X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=69188f226a93251009d22d6dc453ce3d59220816;hb=a571bbeafbcc501d9989fbce1cddcd810bd51d71;hp=5f9d053699f9548c7002d7717b7a345e2d63d03d;hpb=d713f519332e029d43eca8462629314eee1ded86;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/printk.c b/kernel/printk.c index 5f9d053..69188f2 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -13,7 +13,7 @@ * Fixed SMP synchronization, 08/08/99, Manfred Spraul * manfred@colorfullife.com * Rewrote bits to get rid of console_lock - * 01Mar01 Andrew Morton + * 01Mar01 Andrew Morton */ #include @@ -32,10 +32,16 @@ #include #include #include -#include #include +/* + * Architectures can override it: + */ +void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) +{ +} + #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) /* printk's without a loglevel use this.. */ @@ -69,6 +75,8 @@ EXPORT_SYMBOL(oops_in_progress); static DECLARE_MUTEX(console_sem); static DECLARE_MUTEX(secondary_console_sem); struct console *console_drivers; +EXPORT_SYMBOL_GPL(console_drivers); + /* * This is used for debugging the mess that is the VT code by * keeping track if we have the console semaphore held. It's @@ -86,16 +94,16 @@ static int console_locked, console_suspended; */ static DEFINE_SPINLOCK(logbuf_lock); -#define LOG_BUF_MASK (log_buf_len-1) +#define LOG_BUF_MASK (log_buf_len-1) #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) /* * The indices into log_buf are not constrained to log_buf_len - they * must be masked before subscripting */ -static unsigned long log_start; /* Index into log_buf: next char to be read by syslog() */ -static unsigned long con_start; /* Index into log_buf: next char to be sent to consoles */ -static unsigned long log_end; /* Index into log_buf: most-recently-written-char + 1 */ +static unsigned log_start; /* Index into log_buf: next char to be read by syslog() */ +static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */ +static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ /* * Array of consoles built from command line options (console=) @@ -105,6 +113,9 @@ struct console_cmdline char name[8]; /* Name of the driver */ int index; /* Minor dev. to use */ char *options; /* Options for the driver */ +#ifdef CONFIG_A11Y_BRAILLE_CONSOLE + char *brl_options; /* Options for braille driver */ +#endif }; #define MAX_CMDLINECONSOLES 8 @@ -112,6 +123,8 @@ struct console_cmdline static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; static int selected_console = -1; static int preferred_console = -1; +int console_set_on_cmdline; +EXPORT_SYMBOL(console_set_on_cmdline); /* Flag: console code may call schedule() */ static int console_may_schedule; @@ -121,17 +134,17 @@ static int console_may_schedule; static char __log_buf[__LOG_BUF_LEN]; static char *log_buf = __log_buf; static int log_buf_len = __LOG_BUF_LEN; -static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */ +static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ static int __init log_buf_len_setup(char *str) { - unsigned long size = memparse(str, &str); + unsigned size = memparse(str, &str); unsigned long flags; if (size) size = roundup_pow_of_two(size); if (size > log_buf_len) { - unsigned long start, dest_idx, offset; + unsigned start, dest_idx, offset; char *new_log_buf; new_log_buf = alloc_bootmem(size); @@ -220,58 +233,6 @@ static inline void boot_delay_msec(void) #endif /* - * Return the number of unread characters in the log buffer. - */ -int log_buf_get_len(void) -{ - return logged_chars; -} - -/* - * Copy a range of characters from the log buffer. - */ -int log_buf_copy(char *dest, int idx, int len) -{ - int ret, max; - bool took_lock = false; - - if (!oops_in_progress) { - spin_lock_irq(&logbuf_lock); - took_lock = true; - } - - max = log_buf_get_len(); - if (idx < 0 || idx >= max) { - ret = -1; - } else { - if (len > max) - len = max; - ret = len; - idx += (log_end - max); - while (len-- > 0) - dest[len] = LOG_BUF(idx + len); - } - - if (took_lock) - spin_unlock_irq(&logbuf_lock); - - return ret; -} - -/* - * Extract a single character from the log buffer. - */ -int log_buf_read(int idx) -{ - char ret; - - if (log_buf_copy(&ret, idx, 1) == 1) - return ret; - else - return -1; -} - -/* * Commands to do_syslog: * * 0 -- Close the log. Currently a