diff options
| -rw-r--r-- | kernel/printk.c | 2928 |
1 files changed, 0 insertions, 2928 deletions
diff --git a/kernel/printk.c b/kernel/printk.c deleted file mode 100644 index cd0ee46eb894..000000000000 --- a/kernel/printk.c +++ /dev/null @@ -1,2928 +0,0 @@ -/* - * 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 <linux/kernel.h> -#include <linux/mm.h> -#include <linux/tty.h> -#include <linux/tty_driver.h> -#include <linux/console.h> -#include <linux/init.h> -#include <linux/jiffies.h> -#include <linux/nmi.h> -#include <linux/module.h> -#include <linux/moduleparam.h> -#include <linux/interrupt.h> /* For in_interrupt() */ -#include <linux/delay.h> -#include <linux/smp.h> -#include <linux/security.h> -#include <linux/bootmem.h> -#include <linux/memblock.h> -#include <linux/aio.h> -#include <linux/syscalls.h> -#include <linux/kexec.h> -#include <linux/kdb.h> -#include <linux/ratelimit.h> -#include <linux/kmsg_dump.h> -#include <linux/syslog.h> -#include <linux/cpu.h> -#include <linux/notifier.h> -#include <linux/rculist.h> -#include <linux/poll.h> -#include <linux/irq_work.h> -#include <linux/utsname.h> - -#include <asm/uaccess.h> - -#define CREATE_TRACE_POINTS -#include <trace/events/printk.h> - -/* printk's without a loglevel use this.. */ -#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL - -/* We show everything that is MORE important than this.. */ -#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ -#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ - -int console_printk[4] = { - DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ - DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ - MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ - DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ -}; - -/* - * 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; -EXPORT_SYMBOL(oops_in_progress); - -/* - * console_sem protects the console_drivers list, and also - * provides serialisation for access to the entire console - * driver system. - */ -static DEFINE_SEMAPHORE(console_sem); -struct console *console_drivers; -EXPORT_SYMBOL_GPL(console_drivers); - -#ifdef CONFIG_LOCKDEP -static struct lockdep_map console_lock_dep_map = { - .name = "console_lock" -}; -#endif - -/* - * This is used for debugging the mess that is the VT code by - * keeping track if we have the console semaphore held. It's - * definitely not the perfect debug tool (we don't know if _WE_ - * hold it are racing, but it helps tracking those weird code - * path in the console code where we end up in places I want - * locked without the console sempahore held - */ -static int console_locked, console_suspended; - -/* - * If exclusive_console is non-NULL then only this console is to be printed to. - */ -static struct console *exclusive_console; - -/* - * Array of consoles built from command line options (console=) - */ -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 - -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; - -/* - * The printk log buffer consists of a chain of concatenated variable - * length records. Every record starts with a record header, containing - * the overall length of the record. - * - * The heads to the first and last entry in the buffer, as well as the - * sequence numbers of these both entries are maintained when messages - * are stored.. - * - * If the heads indicate available messages, the length in the header - * tells the start next message. A length == 0 for the next message - * indicates a wrap-around to the beginning of the buffer. - * - * Every record carries the monotonic timestamp in microseconds, as well as - * the standard userspace syslog level and syslog facility. The usual - * kernel messages use LOG_KERN; userspace-injected messages always carry - * a matching syslog facility, by default LOG_USER. The origin of every - * message can be reliably determined that way. - * - * The human readable log message directly follows the message header. The - * length of the message text is stored in the header, the stored message - * is not terminated. - * - * Optionally, a message can carry a dictionary of properties (key/value pairs), - * to provide userspace with a machine-readable message context. - * - * Examples for well-defined, commonly used property names are: - * DEVICE=b12:8 device identifier - * b12:8 block dev_t - * c127:3 char dev_t - * n8 netdev ifindex - * +sound:card0 subsystem:devname - * SUBSYSTEM=pci driver-core subsystem name - * - * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value - * follows directly after a '=' character. Every property is terminated by - * a '\0' character. The last property is not terminated. - * - * Example of a message structure: - * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec - * 0008 34 00 record is 52 bytes long - * 000a 0b 00 text is 11 bytes long - * 000c 1f 00 dictionary is 23 bytes long - * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) - * 0010 69 74 27 73 20 61 20 6c "it's a l" - * 69 6e 65 "ine" - * 001b 44 45 56 49 43 "DEVIC" - * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" - * 52 49 56 45 52 3d 62 75 "RIVER=bu" - * 67 "g" - * 0032 00 00 00 padding to next message header - * - * The 'struct log' buffer header must never be directly exported to - * userspace, it is a kernel-private implementation detail that might - * need to be changed in the future, when the requirements change. - * - * /dev/kmsg exports the structured data in the following line format: - * "level,sequnum,timestamp;<message text>\n" - * - * The optional key/value pairs are attached as continuation lines starting - * with a space character and terminated by a newline. All possible - * non-prinatable characters are escaped in the "\xff" notation. - * - * Users of the export format should ignore possible additional values - * separated by ',', and find the message after the ';' character. - */ - -enum log_flags { - LOG_NOCONS = 1, /* already flushed, do not print to console */ - LOG_NEWLINE = 2, /* text ended with a newline */ - LOG_PREFIX = 4, /* text started with a prefix */ - LOG_CONT = 8, /* text is a fragment of a continuation line */ -}; - -struct log { - u64 ts_nsec; /* timestamp in nanoseconds */ - u16 len; /* length of entire record */ - u16 text_len; /* length of text buffer */ - u16 dict_len; /* length of dictionary buffer */ - u8 facility; /* syslog facility */ - u8 flags:5; /* internal record flags */ - u8 level:3; /* syslog level */ -}; - -/* - * The logbuf_lock protects kmsg buffer, indices, counters. It is also - * used in interesting ways to provide interlocking in console_unlock(); - */ -static DEFINE_RAW_SPINLOCK(logbuf_lock); - -#ifdef CONFIG_PRINTK -DECLARE_WAIT_QUEUE_HEAD(log_wait); -/* the next printk record to read by syslog(READ) or /proc/kmsg */ -static u64 syslog_seq; -static u32 syslog_idx; -static enum log_flags syslog_prev; -static size_t syslog_partial; - -/* index and