* elsewhere, in preparation for a serial line console (someday).
* Ted Ts'o, 2/11/93.
* Modified for sysctl support, 1/8/97, Chris Horn.
- * Fixed SMP synchronization, 08/08/99, Manfred Spraul
- * manfreds@colorfullife.com
+ * Fixed SMP synchronization, 08/08/99, Manfred Spraul
+ * manfred@colorfullife.com
* Rewrote bits to get rid of console_lock
* 01Mar01 Andrew Morton <andrewm@uow.edu.au>
*/
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
-#include <linux/smp_lock.h>
#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>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
+#include <linux/jiffies.h>
#include <asm/uaccess.h>
DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
};
-EXPORT_SYMBOL(console_printk);
-
/*
- * Low lever drivers may need that to know if they can schedule in
+ * Low level drivers may need that to know if they can schedule in
* their unblank() callback or not. So let's export it.
*/
int oops_in_progress;
* driver system.
*/
static DECLARE_MUTEX(console_sem);
+static DECLARE_MUTEX(secondary_console_sem);
struct console *console_drivers;
/*
* This is used for debugging the mess that is the VT code by
* path in the console code where we end up in places I want
* locked without the console sempahore held
*/
-static int console_locked;
+static int console_locked, console_suspended;
/*
* logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
static int log_buf_len = __LOG_BUF_LEN;
static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
-/*
- * Setup a list of consoles. Called from init/main.c
- */
-static int __init console_setup(char *str)
-{
- char name[sizeof(console_cmdline[0].name)];
- char *s, *options;
- int idx;
-
- /*
- * Decode str into name, index, options.
- */
- if (str[0] >= '0' && str[0] <= '9') {
- strcpy(name, "ttyS");
- strncpy(name + 4, str, sizeof(name) - 5);
- } else
- strncpy(name, str, sizeof(name) - 1);
- name[sizeof(name) - 1] = 0;
- if ((options = strchr(str, ',')) != NULL)
- *(options++) = 0;
-#ifdef __sparc__
- if (!strcmp(str, "ttya"))
- strcpy(name, "ttyS0");
- if (!strcmp(str, "ttyb"))
- strcpy(name, "ttyS1");
-#endif
- for(s = name; *s; s++)
- if ((*s >= '0' && *s <= '9') || *s == ',')
- break;
- idx = simple_strtoul(s, NULL, 10);
- *s = 0;
-
- add_preferred_console(name, idx, options);
- return 1;
-}
-
-__setup("console=", console_setup);
-
static int __init log_buf_len_setup(char *str)
{
unsigned long size = memparse(str, &str);
size = roundup_pow_of_two(size);
if (size > log_buf_len) {
unsigned long start, dest_idx, offset;
- char * new_log_buf;
+ char *new_log_buf;
new_log_buf = alloc_bootmem(size);
if (!new_log_buf) {
- printk("log_buf_len: allocation failed\n");
+ printk(KERN_WARNING "log_buf_len: allocation failed\n");
goto out;
}
log_end -= offset;
spin_unlock_irqrestore(&logbuf_lock, flags);
- printk("log_buf_len: %d\n", log_buf_len);
+ printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
}
out:
-
return 1;
}
* 9 -- Return number of unread characters in the log buffer
* 10 -- Return size of the log buffer
*/
-int do_syslog(int type, char __user * buf, int len)
+int do_syslog(int type, char __user *buf, int len)
{
unsigned long i, j, limit, count;
int do_clear = 0;
error = -EFAULT;
goto out;
}
- error = wait_event_interruptible(log_wait, (log_start - log_end));
+ error = wait_event_interruptible(log_wait,
+ (log_start - log_end));
if (error)
goto out;
i = 0;
error = i;
break;
case 4: /* Read/clear last kernel messages */
- do_clear = 1;
+ do_clear = 1;
/* FALL THRU */
case 3: /* Read last kernel messages */
error = -EINVAL;
limit = log_end;
/*
* __put_user() could sleep, and while we sleep
- * printk() could overwrite the messages
+ * printk() could overwrite the messages
* we try to copy to user space. Therefore
* the messages are copied in reverse. <manfreds>
*/
- for(i = 0; i < count && !error; i++) {
+ for (i = 0; i < count && !error; i++) {
j = limit-1-i;
if (j + log_buf_len < log_end)
break;
if (error)
break;
error = i;
- if(i != count) {
+ if (i != count) {
int offset = count-error;
/* buffer overflow during copy, correct user buffer. */
