X-Git-Url: https://nv-tegra.nvidia.com/r/gitweb?p=linux-2.6.git;a=blobdiff_plain;f=kernel%2Fprintk.c;h=75077ad0b5378afd3fa89aa9f0199c296a8c0cd7;hp=c770e1a4e882289f66ae0e54451ba186f09c03d2;hb=aae8aab40367036931608fdaf9e2dc568b516f19;hpb=99eea6a105106a94758724ccce996607f60bc0f2 diff --git a/kernel/printk.c b/kernel/printk.c index c770e1a4e88..75077ad0b53 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -13,16 +13,17 @@ * Fixed SMP synchronization, 08/08/99, Manfred Spraul * manfred@colorfullife.com * Rewrote bits to get rid of console_lock - * 01Mar01 Andrew Morton + * 01Mar01 Andrew Morton */ #include #include #include #include -#include #include #include +#include +#include #include #include #include /* For in_interrupt() */ @@ -31,10 +32,26 @@ #include #include #include -#include +#include +#include +#include +#include #include +/* + * for_each_console() allows you to iterate on each console + */ +#define for_each_console(con) \ + for (con = console_drivers; con != NULL; con = con->next) + +/* + * Architectures can override it: + */ +void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) +{ +} + #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) /* printk's without a loglevel use this.. */ @@ -54,7 +71,7 @@ int console_printk[4] = { }; /* - * Low lever drivers may need that to know if they can schedule in + * Low level 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; @@ -66,8 +83,9 @@ EXPORT_SYMBOL(oops_in_progress); * driver system. */ static DECLARE_MUTEX(console_sem); -static DECLARE_MUTEX(secondary_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 @@ -85,16 +103,16 @@ static int console_locked, console_suspended; */ static DEFINE_SPINLOCK(logbuf_lock); -#define LOG_BUF_MASK (log_buf_len-1) +#define LOG_BUF_MASK (log_buf_len-1) #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) /* * The indices into log_buf are not constrained to log_buf_len - they * must be masked before subscripting */ -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 log_start; /* Index into log_buf: next char to be read by syslog() */ +static unsigned con_start; /* Index into log_buf: next char to be sent to consoles */ +static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ /* * Array of consoles built from command line options (console=) @@ -104,6 +122,9 @@ 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 @@ -111,6 +132,8 @@ struct console_cmdline 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; @@ -120,17 +143,36 @@ static int console_may_schedule; 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 */ +static unsigned logged_chars; /* Number of chars produced since last read+clear operation */ +static int saved_console_loglevel = -1; + +#ifdef CONFIG_KEXEC +/* + * This appends the listed symbols to /proc/vmcoreinfo + * + * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to + * obtain access to symbols that are otherwise very difficult to locate. These + * symbols are specifically used so that utilities can access and extract the + * dmesg log from a vmcore file after a crash. + */ +void log_buf_kexec_setup(void) +{ + VMCOREINFO_SYMBOL(log_buf); + VMCOREINFO_SYMBOL(log_end); + VMCOREINFO_SYMBOL(log_buf_len); + VMCOREINFO_SYMBOL(logged_chars); +} +#endif static int __init log_buf_len_setup(char *str) { - unsigned long size = memparse(str, &str); + unsigned 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; + unsigned start, dest_idx, offset; char *new_log_buf; new_log_buf = alloc_bootmem(size); @@ -163,38 +205,76 @@ out: __setup("log_buf_len=", log_buf_len_setup); -/* - * Commands to do_syslog: - * - * 0 -- Close the log. Currently a NOP. - * 1 -- Open the log. Currently a NOP. - * 2 -- Read from the log. - * 3 -- Read all messages remaining in the ring buffer. - * 4 -- Read and clear all messages remaining in the ring buffer - * 5 -- Clear ring buffer. - * 6 -- Disable printk's to console - * 7 -- Enable printk's to console - * 8 -- Set level of messages printed to console - * 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) +#ifdef