X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fprintk.c;h=e877742d0ed04b8bfb93de34759be6e070df050c;hb=94fccaf5b7180ba1fdceb923886c5e7d2752f9fb;hp=8bffe0433072d3f021dcae864f331829ecf291d7;hpb=e28576f437e494f8636fbc811976f4f918270671;p=linux-2.6.git diff --git a/kernel/printk.c b/kernel/printk.c index 8bffe0433..e877742d0 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 */ @@ -30,6 +30,9 @@ #include #include #include +#include +#include +#include #include @@ -53,7 +56,12 @@ int console_printk[4] = { EXPORT_SYMBOL(console_printk); +/* + * Low lever drivers may need that to know if they can schedule in + * their unblank() callback or not. So let's export it. + */ int oops_in_progress; +EXPORT_SYMBOL(oops_in_progress); /* * console_sem protects the console_drivers list, and also @@ -77,11 +85,7 @@ static int console_locked; * It is also used in interesting ways to provide interlocking in * release_console_sem(). */ -static spinlock_t logbuf_lock = SPIN_LOCK_UNLOCKED; - -static char __log_buf[__LOG_BUF_LEN]; -static char *log_buf = __log_buf; -static int log_buf_len = __LOG_BUF_LEN; +static DEFINE_SPINLOCK(logbuf_lock); #define LOG_BUF_MASK (log_buf_len-1) #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) @@ -93,7 +97,6 @@ static int log_buf_len = __LOG_BUF_LEN; static unsigned long log_start; /* Index into log_buf: next char to be read by syslog() */ static unsigned long con_start; /* Index into log_buf: next char to be sent to consoles */ static unsigned long log_end; /* Index into log_buf: most-recently-written-char + 1 */ -static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */ /* * Array of consoles built from command line options (console=) @@ -108,11 +111,19 @@ struct console_cmdline #define MAX_CMDLINECONSOLES 8 static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; +static int selected_console = -1; static int preferred_console = -1; /* Flag: console code may call schedule() */ static int console_may_schedule; +#ifdef CONFIG_PRINTK + +static char __log_buf[__LOG_BUF_LEN]; +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 */ @@ -139,8 +150,8 @@ static int __init console_setup(char *str) if (!strcmp(str, "ttyb")) strcpy(name, "ttyS1"); #endif - for(s = name; *s; s++) - if (*s >= '0' && *s <= '9') + for (s = name; *s; s++) + if ((*s >= '0' && *s <= '9') || *s == ',') break; idx = simple_strtoul(s, NULL, 10); *s = 0; @@ -151,54 +162,20 @@ static int __init console_setup(char *str) __setup("console=", console_setup); -/** - * add_preferred_console - add a device to the list of preferred consoles. - * - * 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 __init add_preferred_console(char *name, int idx, char *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) { - preferred_console = i; - return 0; - } - if (i == MAX_CMDLINECONSOLES) - return -E2BIG; - preferred_console = i; - c = &console_cmdline[i]; - memcpy(c->name, name, sizeof(c->name)); - c->name[sizeof(c->name) - 1] = 0; - c->options = options; - c->index = idx; - return 0; -} - static int __init log_buf_len_setup(char *str) { unsigned long size = memparse(str, &str); unsigned long flags; + if (size) + 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; } @@ -218,10 +195,9 @@ 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; } @@ -242,36 +218,40 @@ __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; char c; - int error = -EPERM; - - if (!vx_check(0, VX_ADMIN|VX_WATCH)) - return error; + int error; error = security_syslog(type); if (error) return error; - switch (type) { - case 0: /* Close log */ - break; - case 1: /* Open log */ - break; - case 2: /* Read from log */ + if ((type >= 2) && (type <= 4)) { error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; - error = verify_area(VERIFY_WRITE,buf,len); - if (error) + if (!access_ok(VERIFY_WRITE, buf, len)) { + error = -EFAULT; goto out; - error = wait_event_interruptible(log_wait, (log_start - log_end)); + } + } + if (!vx_check(0, VX_ADMIN|VX_WATCH)) + return vx_do_syslog(type, buf, len); + + switch (type) { + case 0: /* Close log */ + break; + case 1: /* Open log */ + break; + case 2: /* Read from log */ + error = wait_event_interruptible(log_wait, + (log_start - log_end)); if (error) goto out; i = 0; @@ -283,6 +263,7 @@ int do_syslog(int type, char __user * buf, int len) error = __put_user(c,buf); buf++; i++; + cond_resched(); spin_lock_irq(&logbuf_lock); } spin_unlock_irq(&logbuf_lock); @@ -290,18 +271,9 @@ 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 */ - error = -EINVAL; - if (!buf || len < 0) - goto out; - error = 0; - if (!len) - goto out; - error = verify_area(VERIFY_WRITE,buf,len); - if (error) - goto