- for(i=0;i<error;i++) {
+ for (i = 0; i < error; i++) {
if (__get_user(c,&buf[i+offset]) ||
__put_user(c,&buf[i])) {
error = -EFAULT;
return error;
}
-asmlinkage long sys_syslog(int type, char __user * buf, int len)
+asmlinkage long sys_syslog(int type, char __user *buf, int len)
{
return do_syslog(type, buf, len);
}
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);
}
}
+static int __read_mostly ignore_loglevel;
+
+static int __init ignore_loglevel_setup(char *str)
+{
+ ignore_loglevel = 1;
+ printk(KERN_INFO "debug: ignoring loglevel setting.\n");
+
+ return 1;
+}
+
+__setup("ignore_loglevel", ignore_loglevel_setup);
+
/*
* Write out chars from start to end - 1 inclusive
*/
static void _call_console_drivers(unsigned long start,
unsigned long end, int msg_log_level)
{
- if (msg_log_level < console_loglevel &&
+ if ((msg_log_level < console_loglevel || ignore_loglevel) &&
console_drivers && start != end) {
if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
/* wrapped write */
unsigned long cur_index, start_print;
static int msg_level = -1;
- if (((long)(start - end)) > 0)
- BUG();
+ BUG_ON(((long)(start - end)) > 0);
cur_index = start;
start_print = start;
while (cur_index != end) {
- if ( msg_level < 0 &&
- ((end - cur_index) > 2) &&
- LOG_BUF(cur_index + 0) == '<' &&
- LOG_BUF(cur_index + 1) >= '0' &&
- LOG_BUF(cur_index + 1) <= '7' &&
- LOG_BUF(cur_index + 2) == '>')
- {
+ if (msg_level < 0 && ((end - cur_index) > 2) &&
+ LOG_BUF(cur_index + 0) == '<' &&
+ LOG_BUF(cur_index + 1) >= '0' &&
+ LOG_BUF(cur_index + 1) <= '7' &&
+ LOG_BUF(cur_index + 2) == '>') {
msg_level = LOG_BUF(cur_index + 1) - '0';
cur_index += 3;
start_print = cur_index;
}
while (cur_index != end) {
char c = LOG_BUF(cur_index);
- cur_index++;
+ cur_index++;
if (c == '\n') {
if (msg_level < 0) {
/*
static unsigned long oops_timestamp;
if (time_after_eq(jiffies, oops_timestamp) &&
- !time_after(jiffies, oops_timestamp + 30*HZ))
+ !time_after(jiffies, oops_timestamp + 30 * HZ))
return;
oops_timestamp = jiffies;
#else
static int printk_time = 0;
#endif
+module_param(printk_time, int, S_IRUGO | S_IWUSR);
static int __init printk_time_setup(char *str)
{
__setup("time", printk_time_setup);
-/*
- * This is printk. It can be called from any context. We want it to work.
- *
+__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
+ *
+ * This is printk(). It can be called from any context. We want it to work.
+ *
* 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
* into the log buffer and return. The current holder of the console_sem will
* One effect of this deferred printing is that code which calls printk() and
* then changes console_loglevel may break. This is because console_loglevel
* is inspected when the actual printing occurs.
+ *
+ * See also:
+ * printf(3)
*/
asmlinkage int printk(const char *fmt, ...)
return r;
}
+/* cpu currently holding logbuf_lock */
+static volatile unsigned int printk_cpu = UINT_MAX;
+
asmlinkage int vprintk(const char *fmt, va_list args)
{
unsigned long flags;
static char printk_buf[1024];
static int log_level_unknown = 1;
- if (unlikely(oops_in_progress))
+ 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 */
- spin_lock_irqsave(&logbuf_lock, flags);
+ 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);
p[1] <= '7' && p[2] == '>') {
loglev_char = p[1];
p += 3;
- printed_len += 3;
+ printed_len -= 3;
} else {
loglev_char = default_message_loglevel
+ '0';
}
- t = sched_clock();
+ t = printk_clock();
nanosec_rem = do_div(t, 1000000000);
tlen = sprintf(tbuf,
"<%c>[%5lu.%06lu] ",
for (tp = tbuf; tp < tbuf + tlen; tp++)
emit_log_char(*tp);
- printed_len += tlen - 3;
+ printed_len += tlen;
} else {
if (p[0] != '<' || p[1] < '0' ||
p[1] > '7' || p[2] != '>') {
emit_log_char(default_message_loglevel
+ '0');
emit_log_char('>');
+ printed_len += 3;
}
- printed_len += 3;
}
log_level_unknown = 0;
if (!*p)
log_level_unknown = 1;
}
- if (!cpu_online(smp_processor_id()) &&
- system_state != SYSTEM_RUNNING) {
+ 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 ...