NOP. @@ -288,7 +249,7 @@ int log_buf_read(int idx) */ int do_syslog(int type, char __user *buf, int len) { - unsigned long i, j, limit, count; + unsigned i, j, limit, count; int do_clear = 0; char c; int error = 0; @@ -421,7 +382,7 @@ out: return error; } -asmlinkage long sys_syslog(int type, char __user *buf, int len) +SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) { return do_syslog(type, buf, len); } @@ -429,7 +390,7 @@ asmlinkage long sys_syslog(int type, char __user *buf, int len) /* * Call the console drivers on a range of log_buf */ -static void __call_console_drivers(unsigned long start, unsigned long end) +static void __call_console_drivers(unsigned start, unsigned end) { struct console *con; @@ -448,16 +409,16 @@ static int __init ignore_loglevel_setup(char *str) ignore_loglevel = 1; printk(KERN_INFO "debug: ignoring loglevel setting.\n"); - return 1; + return 0; } -__setup("ignore_loglevel", ignore_loglevel_setup); +early_param("ignore_loglevel", ignore_loglevel_setup); /* * Write out chars from start to end - 1 inclusive */ -static void _call_console_drivers(unsigned long start, - unsigned long end, int msg_log_level) +static void _call_console_drivers(unsigned start, + unsigned end, int msg_log_level) { if ((msg_log_level < console_loglevel || ignore_loglevel) && console_drivers && start != end) { @@ -477,12 +438,12 @@ static void _call_console_drivers(unsigned long start, * log_buf[start] to log_buf[end - 1]. * The console_sem must be held. */ -static void call_console_drivers(unsigned long start, unsigned long end) +static void call_console_drivers(unsigned start, unsigned end) { - unsigned long cur_index, start_print; + unsigned cur_index, start_print; static int msg_level = -1; - BUG_ON(((long)(start - end)) > 0); + BUG_ON(((int)(start - end)) > 0); cur_index = start; start_print = start; @@ -560,24 +521,6 @@ static int printk_time = 0; #endif module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); -static int __init printk_time_setup(char *str) -{ - if (*str) - return 0; - printk_time = 1; - printk(KERN_NOTICE "The 'time' option is deprecated and " - "is scheduled for removal in early 2008\n"); - printk(KERN_NOTICE "Use 'printk.time=' instead\n"); - return 1; -} - -__setup("time", printk_time_setup); - -__attribute__((weak)) unsigned long long printk_clock(void) -{ - return sched_clock(); -} - /* Check if we have any console registered that can be called early in boot. */ static int have_callable_console(void) { @@ -595,9 +538,6 @@ static int have_callable_console(void) * @fmt: format string * * This is printk(). It can be called from any context. We want it to work. - * Be aware of the fact that if oops_in_progress is not set, we might try to - * wake klogd up which could deadlock on runqueue lock if printk() is called - * from scheduler code. * * We try to grab the console_sem. If we succeed, it's easy - we log the output and * call the console drivers. If we fail to get the semaphore we place the output @@ -611,6 +551,8 @@ static int have_callable_console(void) * * See also: * printf(3) + * + * See the vsnprintf() documentation for format string extensions over C99. */ asmlinkage int printk(const char *fmt, ...) @@ -628,17 +570,63 @@ asmlinkage int printk(const char *fmt, ...) /* cpu currently holding logbuf_lock */ static volatile unsigned int printk_cpu = UINT_MAX; -const char printk_recursion_bug_msg [] = - KERN_CRIT "BUG: recent printk recursion!\n"; -static int printk_recursion_bug; +/* + * Can we actually use the console at this time on this cpu? + * + * Console drivers may assume that per-cpu resources have + * been allocated. So unless they're explicitly marked as + * being able to cope (CON_ANYTIME) don't call them until + * this CPU is officially up. + */ +static inline int can_use_console(unsigned int cpu) +{ + return cpu_online(cpu) || have_callable_console(); +} -asmlinkage int vprintk(const char *fmt, va_list args) +/* + * Try to get console ownership to actually show the kernel + * messages from a 'printk'. Return true (and with the + * console_semaphore held, and 'console_locked' set) if it + * is successful, false otherwise. + * + * This gets called with the 'logbuf_lock' spinlock held and + * interrupts disabled. It should return with 'lockbuf_lock' + * released but interrupts still