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> |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 34 | #include <linux/memblock.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/syscalls.h> |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 36 | #include <linux/kexec.h> |
Jason Wessel | d37d39a | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 37 | #include <linux/kdb.h> |
Ingo Molnar | 3fff4c4 | 2009-09-22 16:18:09 +0200 | [diff] [blame] | 38 | #include <linux/ratelimit.h> |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 39 | #include <linux/kmsg_dump.h> |
Kees Cook | 0023459 | 2010-02-03 15:36:43 -0800 | [diff] [blame] | 40 | #include <linux/syslog.h> |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 41 | #include <linux/cpu.h> |
| 42 | #include <linux/notifier.h> |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 43 | #include <linux/rculist.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | |
| 45 | #include <asm/uaccess.h> |
| 46 | |
Ingo Molnar | 076f977 | 2008-01-30 13:33:06 +0100 | [diff] [blame] | 47 | /* |
| 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.. */ |
Mandeep Singh Baines | 5af5bcb | 2011-03-22 16:34:23 -0700 | [diff] [blame] | 57 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | /* |
Patrick Pletscher | 0bbfb7c | 2007-02-17 20:10:16 +0100 | [diff] [blame] | 73 | * 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] | 74 | * their unblank() callback or not. So let's export it. |
| 75 | */ |
| 76 | int oops_in_progress; |
| 77 | EXPORT_SYMBOL(oops_in_progress); |
| 78 | |
| 79 | /* |
| 80 | * console_sem protects the console_drivers list, and also |
| 81 | * provides serialisation for access to the entire console |
| 82 | * driver system. |
| 83 | */ |
Thomas Gleixner | 5b8c4f2 | 2010-09-07 14:33:43 +0000 | [diff] [blame] | 84 | static DEFINE_SEMAPHORE(console_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | struct console *console_drivers; |
Ingo Molnar | a29d1cf | 2008-06-02 13:19:08 +0200 | [diff] [blame] | 86 | EXPORT_SYMBOL_GPL(console_drivers); |
| 87 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | /* |
| 89 | * This is used for debugging the mess that is the VT code by |
| 90 | * keeping track if we have the console semaphore held. It's |
| 91 | * definitely not the perfect debug tool (we don't know if _WE_ |
| 92 | * hold it are racing, but it helps tracking those weird code |
| 93 | * path in the console code where we end up in places I want |
| 94 | * locked without the console sempahore held |
| 95 | */ |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 96 | static int console_locked, console_suspended; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | |
| 98 | /* |
| 99 | * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars |
| 100 | * It is also used in interesting ways to provide interlocking in |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 101 | * console_unlock();. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | */ |
| 103 | static DEFINE_SPINLOCK(logbuf_lock); |
| 104 | |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 105 | #define LOG_BUF_MASK (log_buf_len-1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) |
| 107 | |
| 108 | /* |
| 109 | * The indices into log_buf are not constrained to log_buf_len - they |
| 110 | * must be masked before subscripting |
| 111 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 112 | static unsigned log_start; /* Index into log_buf: next char to be read by syslog() */ |
| 113 | static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */ |
| 114 | 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] | 115 | |
| 116 | /* |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 117 | * If exclusive_console is non-NULL then only this console is to be printed to. |
| 118 | */ |
| 119 | static struct console *exclusive_console; |
| 120 | |
| 121 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | * Array of consoles built from command line options (console=) |
| 123 | */ |
| 124 | struct console_cmdline |
| 125 | { |
| 126 | char name[8]; /* Name of the driver */ |
| 127 | int index; /* Minor dev. to use */ |
| 128 | char *options; /* Options for the driver */ |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 129 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 130 | char *brl_options; /* Options for braille driver */ |
| 131 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | }; |
| 133 | |
| 134 | #define MAX_CMDLINECONSOLES 8 |
| 135 | |
| 136 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; |
| 137 | static int selected_console = -1; |
| 138 | static int preferred_console = -1; |
Markus Armbruster | 9e124fe | 2008-05-26 23:31:07 +0100 | [diff] [blame] | 139 | int console_set_on_cmdline; |
| 140 | EXPORT_SYMBOL(console_set_on_cmdline); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | |
| 142 | /* Flag: console code may call schedule() */ |
| 143 | static int console_may_schedule; |
| 144 | |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 145 | #ifdef CONFIG_PRINTK |
| 146 | |
| 147 | static char __log_buf[__LOG_BUF_LEN]; |
| 148 | static char *log_buf = __log_buf; |
| 149 | static int log_buf_len = __LOG_BUF_LEN; |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 150 | static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ |
Gustavo F. Padovan | cea8388 | 2010-03-05 13:42:58 -0800 | [diff] [blame] | 151 | static int saved_console_loglevel = -1; |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 152 | |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 153 | #ifdef CONFIG_KEXEC |
| 154 | /* |
| 155 | * This appends the listed symbols to /proc/vmcoreinfo |
| 156 | * |
| 157 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to |
| 158 | * obtain access to symbols that are otherwise very difficult to locate. These |
| 159 | * symbols are specifically used so that utilities can access and extract the |
| 160 | * dmesg log from a vmcore file after a crash. |
| 161 | */ |
| 162 | void log_buf_kexec_setup(void) |
| 163 | { |
| 164 | VMCOREINFO_SYMBOL(log_buf); |
| 165 | VMCOREINFO_SYMBOL(log_end); |
| 166 | VMCOREINFO_SYMBOL(log_buf_len); |
| 167 | VMCOREINFO_SYMBOL(logged_chars); |
| 168 | } |
| 169 | #endif |
| 170 | |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 171 | /* requested log_buf_len from kernel cmdline */ |
| 172 | static unsigned long __initdata new_log_buf_len; |
| 173 | |
| 174 | /* save requested log_buf_len since it's too early to process it */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | static int __init log_buf_len_setup(char *str) |
| 176 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 177 | unsigned size = memparse(str, &str); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | |
| 179 | if (size) |
| 180 | size = roundup_pow_of_two(size); |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 181 | if (size > log_buf_len) |
| 182 | new_log_buf_len = size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 184 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | } |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 186 | early_param("log_buf_len", log_buf_len_setup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 188 | void __init setup_log_buf(int early) |
| 189 | { |
| 190 | unsigned long flags; |
| 191 | unsigned start, dest_idx, offset; |
| 192 | char *new_log_buf; |
| 193 | int free; |
| 194 | |
| 195 | if (!new_log_buf_len) |
| 196 | return; |
| 197 | |
| 198 | if (early) { |
| 199 | unsigned long mem; |
| 200 | |
| 201 | mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); |
| 202 | if (mem == MEMBLOCK_ERROR) |
| 203 | return; |
| 204 | new_log_buf = __va(mem); |
| 205 | } else { |
| 206 | new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); |
| 207 | } |
| 208 | |
| 209 | if (unlikely(!new_log_buf)) { |
| 210 | pr_err("log_buf_len: %ld bytes not available\n", |
| 211 | new_log_buf_len); |
| 212 | return; |
| 213 | } |
| 214 | |
| 215 | spin_lock_irqsave(&logbuf_lock, flags); |
| 216 | log_buf_len = new_log_buf_len; |
| 217 | log_buf = new_log_buf; |
| 218 | new_log_buf_len = 0; |
| 219 | free = __LOG_BUF_LEN - log_end; |
| 220 | |
| 221 | offset = start = min(con_start, log_start); |
| 222 | dest_idx = 0; |
| 223 | while (start != log_end) { |
| 224 | unsigned log_idx_mask = start & (__LOG_BUF_LEN - 1); |
| 225 | |
| 226 | log_buf[dest_idx] = __log_buf[log_idx_mask]; |
| 227 | start++; |
| 228 | dest_idx++; |
| 229 | } |
| 230 | log_start -= offset; |
| 231 | con_start -= offset; |
| 232 | log_end -= offset; |
| 233 | spin_unlock_irqrestore(&logbuf_lock, flags); |
| 234 | |
| 235 | pr_info("log_buf_len: %d\n", log_buf_len); |
| 236 | pr_info("early log buf free: %d(%d%%)\n", |
| 237 | free, (free * 100) / __LOG_BUF_LEN); |
| 238 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 240 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
| 241 | |
Namhyung Kim | 674dff6 | 2010-10-26 14:22:48 -0700 | [diff] [blame] | 242 | static int boot_delay; /* msecs delay after each printk during bootup */ |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 243 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 244 | |
| 245 | static int __init boot_delay_setup(char *str) |
| 246 | { |
| 247 | unsigned long lpj; |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 248 | |
| 249 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ |
| 250 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; |
| 251 | |
| 252 | get_option(&str, &boot_delay); |
| 253 | if (boot_delay > 10 * 1000) |
| 254 | boot_delay = 0; |
| 255 | |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 256 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
| 257 | "HZ: %d, loops_per_msec: %llu\n", |
| 258 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 259 | return 1; |
| 260 | } |
| 261 | __setup("boot_delay=", boot_delay_setup); |
| 262 | |
| 263 | static void boot_delay_msec(void) |
| 264 | { |
| 265 | unsigned long long k; |
| 266 | unsigned long timeout; |
| 267 | |
| 268 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) |
| 269 | return; |
| 270 | |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 271 | k = (unsigned long long)loops_per_msec * boot_delay; |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 272 | |
