Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: printk: Fix "printk: Enable the use of more than one CON_BOOT (early console)" printk: Restore previous console_loglevel when re-enabling logging printk: Ensure that "console enabled" messages are printed on the console printk: Enable the use of more than one CON_BOOT (early console)
This commit is contained in:
Linus Torvalds
commit
53e16fbd30
175
kernel/printk.c
175
kernel/printk.c
@ -36,6 +36,12 @@
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#include <asm/uaccess.h>
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/*
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* for_each_console() allows you to iterate on each console
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*/
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#define for_each_console(con) \
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for (con = console_drivers; con != NULL; con = con->next)
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/*
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* Architectures can override it:
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*/
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@ -61,6 +67,8 @@ int console_printk[4] = {
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DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
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};
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static int saved_console_loglevel = -1;
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/*
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* Low level drivers may need that to know if they can schedule in
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* their unblank() callback or not. So let's export it.
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@ -372,10 +380,15 @@ int do_syslog(int type, char __user *buf, int len)
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logged_chars = 0;
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break;
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case 6: /* Disable logging to console */
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if (saved_console_loglevel == -1)
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saved_console_loglevel = console_loglevel;
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console_loglevel = minimum_console_loglevel;
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break;
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case 7: /* Enable logging to console */
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console_loglevel = default_console_loglevel;
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if (saved_console_loglevel != -1) {
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console_loglevel = saved_console_loglevel;
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saved_console_loglevel = -1;
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}
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break;
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case 8: /* Set level of messages printed to console */
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error = -EINVAL;
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@ -384,6 +397,8 @@ int do_syslog(int type, char __user *buf, int len)
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if (len < minimum_console_loglevel)
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len = minimum_console_loglevel;
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console_loglevel = len;
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/* Implicitly re-enable logging to console */
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saved_console_loglevel = -1;
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error = 0;
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break;
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case 9: /* Number of chars in the log buffer */
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@ -412,7 +427,7 @@ static void __call_console_drivers(unsigned start, unsigned end)
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{
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struct console *con;
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for (con = console_drivers; con; con = con->next) {
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for_each_console(con) {
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if ((con->flags & CON_ENABLED) && con->write &&
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(cpu_online(smp_processor_id()) ||
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(con->flags & CON_ANYTIME)))
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@ -544,7 +559,7 @@ static int have_callable_console(void)
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{
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struct console *con;
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for (con = console_drivers; con; con = con->next)
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for_each_console(con)
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if (con->flags & CON_ANYTIME)
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return 1;
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@ -1082,7 +1097,7 @@ void console_unblank(void)
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console_locked = 1;
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console_may_schedule = 0;
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for (c = console_drivers; c != NULL; c = c->next)
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for_each_console(c)
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if ((c->flags & CON_ENABLED) && c->unblank)
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c->unblank();
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release_console_sem();
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@ -1097,7 +1112,7 @@ struct tty_driver *console_device(int *index)
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struct tty_driver *driver = NULL;
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acquire_console_sem();
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for (c = console_drivers; c != NULL; c = c->next) {
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for_each_console(c) {
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if (!c->device)
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continue;
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driver = c->device(c, index);
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@ -1134,25 +1149,49 @@ EXPORT_SYMBOL(console_start);
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* to register the console printing procedure with printk() and to
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* print any messages that were printed by the kernel before the
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* console driver was initialized.
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*
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* This can happen pretty early during the boot process (because of
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* early_printk) - sometimes before setup_arch() completes - be careful
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* of what kernel features are used - they may not be initialised yet.
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*
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* There are two types of consoles - bootconsoles (early_printk) and
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* "real" consoles (everything which is not a bootconsole) which are
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* handled differently.
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* - Any number of bootconsoles can be registered at any time.
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* - As soon as a "real" console is registered, all bootconsoles
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* will be unregistered automatically.
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* - Once a "real" console is registered, any attempt to register a
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* bootconsoles will be rejected
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*/
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void register_console(struct console *console)
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void register_console(struct console *newcon)
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{
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int i;
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unsigned long flags;
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struct console *bootconsole = NULL;
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struct console *bcon = NULL;
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if (console_drivers) {
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if (console->flags & CON_BOOT)
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return;
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if (console_drivers->flags & CON_BOOT)
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bootconsole = console_drivers;
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/*
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* before we register a new CON_BOOT console, make sure we don't
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* already have a valid console
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*/
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if (console_drivers && newcon->flags & CON_BOOT) {
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/* find the last or real console */
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for_each_console(bcon) {
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if (!(bcon->flags & CON_BOOT)) {
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printk(KERN_INFO "Too late to register bootconsole %s%d\n",
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newcon->name, newcon->index);
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return;
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}
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}
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}
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if (preferred_console < 0 || bootconsole || !console_drivers)
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if (console_drivers && console_drivers->flags & CON_BOOT)
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bcon = console_drivers;
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if (preferred_console < 0 || bcon || !console_drivers)
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preferred_console = selected_console;
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if (console->early_setup)
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console->early_setup();
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if (newcon->early_setup)
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newcon->early_setup();
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/*
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* See if we want to use this console driver. If we
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@ -1160,13 +1199,13 @@ void register_console(struct console *console)
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* that registers here.