sequence number of the first record stored in the buffer */ -static u64 log_first_seq; -static u32 log_first_idx; - -/* index and sequence number of the next record to store in the buffer */ -static u64 log_next_seq; -static u32 log_next_idx; - -/* the next printk record to write to the console */ -static u64 console_seq; -static u32 console_idx; -static enum log_flags console_prev; - -/* the next printk record to read after the last 'clear' command */ -static u64 clear_seq; -static u32 clear_idx; - -#define PREFIX_MAX 32 -#define LOG_LINE_MAX 1024 - PREFIX_MAX - -/* record buffer */ -#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) -#define LOG_ALIGN 4 -#else -#define LOG_ALIGN __alignof__(struct log) -#endif -#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) -static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); -static char *log_buf = __log_buf; -static u32 log_buf_len = __LOG_BUF_LEN; - -/* cpu currently holding logbuf_lock */ -static volatile unsigned int logbuf_cpu = UINT_MAX; - -/* human readable text of the record */ -static char *log_text(const struct log *msg) -{ - return (char *)msg + sizeof(struct log); -} - -/* optional key/value pair dictionary attached to the record */ -static char *log_dict(const struct log *msg) -{ - return (char *)msg + sizeof(struct log) + msg->text_len; -} - -/* get record by index; idx must point to valid msg */ -static struct log *log_from_idx(u32 idx) -{ - struct log *msg = (struct log *)(log_buf + idx); - - /* - * A length == 0 record is the end of buffer marker. Wrap around and - * read the message at the start of the buffer. - */ - if (!msg->len) - return (struct log *)log_buf; - return msg; -} - -/* get next record; idx must point to valid msg */ -static u32 log_next(u32 idx) -{ - struct log *msg = (struct log *)(log_buf + idx); - - /* length == 0 indicates the end of the buffer; wrap */ - /* - * A length == 0 record is the end of buffer marker. Wrap around and - * read the message at the start of the buffer as *this* one, and - * return the one after that. - */ - if (!msg->len) { - msg = (struct log *)log_buf; - return msg->len; - } - return idx + msg->len; -} - -/* insert record into the buffer, discard old ones, update heads */ -static void log_store(int facility, int level, - enum log_flags flags, u64 ts_nsec, - const char *dict, u16 dict_len, - const char *text, u16 text_len) -{ - struct log *msg; - u32 size, pad_len; - - /* number of '\0' padding bytes to next message */ - size = sizeof(struct log) + text_len + dict_len; - pad_len = (-size) & (LOG_ALIGN - 1); - size += pad_len; - - while (log_first_seq < log_next_seq) { - u32 free; - - if (log_next_idx > log_first_idx) - free = max(log_buf_len - log_next_idx, log_first_idx); - else - free = log_first_idx - log_next_idx; - - if (free > size + sizeof(struct log)) - break; - - /* drop old messages until we have enough contiuous space */ - log_first_idx = log_next(log_first_idx); - log_first_seq++; - } - - if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { - /* - * This message + an additional empty header does not fit - * at the end of the buffer. Add an empty header with len == 0 - * to signify a wrap around. - */ - memset(log_buf + log_next_idx, 0, sizeof(struct log)); - log_next_idx = 0; - } - - /* fill message */ - msg = (struct log *)(log_buf + log_next_idx); - memcpy(log_text(msg), text, text_len); - msg->text_len = text_len; - memcpy(log_dict(msg), dict, dict_len); - msg->dict_len = dict_len; - msg->facility = facility; - msg->level = level & 7; - msg->flags = flags & 0x1f; - if (ts_nsec > 0) - msg->ts_nsec = ts_nsec; - else - msg->ts_nsec = local_clock(); - memset(log_dict(msg) + dict_len, 0, pad_len); - msg->len = sizeof(struct log) + text_len + dict_len + pad_len; - - /* insert message */ - log_next_idx += msg->len; - log_next_seq++; -} - -#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; - /* - * Unless restricted, we allow "read all" and "get buffer size" - * for everybody. - */ - return type != SYSLOG_ACTION_READ_ALL && - type != SYSLOG_ACTION_SIZE_BUFFER; -} - -static int check_syslog_permissions(int type, bool from_file) -{ - /* - * If this is from /proc/kmsg and we've already opened it, then we've - * already done the capabilities checks at open time. - */ - if (from_file && type != SYSLOG_ACTION_OPEN) - return 0; - - if (syslog_action_restricted(type)) { - if (capable(CAP_SYSLOG)) - return 0; - /* - * For historical reasons, accept CAP_SYS_ADMIN too, with - * a warning. - */ - if (capable(CAP_SYS_ADMIN)) { - pr_warn_once("%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 security_syslog(type); -} - - -/* /dev/kmsg - userspace message inject/listen interface */ -struct devkmsg_user { - u64 seq; - u32 idx; - enum log_flags prev; - struct mutex lock; - char buf[8192]; -}; - -static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, - unsigned long count, loff_t pos) -{ - char *buf, *line; - int i; - int level = default_message_loglevel; - int facility = 1; /* LOG_USER */ - size_t len = iov_length(iv, count); - ssize_t ret = len; - - if (len > LOG_LINE_MAX) - return -EINVAL; - buf = kmalloc(len+1, GFP_KERNEL); - if (buf == NULL) - return -ENOMEM; - - line = buf; - for (i = 0; i < count; i++) { - if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) { - ret = -EFAULT; - goto out; - } - line += iv[i].iov_len; - } - - /* - * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace - * the decimal value represents 32bit, the lower 3 bit are the log - * level, the rest are the log facility. - * - * If no prefix or no userspace facility is specified, we - * enforce LOG_USER, to be able to reliably distinguish - * kernel-generated messages from userspace-injected ones. - */ - line = buf; - if (line[0] == '<') { - char *endp = NULL; - - i = simple_strtoul(line+1, &endp, 10); - if (endp && endp[0] == '>') { - level = i & 7; - if (i >> 3) - facility = i >> 3; - endp++; - len -= endp - line; - line = endp; - } - } - line[len] = '\0'; - - printk_emit(facility, level, NULL, 0, "%s", line); -out: - kfree(buf); - return ret; -} - -static ssize_t devkmsg_read(struct file *file, char __user *buf, - size_t count, loff_t *ppos) -{ - struct devkmsg_user *user = file->private_data; - struct log *msg; - u64 ts_usec; - size_t i; - char cont = '-'; - size_t len; - ssize_t ret; - - if (!user) - return -EBADF; - - ret = mutex_lock_interruptible(&user->lock); - if (ret) - return ret; - raw_spin_lock_irq(&logbuf_lock); - while (user->seq == log_next_seq) { - if (file->f_flags & O_NONBLOCK) { - ret = -EAGAIN; - raw_spin_unlock_irq(&logbuf_lock); - goto out; - } - - raw_spin_unlock_irq(&logbuf_lock); - ret = wait_event_interruptible(log_wait, - user->seq != log_next_seq); - if (ret) - goto out; - raw_spin_lock_irq(&logbuf_lock); - } - - if (user->seq < log_first_seq) { - /* our last seen message is gone, return error and reset */ - user->idx = log_first_idx; - user->seq = log_first_seq; - ret = -EPIPE; - raw_spin_unlock_irq(&logbuf_lock); - goto out; - } - - msg = log_from_idx(user->idx); - ts_usec = msg->ts_nsec; - do_div(ts_usec, 1000); - - /* - * If we couldn't merge continuation line fragments during the print, - * export the stored flags to allow an optional external merge of the - * records. Merging the records isn't always neccessarily correct, like - * when we hit a race during printing. In most cases though, it produces - * better readable output. 