CONFIG_BOOT_PRINTK_DELAY + +static unsigned int boot_delay; /* msecs delay after each printk during bootup */ +static unsigned long long loops_per_msec; /* based on boot_delay */ + +static int __init boot_delay_setup(char *str) +{ + unsigned long lpj; + + lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ + loops_per_msec = (unsigned long long)lpj / 1000 * HZ; + + get_option(&str, &boot_delay); + if (boot_delay > 10 * 1000) + boot_delay = 0; + + pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " + "HZ: %d, loops_per_msec: %llu\n", + boot_delay, preset_lpj, lpj, HZ, loops_per_msec); + return 1; +} +__setup("boot_delay=", boot_delay_setup); + +static void boot_delay_msec(void) +{ + unsigned long long k; + unsigned long timeout; + + if (boot_delay == 0 || system_state != SYSTEM_BOOTING) + return; + + k = (unsigned long long)loops_per_msec * boot_delay; + + timeout = jiffies + msecs_to_jiffies(boot_delay); + 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(); + } +} +#else +static inline void boot_delay_msec(void) +{ +} +#endif + +int do_syslog(int type, char __user *buf, int len, bool from_file) { - unsigned long i, j, limit, count; + unsigned i, j, limit, count; int do_clear = 0; char c; int error = 0; - error = security_syslog(type); + error = security_syslog(type, from_file); if (error) return error; switch (type) { - case 0: /* Close log */ + case SYSLOG_ACTION_CLOSE: /* Close log */ break; - case 1: /* Open log */ + case SYSLOG_ACTION_OPEN: /* Open log */ break; - case 2: /* Read from log */ + case SYSLOG_ACTION_READ: /* Read from log */ error = -EINVAL; if (!buf || len < 0) goto out; @@ -225,10 +305,12 @@ int do_syslog(int type, char __user *buf, int len) if (!error) error = i; break; - case 4: /* Read/clear last kernel messages */ + /* Read/clear last kernel messages */ + case SYSLOG_ACTION_READ_CLEAR: do_clear = 1; /* FALL THRU */ - case 3: /* Read last kernel messages */ + /* Read last kernel messages */ + case SYSLOG_ACTION_READ_ALL: error = -EINVAL; if (!buf || len < 0) goto out; @@ -281,28 +363,41 @@ int do_syslog(int type, char __user *buf, int len) } } break; - case 5: /* Clear ring buffer */ + /* Clear ring buffer */ + case SYSLOG_ACTION_CLEAR: logged_chars = 0; break; - case 6: /* Disable logging to console */ + /* 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; - case 7: /* Enable logging to console */ - console_loglevel = default_console_loglevel; + /* Enable logging to console */ + case SYSLOG_ACTION_CONSOLE_ON: + if (saved_console_loglevel != -1) { + console_loglevel = saved_console_loglevel; + saved_console_loglevel = -1; + } break; - case 8: /* Set level of messages printed to console */ + /* Set level of messages printed 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; break; - case 9: /* Number of chars in the log buffer */ + /* Number of chars in the log buffer */ + case SYSLOG_ACTION_SIZE_UNREAD: error = log_end - log_start; break; - case 10: /* Size of the log buffer */ + /* Size of the log buffer */ + case SYSLOG_ACTION_SIZE_BUFFER: error = log_buf_len; break; default: @@ -313,19 +408,19 @@ out: return error; } -asmlinkage long sys_syslog(int type, char __user *buf, int len) +SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) { - return do_syslog(type, buf, len); + return do_syslog(type, buf, len, SYSLOG_FROM_CALL); } /* * Call the console drivers on a range of log_buf */ -static void __call_console_drivers(unsigned long start, unsigned long end) +static void __call_console_drivers(unsigned start, unsigned end) { struct console *con; - for (con = console_drivers; con; con = con->next) { + for_each_console(con) { if ((con->flags & CON_ENABLED) && con->write && (cpu_online(smp_processor_id()) || (con->flags & CON_ANYTIME))) @@ -340,16 +435,16 @@ static int __init ignore_loglevel_setup(char *str) ignore_loglevel = 1; printk(KERN_INFO "debug: ignoring loglevel setting.