/* * linux/kernel/printk.c * * Copyright (C) 1991, 1992 Linus Torvalds * * Modified to make sys_syslog() more flexible: added commands to * return the last 4k of kernel messages, regardless of whether * they've been read or not. Added option to suppress kernel printk's * to the console. Added hook for sending the console messages * 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 * manfred@colorfullife.com * Rewrote bits to get rid of console_lock * 01Mar01 Andrew Morton */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) { } #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL #define MINIMUM_CONSOLE_LOGLEVEL 1 #define DEFAULT_CONSOLE_LOGLEVEL 7 DECLARE_WAIT_QUEUE_HEAD(log_wait); int console_printk[4] = { DEFAULT_CONSOLE_LOGLEVEL, DEFAULT_MESSAGE_LOGLEVEL, MINIMUM_CONSOLE_LOGLEVEL, DEFAULT_CONSOLE_LOGLEVEL, }; int oops_in_progress; EXPORT_SYMBOL(oops_in_progress); static DEFINE_SEMAPHORE(console_sem); struct console *console_drivers; EXPORT_SYMBOL_GPL(console_drivers); static int console_locked, console_suspended; static DEFINE_RAW_SPINLOCK(logbuf_lock); #define LOG_BUF_MASK (log_buf_len-1) #define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK]) static unsigned log_start; static unsigned con_start; static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ static struct console *exclusive_console; struct console_cmdline { char name[8]; int index; char *options; #ifdef CONFIG_A11Y_BRAILLE_CONSOLE char *brl_options; #endif }; #define MAX_CMDLINECONSOLES 8 static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; static int selected_console = -1; static int preferred_console = -1; int console_set_on_cmdline; EXPORT_SYMBOL(console_set_on_cmdline); 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 logged_chars; static int saved_console_loglevel = -1; #ifdef CONFIG_KEXEC 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 unsigned long __initdata new_log_buf_len; static int __init log_buf_len_setup(char *str) { unsigned size = memparse(str, &str); if (size) size = roundup_pow_of_two(size); if (size > log_buf_len) new_log_buf_len = size; return 0; } early_param("log_buf_len", log_buf_len_setup); void __init setup_log_buf(int early) { unsigned long flags; unsigned start, dest_idx, offset; char *new_log_buf; int free; if (!new_log_buf_len) return; if (early) { unsigned long mem; mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); if (!mem) return; new_log_buf = __va(mem); } else { new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); } if (unlikely(!new_log_buf)) { pr_err("log_buf_len: %ld bytes not available\n", new_log_buf_len); return; } raw_spin_lock_irqsave(&logbuf_lock, flags); log_buf_len = new_log_buf_len; log_buf = new_log_buf; new_log_buf_len = 0; free = __LOG_BUF_LEN - log_end; offset = start = min(con_start, log_start); dest_idx = 0; while (start != log_end) { unsigned log_idx_mask = start & (__LOG_BUF_LEN - 1); log_buf[dest_idx] = __log_buf[log_idx_mask]; start++; dest_idx++; } log_start -= offset; con_start -= offset; log_end -= offset; raw_spin_unlock_irqrestore(&logbuf_lock, flags); pr_info("log_buf_len: %d\n", log_buf_len); pr_info("early log buf free: %d(%d%%)\n", free, (free * 100) / __LOG_BUF_LEN); } #ifdef CONFIG_BOOT_PRINTK_DELAY static int boot_delay; static unsigned long long loops_per_msec; static int __init boot_delay_setup(char *str) { unsigned long lpj; lpj = preset_lpj ? preset_lpj : 1000000; 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(); if (time_after(jiffies, timeout)) break; touch_nmi_watchdog(); } } #else static inline void boot_delay_msec(void) { } #endif static int