1. 根目录:
2. include
3. linux
4. printk.h

#ifndef __KERNEL_PRINTK__
#define __KERNEL_PRINTK__

#include <linux/init.h>

extern const char linux_banner[];
extern const char linux_proc_banner[];

#define KERN_EMERG	"<0>"	/* system is unusable			*/
#define KERN_ALERT	"<1>"	/* action must be taken immediately	*/
#define KERN_CRIT	"<2>"	/* critical conditions			*/
#define KERN_ERR	"<3>"	/* error conditions			*/
#define KERN_WARNING	"<4>"	/* warning conditions			*/
#define KERN_NOTICE	"<5>"	/* normal but significant condition	*/
#define KERN_INFO	"<6>"	/* informational			*/
#define KERN_DEBUG	"<7>"	/* debug-level messages			*/

/* Use the default kernel loglevel */
#define KERN_DEFAULT	"<d>"
/*
 * Annotation for a "continued" line of log printout (only done after a
 * line that had no enclosing \n). Only to be used by core/arch code
 * during early bootup (a continued line is not SMP-safe otherwise).
 */
#define KERN_CONT	"<c>"

extern int console_printk[];

#define console_loglevel (console_printk[0])
#define default_message_loglevel (console_printk[1])
#define minimum_console_loglevel (console_printk[2])
#define default_console_loglevel (console_printk[3])

static inline void console_silent(void)
{
	console_loglevel = 0;
}

static inline void console_verbose(void)
{
	if (console_loglevel)
		console_loglevel = 15;
}

struct va_format {
	const char *fmt;
	va_list *va;
};

/*
 * FW_BUG
 * Add this to a message where you are sure the firmware is buggy or behaves
 * really stupid or out of spec. Be aware that the responsible BIOS developer
 * should be able to fix this issue or at least get a concrete idea of the
 * problem by reading your message without the need of looking at the kernel
 * code.
 *
 * Use it for definite and high priority BIOS bugs.
 *
 * FW_WARN
 * Use it for not that clear (e.g. could the kernel messed up things already?)
 * and medium priority BIOS bugs.
 *
 * FW_INFO
 * Use this one if you want to tell the user or vendor about something
 * suspicious, but generally harmless related to the firmware.
 *
 * Use it for information or very low priority BIOS bugs.
 */
#define FW_BUG		"[Firmware Bug]: "
#define FW_WARN		"[Firmware Warn]: "
#define FW_INFO		"[Firmware Info]: "

/*
 * HW_ERR
 * Add this to a message for hardware errors, so that user can report
 * it to hardware vendor instead of LKML or software vendor.
 */
#define HW_ERR		"[Hardware Error]: "

/*
 * Dummy printk for disabled debugging statements to use whilst maintaining
 * gcc's format and side-effect checking.
 */
static inline __attribute__ ((format (printf, 1, 2)))
int no_printk(const char *fmt, ...)
{
	return 0;
}

extern asmlinkage __attribute__ ((format (printf, 1, 2)))
void early_printk(const char *fmt, ...);

extern int printk_needs_cpu(int cpu);
extern void printk_tick(void);

#ifdef CONFIG_PRINTK
asmlinkage __attribute__ ((format (printf, 1, 0)))
int vprintk(const char *fmt, va_list args);
asmlinkage __attribute__ ((format (printf, 1, 2))) __cold
int printk(const char *fmt, ...);

/*
 * Please don't use printk_ratelimit(), because it shares ratelimiting state
 * with all other unrelated printk_ratelimit() callsites.  Instead use
 * printk_ratelimited() or plain old __ratelimit().
 */
extern int __printk_ratelimit(const char *func);
#define printk_ratelimit() __printk_ratelimit(__func__)
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
				   unsigned int interval_msec);

extern int printk_delay_msec;
extern int dmesg_restrict;
extern int kptr_restrict;

void log_buf_kexec_setup(void);
void __init setup_log_buf(int early);
#else
static inline __attribute__ ((format (printf, 1, 0)))
int vprintk(const char *s, va_list args)
{
	return 0;
}
static inline __attribute__ ((format (printf, 1, 2))) __cold
int printk(const char *s, ...)
{
	return 0;
}
static inline int printk_ratelimit(void)
{
	return 0;
}
static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies,
					  unsigned int interval_msec)
{
	return false;
}

static inline void log_buf_kexec_setup(void)
{
}

static inline void setup_log_buf(int early)
{
}
#endif

extern void dump_stack(void) __cold;