\n"); - return 1; + return 0; } -__setup("ignore_loglevel", ignore_loglevel_setup); +early_param("ignore_loglevel", ignore_loglevel_setup); /* * Write out chars from start to end - 1 inclusive */ -static void _call_console_drivers(unsigned long start, - unsigned long end, int msg_log_level) +static void _call_console_drivers(unsigned start, + unsigned end, int msg_log_level) { if ((msg_log_level < console_loglevel || ignore_loglevel) && console_drivers && start != end) { @@ -369,12 +464,12 @@ static void _call_console_drivers(unsigned long start, * log_buf[start] to log_buf[end - 1]. * The console_sem must be held. */ -static void call_console_drivers(unsigned long start, unsigned long end) +static void call_console_drivers(unsigned start, unsigned end) { - unsigned long cur_index, start_print; + unsigned cur_index, start_print; static int msg_level = -1; - BUG_ON(((long)(start - end)) > 0); + BUG_ON(((int)(start - end)) > 0); cur_index = start; start_print = start; @@ -450,29 +545,14 @@ 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) -{ - 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(); -} +module_param_named(time, printk_time, 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 (con = console_drivers; con; con = con->next) + for_each_console(con) if (con->flags & CON_ANYTIME) return 1; @@ -483,7 +563,7 @@ static int have_callable_console(void) * printk - print a kernel message * @fmt: format string * - * This is printk. It can be called from any context. We want it to work. + * 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 @@ -497,6 +577,8 @@ static int have_callable_console(void) * * See also: * printf(3) + * + * See the vsnprintf() documentation for format string extensions over C99. */ asmlinkage int printk(const char *fmt, ...) @@ -514,122 +596,199 @@ 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_semaphore 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 acquire_console_semaphore_for_printk(unsigned int cpu) +{ + int retval = 0; + + if (!try_acquire_console_sem()) { + 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; + up(&console_sem); + retval = 0; + } + } + printk_cpu = UINT_MAX; + spin_unlock(&logbuf_lock); + return retval; +} +static const char recursion_bug_msg [] = + KERN_CRIT "BUG: recent printk recursion!\n"; +static int recursion_bug; +static int new_text_line = 1; +static char printk_buf[1024]; + +int printk_delay_msec __read_mostly; + +static inline void printk_delay(void) +{ + if (unlikely(printk_delay_msec)) { + int m = printk_delay_msec; + + while (m--) { + mdelay(1); + touch_nmi_watchdog(); + } + } +} + asmlinkage int vprintk(const char *fmt, va_list args) { + int printed_len = 0; + int current_log_level = default_message_loglevel; unsigned long flags; - int printed_len; + int this_cpu; char *p; - static char printk_buf[1024]; - static int log_level_unknown = 1; + + boot_delay_msec(); + printk_delay(); 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 */ + /* This stops the holder of console_sem just where we want him */ + raw_local_irq_save(flags); + this_cpu = smp_processor_id(); + + /* + * Ouch, printk recursed into itself! + */ + if (unlikely(printk_cpu == this_cpu)) { + /* + * If a crash is occurring during printk() on this CPU, + * then try to get the crash message out but make sure + * we can't deadlock. Otherwise just return to avoid the + * recursion and return - but flag the recursion so that + * it can be printed at the next appropriate moment: + */ + if (!oops_in_progress) { + recursion_bug = 1; + goto out_restore_irqs; + } zap_locks(); + } - /* This stops the holder of console_sem just where we want him */ - local_irq_save(flags); lockdep_off(); spin_lock(&logbuf_lock); - printk_cpu = smp_processor_id(); + printk_cpu = this_cpu; + if (recursion_bug) { + recursion_bug = 0; + strcpy(printk_buf, recursion_bug_msg); + printed_len = strlen(recursion_bug_msg); + } /* Emit the output into the temporary buffer */ - printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args); + printed_len += vscnprintf(printk_buf + printed_len, + sizeof(printk_buf) - printed_len, fmt, args); + + + p = printk_buf; + + /* Do we have a loglevel in the string? */ + if (p[0] == '<') { + unsigned char