'c' in the record flags mark the first - * fragment of a line, '+' the following. - */ - if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT)) - cont = 'c'; - else if ((msg->flags & LOG_CONT) || - ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) - cont = '+'; - - len = sprintf(user->buf, "%u,%llu,%llu,%c;", - (msg->facility << 3) | msg->level, - user->seq, ts_usec, cont); - user->prev = msg->flags; - - /* escape non-printable characters */ - for (i = 0; i < msg->text_len; i++) { - unsigned char c = log_text(msg)[i]; - - if (c < ' ' || c >= 127 || c == '\\') - len += sprintf(user->buf + len, "\\x%02x", c); - else - user->buf[len++] = c; - } - user->buf[len++] = '\n'; - - if (msg->dict_len) { - bool line = true; - - for (i = 0; i < msg->dict_len; i++) { - unsigned char c = log_dict(msg)[i]; - - if (line) { - user->buf[len++] = ' '; - line = false; - } - - if (c == '\0') { - user->buf[len++] = '\n'; - line = true; - continue; - } - - if (c < ' ' || c >= 127 || c == '\\') { - len += sprintf(user->buf + len, "\\x%02x", c); - continue; - } - - user->buf[len++] = c; - } - user->buf[len++] = '\n'; - } - - user->idx = log_next(user->idx); - user->seq++; - raw_spin_unlock_irq(&logbuf_lock); - - if (len > count) { - ret = -EINVAL; - goto out; - } - - if (copy_to_user(buf, user->buf, len)) { - ret = -EFAULT; - goto out; - } - ret = len; -out: - mutex_unlock(&user->lock); - return ret; -} - -static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) -{ - struct devkmsg_user *user = file->private_data; - loff_t ret = 0; - - if (!user) - return -EBADF; - if (offset) - return -ESPIPE; - - raw_spin_lock_irq(&logbuf_lock); - switch (whence) { - case SEEK_SET: - /* the first record */ - user->idx = log_first_idx; - user->seq = log_first_seq; - break; - case SEEK_DATA: - /* - * The first record after the last SYSLOG_ACTION_CLEAR, - * like issued by 'dmesg -c'. Reading /dev/kmsg itself - * changes no global state, and does not clear anything. - */ - user->idx = clear_idx; - user->seq = clear_seq; - break; - case SEEK_END: - /* after the last record */ - user->idx = log_next_idx; - user->seq = log_next_seq; - break; - default: - ret = -EINVAL; - } - raw_spin_unlock_irq(&logbuf_lock); - return ret; -} - -static unsigned int devkmsg_poll(struct file *file, poll_table *wait) -{ - struct devkmsg_user *user = file->private_data; - int ret = 0; - - if (!user) - return POLLERR|POLLNVAL; - - poll_wait(file, &log_wait, wait); - - raw_spin_lock_irq(&logbuf_lock); - if (user->seq < log_next_seq) { - /* return error when data has vanished underneath us */ - if (user->seq < log_first_seq) - ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; - else - ret = POLLIN|POLLRDNORM; - } - raw_spin_unlock_irq(&logbuf_lock); - - return ret; -} - -static int devkmsg_open(struct inode *inode, struct file *file) -{ - struct devkmsg_user *user; - int err; - - /* write-only does not need any file context */ - if ((file->f_flags & O_ACCMODE) == O_WRONLY) - return 0; - - err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, - SYSLOG_FROM_READER); - if (err) - return err; - - user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); - if (!user) - return -ENOMEM; - - mutex_init(&user->lock); - - raw_spin_lock_irq(&logbuf_lock); - user->idx = log_first_idx; - user->seq = log_first_seq; - raw_spin_unlock_irq(&logbuf_lock); - - file->private_data = user; - return 0; -} - -static int devkmsg_release(struct inode *inode, struct file *file) -{ - struct devkmsg_user *user = file->private_data; - - if (!user) - return 0; - - mutex_destroy(&user->lock); - kfree(user); - return 0; -} - -const struct file_operations kmsg_fops = { - .open = devkmsg_open, - .read = devkmsg_read, - .aio_write = devkmsg_writev, - .llseek = devkmsg_llseek, - .poll = devkmsg_poll, - .release = devkmsg_release, -}; - -#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_buf_len); - VMCOREINFO_SYMBOL(log_first_idx); - VMCOREINFO_SYMBOL(log_next_idx); - /* - * Export struct log size and field offsets. User space tools can - * parse it and detect any changes to structure down the line. - */ - VMCOREINFO_STRUCT_SIZE(log); - VMCOREINFO_OFFSET(log, ts_nsec); - VMCOREINFO_OFFSET(log, len); - VMCOREINFO_OFFSET(log, text_len); - VMCOREINFO_OFFSET(log, dict_len); -} -#endif - -/* requested log_buf_len from kernel cmdline */ -static unsigned long __initdata new_log_buf_len; - -/* save requested log_buf_len since it's too early to process it */ -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; - 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_next_idx; - memcpy(log_buf, __log_buf, __LOG_BUF_LEN); - 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); -} - -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."); - -#ifdef CONFIG_BOOT_PRINTK_DELAY - -static 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(int level) -{ - unsigned long long k; - unsigned long timeout; - - if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) - || (level >= console_loglevel && !ignore_loglevel)) { - 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(int level) -{ -} -#endif - -#if defined(CONFIG_PRINTK_TIME) -static bool printk_time = 1; -#else -static bool printk_time; -#endif -module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); - -static size_t print_time(u64 ts, char *buf) -{ - unsigned long rem_nsec; - - if (!printk_time) - return 0; - - rem_nsec = do_div(ts, 1000000000); - - if (!buf) - return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); - - return sprintf(buf, "[%5lu.%06lu] ", - (unsigned long)ts, rem_nsec / 1000); -} - -static size_t print_prefix(const struct log *msg, bool syslog, char *buf) -{ - size_t len = 0; - unsigned int prefix = (msg->facility << 3) | msg->level; - - if (syslog) { - if (buf) { - len += sprintf(buf, "<%u>", prefix); - } else { - len += 3; - if (prefix > 999) - len += 3; - else if (prefix > 99) - len += 2; - else if (prefix > 9) - len++; - } - } - - len += print_time(msg->ts_nsec, buf ? buf + len : NULL); - return len; -} - -static size_t msg_print_text(const struct log *msg, enum log_flags prev, - bool syslog, char *buf, size_t size) -{ - const char *text = log_text(msg); - size_t text_size = msg->text_len; - bool prefix = true; - bool newline = true; - size_t len = 0; - - if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) - prefix = false; - - if (msg->flags & LOG_CONT) { - if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) - prefix = false; - - if (!