Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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. |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
Christian Kujau | 624dffc | 2006-01-15 02:43:54 +0100 | [diff] [blame] | 14 | * manfred@colorfullife.com |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | * Rewrote bits to get rid of console_lock |
Francois Cami | e1f8e87 | 2008-10-15 22:01:59 -0700 | [diff] [blame] | 16 | * 01Mar01 Andrew Morton |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | */ |
| 18 | |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/tty.h> |
| 22 | #include <linux/tty_driver.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/console.h> |
| 24 | #include <linux/init.h> |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 25 | #include <linux/jiffies.h> |
| 26 | #include <linux/nmi.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/module.h> |
Jan Engelhardt | 3b9c041 | 2006-06-25 05:48:15 -0700 | [diff] [blame] | 28 | #include <linux/moduleparam.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/delay.h> |
| 31 | #include <linux/smp.h> |
| 32 | #include <linux/security.h> |
| 33 | #include <linux/bootmem.h> |
| 34 | #include <linux/syscalls.h> |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 35 | #include <linux/kexec.h> |
Ingo Molnar | 3fff4c4 | 2009-09-22 16:18:09 +0200 | [diff] [blame] | 36 | #include <linux/ratelimit.h> |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 37 | #include <linux/kmsg_dump.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | |
| 39 | #include <asm/uaccess.h> |
| 40 | |
Ingo Molnar | 076f977 | 2008-01-30 13:33:06 +0100 | [diff] [blame] | 41 | /* |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 42 | * for_each_console() allows you to iterate on each console |
| 43 | */ |
| 44 | #define for_each_console(con) \ |
| 45 | for (con = console_drivers; con != NULL; con = con->next) |
| 46 | |
| 47 | /* |
Ingo Molnar | 076f977 | 2008-01-30 13:33:06 +0100 | [diff] [blame] | 48 | * Architectures can override it: |
| 49 | */ |
Jiri Slaby | e17ba73 | 2008-05-12 15:44:40 +0200 | [diff] [blame] | 50 | void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) |
Ingo Molnar | 076f977 | 2008-01-30 13:33:06 +0100 | [diff] [blame] | 51 | { |
| 52 | } |
| 53 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
| 55 | |
| 56 | /* printk's without a loglevel use this.. */ |
| 57 | #define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */ |
| 58 | |
| 59 | /* We show everything that is MORE important than this.. */ |
| 60 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ |
| 61 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ |
| 62 | |
| 63 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
| 64 | |
| 65 | int console_printk[4] = { |
| 66 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ |
| 67 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ |
| 68 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ |
| 69 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ |
| 70 | }; |
| 71 | |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 72 | static int saved_console_loglevel = -1; |
| 73 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | /* |
Patrick Pletscher | 0bbfb7c | 2007-02-17 20:10:16 +0100 | [diff] [blame] | 75 | * Low level drivers may need that to know if they can schedule in |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | * their unblank() callback or not. So let's export it. |
| 77 | */ |
| 78 | int oops_in_progress; |
| 79 | EXPORT_SYMBOL(oops_in_progress); |
| 80 | |
| 81 | /* |
| 82 | * console_sem protects the console_drivers list, and also |
| 83 | * provides serialisation for access to the entire console |
| 84 | * driver system. |
| 85 | */ |
| 86 | static DECLARE_MUTEX(console_sem); |
| 87 | struct console *console_drivers; |
Ingo Molnar | a29d1cf | 2008-06-02 13:19:08 +0200 | [diff] [blame] | 88 | EXPORT_SYMBOL_GPL(console_drivers); |
| 89 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | /* |
| 91 | * This is used for debugging the mess that is the VT code by |
| 92 | * keeping track if we have the console semaphore held. It's |
| 93 | * definitely not the perfect debug tool (we don't know if _WE_ |
| 94 | * hold it are racing, but it helps tracking those weird code |
| 95 | * path in the console code where we end up in places I want |
| 96 | * locked without the console sempahore held |
| 97 | */ |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 98 | static int console_locked, console_suspended; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
| 100 | /* |
| 101 | * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars |
| 102 | * It is also used in interesting ways to provide interlocking in |
| 103 | * release_console_sem(). |
| 104 | */ |
| 105 | static DEFINE_SPINLOCK(logbuf_lock); |
| 106 | |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 107 | #define LOG_BUF_MASK (log_buf_len-1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) |
| 109 | |
| 110 | /* |
| 111 | * The indices into log_buf are not constrained to log_buf_len - they |
| 112 | * must be masked before subscripting |
| 113 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 114 | static unsigned log_start; /* Index into log_buf: next char to be read by syslog() */ |
| 115 | static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */ |
| 116 | static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | |
| 118 | /* |
| 119 | * Array of consoles built from command line options (console=) |
| 120 | */ |
| 121 | struct console_cmdline |
| 122 | { |
| 123 | char name[8]; /* Name of the driver */ |
| 124 | int index; /* Minor dev. to use */ |
| 125 | char *options; /* Options for the driver */ |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 126 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 127 | char *brl_options; /* Options for braille driver */ |
| 128 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | }; |
| 130 | |
| 131 | #define MAX_CMDLINECONSOLES 8 |
| 132 | |
| 133 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; |
| 134 | static int selected_console = -1; |
| 135 | static int preferred_console = -1; |
Markus Armbruster | 9e124fe | 2008-05-26 23:31:07 +0100 | [diff] [blame] | 136 | int console_set_on_cmdline; |
| 137 | EXPORT_SYMBOL(console_set_on_cmdline); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | |
| 139 | /* Flag: console code may call schedule() */ |
| 140 | static int console_may_schedule; |
| 141 | |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 142 | #ifdef CONFIG_PRINTK |
| 143 | |
| 144 | static char __log_buf[__LOG_BUF_LEN]; |
| 145 | static char *log_buf = __log_buf; |
| 146 | static int log_buf_len = __LOG_BUF_LEN; |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 147 | static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 148 | |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 149 | #ifdef CONFIG_KEXEC |
| 150 | /* |
| 151 | * This appends the listed symbols to /proc/vmcoreinfo |
| 152 | * |
| 153 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to |
| 154 | * obtain access to symbols that are otherwise very difficult to locate. These |
| 155 | * symbols are specifically used so that utilities can access and extract the |
| 156 | * dmesg log from a vmcore file after a crash. |
| 157 | */ |
| 158 | void log_buf_kexec_setup(void) |
| 159 | { |
| 160 | VMCOREINFO_SYMBOL(log_buf); |
| 161 | VMCOREINFO_SYMBOL(log_end); |
| 162 | VMCOREINFO_SYMBOL(log_buf_len); |
| 163 | VMCOREINFO_SYMBOL(logged_chars); |
| 164 | } |
| 165 | #endif |
| 166 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | static int __init log_buf_len_setup(char *str) |
| 168 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 169 | unsigned size = memparse(str, &str); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | unsigned long flags; |
| 171 | |
| 172 | if (size) |
| 173 | size = roundup_pow_of_two(size); |
| 174 | if (size > log_buf_len) { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 175 | unsigned start, dest_idx, offset; |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 176 | char *new_log_buf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
| 178 | new_log_buf = alloc_bootmem(size); |
| 179 | if (!new_log_buf) { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 180 | printk(KERN_WARNING "log_buf_len: allocation failed\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | goto out; |
| 182 | } |
| 183 | |
| 184 | spin_lock_irqsave(&logbuf_lock, flags); |
| 185 | log_buf_len = size; |
| 186 | log_buf = new_log_buf; |
| 187 | |
