d1 KS |
2235 | /* |
2236 | * Skip record we have buffered and already printed | |
cf775444 SS |
2237 | * directly to the console when we received it, and |
2238 | * record that has level above the console loglevel. | |
084681d1 KS |
2239 | */ |
2240 | console_idx = log_next(console_idx); | |
2241 | console_seq++; | |
2242 | goto skip; | |
2243 | } | |
649e6ee3 | 2244 | |
5aa068ea | 2245 | len += msg_print_text(msg, false, text + len, sizeof(text) - len); |
6fe29354 TH |
2246 | if (nr_ext_console_drivers) { |
2247 | ext_len = msg_print_ext_header(ext_text, | |
2248 | sizeof(ext_text), | |
5aa068ea | 2249 | msg, console_seq); |
6fe29354 TH |
2250 | ext_len += msg_print_ext_body(ext_text + ext_len, |
2251 | sizeof(ext_text) - ext_len, | |
2252 | log_dict(msg), msg->dict_len, | |
2253 | log_text(msg), msg->text_len); | |
2254 | } | |
7ff9554b KS |
2255 | console_idx = log_next(console_idx); |
2256 | console_seq++; | |
07354eb1 | 2257 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2258 | |
81d68a96 | 2259 | stop_critical_timings(); /* don't trace print latency */ |
d9c23523 | 2260 | call_console_drivers(ext_text, ext_len, text, len); |
81d68a96 | 2261 | start_critical_timings(); |
f975237b | 2262 | printk_safe_exit_irqrestore(flags); |
8d91f8b1 TH |
2263 | |
2264 | if (do_cond_resched) | |
2265 | cond_resched(); | |
1da177e4 LT |
2266 | } |
2267 | console_locked = 0; | |
fe3d8ad3 FT |
2268 | |
2269 | /* Release the exclusive_console once it is used */ | |
2270 | if (unlikely(exclusive_console)) | |
2271 | exclusive_console = NULL; | |
2272 | ||
07354eb1 | 2273 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2274 | |
bd8d7cf5 | 2275 | up_console_sem(); |
4f2a8d3c PZ |
2276 | |
2277 | /* | |
2278 | * Someone could have filled up the buffer again, so re-check if there's | |
2279 | * something to flush. In case we cannot trylock the console_sem again, | |
2280 | * there's a new owner and the console_unlock() from them will do the | |
2281 | * flush, no worries. | |
2282 | */ | |
07354eb1 | 2283 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2284 | retry = console_seq != log_next_seq; |
f975237b SS |
2285 | raw_spin_unlock(&logbuf_lock); |
2286 | printk_safe_exit_irqrestore(flags); | |
09dc3cf9 | 2287 | |
4f2a8d3c PZ |
2288 | if (retry && console_trylock()) |
2289 | goto again; | |
2290 | ||
e3e8a75d KK |
2291 | if (wake_klogd) |
2292 | wake_up_klogd(); | |
1da177e4 | 2293 | } |
ac751efa | 2294 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2295 | |
ddad86c2 MW |
2296 | /** |
2297 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2298 | * |
2299 | * If the console code is currently allowed to sleep, and | |
2300 | * if this CPU should yield the CPU to another task, do | |
2301 | * so here. | |
2302 | * | |
ac751efa | 2303 | * Must be called within console_lock();. |
1da177e4 LT |
2304 | */ |
2305 | void __sched console_conditional_schedule(void) | |
2306 | { | |
2307 | if (console_may_schedule) | |
2308 | cond_resched(); | |
2309 | } | |
2310 | EXPORT_SYMBOL(console_conditional_schedule); | |
2311 | ||
1da177e4 LT |
2312 | void console_unblank(void) |
2313 | { | |
2314 | struct console *c; | |
2315 | ||
2316 | /* | |
2317 | * console_unblank can no longer be called in interrupt context unless | |
2318 | * oops_in_progress is set to 1.. | |
2319 | */ | |
2320 | if (oops_in_progress) { | |
bd8d7cf5 | 2321 | if (down_trylock_console_sem() != 0) |
1da177e4 LT |
2322 | return; |
2323 | } else | |
ac751efa | 2324 | console_lock(); |
1da177e4 LT |
2325 | |
2326 | console_locked = 1; | |
2327 | console_may_schedule = 0; | |
4d091611 | 2328 | for_each_console(c) |
1da177e4 LT |
2329 | if ((c->flags & CON_ENABLED) && c->unblank) |
2330 | c->unblank(); | |
ac751efa | 2331 | console_unlock(); |
1da177e4 | 2332 | } |
1da177e4 | 2333 | |
8d91f8b1 TH |
2334 | /** |
