* [PATCH 3/4] printk: Separate out console bits to console.[ch]
2012-05-14 16:54 ` [PATCH 1/4] printk: Move to separate directory for easier modification Joe Perches
@ 2012-05-14 16:54 ` Joe Perches
0 siblings, 0 replies; 7+ messages in thread
From: Joe Perches @ 2012-05-14 16:54 UTC (permalink / raw)
To: Kay Sievers, linux-kernel
Cc: Hiroshi DOYU, linux-tegra, Peter Zijlstra, Andrew Morton,
Ingo Molnar, Greg Kroah-Hartman, Linus Torvalds
Add some clarity to the printk subsystem by restructuring
the code a bit.
Move the console variables and functions to separate
code and header files.
Signed-off-by: Joe Perches <joe@perches.com>
---
kernel/printk/Makefile | 1 +
kernel/printk/console.c | 913 +++++++++++++++++++++++++++++++++++++++++++++++
kernel/printk/console.h | 11 +
kernel/printk/printk.c | 854 +-------------------------------------------
4 files changed, 936 insertions(+), 843 deletions(-)
create mode 100644 kernel/printk/console.c
create mode 100644 kernel/printk/console.h
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 2fc9fe7..28b7129 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,2 +1,3 @@
obj-y += printk.o
obj-y += log_buf.o
+obj-y += console.o
diff --git a/kernel/printk/console.c b/kernel/printk/console.c
new file mode 100644
index 0000000..82a5455
--- /dev/null
+++ b/kernel/printk/console.c
@@ -0,0 +1,913 @@
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#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/delay.h>
+#include <linux/smp.h>
+#include <linux/security.h>
+#include <linux/bootmem.h>
+#include <linux/memblock.h>
+#include <linux/syscalls.h>
+#include <linux/kexec.h>
+#include <linux/kdb.h>
+#include <linux/ratelimit.h>
+#include <linux/kmsg_dump.h>
+#include <linux/syslog.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+#include <linux/rculist.h>
+#include <linux/uaccess.h>
+
+#include "log_buf.h"
+#include "console.h"
+
+#include <trace/events/printk.h>
+
+extern volatile unsigned int printk_cpu;
+extern size_t log_prefix(const char *p, unsigned int *level, char *special);
+extern int __read_mostly keep_bootcon;
+
+/* We show everything that is MORE important than this.. */
+#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
+#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
+
+#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
+
+int console_printk[4] = {
+ DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
+ DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
+ MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */
+ DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
+};
+
+/*
+ * console_sem protects the console_drivers list, and also
+ * provides serialisation for access to the entire console
+ * driver system.
+ */
+DEFINE_SEMAPHORE(console_sem);
+
+struct console *console_drivers;
+EXPORT_SYMBOL_GPL(console_drivers);
+
+/*
+ * This is used for debugging the mess that is the VT code by
+ * keeping track if we have the console semaphore held. It's
+ * definitely not the perfect debug tool (we don't know if _WE_
+ * hold it are racing, but it helps tracking those weird code
+ * 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_suspended;
+
+static int saved_console_loglevel = -1;
+
+/*
+ * If exclusive_console is non-NULL then only this console is to be printed to.
+ */
+static struct console *exclusive_console;
+
+/*
+ * Array of consoles built from command line options (console=)
+ */
+struct console_cmdline
+{
+ char name[8]; /* Name of the driver */
+ int index; /* Minor dev. to use */
+ char *options; /* Options for the driver */
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ char *brl_options; /* Options for braille driver */
+#endif
+};
+
+#define MAX_CMDLINECONSOLES 8
+
+static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
+static int selected_console = -1;
+static int preferred_console = -1;
+int console_set_on_cmdline;
+EXPORT_SYMBOL(console_set_on_cmdline);
+
+/* Flag: console code may call schedule() */
+static int console_may_schedule;
+
+static bool __read_mostly ignore_loglevel;
+
+static int __init ignore_loglevel_setup(char *str)
+{
+ ignore_loglevel = 1;
+ printk(KERN_INFO "debug: ignoring loglevel setting\n");
+
+ return 0;
+}
+
+early_param("ignore_loglevel", ignore_loglevel_setup);
+module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(ignore_loglevel,
+ "ignore loglevel setting, print all kernel messages to the console");
+
+int console_do_syslog(int type, char __user *buf, int len, bool from_file)
+{
+ int error = 0;
+
+ switch (type) {
+ case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */
+ if (saved_console_loglevel == -1)
+ saved_console_loglevel = console_loglevel;
+ console_loglevel = minimum_console_loglevel;
+ break;
+ case SYSLOG_ACTION_CONSOLE_ON: /* Enable logging to console */
+ if (saved_console_loglevel != -1) {
+ console_loglevel = saved_console_loglevel;
+ saved_console_loglevel = -1;
+ }
+ break;
+ case SYSLOG_ACTION_CONSOLE_LEVEL: /* Set level of messages
+ * printed to console
+ */
+
+ error = -EINVAL;
+ if (len < 1 || len > 8)
+ goto out;
+ if (len < minimum_console_loglevel)
+ len = minimum_console_loglevel;
+ console_loglevel = len;
+ /* Implicitly re-enable logging to console */
+ saved_console_loglevel = -1;
+ error = 0;
+ break;
+ }
+out:
+ return error;
+}
+
+/*
+ * Call the console drivers on a range of log_buf
+ */
+static void __call_console_drivers(unsigned start, unsigned end)
+{
+ struct console *con;
+
+ for_each_console(con) {
+ if (exclusive_console && con != exclusive_console)
+ continue;
+ if ((con->flags & CON_ENABLED) && con->write &&
+ (cpu_online(smp_processor_id()) ||
+ (con->flags & CON_ANYTIME)))
+ con->write(con, &LOG_BUF(start), end - start);
+ }
+}
+
+/*
+ * Write out chars from start to end - 1 inclusive
+ */
+static void _call_console_drivers(unsigned start,
+ unsigned end, int msg_log_level)
+{
+ trace_console(&LOG_BUF(0), start, end, log_buf_len);
+
+ if ((msg_log_level < console_loglevel || ignore_loglevel) &&
+ console_drivers && start != end) {
+ if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
+ /* wrapped write */
+ __call_console_drivers(start & LOG_BUF_MASK,
+ log_buf_len);
+ __call_console_drivers(0, end & LOG_BUF_MASK);
+ } else {
+ __call_console_drivers(start, end);
+ }
+ }
+}
+
+/*
+ * Call the console drivers, asking them to write out
+ * log_buf[start] to log_buf[end - 1].