| 188 | offset = start = min(con_start, log_start); |
| 189 | dest_idx = 0; |
| 190 | while (start != log_end) { |
| 191 | log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)]; |
| 192 | start++; |
| 193 | dest_idx++; |
| 194 | } |
| 195 | log_start -= offset; |
| 196 | con_start -= offset; |
| 197 | log_end -= offset; |
| 198 | spin_unlock_irqrestore(&logbuf_lock, flags); |
| 199 | |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 200 | printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | } |
| 202 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | return 1; |
| 204 | } |
| 205 | |
| 206 | __setup("log_buf_len=", log_buf_len_setup); |
| 207 | |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 208 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
| 209 | |
| 210 | static unsigned int boot_delay; /* msecs delay after each printk during bootup */ |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 211 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 212 | |
| 213 | static int __init boot_delay_setup(char *str) |
| 214 | { |
| 215 | unsigned long lpj; |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 216 | |
| 217 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ |
| 218 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; |
| 219 | |
| 220 | get_option(&str, &boot_delay); |
| 221 | if (boot_delay > 10 * 1000) |
| 222 | boot_delay = 0; |
| 223 | |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 224 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
| 225 | "HZ: %d, loops_per_msec: %llu\n", |
| 226 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 227 | return 1; |
| 228 | } |
| 229 | __setup("boot_delay=", boot_delay_setup); |
| 230 | |
| 231 | static void boot_delay_msec(void) |
| 232 | { |
| 233 | unsigned long long k; |
| 234 | unsigned long timeout; |
| 235 | |
| 236 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) |
| 237 | return; |
| 238 | |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 239 | k = (unsigned long long)loops_per_msec * boot_delay; |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 240 | |
| 241 | timeout = jiffies + msecs_to_jiffies(boot_delay); |
| 242 | while (k) { |
| 243 | k--; |
| 244 | cpu_relax(); |
| 245 | /* |
| 246 | * use (volatile) jiffies to prevent |
| 247 | * compiler reduction; loop termination via jiffies |
| 248 | * is secondary and may or may not happen. |
| 249 | */ |
| 250 | if (time_after(jiffies, timeout)) |
| 251 | break; |
| 252 | touch_nmi_watchdog(); |
| 253 | } |
| 254 | } |
| 255 | #else |
| 256 | static inline void boot_delay_msec(void) |
| 257 | { |
| 258 | } |
| 259 | #endif |
| 260 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | /* |
| 262 | * Commands to do_syslog: |
| 263 | * |
| 264 | * 0 -- Close the log. Currently a NOP. |
| 265 | * 1 -- Open the log. Currently a NOP. |
| 266 | * 2 -- Read from the log. |
| 267 | * 3 -- Read all messages remaining in the ring buffer. |
| 268 | * 4 -- Read and clear all messages remaining in the ring buffer |
| 269 | * 5 -- Clear ring buffer. |
| 270 | * 6 -- Disable printk's to console |
| 271 | * 7 -- Enable printk's to console |
| 272 | * 8 -- Set level of messages printed to console |
| 273 | * 9 -- Return number of unread characters in the log buffer |
| 274 | * 10 -- Return size of the log buffer |
| 275 | */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 276 | int do_syslog(int type, char __user *buf, int len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 278 | unsigned i, j, limit, count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | int do_clear = 0; |
| 280 | char c; |
| 281 | int error = 0; |
| 282 | |
| 283 | error = security_syslog(type); |
| 284 | if (error) |
| 285 | return error; |
| 286 | |
| 287 | switch (type) { |
| 288 | case 0: /* Close log */ |
| 289 | break; |
| 290 | case 1: /* Open log */ |
| 291 | break; |
| 292 | case 2: /* Read from log */ |
| 293 | error = -EINVAL; |
| 294 | if (!buf || len < 0) |
| 295 | goto out; |
| 296 | error = 0; |
| 297 | if (!len) |
| 298 | goto out; |
| 299 | if (!access_ok(VERIFY_WRITE, buf, len)) { |
| 300 | error = -EFAULT; |
| 301 | goto out; |
| 302 | } |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 303 | error = wait_event_interruptible(log_wait, |
| 304 | (log_start - log_end)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | if (error) |
| 306 | goto out; |
| 307 | i = 0; |
| 308 | spin_lock_irq(&logbuf_lock); |
| 309 | while (!error && (log_start != log_end) && i < len) { |
| 310 | c = LOG_BUF(log_start); |
| 311 | log_start++; |
| 312 | spin_unlock_irq(&logbuf_lock); |
| 313 | error = __put_user(c,buf); |
| 314 | buf++; |
| 315 | i++; |
| 316 | cond_resched(); |
| 317 | spin_lock_irq(&logbuf_lock); |
| 318 | } |
| 319 | spin_unlock_irq(&logbuf_lock); |
| 320 | if (!error) |
| 321 | error = i; |
| 322 | break; |
| 323 | case 4: /* Read/clear last kernel messages */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 324 | do_clear = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | /* FALL THRU */ |
| 326 | case 3: /* Read last kernel messages */ |
| 327 | error = -EINVAL; |
| 328 | if (!buf || len < 0) |
| 329 | goto out; |
| 330 | error = 0; |
| 331 | if (!len) |
| 332 | goto out; |
| 333 | if (!access_ok(VERIFY_WRITE, buf, len)) { |
| 334 | error = -EFAULT; |
| 335 | goto out; |
| 336 | } |
| 337 | count = len; |
| 338 | if (count > log_buf_len) |
| 339 | count = log_buf_len; |
| 340 | spin_lock_irq(&logbuf_lock); |
| 341 | if (count > logged_chars) |
| 342 | count = logged_chars; |
| 343 | if (do_clear) |
| 344 | logged_chars = 0; |
| 345 | limit = log_end; |
| 346 | /* |
| 347 | * __put_user() could sleep, and while we sleep |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 348 | * printk() could overwrite the messages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | * we try to copy to user space. Therefore |
| 350 | * the messages are copied in reverse. <manfreds> |
| 351 | */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 352 | for (i = 0; i < count && !error; i++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | j = limit-1-i; |
| 354 | if (j + log_buf_len < log_end) |
| 355 | break; |
| 356 | c = LOG_BUF(j); |
| 357 | spin_unlock_irq(&logbuf_lock); |
| 358 | error = __put_user(c,&buf[count-1-i]); |
| 359 | cond_resched(); |
| 360 | spin_lock_irq(&logbuf_lock); |
| 361 | } |
| 362 | spin_unlock_irq(&logbuf_lock); |
| 363 | if (error) |
| 364 | break; |
| 365 | error = i; |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 366 | if (i != count) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | int offset = count-error; |
| 368 | /* buffer overflow during copy, correct user buffer. */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 369 | for (i = 0; i < error; i++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | if (__get_user(c,&buf[i+offset]) || |
| 371 | __put_user(c,&buf[i])) { |
| 372 | error = -EFAULT; |
| 373 | break; |
| 374 | } |
| 375 | cond_resched(); |
| 376 | } |
| 377 | } |
| 378 | break; |
| 379 | case 5: /* Clear ring buffer */ |
| 380 | logged_chars = 0; |
| 381 | break; |
| 382 | case 6: /* Disable logging to console */ |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 383 | if (saved_console_loglevel == -1) |
| 384 | saved_console_loglevel = console_loglevel; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | console_loglevel = minimum_console_loglevel; |
| 386 | break; |
| 387 | case 7: /* Enable logging to console */ |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 388 | if (saved_console_loglevel != -1) { |
| 389 | console_loglevel = saved_console_loglevel; |
| 390 | saved_console_loglevel = -1; |
| 391 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | break; |
| 393 | case 8: /* Set level of messages printed to console */ |
| 394 | error = -EINVAL; |
| 395 | if (len < 1 || len > 8) |
| 396 | goto out; |
| 397 | if (len < minimum_console_loglevel) |
| 398 | len = minimum_console_loglevel; |
| 399 | console_loglevel = len; |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 400 | /* Implicitly re-enable logging to console */ |
| 401 | saved_console_loglevel = -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | error = 0; |
| 403 | break; |
| 404 | case 9: /* Number of chars in the log buffer */ |
| 405 | error = log_end - log_start; |
| 406 | break; |
| 407 | case 10: /* Size of the log buffer */ |
| 408 | error = log_buf_len; |
| 409 | break; |
| 410 | default: |
| 411 | error = -EINVAL; |
| 412 | break; |
| 413 | } |
| 414 | out: |
| 415 | return error; |
| 416 | } |
| 417 | |