c = p[1]; + if (c && p[2] == '>') { + switch (c) { + case '0' ... '7': /* loglevel */ + current_log_level = c - '0'; + /* Fallthrough - make sure we're on a new line */ + case 'd': /* KERN_DEFAULT */ + if (!new_text_line) { + emit_log_char('\n'); + new_text_line = 1; + } + /* Fallthrough - skip the loglevel */ + case 'c': /* KERN_CONT */ + p += 3; + break; + } + } + } /* * Copy the output into log_buf. If the caller didn't provide * appropriate log level tags, we insert them here */ - for (p = printk_buf; *p; p++) { - if (log_level_unknown) { - /* log_level_unknown signals the start of a new line */ + for ( ; *p; p++) { + if (new_text_line) { + /* Always output the token */ + emit_log_char('<'); + emit_log_char(current_log_level + '0'); + emit_log_char('>'); + printed_len += 3; + new_text_line = 0; + if (printk_time) { - int loglev_char; + /* Follow the token with the time */ 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(); + t = cpu_clock(printk_cpu); nanosec_rem = do_div(t, 1000000000); - tlen = sprintf(tbuf, - "<%c>[%5lu.%06lu] ", - loglev_char, - (unsigned long)t, - nanosec_rem/1000); + tlen = sprintf(tbuf, "[%5lu.%06lu] ", + (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; + new_text_line = 1; } - if (!down_trylock(&console_sem)) { - /* - * We own the drivers. We can drop the spinlock and - * let release_console_sem() print the text, maybe ... - */ - console_locked = 1; - printk_cpu = UINT_MAX; - spin_unlock(&logbuf_lock); + /* + * Try to acquire and then immediately release the + * console semaphore. The release will do all the + * actual magic (print out buffers, wake up klogd, + * etc). + * + * The acquire_console_semaphore_for_printk() function + * will release 'logbuf_lock' regardless of whether it + * actually gets the semaphore or not. + */ + if (acquire_console_semaphore_for_printk(this_cpu)) + release_console_sem(); - /* - * 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. - */ - 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. - */ - printk_cpu = UINT_MAX; - spin_unlock(&logbuf_lock); - lockdep_on(); - local_irq_restore(flags); - } + lockdep_on(); +out_restore_irqs: + raw_local_irq_restore(flags); preempt_enable(); return printed_len; @@ -639,51 +798,92 @@ EXPORT_SYMBOL(vprintk); #else -asmlinkage long sys_syslog(int type, char __user *buf, int len) +static void call_console_drivers(unsigned start, unsigned end) { - return -ENOSYS; } -static void call_console_drivers(unsigned long start, unsigned long 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 name[sizeof(console_cmdline[0].name)]; - char *s, *options; + 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(name, "ttyS"); - strncpy(name + 4, str, sizeof(name) - 5); + strcpy(buf, "ttyS"); + strncpy(buf + 4, str, sizeof(buf) - 5); } else { - strncpy(name, str, sizeof(name) - 1); + strncpy(buf, str, sizeof(buf) - 1); } - name[sizeof(name) - 1] = 0; + buf[sizeof(buf) - 1] = 0; if ((options = strchr(str, ',')) != NULL) *(options++) = 0; #ifdef __sparc__ if (!strcmp(str, "ttya")) - strcpy(name, "ttyS0"); + strcpy(buf, "ttyS0"); if (!strcmp(str, "ttyb")) - strcpy(name, "ttyS1"); + strcpy(buf, "ttyS1"); #endif - for (s = name; *s; s++) + for (s = buf; *s; s++) if ((*s >= '0' && *s <= '9') || *s == ',') break; idx = simple_strtoul(s, NULL, 10); *s = 0; - add_preferred_console(name, idx, options); + __add_preferred_console(buf, idx, options, brl_options); + console_set_on_cmdline = 1; return 1; } __setup("console=", console_setup); @@ -701,33 +901,40 @@ __setup("console=", console_setup); * 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) +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; - /* - * 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++) + 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; + 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; } - 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; + /* not found */ + return -1; } -#ifndef CONFIG_DISABLE_CONSOLE_SUSPEND +int 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); + /** * suspend_console - suspend the console subsystem * @@ -735,17 +942,22 @@ int __init add_preferred_console(char *name, int idx, char *options) */ void suspend_console(void) { - printk("Suspending console(s)\n"); + if (!console_suspend_enabled) + return; + printk("Suspending console(s) (use no_console_suspend to debug)\n"); acquire_console_sem(); console_suspended = 1; + up(&console_sem); } void resume_console(void) { + if (!console_suspend_enabled) + return; + down(&console_sem); console_suspended = 0; release_console_sem(); } -#endif /* CONFIG_DISABLE_CONSOLE_SUSPEND */ /** * acquire_console_sem - lock the console system for exclusive use. @@ -758,11 +970,9 @@ void resume_console(void) void acquire_console_sem(void) { BUG_ON(in_interrupt()); - if (console_suspended) { - down(&secondary_console_sem); - return; - } down(&console_sem); + if (console_suspended) + return; console_locked = 1; console_may_schedule = 1; } @@ -772,6 +982,10 @@ int try_acquire_console_sem(void) { if (down_trylock(&console_sem)) return -1; + if (console_suspended) { + up(&console_sem); + return -1; + } console_locked = 1; console_may_schedule = 0; return 0; @@ -783,6 +997,27 @@ int is_console_locked(void) return console_locked; } +static DEFINE_PER_CPU(int, printk_pending); + +void printk_tick(void) +{ + if (__get_cpu_var(printk_pending)) { + __get_cpu_var(printk_pending) = 0; + wake_up_interruptible(&log_wait); + } +} + +int printk_needs_cpu(int cpu) +{ + return per_cpu(printk_pending, cpu); +} + +void wake_up_klogd(void) +{ + if (waitqueue_active(&log_wait)) + __raw_get_cpu_var(printk_pending) = 1; +} + /** * release_console_sem - unlock the console system * @@ -800,11 +1035,11 @@ int is_console_locked(void) void release_console_sem(void) { unsigned long flags; - unsigned long _con_start, _log_end; - unsigned long wake_klogd = 0; + unsigned _con_start, _log_end; + unsigned wake_klogd = 0; if (console_suspended) { - up(&secondary_console_sem); + up(&console_sem); return; } @@ -819,14 +1054,16 @@ void release_console_sem(void) _log_end = log_end; con_start = log_end; /* Flush */ 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; 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) + wake_up_klogd(); } EXPORT_SYMBOL(release_console_sem); @@ -846,12 +1083,6 @@ void __sched console_conditional_schedule(void) } EXPORT_SYMBOL(console_conditional_schedule); -void console_print(const char *s) -{ - printk(KERN_EMERG "%s", s); -} -EXPORT_SYMBOL(console_print); - void console_unblank(void) { struct console *c; @@ -868,7 +1099,7 @@ void console_unblank(void) console_locked = 1; console_may_schedule = 0; - for (c = console_drivers; c != NULL; c = c->next) + for_each_console(c) if ((c->flags & CON_ENABLED) && c->unblank) c->unblank(); release_console_sem(); @@ -883,7 +1114,7 @@ struct tty_driver *console_device(int *index) struct tty_driver *driver = NULL; acquire_console_sem(); - for (c = console_drivers; c != NULL; c = c->next) { + for_each_console(c) { if (!c->device) continue; driver = c->device(c, index); @@ -920,27 +1151,65 @@ EXPORT_SYMBOL(console_start); * 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 *console) +void register_console(struct console *newcon) { int i; unsigned long flags; + struct console *bcon = NULL; - if (preferred_console < 0) + /* + * 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 (console->index < 0) - console->index = 0; - if (console->setup == NULL || - console->setup(console, NULL) == 0) { - console->flags |= CON_ENABLED | CON_CONSDEV; - 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; + } } } @@ -950,48 +1219,62 @@ void register_console(struct console *console) */ for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) { - if (strcmp(console_cmdline[i].name, console->name) != 0) + if (strcmp(console_cmdline[i].name, newcon->name) != 0) continue; - if (console->index >= 0 && - console->index != console_cmdline[i].index) + if (newcon->index >= 0 && + newcon->index != console_cmdline[i].index) continue; - if (console->index < 0) - console->index = console_cmdline[i].index; - if (console->setup && - console->setup(console, console_cmdline[i].options) != 0) + 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; - console->flags |= CON_ENABLED; - console->index = console_cmdline[i].index; + newcon->flags |= CON_ENABLED; + newcon->index = console_cmdline[i].index; if (i == selected_console) { - console->flags |= CON_CONSDEV; + newcon->flags |= CON_CONSDEV; preferred_console = selected_console; } break; } - if (!