| 273 | timeout = jiffies + msecs_to_jiffies(boot_delay); |
| 274 | while (k) { |
| 275 | k--; |
| 276 | cpu_relax(); |
| 277 | /* |
| 278 | * use (volatile) jiffies to prevent |
| 279 | * compiler reduction; loop termination via jiffies |
| 280 | * is secondary and may or may not happen. |
| 281 | */ |
| 282 | if (time_after(jiffies, timeout)) |
| 283 | break; |
| 284 | touch_nmi_watchdog(); |
| 285 | } |
| 286 | } |
| 287 | #else |
| 288 | static inline void boot_delay_msec(void) |
| 289 | { |
| 290 | } |
| 291 | #endif |
| 292 | |
Dan Rosenberg | eaf06b2 | 2010-11-11 14:05:18 -0800 | [diff] [blame] | 293 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
| 294 | int dmesg_restrict = 1; |
| 295 | #else |
| 296 | int dmesg_restrict; |
| 297 | #endif |
| 298 | |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 299 | static int syslog_action_restricted(int type) |
| 300 | { |
| 301 | if (dmesg_restrict) |
| 302 | return 1; |
| 303 | /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ |
| 304 | return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; |
| 305 | } |
| 306 | |
| 307 | static int check_syslog_permissions(int type, bool from_file) |
| 308 | { |
| 309 | /* |
| 310 | * If this is from /proc/kmsg and we've already opened it, then we've |
| 311 | * already done the capabilities checks at open time. |
| 312 | */ |
| 313 | if (from_file && type != SYSLOG_ACTION_OPEN) |
| 314 | return 0; |
| 315 | |
| 316 | if (syslog_action_restricted(type)) { |
| 317 | if (capable(CAP_SYSLOG)) |
| 318 | return 0; |
| 319 | /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ |
| 320 | if (capable(CAP_SYS_ADMIN)) { |
Jonathan Nieder | f2c0d02 | 2011-08-08 06:22:43 +0200 | [diff] [blame] | 321 | printk_once(KERN_WARNING "%s (%d): " |
| 322 | "Attempt to access syslog with CAP_SYS_ADMIN " |
| 323 | "but no CAP_SYSLOG (deprecated).\n", |
| 324 | current->comm, task_pid_nr(current)); |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 325 | return 0; |
| 326 | } |
| 327 | return -EPERM; |
| 328 | } |
| 329 | return 0; |
| 330 | } |
| 331 | |
Kees Cook | 0023459 | 2010-02-03 15:36:43 -0800 | [diff] [blame] | 332 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 334 | unsigned i, j, limit, count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | int do_clear = 0; |
| 336 | char c; |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 337 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 339 | error = check_syslog_permissions(type, from_file); |
| 340 | if (error) |
| 341 | goto out; |
Eric Paris | 12b3052 | 2010-11-15 18:36:29 -0500 | [diff] [blame] | 342 | |
| 343 | error = security_syslog(type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | if (error) |
| 345 | return error; |
| 346 | |
| 347 | switch (type) { |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 348 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 350 | case SYSLOG_ACTION_OPEN: /* Open log */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 352 | case SYSLOG_ACTION_READ: /* Read from log */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | error = -EINVAL; |
| 354 | if (!buf || len < 0) |
| 355 | goto out; |
| 356 | error = 0; |
| 357 | if (!len) |
| 358 | goto out; |
| 359 | if (!access_ok(VERIFY_WRITE, buf, len)) { |
| 360 | error = -EFAULT; |
| 361 | goto out; |
| 362 | } |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 363 | error = wait_event_interruptible(log_wait, |
| 364 | (log_start - log_end)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | if (error) |
| 366 | goto out; |
| 367 | i = 0; |
| 368 | spin_lock_irq(&logbuf_lock); |
| 369 | while (!error && (log_start != log_end) && i < len) { |
| 370 | c = LOG_BUF(log_start); |
| 371 | log_start++; |
| 372 | spin_unlock_irq(&logbuf_lock); |
| 373 | error = __put_user(c,buf); |
| 374 | buf++; |
| 375 | i++; |
| 376 | cond_resched(); |
| 377 | spin_lock_irq(&logbuf_lock); |
| 378 | } |
| 379 | spin_unlock_irq(&logbuf_lock); |
| 380 | if (!error) |
| 381 | error = i; |
| 382 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 383 | /* Read/clear last kernel messages */ |
| 384 | case SYSLOG_ACTION_READ_CLEAR: |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 385 | do_clear = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | /* FALL THRU */ |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 387 | /* Read last kernel messages */ |
| 388 | case SYSLOG_ACTION_READ_ALL: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | error = -EINVAL; |
| 390 | if (!buf || len < 0) |
| 391 | goto out; |
| 392 | error = 0; |
| 393 | if (!len) |
| 394 | goto out; |
| 395 | if (!access_ok(VERIFY_WRITE, buf, len)) { |
| 396 | error = -EFAULT; |
| 397 | goto out; |
| 398 | } |
| 399 | count = len; |
| 400 | if (count > log_buf_len) |
| 401 | count = log_buf_len; |
| 402 | spin_lock_irq(&logbuf_lock); |
| 403 | if (count > logged_chars) |
| 404 | count = logged_chars; |
| 405 | if (do_clear) |
| 406 | logged_chars = 0; |
| 407 | limit = log_end; |
| 408 | /* |
| 409 | * __put_user() could sleep, and while we sleep |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 410 | * printk() could overwrite the messages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | * we try to copy to user space. Therefore |
| 412 | * the messages are copied in reverse. <manfreds> |
| 413 | */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 414 | for (i = 0; i < count && !error; i++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | j = limit-1-i; |
| 416 | if (j + log_buf_len < log_end) |
| 417 | break; |
| 418 | c = LOG_BUF(j); |
| 419 | spin_unlock_irq(&logbuf_lock); |
| 420 | error = __put_user(c,&buf[count-1-i]); |
| 421 | cond_resched(); |
| 422 | spin_lock_irq(&logbuf_lock); |
| 423 | } |
| 424 | spin_unlock_irq(&logbuf_lock); |
| 425 | if (error) |
| 426 | break; |
| 427 | error = i; |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 428 | if (i != count) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | int offset = count-error; |
| 430 | /* buffer overflow during copy, correct user buffer. */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 431 | for (i = 0; i < error; i++) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | if (__get_user(c,&buf[i+offset]) || |
| 433 | __put_user(c,&buf[i])) { |
| 434 | error = -EFAULT; |
| 435 | break; |
| 436 | } |
| 437 | cond_resched(); |
| 438 | } |
| 439 | } |
| 440 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 441 | /* Clear ring buffer */ |
| 442 | case SYSLOG_ACTION_CLEAR: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | logged_chars = 0; |
| 444 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 445 | /* Disable logging to console */ |
| 446 | case SYSLOG_ACTION_CONSOLE_OFF: |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 447 | if (saved_console_loglevel == -1) |
| 448 | saved_console_loglevel = console_loglevel; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | console_loglevel = minimum_console_loglevel; |
| 450 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 451 | /* Enable logging to console */ |
| 452 | case SYSLOG_ACTION_CONSOLE_ON: |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 453 | if (saved_console_loglevel != -1) { |
| 454 | console_loglevel = saved_console_loglevel; |
| 455 | saved_console_loglevel = -1; |
| 456 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 458 | /* Set level of messages printed to console */ |
| 459 | case SYSLOG_ACTION_CONSOLE_LEVEL: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | error = -EINVAL; |
| 461 | if (len < 1 || len > 8) |
| 462 | goto out; |
| 463 | if (len < minimum_console_loglevel) |
| 464 | len = minimum_console_loglevel; |
| 465 | console_loglevel = len; |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 466 | /* Implicitly re-enable logging to console */ |
| 467 | saved_console_loglevel = -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | error = 0; |
| 469 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 470 | /* Number of chars in the log buffer */ |
| 471 | case SYSLOG_ACTION_SIZE_UNREAD: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | error = log_end - log_start; |
| 473 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 474 | /* Size of the log buffer */ |
| 475 | case SYSLOG_ACTION_SIZE_BUFFER: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | error = log_buf_len; |
| 477 | break; |
| 478 | default: |
| 479 | error = -EINVAL; |
| 480 | break; |
| 481 | } |
| 482 | out: |
| 483 | return error; |
| 484 | } |
| 485 | |
Heiko Carstens | 1e7bfb2 | 2009-01-14 14:14:29 +0100 | [diff] [blame] | 486 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | { |
Kees Cook | 0023459 | 2010-02-03 15:36:43 -0800 | [diff] [blame] | 488 | return do_syslog(type, buf, len, SYSLOG_FROM_CALL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | } |
| 490 | |
Jason Wessel | 67fc4e0 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 491 | #ifdef CONFIG_KGDB_KDB |
| 492 | /* kdb dmesg command needs access to the syslog buffer. do_syslog() |
| 493 | * uses locks so it cannot be used during debugging. Just tell kdb |
| 494 | * where the start and end of the physical and logical logs are. This |
| 495 | * is equivalent to do_syslog(3). |
| 496 | */ |
| 497 | void kdb_syslog_data(char *syslog_data[4]) |
| 498 | { |
| 499 | syslog_data[0] = log_buf; |
| 500 | syslog_data[1] = log_buf + log_buf_len; |
| 501 | syslog_data[2] = log_buf + log_end - |
| 502 | (logged_chars < log_buf_len ? logged_chars : log_buf_len); |
| 503 | syslog_data[3] = log_buf + log_end; |
| 504 | } |
| 505 | #endif /* CONFIG_KGDB_KDB */ |
| 506 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | /* |
| 508 | * Call the console drivers on a range of log_buf |
| 509 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 510 | static void __call_console_drivers(unsigned start, unsigned end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | { |
| 512 | struct console *con; |
| 513 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 514 | for_each_console(con) { |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 515 | if (exclusive_console && con != exclusive_console) |
| 516 | continue; |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 517 | if ((con->flags & CON_ENABLED) && con->write && |
