#include <linux/jiffies.h>
#include <linux/nmi.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>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
+#include <linux/vs_context.h>
#include <linux/vserver/cvirt.h>
#include <asm/uaccess.h>
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
* path in the console code where we end up in places I want
* locked without the console sempahore held
*/
-static int console_locked;
-int console_suspended;
+static int console_locked, console_suspended;
/*
* logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
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);
}
}
#else
static int printk_time = 0;
#endif
+module_param(printk_time, int, S_IRUGO | S_IWUSR);
static int __init printk_time_setup(char *str)
{
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
char *p;
static char printk_buf[1024];
static int log_level_unknown = 1;
+ struct vx_info_save vxis;
preempt_disable();
+ __enter_vx_admin(&vxis);
if (unlikely(oops_in_progress) && printk_cpu == smp_processor_id())
/* If a crash is occurring during printk() on this CPU,
* make sure we can't deadlock */
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 */
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
* 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:
+
+ __leave_vx_admin(&vxis);
preempt_enable();
return printed_len;
}
return 0;
}
+/**
+ * suspend_console - suspend the console subsystem
+ *
+ * This disables printk() while we go into suspend states
+ */
+void suspend_console(void)
+{
+ acquire_console_sem();
+ console_suspended = 1;
+}
+
+void resume_console(void)
+{
+ console_suspended = 0;
+ release_console_sem();
+}
+
/**
* acquire_console_sem - lock the console system for exclusive use.
*
*/
void acquire_console_sem(void)
{
+ BUG_ON(in_interrupt());
if (console_suspended) {
down(&secondary_console_sem);
return;
}
-
- BUG_ON(in_interrupt());
down(&console_sem);
console_locked = 1;
console_may_schedule = 1;
{
return console_locked;
}
-EXPORT_SYMBOL(is_console_locked);
+EXPORT_UNUSED_SYMBOL(is_console_locked); /* June 2006 */
/**
* release_console_sem - unlock the console system
return;
}
+ console_may_schedule = 0;
+
for ( ; ; ) {
spin_lock_irqsave(&logbuf_lock, flags);
wake_klogd |= log_start - log_end;
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))
- 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);
git://git.onelab.eu / linux-2.6.git / blobdiff