2335 | * console_flush_on_panic - flush console content on panic | |
2336 | * | |
2337 | * Immediately output all pending messages no matter what. | |
2338 | */ | |
2339 | void console_flush_on_panic(void) | |
2340 | { | |
2341 | /* | |
2342 | * If someone else is holding the console lock, trylock will fail | |
2343 | * and may_schedule may be set. Ignore and proceed to unlock so | |
2344 | * that messages are flushed out. As this can be called from any | |
2345 | * context and we don't want to get preempted while flushing, | |
2346 | * ensure may_schedule is cleared. | |
2347 | */ | |
2348 | console_trylock(); | |
2349 | console_may_schedule = 0; | |
2350 | console_unlock(); | |
2351 | } | |
2352 | ||
1da177e4 LT |
2353 | /* |
2354 | * Return the console tty driver structure and its associated index | |
2355 | */ | |
2356 | struct tty_driver *console_device(int *index) | |
2357 | { | |
2358 | struct console *c; | |
2359 | struct tty_driver *driver = NULL; | |
2360 | ||
ac751efa | 2361 | console_lock(); |
4d091611 | 2362 | for_each_console(c) { |
1da177e4 LT |
2363 | if (!c->device) |
2364 | continue; | |
2365 | driver = c->device(c, index); | |
2366 | if (driver) | |
2367 | break; | |
2368 | } | |
ac751efa | 2369 | console_unlock(); |
1da177e4 LT |
2370 | return driver; |
2371 | } | |
2372 | ||
2373 | /* | |
2374 | * Prevent further output on the passed console device so that (for example) | |
2375 | * serial drivers can disable console output before suspending a port, and can | |
2376 | * re-enable output afterwards. | |
2377 | */ | |
2378 | void console_stop(struct console *console) | |
2379 | { | |
ac751efa | 2380 | console_lock(); |
1da177e4 | 2381 | console->flags &= ~CON_ENABLED; |
ac751efa | 2382 | console_unlock(); |
1da177e4 LT |
2383 | } |
2384 | EXPORT_SYMBOL(console_stop); | |
2385 | ||
2386 | void console_start(struct console *console) | |
2387 | { | |
ac751efa | 2388 | console_lock(); |
1da177e4 | 2389 | console->flags |= CON_ENABLED; |
ac751efa | 2390 | console_unlock(); |
1da177e4 LT |
2391 | } |
2392 | EXPORT_SYMBOL(console_start); | |
2393 | ||
7bf69395 FDN |
2394 | static int __read_mostly keep_bootcon; |
2395 | ||
2396 | static int __init keep_bootcon_setup(char *str) | |
2397 | { | |
2398 | keep_bootcon = 1; | |
27083bac | 2399 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2400 | |
2401 | return 0; | |
2402 | } | |
2403 | ||
2404 | early_param("keep_bootcon", keep_bootcon_setup); | |
2405 | ||
1da177e4 LT |
2406 | /* |
2407 | * The console driver calls this routine during kernel initialization | |
2408 | * to register the console printing procedure with printk() and to | |
2409 | * print any messages that were printed by the kernel before the | |
2410 | * console driver was initialized. | |
4d091611 RG |
2411 | * |
2412 | * This can happen pretty early during the boot process (because of | |
2413 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2414 | * of what kernel features are used - they may not be initialised yet. | |
2415 | * | |
2416 | * There are two types of consoles - bootconsoles (early_printk) and | |
2417 | * "real" consoles (everything which is not a bootconsole) which are | |
2418 | * handled differently. | |
2419 | * - Any number of bootconsoles can be registered at any time. | |
2420 | * - As soon as a "real" console is registered, all bootconsoles | |
2421 | * will be unregistered automatically. | |
2422 | * - Once a "real" console is registered, any attempt to register a | |
2423 | * bootconsoles will be rejected | |
1da177e4 | 2424 | */ |
4d091611 | 2425 | void register_console(struct console *newcon) |
1da177e4 | 2426 | { |
40dc5651 | 2427 | int i; |
1da177e4 | 2428 | unsigned long flags; |
4d091611 | 2429 | struct console *bcon = NULL; |
23475408 | 2430 | struct console_cmdline *c; |
b077bafa | 2431 | static bool has_preferred; |