disabled. + */ +static int acquire_console_semaphore_for_printk(unsigned int cpu) { - static int log_level_unknown = 1; - static char printk_buf[1024]; + int retval = 0; - unsigned long flags; + if (!try_acquire_console_sem()) { + retval = 1; + + /* + * If we can't use the console, we need to release + * the console semaphore by hand to avoid flushing + * the buffer. We need to hold the console semaphore + * in order to do this test safely. + */ + if (!can_use_console(cpu)) { + console_locked = 0; + up(&console_sem); + retval = 0; + } + } + printk_cpu = UINT_MAX; + spin_unlock(&logbuf_lock); + return retval; +} +static const char recursion_bug_msg [] = + KERN_CRIT "BUG: recent printk recursion!\n"; +static int recursion_bug; +static int new_text_line = 1; +static char printk_buf[1024]; + +asmlinkage int vprintk(const char *fmt, va_list args) +{ int printed_len = 0; + int current_log_level = default_message_loglevel; + unsigned long flags; int this_cpu; char *p; @@ -661,7 +649,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) * it can be printed at the next appropriate moment: */ if (!oops_in_progress) { - printk_recursion_bug = 1; + recursion_bug = 1; goto out_restore_irqs; } zap_locks(); @@ -671,109 +659,80 @@ asmlinkage int vprintk(const char *fmt, va_list args) spin_lock(&logbuf_lock); printk_cpu = this_cpu; - if (printk_recursion_bug) { - printk_recursion_bug = 0; - strcpy(printk_buf, printk_recursion_bug_msg); - printed_len = sizeof(printk_recursion_bug_msg); + if (recursion_bug) { + recursion_bug = 0; + strcpy(printk_buf, recursion_bug_msg); + printed_len = strlen(recursion_bug_msg); } /* Emit the output into the temporary buffer */ printed_len += vscnprintf(printk_buf + printed_len, - sizeof(printk_buf), fmt, args); + sizeof(printk_buf) - printed_len, fmt, args); + /* * Copy the output into log_buf. If the caller didn't provide * appropriate log level tags, we insert them here */ for (p = printk_buf; *p; p++) { - if (log_level_unknown) { - /* log_level_unknown signals the start of a new line */ + if (new_text_line) { + /* If a token, set current_log_level and skip over */ + if (p[0] == '<' && p[1] >= '0' && p[1] <= '7' && + p[2] == '>') { + current_log_level = p[1] - '0'; + p += 3; + printed_len -= 3; + } + + /* Always output the token */ + emit_log_char('<'); + emit_log_char(current_log_level + '0'); + emit_log_char('>'); + printed_len += 3; + new_text_line = 0; + if (printk_time) { - int loglev_char; + /* Follow the token with the time */ char tbuf[50], *tp; unsigned tlen; unsigned long long t; unsigned long nanosec_rem; - /* - * force the log level token to be - * before the time output. - */ - if (p[0] == '<' && p[1] >='0' && - p[1] <= '7' && p[2] == '>') { - loglev_char = p[1]; - p += 3; - printed_len -= 3; - } else { - loglev_char = default_message_loglevel - + '0'; - } t = cpu_clock(printk_cpu); nanosec_rem = do_div(t, 1000000000); - tlen = sprintf(tbuf, - "<%c>[%5lu.%06lu] ", - loglev_char, - (unsigned long)t, - nanosec_rem/1000); + tlen = sprintf(tbuf, "[%5lu.%06lu] ", + (unsigned long) t, + nanosec_rem / 1000); for (tp = tbuf; tp < tbuf + tlen; tp++) emit_log_char(*tp); printed_len += tlen; - } else { - if (p[0] != '<' || p[1] < '0' || - p[1] > '7' || p[2] != '>') { - emit_log_char('<'); - emit_log_char(default_message_loglevel - + '0'); - emit_log_char('>'); - printed_len += 3; - } } - log_level_unknown = 0; + if (!*p) break; } + emit_log_char(*p); if (*p == '\n') - log_level_unknown = 1; + new_text_line = 1; } - if (!down_trylock(&console_sem)) { - /* - * We own the drivers. We can drop the spinlock and - * let release_console_sem() print the text, maybe ... - */ - console_locked = 1; - printk_cpu = UINT_MAX; - spin_unlock(&logbuf_lock); + /* + * Try to acquire and then immediately release the + * console semaphore. The release will do all the + * actual magic (print out buffers, wake up klogd, + * etc). + * + * The acquire_console_semaphore_for_printk() function + * will release 'logbuf_lock' regardless of whether it + * actually gets the semaphore or not. + */ + if (acquire_console_semaphore_for_printk(this_cpu)) + release_console_sem(); - /* - * Console drivers may assume that per-cpu resources have - * been allocated. So unless they're explicitly marked as - * being able to cope (CON_ANYTIME) don't call them until - * this CPU is officially up. - */ - if (cpu_online(smp_processor_id()) || have_callable_console()) { - console_may_schedule = 0; - release_console_sem(); - } else { - /* Release by hand to avoid flushing the buffer. */ - console_locked = 0; - up(&console_sem); - } - lockdep_on(); - raw_local_irq_restore(flags); - } else { - /* - * Someone else owns the drivers. We drop the spinlock, which - * allows the semaphore holder to proceed and to call the - * console drivers with the output which we just produced. - */ - printk_cpu = UINT_MAX; - spin_unlock(&logbuf_lock); - lockdep_on(); + lockdep_on(); out_restore_irqs: - raw_local_irq_restore(flags); - } + raw_local_irq_restore(flags); preempt_enable(); return printed_len; @@ -783,26 +742,66 @@ EXPORT_SYMBOL(vprintk); #else -asmlinkage long sys_syslog(int type, char __user *buf, int len) +static void call_console_drivers(unsigned start, unsigned end) { - return -ENOSYS; } -static void call_console_drivers(unsigned long start, unsigned long end) +#endif + +static int __add_preferred_console(char *name, int idx, char *options, + char *brl_options) { -} + struct console_cmdline *c; + int i; + /* + * See if this tty is not yet registered, and + * if we have a slot free. + */ + for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) + if (strcmp(console_cmdline[i].name, name) == 0 && + console_cmdline[i].index == idx) { + if (!brl_options) + selected_console = i; + return 0; + } + if (i == MAX_CMDLINECONSOLES) + return -E2BIG; + if (!brl_options) + selected_console = i; + c = &console_cmdline[i]; + strlcpy(c->name, name, sizeof(c->name)); + c->options = options; +#ifdef CONFIG_A11Y_BRAILLE_CONSOLE + c->brl_options = brl_options; #endif - + c->index = idx; + return 0; +} /* * Set up a list of consoles. Called from init/main.c */ static int __init console_setup(char *str) { char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ - char *s, *options; + char *s, *options, *brl_options = NULL; int idx; +#ifdef CONFIG_A11Y_BRAILLE_CONSOLE + if (!memcmp(str, "brl,", 4)) { + brl_options = ""; + str += 4; + } else if (!memcmp(str, "brl=", 4)) { + brl_options = str + 4; + str = strchr(brl_options, ','); + if (!str) { + printk(KERN_ERR "need port name after brl=\n"); + return 1; + } + *(str++) = 0; + } +#endif + /* * Decode str into name, index, options. */ @@ -827,7 +826,8 @@ static int __init console_setup(char *str) idx = simple_strtoul(s, NULL, 10); *s = 0; - add_preferred_console(buf, idx, options); + __add_preferred_console(buf, idx, options, brl_options); + console_set_on_cmdline = 1; return 1; } __setup("console=", console_setup); @@ -847,28 +847,7 @@ __setup("console=", console_setup); */ int add_preferred_console(char *name, int idx, char *options) { - struct console_cmdline *c; - int i; - - /* - * See if this tty is not yet registered, and - * if we have a slot free. - */ - for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) - if (strcmp(console_cmdline[i].name, name) == 0 && - console_cmdline[i].index == idx) { - selected_console = i; - return 0; - } - if (i == MAX_CMDLINECONSOLES) - return -E2BIG; - selected_console = i; - c = &console_cmdline[i]; - memcpy(c->name, name, sizeof(c->name)); - c->name[sizeof(c->name) - 1] = 0; - c->options = options; - c->index = idx; - return 0; + return __add_preferred_console(name, idx, options, NULL); } int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) @@ -880,7 +859,7 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha if (strcmp(console_cmdline[i].name, name) == 0 && console_cmdline[i].index == idx) { c = &console_cmdline[i]; - memcpy(c->name, name_new, sizeof(c->name)); + strlcpy(c->name, name_new, sizeof(c->name)); c->name[sizeof(c->name) - 1] = 0; c->options = options; c->index = idx_new; @@ -909,7 +888,7 @@ void suspend_console(void) { if (!console_suspend_enabled) return; - printk("Suspending console(s)\n"); + printk("Suspending console(s) (use no_console_suspend to debug)\n"); acquire_console_sem(); console_suspended = 1; } @@ -958,10 +937,25 @@ int is_console_locked(void) return console_locked; } -void wake_up_klogd(void) +static DEFINE_PER_CPU(int, printk_pending); + +void printk_tick(void) { - if (!oops_in_progress && waitqueue_active(&log_wait)) + if (__get_cpu_var(printk_pending)) { + __get_cpu_var(printk_pending) = 