+ * The console_lock must be held.
+ */
+static void call_console_drivers(unsigned start, unsigned end)
+{
+ unsigned cur_index, start_print;
+ static int msg_level = -1;
+
+ BUG_ON(((int)(start - end)) > 0);
+
+ cur_index = start;
+ start_print = start;
+ while (cur_index != end) {
+ if (msg_level < 0 && ((end - cur_index) > 2)) {
+ /* strip log prefix */
+ cur_index += log_prefix(&LOG_BUF(cur_index), &msg_level,
+ NULL);
+ start_print = cur_index;
+ }
+ while (cur_index != end) {
+ char c = LOG_BUF(cur_index);
+
+ cur_index++;
+ if (c == '\n') {
+ if (msg_level < 0) {
+ /*
+ * printk() has already given us
+ * loglevel tags in the buffer.
+ * This code is here in case the
+ * log buffer has wrapped right round
+ * and scribbled on those tags
+ */
+ msg_level = default_message_loglevel;
+ }
+ _call_console_drivers(start_print, cur_index,
+ msg_level);
+ msg_level = -1;
+ start_print = cur_index;
+ break;
+ }
+ }
+ }
+ _call_console_drivers(start_print, end, msg_level);
+}
+
+/*
+ * Zap console related locks when oopsing. Only zap at most once
+ * every 10 seconds, to leave time for slow consoles to print a
+ * full oops.
+ */
+void console_zap_locks(void)
+{
+ static unsigned long oops_timestamp;
+
+ if (time_after_eq(jiffies, oops_timestamp) &&
+ !time_after(jiffies, oops_timestamp + 30 * HZ))
+ return;
+
+ oops_timestamp = jiffies;
+
+ debug_locks_off();
+ /* If a crash is occurring, make sure we can't deadlock */
+ raw_spin_lock_init(&logbuf_lock);
+ /* And make sure that we print immediately */
+ sema_init(&console_sem, 1);
+}
+
+/* Check if we have any console registered that can be called early in boot. */
+static int have_callable_console(void)
+{
+ struct console *con;
+
+ for_each_console(con)
+ if (con->flags & CON_ANYTIME)
+ return 1;
+
+ return 0;
+}
+
+/*
+ * 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();
+}
+
+/*
+ * Try to get console ownership to actually show the kernel
+ * messages from a 'printk'. Return true (and with the
+ * console_lock held, and 'console_locked' set) if it
+ * is successful, false otherwise.
+ *
+ * This gets called with the 'logbuf_lock' spinlock held and
+ * interrupts disabled. It should return with 'lockbuf_lock'
+ * released but interrupts still disabled.
+ */
+int console_trylock_for_printk(unsigned int cpu)
+ __releases(&logbuf_lock)
+{
+ int retval = 0, wake = 0;
+
+ if (console_trylock()) {
+ retval = 1;
+
+ /*
+ * If we can't use the console, we need to release
+ * the console semaphore by hand to avoid flushing
+ * the buffer. We need to hold the console semaphore
+ * in order to do this test safely.
+ */
+ if (!can_use_console(cpu)) {
+ console_locked = 0;
+ wake = 1;
+ retval = 0;
+ }
+ }
+ printk_cpu = UINT_MAX;
+ if (wake)
+ up(&console_sem);
+ raw_spin_unlock(&logbuf_lock);
+ return retval;
+}
+
+static int __add_preferred_console(char *name, int idx, char *options,
+ char *brl_options)
+{
+ struct console_cmdline *c;
+ int i;
+
+ /*
+ * See if this tty is not yet registered, and
+ * if we have a slot free.
+ */
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
+ if (strcmp(console_cmdline[i].name, name) == 0 &&
+ console_cmdline[i].index == idx) {
+ if (!brl_options)
+ selected_console = i;
+ return 0;
+ }
+ if (i == MAX_CMDLINECONSOLES)
+ return -E2BIG;
+ if (!brl_options)
+ selected_console = i;
+ c = &console_cmdline[i];
+ strlcpy(c->name, name, sizeof(c->name));
+ c->options = options;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ c->brl_options = brl_options;
+#endif
+ c->index = idx;
+ return 0;
+}
+/*
+ * Set up a list of consoles. Called from init/main.c
+ */
+static int __init console_setup(char *str)
+{
+ char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
+ char *s, *options, *brl_options = NULL;
+ int idx;
+
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (!memcmp(str, "brl,", 4)) {
+ brl_options = "";
+ str += 4;
+ } else if (!memcmp(str, "brl=", 4)) {
+ brl_options = str + 4;
+ str = strchr(brl_options, ',');
+ if (!str) {
+ printk(KERN_ERR "need port name after brl=\n");
+ return 1;
+ }
+ *(str++) = 0;
+ }
+#endif
+
+ /*
+ * Decode str into name, index, options.
+ */
+ if (str[0] >= '0' && str[0] <= '9') {
+ strcpy(buf, "ttyS");
+ strncpy(buf + 4, str, sizeof(buf) - 5);
+ } else {
+ strncpy(buf, str, sizeof(buf) - 1);
+ }
+ buf[sizeof(buf) - 1] = 0;
+ if ((options = strchr(str, ',')) != NULL)
+ *(options++) = 0;
+#ifdef __sparc__
+ if (!strcmp(str, "ttya"))
+ strcpy(buf, "ttyS0");
+ if (!strcmp(str, "ttyb"))
+ strcpy(buf, "ttyS1");
+#endif
+ for (s = buf; *s; s++)
+ if ((*s >= '0' && *s <= '9') || *s == ',')
+ break;
+ idx = simple_strtoul(s, NULL, 10);
+ *s = 0;
+
+ __add_preferred_console(buf, idx, options, brl_options);
+ console_set_on_cmdline = 1;
+ 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
+ * above to handle user-supplied console arguments; however it can also
+ * be used by arch-specific code either to override the user or more
+ * commonly to provide a default console (ie from PROM variables) when
+ * the user has not supplied one.
