diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/printk/printk.c | 66 |
1 files changed, 58 insertions, 8 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 51ce4f1838b3..ae980dc3ac1e 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -85,6 +85,18 @@ static struct lockdep_map console_lock_dep_map = { #endif /* + * Number of registered extended console drivers. + * + * If extended consoles are present, in-kernel cont reassembly is disabled + * and each fragment is stored as a separate log entry with proper + * continuation flag so that every emitted message has full metadata. This + * doesn't change the result for regular consoles or /proc/kmsg. For + * /dev/kmsg, as long as the reader concatenates messages according to + * consecutive continuation flags, the end result should be the same too. + */ +static int nr_ext_console_drivers; + +/* * Helper macros to handle lockdep when locking/unlocking console_sem. We use * macros instead of functions so that _RET_IP_ contains useful information. */ @@ -195,7 +207,7 @@ static int console_may_schedule; * 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" + * "<level>,<sequnum>,<timestamp>,<contflag>;<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 @@ -1417,7 +1429,9 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) * 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) +static void call_console_drivers(int level, + const char *ext_text, size_t ext_len, + const char *text, size_t len) { struct console *con; @@ -1438,7 +1452,10 @@ static void call_console_drivers(int level, const char *text, size_t len) if (!cpu_online(smp_processor_id()) && !(con->flags & CON_ANYTIME)) continue; - con->write(con, text, len); + if (con->flags & CON_EXTENDED) + con->write(con, ext_text, ext_len); + else + con->write(con, text, len); } } @@ -1581,8 +1598,12 @@ 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 */ + /* + * If ext consoles are present, flush and skip in-kernel + * continuation. See nr_ext_console_drivers definition. Also, if + * the line gets too long, split it up in separate records. + */ + if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) { cont_flush(LOG_CONT); return false; } @@ -1917,9 +1938,19 @@ static struct cont { u8 level; bool flushed:1; } cont; +static char *log_text(const struct printk_log *msg) { return NULL; } +static char *log_dict(const struct printk_log *msg) { return NULL; } static struct printk_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 ssize_t msg_print_ext_header(char *buf, size_t size, + struct printk_log *msg, u64 seq, + enum log_flags prev_flags) { return 0; } +static ssize_t msg_print_ext_body(char *buf, size_t size, + char *dict, size_t dict_len, + char *text, size_t text_len) { return 0; } +static void call_console_drivers(int level, + const char *ext_text, size_t ext_len, + const char *text, size_t len) {} static size_t msg_print_text(const struct printk_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; } @@ -2172,7 +2203,7 @@ static void console_cont_flush(char *text, size_t size) len = cont_print_text(text, size); raw_spin_unlock(&logbuf_lock); stop_critical_timings(); - call_console_drivers(cont.level, text, len); + call_console_drivers(cont.level, NULL, 0, text, len); start_critical_timings(); local_irq_restore(flags); return; @@ -2196,6 +2227,7 @@ out: */ void console_unlock(void) { + static char ext_text[CONSOLE_EXT_LOG_MAX]; static char text[LOG_LINE_MAX + PREFIX_MAX]; static u64 seen_seq; unsigned long flags; @@ -2214,6 +2246,7 @@ void console_unlock(void) again: for (;;) { struct printk_log *msg; + size_t ext_len = 0; size_t len; int level; @@ -2259,13 +2292,22 @@ skip: level = msg->level; len += msg_print_text(msg, console_prev, false, text + len, sizeof(text) - len); + if (nr_ext_console_drivers) { + ext_len = msg_print_ext_header(ext_text, + sizeof(ext_text), + msg, console_seq, console_prev); + ext_len += msg_print_ext_body(ext_text + ext_len, + sizeof(ext_text) - ext_len, + log_dict(msg), msg->dict_len, + log_text(msg), msg->text_len); + } 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); + call_console_drivers(level, ext_text, ext_len, text, len); start_critical_timings(); local_irq_restore(flags); } @@ -2521,6 +2563,11 @@ void register_console(struct console *newcon) newcon->next = console_drivers->next; console_drivers->next = newcon; } + + if (newcon->flags & CON_EXTENDED) + if (!nr_ext_console_drivers++) + pr_info("printk: continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n"); + if (newcon->flags & CON_PRINTBUFFER) { /* * console_unlock(); will print out the buffered messages @@ -2593,6 +2640,9 @@ int unregister_console(struct console *console) } } + if (!res && (console->flags & CON_EXTENDED)) + nr_ext_console_drivers--; + /* * If this isn't the last console and it has CON_CONSDEV set, we * need to set it on the next preferred console. |