0; wake_up_interruptible(&log_wait); + } +} + +int printk_needs_cpu(int cpu) +{ + return per_cpu(printk_pending, cpu); +} + +void wake_up_klogd(void) +{ + if (waitqueue_active(&log_wait)) + __raw_get_cpu_var(printk_pending) = 1; } /** @@ -981,8 +975,8 @@ void wake_up_klogd(void) void release_console_sem(void) { unsigned long flags; - unsigned long _con_start, _log_end; - unsigned long wake_klogd = 0; + unsigned _con_start, _log_end; + unsigned wake_klogd = 0; if (console_suspended) { up(&secondary_console_sem); @@ -1000,7 +994,9 @@ void release_console_sem(void) _log_end = log_end; con_start = log_end; /* Flush */ spin_unlock(&logbuf_lock); + stop_critical_timings(); /* don't trace print latency */ call_console_drivers(_con_start, _log_end); + start_critical_timings(); local_irq_restore(flags); } console_locked = 0; @@ -1131,8 +1127,11 @@ void register_console(struct console *console) console->index = 0; if (console->setup == NULL || console->setup(console, NULL) == 0) { - console->flags |= CON_ENABLED | CON_CONSDEV; - preferred_console = 0; + console->flags |= CON_ENABLED; + if (console->device) { + console->flags |= CON_CONSDEV; + preferred_console = 0; + } } } @@ -1149,6 +1148,16 @@ void register_console(struct console *console) continue; if (console->index < 0) console->index = console_cmdline[i].index; +#ifdef CONFIG_A11Y_BRAILLE_CONSOLE + if (console_cmdline[i].brl_options) { + console->flags |= CON_BRL; + braille_register_console(console, + console_cmdline[i].index, + console_cmdline[i].options, + console_cmdline[i].brl_options); + return; + } +#endif if (console->setup && console->setup(console, console_cmdline[i].options) != 0) break; @@ -1207,6 +1216,11 @@ int unregister_console(struct console *console) struct console *a, *b; int res = 1; +#ifdef CONFIG_A11Y_BRAILLE_CONSOLE + if (console->flags & CON_BRL) + return braille_unregister_console(console); +#endif + acquire_console_sem(); if (console_drivers == console) { console_drivers=console->next; @@ -1247,69 +1261,19 @@ static int __init disable_boot_consoles(void) } late_initcall(disable_boot_consoles); -/** - * tty_write_message - write a message to a certain tty, not just the console. - * @tty: the destination tty_struct - * @msg: the message to write - * - * This is used for messages that need to be redirected to a specific tty. - * We don't put it into the syslog queue right now maybe in the future if - * really needed. - */ -void tty_write_message(struct tty_struct *tty, char *msg) -{ - if (tty && tty->driver->write) - tty->driver->write(tty, msg, strlen(msg)); - return; -} +#if defined CONFIG_PRINTK /* * printk rate limiting, lifted from the networking subsystem. * - * This enforces a rate limit: not more than one kernel message - * every printk_ratelimit_jiffies to make a denial-of-service - * attack impossible. + * This enforces a rate limit: not more than 10 kernel messages + * every 5s to make a denial-of-service attack impossible. */ -int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst) -{ - static DEFINE_SPINLOCK(ratelimit_lock); - static unsigned long toks = 10 * 5 * HZ; - static unsigned long last_msg; - static int missed; - unsigned long flags; - unsigned long now = jiffies; - - spin_lock_irqsave(&ratelimit_lock, flags); - toks += now - last_msg; - last_msg = now; - if (toks > (ratelimit_burst * ratelimit_jiffies)) - toks = ratelimit_burst * ratelimit_jiffies; - if (toks >= ratelimit_jiffies) { - int lost = missed; - - missed = 0; - toks -= ratelimit_jiffies; - spin_unlock_irqrestore(&ratelimit_lock, flags); - if (lost) - printk(KERN_WARNING "printk: %d messages suppressed.\n", lost); - return 1; - } - missed++; - spin_unlock_irqrestore(&ratelimit_lock, flags); - return 0; -} -EXPORT_SYMBOL(__printk_ratelimit); - -/* minimum time in jiffies between messages */ -int printk_ratelimit_jiffies = 5 * HZ; - -/* number of messages we send before ratelimiting */ -int printk_ratelimit_burst = 10; +DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); int printk_ratelimit(void) { - return __printk_ratelimit(printk_ratelimit_jiffies, - printk_ratelimit_burst); + return __ratelimit(&printk_ratelimit_state); } EXPORT_SYMBOL(printk_ratelimit); @@ -1332,3 +1296,4 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies, return false; } EXPORT_SYMBOL(printk_timed_ratelimit); +#endif