out; count = len; if (count > log_buf_len) count = log_buf_len; @@ -313,32 +285,34 @@ 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; c = LOG_BUF(j); spin_unlock_irq(&logbuf_lock); error = __put_user(c,&buf[count-1-i]); + cond_resched(); spin_lock_irq(&logbuf_lock); } spin_unlock_irq(&logbuf_lock); 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;i 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) { /* @@ -484,7 +456,7 @@ 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; @@ -495,9 +467,33 @@ static void zap_locks(void) init_MUTEX(&console_sem); } -/* +#if defined(CONFIG_PRINTK_TIME) +static int printk_time = 1; +#else +static int printk_time = 0; +#endif + +static int __init printk_time_setup(char *str) +{ + if (*str) + return 0; + printk_time = 1; + return 1; +} + +__setup("time", printk_time_setup); + +__attribute__((weak)) unsigned long long printk_clock(void) +{ + return sched_clock(); +} + +/** + * printk - print a kernel message + * @fmt: format string + * * This is printk. It can be called from any context. We want it to work. - * + * * We try to grab the console_sem. If we succeed, it's easy - we log the output and * 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 @@ -507,26 +503,46 @@ static void zap_locks(void) * 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, ...) { va_list args; + int r; + + va_start(args, fmt); + r = vprintk(fmt, args); + va_end(args); + + return r; +} + +/* cpu currently holding logbuf_lock */ +static volatile unsigned int printk_cpu = UINT_MAX; + +asmlinkage int vprintk(const char *fmt, va_list args) +{ unsigned long flags; int printed_len; char *p; static char printk_buf[1024]; static int log_level_unknown = 1; - if (unlikely(oops_in_progress)) + 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); + printk_cpu = smp_processor_id(); /* Emit the output into the temporary buffer */ - va_start(args, fmt); printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args); - va_end(args); /* * Copy the output into log_buf. If the caller didn't provide @@ -534,26 +550,65 @@ asmlinkage int printk(const char *fmt, ...) */ for (p = printk_buf; *p; p++) { if (log_level_unknown) { - if (p[0] != '<' || p[1] < '0' || p[1] > '7' || p[2] != '>') { - emit_log_char('<'); - emit_log_char(default_message_loglevel + '0'); - emit_log_char('>'); + /* log_level_unknown signals the start of a new line */ + if (printk_time) { + int loglev_char; + char tbuf[50], *tp; + unsigned tlen; + unsigned long long t; + unsigned long nanosec_rem; + + /* + * force the log level token to be + * before the time output. + */ + if (p[0] == '<' && p[1] >='0' && + p[1] <= '7' && p[2] == '>') { + loglev_char = p[1]; + p += 3; + printed_len -= 3; + } else { + loglev_char = default_message_loglevel + + '0'; + } + t = printk_clock(); + nanosec_rem = do_div(t, 1000000000); + tlen = sprintf(tbuf, + "<%c>[%5lu.%06lu] ", + loglev_char, + (unsigned long)t, + nanosec_rem/1000); + + for (tp = tbuf; tp < tbuf + tlen; tp++) + emit_log_char(*tp); + printed_len += tlen; + } else { + if (p[0] != '<' || p[1] < '0' || + p[1] > '7' || p[2] != '>') { + emit_log_char('<'); + emit_log_char(default_message_loglevel + + '0'); + emit_log_char('>'); + printed_len += 3; + } } log_level_unknown = 0; + if (!*p) + break; } emit_log_char(*p); if (*p == '\n') log_level_unknown = 1; } - if (!cpu_online(smp_processor_id()) && - system_state != SYSTEM_RUNNING) { + if (!cpu_online(smp_processor_id())) { /* * 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.. */ + printk_cpu = UINT_MAX; spin_unlock_irqrestore(&logbuf_lock, flags); goto out; } @@ -563,6 +618,7 @@ asmlinkage int printk(const char *fmt, ...) * We own the drivers. We can drop the spinlock and let * release_console_sem() print the text */ + printk_cpu = UINT_MAX; spin_unlock_irqrestore(&logbuf_lock, flags); console_may_schedule = 0; release_console_sem(); @@ -572,12 +628,72 @@ asmlinkage int printk(const char *fmt, ...) * allows the semaphore holder to proceed and to call the * console drivers with the output which we just produced. */ + printk_cpu = UINT_MAX; spin_unlock_irqrestore(&logbuf_lock, flags); } out: + preempt_enable(); return printed_len; } EXPORT_SYMBOL(printk); +EXPORT_SYMBOL(vprintk); + +#else + +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; +} + +static void call_console_drivers(unsigned long start, unsigned long end) +{ +} + +#endif + +/** + * 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 __init add_preferred_console(char *name, int idx, char *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) { + selected_console = i; + return 0; + } + if (i == MAX_CMDLINECONSOLES) + return -E2BIG; + selected_console = i; + c = &console_cmdline[i]; + memcpy(c->name, name, sizeof(c->name)); + c->name[sizeof(c->name) - 1] = 0; + c->options = options; + c->index = idx; + return 0; +} /** * acquire_console_sem - lock the console system for exclusive use. @@ -597,6 +713,16 @@ void acquire_console_sem(void) } EXPORT_SYMBOL(acquire_console_sem); +int try_acquire_console_sem(void) +{ + if (down_trylock(&console_sem)) + return -1; + console_locked = 1; + console_may_schedule = 0; + return 0; +} +EXPORT_SYMBOL(try_acquire_console_sem); + int is_console_locked(void) { return console_locked; @@ -631,8 +757,9 @@ void release_console_sem(void) _con_start = con_start; _log_end = log_end; con_start = log_end; /* Flush */ - spin_unlock_irqrestore(&logbuf_lock, flags); + spin_unlock(&logbuf_lock); call_console_drivers(_con_start, _log_end); + local_irq_restore(flags); } console_locked = 0; console_may_schedule = 0; @@ -643,7 +770,8 @@ void release_console_sem(void) } 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 @@ -651,12 +779,10 @@ EXPORT_SYMBOL(release_console_sem); * * Must be called within acquire_console_sem(). */ -void console_conditional_schedule(void) +void __sched console_conditional_schedule(void) { - if (console_may_schedule && need_resched()) { - set_current_state(TASK_RUNNING); - schedule(); - } + if (console_may_schedule) + cond_resched(); } EXPORT_SYMBOL(console_conditional_schedule); @@ -671,12 +797,15 @@ void console_unblank(void) struct console *c; /* - * Try to get the console semaphore. If someone else owns it - * we have to return without unblanking because console_unblank - * may be called in interrupt context. + * console_unblank can no longer be called in interrupt context unless + * oops_in_progress is set to 1.. */ - if (down_trylock(&console_sem) != 0) - return; + if (oops_in_progress) { + if (down_trylock(&console_sem) != 0) + return; + } else + acquire_console_sem(); + console_locked = 1; console_may_schedule = 0; for (c = console_drivers; c != NULL; c = c->next) @@ -684,7 +813,47 @@ void console_unblank(void) c->unblank(); release_console_sem(); } -EXPORT_SYMBOL(console_unblank); + +/* + * 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; + + acquire_console_sem(); + for (c = console_drivers; c != NULL; c = c->next) { + if (!c->device) + continue; + driver = c->device(c, index); + if (driver) + break; + } + release_console_sem(); + 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) +{ + acquire_console_sem(); + console->flags &= ~CON_ENABLED; + release_console_sem(); +} +EXPORT_SYMBOL(console_stop); + +void console_start(struct console *console) +{ + acquire_console_sem(); + console->flags |= CON_ENABLED; + release_console_sem(); +} +EXPORT_SYMBOL(console_start); /* * The console driver calls this routine during kernel initialization @@ -692,11 +861,14 @@ EXPORT_SYMBOL(console_unblank); * 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) + preferred_console = selected_console; + /* * See if we want to use this console driver. If we * didn't select a console we take the first one @@ -716,7 +888,8 @@ 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 && @@ -729,14 +902,21 @@ 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; } if (!(console->flags & CON_ENABLED)) return; + if (console_drivers && (console_drivers->flags & CON_BOOT)) { + unregister_console(console_drivers); + console->flags &= ~CON_PRINTBUFFER; + } + /* * Put this console in the list - keep the * preferred driver at the head of the list. @@ -745,6 +925,8 @@ 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; @@ -762,41 +944,47 @@ 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 = -1; - + preferred_console = selected_console; + else if (console->flags & CON_CONSDEV) + console_drivers->flags |= CON_CONSDEV; release_console_sem(); return res; } 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 @@ -805,7 +993,7 @@ EXPORT_SYMBOL(unregister_console); void tty_write_message(struct tty_struct *tty, char *msg) { if (tty && tty->driver->write) - tty->driver->write(tty, 0, msg, strlen(msg)); + tty->driver->write(tty, msg, strlen(msg)); return; } @@ -818,8 +1006,8 @@ void tty_write_message(struct tty_struct *tty, char *msg) */ int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst) { - static spinlock_t ratelimit_lock = SPIN_LOCK_UNLOCKED; - static unsigned long toks = 10*5*HZ; + static DEFINE_SPINLOCK(ratelimit_lock); + static unsigned long toks = 10 * 5 * HZ; static unsigned long last_msg; static int missed; unsigned long flags; @@ -832,6 +1020,7 @@ 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); @@ -846,7 +1035,7 @@ 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;