* 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
+ * manfred@colorfullife.com
* Rewrote bits to get rid of console_lock
* 01Mar01 Andrew Morton <andrewm@uow.edu.au>
*/
* 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);
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;
return sched_clock();
}
-/*
+/**
+ * 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
* 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, ...)
p[1] <= '7' && p[2] == '>') {
loglev_char = p[1];
p += 3;
- printed_len += 3;
+ printed_len -= 3;
} else {
loglev_char = default_message_loglevel
+ '0';
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)
#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;
}
+/**
+ * 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)
{
- 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;
unsigned long _con_start, _log_end;
unsigned long wake_klogd = 0;
+ if (console_suspended) {
+ up(&secondary_console_sem);
+ return;
+ }
for ( ; ; ) {
spin_lock_irqsave(&logbuf_lock, flags);
wake_klogd |= log_start - log_end;
}
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
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) {
/**
* 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