log_buf_get_len(void) { return logged_chars; } void log_buf_clear(void) { logged_chars = 0; } int log_buf_copy(char *dest, int idx, int len) { int ret, max; bool took_lock = false; if (!oops_in_progress) { raw_spin_lock_irq(&logbuf_lock); took_lock = true; } max = log_buf_get_len(); if (idx < 0 || idx >= max) { ret = -1; } else { if (len > max - idx) len = max - idx; ret = len; idx += (log_end - max); while (len-- > 0) dest[len] = LOG_BUF(idx + len); } if (took_lock) raw_spin_unlock_irq(&logbuf_lock); return ret; } #ifdef CONFIG_SECURITY_DMESG_RESTRICT int dmesg_restrict = 1; #else int dmesg_restrict; #endif static int syslog_action_restricted(int type) { if (dmesg_restrict) return 1; return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; } static int check_syslog_permissions(int type, bool from_file) { if (from_file && type != SYSLOG_ACTION_OPEN) return 0; if (syslog_action_restricted(type)) { if (capable(CAP_SYSLOG)) return 0; if (capable(CAP_SYS_ADMIN)) { printk_once(KERN_WARNING "%s (%d): " "Attempt to access syslog with CAP_SYS_ADMIN " "but no CAP_SYSLOG (deprecated).\n", current->comm, task_pid_nr(current)); return 0; } return -EPERM; } return 0; } int do_syslog(int type, char __user *buf, int len, bool from_file) { unsigned i, j, limit, count; int do_clear = 0; char c; int error; error = check_syslog_permissions(type, from_file); if (error) goto out; error = security_syslog(type); if (error) return error; switch (type) { case SYSLOG_ACTION_CLOSE: break; case SYSLOG_ACTION_OPEN: break; case SYSLOG_ACTION_READ: error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } error = wait_event_interruptible(log_wait, (log_start - log_end)); if (error) goto out; i = 0; raw_spin_lock_irq(&logbuf_lock); while (!error && (log_start != log_end) && i < len) { c = LOG_BUF(log_start); log_start++; raw_spin_unlock_irq(&logbuf_lock); error = __put_user(c,buf); buf++; i++; cond_resched(); raw_spin_lock_irq(&logbuf_lock); } raw_spin_unlock_irq(&logbuf_lock); if (!error) error = i; break; case SYSLOG_ACTION_READ_CLEAR: do_clear = 1; case SYSLOG_ACTION_READ_ALL: error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } count = len; if (count > log_buf_len) count = log_buf_len; raw_spin_lock_irq(&logbuf_lock); if (count > logged_chars) count = logged_chars; if (do_clear) logged_chars = 0; limit = log_end; for (i = 0; i < count && !error; i++) { j = limit-1-i; if (j + log_buf_len < log_end) break; c = LOG_BUF(j); raw_spin_unlock_irq(&logbuf_lock); error = __put_user(c,&buf[count-1-i]); cond_resched(); raw_spin_lock_irq(&logbuf_lock); } raw_spin_unlock_irq(&logbuf_lock); if (error) break; error = i; if (i != count) { int offset = count-error; for (i = 0; i < error; i++) { if (__get_user(c,&buf[i+offset]) || __put_user(c,&buf[i])) { error = -EFAULT; break; } cond_resched(); } } break; case SYSLOG_ACTION_CLEAR: logged_chars = 0; break; case SYSLOG_ACTION_CONSOLE_OFF: if (saved_console_loglevel == -1) saved_console_loglevel = console_loglevel; console_loglevel = minimum_console_loglevel; break; case SYSLOG_ACTION_CONSOLE_ON: if (saved_console_loglevel != -1) { console_loglevel = saved_console_loglevel; saved_console_loglevel = -1; } break; 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; saved_console_loglevel = -1; error = 0; break; case SYSLOG_ACTION_SIZE_UNREAD: error = log_end - log_start; break; case SYSLOG_ACTION_SIZE_BUFFER: error = log_buf_len; break; default: error = -EINVAL; break; } out: return error; } SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) { return do_syslog(type, buf, len, SYSLOG_FROM_CALL); } #ifdef CONFIG_KGDB_KDB void kdb_syslog_data(char *syslog_data[4]) { syslog_data[0] = log_buf; syslog_data[1] = log_buf + log_buf_len; syslog_data[2] = log_buf + log_end - (logged_chars < log_buf_len ? logged_chars : log_buf_len); syslog_data[3] = log_buf + log_end; } #endif static void __call_console_drivers(unsigned start, unsigned end) { struct console *con; for_each_console(con) { if (exclusive_console && con != exclusive_console) continue; if ((con->flags & CON_ENABLED) && con->write && (cpu_online(smp_processor_id()) || (con->flags & CON_ANYTIME))) con->write(con, &LOG_BUF(start), end - start); } } static bool __read_mostly ignore_loglevel; static int __init ignore_loglevel_setup(char *str) { ignore_loglevel = 1; printk(KERN_INFO "debug: ignoring loglevel setting.\n"); return 0; } early_param("ignore_loglevel", ignore_loglevel_setup); module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" "print all kernel messages to the console."); static void _call_console_drivers(unsigned start, unsigned end, int msg_log_level) { trace_console(&LOG_BUF(0), start, end, log_buf_len); if ((msg_log_level < console_loglevel || ignore_loglevel) && console_drivers && start != end) { if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) { __call_console_drivers(start & LOG_BUF_MASK, log_buf_len); __call_console_drivers(0, end & LOG_BUF_MASK); } else { __call_console_drivers(start, end); } } } static size_t log_prefix(const char *p, unsigned int *level, char *special) { unsigned int lev = 0; char sp = '\0'; size_t len; if (p[0] != '<' || !p[1]) return 0; if (p[2] == '>') { switch (p[1]) { case '0' ... '7': lev = p[1] - '0'; break; case 'c': case 'd': sp = p[1]; break; default: return 0; } len = 3; } else { char *endp = NULL; lev = (simple_strtoul(&p[1], &endp, 10) & 7); if (endp == NULL || endp[0] != '>') return 0; len = (endp + 1) - p; } if (sp && !special) return 0; if (special) { *special = sp; if (sp) return len; } if (level) *level = lev; return len; } static void call_console_drivers(unsigned start, unsigned end) { unsigned cur_index, start_print; static int msg_level = -1; BUG_ON(((int)(start - end)) > 0); cur_index = start; start_print = start; while (cur_index != end) { if (msg_level < 0 && ((end - cur_index) > 2)) { cur_index += log_prefix(&LOG_BUF(cur_index), &msg_level, NULL); start_print = cur_index; } while (cur_index != end) { char c = LOG_BUF(cur_index); cur_index++; if (c == '\n') { if (msg_level < 0) { msg_level = default_message_loglevel; } _call_console_drivers(start_print, cur_index, msg_level); msg_level = -1; start_print = cur_index; break; } } } _call_console_drivers(start_print, end, msg_level); } static void emit_log_char(char c) { LOG_BUF(log_end) = c; log_end++; if (log_end - log_start > log_buf_len) log_start = log_end - log_buf_len; if (log_end - con_start > log_buf_len) con_start = log_end - log_buf_len; if (logged_chars < log_buf_len) logged_chars++; } static void zap_locks(void) { static unsigned long oops_timestamp; if (time_after_eq(jiffies, oops_timestamp) && !time_after(jiffies, oops_timestamp + 30 * HZ)) return; oops_timestamp = jiffies; debug_locks_off(); raw_spin_lock_init(&logbuf_lock); sema_init(&console_sem, 1); } #if defined(CONFIG_PRINTK_TIME) static bool printk_time = 1; #else static bool printk_time = 0; #endif module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); #if defined(CONFIG_PRINTK_CPU_ID) static int printk_cpu_id = 1; #else static int printk_cpu_id = 0; #endif module_param_named(cpu, printk_cpu_id, int, S_IRUGO | S_IWUSR); #if defined(CONFIG_PRINTK_PID) static int printk_pid = 1; #else static int printk_pid; #endif module_param_named(pid, printk_pid, int, S_IRUGO | S_IWUSR); static bool always_kmsg_dump; module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); static int have_callable_console(void) { struct console *con; for_each_console(con) if (con->flags & CON_ANYTIME) return 1; return 0; } asmlinkage int printk(const char *fmt, ...) { va_list args; int r; #ifdef CONFIG_MSM_RTB void *caller = __builtin_return_address(0); uncached_logk_pc(LOGK_LOGBUF, caller, (void *)log_end); #endif #ifdef CONFIG_KGDB_KDB if (unlikely(kdb_trap_printk)) { va_start(args, fmt); r = vkdb_printf(fmt, args); va_end(args); return r; } #endif va_start(args, fmt); r = vprintk(fmt, args); va_end(args); return r; } static volatile unsigned int printk_cpu = UINT_MAX; static inline int can_use_console(unsigned int cpu) { return cpu_online(cpu) || have_callable_console(); } static int console_trylock_for_printk(unsigned int cpu) __releases(&logbuf_lock) { int retval = 0, wake = 0; if (console_trylock()) { retval = 1; if (!can_use_console(cpu)) { console_locked = 0; wake = 1; retval = 0; } } printk_cpu = UINT_MAX; raw_spin_unlock(&logbuf_lock); if (wake) up(&console_sem); 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 this_cpu; char *p; size_t plen; char special; boot_delay_msec(); printk_delay(); local_irq_save(flags); this_cpu = smp_processor_id(); if (unlikely(printk_cpu == this_cpu)) { if (!oops_in_progress && !lockdep_recursing(current)) { recursion_bug = 1; goto out_restore_irqs; } zap_locks(); } lockdep_off(); raw_spin_lock(&logbuf_lock); printk_cpu = this_cpu; if (recursion_bug) { recursion_bug = 0; strcpy(printk_buf, recursion_bug_msg); printed_len = strlen(recursion_bug_msg); } printed_len += vscnprintf(printk_buf + printed_len, sizeof(printk_buf) - printed_len, fmt, args); p = printk_buf; plen = log_prefix(p, ¤t_log_level, &special); if (plen) { p += plen; switch (special) { case 'c': plen = 0; break; case 'd': plen = 0; default: if (!new_text_line) { emit_log_char('\n'); new_text_line = 1; } } } for (; *p; p++) { if (new_text_line) { new_text_line = 0; if (plen) { int i; for (i = 0; i < plen; i++) emit_log_char(printk_buf[i]); printed_len += plen; } else { emit_log_char('<'); emit_log_char(current_log_level + '0'); emit_log_char('>'); printed_len += 3; } if (printk_time) { char tbuf[50], *tp; unsigned tlen; unsigned long long t; unsigned long nanosec_rem; t = cpu_clock(printk_cpu); nanosec_rem = do_div(t, 1000000000); 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; } if (printk_cpu_id) { char tbuf[10], *tp; unsigned tlen; tlen = sprintf(tbuf, "c%u ", printk_cpu); for (tp = tbuf; tp < tbuf + tlen; tp++) emit_log_char(*tp); printed_len += tlen; } if (printk_pid) { char tbuf[10], *tp; unsigned tlen; tlen = sprintf(tbuf, "%6u ", current->pid); for (tp = tbuf; tp < tbuf + tlen; tp++) emit_log_char(*tp); printed_len += tlen; } if (!*p) break; } emit_log_char(*p); if (*p == '\n') new_text_line = 1; } if (console_trylock_for_printk(this_cpu)) console_unlock(); lockdep_on(); out_restore_irqs: local_irq_restore(flags); return printed_len; } EXPORT_SYMBOL(printk); EXPORT_SYMBOL(vprintk); #else static void call_console_drivers(unsigned start, unsigned end) { } #endif static int __add_preferred_console(char *name, int idx, char *options, char *brl_options) { struct console_cmdline *c; int i; 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; } static int __init console_setup(char *str) { char buf[sizeof(console_cmdline[0].name) + 4]; 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 if (str[0] >= '0' && str[0] <= '9') { strcpy(buf, "ttyS"); strncpy(buf + 4, str, sizeof(buf) - 5); } else { strncpy(buf, str, sizeof(buf) - 1); } buf[sizeof(buf) - 1] = 0; if ((options = strchr(str, ',')) != NULL) *(options++) = 0; #ifdef __sparc__ if (!strcmp(str, "ttya")) strcpy(buf, "ttyS0"); if (!strcmp(str, "ttyb")) strcpy(buf, "ttyS1"); #endif for (s = buf; *s; s++) if ((*s >= '0' && *s <= '9') || *s == ',') break; idx = simple_strtoul(s, NULL, 10); *s = 0; __add_preferred_console(buf, idx, options, brl_options); console_set_on_cmdline = 1; return 1; } __setup("console=", console_setup); int add_preferred_console(char *name, int idx, char *options) { return __add_preferred_console(name, idx, options, NULL); } int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) { struct console_cmdline *c; int i; for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) if (strcmp(console_cmdline[i].name, name) == 0 && console_cmdline[i].index == idx) { c = &console_cmdline[i]; strlcpy(c->name, name_new, sizeof(c->name)); c->name[sizeof(c->name) - 1] = 0; c->options = options; c->index = idx_new; return i; } return -1; } bool console_suspend_enabled = 1; EXPORT_SYMBOL(console_suspend_enabled); static int __init console_suspend_disable(char *str) { console_suspend_enabled = 0; return 1; } __setup("no_console_suspend", console_suspend_disable); int suspend_console_deferred = 1; module_param_named( suspend_console_deferred, suspend_console_deferred, int, S_IRUGO | S_IWUSR | S_IWGRP ); module_param_named(console_suspend, console_suspend_enabled, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(console_suspend, "suspend console during suspend" " and hibernate operations"); void suspend_console(void) { if (!console_suspend_enabled) return; printk("Suspending console(s) (use no_console_suspend to debug)\n"); console_lock(); console_suspended = 1; up(&console_sem); } void resume_console(void) { if (!console_suspend_enabled) return; down(&console_sem); console_suspended = 0; console_unlock(); } static void __cpuinit console_flush(struct work_struct *work) { console_lock(); console_unlock(); } static __cpuinitdata DECLARE_WORK(console_cpu_notify_work, console_flush); static int __cpuinit console_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { switch (action) { case CPU_DEAD: case CPU_DOWN_FAILED: case CPU_UP_CANCELED: console_lock(); console_unlock(); break; case CPU_ONLINE: case CPU_DYING: if (!console_trylock()) schedule_work(&console_cpu_notify_work); else console_unlock(); } return NOTIFY_OK; } void console_lock(void) { BUG_ON(in_interrupt()); down(&console_sem); if (console_suspended) return; console_locked = 1; console_may_schedule = 1; } EXPORT_SYMBOL(console_lock); int console_trylock(void) { if (down_trylock(&console_sem)) return 0; if (console_suspended) { up(&console_sem); return 0; } console_locked = 1; console_may_schedule = 0; return 1; } EXPORT_SYMBOL(console_trylock); int is_console_locked(void) { return console_locked; } #define PRINTK_BUF_SIZE 512 #define PRINTK_PENDING_WAKEUP 0x01 #define PRINTK_PENDING_SCHED 0x02 static DEFINE_PER_CPU(int, printk_pending); static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); static void wake_up_klogd_work_func(struct irq_work *irq_work) { int pending = __this_cpu_xchg(printk_pending, 0); if (pending & PRINTK_PENDING_SCHED) { char *buf = __get_cpu_var(printk_sched_buf); printk(KERN_WARNING "[sched_delayed] %s", buf); } if (pending & PRINTK_PENDING_WAKEUP) wake_up_interruptible(&log_wait); } static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { .func = wake_up_klogd_work_func, .flags = IRQ_WORK_LAZY, }; void wake_up_klogd(void) { preempt_disable(); if (waitqueue_active(&log_wait)) { this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); } preempt_enable(); } void console_unlock(void) { unsigned long flags; unsigned _con_start, _log_end; unsigned wake_klogd = 0, retry = 0; if (console_suspended) { up(&console_sem); return; } console_may_schedule = 0; again: for ( ; ; ) { raw_spin_lock_irqsave(&logbuf_lock, flags); wake_klogd |= log_start - log_end; if (con_start == log_end) break; _con_start = con_start; _log_end = log_end; con_start = log_end; raw_spin_unlock(&logbuf_lock); stop_critical_timings(); call_console_drivers(_con_start, _log_end); start_critical_timings(); local_irq_restore(flags); } console_locked = 0; if (unlikely(exclusive_console)) exclusive_console = NULL; raw_spin_unlock(&logbuf_lock); up(&console_sem); raw_spin_lock(&logbuf_lock); if (con_start != log_end) retry = 1; else retry = 0; raw_spin_unlock_irqrestore(&logbuf_lock, flags); if (retry && console_trylock()) goto again; if (wake_klogd) wake_up_klogd(); } EXPORT_SYMBOL(console_unlock); void __sched console_conditional_schedule(void) { if (console_may_schedule) cond_resched(); } EXPORT_SYMBOL(console_conditional_schedule); void console_unblank(void) { struct console *c; if (oops_in_progress) { if (down_trylock(&console_sem) != 0) return; } else console_lock(); console_locked = 1; console_may_schedule = 0; for_each_console(c) if ((c->flags & CON_ENABLED) && c->unblank) c->unblank(); console_unlock(); } struct tty_driver *console_device(int *index) { struct console *c; struct tty_driver *driver = NULL; console_lock(); for_each_console(c) { if (!c->device) continue; driver = c->device(c, index); if (driver) break; } console_unlock(); return driver; } void console_stop(struct console *console) { console_lock(); console->flags &= ~CON_ENABLED; console_unlock(); } EXPORT_SYMBOL(console_stop); void console_start(struct console *console) { console_lock(); console->flags |= CON_ENABLED; console_unlock(); } EXPORT_SYMBOL(console_start); static int __read_mostly keep_bootcon; static int __init keep_bootcon_setup(char *str) { keep_bootcon = 1; printk(KERN_INFO "debug: skip boot console de-registration.\n"); return 0; } early_param("keep_bootcon", keep_bootcon_setup); void register_console(struct console *newcon) { int i; unsigned long flags; struct console *bcon = NULL; if (console_drivers && newcon->flags & CON_BOOT) { 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(); if (preferred_console < 0) { if (newcon->index < 0) newcon->index = 0; if (newcon->setup == NULL || newcon->setup(newcon, NULL) == 0) { newcon->flags |= CON_ENABLED; if (newcon->device) { newcon->flags |= CON_CONSDEV; preferred_console = 0; } } } for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) { if (strcmp(console_cmdline[i].name, newcon->name) != 0) continue; if (newcon->index >= 0 && newcon->index != console_cmdline[i].index) continue; if (newcon->index < 0) newcon->index = console_cmdline[i].index; #ifdef CONFIG_A11Y_BRAILLE_CONSOLE if (console_cmdline[i].brl_options) { newcon->flags |= CON_BRL; braille_register_console(newcon, console_cmdline[i].index, console_cmdline[i].options, console_cmdline[i].brl_options); return; } #endif if (newcon->setup && newcon->setup(newcon, console_cmdline[i].options) != 0) break; newcon->flags |= CON_ENABLED; newcon->index = console_cmdline[i].index; if (i == selected_console) { newcon->flags |= CON_CONSDEV; preferred_console = selected_console; } break; } if (!