| 518 | (cpu_online(smp_processor_id()) || |
| 519 | (con->flags & CON_ANYTIME))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | con->write(con, &LOG_BUF(start), end - start); |
| 521 | } |
| 522 | } |
| 523 | |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 524 | static int __read_mostly ignore_loglevel; |
| 525 | |
Adrian Bunk | 99eea6a | 2006-12-22 01:07:00 -0800 | [diff] [blame] | 526 | static int __init ignore_loglevel_setup(char *str) |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 527 | { |
| 528 | ignore_loglevel = 1; |
| 529 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); |
| 530 | |
Ingo Molnar | c4772d9 | 2008-01-31 22:45:23 +0100 | [diff] [blame] | 531 | return 0; |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 532 | } |
| 533 | |
Ingo Molnar | c4772d9 | 2008-01-31 22:45:23 +0100 | [diff] [blame] | 534 | early_param("ignore_loglevel", ignore_loglevel_setup); |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 535 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | /* |
| 537 | * Write out chars from start to end - 1 inclusive |
| 538 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 539 | static void _call_console_drivers(unsigned start, |
| 540 | unsigned end, int msg_log_level) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | { |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 542 | if ((msg_log_level < console_loglevel || ignore_loglevel) && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | console_drivers && start != end) { |
| 544 | if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) { |
| 545 | /* wrapped write */ |
| 546 | __call_console_drivers(start & LOG_BUF_MASK, |
| 547 | log_buf_len); |
| 548 | __call_console_drivers(0, end & LOG_BUF_MASK); |
| 549 | } else { |
| 550 | __call_console_drivers(start, end); |
| 551 | } |
| 552 | } |
| 553 | } |
| 554 | |
| 555 | /* |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 556 | * Parse the syslog header <[0-9]*>. The decimal value represents 32bit, the |
| 557 | * lower 3 bit are the log level, the rest are the log facility. In case |
| 558 | * userspace passes usual userspace syslog messages to /dev/kmsg or |
| 559 | * /dev/ttyprintk, the log prefix might contain the facility. Printk needs |
| 560 | * to extract the correct log level for in-kernel processing, and not mangle |
| 561 | * the original value. |
| 562 | * |
| 563 | * If a prefix is found, the length of the prefix is returned. If 'level' is |
| 564 | * passed, it will be filled in with the log level without a possible facility |
| 565 | * value. If 'special' is passed, the special printk prefix chars are accepted |
| 566 | * and returned. If no valid header is found, 0 is returned and the passed |
| 567 | * variables are not touched. |
| 568 | */ |
| 569 | static size_t log_prefix(const char *p, unsigned int *level, char *special) |
| 570 | { |
| 571 | unsigned int lev = 0; |
| 572 | char sp = '\0'; |
| 573 | size_t len; |
| 574 | |
| 575 | if (p[0] != '<' || !p[1]) |
| 576 | return 0; |
| 577 | if (p[2] == '>') { |
| 578 | /* usual single digit level number or special char */ |
| 579 | switch (p[1]) { |
| 580 | case '0' ... '7': |
| 581 | lev = p[1] - '0'; |
| 582 | break; |
| 583 | case 'c': /* KERN_CONT */ |
| 584 | case 'd': /* KERN_DEFAULT */ |
| 585 | sp = p[1]; |
| 586 | break; |
| 587 | default: |
| 588 | return 0; |
| 589 | } |
| 590 | len = 3; |
| 591 | } else { |
| 592 | /* multi digit including the level and facility number */ |
| 593 | char *endp = NULL; |
| 594 | |
| 595 | if (p[1] < '0' && p[1] > '9') |
| 596 | return 0; |
| 597 | |
| 598 | lev = (simple_strtoul(&p[1], &endp, 10) & 7); |
| 599 | if (endp == NULL || endp[0] != '>') |
| 600 | return 0; |
| 601 | len = (endp + 1) - p; |
| 602 | } |
| 603 | |
| 604 | /* do not accept special char if not asked for */ |
| 605 | if (sp && !special) |
| 606 | return 0; |
| 607 | |
| 608 | if (special) { |
| 609 | *special = sp; |
| 610 | /* return special char, do not touch level */ |
| 611 | if (sp) |
| 612 | return len; |
| 613 | } |
| 614 | |
| 615 | if (level) |
| 616 | *level = lev; |
| 617 | return len; |
| 618 | } |
| 619 | |
| 620 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 621 | * Call the console drivers, asking them to write out |
| 622 | * log_buf[start] to log_buf[end - 1]. |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 623 | * The console_lock must be held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | */ |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 625 | static void call_console_drivers(unsigned start, unsigned end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 627 | unsigned cur_index, start_print; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | static int msg_level = -1; |
| 629 | |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 630 | BUG_ON(((int)(start - end)) > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | |
| 632 | cur_index = start; |
| 633 | start_print = start; |
| 634 | while (cur_index != end) { |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 635 | if (msg_level < 0 && ((end - cur_index) > 2)) { |
| 636 | /* strip log prefix */ |
| 637 | cur_index += log_prefix(&LOG_BUF(cur_index), &msg_level, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 638 | start_print = cur_index; |
| 639 | } |
| 640 | while (cur_index != end) { |
| 641 | char c = LOG_BUF(cur_index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 642 | |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 643 | cur_index++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | if (c == '\n') { |
| 645 | if (msg_level < 0) { |
| 646 | /* |
| 647 | * printk() has already given us loglevel tags in |
| 648 | * the buffer. This code is here in case the |
| 649 | * log buffer has wrapped right round and scribbled |
| 650 | * on those tags |
| 651 | */ |
| 652 | msg_level = default_message_loglevel; |
| 653 | } |
| 654 | _call_console_drivers(start_print, cur_index, msg_level); |
| 655 | msg_level = -1; |
| 656 | start_print = cur_index; |
| 657 | break; |
| 658 | } |
| 659 | } |
| 660 | } |
| 661 | _call_console_drivers(start_print, end, msg_level); |
| 662 | } |
| 663 | |
| 664 | static void emit_log_char(char c) |
| 665 | { |
| 666 | LOG_BUF(log_end) = c; |
| 667 | log_end++; |
| 668 | if (log_end - log_start > log_buf_len) |
| 669 | log_start = log_end - log_buf_len; |
| 670 | if (log_end - con_start > log_buf_len) |
| 671 | con_start = log_end - log_buf_len; |
| 672 | if (logged_chars < log_buf_len) |
| 673 | logged_chars++; |
| 674 | } |
| 675 | |
| 676 | /* |
| 677 | * Zap console related locks when oopsing. Only zap at most once |
| 678 | * every 10 seconds, to leave time for slow consoles to print a |
| 679 | * full oops. |
| 680 | */ |
| 681 | static void zap_locks(void) |
| 682 | { |
| 683 | static unsigned long oops_timestamp; |
| 684 | |
| 685 | if (time_after_eq(jiffies, oops_timestamp) && |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 686 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | return; |
| 688 | |
| 689 | oops_timestamp = jiffies; |
| 690 | |
| 691 | /* If a crash is occurring, make sure we can't deadlock */ |
| 692 | spin_lock_init(&logbuf_lock); |
| 693 | /* And make sure that we print immediately */ |
Thomas Gleixner | 5b8c4f2 | 2010-09-07 14:33:43 +0000 | [diff] [blame] | 694 | sema_init(&console_sem, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | } |
| 696 | |
| 697 | #if defined(CONFIG_PRINTK_TIME) |
| 698 | static int printk_time = 1; |
| 699 | #else |
| 700 | static int printk_time = 0; |
| 701 | #endif |
Randy Dunlap | e84845c | 2007-07-15 23:40:25 -0700 | [diff] [blame] | 702 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 704 | /* Check if we have any console registered that can be called early in boot. */ |
| 705 | static int have_callable_console(void) |
| 706 | { |
| 707 | struct console *con; |
| 708 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 709 | for_each_console(con) |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 710 | if (con->flags & CON_ANYTIME) |
| 711 | return 1; |
| 712 | |
| 713 | return 0; |
| 714 | } |
| 715 | |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 716 | /** |
| 717 | * printk - print a kernel message |
| 718 | * @fmt: format string |
| 719 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 720 | * 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] | 721 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 722 | * We try to grab the console_lock. If we succeed, it's easy - we log the output and |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | * call the console drivers. If we fail to get the semaphore we place the output |
| 724 | * into the log buffer and return. The current holder of the console_sem will |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 725 | * notice the new output in console_unlock(); and will send it to the |
| 726 | * consoles before releasing the lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 727 | * |
| 728 | * One effect of this deferred printing is that code which calls printk() and |
| 729 | * then changes console_loglevel may break. This is because console_loglevel |
| 730 | * is inspected when the actual printing occurs. |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 731 | * |
| 732 | * See also: |
| 733 | * printf(3) |
Andi Kleen | 20036fd | 2008-10-15 22:02:02 -0700 | [diff] [blame] | 734 | * |
| 735 | * See the vsnprintf() documentation for format string extensions over C99. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | */ |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 737 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | asmlinkage int printk(const char *fmt, ...) |
| 739 | { |
| 740 | va_list args; |
| 741 | int r; |
| 742 | |
Jason Wessel | d37d39a | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 743 | #ifdef CONFIG_KGDB_KDB |
| 744 | if (unlikely(kdb_trap_printk)) { |
| 745 | va_start(args, fmt); |
| 746 | r = vkdb_printf(fmt, args); |
| 747 | va_end(args); |
| 748 | return r; |
| 749 | } |
| 750 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | va_start(args, fmt); |
| 752 | r = vprintk(fmt, args); |
| 753 | va_end(args); |
| 754 | |
| 755 | return r; |