1da177e4 | 2432 | |
16cf48a6 AB |
2433 | if (console_drivers) |
2434 | for_each_console(bcon) | |
2435 | if (WARN(bcon == newcon, | |
2436 | "console '%s%d' already registered\n", | |
2437 | bcon->name, bcon->index)) | |
2438 | return; | |
2439 | ||
4d091611 RG |
2440 | /* |
2441 | * before we register a new CON_BOOT console, make sure we don't | |
2442 | * already have a valid console | |
2443 | */ | |
2444 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2445 | /* find the last or real console */ | |
2446 | for_each_console(bcon) { | |
2447 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2448 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2449 | newcon->name, newcon->index); |
2450 | return; | |
2451 | } | |
2452 | } | |
69331af7 GH |
2453 | } |
2454 | ||
4d091611 RG |
2455 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2456 | bcon = console_drivers; | |
2457 | ||
b077bafa | 2458 | if (!has_preferred || bcon || !console_drivers) |
ad86ee2b | 2459 | has_preferred = preferred_console >= 0; |
1da177e4 LT |
2460 | |
2461 | /* | |
2462 | * See if we want to use this console driver. If we | |
2463 | * didn't select a console we take the first one | |
2464 | * that registers here. | |
2465 | */ | |
b077bafa | 2466 | if (!has_preferred) { |
4d091611 RG |
2467 | if (newcon->index < 0) |
2468 | newcon->index = 0; | |
2469 | if (newcon->setup == NULL || | |
2470 | newcon->setup(newcon, NULL) == 0) { | |
2471 | newcon->flags |= CON_ENABLED; | |
2472 | if (newcon->device) { | |
2473 | newcon->flags |= CON_CONSDEV; | |
b077bafa | 2474 | has_preferred = true; |
cd3a1b85 | 2475 | } |
1da177e4 LT |
2476 | } |
2477 | } | |
2478 | ||
2479 | /* | |
cf39bf58 AM |
2480 | * See if this console matches one we selected on the command line. |
2481 | * | |
2482 | * There may be several entries in the console_cmdline array matching | |
2483 | * with the same console, one with newcon->match(), another by | |
2484 | * name/index: | |
2485 | * | |
2486 | * pl011,mmio,0x87e024000000,115200 -- added from SPCR | |
2487 | * ttyAMA0 -- added from command line | |
2488 | * | |
2489 | * Traverse the console_cmdline array in reverse order to be | |
2490 | * sure that if this console is preferred then it will be the first | |
2491 | * matching entry. We use the invariant that is maintained in | |
2492 | * __add_preferred_console(). | |
1da177e4 | 2493 | */ |
cf39bf58 AM |
2494 | for (i = console_cmdline_cnt - 1; i >= 0; i--) { |
2495 | c = console_cmdline + i; | |
2496 | ||
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; |
ad86ee2b | 2518 | if (i == preferred_console) { |
4d091611 | 2519 | newcon->flags |= CON_CONSDEV; |
b077bafa | 2520 | has_preferred = true; |
ab4af03a | 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 | */ | |
de6fcbdb | 2561 | logbuf_lock_irqsave(flags); |
7ff9554b KS |
2562 | console_seq = syslog_seq; |
2563 | console_idx = syslog_idx; | |
de6fcbdb | 2564 | logbuf_unlock_irqrestore(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 | |
0c688614 NP |
2644 | /* |
2645 | * Initialize the console device. This is called *early*, so | |
2646 | * we can't necessarily depend on lots of kernel help here. | |
2647 | * Just do some early initializations, and do the complex setup | |
2648 | * later. | |
2649 | */ | |
2650 | void __init console_init(void) | |
2651 | { | |
2652 | initcall_t *call; | |
2653 | ||
2654 | /* Setup the default TTY line discipline. */ | |
2655 | n_tty_init(); | |
2656 | ||
2657 | /* | |
2658 | * set up the console device so that later boot sequences can | |
2659 | * inform about problems etc.. | |
2660 | */ | |
2661 | call = __con_initcall_start; | |
2662 | while (call < __con_initcall_end) { | |
2663 | (*call)(); | |
2664 | call++; | |
2665 | } | |
2666 | } | |
2667 | ||
81cc26f2 TR |
2668 | /* |
