X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=ddebdcc585b9c22e0eb09d69a9399236210eb18d;hb=5cd4d056da050eb96d88540ecfd51245a4e1cdf7;hp=cc443407660a8b5c3945d519af22b3fe6112849d;hpb=804f448fadfb16effa3f62acf9f171b0c774c306;p=linux-2.6.git diff --git a/kernel/printk.c b/kernel/printk.c index cc4434076..ddebdcc58 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -10,8 +10,8 @@ * 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 */ @@ -23,15 +23,18 @@ #include #include #include +#include +#include #include +#include #include /* For in_interrupt() */ -#include #include #include #include #include #include -#include +#include +#include #include @@ -53,7 +56,7 @@ int console_printk[4] = { DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ }; -EXPORT_SYMBOL(console_printk); +EXPORT_UNUSED_SYMBOL(console_printk); /* June 2006 */ /* * Low lever drivers may need that to know if they can schedule in @@ -68,6 +71,7 @@ EXPORT_SYMBOL(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 @@ -77,7 +81,7 @@ struct console *console_drivers; * 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 @@ -123,44 +127,6 @@ static char *log_buf = __log_buf; 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); @@ -170,11 +136,11 @@ static int __init log_buf_len_setup(char *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; } @@ -194,15 +160,42 @@ static int __init log_buf_len_setup(char *str) 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; } __setup("log_buf_len=", log_buf_len_setup); +#ifdef CONFIG_BOOT_DELAY + +extern unsigned int boot_delay; /* msecs to delay after each printk during bootup */ +extern long preset_lpj; +extern unsigned long long printk_delay_msec; + +static void boot_delay_msec(int millisecs) +{ + unsigned long long k = printk_delay_msec * millisecs; + unsigned long timeout; + + timeout = jiffies + msecs_to_jiffies(millisecs); + while (k) { + k--; + cpu_relax(); + /* + * use (volatile) jiffies to prevent + * compiler reduction; loop termination via jiffies + * is secondary and may or may not happen. + */ + if (time_after(jiffies, timeout)) + break; + touch_nmi_watchdog(); + } +} + +#endif + /* * Commands to do_syslog: * @@ -218,7 +211,7 @@ __setup("log_buf_len=", log_buf_len_setup); * 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; @@ -250,7 +243,8 @@ int do_syslog(int type, char __user * buf, int len) case 1: /* Open log */ break; case 2: /* Read from log */ - 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; @@ -270,7 +264,7 @@ int do_syslog(int type, char __user * buf, int len) error = i; break; case 4: /* Read/clear last kernel messages */ - do_clear = 1; + do_clear = 1; /* FALL THRU */ case 3: /* Read last kernel messages */ count = len; @@ -284,11 +278,11 @@ int do_syslog(int type, char __user * buf, int len) 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. */ - 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; @@ -302,10 +296,10 @@ int do_syslog(int type, char __user * buf, int len) 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;inext) { - if ((con->flags & CON_ENABLED) && con->write) - con->write(con, buf, len); - } -} - /* * Call the console drivers on a range of log_buf */ @@ -374,7 +354,9 @@ static void __call_console_drivers(unsigned long start, unsigned long end) 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); } } @@ -408,27 +390,24 @@ static void call_console_drivers(unsigned long start, unsigned long end) 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) { /* @@ -471,7 +450,7 @@ static void zap_locks(void) 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; @@ -487,6 +466,7 @@ static int printk_time = 1; #else static int printk_time = 0; #endif +module_param(printk_time, int, S_IRUGO | S_IWUSR); static int __init printk_time_setup(char *str) { @@ -498,9 +478,29 @@ static int __init printk_time_setup(char *str) __setup("time", printk_time_setup); -/* +__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 @@ -510,6 +510,9 @@ __setup("time", printk_time_setup); * 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, ...) @@ -521,10 +524,16 @@ asmlinkage int printk(const char *fmt, ...) r = vprintk(fmt, args); va_end(args); +#ifdef CONFIG_BOOT_DELAY + if (boot_delay && system_state == SYSTEM_BOOTING) + boot_delay_msec(boot_delay); +#endif + return r; } -static volatile int printk_cpu = -1; +/* cpu