(newcon->flags & CON_ENABLED)) return; if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) newcon->flags &= ~CON_PRINTBUFFER; console_lock(); if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { newcon->next = console_drivers; console_drivers = newcon; if (newcon->next) newcon->next->flags &= ~CON_CONSDEV; } else { newcon->next = console_drivers->next; console_drivers->next = newcon; } if (newcon->flags & CON_PRINTBUFFER) { raw_spin_lock_irqsave(&logbuf_lock, flags); con_start = log_start; raw_spin_unlock_irqrestore(&logbuf_lock, flags); exclusive_console = newcon; } console_unlock(); console_sysfs_notify(); if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && !keep_bootcon) { printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", newcon->name, newcon->index); for_each_console(bcon) if (bcon->flags & CON_BOOT) unregister_console(bcon); } else { printk(KERN_INFO "%sconsole [%s%d] enabled\n", (newcon->flags & CON_BOOT) ? "boot" : "" , newcon->name, newcon->index); } } EXPORT_SYMBOL(register_console); int unregister_console(struct console *console) { struct console *a, *b; int res = 1; #ifdef CONFIG_A11Y_BRAILLE_CONSOLE if (console->flags & CON_BRL) return braille_unregister_console(console); #endif console_lock(); if (console_drivers == console) { console_drivers=console->next; res = 0; } else if (console_drivers) { for (a=console_drivers->next, b=console_drivers ; a; b=a, a=b->next) { if (a == console) { b->next = a->next; res = 0; break; } } } if (console_drivers != NULL && console->flags & CON_CONSDEV) console_drivers->flags |= CON_CONSDEV; console_unlock(); console_sysfs_notify(); return res; } EXPORT_SYMBOL(unregister_console); static int __init printk_late_init(void) { struct console *con; for_each_console(con) { if (!keep_bootcon && con->flags & CON_BOOT) { printk(KERN_INFO "turn off boot console %s%d\n", con->name, con->index); unregister_console(con); } } hotcpu_notifier(console_cpu_notify, 0); return 0; } late_initcall(printk_late_init); #if defined CONFIG_PRINTK int printk_deferred(const char *fmt, ...) { unsigned long flags; va_list args; char *buf; int r; local_irq_save(flags); buf = __get_cpu_var(printk_sched_buf); va_start(args, fmt); r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); va_end(args); __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); local_irq_restore(flags); return r; } DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); int __printk_ratelimit(const char *func) { return ___ratelimit(&printk_ratelimit_state, func); } EXPORT_SYMBOL(__printk_ratelimit); bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int 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); int kmsg_dump_register(struct kmsg_dumper *dumper) { unsigned long flags; int err = -EBUSY; if (!dumper->dump) return -EINVAL; spin_lock_irqsave(&dump_list_lock, flags); if (!dumper->registered) { dumper->registered = 1; list_add_tail_rcu(&dumper->list, &dump_list); err = 0; } spin_unlock_irqrestore(&dump_list_lock, flags); return err; } EXPORT_SYMBOL_GPL(kmsg_dump_register); 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_rcu(&dumper->list); err = 0; } spin_unlock_irqrestore(&dump_list_lock, flags); synchronize_rcu(); return err; } EXPORT_SYMBOL_GPL(kmsg_dump_unregister); 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; if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) return; raw_spin_lock_irqsave(&logbuf_lock, flags); end = log_end & LOG_BUF_MASK; chars = logged_chars; raw_spin_unlock_irqrestore(&logbuf_lock, flags); if (chars > end) { s1 = log_buf + log_buf_len - chars + end; l1 = chars - end; s2 = log_buf; l2 = end; } else { s1 = ""; l1 = 0; s2 = log_buf + end - chars; l2 = chars; } rcu_read_lock(); list_for_each_entry_rcu(dumper, &dump_list, list) dumper->dump(dumper, reason, s1, l1, s2, l2); rcu_read_unlock(); } #endif