2669 | * Some boot consoles access data that is in the init section and which will | |
2670 | * be discarded after the initcalls have been run. To make sure that no code | |
2671 | * will access this data, unregister the boot consoles in a late initcall. | |
2672 | * | |
2673 | * If for some reason, such as deferred probe or the driver being a loadable | |
2674 | * module, the real console hasn't registered yet at this point, there will | |
2675 | * be a brief interval in which no messages are logged to the console, which | |
2676 | * makes it difficult to diagnose problems that occur during this time. | |
2677 | * | |
2678 | * To mitigate this problem somewhat, only unregister consoles whose memory | |
2679 | * intersects with the init section. Note that code exists elsewhere to get | |
2680 | * rid of the boot console as soon as the proper console shows up, so there | |
2681 | * won't be side-effects from postponing the removal. | |
2682 | */ | |
034260d6 | 2683 | static int __init printk_late_init(void) |
0c5564bd | 2684 | { |
4d091611 | 2685 | struct console *con; |
90b14889 | 2686 | int ret; |
4d091611 RG |
2687 | |
2688 | for_each_console(con) { | |
4c30c6f5 | 2689 | if (!keep_bootcon && con->flags & CON_BOOT) { |
81cc26f2 TR |
2690 | /* |
2691 | * Make sure to unregister boot consoles whose data | |
2692 | * resides in the init section before the init section | |
2693 | * is discarded. Boot consoles whose data will stick | |
2694 | * around will automatically be unregistered when the | |
2695 | * proper console replaces them. | |
2696 | */ | |
2697 | if (init_section_intersects(con, sizeof(*con))) | |
2698 | unregister_console(con); | |
cb00e99c | 2699 | } |
0c5564bd | 2700 | } |
90b14889 SAS |
2701 | ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, |
2702 | console_cpu_notify); | |
2703 | WARN_ON(ret < 0); | |
2704 | ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online", | |
2705 | console_cpu_notify, NULL); | |
2706 | WARN_ON(ret < 0); | |
0c5564bd RG |
2707 | return 0; |
2708 | } | |
034260d6 | 2709 | late_initcall(printk_late_init); |
0c5564bd | 2710 | |
7ef3d2fd | 2711 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2712 | /* |
2713 | * Delayed printk version, for scheduler-internal messages: | |
2714 | */ | |
dc72c32e | 2715 | #define PRINTK_PENDING_WAKEUP 0x01 |
458df9fd | 2716 | #define PRINTK_PENDING_OUTPUT 0x02 |
dc72c32e FW |
2717 | |
2718 | static DEFINE_PER_CPU(int, printk_pending); | |
dc72c32e FW |
2719 | |
2720 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2721 | { | |
2722 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2723 | ||
458df9fd SR |
2724 | if (pending & PRINTK_PENDING_OUTPUT) { |
2725 | /* If trylock fails, someone else is doing the printing */ | |
2726 | if (console_trylock()) | |
2727 | console_unlock(); | |
dc72c32e FW |
2728 | } |
2729 | ||
2730 | if (pending & PRINTK_PENDING_WAKEUP) | |
2731 | wake_up_interruptible(&log_wait); | |
2732 | } | |
2733 | ||
2734 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2735 | .func = wake_up_klogd_work_func, | |
2736 | .flags = IRQ_WORK_LAZY, | |
2737 | }; | |
2738 | ||
2739 | void wake_up_klogd(void) | |
2740 | { | |
2741 | preempt_disable(); | |
2742 | if (waitqueue_active(&log_wait)) { | |
2743 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
bb964a92 | 2744 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
dc72c32e FW |
2745 | } |
2746 | preempt_enable(); | |
2747 | } | |
717115e1 | 2748 | |
aac74dc4 | 2749 | int printk_deferred(const char *fmt, ...) |
600e1458 | 2750 | { |
600e1458 | 2751 | va_list args; |
600e1458 PZ |
2752 | int r; |
2753 | ||
81954606 | 2754 | preempt_disable(); |
600e1458 | 2755 | va_start(args, fmt); |
a39d4a85 | 2756 | r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); |
600e1458 PZ |
2757 | va_end(args); |
2758 | ||
458df9fd | 2759 | __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); |