(msg->flags & LOG_NEWLINE)) - newline = false; - } - - do { - const char *next = memchr(text, '\n', text_size); - size_t text_len; - - if (next) { - text_len = next - text; - next++; - text_size -= next - text; - } else { - text_len = text_size; - } - - if (buf) { - if (print_prefix(msg, syslog, NULL) + - text_len + 1 >= size - len) - break; - - if (prefix) - len += print_prefix(msg, syslog, buf + len); - memcpy(buf + len, text, text_len); - len += text_len; - if (next || newline) - buf[len++] = '\n'; - } else { - /* SYSLOG_ACTION_* buffer size only calculation */ - if (prefix) - len += print_prefix(msg, syslog, NULL); - len += text_len; - if (next || newline) - len++; - } - - prefix = true; - text = next; - } while (text); - - return len; -} - -static int syslog_print(char __user *buf, int size) -{ - char *text; - struct log *msg; - int len = 0; - - text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); - if (!text) - return -ENOMEM; - - while (size > 0) { - size_t n; - size_t skip; - - raw_spin_lock_irq(&logbuf_lock); - if (syslog_seq < log_first_seq) { - /* messages are gone, move to first one */ - syslog_seq = log_first_seq; - syslog_idx = log_first_idx; - syslog_prev = 0; - syslog_partial = 0; - } - if (syslog_seq == log_next_seq) { - raw_spin_unlock_irq(&logbuf_lock); - break; - } - - skip = syslog_partial; - msg = log_from_idx(syslog_idx); - n = msg_print_text(msg, syslog_prev, true, text, - LOG_LINE_MAX + PREFIX_MAX); - if (n - syslog_partial <= size) { - /* message fits into buffer, move forward */ - syslog_idx = log_next(syslog_idx); - syslog_seq++; - syslog_prev = msg->flags; - n -= syslog_partial; - syslog_partial = 0; - } else if (!len){ - /* partial read(), remember position */ - n = size; - syslog_partial += n; - } else - n = 0; - raw_spin_unlock_irq(&logbuf_lock); - - if (!n) - break; - - if (copy_to_user(buf, text + skip, n)) { - if (!len) - len = -EFAULT; - break; - } - - len += n; - size -= n; - buf += n; - } - - kfree(text); - return len; -} - -static int syslog_print_all(char __user *buf, int size, bool clear) -{ - char *text; - int len = 0; - - text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); - if (!text) - return -ENOMEM; - - raw_spin_lock_irq(&logbuf_lock); - if (buf) { - u64 next_seq; - u64 seq; - u32 idx; - enum log_flags prev; - - if (clear_seq < log_first_seq) { - /* messages are gone, move to first available one */ - clear_seq = log_first_seq; - clear_idx = log_first_idx; - } - - /* - * Find first record that fits, including all following records, - * into the user-provided buffer for this dump. - */ - seq = clear_seq; - idx = clear_idx; - prev = 0; - while (seq < log_next_seq) { - struct log *msg = log_from_idx(idx); - - len += msg_print_text(msg, prev, true, NULL, 0); - prev = msg->flags; - idx = log_next(idx); - seq++; - } - - /* move first record forward until length fits into the buffer */ - seq = clear_seq; - idx = clear_idx; - prev = 0; - while (len > size && seq < log_next_seq) { - struct log *msg = log_from_idx(idx); - - len -= msg_print_text(msg, prev, true, NULL, 0); - prev = msg->flags; - idx = log_next(idx); - seq++; - } - - /* last message fitting into this dump */ - next_seq = log_next_seq; - - len = 0; - prev = 0; - while (len >= 0 && seq < next_seq) { - struct log *msg = log_from_idx(idx); - int textlen; - - textlen = msg_print_text(msg, prev, true, text, - LOG_LINE_MAX + PREFIX_MAX); - if (textlen < 0) { - len = textlen; - break; - } - idx = log_next(idx); - seq++; - prev = msg->flags; - - raw_spin_unlock_irq(&logbuf_lock); - if (copy_to_user(buf + len, text, textlen)) - len = -EFAULT; - else - len += textlen; - raw_spin_lock_irq(&logbuf_lock); - - if (seq < log_first_seq) { - /* messages are gone, move to next one */ - seq = log_first_seq; - idx = log_first_idx; - prev = 0; - } - } - } - - if (clear) { - clear_seq = log_next_seq; - clear_idx = log_next_idx; - } - raw_spin_unlock_irq(&logbuf_lock); - - kfree(text); - return len; -} - -int do_syslog(int type, char __user *buf, int len, bool from_file) -{ - bool clear = false; - static int saved_console_loglevel = -1; - 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: /* Close log */ - break; - case SYSLOG_ACTION_OPEN: /* Open log */ - break; - case SYSLOG_ACTION_READ: /* Read from log */ - 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, - syslog_seq != log_next_seq); - if (error) - goto out; - error = syslog_print(buf, len); - break; - /* Read/clear last kernel messages */ - case SYSLOG_ACTION_READ_CLEAR: - clear = true; - /* FALL THRU */ - /* Read last kernel messages */ - 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; - } - error = syslog_print_all(buf, len, clear); - break; - /* Clear ring buffer */ - case SYSLOG_ACTION_CLEAR: - syslog_print_all(NULL, 0, true); - break; - /* 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; - /* Enable logging to console */ - case SYSLOG_ACTION_CONSOLE_ON: - if (saved_console_loglevel != -1) { - console_loglevel = saved_console_loglevel; - saved_console_loglevel = -1; - } - break; - /* 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; - /* Number of chars in the log buffer */ - case SYSLOG_ACTION_SIZE_UNREAD: - raw_spin_lock_irq(&logbuf_lock); - if (syslog_seq < log_first_seq) { - /* messages are gone, move to first one */ - syslog_seq = log_first_seq; - syslog_idx = log_first_idx; - syslog_prev = 0; - syslog_partial = 0; - } - if (from_file) { - /* - * Short-cut for poll(/"proc/kmsg") which simply checks - * for pending data, not the size; return the count of - * records, not the length. - */ - error = log_next_idx - syslog_idx; - } else { - u64 seq = syslog_seq; - u32 idx = syslog_idx; - enum log_flags prev = syslog_prev; - - error = 0; - while (seq < log_next_seq) { - struct log *msg = log_from_idx(idx); - - error += msg_print_text(msg, prev, true, NULL, 0); - idx = log_next(idx); - seq++; - prev = msg->flags; - } - error -= syslog_partial; - } - raw_spin_unlock_irq(&logbuf_lock); - break; - /* Size of the log buffer */ - 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_READER); -} - -/* - * Call the console drivers, asking them to write out - * log_buf[start] to log_buf[end - 1]. - * The console_lock must be held. - */ -static void call_console_drivers(int level, const char *text, size_t len) -{ - struct console *con; - - trace_console(text, len); - - if (level >= console_loglevel && !ignore_loglevel) - return; - if (!console_drivers) - return; - - for_each_console(con) { - if (exclusive_console && con != exclusive_console) - continue; - if (!(con->flags & CON_ENABLED)) - continue; - if (!con->write) - continue; - if (!cpu_online(smp_processor_id()) && - !