currently holding logbuf_lock */ +static volatile unsigned int printk_cpu = UINT_MAX; asmlinkage int vprintk(const char *fmt, va_list args) { @@ -534,22 +543,21 @@ asmlinkage int vprintk(const char *fmt, va_list args) static char printk_buf[1024]; static int log_level_unknown = 1; - if (unlikely(oops_in_progress && printk_cpu == smp_processor_id())) + 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); + 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); - if (unlikely(crashdump_mode())) { - crashdump_call_console_drivers(printk_buf, printed_len); - spin_unlock_irqrestore(&logbuf_lock, flags); - goto out; - } - /* * Copy the output into log_buf. If the caller didn't provide * appropriate log level tags, we insert them here @@ -572,12 +580,12 @@ asmlinkage int vprintk(const char *fmt, va_list 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] ", @@ -587,7 +595,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) 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] != '>') { @@ -595,8 +603,8 @@ asmlinkage int vprintk(const char *fmt, va_list args) emit_log_char(default_message_loglevel + '0'); emit_log_char('>'); + printed_len += 3; } - printed_len += 3; } log_level_unknown = 0; if (!*p) @@ -607,35 +615,44 @@ asmlinkage int vprintk(const char *fmt, va_list args) 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(); + 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(); + local_irq_restore(flags); } -out: + + preempt_enable(); return printed_len; } EXPORT_SYMBOL(printk); @@ -643,18 +660,65 @@ EXPORT_SYMBOL(vprintk); #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; +} + +int do_syslog(int type, char __user *buf, int len) { return 0; } -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 @@ -689,6 +753,23 @@ int __init add_preferred_console(char *name, int idx, char *options) 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. * @@ -699,8 +780,11 @@ int __init add_preferred_console(char *name, int idx, char *options) */ 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; @@ -721,7 +805,7 @@ int is_console_locked(void) { return console_locked; } -EXPORT_SYMBOL(is_console_locked); +EXPORT_UNUSED_SYMBOL(is_console_locked); /* June 2006 */ /** * release_console_sem - unlock the console system @@ -743,6 +827,13 @@ void release_console_sem(void) 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; @@ -756,15 +847,22 @@ void release_console_sem(void) 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 && !oops_in_progress && waitqueue_active(&log_wait)) { + /* + * If we printk from within the lock dependency code, + * from within the scheduler code, then do not lock + * up due to self-recursion: + */ + if (!lockdep_internal()) + wake_up_interruptible(&log_wait); + } } 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 @@ -806,7 +904,6 @@ void console_unblank(void) c->unblank(); release_console_sem(); } -EXPORT_SYMBOL(console_unblank); /* * Return the console tty driver structure and its associated index @@ -855,9 +952,9 @@ EXPORT_SYMBOL(console_start); * 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; if (preferred_console < 0) @@ -882,7 +979,8 @@ void register_console(struct console * 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 && @@ -895,8 +993,10 @@ void register_console(struct console * console) 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; } @@ -916,6 +1016,8 @@ void register_console(struct console * console) 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; @@ -933,33 +1035,37 @@ void register_console(struct console * 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; - + else if (console->flags & CON_CONSDEV) + console_drivers->flags |= CON_CONSDEV; release_console_sem(); return res; @@ -968,6 +1074,8 @@ EXPORT_SYMBOL(unregister_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 @@ -990,7 +1098,7 @@ void tty_write_message(struct tty_struct *tty, char *msg) 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; @@ -1003,6 +1111,7 @@ int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst) toks = ratelimit_burst * ratelimit_jiffies; if (toks >= ratelimit_jiffies) { int lost = missed; + missed = 0; toks -= ratelimit_jiffies; spin_unlock_irqrestore(&ratelimit_lock, flags); @@ -1017,7 +1126,7 @@ int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst) 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;