Heiko Carstens | 1e7bfb2 | 2009-01-14 14:14:29 +0100 | [diff] [blame] | 418 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | { |
| 420 | return do_syslog(type, buf, len); |
| 421 | } |
| 422 | |
| 423 | /* |
| 424 | * Call the console drivers on a range of log_buf |
| 425 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 426 | static void __call_console_drivers(unsigned start, unsigned end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | { |
| 428 | struct console *con; |
| 429 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 430 | for_each_console(con) { |
Michael Ellerman | 76a8ad29 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 431 | if ((con->flags & CON_ENABLED) && con->write && |
| 432 | (cpu_online(smp_processor_id()) || |
| 433 | (con->flags & CON_ANYTIME))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | con->write(con, &LOG_BUF(start), end - start); |
| 435 | } |
| 436 | } |
| 437 | |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 438 | static int __read_mostly ignore_loglevel; |
| 439 | |
Adrian Bunk | 99eea6a | 2006-12-22 01:07:00 -0800 | [diff] [blame] | 440 | static int __init ignore_loglevel_setup(char *str) |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 441 | { |
| 442 | ignore_loglevel = 1; |
| 443 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); |
| 444 | |
Ingo Molnar | c4772d9 | 2008-01-31 22:45:23 +0100 | [diff] [blame] | 445 | return 0; |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 446 | } |
| 447 | |
Ingo Molnar | c4772d9 | 2008-01-31 22:45:23 +0100 | [diff] [blame] | 448 | early_param("ignore_loglevel", ignore_loglevel_setup); |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 449 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | /* |
| 451 | * Write out chars from start to end - 1 inclusive |
| 452 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 453 | static void _call_console_drivers(unsigned start, |
| 454 | unsigned end, int msg_log_level) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | { |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 456 | if ((msg_log_level < console_loglevel || ignore_loglevel) && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | console_drivers && start != end) { |
| 458 | if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) { |
| 459 | /* wrapped write */ |
| 460 | __call_console_drivers(start & LOG_BUF_MASK, |
| 461 | log_buf_len); |
| 462 | __call_console_drivers(0, end & LOG_BUF_MASK); |
| 463 | } else { |
| 464 | __call_console_drivers(start, end); |
| 465 | } |
| 466 | } |
| 467 | } |
| 468 | |
| 469 | /* |
| 470 | * Call the console drivers, asking them to write out |
| 471 | * log_buf[start] to log_buf[end - 1]. |
| 472 | * The console_sem must be held. |
| 473 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 474 | static void call_console_drivers(unsigned start, unsigned end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 476 | unsigned cur_index, start_print; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | static int msg_level = -1; |
| 478 | |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 479 | BUG_ON(((int)(start - end)) > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | |
| 481 | cur_index = start; |
| 482 | start_print = start; |
| 483 | while (cur_index != end) { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 484 | if (msg_level < 0 && ((end - cur_index) > 2) && |
| 485 | LOG_BUF(cur_index + 0) == '<' && |
| 486 | LOG_BUF(cur_index + 1) >= '0' && |
| 487 | LOG_BUF(cur_index + 1) <= '7' && |
| 488 | LOG_BUF(cur_index + 2) == '>') { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | msg_level = LOG_BUF(cur_index + 1) - '0'; |
| 490 | cur_index += 3; |
| 491 | start_print = cur_index; |
| 492 | } |
| 493 | while (cur_index != end) { |
| 494 | char c = LOG_BUF(cur_index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 496 | cur_index++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | if (c == '\n') { |
| 498 | if (msg_level < 0) { |
| 499 | /* |
| 500 | * printk() has already given us loglevel tags in |
| 501 | * the buffer. This code is here in case the |
| 502 | * log buffer has wrapped right round and scribbled |
| 503 | * on those tags |
| 504 | */ |
| 505 | msg_level = default_message_loglevel; |
| 506 | } |
| 507 | _call_console_drivers(start_print, cur_index, msg_level); |
| 508 | msg_level = -1; |
| 509 | start_print = cur_index; |
| 510 | break; |
| 511 | } |
| 512 | } |
| 513 | } |
| 514 | _call_console_drivers(start_print, end, msg_level); |
| 515 | } |
| 516 | |
| 517 | static void emit_log_char(char c) |
| 518 | { |
| 519 | LOG_BUF(log_end) = c; |
| 520 | log_end++; |
| 521 | if (log_end - log_start > log_buf_len) |
| 522 | log_start = log_end - log_buf_len; |
| 523 | if (log_end - con_start > log_buf_len) |
| 524 | con_start = log_end - log_buf_len; |
| 525 | if (logged_chars < log_buf_len) |
| 526 | logged_chars++; |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * Zap console related locks when oopsing. Only zap at most once |
| 531 | * every 10 seconds, to leave time for slow consoles to print a |
| 532 | * full oops. |
| 533 | */ |
| 534 | static void zap_locks(void) |
| 535 | { |
| 536 | static unsigned long oops_timestamp; |
| 537 | |
| 538 | if (time_after_eq(jiffies, oops_timestamp) && |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 539 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | return; |
| 541 | |
| 542 | oops_timestamp = jiffies; |
| 543 | |
| 544 | /* If a crash is occurring, make sure we can't deadlock */ |
| 545 | spin_lock_init(&logbuf_lock); |
| 546 | /* And make sure that we print immediately */ |
| 547 | init_MUTEX(&console_sem); |
| 548 | } |
| 549 | |
| 550 | #if defined(CONFIG_PRINTK_TIME) |
| 551 | static int printk_time = 1; |
| 552 | #else |
| 553 | static int printk_time = 0; |
| 554 | #endif |
Randy Dunlap | e84845c | 2007-07-15 23:40:25 -0700 | [diff] [blame] | 555 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | |
Michael Ellerman | 76a8ad29 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 557 | /* Check if we have any console registered that can be called early in boot. */ |
| 558 | static int have_callable_console(void) |
| 559 | { |
| 560 | struct console *con; |
| 561 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 562 | for_each_console(con) |
Michael Ellerman | 76a8ad29 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 563 | if (con->flags & CON_ANYTIME) |
| 564 | return 1; |
| 565 | |
| 566 | return 0; |
| 567 | } |
| 568 | |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 569 | /** |
| 570 | * printk - print a kernel message |
| 571 | * @fmt: format string |
| 572 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 573 | * This is printk(). It can be called from any context. We want it to work. |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 574 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | * We try to grab the console_sem. If we succeed, it's easy - we log the output and |
| 576 | * call the console drivers. If we fail to get the semaphore we place the output |
| 577 | * into the log buffer and return. The current holder of the console_sem will |
| 578 | * notice the new output in release_console_sem() and will send it to the |
| 579 | * consoles before releasing the semaphore. |
| 580 | * |
| 581 | * One effect of this deferred printing is that code which calls printk() and |
| 582 | * then changes console_loglevel may break. This is because console_loglevel |
| 583 | * is inspected when the actual printing occurs. |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 584 | * |
| 585 | * See also: |
| 586 | * printf(3) |
Andi Kleen | 20036fd | 2008-10-15 22:02:02 -0700 | [diff] [blame] | 587 | * |
| 588 | * See the vsnprintf() documentation for format string extensions over C99. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | */ |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 590 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | asmlinkage int printk(const char *fmt, ...) |
| 592 | { |
| 593 | va_list args; |
| 594 | int r; |
| 595 | |
| 596 | va_start(args, fmt); |
| 597 | r = vprintk(fmt, args); |
| 598 | va_end(args); |
| 599 | |
| 600 | return r; |
| 601 | } |
| 602 | |
David Howells | fe21773 | 2005-09-06 15:16:34 -0700 | [diff] [blame] | 603 | /* cpu currently holding logbuf_lock */ |
| 604 | static volatile unsigned int printk_cpu = UINT_MAX; |
| 605 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 606 | /* |
| 607 | * Can we actually use the console at this time on this cpu? |
| 608 | * |
| 609 | * Console drivers may assume that per-cpu resources have |