+ */
+int add_preferred_console(char *name, int idx, char *options)
+{
+ return __add_preferred_console(name, idx, options, NULL);
+}
+
+int update_console_cmdline(char *name, int idx, char *name_new, int idx_new,
+ char *options)
+{
+ struct console_cmdline *c;
+ int i;
+
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
+ if (strcmp(console_cmdline[i].name, name) == 0 &&
+ console_cmdline[i].index == idx) {
+ c = &console_cmdline[i];
+ strlcpy(c->name, name_new, sizeof(c->name));
+ c->name[sizeof(c->name) - 1] = 0;
+ c->options = options;
+ c->index = idx_new;
+ return i;
+ }
+ /* not found */
+ return -1;
+}
+
+bool console_suspend_enabled = 1;
+EXPORT_SYMBOL(console_suspend_enabled);
+
+static int __init console_suspend_disable(char *str)
+{
+ console_suspend_enabled = 0;
+ return 1;
+}
+__setup("no_console_suspend", console_suspend_disable);
+module_param_named(console_suspend, console_suspend_enabled,
+ bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(console_suspend,
+ "suspend console during suspend and hibernate operations");
+
+/**
+ * suspend_console - suspend the console subsystem
+ *
+ * This disables printk() while we go into suspend states
+ */
+void suspend_console(void)
+{
+ if (!console_suspend_enabled)
+ return;
+ printk("Suspending console(s) (use no_console_suspend to debug)\n");
+ console_lock();
+ console_suspended = 1;
+ up(&console_sem);
+}
+
+void resume_console(void)
+{
+ if (!console_suspend_enabled)
+ return;
+ down(&console_sem);
+ console_suspended = 0;
+ console_unlock();
+}
+
+/**
+ * console_cpu_notify - print deferred console messages after CPU hotplug
+ * @self: notifier struct
+ * @action: CPU hotplug event
+ * @hcpu: unused
+ *
+ * If printk() is called from a CPU that is not online yet, the messages
+ * will be spooled but will not show up on the console. This function is
+ * called when a new CPU comes online (or fails to come up), and ensures
+ * that any such output gets printed.
+ */
+int __cpuinit console_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_DEAD:
+ case CPU_DYING:
+ case CPU_DOWN_FAILED:
+ case CPU_UP_CANCELED:
+ console_lock();
+ console_unlock();
+ }
+ return NOTIFY_OK;
+}
+
+/**
+ * console_lock - lock the console system for exclusive use.
+ *
+ * Acquires a lock which guarantees that the caller has
+ * exclusive access to the console system and the console_drivers list.
+ *
+ * Can sleep, returns nothing.
+ */
+void console_lock(void)
+{
+ BUG_ON(in_interrupt());
+ down(&console_sem);
+ if (console_suspended)
+ return;
+ console_locked = 1;
+ console_may_schedule = 1;
+}
+EXPORT_SYMBOL(console_lock);
+
+/**
+ * console_trylock - try to lock the console system for exclusive use.
+ *
+ * Tried to acquire a lock which guarantees that the caller has
+ * exclusive access to the console system and the console_drivers list.
+ *
+ * returns 1 on success, and 0 on failure to acquire the lock.
+ */
+int console_trylock(void)
+{
+ if (down_trylock(&console_sem))
+ return 0;
+ if (console_suspended) {
+ up(&console_sem);
+ return 0;
+ }
+ console_locked = 1;
+ console_may_schedule = 0;
+ return 1;
+}
+EXPORT_SYMBOL(console_trylock);
+
+int is_console_locked(void)
+{
+ return console_locked;
+}
+
+/**
+ * console_unlock - unlock the console system
+ *
+ * Releases the console_lock which the caller holds on the console system
+ * and the console driver list.
+ *
+ * While the console_lock was held, console output may have been buffered
+ * by printk(). If this is the case, console_unlock(); emits
+ * the output prior to releasing the lock.
+ *
+ * If there is output waiting for klogd, we wake it up.
+ *
+ * console_unlock(); may be called from any context.
+ */
+void console_unlock(void)
+{
+ unsigned long flags;
+ unsigned _con_start, _log_end;
+ unsigned wake_klogd = 0, retry = 0;
+
+ if (console_suspended) {
+ up(&console_sem);
+ return;
+ }
+
+ console_may_schedule = 0;
+
+again:
+ for ( ; ; ) {
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ wake_klogd |= log_start - log_end;
+ if (con_start == log_end)
+ break; /* Nothing to print */
+ _con_start = con_start;
+ _log_end = log_end;
+ con_start = log_end; /* Flush */
+ raw_spin_unlock(&logbuf_lock);
+ stop_critical_timings(); /* don't trace print latency */
+ call_console_drivers(_con_start, _log_end);
+ start_critical_timings();
+ local_irq_restore(flags);
+ }
+ console_locked = 0;
+
+ /* Release the exclusive_console once it is used */
+ if (unlikely(exclusive_console))
+ exclusive_console = NULL;
+
+ raw_spin_unlock(&logbuf_lock);
+
+ up(&console_sem);
+
+ /*
+ * Someone could have filled up the buffer again, so re-check if there's
+ * something to flush. In case we cannot trylock the console_sem again,
+ * there's a new owner and the console_unlock() from them will do the
+ * flush, no worries.
+ */
+ raw_spin_lock(&logbuf_lock);
+ if (con_start != log_end)
+ retry = 1;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ if (retry && console_trylock())
+ goto again;
+
+ if (wake_klogd)
+ wake_up_klogd();
+}
+EXPORT_SYMBOL(console_unlock);
+
+/**
+ * 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
+ * so here.
+ *
+ * Must be called within console_lock();.
+ */
+void __sched console_conditional_schedule(void)
+{
+ if (console_may_schedule)
+ cond_resched();
+}
+EXPORT_SYMBOL(console_conditional_schedule);
+
+void console_unblank(void)
+{
+ struct console *c;
+
+ /*
+ * console_unblank can no longer be called in interrupt context unless
+ * oops_in_progress is set to 1..
+ */
+ if (oops_in_progress) {
+ if (down_trylock(&console_sem) != 0)
+ return;
+ } else
+ console_lock();
+
+ console_locked = 1;
+ console_may_schedule = 0;
+ for_each_console(c)
+ if ((c->flags & CON_ENABLED) && c->unblank)
+ c->unblank();
+ console_unlock();
+}
+
+/*
+ * Return the console tty driver structure and its associated index
+ */
+struct tty_driver *console_device(int *index)
+{
+ struct console *c;
+ struct tty_driver *driver = NULL;
+
+ console_lock();
+ for_each_console(c) {
+ if (!c->device)
+ continue;
+ driver = c->device(c, index);
+ if (driver)
+ break;
+ }
+ console_unlock();
+ return driver;
+}
+
+/*
+ * Prevent further output on the passed console device so that (for example)
+ * serial drivers can disable console output before suspending a port, and can
+ * re-enable output afterwards.