| 756 | } |
| 757 | |
David Howells | fe21773 | 2005-09-06 15:16:34 -0700 | [diff] [blame] | 758 | /* cpu currently holding logbuf_lock */ |
| 759 | static volatile unsigned int printk_cpu = UINT_MAX; |
| 760 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 761 | /* |
| 762 | * Can we actually use the console at this time on this cpu? |
| 763 | * |
| 764 | * Console drivers may assume that per-cpu resources have |
| 765 | * been allocated. So unless they're explicitly marked as |
| 766 | * being able to cope (CON_ANYTIME) don't call them until |
| 767 | * this CPU is officially up. |
| 768 | */ |
| 769 | static inline int can_use_console(unsigned int cpu) |
| 770 | { |
| 771 | return cpu_online(cpu) || have_callable_console(); |
| 772 | } |
| 773 | |
| 774 | /* |
| 775 | * Try to get console ownership to actually show the kernel |
| 776 | * messages from a 'printk'. Return true (and with the |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 777 | * console_lock held, and 'console_locked' set) if it |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 778 | * is successful, false otherwise. |
| 779 | * |
| 780 | * This gets called with the 'logbuf_lock' spinlock held and |
| 781 | * interrupts disabled. It should return with 'lockbuf_lock' |
| 782 | * released but interrupts still disabled. |
| 783 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 784 | static int console_trylock_for_printk(unsigned int cpu) |
Namhyung Kim | 8155c02 | 2010-10-26 14:22:47 -0700 | [diff] [blame] | 785 | __releases(&logbuf_lock) |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 786 | { |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 787 | int retval = 0, wake = 0; |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 788 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 789 | if (console_trylock()) { |
Linus Torvalds | 093a07e | 2008-04-15 13:09:54 -0700 | [diff] [blame] | 790 | retval = 1; |
| 791 | |
| 792 | /* |
| 793 | * If we can't use the console, we need to release |
| 794 | * the console semaphore by hand to avoid flushing |
| 795 | * the buffer. We need to hold the console semaphore |
| 796 | * in order to do this test safely. |
| 797 | */ |
| 798 | if (!can_use_console(cpu)) { |
| 799 | console_locked = 0; |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 800 | wake = 1; |
Linus Torvalds | 093a07e | 2008-04-15 13:09:54 -0700 | [diff] [blame] | 801 | retval = 0; |
| 802 | } |
| 803 | } |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 804 | printk_cpu = UINT_MAX; |
| 805 | spin_unlock(&logbuf_lock); |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 806 | if (wake) |
| 807 | up(&console_sem); |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 808 | return retval; |
| 809 | } |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 810 | static const char recursion_bug_msg [] = |
| 811 | KERN_CRIT "BUG: recent printk recursion!\n"; |
| 812 | static int recursion_bug; |
Jiri Kosina | edb123e | 2008-12-04 12:39:49 +0100 | [diff] [blame] | 813 | static int new_text_line = 1; |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 814 | static char printk_buf[1024]; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 815 | |
Dave Young | af91322 | 2009-09-22 16:43:33 -0700 | [diff] [blame] | 816 | int printk_delay_msec __read_mostly; |
| 817 | |
| 818 | static inline void printk_delay(void) |
| 819 | { |
| 820 | if (unlikely(printk_delay_msec)) { |
| 821 | int m = printk_delay_msec; |
| 822 | |
| 823 | while (m--) { |
| 824 | mdelay(1); |
| 825 | touch_nmi_watchdog(); |
| 826 | } |
| 827 | } |
| 828 | } |
| 829 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | asmlinkage int vprintk(const char *fmt, va_list args) |
| 831 | { |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 832 | int printed_len = 0; |
Nick Andrew | 0915930 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 833 | int current_log_level = default_message_loglevel; |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 834 | unsigned long flags; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 835 | int this_cpu; |
| 836 | char *p; |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 837 | size_t plen; |
| 838 | char special; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 840 | boot_delay_msec(); |
Dave Young | af91322 | 2009-09-22 16:43:33 -0700 | [diff] [blame] | 841 | printk_delay(); |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 842 | |
David Howells | fe21773 | 2005-09-06 15:16:34 -0700 | [diff] [blame] | 843 | preempt_disable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | /* This stops the holder of console_sem just where we want him */ |
Mathieu Desnoyers | 1efc5da | 2007-02-10 01:46:29 -0800 | [diff] [blame] | 845 | raw_local_irq_save(flags); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 846 | this_cpu = smp_processor_id(); |
| 847 | |
| 848 | /* |
| 849 | * Ouch, printk recursed into itself! |
| 850 | */ |
| 851 | if (unlikely(printk_cpu == this_cpu)) { |
| 852 | /* |
| 853 | * If a crash is occurring during printk() on this CPU, |
| 854 | * then try to get the crash message out but make sure |
| 855 | * we can't deadlock. Otherwise just return to avoid the |
| 856 | * recursion and return - but flag the recursion so that |
| 857 | * it can be printed at the next appropriate moment: |
| 858 | */ |
| 859 | if (!oops_in_progress) { |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 860 | recursion_bug = 1; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 861 | goto out_restore_irqs; |
| 862 | } |
| 863 | zap_locks(); |
| 864 | } |
| 865 | |
Ingo Molnar | a0f1ccf | 2006-07-03 00:24:58 -0700 | [diff] [blame] | 866 | lockdep_off(); |
| 867 | spin_lock(&logbuf_lock); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 868 | printk_cpu = this_cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 870 | if (recursion_bug) { |
| 871 | recursion_bug = 0; |
| 872 | strcpy(printk_buf, recursion_bug_msg); |
Hiroshi Shimamoto | 26cc271 | 2008-12-19 10:23:03 -0800 | [diff] [blame] | 873 | printed_len = strlen(recursion_bug_msg); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 874 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | /* Emit the output into the temporary buffer */ |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 876 | printed_len += vscnprintf(printk_buf + printed_len, |
Tejun Heo | cf3680b | 2008-02-14 10:32:07 +0900 | [diff] [blame] | 877 | sizeof(printk_buf) - printed_len, fmt, args); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 878 | |
Linus Torvalds | 5fd29d6 | 2009-06-16 10:57:02 -0700 | [diff] [blame] | 879 | p = printk_buf; |
| 880 | |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 881 | /* Read log level and handle special printk prefix */ |
| 882 | plen = log_prefix(p, ¤t_log_level, &special); |
| 883 | if (plen) { |
| 884 | p += plen; |
| 885 | |
| 886 | switch (special) { |
| 887 | case 'c': /* Strip <c> KERN_CONT, continue line */ |
| 888 | plen = 0; |
| 889 | break; |
| 890 | case 'd': /* Strip <d> KERN_DEFAULT, start new line */ |
| 891 | plen = 0; |
| 892 | default: |
| 893 | if (!new_text_line) { |
| 894 | emit_log_char('\n'); |
| 895 | new_text_line = 1; |
Linus Torvalds | 5fd29d6 | 2009-06-16 10:57:02 -0700 | [diff] [blame] | 896 | } |
| 897 | } |
| 898 | } |
| 899 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 900 | /* |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 901 | * Copy the output into log_buf. If the caller didn't provide |
| 902 | * the appropriate log prefix, we insert them here |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | */ |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 904 | for (; *p; p++) { |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 905 | if (new_text_line) { |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 906 | new_text_line = 0; |
| 907 | |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 908 | if (plen) { |
| 909 | /* Copy original log prefix */ |
| 910 | int i; |
| 911 | |
| 912 | for (i = 0; i < plen; i++) |
| 913 | emit_log_char(printk_buf[i]); |
| 914 | printed_len += plen; |
| 915 | } else { |
| 916 | /* Add log prefix */ |
| 917 | emit_log_char('<'); |
| 918 | emit_log_char(current_log_level + '0'); |
| 919 | emit_log_char('>'); |
| 920 | printed_len += 3; |
| 921 | } |
| 922 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 923 | if (printk_time) { |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 924 | /* Add the current time stamp */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | char tbuf[50], *tp; |
| 926 | unsigned tlen; |
| 927 | unsigned long long t; |
| 928 | unsigned long nanosec_rem; |
| 929 | |
Ingo Molnar | 326e96b | 2008-01-27 08:03:54 +0100 | [diff] [blame] | 930 | t = cpu_clock(printk_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 931 | nanosec_rem = do_div(t, 1000000000); |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 932 | tlen = sprintf(tbuf, "[%5lu.%06lu] ", |
| 933 | (unsigned long) t, |
| 934 | nanosec_rem / 1000); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | |
| 936 | for (tp = tbuf; tp < tbuf + tlen; tp++) |
| 937 | emit_log_char(*tp); |
Guillaume Chazarain | 025510c | 2006-01-08 01:02:41 -0800 | [diff] [blame] | 938 | printed_len += tlen; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | } |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 940 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 941 | if (!*p) |
| 942 | break; |
| 943 | } |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 944 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | emit_log_char(*p); |
| 946 | if (*p == '\n') |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 947 | new_text_line = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 948 | } |
| 949 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 950 | /* |
| 951 | * Try to acquire and then immediately release the |
| 952 | * console semaphore. The release will do all the |
| 953 | * actual magic (print out buffers, wake up klogd, |
| 954 | * etc). |
| 955 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 956 | * The console_trylock_for_printk() function |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 957 | * will release 'logbuf_lock' regardless of whether it |