| 610 | * been allocated. So unless they're explicitly marked as |
| 611 | * being able to cope (CON_ANYTIME) don't call them until |
| 612 | * this CPU is officially up. |
| 613 | */ |
| 614 | static inline int can_use_console(unsigned int cpu) |
| 615 | { |
| 616 | return cpu_online(cpu) || have_callable_console(); |
| 617 | } |
| 618 | |
| 619 | /* |
| 620 | * Try to get console ownership to actually show the kernel |
| 621 | * messages from a 'printk'. Return true (and with the |
| 622 | * console_semaphore held, and 'console_locked' set) if it |
| 623 | * is successful, false otherwise. |
| 624 | * |
| 625 | * This gets called with the 'logbuf_lock' spinlock held and |
| 626 | * interrupts disabled. It should return with 'lockbuf_lock' |
| 627 | * released but interrupts still disabled. |
| 628 | */ |
| 629 | static int acquire_console_semaphore_for_printk(unsigned int cpu) |
| 630 | { |
| 631 | int retval = 0; |
| 632 | |
Linus Torvalds | 093a07e | 2008-04-15 13:09:54 -0700 | [diff] [blame] | 633 | if (!try_acquire_console_sem()) { |
| 634 | retval = 1; |
| 635 | |
| 636 | /* |
| 637 | * If we can't use the console, we need to release |
| 638 | * the console semaphore by hand to avoid flushing |
| 639 | * the buffer. We need to hold the console semaphore |
| 640 | * in order to do this test safely. |
| 641 | */ |
| 642 | if (!can_use_console(cpu)) { |
| 643 | console_locked = 0; |
| 644 | up(&console_sem); |
| 645 | retval = 0; |
| 646 | } |
| 647 | } |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 648 | printk_cpu = UINT_MAX; |
| 649 | spin_unlock(&logbuf_lock); |
| 650 | return retval; |
| 651 | } |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 652 | static const char recursion_bug_msg [] = |
| 653 | KERN_CRIT "BUG: recent printk recursion!\n"; |
| 654 | static int recursion_bug; |
Jiri Kosina | edb123e | 2008-12-04 12:39:49 +0100 | [diff] [blame] | 655 | static int new_text_line = 1; |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 656 | static char printk_buf[1024]; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 657 | |
Dave Young | af91322 | 2009-09-22 16:43:33 -0700 | [diff] [blame] | 658 | int printk_delay_msec __read_mostly; |
| 659 | |
| 660 | static inline void printk_delay(void) |
| 661 | { |
| 662 | if (unlikely(printk_delay_msec)) { |
| 663 | int m = printk_delay_msec; |
| 664 | |
| 665 | while (m--) { |
| 666 | mdelay(1); |
| 667 | touch_nmi_watchdog(); |
| 668 | } |
| 669 | } |
| 670 | } |
| 671 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | asmlinkage int vprintk(const char *fmt, va_list args) |
| 673 | { |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 674 | int printed_len = 0; |
Nick Andrew | 0915930 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 675 | int current_log_level = default_message_loglevel; |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 676 | unsigned long flags; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 677 | int this_cpu; |
| 678 | char *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 680 | boot_delay_msec(); |
Dave Young | af91322 | 2009-09-22 16:43:33 -0700 | [diff] [blame] | 681 | printk_delay(); |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 682 | |
David Howells | fe21773 | 2005-09-06 15:16:34 -0700 | [diff] [blame] | 683 | preempt_disable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | /* This stops the holder of console_sem just where we want him */ |
Mathieu Desnoyers | 1efc5da | 2007-02-10 01:46:29 -0800 | [diff] [blame] | 685 | raw_local_irq_save(flags); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 686 | this_cpu = smp_processor_id(); |
| 687 | |
| 688 | /* |
| 689 | * Ouch, printk recursed into itself! |
| 690 | */ |
| 691 | if (unlikely(printk_cpu == this_cpu)) { |
| 692 | /* |
| 693 | * If a crash is occurring during printk() on this CPU, |
| 694 | * then try to get the crash message out but make sure |
| 695 | * we can't deadlock. Otherwise just return to avoid the |
| 696 | * recursion and return - but flag the recursion so that |
| 697 | * it can be printed at the next appropriate moment: |
| 698 | */ |
| 699 | if (!oops_in_progress) { |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 700 | recursion_bug = 1; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 701 | goto out_restore_irqs; |
| 702 | } |
| 703 | zap_locks(); |
| 704 | } |
| 705 | |
Ingo Molnar | a0f1ccf | 2006-07-03 00:24:58 -0700 | [diff] [blame] | 706 | lockdep_off(); |
| 707 | spin_lock(&logbuf_lock); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 708 | printk_cpu = this_cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 710 | if (recursion_bug) { |
| 711 | recursion_bug = 0; |
| 712 | strcpy(printk_buf, recursion_bug_msg); |
Hiroshi Shimamoto | 26cc271 | 2008-12-19 10:23:03 -0800 | [diff] [blame] | 713 | printed_len = strlen(recursion_bug_msg); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 714 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | /* Emit the output into the temporary buffer */ |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 716 | printed_len += vscnprintf(printk_buf + printed_len, |
Tejun Heo | cf3680b | 2008-02-14 10:32:07 +0900 | [diff] [blame] | 717 | sizeof(printk_buf) - printed_len, fmt, args); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 718 | |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 719 | |
Linus Torvalds | 5fd29d6 | 2009-06-16 10:57:02 -0700 | [diff] [blame] | 720 | p = printk_buf; |
| 721 | |
| 722 | /* Do we have a loglevel in the string? */ |
| 723 | if (p[0] == '<') { |
| 724 | unsigned char c = p[1]; |
| 725 | if (c && p[2] == '>') { |
| 726 | switch (c) { |
| 727 | case '0' ... '7': /* loglevel */ |
| 728 | current_log_level = c - '0'; |
Linus Torvalds | e28d713 | 2009-06-16 11:02:28 -0700 | [diff] [blame] | 729 | /* Fallthrough - make sure we're on a new line */ |
| 730 | case 'd': /* KERN_DEFAULT */ |
Linus Torvalds | 5fd29d6 | 2009-06-16 10:57:02 -0700 | [diff] [blame] | 731 | if (!new_text_line) { |
| 732 | emit_log_char('\n'); |
| 733 | new_text_line = 1; |
| 734 | } |
| 735 | /* Fallthrough - skip the loglevel */ |
| 736 | case 'c': /* KERN_CONT */ |
| 737 | p += 3; |
| 738 | break; |
| 739 | } |
| 740 | } |
| 741 | } |
| 742 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 743 | /* |
| 744 | * Copy the output into log_buf. If the caller didn't provide |
| 745 | * appropriate log level tags, we insert them here |
| 746 | */ |
Linus Torvalds | 5fd29d6 | 2009-06-16 10:57:02 -0700 | [diff] [blame] | 747 | for ( ; *p; p++) { |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 748 | if (new_text_line) { |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 749 | /* Always output the token */ |
| 750 | emit_log_char('<'); |
| 751 | emit_log_char(current_log_level + '0'); |
| 752 | emit_log_char('>'); |
| 753 | printed_len += 3; |
| 754 | new_text_line = 0; |
| 755 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 756 | if (printk_time) { |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 757 | /* Follow the token with the time */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 758 | char tbuf[50], *tp; |
| 759 | unsigned tlen; |
| 760 | unsigned long long t; |
| 761 | unsigned long nanosec_rem; |
| 762 | |
Ingo Molnar | 326e96b | 2008-01-27 08:03:54 +0100 | [diff] [blame] | 763 | t = cpu_clock(printk_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | nanosec_rem = do_div(t, 1000000000); |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 765 | tlen = sprintf(tbuf, "[%5lu.%06lu] ", |
| 766 | (unsigned long) t, |
| 767 | nanosec_rem / 1000); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | |
| 769 | for (tp = tbuf; tp < tbuf + tlen; tp++) |
| 770 | emit_log_char(*tp); |
Guillaume Chazarain | 025510c | 2006-01-08 01:02:41 -0800 | [diff] [blame] | 771 | printed_len += tlen; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 772 | } |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 773 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 774 | if (!*p) |
| 775 | break; |
| 776 | } |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 777 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | emit_log_char(*p); |
| 779 | if (*p == '\n') |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 780 | new_text_line = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | } |
| 782 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 783 | /* |
| 784 | * Try to acquire and then immediately release the |
| 785 | * console semaphore. The release will do all the |
| 786 | * actual magic (print out buffers, wake up klogd, |