+ */
+void console_stop(struct console *console)
+{
+ console_lock();
+ console->flags &= ~CON_ENABLED;
+ console_unlock();
+}
+EXPORT_SYMBOL(console_stop);
+
+void console_start(struct console *console)
+{
+ console_lock();
+ console->flags |= CON_ENABLED;
+ console_unlock();
+}
+EXPORT_SYMBOL(console_start);
+
+/*
+ * The console driver calls this routine during kernel initialization
+ * to register the console printing procedure with printk() and to
+ * print any messages that were printed by the kernel before the
+ * console driver was initialized.
+ *
+ * This can happen pretty early during the boot process (because of
+ * early_printk) - sometimes before setup_arch() completes - be careful
+ * of what kernel features are used - they may not be initialised yet.
+ *
+ * There are two types of consoles - bootconsoles (early_printk) and
+ * "real" consoles (everything which is not a bootconsole) which are
+ * handled differently.
+ * - Any number of bootconsoles can be registered at any time.
+ * - As soon as a "real" console is registered, all bootconsoles
+ * will be unregistered automatically.
+ * - Once a "real" console is registered, any attempt to register a
+ * bootconsoles will be rejected
+ */
+void register_console(struct console *newcon)
+{
+ int i;
+ unsigned long flags;
+ struct console *bcon = NULL;
+
+ /*
+ * before we register a new CON_BOOT console, make sure we don't
+ * already have a valid console
+ */
+ if (console_drivers && newcon->flags & CON_BOOT) {
+ /* find the last or real console */
+ for_each_console(bcon) {
+ if (!(bcon->flags & CON_BOOT)) {
+ printk(KERN_INFO "Too late to register bootconsole %s%d\n",
+ newcon->name, newcon->index);
+ return;
+ }
+ }
+ }
+
+ if (console_drivers && console_drivers->flags & CON_BOOT)
+ bcon = console_drivers;
+
+ if (preferred_console < 0 || bcon || !console_drivers)
+ preferred_console = selected_console;
+
+ if (newcon->early_setup)
+ newcon->early_setup();
+
+ /*
+ * See if we want to use this console driver. If we
+ * didn't select a console we take the first one
+ * that registers here.
+ */
+ if (preferred_console < 0) {
+ if (newcon->index < 0)
+ newcon->index = 0;
+ if (newcon->setup == NULL ||
+ newcon->setup(newcon, NULL) == 0) {
+ newcon->flags |= CON_ENABLED;
+ if (newcon->device) {
+ newcon->flags |= CON_CONSDEV;
+ preferred_console = 0;
+ }
+ }
+ }
+
+ /*
+ * See if this console matches one we selected on
+ * the command line.
+ */
+ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
+ i++) {
+ if (strcmp(console_cmdline[i].name, newcon->name) != 0)
+ continue;
+ if (newcon->index >= 0 &&
+ newcon->index != console_cmdline[i].index)
+ continue;
+ if (newcon->index < 0)
+ newcon->index = console_cmdline[i].index;
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (console_cmdline[i].brl_options) {
+ newcon->flags |= CON_BRL;
+ braille_register_console(newcon,
+ console_cmdline[i].index,
+ console_cmdline[i].options,
+ console_cmdline[i].brl_options);
+ return;
+ }
+#endif
+ if (newcon->setup &&
+ newcon->setup(newcon, console_cmdline[i].options) != 0)
+ break;
+ newcon->flags |= CON_ENABLED;
+ newcon->index = console_cmdline[i].index;
+ if (i == selected_console) {
+ newcon->flags |= CON_CONSDEV;
+ preferred_console = selected_console;
+ }
+ break;
+ }
+
+ if (!(newcon->flags & CON_ENABLED))
+ return;
+
+ /*
+ * If we have a bootconsole, and are switching to a real console,
+ * don't print everything out again, since when the boot console, and
+ * the real console are the same physical device, it's annoying to
+ * see the beginning boot messages twice
+ */
+ if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
+ newcon->flags &= ~CON_PRINTBUFFER;
+
+ /*
+ * Put this console in the list - keep the
+ * preferred driver at the head of the list.
+ */
+ console_lock();
+ if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
+ newcon->next = console_drivers;
+ console_drivers = newcon;
+ if (newcon->next)
+ newcon->next->flags &= ~CON_CONSDEV;
+ } else {
+ newcon->next = console_drivers->next;
+ console_drivers->next = newcon;
+ }
+ if (newcon->flags & CON_PRINTBUFFER) {
+ /*
+ * console_unlock(); will print out the buffered messages
+ * for us.
+ */
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ con_start = log_start;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ /*
+ * We're about to replay the log buffer. Only do this to the
+ * just-registered console to avoid excessive message spam to
+ * the already-registered consoles.
+ */
+ exclusive_console = newcon;
+ }
+ console_unlock();
+ console_sysfs_notify();
+
+ /*
+ * By unregistering the bootconsoles after we enable the real console
+ * we get the "console xxx enabled" message on all the consoles -
+ * boot consoles, real consoles, etc - this is to ensure that end
+ * users know there might be something in the kernel's log buffer that
+ * went to the bootconsole (that they do not see on the real console)
+ */
+ if (bcon &&
+ ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
+ !keep_bootcon) {
+ /* we need to iterate through twice, to make sure we print
+ * everything out, before we unregister the console(s)
+ */
+ printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n",
+ newcon->name, newcon->index);
+ for_each_console(bcon)
+ if (bcon->flags & CON_BOOT)
+ unregister_console(bcon);
+ } else {
+ printk(KERN_INFO "%sconsole [%s%d] enabled\n",
+ (newcon->flags & CON_BOOT) ? "boot" : "" ,
+ newcon->name, newcon->index);
+ }
+}
+EXPORT_SYMBOL(register_console);
+
+int unregister_console(struct console *console)
+{
+ struct console *a, *b;
+ int res = 1;
+
+#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
+ if (console->flags & CON_BRL)
+ return braille_unregister_console(console);
+#endif
+
+ console_lock();
+ if (console_drivers == console) {
+ console_drivers=console->next;
+ res = 0;
+ } 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 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 && console->flags & CON_CONSDEV)
+ console_drivers->flags |= CON_CONSDEV;
+
+ console_unlock();
+ console_sysfs_notify();
+ return res;
+}
+EXPORT_SYMBOL(unregister_console);
+
diff --git a/kernel/printk/console.h b/kernel/printk/console.h
new file mode 100644
index 0000000..7e15f6f
--- /dev/null
+++ b/kernel/printk/console.h
@@ -0,0 +1,11 @@
+#ifndef PRINTK_CONSOLE_H
+#define PRINTK_CONSOLE_H
+
+int console_do_syslog(int type, char __user *buf, int len, bool from_file);
+void console_zap_locks(void);
+int console_trylock_for_printk(unsigned int cpu)
+ __releases(&logbuf_lock);
+int __cpuinit console_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu);
+
+#endif
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index e90818a..3281441 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -37,6 +37,8 @@
#include <asm/uaccess.h>
+#include "console.h"
+
#define CREATE_TRACE_POINTS
#include <trace/events/printk.h>
@@ -50,17 +52,6 @@ void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
/* printk's without a loglevel use this.. */
#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
-/* We show everything that is MORE important than this.. */
-#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
-#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
-
-int console_printk[4] = {
- DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
- DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
- MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */
- DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
-};
-
/*
* Low level drivers may need that to know if they can schedule in
* their unblank() callback or not. So let's export it.