| 958 | * actually gets the semaphore or not. |
| 959 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 960 | if (console_trylock_for_printk(this_cpu)) |
| 961 | console_unlock(); |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 962 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 963 | lockdep_on(); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 964 | out_restore_irqs: |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 965 | raw_local_irq_restore(flags); |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 966 | |
David Howells | fe21773 | 2005-09-06 15:16:34 -0700 | [diff] [blame] | 967 | preempt_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 968 | return printed_len; |
| 969 | } |
| 970 | EXPORT_SYMBOL(printk); |
| 971 | EXPORT_SYMBOL(vprintk); |
| 972 | |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 973 | #else |
| 974 | |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 975 | static void call_console_drivers(unsigned start, unsigned end) |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 976 | { |
| 977 | } |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 978 | |
| 979 | #endif |
| 980 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 981 | static int __add_preferred_console(char *name, int idx, char *options, |
| 982 | char *brl_options) |
| 983 | { |
| 984 | struct console_cmdline *c; |
| 985 | int i; |
| 986 | |
| 987 | /* |
| 988 | * See if this tty is not yet registered, and |
| 989 | * if we have a slot free. |
| 990 | */ |
| 991 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| 992 | if (strcmp(console_cmdline[i].name, name) == 0 && |
| 993 | console_cmdline[i].index == idx) { |
| 994 | if (!brl_options) |
| 995 | selected_console = i; |
| 996 | return 0; |
| 997 | } |
| 998 | if (i == MAX_CMDLINECONSOLES) |
| 999 | return -E2BIG; |
| 1000 | if (!brl_options) |
| 1001 | selected_console = i; |
| 1002 | c = &console_cmdline[i]; |
| 1003 | strlcpy(c->name, name, sizeof(c->name)); |
| 1004 | c->options = options; |
| 1005 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1006 | c->brl_options = brl_options; |
| 1007 | #endif |
| 1008 | c->index = idx; |
| 1009 | return 0; |
| 1010 | } |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1011 | /* |
| 1012 | * Set up a list of consoles. Called from init/main.c |
| 1013 | */ |
| 1014 | static int __init console_setup(char *str) |
| 1015 | { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1016 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1017 | char *s, *options, *brl_options = NULL; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1018 | int idx; |
| 1019 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1020 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1021 | if (!memcmp(str, "brl,", 4)) { |
| 1022 | brl_options = ""; |
| 1023 | str += 4; |
| 1024 | } else if (!memcmp(str, "brl=", 4)) { |
| 1025 | brl_options = str + 4; |
| 1026 | str = strchr(brl_options, ','); |
| 1027 | if (!str) { |
| 1028 | printk(KERN_ERR "need port name after brl=\n"); |
| 1029 | return 1; |
| 1030 | } |
| 1031 | *(str++) = 0; |
| 1032 | } |
| 1033 | #endif |
| 1034 | |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1035 | /* |
| 1036 | * Decode str into name, index, options. |
| 1037 | */ |
| 1038 | if (str[0] >= '0' && str[0] <= '9') { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1039 | strcpy(buf, "ttyS"); |
| 1040 | strncpy(buf + 4, str, sizeof(buf) - 5); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1041 | } else { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1042 | strncpy(buf, str, sizeof(buf) - 1); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1043 | } |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1044 | buf[sizeof(buf) - 1] = 0; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1045 | if ((options = strchr(str, ',')) != NULL) |
| 1046 | *(options++) = 0; |
| 1047 | #ifdef __sparc__ |
| 1048 | if (!strcmp(str, "ttya")) |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1049 | strcpy(buf, "ttyS0"); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1050 | if (!strcmp(str, "ttyb")) |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1051 | strcpy(buf, "ttyS1"); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1052 | #endif |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1053 | for (s = buf; *s; s++) |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1054 | if ((*s >= '0' && *s <= '9') || *s == ',') |
| 1055 | break; |
| 1056 | idx = simple_strtoul(s, NULL, 10); |
| 1057 | *s = 0; |
| 1058 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1059 | __add_preferred_console(buf, idx, options, brl_options); |
Markus Armbruster | 9e124fe | 2008-05-26 23:31:07 +0100 | [diff] [blame] | 1060 | console_set_on_cmdline = 1; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1061 | return 1; |
| 1062 | } |
| 1063 | __setup("console=", console_setup); |
| 1064 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | /** |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1066 | * add_preferred_console - add a device to the list of preferred consoles. |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 1067 | * @name: device name |
| 1068 | * @idx: device index |
| 1069 | * @options: options for this console |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1070 | * |
| 1071 | * The last preferred console added will be used for kernel messages |
| 1072 | * and stdin/out/err for init. Normally this is used by console_setup |
| 1073 | * above to handle user-supplied console arguments; however it can also |
| 1074 | * be used by arch-specific code either to override the user or more |
| 1075 | * commonly to provide a default console (ie from PROM variables) when |
| 1076 | * the user has not supplied one. |
| 1077 | */ |
David S. Miller | fb445ee | 2007-12-29 01:19:49 -0800 | [diff] [blame] | 1078 | int add_preferred_console(char *name, int idx, char *options) |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1079 | { |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1080 | return __add_preferred_console(name, idx, options, NULL); |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1081 | } |
| 1082 | |
Daniel Ritz | b6b1d87 | 2007-08-03 16:07:43 +0200 | [diff] [blame] | 1083 | 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] | 1084 | { |
| 1085 | struct console_cmdline *c; |
| 1086 | int i; |
| 1087 | |
| 1088 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| 1089 | if (strcmp(console_cmdline[i].name, name) == 0 && |
| 1090 | console_cmdline[i].index == idx) { |
| 1091 | c = &console_cmdline[i]; |
Markus Armbruster | f735295 | 2008-04-30 00:54:52 -0700 | [diff] [blame] | 1092 | strlcpy(c->name, name_new, sizeof(c->name)); |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 1093 | c->name[sizeof(c->name) - 1] = 0; |
| 1094 | c->options = options; |
| 1095 | c->index = idx_new; |
| 1096 | return i; |
| 1097 | } |
| 1098 | /* not found */ |
| 1099 | return -1; |
| 1100 | } |
| 1101 | |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1102 | int console_suspend_enabled = 1; |
| 1103 | EXPORT_SYMBOL(console_suspend_enabled); |
| 1104 | |
| 1105 | static int __init console_suspend_disable(char *str) |
| 1106 | { |
| 1107 | console_suspend_enabled = 0; |
| 1108 | return 1; |
| 1109 | } |
| 1110 | __setup("no_console_suspend", console_suspend_disable); |
| 1111 | |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1112 | /** |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1113 | * suspend_console - suspend the console subsystem |
| 1114 | * |
| 1115 | * This disables printk() while we go into suspend states |
| 1116 | */ |
| 1117 | void suspend_console(void) |
| 1118 | { |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1119 | if (!console_suspend_enabled) |
| 1120 | return; |
Pavel Machek | 0d63081 | 2008-07-23 21:28:32 -0700 | [diff] [blame] | 1121 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1122 | console_lock(); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1123 | console_suspended = 1; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1124 | up(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1125 | } |
| 1126 | |
| 1127 | void resume_console(void) |
| 1128 | { |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1129 | if (!console_suspend_enabled) |
| 1130 | return; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1131 | down(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1132 | console_suspended = 0; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1133 | console_unlock(); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1134 | } |
| 1135 | |
| 1136 | /** |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1137 | * console_cpu_notify - print deferred console messages after CPU hotplug |
| 1138 | * @self: notifier struct |
| 1139 | * @action: CPU hotplug event |
| 1140 | * @hcpu: unused |
| 1141 | * |
| 1142 | * If printk() is called from a CPU that is not online yet, the messages |
| 1143 | * will be spooled but will not show up on the console. This function is |
| 1144 | * called when a new CPU comes online (or fails to come up), and ensures |
| 1145 | * that any such output gets printed. |
| 1146 | */ |
| 1147 | static int __cpuinit console_cpu_notify(struct notifier_block *self, |
| 1148 | unsigned long action, void *hcpu) |
| 1149 | { |
| 1150 | switch (action) { |
| 1151 | case CPU_ONLINE: |
| 1152 | case CPU_DEAD: |
| 1153 | case CPU_DYING: |
| 1154 | case CPU_DOWN_FAILED: |
| 1155 | case CPU_UP_CANCELED: |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1156 | console_lock(); |
| 1157 | console_unlock(); |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1158 | } |
| 1159 | return NOTIFY_OK; |
| 1160 | } |
| 1161 | |
| 1162 | /** |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1163 | * console_lock - lock the console system for exclusive use. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1165 | * Acquires a lock which guarantees that the caller has |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | * exclusive access to the console system and the console_drivers list. |
| 1167 | * |
| 1168 | * Can sleep, returns nothing. |
| 1169 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1170 | void console_lock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1171 | { |