| 787 | * etc). |
| 788 | * |
| 789 | * The acquire_console_semaphore_for_printk() function |
| 790 | * will release 'logbuf_lock' regardless of whether it |
| 791 | * actually gets the semaphore or not. |
| 792 | */ |
| 793 | if (acquire_console_semaphore_for_printk(this_cpu)) |
| 794 | release_console_sem(); |
Michael Ellerman | 76a8ad29 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 795 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 796 | lockdep_on(); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 797 | out_restore_irqs: |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 798 | raw_local_irq_restore(flags); |
Michael Ellerman | 76a8ad29 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 799 | |
David Howells | fe21773 | 2005-09-06 15:16:34 -0700 | [diff] [blame] | 800 | preempt_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | return printed_len; |
| 802 | } |
| 803 | EXPORT_SYMBOL(printk); |
| 804 | EXPORT_SYMBOL(vprintk); |
| 805 | |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 806 | #else |
| 807 | |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 808 | static void call_console_drivers(unsigned start, unsigned end) |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 809 | { |
| 810 | } |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 811 | |
| 812 | #endif |
| 813 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 814 | static int __add_preferred_console(char *name, int idx, char *options, |
| 815 | char *brl_options) |
| 816 | { |
| 817 | struct console_cmdline *c; |
| 818 | int i; |
| 819 | |
| 820 | /* |
| 821 | * See if this tty is not yet registered, and |
| 822 | * if we have a slot free. |
| 823 | */ |
| 824 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| 825 | if (strcmp(console_cmdline[i].name, name) == 0 && |
| 826 | console_cmdline[i].index == idx) { |
| 827 | if (!brl_options) |
| 828 | selected_console = i; |
| 829 | return 0; |
| 830 | } |
| 831 | if (i == MAX_CMDLINECONSOLES) |
| 832 | return -E2BIG; |
| 833 | if (!brl_options) |
| 834 | selected_console = i; |
| 835 | c = &console_cmdline[i]; |
| 836 | strlcpy(c->name, name, sizeof(c->name)); |
| 837 | c->options = options; |
| 838 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 839 | c->brl_options = brl_options; |
| 840 | #endif |
| 841 | c->index = idx; |
| 842 | return 0; |
| 843 | } |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 844 | /* |
| 845 | * Set up a list of consoles. Called from init/main.c |
| 846 | */ |
| 847 | static int __init console_setup(char *str) |
| 848 | { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 849 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 850 | char *s, *options, *brl_options = NULL; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 851 | int idx; |
| 852 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 853 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 854 | if (!memcmp(str, "brl,", 4)) { |
| 855 | brl_options = ""; |
| 856 | str += 4; |
| 857 | } else if (!memcmp(str, "brl=", 4)) { |
| 858 | brl_options = str + 4; |
| 859 | str = strchr(brl_options, ','); |
| 860 | if (!str) { |
| 861 | printk(KERN_ERR "need port name after brl=\n"); |
| 862 | return 1; |
| 863 | } |
| 864 | *(str++) = 0; |
| 865 | } |
| 866 | #endif |
| 867 | |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 868 | /* |
| 869 | * Decode str into name, index, options. |
| 870 | */ |
| 871 | if (str[0] >= '0' && str[0] <= '9') { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 872 | strcpy(buf, "ttyS"); |
| 873 | strncpy(buf + 4, str, sizeof(buf) - 5); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 874 | } else { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 875 | strncpy(buf, str, sizeof(buf) - 1); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 876 | } |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 877 | buf[sizeof(buf) - 1] = 0; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 878 | if ((options = strchr(str, ',')) != NULL) |
| 879 | *(options++) = 0; |
| 880 | #ifdef __sparc__ |
| 881 | if (!strcmp(str, "ttya")) |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 882 | strcpy(buf, "ttyS0"); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 883 | if (!strcmp(str, "ttyb")) |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 884 | strcpy(buf, "ttyS1"); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 885 | #endif |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 886 | for (s = buf; *s; s++) |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 887 | if ((*s >= '0' && *s <= '9') || *s == ',') |
| 888 | break; |
| 889 | idx = simple_strtoul(s, NULL, 10); |
| 890 | *s = 0; |
| 891 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 892 | __add_preferred_console(buf, idx, options, brl_options); |
Markus Armbruster | 9e124fe | 2008-05-26 23:31:07 +0100 | [diff] [blame] | 893 | console_set_on_cmdline = 1; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 894 | return 1; |
| 895 | } |
| 896 | __setup("console=", console_setup); |
| 897 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | /** |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 899 | * add_preferred_console - add a device to the list of preferred consoles. |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 900 | * @name: device name |
| 901 | * @idx: device index |
| 902 | * @options: options for this console |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 903 | * |
| 904 | * The last preferred console added will be used for kernel messages |
| 905 | * and stdin/out/err for init. Normally this is used by console_setup |
| 906 | * above to handle user-supplied console arguments; however it can also |
| 907 | * be used by arch-specific code either to override the user or more |
| 908 | * commonly to provide a default console (ie from PROM variables) when |
| 909 | * the user has not supplied one. |
| 910 | */ |
David S. Miller | fb445ee | 2007-12-29 01:19:49 -0800 | [diff] [blame] | 911 | int add_preferred_console(char *name, int idx, char *options) |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 912 | { |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 913 | return __add_preferred_console(name, idx, options, NULL); |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 914 | } |
| 915 | |
Daniel Ritz | b6b1d87 | 2007-08-03 16:07:43 +0200 | [diff] [blame] | 916 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 917 | { |
| 918 | struct console_cmdline *c; |
| 919 | int i; |
| 920 | |
| 921 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| 922 | if (strcmp(console_cmdline[i].name, name) == 0 && |
| 923 | console_cmdline[i].index == idx) { |
| 924 | c = &console_cmdline[i]; |
Markus Armbruster | f735295 | 2008-04-30 00:54:52 -0700 | [diff] [blame] | 925 | strlcpy(c->name, name_new, sizeof(c->name)); |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 926 | c->name[sizeof(c->name) - 1] = 0; |
| 927 | c->options = options; |
| 928 | c->index = idx_new; |
| 929 | return i; |
| 930 | } |
| 931 | /* not found */ |
| 932 | return -1; |
| 933 | } |
| 934 | |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 935 | int console_suspend_enabled = 1; |
| 936 | EXPORT_SYMBOL(console_suspend_enabled); |
| 937 | |
| 938 | static int __init console_suspend_disable(char *str) |
| 939 | { |
| 940 | console_suspend_enabled = 0; |
| 941 | return 1; |
| 942 | } |
| 943 | __setup("no_console_suspend", console_suspend_disable); |
| 944 | |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 945 | /** |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 946 | * suspend_console - suspend the console subsystem |
| 947 | * |
| 948 | * This disables printk() while we go into suspend states |
| 949 | */ |
| 950 | void suspend_console(void) |
| 951 | { |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 952 | if (!console_suspend_enabled) |
| 953 | return; |
Pavel Machek | 0d63081 | 2008-07-23 21:28:32 -0700 | [diff] [blame] | 954 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 955 | acquire_console_sem(); |
| 956 | console_suspended = 1; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 957 | up(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 958 | } |
| 959 | |
| 960 | void resume_console(void) |
| 961 | { |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 962 | if (!console_suspend_enabled) |
| 963 | return; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 964 | down(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 965 | console_suspended = 0; |
| 966 | release_console_sem(); |
| 967 | } |
| 968 | |