bb964a92 | 2760 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
81954606 | 2761 | preempt_enable(); |
600e1458 PZ |
2762 | |
2763 | return r; | |
2764 | } | |
2765 | ||
1da177e4 LT |
2766 | /* |
2767 | * printk rate limiting, lifted from the networking subsystem. | |
2768 | * | |
641de9d8 UKK |
2769 | * This enforces a rate limit: not more than 10 kernel messages |
2770 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2771 | */ |
641de9d8 UKK |
2772 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2773 | ||
5c828713 | 2774 | int __printk_ratelimit(const char *func) |
1da177e4 | 2775 | { |
5c828713 | 2776 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2777 | } |
5c828713 | 2778 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2779 | |
2780 | /** | |
2781 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2782 | * @caller_jiffies: pointer to caller's state | |
2783 | * @interval_msecs: minimum interval between prints | |
2784 | * | |
2785 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2786 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2787 | * returned true. | |
2788 | */ | |
2789 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2790 | unsigned int interval_msecs) | |
2791 | { | |
249771b8 AE |
2792 | unsigned long elapsed = jiffies - *caller_jiffies; |
2793 | ||
2794 | if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) | |
2795 | return false; | |
2796 | ||
2797 | *caller_jiffies = jiffies; | |
2798 | return true; | |
f46c4833 AM |
2799 | } |
2800 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2801 | |
2802 | static DEFINE_SPINLOCK(dump_list_lock); | |
2803 | static LIST_HEAD(dump_list); | |
2804 | ||
2805 | /** | |
2806 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2807 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2808 | * |
2809 | * Adds a kernel log dumper to the system. The dump callback in the | |
2810 | * structure will be called when the kernel oopses or panics and must be | |
2811 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2812 | */ | |
2813 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2814 | { | |
2815 | unsigned long flags; | |
2816 | int err = -EBUSY; | |
2817 | ||
2818 | /* The dump callback needs to be set */ | |
2819 | if (!dumper->dump) | |
2820 | return -EINVAL; | |
2821 | ||
2822 | spin_lock_irqsave(&dump_list_lock, flags); | |
2823 | /* Don't allow registering multiple times */ | |
2824 | if (!dumper->registered) { | |
2825 | dumper->registered = 1; | |
fb842b00 | 2826 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2827 | err = 0; |
2828 | } | |
2829 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2830 | ||
2831 | return err; | |
2832 | } | |
2833 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2834 | ||
2835 | /** | |
2836 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2837 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2838 | * |
2839 | * Removes a dump device from the system. Returns zero on success and | |
2840 | * %-EINVAL otherwise. | |
2841 | */ | |
2842 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2843 | { | |
2844 | unsigned long flags; | |
2845 | int err = -EINVAL; | |
2846 | ||
2847 | spin_lock_irqsave(&dump_list_lock, flags); | |
2848 | if (dumper->registered) { | |
2849 | dumper->registered = 0; | |
fb842b00 | 2850 | list_del_rcu(&dumper->list); |
456b565c SK |
2851 | err = 0; |
2852 | } | |
2853 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2854 | synchronize_rcu(); |
456b565c SK |
2855 | |
2856 | return err; | |
2857 | } | |
2858 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2859 | ||
7ff9554b KS |
2860 | static bool always_kmsg_dump; |
2861 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2862 | ||
456b565c SK |
2863 | /** |