(con->flags & CON_ANYTIME)) - continue; - con->write(con, text, len); - } -} - -/* - * Zap console related locks when oopsing. Only zap at most once - * every 10 seconds, to leave time for slow consoles to print a - * full oops. - */ -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(); - /* If a crash is occurring, make sure we can't deadlock */ - raw_spin_lock_init(&logbuf_lock); - /* And make sure that we print immediately */ - sema_init(&console_sem, 1); -} - -/* Check if we have any console registered that can be called early in boot. */ -static int have_callable_console(void) -{ - struct console *con; - - for_each_console(con) - if (con->flags & CON_ANYTIME) - return 1; - - return 0; -} - -/* - * 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_lock 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 console_trylock_for_printk(unsigned int cpu) - __releases(&logbuf_lock) -{ - int retval = 0, wake = 0; - - if (console_trylock()) { - 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; - wake = 1; - retval = 0; - } - } - logbuf_cpu = UINT_MAX; - if (wake) - up(&console_sem); - raw_spin_unlock(&logbuf_lock); - return retval; -} - -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(); - } - } -} - -/* - * Continuation lines are buffered, and not committed to the record buffer - * until the line is complete, or a race forces it. The line fragments - * though, are printed immediately to the consoles to ensure everything has - * reached the console in case of a kernel crash. - */ -static struct cont { - char buf[LOG_LINE_MAX]; - size_t len; /* length == 0 means unused buffer */ - size_t cons; /* bytes written to console */ - struct task_struct *owner; /* task of first print*/ - u64 ts_nsec; /* time of first print */ - u8 level; /* log level of first message */ - u8 facility; /* log level of first message */ - enum log_flags flags; /* prefix, newline flags */ - bool flushed:1; /* buffer sealed and committed */ -} cont; - -static void cont_flush(enum log_flags flags) -{ - if (cont.flushed) - return; - if (cont.len == 0) - return; - - if (cont.cons) { - /* - * If a fragment of this line was directly flushed to the - * console; wait for the console to pick up the rest of the - * line. LOG_NOCONS suppresses a duplicated output. - */ - log_store(cont.facility, cont.level, flags | LOG_NOCONS, - cont.ts_nsec, NULL, 0, cont.buf, cont.len); - cont.flags = flags; - cont.flushed = true; - } else { - /* - * If no fragment of this line ever reached the console, - * just submit it to the store and free the buffer. - */ - log_store(cont.facility, cont.level, flags, 0, - NULL, 0, cont.buf, cont.len); - cont.len = 0; - } -} - -static bool cont_add(int facility, int level, const char *text, size_t len) -{ - if (cont.len && cont.flushed) - return false; - - if (cont.len + len > sizeof(cont.buf)) { - /* the line gets too long, split it up in separate records */ - cont_flush(LOG_CONT); - return false; - } - - if (!cont.len) { - cont.facility = facility; - cont.level = level; - cont.owner = current; - cont.ts_nsec = local_clock(); - cont.flags = 0; - cont.cons = 0; - cont.flushed = false; - } - - memcpy(cont.buf + cont.len, text, len); - cont.len += len; - - if (cont.len > (sizeof(cont.buf) * 80) / 100) - cont_flush(LOG_CONT); - - return true; -} - -static size_t cont_print_text(char *text, size_t size) -{ - size_t textlen = 0; - size_t len; - - if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { - textlen += print_time(cont.ts_nsec, text); - size -= textlen; - } - - len = cont.len - cont.cons; - if (len > 0) { - if (len+1 > size) - len = size-1; - memcpy(text + textlen, cont.buf + cont.cons, len); - textlen += len; - cont.cons = cont.len; - } - - if (cont.flushed) { - if (cont.flags & LOG_NEWLINE) - text[textlen++] = '\n'; - /* got everything, release buffer */ - cont.len = 0; - } - return textlen; -} - -asmlinkage int vprintk_emit(int facility, int level, - const char *dict, size_t dictlen, - const char *fmt, va_list args) -{ - static int recursion_bug; - static char textbuf[LOG_LINE_MAX]; - char *text = textbuf; - size_t text_len; - enum log_flags lflags = 0; - unsigned long flags; - int this_cpu; - int printed_len = 0; - - boot_delay_msec(level); - printk_delay(); - - /* This stops the holder of console_sem just where we want him */ - local_irq_save(flags); - this_cpu = smp_processor_id(); - - /* - * Ouch, printk recursed into itself! - */ - if (unlikely(logbuf_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 && !lockdep_recursing(current)) { - recursion_bug = 1; - goto out_restore_irqs; - } - zap_locks(); - } - - lockdep_off(); - raw_spin_lock(&logbuf_lock); - logbuf_cpu = this_cpu; - - if (recursion_bug) { - static const char recursion_msg[] = - "BUG: recent printk recursion!"; - - recursion_bug = 0; - printed_len += strlen(recursion_msg); - /* emit KERN_CRIT message */ - log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, - NULL, 0, recursion_msg, printed_len); - } - - /* - * The printf needs to come first; we need the syslog - * prefix which might be passed-in as a parameter. - */ - text_len = vscnprintf(text, sizeof(textbuf), fmt, args); - - /* mark and strip a trailing newline */ - if (text_len && text[text_len-1] == '\n') { - text_len--; - lflags |= LOG_NEWLINE; - } - - /* strip kernel syslog prefix and extract log level or control flags */ - if (facility == 0) { - int kern_level = printk_get_level(text); - - if (kern_level) { - const char *end_of_header = printk_skip_level(text); - switch (kern_level) { - case '0' ... '7': - if (level == -1) - level = kern_level - '0'; - case 'd': /* KERN_DEFAULT */ - lflags |= LOG_PREFIX; - case 'c': /* KERN_CONT */ - break; - } - text_len -= end_of_header - text; - text = (char *)end_of_header; - } - } - -#ifdef CONFIG_EARLY_PRINTK_DIRECT - printascii(text); -#endif - - if (level == -1) - level = default_message_loglevel; - - if (dict) - lflags |= LOG_PREFIX|LOG_NEWLINE; - - if (!(lflags & LOG_NEWLINE)) { - /* - * Flush the conflicting buffer. An earlier newline was missing, - * or another task also prints continuation lines. - */ - if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) - cont_flush(LOG_NEWLINE); - - /* buffer line if possible, otherwise store it right away */ - if (!cont_add(facility, level, text, text_len)) - log_store(facility, level, lflags | LOG_CONT, 0, - dict, dictlen, text, text_len); - } else { - bool stored = false; - - /* - * If an earlier newline was missing and it was the same task, - * either merge it with the current buffer and flush, or if - * there was a race with interrupts (prefix == true) then just - * flush it out and store this line separately. - */ - if (cont.len && cont.owner == current) { - if (!