@@ -68,61 +59,10 @@ int console_printk[4] = {
int oops_in_progress;
EXPORT_SYMBOL(oops_in_progress);
-/*
- * console_sem protects the console_drivers list, and also
- * provides serialisation for access to the entire console
- * driver system.
- */
-DEFINE_SEMAPHORE(console_sem);
-
-struct console *console_drivers;
-EXPORT_SYMBOL_GPL(console_drivers);
-
-/*
- * This is used for debugging the mess that is the VT code by
- * keeping track if we have the console semaphore held. It's
- * definitely not the perfect debug tool (we don't know if _WE_
- * hold it are racing, but it helps tracking those weird code
- * path in the console code where we end up in places I want
- * locked without the console sempahore held
- */
-static int console_locked, console_suspended;
-
-/*
- * If exclusive_console is non-NULL then only this console is to be printed to.
- */
-static struct console *exclusive_console;
-
-/*
- * Array of consoles built from command line options (console=)
- */
-struct console_cmdline
-{
- char name[8]; /* Name of the driver */
- int index; /* Minor dev. to use */
- char *options; /* Options for the driver */
-#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
- char *brl_options; /* Options for braille driver */
-#endif
-};
-
-#define MAX_CMDLINECONSOLES 8
-
-static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
-static int selected_console = -1;
-static int preferred_console = -1;
-int console_set_on_cmdline;
-EXPORT_SYMBOL(console_set_on_cmdline);
-
-/* Flag: console code may call schedule() */
-static int console_may_schedule;
-
#ifdef CONFIG_PRINTK
#include "log_buf.h"
-static int saved_console_loglevel = -1;
-
#ifdef CONFIG_BOOT_PRINTK_DELAY
static int boot_delay; /* msecs delay after each printk during bootup */
@@ -242,30 +182,13 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
error = log_buf_do_syslog(type, buf, len, from_file);
break;
- /* Disable logging to console */
- case SYSLOG_ACTION_CONSOLE_OFF:
- if (saved_console_loglevel == -1)
- saved_console_loglevel = console_loglevel;
- console_loglevel = minimum_console_loglevel;
- break;
- /* Enable logging to console */
- case SYSLOG_ACTION_CONSOLE_ON:
- if (saved_console_loglevel != -1) {
- console_loglevel = saved_console_loglevel;
- saved_console_loglevel = -1;
- }
- break;
- /* Set level of messages printed to console */
+ case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */
+ case SYSLOG_ACTION_CONSOLE_ON: /* Enable logging to console */
case SYSLOG_ACTION_CONSOLE_LEVEL:
- error = -EINVAL;
- if (len < 1 || len > 8)
- goto out;
- if (len < minimum_console_loglevel)
- len = minimum_console_loglevel;
- console_loglevel = len;
- /* Implicitly re-enable logging to console */
- saved_console_loglevel = -1;
- error = 0;
+ /* Set level of messages
+ * printed to console
+ */
+ error = console_do_syslog(type, buf, len, from_file);
break;
default:
error = -EINVAL;
@@ -297,59 +220,6 @@ void kdb_syslog_data(char *syslog_data[4])
#endif /* CONFIG_KGDB_KDB */
/*
- * Call the console drivers on a range of log_buf
- */
-static void __call_console_drivers(unsigned start, unsigned end)
-{
- struct console *con;
-
- for_each_console(con) {
- if (exclusive_console && con != exclusive_console)
- continue;
- 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 bool __read_mostly ignore_loglevel;
-
-static int __init ignore_loglevel_setup(char *str)
-{
- ignore_loglevel = 1;
- printk(KERN_INFO "debug: ignoring loglevel setting.\n");
-
- return 0;
-}
-
-early_param("ignore_loglevel", ignore_loglevel_setup);
-module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
- "print all kernel messages to the console.");
-
-/*
- * Write out chars from start to end - 1 inclusive
- */
-static void _call_console_drivers(unsigned start,
- unsigned end, int msg_log_level)
-{
- trace_console(&LOG_BUF(0), start, end, log_buf_len);
-
- if ((msg_log_level < console_loglevel || ignore_loglevel) &&
- console_drivers && start != end) {
- if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
- /* wrapped write */
- __call_console_drivers(start & LOG_BUF_MASK,
- log_buf_len);
- __call_console_drivers(0, end & LOG_BUF_MASK);
- } else {
- __call_console_drivers(start, end);
- }
- }
-}
-
-/*
* Parse the syslog header <[0-9]*>. The decimal value represents 32bit, the
* lower 3 bit are the log level, the rest are the log facility. In case
* userspace passes usual userspace syslog messages to /dev/kmsg or
@@ -363,7 +233,7 @@ static void _call_console_drivers(unsigned start,
* and returned. If no valid header is found, 0 is returned and the passed
* variables are not touched.
*/
-static size_t log_prefix(const char *p, unsigned int *level, char *special)
+size_t log_prefix(const char *p, unsigned int *level, char *special)
{
unsigned int lev = 0;
char sp = '\0';
@@ -411,50 +281,6 @@ static size_t log_prefix(const char *p, unsigned int *level, char *special)
return len;
}
-/*
- * Call the console drivers, asking them to write out
- * log_buf[start] to log_buf[end - 1].