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*/
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if (preferred_console < 0) {
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if (console->index < 0)
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console->index = 0;
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if (console->setup == NULL ||
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console->setup(console, NULL) == 0) {
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console->flags |= CON_ENABLED;
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if (console->device) {
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console->flags |= CON_CONSDEV;
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if (newcon->index < 0)
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newcon->index = 0;
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if (newcon->setup == NULL ||
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newcon->setup(newcon, NULL) == 0) {
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newcon->flags |= CON_ENABLED;
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if (newcon->device) {
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newcon->flags |= CON_CONSDEV;
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preferred_console = 0;
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}
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}
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@ -1178,64 +1217,62 @@ void register_console(struct console *console)
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*/
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for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
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i++) {
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if (strcmp(console_cmdline[i].name, console->name) != 0)
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if (strcmp(console_cmdline[i].name, newcon->name) != 0)
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continue;
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if (console->index >= 0 &&
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console->index != console_cmdline[i].index)
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if (newcon->index >= 0 &&
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newcon->index != console_cmdline[i].index)
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continue;
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if (console->index < 0)
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console->index = console_cmdline[i].index;
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if (newcon->index < 0)
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newcon->index = console_cmdline[i].index;
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#ifdef CONFIG_A11Y_BRAILLE_CONSOLE
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if (console_cmdline[i].brl_options) {
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console->flags |= CON_BRL;
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braille_register_console(console,
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newcon->flags |= CON_BRL;
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braille_register_console(newcon,
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console_cmdline[i].index,
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console_cmdline[i].options,
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console_cmdline[i].brl_options);
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return;
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}
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#endif
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if (console->setup &&
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console->setup(console, console_cmdline[i].options) != 0)
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if (newcon->setup &&
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newcon->setup(newcon, console_cmdline[i].options) != 0)
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break;
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console->flags |= CON_ENABLED;
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console->index = console_cmdline[i].index;
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newcon->flags |= CON_ENABLED;
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newcon->index = console_cmdline[i].index;
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if (i == selected_console) {
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console->flags |= CON_CONSDEV;
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newcon->flags |= CON_CONSDEV;
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preferred_console = selected_console;
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}
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break;
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}
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if (!(console->flags & CON_ENABLED))
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if (!(newcon->flags & CON_ENABLED))
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return;
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if (bootconsole && (console->flags & CON_CONSDEV)) {
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printk(KERN_INFO "console handover: boot [%s%d] -> real [%s%d]\n",
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bootconsole->name, bootconsole->index,
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console->name, console->index);
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unregister_console(bootconsole);
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console->flags &= ~CON_PRINTBUFFER;
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} else {
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printk(KERN_INFO "console [%s%d] enabled\n",
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console->name, console->index);
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}
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/*
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* If we have a bootconsole, and are switching to a real console,
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* don't print everything out again, since when the boot console, and
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* the real console are the same physical device, it's annoying to
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* see the beginning boot messages twice
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*/
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if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
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newcon->flags &= ~CON_PRINTBUFFER;
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/*
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* Put this console in the list - keep the
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* preferred driver at the head of the list.
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*/
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acquire_console_sem();
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if ((console->flags & CON_CONSDEV) || console_drivers == NULL) {
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console->next = console_drivers;
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console_drivers = console;
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if (console->next)
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console->next->flags &= ~CON_CONSDEV;
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if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
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newcon->next = console_drivers;
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console_drivers = newcon;
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if (newcon->next)
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newcon->next->flags &= ~CON_CONSDEV;
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} else {
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console->next = console_drivers->next;
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console_drivers->next = console;
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newcon->next = console_drivers->next;
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console_drivers->next = newcon;
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}
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if (console->flags & CON_PRINTBUFFER) {
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if (newcon->flags & CON_PRINTBUFFER) {
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/*
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* release_console_sem() will print out the buffered messages
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* for us.
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@ -1245,6 +1282,28 @@ void register_console(struct console *console)
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spin_unlock_irqrestore(&logbuf_lock, flags);
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}
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release_console_sem();
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/*
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* By unregistering the bootconsoles after we enable the real console
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* we get the "console xxx enabled" message on all the consoles -
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* boot consoles, real consoles, etc - this is to ensure that end
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* users know there might be something in the kernel's log buffer that
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* went to the bootconsole (that they do not see on the real console)
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*/
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if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) {
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/* we need to iterate through twice, to make sure we print
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* everything out, before we unregister the console(s)
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*/
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printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n",
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newcon->name, newcon->index);
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for_each_console(bcon)
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if (bcon->flags & CON_BOOT)
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unregister_console(bcon);
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} else {
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printk(KERN_INFO "%sconsole [%s%d] enabled\n",
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(newcon->flags & CON_BOOT) ? "boot" : "" ,
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newcon->name, newcon->index);
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}
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}
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EXPORT_SYMBOL(register_console);
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@ -1287,11 +1346,13 @@ EXPORT_SYMBOL(unregister_console);
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static int __init disable_boot_consoles(void)
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{
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if (console_drivers != NULL) {
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if (console_drivers->flags & CON_BOOT) {
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struct console *con;
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for_each_console(con) {
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if (con->flags & CON_BOOT) {
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printk(KERN_INFO "turn off boot console %s%d\n",
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console_drivers->name, console_drivers->index);
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return unregister_console(console_drivers);
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con->name, con->index);
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unregister_console(con);
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}
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}
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return 0;
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