| 969 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | * acquire_console_sem - lock the console system for exclusive use. |
| 971 | * |
| 972 | * Acquires a semaphore which guarantees that the caller has |
| 973 | * exclusive access to the console system and the console_drivers list. |
| 974 | * |
| 975 | * Can sleep, returns nothing. |
| 976 | */ |
| 977 | void acquire_console_sem(void) |
| 978 | { |
Eric Sesterhenn | 8abd8e2 | 2006-04-01 01:21:17 +0200 | [diff] [blame] | 979 | BUG_ON(in_interrupt()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 980 | down(&console_sem); |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 981 | if (console_suspended) |
| 982 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | console_locked = 1; |
| 984 | console_may_schedule = 1; |
| 985 | } |
| 986 | EXPORT_SYMBOL(acquire_console_sem); |
| 987 | |
| 988 | int try_acquire_console_sem(void) |
| 989 | { |
| 990 | if (down_trylock(&console_sem)) |
| 991 | return -1; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 992 | if (console_suspended) { |
| 993 | up(&console_sem); |
| 994 | return -1; |
| 995 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 996 | console_locked = 1; |
| 997 | console_may_schedule = 0; |
| 998 | return 0; |
| 999 | } |
| 1000 | EXPORT_SYMBOL(try_acquire_console_sem); |
| 1001 | |
| 1002 | int is_console_locked(void) |
| 1003 | { |
| 1004 | return console_locked; |
| 1005 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1006 | |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1007 | static DEFINE_PER_CPU(int, printk_pending); |
| 1008 | |
| 1009 | void printk_tick(void) |
| 1010 | { |
| 1011 | if (__get_cpu_var(printk_pending)) { |
| 1012 | __get_cpu_var(printk_pending) = 0; |
| 1013 | wake_up_interruptible(&log_wait); |
| 1014 | } |
| 1015 | } |
| 1016 | |
| 1017 | int printk_needs_cpu(int cpu) |
| 1018 | { |
| 1019 | return per_cpu(printk_pending, cpu); |
| 1020 | } |
| 1021 | |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1022 | void wake_up_klogd(void) |
| 1023 | { |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1024 | if (waitqueue_active(&log_wait)) |
Peter Zijlstra | fa33507 | 2008-08-20 09:31:26 +0200 | [diff] [blame] | 1025 | __raw_get_cpu_var(printk_pending) = 1; |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1026 | } |
| 1027 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | /** |
| 1029 | * release_console_sem - unlock the console system |
| 1030 | * |
| 1031 | * Releases the semaphore which the caller holds on the console system |
| 1032 | * and the console driver list. |
| 1033 | * |
| 1034 | * While the semaphore was held, console output may have been buffered |
| 1035 | * by printk(). If this is the case, release_console_sem() emits |
| 1036 | * the output prior to releasing the semaphore. |
| 1037 | * |
| 1038 | * If there is output waiting for klogd, we wake it up. |
| 1039 | * |
| 1040 | * release_console_sem() may be called from any context. |
| 1041 | */ |
| 1042 | void release_console_sem(void) |
| 1043 | { |
| 1044 | unsigned long flags; |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 1045 | unsigned _con_start, _log_end; |
| 1046 | unsigned wake_klogd = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1048 | if (console_suspended) { |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1049 | up(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1050 | return; |
| 1051 | } |
Antonino A. Daplas | 78944e54 | 2006-08-05 12:14:16 -0700 | [diff] [blame] | 1052 | |
| 1053 | console_may_schedule = 0; |
| 1054 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1055 | for ( ; ; ) { |
| 1056 | spin_lock_irqsave(&logbuf_lock, flags); |
| 1057 | wake_klogd |= log_start - log_end; |
| 1058 | if (con_start == log_end) |
| 1059 | break; /* Nothing to print */ |
| 1060 | _con_start = con_start; |
| 1061 | _log_end = log_end; |
| 1062 | con_start = log_end; /* Flush */ |
| 1063 | spin_unlock(&logbuf_lock); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1064 | stop_critical_timings(); /* don't trace print latency */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | call_console_drivers(_con_start, _log_end); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1066 | start_critical_timings(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1067 | local_irq_restore(flags); |
| 1068 | } |
| 1069 | console_locked = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | up(&console_sem); |
| 1071 | spin_unlock_irqrestore(&logbuf_lock, flags); |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1072 | if (wake_klogd) |
| 1073 | wake_up_klogd(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1074 | } |
| 1075 | EXPORT_SYMBOL(release_console_sem); |
| 1076 | |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 1077 | /** |
| 1078 | * console_conditional_schedule - yield the CPU if required |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1079 | * |
| 1080 | * If the console code is currently allowed to sleep, and |
| 1081 | * if this CPU should yield the CPU to another task, do |
| 1082 | * so here. |
| 1083 | * |
| 1084 | * Must be called within acquire_console_sem(). |
| 1085 | */ |
| 1086 | void __sched console_conditional_schedule(void) |
| 1087 | { |
| 1088 | if (console_may_schedule) |
| 1089 | cond_resched(); |
| 1090 | } |
| 1091 | EXPORT_SYMBOL(console_conditional_schedule); |
| 1092 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1093 | void console_unblank(void) |
| 1094 | { |
| 1095 | struct console *c; |
| 1096 | |
| 1097 | /* |
| 1098 | * console_unblank can no longer be called in interrupt context unless |
| 1099 | * oops_in_progress is set to 1.. |
| 1100 | */ |
| 1101 | if (oops_in_progress) { |
| 1102 | if (down_trylock(&console_sem) != 0) |
| 1103 | return; |
| 1104 | } else |
| 1105 | acquire_console_sem(); |
| 1106 | |
| 1107 | console_locked = 1; |
| 1108 | console_may_schedule = 0; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1109 | for_each_console(c) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | if ((c->flags & CON_ENABLED) && c->unblank) |
| 1111 | c->unblank(); |
| 1112 | release_console_sem(); |
| 1113 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1114 | |
| 1115 | /* |
| 1116 | * Return the console tty driver structure and its associated index |
| 1117 | */ |
| 1118 | struct tty_driver *console_device(int *index) |
| 1119 | { |
| 1120 | struct console *c; |
| 1121 | struct tty_driver *driver = NULL; |
| 1122 | |
| 1123 | acquire_console_sem(); |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1124 | for_each_console(c) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | if (!c->device) |
| 1126 | continue; |
| 1127 | driver = c->device(c, index); |
| 1128 | if (driver) |
| 1129 | break; |
| 1130 | } |
| 1131 | release_console_sem(); |
| 1132 | return driver; |
| 1133 | } |
| 1134 | |
| 1135 | /* |
| 1136 | * Prevent further output on the passed console device so that (for example) |
| 1137 | * serial drivers can disable console output before suspending a port, and can |
| 1138 | * re-enable output afterwards. |
| 1139 | */ |
| 1140 | void console_stop(struct console *console) |
| 1141 | { |
| 1142 | acquire_console_sem(); |
| 1143 | console->flags &= ~CON_ENABLED; |
| 1144 | release_console_sem(); |
| 1145 | } |
| 1146 | EXPORT_SYMBOL(console_stop); |
| 1147 | |
| 1148 | void console_start(struct console *console) |
| 1149 | { |
| 1150 | acquire_console_sem(); |
| 1151 | console->flags |= CON_ENABLED; |
| 1152 | release_console_sem(); |
| 1153 | } |
| 1154 | EXPORT_SYMBOL(console_start); |
| 1155 | |
| 1156 | /* |
| 1157 | * The console driver calls this routine during kernel initialization |
| 1158 | * to register the console printing procedure with printk() and to |
| 1159 | * print any messages that were printed by the kernel before the |
| 1160 | * console driver was initialized. |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1161 | * |
| 1162 | * This can happen pretty early during the boot process (because of |
| 1163 | * early_printk) - sometimes before setup_arch() completes - be careful |
| 1164 | * of what kernel features are used - they may not be initialised yet. |
| 1165 | * |
| 1166 | * There are two types of consoles - bootconsoles (early_printk) and |
| 1167 | * "real" consoles (everything which is not a bootconsole) which are |
| 1168 | * handled differently. |
| 1169 | * - Any number of bootconsoles can be registered at any time. |
| 1170 | * - As soon as a "real" console is registered, all bootconsoles |
| 1171 | * will be unregistered automatically. |