- * The console_lock must be held.
- */
-static void call_console_drivers(unsigned start, unsigned end)
-{
- unsigned cur_index, start_print;
- static int msg_level = -1;
-
- BUG_ON(((int)(start - end)) > 0);
-
- cur_index = start;
- start_print = start;
- while (cur_index != end) {
- if (msg_level < 0 && ((end - cur_index) > 2)) {
- /* strip log prefix */
- cur_index += log_prefix(&LOG_BUF(cur_index), &msg_level, NULL);
- start_print = cur_index;
- }
- while (cur_index != end) {
- char c = LOG_BUF(cur_index);
-
- cur_index++;
- if (c == '\n') {
- if (msg_level < 0) {
- /*
- * printk() has already given us loglevel tags in
- * the buffer. This code is here in case the
- * log buffer has wrapped right round and scribbled
- * on those tags
- */
- msg_level = default_message_loglevel;
- }
- _call_console_drivers(start_print, cur_index, msg_level);
- msg_level = -1;
- start_print = cur_index;
- break;
- }
- }
- }
- _call_console_drivers(start_print, end, msg_level);
-}
-
#if defined(CONFIG_PRINTK_TIME)
static bool printk_time = 1;
#else
@@ -465,18 +291,6 @@ module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
static bool always_kmsg_dump;
module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
-/* Check if we have any console registered that can be called early in boot. */
-static int have_callable_console(void)
-{
- struct console *con;
-
- for_each_console(con)
- if (con->flags & CON_ANYTIME)
- return 1;
-
- return 0;
-}
-
/**
* printk - print a kernel message
* @fmt: format string
@@ -520,57 +334,8 @@ asmlinkage int printk(const char *fmt, ...)
}
/* cpu currently holding logbuf_lock */
-static volatile unsigned int printk_cpu = UINT_MAX;
-
-/*
- * 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();
-}
-
-/*
- * Try to get console ownership to actually show the kernel
- * messages from a 'printk'. Return true (and with the
- * console_lock held, and 'console_locked' set) if it
- * is successful, false otherwise.
- *
- * This gets called with the 'logbuf_lock' spinlock held and
- * interrupts disabled. It should return with 'lockbuf_lock'
- * released but interrupts still disabled.
- */
-static int console_trylock_for_printk(unsigned int cpu)
- __releases(&logbuf_lock)
-{
- int retval = 0, wake = 0;
-
- if (console_trylock()) {
- retval = 1;
+volatile unsigned int printk_cpu = UINT_MAX;
- /*
- * If we can't use the console, we need to release
- * the console semaphore by hand to avoid flushing
- * the buffer. We need to hold the console semaphore
- * in order to do this test safely.
- */
- if (!can_use_console(cpu)) {
- console_locked = 0;
- wake = 1;
- retval = 0;
- }
- }
- printk_cpu = UINT_MAX;
- if (wake)
- up(&console_sem);
- raw_spin_unlock(&logbuf_lock);
- return retval;
-}
static const char recursion_bug_msg [] =
KERN_CRIT "BUG: recent printk recursion!\n";
static int recursion_bug;
@@ -732,245 +497,8 @@ out_restore_irqs:
EXPORT_SYMBOL(printk);
EXPORT_SYMBOL(vprintk);
-#else
-
-static void call_console_drivers(unsigned start, unsigned end)
-{
-}
-
#endif
-static int __add_preferred_console(char *name, int idx, char *options,
- char *brl_options)
-{
- struct console_cmdline *c;
- int i;
-
- /*
- * See if this tty is not yet registered, and
- * if we have a slot free.
- */
- for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
- if (strcmp(console_cmdline[i].name, name) == 0 &&
- console_cmdline[i].index == idx) {
- if (!brl_options)
- selected_console = i;
- return 0;
- }
- if (i == MAX_CMDLINECONSOLES)
- return -E2BIG;
- if (!brl_options)
- selected_console = i;
- c = &console_cmdline[i];
- strlcpy(c->name, name, sizeof(c->name));
- c->options = options;
-#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
- c->brl_options = brl_options;
-#endif
- c->index = idx;
- return 0;
-}
-/*
- * Set up a list of consoles. Called from init/main.c
- */
-static int __init console_setup(char *str)
-{
- char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
- char *s, *options, *brl_options = NULL;
- int idx;
-
-#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
- if (!memcmp(str, "brl,", 4)) {
- brl_options = "";
- str += 4;
- } else if (!memcmp(str, "brl=", 4)) {
- brl_options = str + 4;
- str = strchr(brl_options, ',');
- if (!str) {
- printk(KERN_ERR "need port name after brl=\n");
- return 1;
- }
- *(str++) = 0;
- }
-#endif
-
- /*
- * Decode str into name, index, options.
- */
- if (str[0] >= '0' && str[0] <= '9') {
- strcpy(buf, "ttyS");
- strncpy(buf + 4, str, sizeof(buf) - 5);
- } else {
- strncpy(buf, str, sizeof(buf) - 1);
- }
- buf[sizeof(buf) - 1] = 0;
- if ((options = strchr(str, ',')) != NULL)
- *(options++) = 0;
-#ifdef __sparc__
- if (!strcmp(str, "ttya"))
- strcpy(buf, "ttyS0");
- if (!strcmp(str, "ttyb"))
- strcpy(buf, "ttyS1");
-#endif
- for (s = buf; *s; s++)
- if ((*s >= '0' && *s <= '9') || *s == ',')
- break;
- idx = simple_strtoul(s, NULL, 10);
- *s = 0;
-
- __add_preferred_console(buf, idx, options, brl_options);
- console_set_on_cmdline = 1;
- 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
- * above to handle user-supplied console arguments; however it can also
- * be used by arch-specific code either to override the user or more
- * commonly to provide a default console (ie from PROM variables) when
- * the user has not supplied one.
