diff options
Diffstat (limited to 'include/linux/printk.h')
| -rw-r--r-- | include/linux/printk.h | 173 |
1 files changed, 136 insertions, 37 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h index e834d78f0478..85b656f82d75 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -2,7 +2,7 @@ #ifndef __KERNEL_PRINTK__ #define __KERNEL_PRINTK__ -#include <stdarg.h> +#include <linux/stdarg.h> #include <linux/init.h> #include <linux/kern_levels.h> #include <linux/linkage.h> @@ -70,16 +70,7 @@ extern int console_printk[]; #define minimum_console_loglevel (console_printk[2]) #define default_console_loglevel (console_printk[3]) -static inline void console_silent(void) -{ - console_loglevel = CONSOLE_LOGLEVEL_SILENT; -} - -static inline void console_verbose(void) -{ - if (console_loglevel) - console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; -} +extern void console_verbose(void); /* strlen("ratelimit") + 1 */ #define DEVKMSG_STR_MAX_SIZE 10 @@ -150,18 +141,6 @@ static inline __printf(1, 2) __cold void early_printk(const char *s, ...) { } #endif -#ifdef CONFIG_PRINTK_NMI -extern void printk_nmi_enter(void); -extern void printk_nmi_exit(void); -extern void printk_nmi_direct_enter(void); -extern void printk_nmi_direct_exit(void); -#else -static inline void printk_nmi_enter(void) { } -static inline void printk_nmi_exit(void) { } -static inline void printk_nmi_direct_enter(void) { } -static inline void printk_nmi_direct_exit(void) { } -#endif /* PRINTK_NMI */ - struct dev_printk_info; #ifdef CONFIG_PRINTK @@ -174,12 +153,22 @@ asmlinkage __printf(1, 0) int vprintk(const char *fmt, va_list args); asmlinkage __printf(1, 2) __cold -int printk(const char *fmt, ...); +int _printk(const char *fmt, ...); /* * Special printk facility for scheduler/timekeeping use only, _DO_NOT_USE_ ! */ -__printf(1, 2) __cold int printk_deferred(const char *fmt, ...); +__printf(1, 2) __cold int _printk_deferred(const char *fmt, ...); + +extern void __printk_safe_enter(void); +extern void __printk_safe_exit(void); +/* + * The printk_deferred_enter/exit macros are available only as a hack for + * some code paths that need to defer all printk console printing. Interrupts + * must be disabled for the deferred duration. + */ +#define printk_deferred_enter __printk_safe_enter +#define printk_deferred_exit __printk_safe_exit /* * Please don't use printk_ratelimit(), because it shares ratelimiting state @@ -209,8 +198,6 @@ void dump_stack_print_info(const char *log_lvl); void show_regs_print_info(const char *log_lvl); extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; extern asmlinkage void dump_stack(void) __cold; -extern void printk_safe_flush(void); -extern void printk_safe_flush_on_panic(void); #else static inline __printf(1, 0) int vprintk(const char *s, va_list args) @@ -218,15 +205,24 @@ int vprintk(const char *s, va_list args) return 0; } static inline __printf(1, 2) __cold -int printk(const char *s, ...) +int _printk(const char *s, ...) { return 0; } static inline __printf(1, 2) __cold -int printk_deferred(const char *s, ...) +int _printk_deferred(const char *s, ...) { return 0; } + +static inline void printk_deferred_enter(void) +{ +} + +static inline void printk_deferred_exit(void) +{ +} + static inline int printk_ratelimit(void) { return 0; @@ -278,14 +274,6 @@ static inline void dump_stack_lvl(const char *log_lvl) static inline void dump_stack(void) { } - -static inline void printk_safe_flush(void) -{ -} - -static inline void printk_safe_flush_on_panic(void) -{ -} #endif #ifdef CONFIG_SMP @@ -348,6 +336,117 @@ extern int kptr_restrict; #define pr_fmt(fmt) fmt #endif +struct module; + +#ifdef CONFIG_PRINTK_INDEX +struct pi_entry { + const char *fmt; + const char *func; + const char *file; + unsigned int line; + + /* + * While printk and pr_* have the level stored in the string at compile + * time, some subsystems dynamically add it at runtime through the + * format string. For these dynamic cases, we allow the subsystem to + * tell us the level at compile time. + * + * NULL indicates that the level, if any, is stored in fmt. + */ + const char *level; + + /* + * The format string used by various subsystem specific printk() + * wrappers to prefix the message. + * + * Note that the static prefix defined by the pr_fmt() macro is stored + * directly in the message format (@fmt), not here. + */ + const char *subsys_fmt_prefix; +} __packed; + +#define __printk_index_emit(_fmt, _level, _subsys_fmt_prefix) \ + do { \ + if (__builtin_constant_p(_fmt) && __builtin_constant_p(_level)) { \ + /* + * We check __builtin_constant_p multiple times here + * for the same input because GCC will produce an error + * if we try to assign a static variable to fmt if it + * is not a constant, even with the outer if statement. + */ \ + static const struct pi_entry _entry \ + __used = { \ + .fmt = __builtin_constant_p(_fmt) ? (_fmt) : NULL, \ + .func = __func__, \ + .file = __FILE__, \ + .line = __LINE__, \ + .level = __builtin_constant_p(_level) ? (_level) : NULL, \ + .subsys_fmt_prefix = _subsys_fmt_prefix,\ + }; \ + static const struct pi_entry *_entry_ptr \ + __used __section(".printk_index") = &_entry; \ + } \ + } while (0) + +#else /* !CONFIG_PRINTK_INDEX */ +#define __printk_index_emit(...) do {} while (0) +#endif /* CONFIG_PRINTK_INDEX */ + +/* + * Some subsystems have their own custom printk that applies a va_format to a + * generic format, for example, to include a device number or other metadata + * alongside the format supplied by the caller. + * + * In order to store these in the way they would be emitted by the printk + * infrastructure, the subsystem provides us with the start, fixed string, and + * any subsequent text in the format string. + * + * We take a variable argument list as pr_fmt/dev_fmt/etc are sometimes passed + * as multiple arguments (eg: `"%s: ", "blah"`), and we must only take the + * first one. + * + * subsys_fmt_prefix must be known at compile time, or compilation will fail + * (since this is a mistake). If fmt or level is not known at compile time, no + * index entry will be made (since this can legitimately happen). + */ +#define printk_index_subsys_emit(subsys_fmt_prefix, level, fmt, ...) \ + __printk_index_emit(fmt, level, subsys_fmt_prefix) + +#define printk_index_wrap(_p_func, _fmt, ...) \ + ({ \ + __printk_index_emit(_fmt, NULL, NULL); \ + _p_func(_fmt, ##__VA_ARGS__); \ + }) + + +/** + * printk - print a kernel message + * @fmt: format string + * + * This is printk(). It can be called from any context. We want it to work. + * + * If printk indexing is enabled, _printk() is called from printk_index_wrap. + * Otherwise, printk is simply #defined to _printk. + * + * 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. + */ +#define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__) +#define printk_deferred(fmt, ...) \ + printk_index_wrap(_printk_deferred, fmt, ##__VA_ARGS__) + /** * pr_emerg - Print an emergency-level message * @fmt: format string |