X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=65ca0688f86f1b78fafd144671a17015b2fd1525;hb=153d7f3fcae7ed4e19328549aa9467acdfbced10;hp=19a95561929478ffc99ac1552cf3ab645ec16bc1;hpb=4b2d9cf00962d0a0e697f887f3ecaa155cbde555;p=powerpc.git

diff --git a/kernel/printk.c b/kernel/printk.c
index 19a9556192..65ca0688f8 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -24,8 +24,8 @@
 #include <linux/console.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/moduleparam.h>
 #include <linux/interrupt.h>			/* For in_interrupt() */
-#include <linux/config.h>
 #include <linux/delay.h>
 #include <linux/smp.h>
 #include <linux/security.h>
@@ -52,7 +52,7 @@ int console_printk[4] = {
 	DEFAULT_CONSOLE_LOGLEVEL,	/* default_console_loglevel */
 };
 
-EXPORT_SYMBOL(console_printk);
+EXPORT_UNUSED_SYMBOL(console_printk);  /*  June 2006  */
 
 /*
  * Low lever drivers may need that to know if they can schedule in
@@ -327,7 +327,9 @@ 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);
 	}
 }
@@ -437,6 +439,7 @@ 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)
 {
@@ -453,6 +456,18 @@ __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
@@ -503,7 +518,9 @@ 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 */
@@ -566,27 +583,31 @@ 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
@@ -594,9 +615,11 @@ 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;
 }
@@ -750,7 +773,7 @@ int is_console_locked(void)
 {
 	return console_locked;
 }
-EXPORT_SYMBOL(is_console_locked);
+EXPORT_UNUSED_SYMBOL(is_console_locked);  /*  June 2006  */
 
 /**
  * release_console_sem - unlock the console system
@@ -792,8 +815,15 @@ void release_console_sem(void)
 	console_may_schedule = 0;
 	up(&console_sem);
 	spin_unlock_irqrestore(&logbuf_lock, flags);
-	if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait))
-		wake_up_interruptible(&log_wait);
+	if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) {
+		/*
+		 * If we printk from within the lock dependency code,
+		 * from within the scheduler code, then do not lock
+		 * up due to self-recursion:
+		 */
+		if (!lockdep_internal())
+			wake_up_interruptible(&log_wait);
+	}
 }
 EXPORT_SYMBOL(release_console_sem);