*/
- 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.
*/
- 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();
+ 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.
*/
- spin_unlock_irqrestore(&logbuf_lock, flags);
+ printk_cpu = UINT_MAX;
+ spin_unlock(&logbuf_lock);
+ lockdep_on();
+ raw_local_irq_restore(flags);
}
-out:
+
+ preempt_enable();
return printed_len;
}
EXPORT_SYMBOL(printk);
#else
-asmlinkage long sys_syslog(int type, char __user * buf, int len)
+asmlinkage long sys_syslog(int type, char __user *buf, int len)
{
- return 0;
+ return -ENOSYS;
}
-int do_syslog(int type, char __user * buf, int len) { return 0; }
-static void call_console_drivers(unsigned long start, unsigned long end) {}
+static void call_console_drivers(unsigned long start, unsigned long end)
+{
+}
+
+#endif
+
+/*
+ * Set up a list of consoles. Called from init/main.c
+ */
+static int __init console_setup(char *str)
+{
+ char name[sizeof(console_cmdline[0].name)];
+ char *s, *options;
+ int idx;
+ /*
+ * Decode str into name, index, options.
+ */
+ if (str[0] >= '0' && str[0] <= '9') {
+ strcpy(name, "ttyS");
+ strncpy(name + 4, str, sizeof(name) - 5);
+ } else {
+ strncpy(name, str, sizeof(name) - 1);
+ }
+ name[sizeof(name) - 1] = 0;
+ if ((options = strchr(str, ',')) != NULL)
+ *(options++) = 0;
+#ifdef __sparc__
+ if (!strcmp(str, "ttya"))
+ strcpy(name, "ttyS0");
+ if (!strcmp(str, "ttyb"))
+ strcpy(name, "ttyS1");
#endif
+ for (s = name; *s; s++)
+ if ((*s >= '0' && *s <= '9') || *s == ',')
+ break;
+ idx = simple_strtoul(s, NULL, 10);
+ *s = 0;
+
+ add_preferred_console(name, idx, options);
+ return 1;
+}
+__setup("console=", console_setup);
/**
* add_preferred_console - add a device to the list of preferred consoles.
+ * @name: device name
+ * @idx: device index
+ * @options: options for this console
*
* The last preferred console added will be used for kernel messages
* and stdin/out/err for init. Normally this is used by console_setup
return 0;
}
+#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND
+/**
+ * suspend_console - suspend the console subsystem
+ *
+ * This disables printk() while we go into suspend states
+ */
+void suspend_console(void)
+{
+ printk("Suspending console(s)\n");
+ acquire_console_sem();
+ console_suspended = 1;
+}
+
+void resume_console(void)
+{
+ console_suspended = 0;
+ release_console_sem();
+}
+#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */
+
/**
* acquire_console_sem - lock the console system for exclusive use.
*
*/
void acquire_console_sem(void)
{
- if (in_interrupt())
- BUG();
+ BUG_ON(in_interrupt());
+ if (console_suspended) {
+ down(&secondary_console_sem);
+ return;
+ }
down(&console_sem);
console_locked = 1;
console_may_schedule = 1;
{
return console_locked;
}
-EXPORT_SYMBOL(is_console_locked);
+
+void wake_up_klogd(void)
+{
+ if (!oops_in_progress && waitqueue_active(&log_wait))
+ wake_up_interruptible(&log_wait);
+}
/**
* release_console_sem - unlock the console system
unsigned long _con_start, _log_end;
unsigned long wake_klogd = 0;
+ if (console_suspended) {
+ up(&secondary_console_sem);
+ 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)
+ wake_up_klogd();
}
EXPORT_SYMBOL(release_console_sem);
-/** console_conditional_schedule - yield the CPU if required
+/**
+ * console_conditional_schedule - yield the CPU if required
*
* If the console code is currently allowed to sleep, and
* if this CPU should yield the CPU to another task, do
c->unblank();
release_console_sem();
}
-EXPORT_SYMBOL(console_unblank);
/*
* Return the console tty driver structure and its associated index
* print any messages that were printed by the kernel before the
* console driver was initialized.