| 1172 | * - Once a "real" console is registered, any attempt to register a |
| 1173 | * bootconsoles will be rejected |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1174 | */ |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1175 | void register_console(struct console *newcon) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1177 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1178 | unsigned long flags; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1179 | struct console *bcon = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1180 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1181 | /* |
| 1182 | * before we register a new CON_BOOT console, make sure we don't |
| 1183 | * already have a valid console |
| 1184 | */ |
| 1185 | if (console_drivers && newcon->flags & CON_BOOT) { |
| 1186 | /* find the last or real console */ |
| 1187 | for_each_console(bcon) { |
| 1188 | if (!(bcon->flags & CON_BOOT)) { |
| 1189 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", |
| 1190 | newcon->name, newcon->index); |
| 1191 | return; |
| 1192 | } |
| 1193 | } |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 1194 | } |
| 1195 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1196 | if (console_drivers && console_drivers->flags & CON_BOOT) |
| 1197 | bcon = console_drivers; |
| 1198 | |
| 1199 | if (preferred_console < 0 || bcon || !console_drivers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | preferred_console = selected_console; |
| 1201 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1202 | if (newcon->early_setup) |
| 1203 | newcon->early_setup(); |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 1204 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1205 | /* |
| 1206 | * See if we want to use this console driver. If we |
| 1207 | * didn't select a console we take the first one |
| 1208 | * that registers here. |
| 1209 | */ |
| 1210 | if (preferred_console < 0) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1211 | if (newcon->index < 0) |
| 1212 | newcon->index = 0; |
| 1213 | if (newcon->setup == NULL || |
| 1214 | newcon->setup(newcon, NULL) == 0) { |
| 1215 | newcon->flags |= CON_ENABLED; |
| 1216 | if (newcon->device) { |
| 1217 | newcon->flags |= CON_CONSDEV; |
Jan Kiszka | cd3a1b8 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1218 | preferred_console = 0; |
| 1219 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | } |
| 1221 | } |
| 1222 | |
| 1223 | /* |
| 1224 | * See if this console matches one we selected on |
| 1225 | * the command line. |
| 1226 | */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1227 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
| 1228 | i++) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1229 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1230 | continue; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1231 | if (newcon->index >= 0 && |
| 1232 | newcon->index != console_cmdline[i].index) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | continue; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1234 | if (newcon->index < 0) |
| 1235 | newcon->index = console_cmdline[i].index; |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1236 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1237 | if (console_cmdline[i].brl_options) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1238 | newcon->flags |= CON_BRL; |
| 1239 | braille_register_console(newcon, |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1240 | console_cmdline[i].index, |
| 1241 | console_cmdline[i].options, |
| 1242 | console_cmdline[i].brl_options); |
| 1243 | return; |
| 1244 | } |
| 1245 | #endif |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1246 | if (newcon->setup && |
| 1247 | newcon->setup(newcon, console_cmdline[i].options) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1248 | break; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1249 | newcon->flags |= CON_ENABLED; |
| 1250 | newcon->index = console_cmdline[i].index; |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1251 | if (i == selected_console) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1252 | newcon->flags |= CON_CONSDEV; |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1253 | preferred_console = selected_console; |
| 1254 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1255 | break; |
| 1256 | } |
| 1257 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1258 | if (!(newcon->flags & CON_ENABLED)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1259 | return; |
| 1260 | |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 1261 | /* |
| 1262 | * If we have a bootconsole, and are switching to a real console, |
| 1263 | * don't print everything out again, since when the boot console, and |
| 1264 | * the real console are the same physical device, it's annoying to |
| 1265 | * see the beginning boot messages twice |
| 1266 | */ |
| 1267 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1268 | newcon->flags &= ~CON_PRINTBUFFER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | |
| 1270 | /* |
| 1271 | * Put this console in the list - keep the |
| 1272 | * preferred driver at the head of the list. |
| 1273 | */ |
| 1274 | acquire_console_sem(); |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1275 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
| 1276 | newcon->next = console_drivers; |
| 1277 | console_drivers = newcon; |
| 1278 | if (newcon->next) |
| 1279 | newcon->next->flags &= ~CON_CONSDEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1280 | } else { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1281 | newcon->next = console_drivers->next; |
| 1282 | console_drivers->next = newcon; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1283 | } |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1284 | if (newcon->flags & CON_PRINTBUFFER) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1285 | /* |
| 1286 | * release_console_sem() will print out the buffered messages |
| 1287 | * for us. |
| 1288 | */ |
| 1289 | spin_lock_irqsave(&logbuf_lock, flags); |
| 1290 | con_start = log_start; |
| 1291 | spin_unlock_irqrestore(&logbuf_lock, flags); |
| 1292 | } |
| 1293 | release_console_sem(); |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 1294 | |
| 1295 | /* |
| 1296 | * By unregistering the bootconsoles after we enable the real console |
| 1297 | * we get the "console xxx enabled" message on all the consoles - |
| 1298 | * boot consoles, real consoles, etc - this is to ensure that end |
| 1299 | * users know there might be something in the kernel's log buffer that |
| 1300 | * went to the bootconsole (that they do not see on the real console) |
| 1301 | */ |
| 1302 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) { |
| 1303 | /* we need to iterate through twice, to make sure we print |
| 1304 | * everything out, before we unregister the console(s) |
| 1305 | */ |
| 1306 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", |
| 1307 | newcon->name, newcon->index); |
| 1308 | for_each_console(bcon) |
| 1309 | if (bcon->flags & CON_BOOT) |
| 1310 | unregister_console(bcon); |
| 1311 | } else { |
| 1312 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", |
| 1313 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
| 1314 | newcon->name, newcon->index); |
| 1315 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1316 | } |
| 1317 | EXPORT_SYMBOL(register_console); |
| 1318 | |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1319 | int unregister_console(struct console *console) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1320 | { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1321 | struct console *a, *b; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1322 | int res = 1; |
| 1323 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1324 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1325 | if (console->flags & CON_BRL) |
| 1326 | return braille_unregister_console(console); |
| 1327 | #endif |
| 1328 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1329 | acquire_console_sem(); |
| 1330 | if (console_drivers == console) { |
| 1331 | console_drivers=console->next; |
| 1332 | res = 0; |
Benjamin Herrenschmidt | e9b15b5 | 2005-11-23 13:37:44 -0800 | [diff] [blame] | 1333 | } else if (console_drivers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1334 | for (a=console_drivers->next, b=console_drivers ; |
| 1335 | a; b=a, a=b->next) { |
| 1336 | if (a == console) { |
| 1337 | b->next = a->next; |
| 1338 | res = 0; |