- */
-int add_preferred_console(char *name, int idx, char *options)
-{
- return __add_preferred_console(name, idx, options, NULL);
-}
-
-int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
-{
- struct console_cmdline *c;
- int i;
-
- for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
- if (strcmp(console_cmdline[i].name, name) == 0 &&
- console_cmdline[i].index == idx) {
- c = &console_cmdline[i];
- strlcpy(c->name, name_new, sizeof(c->name));
- c->name[sizeof(c->name) - 1] = 0;
- c->options = options;
- c->index = idx_new;
- return i;
- }
- /* not found */
- return -1;
-}
-
-bool console_suspend_enabled = 1;
-EXPORT_SYMBOL(console_suspend_enabled);
-
-static int __init console_suspend_disable(char *str)
-{
- console_suspend_enabled = 0;
- return 1;
-}
-__setup("no_console_suspend", console_suspend_disable);
-module_param_named(console_suspend, console_suspend_enabled,
- bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
- " and hibernate operations");
-
-/**
- * suspend_console - suspend the console subsystem
- *
- * This disables printk() while we go into suspend states
- */
-void suspend_console(void)
-{
- if (!console_suspend_enabled)
- return;
- printk("Suspending console(s) (use no_console_suspend to debug)\n");
- console_lock();
- console_suspended = 1;
- up(&console_sem);
-}
-
-void resume_console(void)
-{
- if (!console_suspend_enabled)
- return;
- down(&console_sem);
- console_suspended = 0;
- console_unlock();
-}
-
-/**
- * console_cpu_notify - print deferred console messages after CPU hotplug
- * @self: notifier struct
- * @action: CPU hotplug event
- * @hcpu: unused
- *
- * If printk() is called from a CPU that is not online yet, the messages
- * will be spooled but will not show up on the console. This function is
- * called when a new CPU comes online (or fails to come up), and ensures
- * that any such output gets printed.
- */
-static int __cpuinit console_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- switch (action) {
- case CPU_ONLINE:
- case CPU_DEAD:
- case CPU_DYING:
- case CPU_DOWN_FAILED:
- case CPU_UP_CANCELED:
- console_lock();
- console_unlock();
- }
- return NOTIFY_OK;
-}
-
-/**
- * console_lock - lock the console system for exclusive use.
- *
- * Acquires a lock which guarantees that the caller has
- * exclusive access to the console system and the console_drivers list.
- *
- * Can sleep, returns nothing.
- */
-void console_lock(void)
-{
- BUG_ON(in_interrupt());
- down(&console_sem);
- if (console_suspended)
- return;
- console_locked = 1;
- console_may_schedule = 1;
-}
-EXPORT_SYMBOL(console_lock);
-
-/**
- * console_trylock - try to lock the console system for exclusive use.
- *
- * Tried to acquire a lock which guarantees that the caller has
- * exclusive access to the console system and the console_drivers list.
- *
- * returns 1 on success, and 0 on failure to acquire the lock.
- */
-int console_trylock(void)
-{
- if (down_trylock(&console_sem))
- return 0;
- if (console_suspended) {
- up(&console_sem);
- return 0;
- }
- console_locked = 1;
- console_may_schedule = 0;
- return 1;
-}
-EXPORT_SYMBOL(console_trylock);
-
-int is_console_locked(void)
-{
- return console_locked;
-}
-
/*
* Delayed printk facility, for scheduler-internal messages:
*/
@@ -1008,157 +536,7 @@ void wake_up_klogd(void)
this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
}
-/**
- * console_unlock - unlock the console system
- *
- * Releases the console_lock which the caller holds on the console system
- * and the console driver list.
- *
- * While the console_lock was held, console output may have been buffered
- * by printk(). If this is the case, console_unlock(); emits
- * the output prior to releasing the lock.
- *
- * If there is output waiting for klogd, we wake it up.
- *
- * console_unlock(); may be called from any context.
- */
-void console_unlock(void)
-{
- unsigned long flags;
- unsigned _con_start, _log_end;
- unsigned wake_klogd = 0, retry = 0;
-
- if (console_suspended) {
- up(&console_sem);
- return;
- }
-
- console_may_schedule = 0;
-
-again:
- for ( ; ; ) {
- raw_spin_lock_irqsave(&logbuf_lock, flags);
- wake_klogd |= log_start - log_end;
- if (con_start == log_end)
- break; /* Nothing to print */
- _con_start = con_start;
- _log_end = log_end;
- con_start = log_end; /* Flush */
- raw_spin_unlock(&logbuf_lock);
- stop_critical_timings(); /* don't trace print latency */
- call_console_drivers(_con_start, _log_end);
- start_critical_timings();
- local_irq_restore(flags);
- }
- console_locked = 0;
-
- /* Release the exclusive_console once it is used */
- if (unlikely(exclusive_console))
- exclusive_console = NULL;
-
- raw_spin_unlock(&logbuf_lock);
-
- up(&console_sem);
-
- /*
- * Someone could have filled up the buffer again, so re-check if there's
- * something to flush. In case we cannot trylock the console_sem again,
- * there's a new owner and the console_unlock() from them will do the
- * flush, no worries.
- */
- raw_spin_lock(&logbuf_lock);
- if (con_start != log_end)
- retry = 1;
- raw_spin_unlock_irqrestore(&logbuf_lock, flags);
-
- if (retry && console_trylock())
- goto again;
-
- if (wake_klogd)
- wake_up_klogd();
-}
-EXPORT_SYMBOL(console_unlock);
-
-/**
- * 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
- * so here.
- *
- * Must be called within console_lock();.
- */
-void __sched console_conditional_schedule(void)
-{
- if (console_may_schedule)
- cond_resched();
-}
-EXPORT_SYMBOL(console_conditional_schedule);
-
-void console_unblank(void)
-{
- struct console *c;
-
- /*
- * console_unblank can no longer be called in interrupt context unless
- * oops_in_progress is set to 1..
- */
- if (oops_in_progress) {
- if (down_trylock(&console_sem) != 0)
- return;
- } else
- console_lock();
-
- console_locked = 1;
- console_may_schedule = 0;
- for_each_console(c)
- if ((c->flags & CON_ENABLED) && c->unblank)
- c->unblank();
- console_unlock();
-}
-
-/*
- * Return the console tty driver structure and its associated index
- */
-struct tty_driver *console_device(int *index)
-{
- struct console *c;
- struct tty_driver *driver = NULL;
-
- console_lock();
- for_each_console(c) {
- if (!c->device)
- continue;
- driver = c->device(c, index);
- if (driver)
- break;
- }
- console_unlock();
- return driver;
-}
-
-/*
- * Prevent further output on the passed console device so that (for example)
- * serial drivers can disable console output before suspending a port, and can
- * re-enable output afterwards.
