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Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c36
1 files changed, 34 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 33284adb2189..da8ca817eae3 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -53,7 +53,7 @@ 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.. */
-#define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */
+#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
/* We show everything that is MORE important than this.. */
#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
@@ -113,6 +113,11 @@ static unsigned con_start; /* Index into log_buf: next char to be sent to consol
static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */
/*
+ * If exclusive_console is non-NULL then only this console is to be printed to.
+ */
+static struct console *exclusive_console;
+
+/*
* Array of consoles built from command line options (console=)
*/
struct console_cmdline
@@ -476,6 +481,8 @@ static void __call_console_drivers(unsigned start, unsigned end)
struct console *con;
for_each_console(con) {
+ if (exclusive_console && con != exclusive_console)
+ continue;
if ((con->flags & CON_ENABLED) && con->write &&
(cpu_online(smp_processor_id()) ||
(con->flags & CON_ANYTIME)))
@@ -1230,6 +1237,11 @@ void console_unlock(void)
local_irq_restore(flags);
}
console_locked = 0;
+
+ /* Release the exclusive_console once it is used */
+ if (unlikely(exclusive_console))
+ exclusive_console = NULL;
+
up(&console_sem);
spin_unlock_irqrestore(&logbuf_lock, flags);
if (wake_klogd)
@@ -1316,6 +1328,18 @@ void console_start(struct console *console)
}
EXPORT_SYMBOL(console_start);
+static int __read_mostly keep_bootcon;
+
+static int __init keep_bootcon_setup(char *str)
+{
+ keep_bootcon = 1;
+ printk(KERN_INFO "debug: skip boot console de-registration.\n");
+
+ return 0;
+}
+
+early_param("keep_bootcon", keep_bootcon_setup);
+
/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
@@ -1452,6 +1476,12 @@ void register_console(struct console *newcon)
spin_lock_irqsave(&logbuf_lock, flags);
con_start = log_start;
spin_unlock_irqrestore(&logbuf_lock, flags);
+ /*
+ * We're about to replay the log buffer. Only do this to the
+ * just-registered console to avoid excessive message spam to
+ * the already-registered consoles.
+ */
+ exclusive_console = newcon;
}
console_unlock();
console_sysfs_notify();
@@ -1463,7 +1493,9 @@ void register_console(struct console *newcon)
* users know there might be something in the kernel's log buffer that
* went to the bootconsole (that they do not see on the real console)
*/
- if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) {
+ if (bcon &&
+ ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
+ !keep_bootcon) {
/* we need to iterate through twice, to make sure we print
* everything out, before we unregister the console(s)
*/