X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=e3602d0755b0dd99c9fb47887fd67d371cdd5424;hb=99b36e68d3e9aa75439cbbcf04c78dc1b78f4049;hp=07ad9e7f7a66a85fb71a759c0408ccfcab60256a;hpb=4bb0057f996b1491f93a64879f4c53c83bc0f0c7;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/printk.c b/kernel/printk.c index 07ad9e7..e3602d0 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 @@ -73,7 +73,6 @@ EXPORT_SYMBOL(oops_in_progress); * driver system. */ static DECLARE_MUTEX(console_sem); -static DECLARE_MUTEX(secondary_console_sem); struct console *console_drivers; EXPORT_SYMBOL_GPL(console_drivers); @@ -233,45 +232,6 @@ static inline void boot_delay_msec(void) #endif /* - * Return the number of unread characters in the log buffer. - */ -static 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; -} - -/* * Commands to do_syslog: * * 0 -- Close the log. Currently a NOP. @@ -421,7 +381,7 @@ 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); } @@ -577,9 +537,6 @@ 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 @@ -593,6 +550,8 @@ 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, ...) @@ -659,7 +618,7 @@ static int acquire_console_semaphore_for_printk(unsigned int cpu) static const char recursion_bug_msg [] = KERN_CRIT "BUG: recent printk recursion!\n"; static int recursion_bug; - static int new_text_line = 1; +static int new_text_line = 1; static char printk_buf[1024]; asmlinkage int vprintk(const char *fmt, va_list args) @@ -702,7 +661,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) if (recursion_bug) { recursion_bug = 0; strcpy(printk_buf, recursion_bug_msg); - printed_len = sizeof(recursion_bug_msg); + printed_len = strlen(recursion_bug_msg); } /* Emit the output into the temporary buffer */ printed_len += vscnprintf(printk_buf + printed_len, @@ -782,11 +741,6 @@ EXPORT_SYMBOL(vprintk); #else -asmlinkage long sys_syslog(int type, char __user *buf, int len) -{ - return -ENOSYS; -} - static void call_console_drivers(unsigned start, unsigned end) { } @@ -933,15 +887,17 @@ 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; + up(&console_sem); } void resume_console(void) { if (!console_suspend_enabled) return; + down(&console_sem); console_suspended = 0; release_console_sem(); } @@ -957,11 +913,9 @@ void resume_console(void) void acquire_console_sem(void) { BUG_ON(in_interrupt()); - if (console_suspended) { - down(&secondary_console_sem); - return; - } down(&console_sem); + if (console_suspended) + return; console_locked = 1; console_may_schedule = 1; } @@ -971,6 +925,10 @@ int try_acquire_console_sem(void) { if (down_trylock(&console_sem)) return -1; + if (console_suspended) { + up(&console_sem); + return -1; + } console_locked = 1; console_may_schedule = 0; return 0; @@ -982,10 +940,25 @@ 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; } /** @@ -1009,7 +982,7 @@ void release_console_sem(void) unsigned wake_klogd = 0; if (console_suspended) { - up(&secondary_console_sem); + up(&console_sem); return; } @@ -1291,46 +1264,19 @@ 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->ops->write) - tty->ops->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) -{ - return __ratelimit(ratelimit_jiffies, ratelimit_burst); -} -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);