| 1339 | break; |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1340 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | } |
| 1342 | } |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1343 | |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 1344 | /* |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1345 | * If this isn't the last console and it has CON_CONSDEV set, we |
| 1346 | * need to set it on the next preferred console. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1347 | */ |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 1348 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1349 | console_drivers->flags |= CON_CONSDEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1350 | |
| 1351 | release_console_sem(); |
| 1352 | return res; |
| 1353 | } |
| 1354 | EXPORT_SYMBOL(unregister_console); |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1355 | |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 1356 | static int __init disable_boot_consoles(void) |
| 1357 | { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1358 | struct console *con; |
| 1359 | |
| 1360 | for_each_console(con) { |
| 1361 | if (con->flags & CON_BOOT) { |
Robin Getz | cb00e99 | 2007-08-21 23:14:58 -0400 | [diff] [blame] | 1362 | printk(KERN_INFO "turn off boot console %s%d\n", |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1363 | con->name, con->index); |
Sonic Zhang | 42c2c8c | 2009-08-06 15:58:11 -0700 | [diff] [blame] | 1364 | unregister_console(con); |
Robin Getz | cb00e99 | 2007-08-21 23:14:58 -0400 | [diff] [blame] | 1365 | } |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 1366 | } |
| 1367 | return 0; |
| 1368 | } |
| 1369 | late_initcall(disable_boot_consoles); |
| 1370 | |
Joe Perches | 7ef3d2f | 2008-02-08 04:21:25 -0800 | [diff] [blame] | 1371 | #if defined CONFIG_PRINTK |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 1372 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1373 | /* |
| 1374 | * printk rate limiting, lifted from the networking subsystem. |
| 1375 | * |
Uwe Kleine-König | 641de9d | 2008-07-29 22:33:38 -0700 | [diff] [blame] | 1376 | * This enforces a rate limit: not more than 10 kernel messages |
| 1377 | * every 5s to make a denial-of-service attack impossible. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | */ |
Uwe Kleine-König | 641de9d | 2008-07-29 22:33:38 -0700 | [diff] [blame] | 1379 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
| 1380 | |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 1381 | int __printk_ratelimit(const char *func) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1382 | { |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 1383 | return ___ratelimit(&printk_ratelimit_state, func); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1384 | } |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 1385 | EXPORT_SYMBOL(__printk_ratelimit); |
Andrew Morton | f46c483 | 2006-11-02 22:07:16 -0800 | [diff] [blame] | 1386 | |
| 1387 | /** |
| 1388 | * printk_timed_ratelimit - caller-controlled printk ratelimiting |
| 1389 | * @caller_jiffies: pointer to caller's state |
| 1390 | * @interval_msecs: minimum interval between prints |
| 1391 | * |
| 1392 | * printk_timed_ratelimit() returns true if more than @interval_msecs |
| 1393 | * milliseconds have elapsed since the last time printk_timed_ratelimit() |
| 1394 | * returned true. |
| 1395 | */ |
| 1396 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, |
| 1397 | unsigned int interval_msecs) |
| 1398 | { |
Guillaume Knispel | f2d28a2 | 2009-03-17 16:18:42 +0100 | [diff] [blame] | 1399 | if (*caller_jiffies == 0 |
| 1400 | || !time_in_range(jiffies, *caller_jiffies, |
| 1401 | *caller_jiffies |
| 1402 | + msecs_to_jiffies(interval_msecs))) { |
| 1403 | *caller_jiffies = jiffies; |
Andrew Morton | f46c483 | 2006-11-02 22:07:16 -0800 | [diff] [blame] | 1404 | return true; |
| 1405 | } |
| 1406 | return false; |
| 1407 | } |
| 1408 | EXPORT_SYMBOL(printk_timed_ratelimit); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1409 | |
| 1410 | static DEFINE_SPINLOCK(dump_list_lock); |
| 1411 | static LIST_HEAD(dump_list); |
| 1412 | |
| 1413 | /** |
| 1414 | * kmsg_dump_register - register a kernel log dumper. |
Randy Dunlap | 6485536 | 2009-12-17 15:27:27 -0800 | [diff] [blame] | 1415 | * @dumper: pointer to the kmsg_dumper structure |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1416 | * |
| 1417 | * Adds a kernel log dumper to the system. The dump callback in the |
| 1418 | * structure will be called when the kernel oopses or panics and must be |
| 1419 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. |
| 1420 | */ |
| 1421 | int kmsg_dump_register(struct kmsg_dumper *dumper) |
| 1422 | { |
| 1423 | unsigned long flags; |
| 1424 | int err = -EBUSY; |
| 1425 | |
| 1426 | /* The dump callback needs to be set */ |
| 1427 | if (!dumper->dump) |
| 1428 | return -EINVAL; |
| 1429 | |
| 1430 | spin_lock_irqsave(&dump_list_lock, flags); |
| 1431 | /* Don't allow registering multiple times */ |
| 1432 | if (!dumper->registered) { |
| 1433 | dumper->registered = 1; |
| 1434 | list_add_tail(&dumper->list, &dump_list); |
| 1435 | err = 0; |
| 1436 | } |
| 1437 | spin_unlock_irqrestore(&dump_list_lock, flags); |
| 1438 | |
| 1439 | return err; |
| 1440 | } |
| 1441 | EXPORT_SYMBOL_GPL(kmsg_dump_register); |
| 1442 | |
| 1443 | /** |
| 1444 | * kmsg_dump_unregister - unregister a kmsg dumper. |
Randy Dunlap | 6485536 | 2009-12-17 15:27:27 -0800 | [diff] [blame] | 1445 | * @dumper: pointer to the kmsg_dumper structure |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1446 | * |
| 1447 | * Removes a dump device from the system. Returns zero on success and |
| 1448 | * %-EINVAL otherwise. |
| 1449 | */ |
| 1450 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) |
| 1451 | { |
| 1452 | unsigned long flags; |
| 1453 | int err = -EINVAL; |
| 1454 | |
| 1455 | spin_lock_irqsave(&dump_list_lock, flags); |
| 1456 | if (dumper->registered) { |
| 1457 | dumper->registered = 0; |
| 1458 | list_del(&dumper->list); |
| 1459 | err = 0; |
| 1460 | } |
| 1461 | spin_unlock_irqrestore(&dump_list_lock, flags); |
| 1462 | |
| 1463 | return err; |
| 1464 | } |
| 1465 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); |
| 1466 | |
| 1467 | static const char const *kmsg_reasons[] = { |
| 1468 | [KMSG_DUMP_OOPS] = "oops", |
| 1469 | [KMSG_DUMP_PANIC] = "panic", |
KOSAKI Motohiro | 0f4bd46 | 2009-12-22 03:15:43 +0000 | [diff] [blame] | 1470 | [KMSG_DUMP_KEXEC] = "kexec", |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1471 | }; |
| 1472 | |
| 1473 | static const char *kmsg_to_str(enum kmsg_dump_reason reason) |
| 1474 | { |
| 1475 | if (reason >= ARRAY_SIZE(kmsg_reasons) || reason < 0) |
| 1476 | return "unknown"; |
| 1477 | |
| 1478 | return kmsg_reasons[reason]; |
| 1479 | } |
| 1480 | |
| 1481 | /** |
| 1482 | * kmsg_dump - dump kernel log to kernel message dumpers. |
| 1483 | * @reason: the reason (oops, panic etc) for dumping |
| 1484 | * |
| 1485 | * Iterate through each of the dump devices and call the oops/panic |
| 1486 | * callbacks with the log buffer. |
| 1487 | */ |
| 1488 | void kmsg_dump(enum kmsg_dump_reason reason) |
| 1489 | { |
| 1490 | unsigned long end; |
| 1491 | unsigned chars; |
| 1492 | struct kmsg_dumper *dumper; |
| 1493 | const char *s1, *s2; |
| 1494 | unsigned long l1, l2; |
| 1495 | unsigned long flags; |
| 1496 | |
| 1497 | /* Theoretically, the log could move on after we do this, but |
| 1498 | there's not a lot we can do about that. The new messages |
| 1499 | will overwrite the start of what we dump. */ |
| 1500 | spin_lock_irqsave(&logbuf_lock, flags); |
| 1501 | end = log_end & LOG_BUF_MASK; |
| 1502 | chars = logged_chars; |
| 1503 | spin_unlock_irqrestore(&logbuf_lock, flags); |
| 1504 | |
| 1505 | if (logged_chars > end) { |
| 1506 | s1 = log_buf + log_buf_len - logged_chars + end; |
| 1507 | l1 = logged_chars - end; |
| 1508 | |
| 1509 | s2 = log_buf; |
| 1510 | l2 = end; |
| 1511 | } else { |
| 1512 | s1 = ""; |
| 1513 | l1 = 0; |
| 1514 | |
| 1515 | s2 = log_buf + end - logged_chars; |
| 1516 | l2 = logged_chars; |
| 1517 | } |
| 1518 | |
| 1519 | if (!spin_trylock_irqsave(&dump_list_lock, flags)) { |
| 1520 | printk(KERN_ERR "dump_kmsg: dump list lock is held during %s, skipping dump\n", |
| 1521 | kmsg_to_str(reason)); |
| 1522 | return; |
| 1523 | } |
| 1524 | list_for_each_entry(dumper, &dump_list, list) |
| 1525 | dumper->dump(dumper, reason, s1, l1, s2, l2); |
| 1526 | spin_unlock_irqrestore(&dump_list_lock, flags); |
| 1527 | } |
Joe Perches | 7ef3d2f | 2008-02-08 04:21:25 -0800 | [diff] [blame] | 1528 | #endif |