*/
-void register_console(struct console * console)
+void register_console(struct console *console)
{
- int i;
+ int i;
unsigned long flags;
+ struct console *bootconsole = NULL;
+
+ if (console_drivers) {
+ if (console->flags & CON_BOOT)
+ return;
+ if (console_drivers->flags & CON_BOOT)
+ bootconsole = console_drivers;
+ }
- if (preferred_console < 0)
+ if (preferred_console < 0 || bootconsole || !console_drivers)
preferred_console = selected_console;
/*
* See if this console matches one we selected on
* the command line.
*/
- for(i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) {
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
+ i++) {
if (strcmp(console_cmdline[i].name, console->name) != 0)
continue;
if (console->index >= 0 &&
break;
console->flags |= CON_ENABLED;
console->index = console_cmdline[i].index;
- if (i == preferred_console)
+ if (i == selected_console) {
console->flags |= CON_CONSDEV;
+ preferred_console = selected_console;
+ }
break;
}
if (!(console->flags & CON_ENABLED))
return;
- if (console_drivers && (console_drivers->flags & CON_BOOT)) {
- unregister_console(console_drivers);
+ if (bootconsole) {
+ printk(KERN_INFO "console handover: boot [%s%d] -> real [%s%d]\n",
+ bootconsole->name, bootconsole->index,
+ console->name, console->index);
+ unregister_console(bootconsole);
console->flags &= ~CON_PRINTBUFFER;
}
if ((console->flags & CON_CONSDEV) || console_drivers == NULL) {
console->next = console_drivers;
console_drivers = console;
+ if (console->next)
+ console->next->flags &= ~CON_CONSDEV;
} else {
console->next = console_drivers->next;
console_drivers->next = console;
}
EXPORT_SYMBOL(register_console);
-int unregister_console(struct console * console)
+int unregister_console(struct console *console)
{
- struct console *a,*b;
+ struct console *a, *b;
int res = 1;
acquire_console_sem();
if (console_drivers == console) {
console_drivers=console->next;
res = 0;
- } else {
+ } else if (console_drivers) {
for (a=console_drivers->next, b=console_drivers ;
a; b=a, a=b->next) {
if (a == console) {
b->next = a->next;
res = 0;
break;
- }
+ }
}
}
-
- /* If last console is removed, we re-enable picking the first
- * one that gets registered. Without that, pmac early boot console
- * would prevent fbcon from taking over.
+
+ /*
+ * If this isn't the last console and it has CON_CONSDEV set, we
+ * need to set it on the next preferred console.
*/
- if (console_drivers == NULL)
- preferred_console = selected_console;
-
+ if (console_drivers != NULL && console->flags & CON_CONSDEV)
+ console_drivers->flags |= CON_CONSDEV;
release_console_sem();
return res;
/**
* 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
int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst)
{
static DEFINE_SPINLOCK(ratelimit_lock);
- static unsigned long toks = 10*5*HZ;
+ static unsigned long toks = 10 * 5 * HZ;
static unsigned long last_msg;
static int missed;
unsigned long flags;
toks = ratelimit_burst * ratelimit_jiffies;
if (toks >= ratelimit_jiffies) {
int lost = missed;
+
missed = 0;
toks -= ratelimit_jiffies;
spin_unlock_irqrestore(&ratelimit_lock, flags);
EXPORT_SYMBOL(__printk_ratelimit);
/* minimum time in jiffies between messages */
-int printk_ratelimit_jiffies = 5*HZ;
+int printk_ratelimit_jiffies = 5 * HZ;
/* number of messages we send before ratelimiting */
int printk_ratelimit_burst = 10;
printk_ratelimit_burst);
}
EXPORT_SYMBOL(printk_ratelimit);
+
+/**
+ * printk_timed_ratelimit - caller-controlled printk ratelimiting
+ * @caller_jiffies: pointer to caller's state
+ * @interval_msecs: minimum interval between prints
+ *
+ * printk_timed_ratelimit() returns true if more than @interval_msecs
+ * milliseconds have elapsed since the last time printk_timed_ratelimit()
+ * returned true.
+ */
+bool printk_timed_ratelimit(unsigned long *caller_jiffies,
+ unsigned int interval_msecs)
+{
+ if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) {
+ *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs);
+ return true;
+ }
+ return false;
+}
+EXPORT_SYMBOL(printk_timed_ratelimit);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff