X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=c770e1a4e882289f66ae0e54451ba186f09c03d2;hb=a52865c239b1bc4f62e387509b1ad3415e476ee5;hp=7ba79ad895e4c41e9b4b658b10a37ab496008c51;hpb=b346671fa196abaf82ed3e1842f981209f7887af;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/printk.c b/kernel/printk.c index 7ba79ad..c770e1a 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -24,13 +24,14 @@ #include #include #include +#include #include /* For in_interrupt() */ -#include #include #include #include #include #include +#include #include @@ -52,8 +53,6 @@ int console_printk[4] = { DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ }; -EXPORT_SYMBOL(console_printk); - /* * Low lever drivers may need that to know if they can schedule in * their unblank() callback or not. So let's export it. @@ -67,6 +66,7 @@ EXPORT_SYMBOL(oops_in_progress); * driver system. */ static DECLARE_MUTEX(console_sem); +static DECLARE_MUTEX(secondary_console_sem); struct console *console_drivers; /* * This is used for debugging the mess that is the VT code by @@ -76,7 +76,7 @@ struct console *console_drivers; * path in the console code where we end up in places I want * locked without the console sempahore held */ -static int console_locked; +static int console_locked, console_suspended; /* * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars @@ -122,44 +122,6 @@ 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 */ -/* - * Setup a list of consoles. Called from init/main.c - */ -static int __init console_setup(char *str) -{ - char name[sizeof(console_cmdline[0].name)]; - char *s, *options; - int idx; - - /* - * Decode str into name, index, options. - */ - if (str[0] >= '0' && str[0] <= '9') { - strcpy(name, "ttyS"); - strncpy(name + 4, str, sizeof(name) - 5); - } else - strncpy(name, str, sizeof(name) - 1); - name[sizeof(name) - 1] = 0; - if ((options = strchr(str, ',')) != NULL) - *(options++) = 0; -#ifdef __sparc__ - if (!strcmp(str, "ttya")) - strcpy(name, "ttyS0"); - if (!strcmp(str, "ttyb")) - strcpy(name, "ttyS1"); -#endif - for (s = name; *s; s++) - if ((*s >= '0' && *s <= '9') || *s == ',') - break; - idx = simple_strtoul(s, NULL, 10); - *s = 0; - - add_preferred_console(name, idx, options); - return 1; -} - -__setup("console=", console_setup); - static int __init log_buf_len_setup(char *str) { unsigned long size = memparse(str, &str); @@ -364,18 +326,32 @@ static void __call_console_drivers(unsigned long start, unsigned long end) struct console *con; for (con = console_drivers; con; con = con->next) { - if ((con->flags & CON_ENABLED) && con->write) + if ((con->flags & CON_ENABLED) && con->write && + (cpu_online(smp_processor_id()) || + (con->flags & CON_ANYTIME))) con->write(con, &LOG_BUF(start), end - start); } } +static int __read_mostly ignore_loglevel; + +static int __init ignore_loglevel_setup(char *str) +{ + ignore_loglevel = 1; + printk(KERN_INFO "debug: ignoring loglevel setting.\n"); + + return 1; +} + +__setup("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) { - if (msg_log_level < console_loglevel && + if ((msg_log_level < console_loglevel || ignore_loglevel) && console_drivers && start != end) { if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) { /* wrapped write */ @@ -398,8 +374,7 @@ static void call_console_drivers(unsigned long start, unsigned long end) unsigned long cur_index, start_print; static int msg_level = -1; - if (((long)(start - end)) > 0) - BUG(); + BUG_ON(((long)(start - end)) > 0); cur_index = start; start_print = start; @@ -475,6 +450,7 @@ static int printk_time = 1; #else static int printk_time = 0; #endif +module_param(printk_time, int, S_IRUGO | S_IWUSR); static int __init printk_time_setup(char *str) { @@ -491,6 +467,18 @@ __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) +{ + struct console *con; + + for (con = console_drivers; con; con = con->next) + if (con->flags & CON_ANYTIME) + return 1; + + return 0; +} + /** * printk - print a kernel message * @fmt: format string @@ -541,7 +529,9 @@ asmlinkage int vprintk(const char *fmt, va_list args) zap_locks(); /* This stops the holder of console_sem just where we want him */ - spin_lock_irqsave(&logbuf_lock, flags); + local_irq_save(flags); + lockdep_off(); + spin_lock(&logbuf_lock); printk_cpu = smp_processor_id(); /* Emit the output into the temporary buffer */ @@ -604,27 +594,31 @@ asmlinkage int vprintk(const char *fmt, va_list args) log_level_unknown = 1; } - if (!cpu_online(smp_processor_id())) { + if (!down_trylock(&console_sem)) { /* - * Some console drivers may assume that per-cpu resources have - * been allocated. So don't allow them to be called by this - * CPU until it is officially up. We shouldn't be calling into - * random console drivers on a CPU which doesn't exist yet.. + * We own the drivers. We can drop the spinlock and + * let release_console_sem() print the text, maybe ... */ - printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); - goto out; - } - if (!down_trylock(&console_sem)) { console_locked = 1; + printk_cpu = UINT_MAX; + spin_unlock(&logbuf_lock); + /* - * We own the drivers. We can drop the spinlock and let - * release_console_sem() print the text + * 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. */ - printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); - console_may_schedule = 0; - release_console_sem(); + 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(); + local_irq_restore(flags); } else { /* * Someone else owns the drivers. We drop the spinlock, which @@ -632,9 +626,11 @@ asmlinkage int vprintk(const char *fmt, va_list args) * console drivers with the output which we just produced. */ printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); + spin_unlock(&logbuf_lock); + lockdep_on(); + local_irq_restore(flags); } -out: + preempt_enable(); return printed_len; } @@ -645,19 +641,52 @@ EXPORT_SYMBOL(vprintk); asmlinkage long sys_syslog(int type, char __user *buf, int len) { - return 0; + return -ENOSYS; } -int do_syslog(int type, char __user *buf, int len) +static void call_console_drivers(unsigned long start, unsigned long end) { - return 0; } -static void call_console_drivers(unsigned long start, unsigned long end) +#endif + +/* + * Set up a list of consoles. Called from init/main.c + */ +static int __init console_setup(char *str) { -} + char name[sizeof(console_cmdline[0].name)]; + char *s, *options; + int idx; + /* + * Decode str into name, index, options. + */ + if (str[0] >= '0' && str[0] <= '9') { + strcpy(name, "ttyS"); + strncpy(name + 4, str, sizeof(name) - 5); + } else { + strncpy(name, str, sizeof(name) - 1); + } + name[sizeof(name) - 1] = 0; + if ((options = strchr(str, ',')) != NULL) + *(options++) = 0; +#ifdef __sparc__ + if (!strcmp(str, "ttya")) + strcpy(name, "ttyS0"); + if (!strcmp(str, "ttyb")) + strcpy(name, "ttyS1"); #endif + for (s = name; *s; s++) + if ((*s >= '0' && *s <= '9') || *s == ',') + break; + idx = simple_strtoul(s, NULL, 10); + *s = 0; + + add_preferred_console(name, idx, options); + return 1; +} +__setup("console=", console_setup); /** * add_preferred_console - add a device to the list of preferred consoles. @@ -698,6 +727,26 @@ int __init add_preferred_console(char *name, int idx, char *options) return 0; } +#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND +/** + * suspend_console - suspend the console subsystem + * + * This disables printk() while we go into suspend states + */ +void suspend_console(void) +{ + printk("Suspending console(s)\n"); + acquire_console_sem(); + console_suspended = 1; +} + +void resume_console(void) +{ + console_suspended = 0; + release_console_sem(); +} +#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */ + /** * acquire_console_sem - lock the console system for exclusive use. * @@ -708,8 +757,11 @@ int __init add_preferred_console(char *name, int idx, char *options) */ void acquire_console_sem(void) { - if (in_interrupt()) - BUG(); + BUG_ON(in_interrupt()); + if (console_suspended) { + down(&secondary_console_sem); + return; + } down(&console_sem); console_locked = 1; console_may_schedule = 1; @@ -730,7 +782,6 @@ int is_console_locked(void) { return console_locked; } -EXPORT_SYMBOL(is_console_locked); /** * release_console_sem - unlock the console system @@ -752,6 +803,13 @@ void release_console_sem(void) unsigned long _con_start, _log_end; unsigned long wake_klogd = 0; + if (console_suspended) { + up(&secondary_console_sem); + return; + } + + console_may_schedule = 0; + for ( ; ; ) { spin_lock_irqsave(&logbuf_lock, flags); wake_klogd |= log_start - log_end; @@ -765,7 +823,6 @@ void release_console_sem(void) local_irq_restore(flags); } console_locked = 0; - console_may_schedule = 0; up(&console_sem); spin_unlock_irqrestore(&logbuf_lock, flags); if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) @@ -999,7 +1056,6 @@ void tty_write_message(struct tty_struct *tty, char *msg) tty->driver->write(tty, msg, strlen(msg)); return; } -EXPORT_SYMBOL_GPL(tty_write_message); /* * printk rate limiting, lifted from the networking subsystem. @@ -1050,3 +1106,23 @@ int printk_ratelimit(void) printk_ratelimit_burst); } EXPORT_SYMBOL(printk_ratelimit); + +/** + * printk_timed_ratelimit - caller-controlled printk ratelimiting + * @caller_jiffies: pointer to caller's state + * @interval_msecs: minimum interval between prints + * + * printk_timed_ratelimit() returns true if more than @interval_msecs + * milliseconds have elapsed since the last time printk_timed_ratelimit() + * returned true. + */ +bool printk_timed_ratelimit(unsigned long *caller_jiffies, + unsigned int interval_msecs) +{ + if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) { + *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs); + return true; + } + return false; +} +EXPORT_SYMBOL(printk_timed_ratelimit);