/*
* Can we actually use the console at this time on this cpu?
*
* 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.
*/
static inline int can_use_console(unsigned int cpu)
{
#ifdef CONFIG_HOTPLUG_CPU
if (!cpu_active(cpu) && cpu_hotplug_inprogress())
return 0;
#endif
return cpu_online(cpu) || have_callable_console();
}
/*
* Can we actually use the console at this time on this cpu?
*
* 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.
*/
static inline int can_use_console(unsigned int cpu)
{
return cpu_online(cpu) || have_callable_console();
}
asmlinkage int vprintk(const char *fmt, va_list args)
{
unsigned long flags;
int printed_len;
char *p;
static char printk_buf[1024];
static int log_level_unknown = 1;
boot_delay_msec();
preempt_disable();
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 */
raw_local_irq_save(flags);
lockdep_off();
spin_lock(&logbuf_lock);
printk_cpu = smp_processor_id();
/* Emit the output into the temporary buffer */
printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args);
/*
* Copy the output into log_buf. If the caller didn't provide
* appropriate log level tags, we insert them here
*/
for (p = printk_buf; *p; p++) {
if (log_level_unknown) {
/* log_level_unknown signals the start of a new line */
if (printk_time) {
int loglev_char;
char tbuf[50], *tp;
unsigned tlen;
unsigned long long t;
unsigned long nanosec_rem;
/*
* force the log level token to be
* before the time output.
*/
if (p[0] == '<' && p[1] >='0' &&
p[1] <= '7' && p[2] == '>') {
loglev_char = p[1];
p += 3;
printed_len -= 3;
} else {
loglev_char = default_message_loglevel
+ '0';
}
t = printk_clock();
nanosec_rem = do_div(t, 1000000000);
tlen = sprintf(tbuf,
"<%c>[%5lu.%06lu] ",
loglev_char,
(unsigned long)t,
nanosec_rem/1000);
for (tp = tbuf; tp < tbuf + tlen; tp++)
emit_log_char(*tp);
printed_len += tlen;
} else {
if (p[0] != '<' || p[1] < '0' ||
p[1] > '7' || p[2] != '>') {
emit_log_char('<');
emit_log_char(default_message_loglevel
+ '0');
emit_log_char('>');
printed_len += 3;
}
}
log_level_unknown = 0;
if (!*p)
break;
}
emit_log_char(*p);
if (*p == '\n')
log_level_unknown = 1;
}
if (!down_trylock(&console_sem)) {
/*
* We own the drivers. We can drop the spinlock and
* let release_console_sem() print the text, maybe ...
*/
console_locked = 1;
printk_cpu = UINT_MAX;
spin_unlock(&logbuf_lock);
/*
* 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.
*/
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();
raw_local_irq_restore(flags);
} else {
/*
* Someone else owns the drivers. We drop the spinlock, which
* allows the semaphore holder to proceed and to call the
* console drivers with the output which we just produced.
*/
printk_cpu = UINT_MAX;
spin_unlock(&logbuf_lock);
lockdep_on();
raw_local_irq_restore(flags);
}
preempt_enable();
return printed_len;
}