2864 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2865 | * @reason: the reason (oops, panic etc) for dumping | |
2866 | * | |
e2ae715d KS |
2867 | * Call each of the registered dumper's dump() callback, which can |
2868 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2869 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2870 | */ |
2871 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2872 | { | |
456b565c | 2873 | struct kmsg_dumper *dumper; |
456b565c SK |
2874 | unsigned long flags; |
2875 | ||
c22ab332 MG |
2876 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2877 | return; | |
2878 | ||
e2ae715d KS |
2879 | rcu_read_lock(); |
2880 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2881 | if (dumper->max_reason && reason > dumper->max_reason) | |
2882 | continue; | |
2883 | ||
2884 | /* initialize iterator with data about the stored records */ | |
2885 | dumper->active = true; | |
2886 | ||
de6fcbdb | 2887 | logbuf_lock_irqsave(flags); |
e2ae715d KS |
2888 | dumper->cur_seq = clear_seq; |
2889 | dumper->cur_idx = clear_idx; | |
2890 | dumper->next_seq = log_next_seq; | |
2891 | dumper->next_idx = log_next_idx; | |
de6fcbdb | 2892 | logbuf_unlock_irqrestore(flags); |
e2ae715d KS |
2893 | |
2894 | /* invoke dumper which will iterate over records */ | |
2895 | dumper->dump(dumper, reason); | |
2896 | ||
2897 | /* reset iterator */ | |
2898 | dumper->active = false; | |
2899 | } | |
2900 | rcu_read_unlock(); | |
2901 | } | |
2902 | ||
2903 | /** | |
533827c9 | 2904 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2905 | * @dumper: registered kmsg dumper |
2906 | * @syslog: include the "<4>" prefixes | |
2907 | * @line: buffer to copy the line to | |
2908 | * @size: maximum size of the buffer | |
2909 | * @len: length of line placed into buffer | |
2910 | * | |
2911 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2912 | * record, and copy one record into the provided buffer. | |
2913 | * | |
2914 | * Consecutive calls will return the next available record moving | |
2915 | * towards the end of the buffer with the youngest messages. | |
2916 | * | |
2917 | * A return value of FALSE indicates that there are no more records to | |
2918 | * read. | |
533827c9 AV |
2919 | * |
2920 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2921 | */ |
533827c9 AV |
2922 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2923 | char *line, size_t size, size_t *len) | |
e2ae715d | 2924 | { |
62e32ac3 | 2925 | struct printk_log *msg; |
e2ae715d KS |
2926 | size_t l = 0; |
2927 | bool ret = false; | |
2928 | ||
2929 | if (!dumper->active) | |
2930 | goto out; | |
7ff9554b | 2931 | |
e2ae715d KS |
2932 | if (dumper->cur_seq < log_first_seq) { |
2933 | /* messages are gone, move to first available one */ | |
2934 | dumper->cur_seq = log_first_seq; | |
2935 | dumper->cur_idx = log_first_idx; | |
2936 | } | |
456b565c | 2937 | |
e2ae715d | 2938 | /* last entry */ |
533827c9 | 2939 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2940 | goto out; |
456b565c | 2941 | |
e2ae715d | 2942 | msg = log_from_idx(dumper->cur_idx); |
5aa068ea | 2943 | l = msg_print_text(msg, syslog, line, size); |
e2ae715d KS |
2944 | |
2945 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2946 | dumper->cur_seq++; | |
2947 | ret = true; | |
e2ae715d KS |
2948 | out: |
2949 | if (len) | |
2950 | *len = l; | |
2951 | return ret; | |
2952 | } | |
533827c9 AV |
2953 | |
2954 | /** | |
2955 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2956 | * @dumper: registered kmsg dumper | |
2957 | * @syslog: include the "<4>" prefixes | |
2958 | * @line: buffer to copy the line to | |
2959 | * @size: maximum size of the buffer | |
2960 | * @len: length of line placed into buffer | |
2961 | * | |
2962 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2963 | * record, and copy one record into the provided buffer. | |
2964 | * | |