#ifndef pr_fmt
#define pr_fmt(fmt) fmt
#endif

#define pr_emerg(fmt, ...) \
	printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
#define pr_alert(fmt, ...) \
	printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
#define pr_crit(fmt, ...) \
	printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
#define pr_err(fmt, ...) \
	printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
#define pr_warning(fmt, ...) \
	printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
#define pr_warn pr_warning
#define pr_notice(fmt, ...) \
	printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
#define pr_info(fmt, ...) \
	printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
#define pr_cont(fmt, ...) \
	printk(KERN_CONT fmt, ##__VA_ARGS__)

/* pr_devel() should produce zero code unless DEBUG is defined */
#ifdef DEBUG
#define pr_devel(fmt, ...) \
	printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#else
#define pr_devel(fmt, ...) \
	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#endif

/* If you are writing a driver, please use dev_dbg instead */
#if defined(DEBUG)
#define pr_debug(fmt, ...) \
	printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#elif defined(CONFIG_DYNAMIC_DEBUG)
/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
#define pr_debug(fmt, ...) \
	dynamic_pr_debug(fmt, ##__VA_ARGS__)
#else
#define pr_debug(fmt, ...) \
	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#endif

/*
 * Print a one-time message (analogous to WARN_ONCE() et al):
 */

#ifdef CONFIG_PRINTK
#define printk_once(fmt, ...)			\
({						\
	static bool __print_once;		\
						\
	if (!__print_once) {			\
		__print_once = true;		\
		printk(fmt, ##__VA_ARGS__);	\
	}					\
})
#else
#define printk_once(fmt, ...)			\
	no_printk(fmt, ##__VA_ARGS__)
#endif

#define pr_emerg_once(fmt, ...)					\
	printk_once(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
#define pr_alert_once(fmt, ...)					\
	printk_once(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
#define pr_crit_once(fmt, ...)					\
	printk_once(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
#define pr_err_once(fmt, ...)					\
	printk_once(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
#define pr_warn_once(fmt, ...)					\
	printk_once(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
#define pr_notice_once(fmt, ...)				\
	printk_once(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
#define pr_info_once(fmt, ...)					\
	printk_once(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
#define pr_cont_once(fmt, ...)					\
	printk_once(KERN_CONT pr_fmt(fmt), ##__VA_ARGS__)
/* If you are writing a driver, please use dev_dbg instead */
#if defined(DEBUG)
#define pr_debug_once(fmt, ...)					\
	printk_once(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#else
#define pr_debug_once(fmt, ...)					\
	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#endif

/*
 * ratelimited messages with local ratelimit_state,
 * no local ratelimit_state used in the !PRINTK case
 */
#ifdef CONFIG_PRINTK
#define printk_ratelimited(fmt, ...)					\
({									\
	static DEFINE_RATELIMIT_STATE(_rs,				\
				      DEFAULT_RATELIMIT_INTERVAL,	\
				      DEFAULT_RATELIMIT_BURST);		\
									\
	if (__ratelimit(&_rs))						\
		printk(fmt, ##__VA_ARGS__);				\
})
#else
#define printk_ratelimited(fmt, ...)					\
	no_printk(fmt, ##__VA_ARGS__)
#endif

#define pr_emerg_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
#define pr_alert_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
#define pr_crit_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
#define pr_err_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
#define pr_warn_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
#define pr_notice_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
#define pr_info_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
/* no pr_cont_ratelimited, don't do that... */
/* If you are writing a driver, please use dev_dbg instead */
#if defined(DEBUG)
#define pr_debug_ratelimited(fmt, ...)					\
	printk_ratelimited(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#else
#define pr_debug_ratelimited(fmt, ...) \
	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#endif

enum {
	DUMP_PREFIX_NONE,
	DUMP_PREFIX_ADDRESS,
	DUMP_PREFIX_OFFSET
};
extern void hex_dump_to_buffer(const void *buf, size_t len,
			       int rowsize, int groupsize,
			       char *linebuf, size_t linebuflen, bool ascii);
#ifdef CONFIG_PRINTK
extern void print_hex_dump(const char *level, const char *prefix_str,
			   int prefix_type, int rowsize, int groupsize,
			   const void *buf, size_t len, bool ascii);
extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
				 const void *buf, size_t len);
#else
static inline void print_hex_dump(const char *level, const char *prefix_str,
				  int prefix_type, int rowsize, int groupsize,
				  const void *buf, size_t len, bool ascii)
{
}
static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
					const void *buf, size_t len)
{
}

#endif

#endif