(console->flags & CON_ENABLED)) + if (!(newcon->flags & CON_ENABLED)) return; - if (console_drivers && (console_drivers->flags & CON_BOOT)) { - unregister_console(console_drivers); - console->flags &= ~CON_PRINTBUFFER; - } + /* + * 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. */ acquire_console_sem(); - if ((console->flags & CON_CONSDEV) || console_drivers == NULL) { - console->next = console_drivers; - console_drivers = console; - if (console->next) - console->next->flags &= ~CON_CONSDEV; + if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { + newcon->next = console_drivers; + console_drivers = newcon; + if (newcon->next) + newcon->next->flags &= ~CON_CONSDEV; } else { - console->next = console_drivers->next; - console_drivers->next = console; + newcon->next = console_drivers->next; + console_drivers->next = newcon; } - if (console->flags & CON_PRINTBUFFER) { + if (newcon->flags & CON_PRINTBUFFER) { /* * release_console_sem() will print out the buffered messages * for us. @@ -1001,6 +1284,28 @@ void register_console(struct console *console) spin_unlock_irqrestore(&logbuf_lock, flags); } release_console_sem(); + + /* + * 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)) { + /* 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); @@ -1009,6 +1314,11 @@ 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 + acquire_console_sem(); if (console_drivers == console) { console_drivers=console->next; @@ -1024,16 +1334,11 @@ int unregister_console(struct console *console) } } - /* 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) + if (console_drivers != NULL && console->flags & CON_CONSDEV) console_drivers->flags |= CON_CONSDEV; release_console_sem(); @@ -1041,71 +1346,36 @@ int unregister_console(struct console *console) } 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 - * really needed. - */ -void tty_write_message(struct tty_struct *tty, char *msg) +static int __init disable_boot_consoles(void) { - if (tty && tty->driver->write) - tty->driver->write(tty, msg, strlen(msg)); - return; -} + struct console *con; -/* - * printk rate limiting, lifted from the networking subsystem. - * - * This enforces a rate limit: not more than one kernel message - * every printk_ratelimit_jiffies to make a denial-of-service - * attack impossible. - */ -int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst) -{ - static DEFINE_SPINLOCK(ratelimit_lock); - static unsigned long toks = 10 * 5 * HZ; - static unsigned long last_msg; - static int missed; - unsigned long flags; - unsigned long now = jiffies; - - spin_lock_irqsave(&ratelimit_lock, flags); - toks += now - last_msg; - last_msg = now; - if (toks > (ratelimit_burst * ratelimit_jiffies)) - toks = ratelimit_burst * ratelimit_jiffies; - if (toks >= ratelimit_jiffies) { - int lost = missed; - - missed = 0; - toks -= ratelimit_jiffies; - spin_unlock_irqrestore(&ratelimit_lock, flags); - if (lost) - printk(KERN_WARNING "printk: %d messages suppressed.\n", lost); - return 1; + for_each_console(con) { + if (con->flags & CON_BOOT) { + printk(KERN_INFO "turn off boot console %s%d\n", + con->name, con->index); + unregister_console(con); + } } - missed++; - spin_unlock_irqrestore(&ratelimit_lock, flags); return 0; } -EXPORT_SYMBOL(__printk_ratelimit); +late_initcall(disable_boot_consoles); -/* minimum time in jiffies between messages */ -int printk_ratelimit_jiffies = 5 * HZ; +#if defined CONFIG_PRINTK -/* number of messages we send before ratelimiting */ -int printk_ratelimit_burst = 10; +/* + * printk rate limiting, lifted from the networking subsystem. + * + * This enforces a rate limit: not more