2965 | * Consecutive calls will return the next available record moving | |
2966 | * towards the end of the buffer with the youngest messages. | |
2967 | * | |
2968 | * A return value of FALSE indicates that there are no more records to | |
2969 | * read. | |
2970 | */ | |
2971 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2972 | char *line, size_t size, size_t *len) | |
2973 | { | |
2974 | unsigned long flags; | |
2975 | bool ret; | |
2976 | ||
de6fcbdb | 2977 | logbuf_lock_irqsave(flags); |
533827c9 | 2978 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); |
de6fcbdb | 2979 | logbuf_unlock_irqrestore(flags); |
533827c9 AV |
2980 | |
2981 | return ret; | |
2982 | } | |
e2ae715d KS |
2983 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2984 | ||
2985 | /** | |
2986 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2987 | * @dumper: registered kmsg dumper | |
2988 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2989 | * @buf: buffer to copy the line to |
e2ae715d KS |
2990 | * @size: maximum size of the buffer |
2991 | * @len: length of line placed into buffer | |
2992 | * | |
2993 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2994 | * with as many of the the *youngest* kmsg records that fit into it. | |
2995 | * If the buffer is large enough, all available kmsg records will be | |
2996 | * copied with a single call. | |
2997 | * | |
2998 | * Consecutive calls will fill the buffer with the next block of | |
2999 | * available older records, not including the earlier retrieved ones. | |
3000 | * | |
3001 | * A return value of FALSE indicates that there are no more records to | |
3002 | * read. | |
3003 | */ | |
3004 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
3005 | char *buf, size_t size, size_t *len) | |
3006 | { | |
3007 | unsigned long flags; | |
3008 | u64 seq; | |
3009 | u32 idx; | |
3010 | u64 next_seq; | |
3011 | u32 next_idx; | |
3012 | size_t l = 0; | |
3013 | bool ret = false; | |
3014 | ||
3015 | if (!dumper->active) | |
3016 | goto out; | |
3017 | ||
de6fcbdb | 3018 | logbuf_lock_irqsave(flags); |
e2ae715d KS |
3019 | if (dumper->cur_seq < log_first_seq) { |
3020 | /* messages are gone, move to first available one */ | |
3021 | dumper->cur_seq = log_first_seq; | |
3022 | dumper->cur_idx = log_first_idx; | |
3023 | } | |
3024 | ||
3025 | /* last entry */ | |
3026 | if (dumper->cur_seq >= dumper->next_seq) { | |
de6fcbdb | 3027 | logbuf_unlock_irqrestore(flags); |
e2ae715d KS |
3028 | goto out; |
3029 | } | |
3030 | ||
3031 | /* calculate length of entire buffer */ | |
3032 | seq = dumper->cur_seq; | |
3033 | idx = dumper->cur_idx; | |
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, true, NULL, 0); |
e2ae715d KS |
3038 | idx = log_next(idx); |
3039 | seq++; | |
3040 | } | |
3041 | ||
3042 | /* move first record forward until length fits into the buffer */ | |
3043 | seq = dumper->cur_seq; | |
3044 | idx = dumper->cur_idx; | |
3045 | while (l > size && seq < dumper->next_seq) { | |
62e32ac3 | 3046 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 3047 | |
5aa068ea | 3048 | l -= msg_print_text(msg, true, NULL, 0); |
e2ae715d KS |
3049 | idx = log_next(idx); |
3050 | seq++; | |
456b565c | 3051 | } |
e2ae715d KS |
3052 | |
3053 | /* last message in next interation */ | |
3054 | next_seq = seq; | |
3055 | next_idx = idx; | |
3056 | ||
3057 | l = 0; | |
3058 | while (seq < dumper->next_seq) { | |
62e32ac3 | 3059 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3060 | |
5aa068ea | 3061 | l += msg_print_text(msg, syslog, buf + l, size - l); |
e2ae715d KS |
3062 | idx = log_next(idx); |
3063 | seq++; | |
3064 | } | |
3065 | ||
3066 | dumper->next_seq = next_seq; | |
3067 | dumper->next_idx = next_idx; | |
3068 | ret = true; | |
de6fcbdb | 3069 | logbuf_unlock_irqrestore(flags); |
e2ae715d KS |
3070 | out: |
3071 | if (len) | |