(lflags & LOG_PREFIX)) - stored = cont_add(facility, level, text, text_len); - cont_flush(LOG_NEWLINE); - } - - if (!stored) - log_store(facility, level, lflags, 0, - dict, dictlen, text, text_len); - } - printed_len += text_len; - - /* - * Try to acquire and then immediately release the console semaphore. - * The release will print out buffers and wake up /dev/kmsg and syslog() - * users. - * - * The console_trylock_for_printk() function will release 'logbuf_lock' - * regardless of whether it actually gets the console semaphore or not. - */ - if (console_trylock_for_printk(this_cpu)) - console_unlock(); - - lockdep_on(); -out_restore_irqs: - local_irq_restore(flags); - - return printed_len; -} -EXPORT_SYMBOL(vprintk_emit); - -asmlinkage int vprintk(const char *fmt, va_list args) -{ - return vprintk_emit(0, -1, NULL, 0, fmt, args); -} -EXPORT_SYMBOL(vprintk); - -asmlinkage int printk_emit(int facility, int level, - const char *dict, size_t dictlen, - const char *fmt, ...) -{ - va_list args; - int r; - - va_start(args, fmt); - r = vprintk_emit(facility, level, dict, dictlen, fmt, args); - va_end(args); - - return r; -} -EXPORT_SYMBOL(printk_emit); - -/** - * 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_lock. 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 notice the new output in console_unlock(); and will - * send it to the consoles before releasing the lock. - * - * 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) - * - * See the vsnprintf() documentation for format string extensions over C99. - */ -asmlinkage int printk(const char *fmt, ...) -{ - va_list args; - int r; - -#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_emit(0, -1, NULL, 0, fmt, args); - va_end(args); - - return r; -} -EXPORT_SYMBOL(printk); - -#else /* CONFIG_PRINTK */ - -#define LOG_LINE_MAX 0 -#define PREFIX_MAX 0 -#define LOG_LINE_MAX 0 -static u64 syslog_seq; -static u32 syslog_idx; -static u64 console_seq; -static u32 console_idx; -static enum log_flags syslog_prev; -static u64 log_first_seq; -static u32 log_first_idx; -static u64 log_next_seq; -static enum log_flags console_prev; -static struct cont { - size_t len; - size_t cons; - u8 level; - bool flushed:1; -} cont; -static struct log *log_from_idx(u32 idx) { return NULL; } -static u32 log_next(u32 idx) { return 0; } -static void call_console_drivers(int level, const char *text, size_t len) {} -static size_t msg_print_text(const struct log *msg, enum log_flags prev, - bool syslog, char *buf, size_t size) { return 0; } -static size_t cont_print_text(char *text, size_t size) { return 0; } - -#endif /* CONFIG_PRINTK */ - -#ifdef CONFIG_EARLY_PRINTK -struct console *early_console; - -void early_vprintk(const char *fmt, va_list ap) -{ - if (early_console) { - char buf[512]; - int n = vscnprintf(buf, sizeof(buf), fmt, ap); - - early_console->write(early_console, buf, n); - } -} - -asmlinkage void early_printk(const char *fmt, ...) -{ - va_list ap; - - va_start(ap, fmt); - early_vprintk(fmt, ap); - va_end(ap); -} -#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 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(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); - -/** - * 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 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; - } - /* not found */ - 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); -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"); - -/** - * suspend_console - suspend the console subsystem - * - * This disables printk() while we go into suspend states - */ -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(); -} - -/** - * console_cpu_notify - print deferred console messages after CPU hotplug - * @self: notifier struct - * @action: CPU hotplug event - * @hcpu: unused - * - * If printk() is called from a CPU that is not online yet, the messages - * will be spooled but will not show up on the console. This function is - * called when a new CPU comes online (or fails to come up), and ensures - * that any such output gets printed. - */ -static int __cpuinit console_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - switch (action) { - case CPU_ONLINE: - case CPU_DEAD: - case CPU_DOWN_FAILED: - case CPU_UP_CANCELED: - console_lock(); - console_unlock(); - } - return NOTIFY_OK; -} - -/** - * console_lock - lock the console system for exclusive use. - * - * Acquires a lock which guarantees that the caller has - * exclusive access to the console system and the console_drivers list. - * - * Can sleep, returns nothing. - */ -void console_lock(void) -{ - might_sleep(); - - down(&console_sem); - if (console_suspended) - return; - console_locked = 1; - console_may_schedule = 1; - mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); -} -EXPORT_SYMBOL(console_lock); - -/** - * console_trylock - try to lock the console system for exclusive use. - * - * Tried to acquire a lock which guarantees that the caller has - * exclusive access to the console system and the console_drivers list. - * - * returns 1 on success, and 0 on failure to acquire the 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; - mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_); - return 1; -} -EXPORT_SYMBOL(console_trylock); - -int is_console_locked(void) -{ - return console_locked; -} - -static void console_cont_flush(char *text, size_t size) -{ - unsigned long flags; - size_t len; - - raw_spin_lock_irqsave(&logbuf_lock, flags); - - if (!cont.len) - goto out; - - /* - * We still queue earlier records, likely because the console was - * busy. The earlier ones need to be printed before this one, we - * did not flush any fragment so far, so just let it queue up. - */ - if (console_seq < log_next_seq && !cont.cons) - goto out; - - len = cont_print_text(text, size); - raw_spin_unlock(&logbuf_lock); - stop_critical_timings(); - call_console_drivers(cont.level, text, len); - start_critical_timings(); - local_irq_restore(flags); - return; -out: - raw_spin_unlock_irqrestore(&logbuf_lock, flags); -} - -/** - * console_unlock - unlock the console system - * - * Releases the console_lock which the caller holds on the console system - * and the console driver list. - * - * While the console_lock was held, console output may have been buffered - * by printk(). If this is the case, console_unlock(); emits - * the output prior to releasing the lock. - * - * If there is output waiting, we wake /dev/kmsg and syslog() users. - * - * console_unlock(); may be called from any context. - */ -void console_unlock(void) -{ - static char text[LOG_LINE_MAX + PREFIX_MAX]; - static u64 seen_seq; - unsigned long flags; - bool wake_klogd = false; - bool retry; - - if (console_suspended) { - up(&console_sem); - return; - } - - console_may_schedule = 0; - - /* flush buffered message fragment immediately to console */ - console_cont_flush(text, sizeof(text)); -again: - for (;;) { - struct log *msg; - size_t len; - int level; - - raw_spin_lock_irqsave(&logbuf_lock, flags); - if (seen_seq != log_next_seq) { - wake_klogd = true; - seen_seq = log_next_seq; - } - - if (console_seq < log_first_seq) { - /* messages are gone, move to first one */ - console_seq = log_first_seq; - console_idx = log_first_idx; - console_prev = 0; - } -skip: - if (console_seq == log_next_seq) - break; - - msg = log_from_idx(console_idx); - if (msg->flags & LOG_NOCONS) { - /* - * Skip record we have buffered and already printed - * directly to the console when we received it. - */ - console_idx = log_next(console_idx); - console_seq++; - /* - * We will get here again when we register a new - * CON_PRINTBUFFER console. Clear the flag so we - * will properly dump everything later. - */ - msg->flags &= ~LOG_NOCONS; - console_prev = msg->flags; - goto skip; - } - - level = msg->level; - len = msg_print_text(msg, console_prev, false, - text, sizeof(text)); - console_idx = log_next(console_idx); - console_seq++; - console_prev = msg->flags; - raw_spin_unlock(&logbuf_lock); - - stop_critical_timings(); /* don't trace print latency */ - call_console_drivers(level, text, len); - start_critical_timings(); - local_irq_restore(flags); - } - console_locked = 0; - mutex_release(&console_lock_dep_map, 1, _RET_IP_); - - /* Release the exclusive_console once it is used */ - if (unlikely(exclusive_console)) - exclusive_console = NULL; - - raw_spin_unlock(&logbuf_lock); - - up(&console_sem); - - /* - * Someone could have filled up the buffer again, so re-check if there's - * something to flush. In case we cannot trylock the console_sem again, - * there's a new owner and the console_unlock() from them will do the - * flush, no worries. - */ - raw_spin_lock(&logbuf_lock); - retry = console_seq != log_next_seq; - raw_spin_unlock_irqrestore(&logbuf_lock, flags); - - if (retry && console_trylock()) - goto again; - - if (wake_klogd) - wake_up_klogd(); -} -EXPORT_SYMBOL(console_unlock); - -/** - * 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 - * so here. - * - * Must be called within console_lock();. - */ -void __sched console_conditional_schedule(void) -{ - if (console_may_schedule) - cond_resched(); -} -EXPORT_SYMBOL(console_conditional_schedule); - -void console_unblank(void) -{ - struct console *c; - - /* - * console_unblank can no longer be called in interrupt context unless - * oops_in_progress is set to 1.. - */ - 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(); -} - -/* - * 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; - - console_lock(); - for_each_console(c) { - if (!c->device) - continue; - driver = c->device(c, index); - if (driver) - break; - } - console_unlock(); - 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) -{ - 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); - -/* - * The console driver calls this routine during kernel initialization - * 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 *newcon) -{ - int i; - unsigned long flags; - struct console *bcon = NULL; - - /* - * 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 (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; - } - } - } - - /* - * See if this console matches one we selected on - * the command line. - */ - 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 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. - */ - 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) { - /* - * console_unlock(); will print out the buffered messages - * for us. - */ - raw_spin_lock_irqsave(&logbuf_lock, flags); - console_seq = syslog_seq; - console_idx = syslog_idx; - console_prev = syslog_prev; - raw_spin_unlock_irqrestore(&logbuf_lock, flags); - /* - * We're about to replay the log buffer. Only do this to the - * just-registered console to avoid excessive message spam to - * the already-registered consoles. - */ - exclusive_console = newcon; - } - console_unlock(); - console_sysfs_notify(); - - /* - * 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) && - !keep_bootcon) { - /* 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); - -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 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 && 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 -/* - * Delayed printk version, for scheduler-internal messages: - */ -#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(); -} - -int printk_sched(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; -} - -/* - * 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(const char *func) -{ - return ___ratelimit(&printk_ratelimit_state, func); -} -EXPORT_SYMBOL(__printk_ratelimit); - -/** - * printk_timed_ratelimit - caller-controlled printk ratelimiting - * @caller_jiffies: pointer to caller's state - * @interval_msecs: minimum interval between prints - * - * printk_timed_ratelimit() returns true if more than @interval_msecs - * milliseconds have elapsed since the last time printk_timed_ratelimit() - * returned true. - */ -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); - -/** - * 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_rcu(&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_rcu(&dumper->list); - err = 0; - } - spin_unlock_irqrestore(&dump_list_lock, flags); - synchronize_rcu(); - - return err; -} -EXPORT_SYMBOL_GPL(kmsg_dump_unregister); - -static bool always_kmsg_dump; -module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); - -/** - * kmsg_dump - dump kernel log to kernel message dumpers. - * @reason: the reason (oops, panic etc) for dumping - * - * Call each of the registered dumper's dump() callback, which can - * retrieve the kmsg records with kmsg_dump_get_line() or - * kmsg_dump_get_buffer(). - */ -void kmsg_dump(enum kmsg_dump_reason reason) -{ - struct kmsg_dumper *dumper; - unsigned long flags; - - if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) - return; - - rcu_read_lock(); - list_for_each_entry_rcu(dumper, &dump_list, list) { - if (dumper->max_reason && reason > dumper->max_reason) - continue; - - /* initialize iterator with data about the stored records */ - dumper->active = true; - - raw_spin_lock_irqsave(&logbuf_lock, flags); - dumper->cur_seq = clear_seq; - dumper->cur_idx = clear_idx; - dumper->next_seq = log_next_seq; - dumper->next_idx = log_next_idx; - raw_spin_unlock_irqrestore(&logbuf_lock, flags); - - /* invoke dumper which will iterate over records */ - dumper->dump(dumper, reason); - - /* reset iterator */ - dumper->active = false; - } - rcu_read_unlock(); -} - -/** - * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) - * @dumper: registered kmsg dumper - * @syslog: include the "<4>" prefixes - * @line: buffer to copy the line to - * @size: maximum size of the buffer - * @len: length of line placed into buffer - * - * Start at the beginning of the kmsg buffer, with the oldest kmsg - * record, and copy one record into the provided buffer. - * - * Consecutive calls will return the next available record moving - * towards the end of the buffer with the youngest messages. - * - * A return value of FALSE indicates that there are no more records to - * read. - * - * The function is similar to kmsg_dump_get_line(), but grabs no locks. - */ -bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, - char *line, size_t size, size_t *len) -{ - struct log *msg; - size_t l = 0; - bool ret = false; - - if (!dumper->active) - goto out; - - if (dumper->cur_seq < log_first_seq) { - /* messages are gone, move to first available one */ - dumper->cur_seq = log_first_seq; - dumper->cur_idx = log_first_idx; - } - - /* last entry */ - if (dumper->cur_seq >= log_next_seq) - goto out; - - msg = log_from_idx(dumper->cur_idx); - l = msg_print_text(msg, 0, syslog, line, size); - - dumper->cur_idx = log_next(dumper->cur_idx); - dumper->cur_seq++; - ret = true; -out: - if (len) - *len = l; - return ret; -} - -/** - * kmsg_dump_get_line - retrieve one kmsg log line - * @dumper: registered kmsg dumper - * @syslog: include the "<4>" prefixes - * @line: buffer to copy the line to - * @size: maximum size of the buffer - * @len: length of line placed into buffer - * - * Start at the beginning of the kmsg buffer, with the oldest kmsg - * record, and copy one record into the provided buffer. - * - * Consecutive calls will return the next available record moving - * towards the end of the buffer with the youngest messages. - * - * A return value of FALSE indicates that there are no more records to - * read. - */ -bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, - char *line, size_t size, size_t *len) -{ - unsigned long flags; - bool ret; - - raw_spin_lock_irqsave(&logbuf_lock, flags); - ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); - raw_spin_unlock_irqrestore(&logbuf_lock, flags); - - return ret; -} -EXPORT_SYMBOL_GPL(kmsg_dump_get_line); - -/** - * kmsg_dump_get_buffer - copy kmsg log lines - * @dumper: registered kmsg dumper - * @syslog: include the "<4>" prefixes - * @buf: buffer to copy the line to - * @size: maximum size of the buffer - * @len: length of line placed into buffer - * - * Start at the end of the kmsg buffer and fill the provided buffer - * with as many of the the *youngest* kmsg records that fit into it. - * If the buffer is large enough, all available kmsg records will be - * copied with a single call. - * - * Consecutive calls will fill the buffer with the next block of - * available older records, not including the earlier retrieved ones. - * - * A return value of FALSE indicates that there are no more records to - * read. - */ -bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, - char *buf, size_t size, size_t *len) -{ - unsigned long flags; - u64 seq; - u32 idx; - u64 next_seq; - u32 next_idx; - enum log_flags prev; - size_t l = 0; - bool ret = false; - - if (!dumper->active) - goto out; - - raw_spin_lock_irqsave(&logbuf_lock, flags); - if (dumper->cur_seq < log_first_seq) { - /* messages are gone, move to first available one */ - dumper->cur_seq = log_first_seq; - dumper->cur_idx = log_first_idx; - } - - /* last entry */ - if (dumper->cur_seq >= dumper->next_seq) { - raw_spin_unlock_irqrestore(&logbuf_lock, flags); - goto out; - } - - /* calculate length of entire buffer */ - seq = dumper->cur_seq; - idx = dumper->cur_idx; - prev = 0; - while (seq < dumper->next_seq) { - struct log *msg = log_from_idx(idx); - - l += msg_print_text(msg, prev, true, NULL, 0); - idx = log_next(idx); - seq++; - prev = msg->flags; - } - - /* move first record forward until length fits into the buffer */ - seq = dumper->cur_seq; - idx = dumper->cur_idx; - prev = 0; - while (l > size && seq < dumper->next_seq) { - struct log *msg = log_from_idx(idx); - - l -= msg_print_text(msg, prev, true, NULL, 0); - idx = log_next(idx); - seq++; - prev = msg->flags; - } - - /* last message in next interation */ - next_seq = seq; - next_idx = idx; - - l = 0; - prev = 0; - while (seq < dumper->next_seq) { - struct log *msg = log_from_idx(idx); - - l += msg_print_text(msg, prev, syslog, buf + l, size - l); - idx = log_next(idx); - seq++; - prev = msg->flags; - } - - dumper->next_seq = next_seq; - dumper->next_idx = next_idx; - ret = true; - raw_spin_unlock_irqrestore(&logbuf_lock, flags); -out: - if (len) - *len = l; - return ret; -} -EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); - -/** - * kmsg_dump_rewind_nolock - reset the interator (unlocked version) - * @dumper: registered kmsg dumper - * - * Reset the dumper's iterator so that kmsg_dump_get_line() and - * kmsg_dump_get_buffer() can be called again and used multiple - * times within the same dumper.dump() callback. - * - * The function is similar to kmsg_dump_rewind(), but grabs no locks. - */ -void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) -{ - dumper->cur_seq = clear_seq; - dumper->cur_idx = clear_idx; - dumper->next_seq = log_next_seq; - dumper->next_idx = log_next_idx; -} - -/** - * kmsg_dump_rewind - reset the interator - * @dumper: registered kmsg dumper - * - * Reset the dumper's iterator so that kmsg_dump_get_line() and - * kmsg_dump_get_buffer() can be called again and used multiple - * times within the same dumper.dump() callback. - */ -void kmsg_dump_rewind(struct kmsg_dumper *dumper) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&logbuf_lock, flags); - kmsg_dump_rewind_nolock(dumper); - raw_spin_unlock_irqrestore(&logbuf_lock, flags); -} -EXPORT_SYMBOL_GPL(kmsg_dump_rewind); - -static char dump_stack_arch_desc_str[128]; - -/** - * dump_stack_set_arch_desc - set arch-specific str to show with task dumps - * @fmt: printf-style format string - * @...: arguments for the format string - * - * The configured string will be printed right after utsname during task - * dumps. Usually used to add arch-specific system identifiers. If an - * arch wants to make use of such an ID string, it should initialize this - * as soon as possible during boot. - */ -void __init dump_stack_set_arch_desc(const char *fmt, ...) -{ - va_list args; - - va_start(args, fmt); - vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), - fmt, args); - va_end(args); -} - -/** - * dump_stack_print_info - print generic debug info for dump_stack() - * @log_lvl: log level - * - * Arch-specific dump_stack() implementations can use this function to - * print out the same debug information as the generic dump_stack(). - */ -void dump_stack_print_info(const char *log_lvl) -{ - printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", - log_lvl, raw_smp_processor_id(), current->pid, current->comm, - print_tainted(), init_utsname()->release, - (int)strcspn(init_utsname()->version, " "), - init_utsname()->version); - - if (dump_stack_arch_desc_str[0] != '\0') - printk("%sHardware name: %s\n", - log_lvl, dump_stack_arch_desc_str); - - print_worker_info(log_lvl, current); -} - -/** - * show_regs_print_info - print generic debug info for show_regs() - * @log_lvl: log level - * - * show_regs() implementations can use this function to print out generic - * debug information. - */ -void show_regs_print_info(const char *log_lvl) -{ - dump_stack_print_info(log_lvl); - - printk("%stask: %p ti: %p task.ti: %p\n", - log_lvl, current, current_thread_info(), - task_thread_info(current)); -} - -#endif |