than 10 kernel messages + * every 5s to make a denial-of-service attack impossible. + */ +DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); -int printk_ratelimit(void) +int __printk_ratelimit(const char *func) { - return __printk_ratelimit(printk_ratelimit_jiffies, - printk_ratelimit_burst); + return ___ratelimit(&printk_ratelimit_state, func); } -EXPORT_SYMBOL(printk_ratelimit); +EXPORT_SYMBOL(__printk_ratelimit); /** * printk_timed_ratelimit - caller-controlled printk ratelimiting @@ -1119,10 +1389,133 @@ EXPORT_SYMBOL(printk_ratelimit); bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msecs) { - if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) { - *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs); + if (*caller_jiffies == 0 + || !time_in_range(jiffies, *caller_jiffies, + *caller_jiffies + + msecs_to_jiffies(interval_msecs))) { + *caller_jiffies = jiffies; return true; } return false; } EXPORT_SYMBOL(printk_timed_ratelimit); + +static DEFINE_SPINLOCK(dump_list_lock); +static LIST_HEAD(dump_list); + +/** + * kmsg_dump_register - register a kernel log dumper. + * @dumper: pointer to the kmsg_dumper structure + * + * Adds a kernel log dumper to the system. The dump callback in the + * structure will be called when the kernel oopses or panics and must be + * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. + */ +int kmsg_dump_register(struct kmsg_dumper *dumper) +{ + unsigned long flags; + int err = -EBUSY; + + /* The dump callback needs to be set */ + if (!dumper->dump) + return -EINVAL; + + spin_lock_irqsave(&dump_list_lock, flags); + /* Don't allow registering multiple times */ + if (!dumper->registered) { + dumper->registered = 1; + list_add_tail(&dumper->list, &dump_list); + err = 0; + } + spin_unlock_irqrestore(&dump_list_lock, flags); + + return err; +} +EXPORT_SYMBOL_GPL(kmsg_dump_register); + +/** + * kmsg_dump_unregister - unregister a kmsg dumper. + * @dumper: pointer to the kmsg_dumper structure + * + * Removes a dump device from the system. Returns zero on success and + * %-EINVAL otherwise. + */ +int kmsg_dump_unregister(struct kmsg_dumper *dumper) +{ + unsigned long flags; + int err = -EINVAL; + + spin_lock_irqsave(&dump_list_lock, flags); + if (dumper->registered) { + dumper->registered = 0; + list_del(&dumper->list); + err = 0; + } + spin_unlock_irqrestore(&dump_list_lock, flags); + + return err; +} +EXPORT_SYMBOL_GPL(kmsg_dump_unregister); + +static const char const *kmsg_reasons[] = { + [KMSG_DUMP_OOPS] = "oops", + [KMSG_DUMP_PANIC] = "panic", + [KMSG_DUMP_KEXEC] = "kexec", +}; + +static const char *kmsg_to_str(enum kmsg_dump_reason reason) +{ + if (reason >= ARRAY_SIZE(kmsg_reasons) || reason < 0) + return "unknown"; + + return kmsg_reasons[reason]; +} + +/** + * kmsg_dump - dump kernel log to kernel message dumpers. + * @reason: the reason (oops, panic etc) for dumping + * + * Iterate through each of the dump devices and call the oops/panic + * callbacks with the log buffer. + */ +void kmsg_dump(enum kmsg_dump_reason reason) +{ + unsigned long end; + unsigned chars; + struct kmsg_dumper *dumper; + const char *s1, *s2; + unsigned long l1, l2; + unsigned long flags; + + /* Theoretically, the log could move on after we do this, but + there's not a lot we can do about that. The new messages + will overwrite the start of what we dump. */ + spin_lock_irqsave(&logbuf_lock, flags); + end = log_end & LOG_BUF_MASK; + chars = logged_chars; + spin_unlock_irqrestore(&logbuf_lock, flags); + + if (logged_chars > end) { + s1 = log_buf + log_buf_len - logged_chars + end; + l1 = logged_chars - end; + + s2 = log_buf; + l2 = end; + } else { + s1 = ""; + l1 = 0; + + s2 = log_buf + end - logged_chars; + l2 = logged_chars; + } + + if (!spin_trylock_irqsave(&dump_list_lock, flags)) { + printk(KERN_ERR "dump_kmsg: dump list lock is held during %s, skipping dump\n", + kmsg_to_str(reason)); + return; + } + list_for_each_entry(dumper, &dump_list, list) + dumper->dump(dumper, reason, s1, l1, s2, l2); + spin_unlock_irqrestore(&dump_list_lock, flags); +} +#endif