diff options
Diffstat (limited to 'kernel/printk/printk.c')
| -rw-r--r-- | kernel/printk/printk.c | 66 |
1 files changed, 51 insertions, 15 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 80910bc3470c..1eea80d0648e 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -523,7 +523,7 @@ static struct latched_seq clear_seq = { /* record buffer */ #define LOG_ALIGN __alignof__(unsigned long) #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) -#define LOG_BUF_LEN_MAX (u32)(1 << 31) +#define LOG_BUF_LEN_MAX ((u32)1 << 31) static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); static char *log_buf = __log_buf; static u32 log_buf_len = __LOG_BUF_LEN; @@ -2375,6 +2375,22 @@ void printk_legacy_allow_panic_sync(void) } } +bool __read_mostly debug_non_panic_cpus; + +#ifdef CONFIG_PRINTK_CALLER +static int __init debug_non_panic_cpus_setup(char *str) +{ + debug_non_panic_cpus = true; + pr_info("allow messages from non-panic CPUs in panic()\n"); + + return 0; +} +early_param("debug_non_panic_cpus", debug_non_panic_cpus_setup); +module_param(debug_non_panic_cpus, bool, 0644); +MODULE_PARM_DESC(debug_non_panic_cpus, + "allow messages from non-panic CPUs in panic()"); +#endif + asmlinkage int vprintk_emit(int facility, int level, const struct dev_printk_info *dev_info, const char *fmt, va_list args) @@ -2391,7 +2407,9 @@ asmlinkage int vprintk_emit(int facility, int level, * non-panic CPUs are generating any messages, they will be * silently dropped. */ - if (other_cpu_in_panic() && !panic_triggering_all_cpu_backtrace) + if (other_cpu_in_panic() && + !debug_non_panic_cpus && + !panic_triggering_all_cpu_backtrace) return 0; printk_get_console_flush_type(&ft); @@ -2461,7 +2479,6 @@ asmlinkage __visible int _printk(const char *fmt, ...) } EXPORT_SYMBOL(_printk); -static bool pr_flush(int timeout_ms, bool reset_on_progress); static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress); #else /* CONFIG_PRINTK */ @@ -2474,7 +2491,6 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre static u64 syslog_seq; -static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; } static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; } #endif /* CONFIG_PRINTK */ @@ -2733,11 +2749,11 @@ module_param_named(console_no_auto_verbose, printk_console_no_auto_verbose, bool MODULE_PARM_DESC(console_no_auto_verbose, "Disable console loglevel raise to highest on oops/panic/etc"); /** - * suspend_console - suspend the console subsystem + * console_suspend_all - suspend the console subsystem * * This disables printk() while we go into suspend states */ -void suspend_console(void) +void console_suspend_all(void) { struct console *con; @@ -2760,7 +2776,7 @@ void suspend_console(void) synchronize_srcu(&console_srcu); } -void resume_console(void) +void console_resume_all(void) { struct console_flush_type ft; struct console *con; @@ -3342,7 +3358,12 @@ void console_unblank(void) */ cookie = console_srcu_read_lock(); for_each_console_srcu(c) { - if ((console_srcu_read_flags(c) & CON_ENABLED) && c->unblank) { + short flags = console_srcu_read_flags(c); + + if (flags & CON_SUSPENDED) + continue; + + if ((flags & CON_ENABLED) && c->unblank) { found_unblank = true; break; } @@ -3379,7 +3400,12 @@ void console_unblank(void) cookie = console_srcu_read_lock(); for_each_console_srcu(c) { - if ((console_srcu_read_flags(c) & CON_ENABLED) && c->unblank) + short flags = console_srcu_read_flags(c); + + if (flags & CON_SUSPENDED) + continue; + + if ((flags & CON_ENABLED) && c->unblank) c->unblank(); } console_srcu_read_unlock(cookie); @@ -3497,10 +3523,10 @@ struct tty_driver *console_device(int *index) /* * Prevent further output on the passed console device so that (for example) - * serial drivers can disable console output before suspending a port, and can + * serial drivers can suspend console output before suspending a port, and can * re-enable output afterwards. */ -void console_stop(struct console *console) +void console_suspend(struct console *console) { __pr_flush(console, 1000, true); console_list_lock(); @@ -3515,9 +3541,9 @@ void console_stop(struct console *console) */ synchronize_srcu(&console_srcu); } -EXPORT_SYMBOL(console_stop); +EXPORT_SYMBOL(console_suspend); -void console_start(struct console *console) +void console_resume(struct console *console) { struct console_flush_type ft; bool is_nbcon; @@ -3542,7 +3568,7 @@ void console_start(struct console *console) __pr_flush(console, 1000, true); } -EXPORT_SYMBOL(console_start); +EXPORT_SYMBOL(console_resume); #ifdef CONFIG_PRINTK static int unregister_console_locked(struct console *console); @@ -4277,6 +4303,11 @@ void __init console_init(void) initcall_t call; initcall_entry_t *ce; +#ifdef CONFIG_NULL_TTY_DEFAULT_CONSOLE + if (!console_set_on_cmdline) + add_preferred_console("ttynull", 0, NULL); +#endif + /* Setup the default TTY line discipline. */ n_tty_init(); @@ -4466,7 +4497,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre * Context: Process context. May sleep while acquiring console lock. * Return: true if all usable printers are caught up. */ -static bool pr_flush(int timeout_ms, bool reset_on_progress) +bool pr_flush(int timeout_ms, bool reset_on_progress) { return __pr_flush(NULL, timeout_ms, reset_on_progress); } @@ -4922,6 +4953,11 @@ void console_try_replay_all(void) static atomic_t printk_cpu_sync_owner = ATOMIC_INIT(-1); static atomic_t printk_cpu_sync_nested = ATOMIC_INIT(0); +bool is_printk_cpu_sync_owner(void) +{ + return (atomic_read(&printk_cpu_sync_owner) == raw_smp_processor_id()); +} + /** * __printk_cpu_sync_wait() - Busy wait until the printk cpu-reentrant * spinning lock is not owned by any CPU. |