Eric Sesterhenn | 8abd8e2 | 2006-04-01 01:21:17 +0200 | [diff] [blame] | 1172 | BUG_ON(in_interrupt()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1173 | down(&console_sem); |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1174 | if (console_suspended) |
| 1175 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1176 | console_locked = 1; |
| 1177 | console_may_schedule = 1; |
| 1178 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1179 | EXPORT_SYMBOL(console_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1180 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1181 | /** |
| 1182 | * console_trylock - try to lock the console system for exclusive use. |
| 1183 | * |
| 1184 | * Tried to acquire a lock which guarantees that the caller has |
| 1185 | * exclusive access to the console system and the console_drivers list. |
| 1186 | * |
| 1187 | * returns 1 on success, and 0 on failure to acquire the lock. |
| 1188 | */ |
| 1189 | int console_trylock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1190 | { |
| 1191 | if (down_trylock(&console_sem)) |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1192 | return 0; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1193 | if (console_suspended) { |
| 1194 | up(&console_sem); |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1195 | return 0; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1196 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1197 | console_locked = 1; |
| 1198 | console_may_schedule = 0; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1199 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1201 | EXPORT_SYMBOL(console_trylock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1202 | |
| 1203 | int is_console_locked(void) |
| 1204 | { |
| 1205 | return console_locked; |
| 1206 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1207 | |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1208 | static DEFINE_PER_CPU(int, printk_pending); |
| 1209 | |
| 1210 | void printk_tick(void) |
| 1211 | { |
Eric Dumazet | 40dc11f | 2010-11-26 17:22:16 +0100 | [diff] [blame] | 1212 | if (__this_cpu_read(printk_pending)) { |
| 1213 | __this_cpu_write(printk_pending, 0); |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1214 | wake_up_interruptible(&log_wait); |
| 1215 | } |
| 1216 | } |
| 1217 | |
| 1218 | int printk_needs_cpu(int cpu) |
| 1219 | { |
Eric Dumazet | 40dc11f | 2010-11-26 17:22:16 +0100 | [diff] [blame] | 1220 | if (cpu_is_offline(cpu)) |
Heiko Carstens | 61ab2544 | 2010-11-26 13:00:59 +0100 | [diff] [blame] | 1221 | printk_tick(); |
Eric Dumazet | 40dc11f | 2010-11-26 17:22:16 +0100 | [diff] [blame] | 1222 | return __this_cpu_read(printk_pending); |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1223 | } |
| 1224 | |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1225 | void wake_up_klogd(void) |
| 1226 | { |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1227 | if (waitqueue_active(&log_wait)) |
Heiko Carstens | 49f4138 | 2010-11-26 13:42:47 +0100 | [diff] [blame] | 1228 | this_cpu_write(printk_pending, 1); |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1229 | } |
| 1230 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1231 | /** |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1232 | * console_unlock - unlock the console system |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1234 | * Releases the console_lock which the caller holds on the console system |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1235 | * and the console driver list. |
| 1236 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1237 | * While the console_lock was held, console output may have been buffered |
| 1238 | * by printk(). If this is the case, console_unlock(); emits |
| 1239 | * the output prior to releasing the lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1240 | * |
| 1241 | * If there is output waiting for klogd, we wake it up. |
| 1242 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1243 | * console_unlock(); may be called from any context. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1244 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1245 | void console_unlock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1246 | { |
| 1247 | unsigned long flags; |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 1248 | unsigned _con_start, _log_end; |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 1249 | unsigned wake_klogd = 0, retry = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1251 | if (console_suspended) { |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1252 | up(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1253 | return; |
| 1254 | } |
Antonino A. Daplas | 78944e5 | 2006-08-05 12:14:16 -0700 | [diff] [blame] | 1255 | |
| 1256 | console_may_schedule = 0; |
| 1257 | |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 1258 | again: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1259 | for ( ; ; ) { |
| 1260 | spin_lock_irqsave(&logbuf_lock, flags); |
| 1261 | wake_klogd |= log_start - log_end; |
| 1262 | if (con_start == log_end) |
| 1263 | break; /* Nothing to print */ |
| 1264 | _con_start = con_start; |
| 1265 | _log_end = log_end; |
| 1266 | con_start = log_end; /* Flush */ |
| 1267 | spin_unlock(&logbuf_lock); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1268 | stop_critical_timings(); /* don't trace print latency */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | call_console_drivers(_con_start, _log_end); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1270 | start_critical_timings(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1271 | local_irq_restore(flags); |
| 1272 | } |
| 1273 | console_locked = 0; |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 1274 | |
| 1275 | /* Release the exclusive_console once it is used */ |
| 1276 | if (unlikely(exclusive_console)) |
| 1277 | exclusive_console = NULL; |
| 1278 | |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 1279 | spin_unlock(&logbuf_lock); |
| 1280 | |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 1281 | up(&console_sem); |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 1282 | |
| 1283 | /* |
| 1284 | * Someone could have filled up the buffer again, so re-check if there's |
| 1285 | * something to flush. In case we cannot trylock the console_sem again, |
| 1286 | * there's a new owner and the console_unlock() from them will do the |
| 1287 | * flush, no worries. |
| 1288 | */ |
| 1289 | spin_lock(&logbuf_lock); |
| 1290 | if (con_start != log_end) |
| 1291 | retry = 1; |
| 1292 | spin_unlock_irqrestore(&logbuf_lock, flags); |
| 1293 | if (retry && console_trylock()) |
| 1294 | goto again; |
| 1295 | |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1296 | if (wake_klogd) |
| 1297 | wake_up_klogd(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1298 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1299 | EXPORT_SYMBOL(console_unlock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1300 | |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 1301 | /** |
| 1302 | * console_conditional_schedule - yield the CPU if required |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | * |
| 1304 | * If the console code is currently allowed to sleep, and |
| 1305 | * if this CPU should yield the CPU to another task, do |
| 1306 | * so here. |
| 1307 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1308 | * Must be called within console_lock();. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1309 | */ |
| 1310 | void __sched console_conditional_schedule(void) |
| 1311 | { |
| 1312 | if (console_may_schedule) |
| 1313 | cond_resched(); |
| 1314 | } |
| 1315 | EXPORT_SYMBOL(console_conditional_schedule); |
| 1316 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1317 | void console_unblank(void) |
| 1318 | { |
| 1319 | struct console *c; |
| 1320 | |
| 1321 | /* |
| 1322 | * console_unblank can no longer be called in interrupt context unless |
| 1323 | * oops_in_progress is set to 1.. |
| 1324 | */ |
| 1325 | if (oops_in_progress) { |
| 1326 | if (down_trylock(&console_sem) != 0) |
| 1327 | return; |
| 1328 | } else |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1329 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1330 | |
| 1331 | console_locked = 1; |
| 1332 | console_may_schedule = 0; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1333 | for_each_console(c) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1334 | if ((c->flags & CON_ENABLED) && c->unblank) |
| 1335 | c->unblank(); |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1336 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1337 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1338 | |
| 1339 | /* |
| 1340 | * Return the console tty driver structure and its associated index |
| 1341 | */ |
| 1342 | struct tty_driver *console_device(int *index) |
| 1343 | { |
| 1344 | struct console *c; |
| 1345 | struct tty_driver *driver = NULL; |
| 1346 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1347 | console_lock(); |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1348 | for_each_console(c) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1349 | if (!c->device) |
| 1350 | continue; |
| 1351 | driver = c->device(c, index); |
| 1352 | if (driver) |
| 1353 | break; |
| 1354 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1355 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1356 | return driver; |
| 1357 | } |
| 1358 | |
| 1359 | /* |
| 1360 | * Prevent further output on the passed console device so that (for example) |
| 1361 | * serial drivers can disable console output before suspending a port, and can |
| 1362 | * re-enable output afterwards. |
| 1363 | */ |
| 1364 | void console_stop(struct console *console) |
| 1365 | { |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1366 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1367 | console->flags &= ~CON_ENABLED; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1368 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1369 | } |
| 1370 | EXPORT_SYMBOL(console_stop); |
| 1371 | |
| 1372 | void console_start(struct console *console) |