3072 | *len = l; | |
3073 | return ret; | |
3074 | } | |
3075 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 3076 | |
533827c9 AV |
3077 | /** |
3078 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
3079 | * @dumper: registered kmsg dumper | |
3080 | * | |
3081 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3082 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3083 | * times within the same dumper.dump() callback. | |
3084 | * | |
3085 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
3086 | */ | |
3087 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
3088 | { | |
3089 | dumper->cur_seq = clear_seq; | |
3090 | dumper->cur_idx = clear_idx; | |
3091 | dumper->next_seq = log_next_seq; | |
3092 | dumper->next_idx = log_next_idx; | |
3093 | } | |
3094 | ||
e2ae715d KS |
3095 | /** |
3096 | * kmsg_dump_rewind - reset the interator | |
3097 | * @dumper: registered kmsg dumper | |
3098 | * | |
3099 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3100 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3101 | * times within the same dumper.dump() callback. | |
3102 | */ | |
3103 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
3104 | { | |
3105 | unsigned long flags; | |
3106 | ||
de6fcbdb | 3107 | logbuf_lock_irqsave(flags); |
533827c9 | 3108 | kmsg_dump_rewind_nolock(dumper); |
de6fcbdb | 3109 | logbuf_unlock_irqrestore(flags); |
456b565c | 3110 | } |
e2ae715d | 3111 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 3112 | |
98e5e1bf TH |
3113 | static char dump_stack_arch_desc_str[128]; |
3114 | ||
3115 | /** | |
3116 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
3117 | * @fmt: printf-style format string | |
3118 | * @...: arguments for the format string | |
3119 | * | |
3120 | * The configured string will be printed right after utsname during task | |
3121 | * dumps. Usually used to add arch-specific system identifiers. If an | |
3122 | * arch wants to make use of such an ID string, it should initialize this | |
3123 | * as soon as possible during boot. | |
3124 | */ | |
3125 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
3126 | { | |
3127 | va_list args; | |
3128 | ||
3129 | va_start(args, fmt); | |
3130 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
3131 | fmt, args); | |
3132 | va_end(args); | |
3133 | } | |
3134 | ||
196779b9 TH |
3135 | /** |
3136 | * dump_stack_print_info - print generic debug info for dump_stack() | |
3137 | * @log_lvl: log level | |
3138 | * | |
3139 | * Arch-specific dump_stack() implementations can use this function to | |
3140 | * print out the same debug information as the generic dump_stack(). | |
3141 | */ | |
3142 | void dump_stack_print_info(const char *log_lvl) | |
3143 | { | |
3144 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
3145 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
3146 | print_tainted(), init_utsname()->release, | |
3147 | (int)strcspn(init_utsname()->version, " "), | |
3148 | init_utsname()->version); | |
98e5e1bf TH |
3149 | |
3150 | if (dump_stack_arch_desc_str[0] != '\0') | |
3151 | printk("%sHardware name: %s\n", | |
3152 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
3153 | |
3154 | print_worker_info(log_lvl, current); | |
196779b9 TH |
3155 | } |
3156 | ||
a43cb95d TH |
3157 | /** |
3158 | * show_regs_print_info - print generic debug info for show_regs() | |
3159 | * @log_lvl: log level | |
3160 | * | |
3161 | * show_regs() implementations can use this function to print out generic | |
3162 | * debug information. | |
3163 | */ | |
3164 | void show_regs_print_info(const char *log_lvl) | |
3165 | { | |
3166 | dump_stack_print_info(log_lvl); | |
3167 | ||
8b70ca65 AL |
3168 | printk("%stask: %p task.stack: %p\n", |
3169 | log_lvl, current, task_stack_page(current)); | |
a43cb95d TH |
3170 | } |
3171 | ||
7ef3d2fd | 3172 | #endif |