- */
-void console_stop(struct console *console)
-{
- console_lock();
- console->flags &= ~CON_ENABLED;
- console_unlock();
-}
-EXPORT_SYMBOL(console_stop);
-
-void console_start(struct console *console)
-{
- console_lock();
- console->flags |= CON_ENABLED;
- console_unlock();
-}
-EXPORT_SYMBOL(console_start);
-
-static int __read_mostly keep_bootcon;
+int __read_mostly keep_bootcon;
static int __init keep_bootcon_setup(char *str)
{
@@ -1170,216 +548,6 @@ static int __init keep_bootcon_setup(char *str)
early_param("keep_bootcon", keep_bootcon_setup);
-/*
- * The console driver calls this routine during kernel initialization
- * to register the console printing procedure with printk() and to
- * print any messages that were printed by the kernel before the
- * console driver was initialized.
- *
- * This can happen pretty early during the boot process (because of
- * early_printk) - sometimes before setup_arch() completes - be careful
- * of what kernel features are used - they may not be initialised yet.
- *
- * There are two types of consoles - bootconsoles (early_printk) and
- * "real" consoles (everything which is not a bootconsole) which are
- * handled differently.
- * - Any number of bootconsoles can be registered at any time.
- * - As soon as a "real" console is registered, all bootconsoles
- * will be unregistered automatically.
- * - Once a "real" console is registered, any attempt to register a
- * bootconsoles will be rejected
- */
-void register_console(struct console *newcon)
-{
- int i;
- unsigned long flags;
- struct console *bcon = NULL;
-
- /*
- * before we register a new CON_BOOT console, make sure we don't
- * already have a valid console
- */
- if (console_drivers && newcon->flags & CON_BOOT) {
- /* find the last or real console */
- for_each_console(bcon) {
- if (!(bcon->flags & CON_BOOT)) {
- printk(KERN_INFO "Too late to register bootconsole %s%d\n",
- newcon->name, newcon->index);
- return;
- }
- }
- }
-
- if (console_drivers && console_drivers->flags & CON_BOOT)
- bcon = console_drivers;
-
- if (preferred_console < 0 || bcon || !console_drivers)
- preferred_console = selected_console;
-
- if (newcon->early_setup)
- newcon->early_setup();
-
- /*
- * See if we want to use this console driver. If we
- * didn't select a console we take the first one
- * that registers here.
- */
- if (preferred_console < 0) {
- if (newcon->index < 0)
- newcon->index = 0;
- if (newcon->setup == NULL ||
- newcon->setup(newcon, NULL) == 0) {
- newcon->flags |= CON_ENABLED;
- if (newcon->device) {
- newcon->flags |= CON_CONSDEV;
- preferred_console = 0;
- }
- }
- }
-
- /*
- * See if this console matches one we selected on
- * the command line.
- */
- for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
- i++) {
- if (strcmp(console_cmdline[i].name, newcon->name) != 0)
- continue;
- if (newcon->index >= 0 &&
- newcon->index != console_cmdline[i].index)
- continue;
- if (newcon->index < 0)
- newcon->index = console_cmdline[i].index;
-#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
- if (console_cmdline[i].brl_options) {
- newcon->flags |= CON_BRL;
- braille_register_console(newcon,
- console_cmdline[i].index,
- console_cmdline[i].options,
- console_cmdline[i].brl_options);
- return;
- }
-#endif
- if (newcon->setup &&
- newcon->setup(newcon, console_cmdline[i].options) != 0)
- break;
- newcon->flags |= CON_ENABLED;
- newcon->index = console_cmdline[i].index;
- if (i == selected_console) {
- newcon->flags |= CON_CONSDEV;
- preferred_console = selected_console;
- }
- break;
- }
-
- if (!(newcon->flags & CON_ENABLED))
- return;
-
- /*
- * If we have a bootconsole, and are switching to a real console,
- * don't print everything out again, since when the boot console, and
- * the real console are the same physical device, it's annoying to
- * see the beginning boot messages twice
- */
- if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
- newcon->flags &= ~CON_PRINTBUFFER;
-
- /*
- * Put this console in the list - keep the
- * preferred driver at the head of the list.
- */
- console_lock();
- if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
- newcon->next = console_drivers;
- console_drivers = newcon;
- if (newcon->next)
- newcon->next->flags &= ~CON_CONSDEV;
- } else {
- newcon->next = console_drivers->next;
- console_drivers->next = newcon;
- }
- if (newcon->flags & CON_PRINTBUFFER) {
- /*
- * console_unlock(); will print out the buffered messages
- * for us.
- */
- raw_spin_lock_irqsave(&logbuf_lock, flags);
- con_start = log_start;
- raw_spin_unlock_irqrestore(&logbuf_lock, flags);
- /*
- * We're about to replay the log buffer. Only do this to the
- * just-registered console to avoid excessive message spam to
- * the already-registered consoles.
- */
- exclusive_console = newcon;
- }
- console_unlock();
- console_sysfs_notify();
-
- /*
- * By unregistering the bootconsoles after we enable the real console
- * we get the "console xxx enabled" message on all the consoles -
- * boot consoles, real consoles, etc - this is to ensure that end
- * users know there might be something in the kernel's log buffer that
- * went to the bootconsole (that they do not see on the real console)
- */
- if (bcon &&
- ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
- !keep_bootcon) {
- /* we need to iterate through twice, to make sure we print
- * everything out, before we unregister the console(s)
- */
- printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n",
- newcon->name, newcon->index);
- for_each_console(bcon)
- if (bcon->flags & CON_BOOT)
- unregister_console(bcon);
- } else {
- printk(KERN_INFO "%sconsole [%s%d] enabled\n",
- (newcon->flags & CON_BOOT) ? "boot" : "" ,
- newcon->name, newcon->index);
- }
-}
-EXPORT_SYMBOL(register_console);
-
-int unregister_console(struct console *console)
-{
- struct console *a, *b;
- int res = 1;
-
-#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
- if (console->flags & CON_BRL)
- return braille_unregister_console(console);
-#endif
-
- console_lock();
- if (console_drivers == console) {
- console_drivers=console->next;
- res = 0;
- } 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 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 && console->flags & CON_CONSDEV)
- console_drivers->flags |= CON_CONSDEV;
-
- console_unlock();
- console_sysfs_notify();
- return res;
-}
-EXPORT_SYMBOL(unregister_console);
-
static int __init printk_late_init(void)
{
struct console *con;
--
1.7.8.111.gad25c.dirty
^ permalink raw reply related [flat|nested] 7+ messages in thread