#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>
* 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);
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);
}
}
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;
#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
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 ...
*/
+ console_locked = 1;
printk_cpu = UINT_MAX;
spin_unlock_irqrestore(&logbuf_lock, flags);
- goto out;
- }
- if (!down_trylock(&console_sem)) {
- console_locked = 1;
+
/*
- * 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);
+ }
} else {
/*
* Someone else owns the drivers. We drop the spinlock, which
printk_cpu = UINT_MAX;
spin_unlock_irqrestore(&logbuf_lock, flags);
}
-out:
+
preempt_enable();
return printed_len;
}
#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
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;
projects / karo-tx-linux.git / blobdiff