| 1373 | { |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1374 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1375 | console->flags |= CON_ENABLED; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1376 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1377 | } |
| 1378 | EXPORT_SYMBOL(console_start); |
| 1379 | |
Fabio M. Di Nitto | 7bf6939 | 2011-03-22 16:34:20 -0700 | [diff] [blame] | 1380 | static int __read_mostly keep_bootcon; |
| 1381 | |
| 1382 | static int __init keep_bootcon_setup(char *str) |
| 1383 | { |
| 1384 | keep_bootcon = 1; |
| 1385 | printk(KERN_INFO "debug: skip boot console de-registration.\n"); |
| 1386 | |
| 1387 | return 0; |
| 1388 | } |
| 1389 | |
| 1390 | early_param("keep_bootcon", keep_bootcon_setup); |
| 1391 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1392 | /* |
| 1393 | * The console driver calls this routine during kernel initialization |
| 1394 | * to register the console printing procedure with printk() and to |
| 1395 | * print any messages that were printed by the kernel before the |
| 1396 | * console driver was initialized. |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1397 | * |
| 1398 | * This can happen pretty early during the boot process (because of |
| 1399 | * early_printk) - sometimes before setup_arch() completes - be careful |
| 1400 | * of what kernel features are used - they may not be initialised yet. |
| 1401 | * |
| 1402 | * There are two types of consoles - bootconsoles (early_printk) and |
| 1403 | * "real" consoles (everything which is not a bootconsole) which are |
| 1404 | * handled differently. |
| 1405 | * - Any number of bootconsoles can be registered at any time. |
| 1406 | * - As soon as a "real" console is registered, all bootconsoles |
| 1407 | * will be unregistered automatically. |
| 1408 | * - Once a "real" console is registered, any attempt to register a |
| 1409 | * bootconsoles will be rejected |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1410 | */ |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1411 | void register_console(struct console *newcon) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1412 | { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1413 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1414 | unsigned long flags; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1415 | struct console *bcon = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1416 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1417 | /* |
| 1418 | * before we register a new CON_BOOT console, make sure we don't |
| 1419 | * already have a valid console |
| 1420 | */ |
| 1421 | if (console_drivers && newcon->flags & CON_BOOT) { |
| 1422 | /* find the last or real console */ |
| 1423 | for_each_console(bcon) { |
| 1424 | if (!(bcon->flags & CON_BOOT)) { |
| 1425 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", |
| 1426 | newcon->name, newcon->index); |
| 1427 | return; |
| 1428 | } |
| 1429 | } |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 1430 | } |
| 1431 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1432 | if (console_drivers && console_drivers->flags & CON_BOOT) |
| 1433 | bcon = console_drivers; |
| 1434 | |
| 1435 | if (preferred_console < 0 || bcon || !console_drivers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1436 | preferred_console = selected_console; |
| 1437 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1438 | if (newcon->early_setup) |
| 1439 | newcon->early_setup(); |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 1440 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1441 | /* |
| 1442 | * See if we want to use this console driver. If we |
| 1443 | * didn't select a console we take the first one |
| 1444 | * that registers here. |
| 1445 | */ |
| 1446 | if (preferred_console < 0) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1447 | if (newcon->index < 0) |
| 1448 | newcon->index = 0; |
| 1449 | if (newcon->setup == NULL || |
| 1450 | newcon->setup(newcon, NULL) == 0) { |
| 1451 | newcon->flags |= CON_ENABLED; |
| 1452 | if (newcon->device) { |
| 1453 | newcon->flags |= CON_CONSDEV; |
Jan Kiszka | cd3a1b8 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1454 | preferred_console = 0; |
| 1455 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1456 | } |
| 1457 | } |
| 1458 | |
| 1459 | /* |
| 1460 | * See if this console matches one we selected on |
| 1461 | * the command line. |
| 1462 | */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1463 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
| 1464 | i++) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1465 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1466 | continue; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1467 | if (newcon->index >= 0 && |
| 1468 | newcon->index != console_cmdline[i].index) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1469 | continue; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1470 | if (newcon->index < 0) |
| 1471 | newcon->index = console_cmdline[i].index; |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1472 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1473 | if (console_cmdline[i].brl_options) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1474 | newcon->flags |= CON_BRL; |
| 1475 | braille_register_console(newcon, |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1476 | console_cmdline[i].index, |
| 1477 | console_cmdline[i].options, |
| 1478 | console_cmdline[i].brl_options); |
| 1479 | return; |
| 1480 | } |
| 1481 | #endif |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1482 | if (newcon->setup && |
| 1483 | newcon->setup(newcon, console_cmdline[i].options) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1484 | break; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1485 | newcon->flags |= CON_ENABLED; |
| 1486 | newcon->index = console_cmdline[i].index; |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1487 | if (i == selected_console) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1488 | newcon->flags |= CON_CONSDEV; |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1489 | preferred_console = selected_console; |
| 1490 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1491 | break; |
| 1492 | } |
| 1493 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1494 | if (!(newcon->flags & CON_ENABLED)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1495 | return; |
| 1496 | |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 1497 | /* |
| 1498 | * If we have a bootconsole, and are switching to a real console, |
| 1499 | * don't print everything out again, since when the boot console, and |
| 1500 | * the real console are the same physical device, it's annoying to |
| 1501 | * see the beginning boot messages twice |
| 1502 | */ |
| 1503 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1504 | newcon->flags &= ~CON_PRINTBUFFER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1505 | |
| 1506 | /* |
| 1507 | * Put this console in the list - keep the |
| 1508 | * preferred driver at the head of the list. |
| 1509 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1510 | console_lock(); |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1511 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
| 1512 | newcon->next = console_drivers; |
| 1513 | console_drivers = newcon; |
| 1514 | if (newcon->next) |
| 1515 | newcon->next->flags &= ~CON_CONSDEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1516 | } else { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1517 | newcon->next = console_drivers->next; |
| 1518 | console_drivers->next = newcon; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1519 | } |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1520 | if (newcon->flags & CON_PRINTBUFFER) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1521 | /* |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1522 | * console_unlock(); will print out the buffered messages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1523 | * for us. |
| 1524 | */ |
| 1525 | spin_lock_irqsave(&logbuf_lock, flags); |
| 1526 | con_start = log_start; |
| 1527 | spin_unlock_irqrestore(&logbuf_lock, flags); |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 1528 | /* |
| 1529 | * We're about to replay the log buffer. Only do this to the |
| 1530 | * just-registered console to avoid excessive message spam to |
| 1531 | * the already-registered consoles. |
| 1532 | */ |
| 1533 | exclusive_console = newcon; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1534 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1535 | console_unlock(); |
Kay Sievers | fbc92a3 | 2010-12-01 18:51:05 +0100 | [diff] [blame] | 1536 | console_sysfs_notify(); |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 1537 | |
| 1538 | /* |
| 1539 | * By unregistering the bootconsoles after we enable the real console |
| 1540 | * we get the "console xxx enabled" message on all the consoles - |
| 1541 | * boot consoles, real consoles, etc - this is to ensure that end |
| 1542 | * users know there might be something in the kernel's log buffer that |
| 1543 | * went to the bootconsole (that they do not see on the real console) |
| 1544 | */ |
Fabio M. Di Nitto | 7bf6939 | 2011-03-22 16:34:20 -0700 | [diff] [blame] | 1545 | if (bcon && |
| 1546 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && |
| 1547 | !keep_bootcon) { |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 1548 | /* we need to iterate through twice, to make sure we print |
| 1549 | * everything out, before we unregister the console(s) |
| 1550 | */ |
| 1551 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", |
| 1552 | newcon->name, newcon->index); |
| 1553 | for_each_console(bcon) |
| 1554 | if (bcon->flags & CON_BOOT) |
| 1555 | unregister_console(bcon); |
| 1556 | } else { |
| 1557 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", |
| 1558 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
| 1559 | newcon->name, newcon->index); |
| 1560 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1561 | } |
| 1562 | EXPORT_SYMBOL(register_console); |
| 1563 | |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1564 | int unregister_console(struct console *console) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1565 | { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1566 | struct console *a, *b; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1567 | int res = 1; |
| 1568 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1569 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1570 | if (console->flags & CON_BRL) |
| 1571 | return braille_unregister_console(console); |
| 1572 | #endif |
| 1573 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1574 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1575 | if (console_drivers == console) { |
| 1576 | console_drivers=console->next; |
| 1577 | res = 0; |
Benjamin Herrenschmidt | e9b15b5 | 2005-11-23 13:37:44 -0800 | [diff] [blame] | 1578 | } else if (console_drivers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1579 | for (a=console_drivers->next, b=console_drivers ; |
| 1580 | a; b=a, a=b->next) { |
| 1581 | if (a == console) { |
| 1582 | b->next = a->next; |
| 1583 | res = 0; |
| 1584 | break; |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1585 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1586 | } |
| 1587 | } |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1588 | |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 1589 | /* |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1590 | * If this isn't the last console and it has CON_CONSDEV set, we |
| 1591 | * need to set it on the next preferred console. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1592 | */ |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 1593 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 1594 | console_drivers->flags |= CON_CONSDEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1595 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1596 | console_unlock(); |
Kay Sievers | fbc92a3 | 2010-12-01 18:51:05 +0100 | [diff] [blame] | 1597 | console_sysfs_notify(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1598 | return res; |
| 1599 | } |
| 1600 | EXPORT_SYMBOL(unregister_console); |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1601 | |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1602 | static int __init printk_late_init(void) |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 1603 | { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1604 | struct console *con; |
| 1605 | |
| 1606 | for_each_console(con) { |
Nishanth Aravamudan | 4c30c6f | 2011-08-25 15:59:11 -0700 | [diff] [blame] | 1607 | if (!keep_bootcon && con->flags & CON_BOOT) { |
Robin Getz | cb00e99 | 2007-08-21 23:14:58 -0400 | [diff] [blame] | 1608 | printk(KERN_INFO "turn off boot console %s%d\n", |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1609 | con->name, con->index); |
Sonic Zhang | 42c2c8c | 2009-08-06 15:58:11 -0700 | [diff] [blame] | 1610 | unregister_console(con); |
Robin Getz | cb00e99 | 2007-08-21 23:14:58 -0400 | [diff] [blame] | 1611 | } |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 1612 | } |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1613 | hotcpu_notifier(console_cpu_notify, 0); |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 1614 | return 0; |
| 1615 | } |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1616 | late_initcall(printk_late_init); |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 1617 | |
Joe Perches | 7ef3d2f | 2008-02-08 04:21:25 -0800 | [diff] [blame] | 1618 | #if defined CONFIG_PRINTK |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 1619 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1620 | /* |
| 1621 | * printk rate limiting, lifted from the networking subsystem. |
| 1622 | * |
Uwe Kleine-König | 641de9d | 2008-07-29 22:33:38 -0700 | [diff] [blame] | 1623 | * This enforces a rate limit: not more than 10 kernel messages |
| 1624 | * every 5s to make a denial-of-service attack impossible. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1625 | */ |
Uwe Kleine-König | 641de9d | 2008-07-29 22:33:38 -0700 | [diff] [blame] | 1626 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
| 1627 | |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 1628 | int __printk_ratelimit(const char *func) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1629 | { |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 1630 | return ___ratelimit(&printk_ratelimit_state, func); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1631 | } |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 1632 | EXPORT_SYMBOL(__printk_ratelimit); |
Andrew Morton | f46c483 | 2006-11-02 22:07:16 -0800 | [diff] [blame] | 1633 | |
| 1634 | /** |
| 1635 | * printk_timed_ratelimit - caller-controlled printk ratelimiting |
| 1636 | * @caller_jiffies: pointer to caller's state |
| 1637 | * @interval_msecs: minimum interval between prints |
| 1638 | * |
| 1639 | * printk_timed_ratelimit() returns true if more than @interval_msecs |
| 1640 | * milliseconds have elapsed since the last time printk_timed_ratelimit() |
| 1641 | * returned true. |
| 1642 | */ |
| 1643 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, |
| 1644 | unsigned int interval_msecs) |
| 1645 | { |
Guillaume Knispel | f2d28a2 | 2009-03-17 16:18:42 +0100 | [diff] [blame] | 1646 | if (*caller_jiffies == 0 |
| 1647 | || !time_in_range(jiffies, *caller_jiffies, |
| 1648 | *caller_jiffies |
| 1649 | + msecs_to_jiffies(interval_msecs))) { |
| 1650 | *caller_jiffies = jiffies; |
Andrew Morton | f46c483 | 2006-11-02 22:07:16 -0800 | [diff] [blame] | 1651 | return true; |
| 1652 | } |
| 1653 | return false; |
| 1654 | } |
| 1655 | EXPORT_SYMBOL(printk_timed_ratelimit); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1656 | |
| 1657 | static DEFINE_SPINLOCK(dump_list_lock); |
| 1658 | static LIST_HEAD(dump_list); |
| 1659 | |
| 1660 | /** |
| 1661 | * kmsg_dump_register - register a kernel log dumper. |
Randy Dunlap | 6485536 | 2009-12-17 15:27:27 -0800 | [diff] [blame] | 1662 | * @dumper: pointer to the kmsg_dumper structure |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1663 | * |
| 1664 | * Adds a kernel log dumper to the system. The dump callback in the |
| 1665 | * structure will be called when the kernel oopses or panics and must be |
| 1666 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. |
| 1667 | */ |
| 1668 | int kmsg_dump_register(struct kmsg_dumper *dumper) |
| 1669 | { |
| 1670 | unsigned long flags; |
| 1671 | int err = -EBUSY; |
| 1672 | |
| 1673 | /* The dump callback needs to be set */ |
| 1674 | if (!dumper->dump) |
| 1675 | return -EINVAL; |
| 1676 | |
| 1677 | spin_lock_irqsave(&dump_list_lock, flags); |
| 1678 | /* Don't allow registering multiple times */ |
| 1679 | if (!dumper->registered) { |
| 1680 | dumper->registered = 1; |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 1681 | list_add_tail_rcu(&dumper->list, &dump_list); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1682 | err = 0; |
| 1683 | } |
| 1684 | spin_unlock_irqrestore(&dump_list_lock, flags); |
| 1685 | |
| 1686 | return err; |
| 1687 | } |
| 1688 | EXPORT_SYMBOL_GPL(kmsg_dump_register); |
| 1689 | |
| 1690 | /** |
| 1691 | * kmsg_dump_unregister - unregister a kmsg dumper. |
Randy Dunlap | 6485536 | 2009-12-17 15:27:27 -0800 | [diff] [blame] | 1692 | * @dumper: pointer to the kmsg_dumper structure |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1693 | * |
| 1694 | * Removes a dump device from the system. Returns zero on success and |
| 1695 | * %-EINVAL otherwise. |
| 1696 | */ |
| 1697 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) |
| 1698 | { |
| 1699 | unsigned long flags; |
| 1700 | int err = -EINVAL; |
| 1701 | |
| 1702 | spin_lock_irqsave(&dump_list_lock, flags); |
| 1703 | if (dumper->registered) { |
| 1704 | dumper->registered = 0; |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 1705 | list_del_rcu(&dumper->list); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1706 | err = 0; |
| 1707 | } |
| 1708 | spin_unlock_irqrestore(&dump_list_lock, flags); |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 1709 | synchronize_rcu(); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1710 | |
| 1711 | return err; |
| 1712 | } |
| 1713 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); |
| 1714 | |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1715 | /** |
| 1716 | * kmsg_dump - dump kernel log to kernel message dumpers. |
| 1717 | * @reason: the reason (oops, panic etc) for dumping |
| 1718 | * |
| 1719 | * Iterate through each of the dump devices and call the oops/panic |
| 1720 | * callbacks with the log buffer. |
| 1721 | */ |
| 1722 | void kmsg_dump(enum kmsg_dump_reason reason) |
| 1723 | { |
| 1724 | unsigned long end; |
| 1725 | unsigned chars; |
| 1726 | struct kmsg_dumper *dumper; |
| 1727 | const char *s1, *s2; |
| 1728 | unsigned long l1, l2; |
| 1729 | unsigned long flags; |
| 1730 | |
| 1731 | /* Theoretically, the log could move on after we do this, but |
| 1732 | there's not a lot we can do about that. The new messages |
| 1733 | will overwrite the start of what we dump. */ |
| 1734 | spin_lock_irqsave(&logbuf_lock, flags); |
| 1735 | end = log_end & LOG_BUF_MASK; |
| 1736 | chars = logged_chars; |
| 1737 | spin_unlock_irqrestore(&logbuf_lock, flags); |
| 1738 | |
Andi Kleen | 8c4af38 | 2010-08-09 17:20:36 -0700 | [diff] [blame] | 1739 | if (chars > end) { |
| 1740 | s1 = log_buf + log_buf_len - chars + end; |
| 1741 | l1 = chars - end; |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1742 | |
| 1743 | s2 = log_buf; |
| 1744 | l2 = end; |
| 1745 | } else { |
| 1746 | s1 = ""; |
| 1747 | l1 = 0; |
| 1748 | |
Andi Kleen | 8c4af38 | 2010-08-09 17:20:36 -0700 | [diff] [blame] | 1749 | s2 = log_buf + end - chars; |
| 1750 | l2 = chars; |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1751 | } |
| 1752 | |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 1753 | rcu_read_lock(); |
| 1754 | list_for_each_entry_rcu(dumper, &dump_list, list) |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1755 | dumper->dump(dumper, reason, s1, l1, s2, l2); |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 1756 | rcu_read_unlock(); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 1757 | } |
Joe Perches | 7ef3d2f | 2008-02-08 04:21:25 -0800 | [diff] [blame] | 1758 | #endif |