diff options
Diffstat (limited to 'kernel/printk/printk.c')
| -rw-r--r-- | kernel/printk/printk.c | 60 |
1 files changed, 43 insertions, 17 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 3dea8bbaf402..dec5355c5b5b 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -394,6 +394,9 @@ static struct latched_seq clear_seq = { /* the maximum size of a formatted record (i.e. with prefix added per line) */ #define CONSOLE_LOG_MAX 1024 +/* the maximum size for a dropped text message */ +#define DROPPED_TEXT_MAX 64 + /* the maximum size allowed to be reserved for a record */ #define LOG_LINE_MAX (CONSOLE_LOG_MAX - PREFIX_MAX) @@ -1923,18 +1926,18 @@ static int console_trylock_spinning(void) /* * Call the specified console driver, asking it to write out the specified - * text and length. For non-extended consoles, if any records have been + * text and length. If @dropped_text is non-NULL and any records have been * dropped, a dropped message will be written out first. */ -static void call_console_driver(struct console *con, const char *text, size_t len) +static void call_console_driver(struct console *con, const char *text, size_t len, + char *dropped_text) { - static char dropped_text[64]; size_t dropped_len; trace_console_rcuidle(text, len); - if (con->dropped && !(con->flags & CON_EXTENDED)) { - dropped_len = snprintf(dropped_text, sizeof(dropped_text), + if (con->dropped && dropped_text) { + dropped_len = snprintf(dropped_text, DROPPED_TEXT_MAX, "** %lu printk messages dropped **\n", con->dropped); con->dropped = 0; @@ -2296,6 +2299,7 @@ EXPORT_SYMBOL(_printk); #else /* CONFIG_PRINTK */ #define CONSOLE_LOG_MAX 0 +#define DROPPED_TEXT_MAX 0 #define printk_time false #define prb_read_valid(rb, seq, r) false @@ -2319,7 +2323,10 @@ static ssize_t msg_print_ext_body(char *buf, size_t size, struct dev_printk_info *dev_info) { return 0; } static void console_lock_spinning_enable(void) { } static int console_lock_spinning_disable_and_check(void) { return 0; } -static void call_console_driver(struct console *con, const char *text, size_t len) { } +static void call_console_driver(struct console *con, const char *text, size_t len, + char *dropped_text) +{ +} static bool suppress_message_printing(int level) { return false; } #endif /* CONFIG_PRINTK */ @@ -2644,6 +2651,14 @@ static void __console_unlock(void) * Print one record for the given console. The record printed is whatever * record is the next available record for the given console. * + * @text is a buffer of size CONSOLE_LOG_MAX. + * + * If extended messages should be printed, @ext_text is a buffer of size + * CONSOLE_EXT_LOG_MAX. Otherwise @ext_text must be NULL. + * + * If dropped messages should be printed, @dropped_text is a buffer of size + * DROPPED_TEXT_MAX. Otherwise @dropped_text must be NULL. + * * @handover will be set to true if a printk waiter has taken over the * console_lock, in which case the caller is no longer holding the * console_lock. Otherwise it is set to false. @@ -2653,10 +2668,9 @@ static void __console_unlock(void) * * Requires the console_lock. */ -static bool console_emit_next_record(struct console *con, bool *handover) +static bool console_emit_next_record(struct console *con, char *text, char *ext_text, + char *dropped_text, bool *handover) { - static char ext_text[CONSOLE_EXT_LOG_MAX]; - static char text[CONSOLE_LOG_MAX]; static int panic_console_dropped; struct printk_info info; struct printk_record r; @@ -2664,7 +2678,7 @@ static bool console_emit_next_record(struct console *con, bool *handover) char *write_text; size_t len; - prb_rec_init_rd(&r, &info, text, sizeof(text)); + prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX); *handover = false; @@ -2686,13 +2700,13 @@ static bool console_emit_next_record(struct console *con, bool *handover) goto skip; } - if (con->flags & CON_EXTENDED) { - write_text = &ext_text[0]; - len = info_print_ext_header(ext_text, sizeof(ext_text), r.info); - len += msg_print_ext_body(ext_text + len, sizeof(ext_text) - len, + if (ext_text) { + write_text = ext_text; + len = info_print_ext_header(ext_text, CONSOLE_EXT_LOG_MAX, r.info); + len += msg_print_ext_body(ext_text + len, CONSOLE_EXT_LOG_MAX - len, &r.text_buf[0], r.info->text_len, &r.info->dev_info); } else { - write_text = &text[0]; + write_text = text; len = record_print_text(&r, console_msg_format & MSG_FORMAT_SYSLOG, printk_time); } @@ -2710,7 +2724,7 @@ static bool console_emit_next_record(struct console *con, bool *handover) console_lock_spinning_enable(); stop_critical_timings(); /* don't trace print latency */ - call_console_driver(con, write_text, len); + call_console_driver(con, write_text, len, dropped_text); start_critical_timings(); con->seq++; @@ -2746,6 +2760,9 @@ skip: */ static bool console_flush_all(bool do_cond_resched, u64 *next_seq, bool *handover) { + static char dropped_text[DROPPED_TEXT_MAX]; + static char ext_text[CONSOLE_EXT_LOG_MAX]; + static char text[CONSOLE_LOG_MAX]; bool any_usable = false; struct console *con; bool any_progress; @@ -2763,7 +2780,16 @@ static bool console_flush_all(bool do_cond_resched, u64 *next_seq, bool *handove continue; any_usable = true; - progress = console_emit_next_record(con, handover); + if (con->flags & CON_EXTENDED) { + /* Extended consoles do not print "dropped messages". */ + progress = console_emit_next_record(con, &text[0], + &ext_text[0], NULL, + handover); + } else { + progress = console_emit_next_record(con, &text[0], + NULL, &dropped_text[0], + handover); + } if (*handover) return false; |