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![Kay Sievers](/assets/img/avatar_default.png)
Support for multiple concurrent readers of /dev/kmsg, with read(), seek(), poll() support. Output of message sequence numbers, to allow userspace log consumers to reliably reconnect and reconstruct their state at any given time. After open("/dev/kmsg"), read() always returns *all* buffered records. If only future messages should be read, SEEK_END can be used. In case records get overwritten while /dev/kmsg is held open, or records get faster overwritten than they are read, the next read() will return -EPIPE and the current reading position gets updated to the next available record. The passed sequence numbers allow the log consumer to calculate the amount of lost messages. [root@mop ~]# cat /dev/kmsg 5,0,0;Linux version 3.4.0-rc1+ (kay@mop) (gcc version 4.7.0 20120315 ... 6,159,423091;ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) 7,160,424069;pci_root PNP0A03:00: host bridge window [io 0x0000-0x0cf7] (ignored) SUBSYSTEM=acpi DEVICE=+acpi:PNP0A03:00 6,339,5140900;NET: Registered protocol family 10 30,340,5690716;udevd[80]: starting version 181 6,341,6081421;FDC 0 is a S82078B 6,345,6154686;microcode: CPU0 sig=0x623, pf=0x0, revision=0x0 7,346,6156968;sr 1:0:0:0: Attached scsi CD-ROM sr0 SUBSYSTEM=scsi DEVICE=+scsi:1:0:0:0 6,347,6289375;microcode: CPU1 sig=0x623, pf=0x0, revision=0x0 Cc: Karel Zak <kzak@redhat.com> Tested-by: William Douglas <william.douglas@intel.com> Signed-off-by: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
332 lines
9.4 KiB
C
332 lines
9.4 KiB
C
#ifndef __KERNEL_PRINTK__
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#define __KERNEL_PRINTK__
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#include <linux/init.h>
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extern const char linux_banner[];
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extern const char linux_proc_banner[];
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#define KERN_EMERG "<0>" /* system is unusable */
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#define KERN_ALERT "<1>" /* action must be taken immediately */
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#define KERN_CRIT "<2>" /* critical conditions */
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#define KERN_ERR "<3>" /* error conditions */
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#define KERN_WARNING "<4>" /* warning conditions */
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#define KERN_NOTICE "<5>" /* normal but significant condition */
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#define KERN_INFO "<6>" /* informational */
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#define KERN_DEBUG "<7>" /* debug-level messages */
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/* Use the default kernel loglevel */
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#define KERN_DEFAULT "<d>"
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/*
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* Annotation for a "continued" line of log printout (only done after a
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* line that had no enclosing \n). Only to be used by core/arch code
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* during early bootup (a continued line is not SMP-safe otherwise).
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*/
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#define KERN_CONT "<c>"
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extern int console_printk[];
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#define console_loglevel (console_printk[0])
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#define default_message_loglevel (console_printk[1])
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#define minimum_console_loglevel (console_printk[2])
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#define default_console_loglevel (console_printk[3])
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static inline void console_silent(void)
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{
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console_loglevel = 0;
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}
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static inline void console_verbose(void)
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{
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if (console_loglevel)
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console_loglevel = 15;
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}
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struct va_format {
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const char *fmt;
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va_list *va;
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};
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/*
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* FW_BUG
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* Add this to a message where you are sure the firmware is buggy or behaves
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* really stupid or out of spec. Be aware that the responsible BIOS developer
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* should be able to fix this issue or at least get a concrete idea of the
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* problem by reading your message without the need of looking at the kernel
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* code.
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*
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* Use it for definite and high priority BIOS bugs.
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*
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* FW_WARN
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* Use it for not that clear (e.g. could the kernel messed up things already?)
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* and medium priority BIOS bugs.
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*
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* FW_INFO
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* Use this one if you want to tell the user or vendor about something
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* suspicious, but generally harmless related to the firmware.
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*
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* Use it for information or very low priority BIOS bugs.
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*/
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#define FW_BUG "[Firmware Bug]: "
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#define FW_WARN "[Firmware Warn]: "
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#define FW_INFO "[Firmware Info]: "
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/*
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* HW_ERR
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* Add this to a message for hardware errors, so that user can report
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* it to hardware vendor instead of LKML or software vendor.
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*/
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#define HW_ERR "[Hardware Error]: "
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/*
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* Dummy printk for disabled debugging statements to use whilst maintaining
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* gcc's format and side-effect checking.
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*/
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static inline __printf(1, 2)
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int no_printk(const char *fmt, ...)
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{
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return 0;
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}
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extern asmlinkage __printf(1, 2)
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void early_printk(const char *fmt, ...);
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extern int printk_needs_cpu(int cpu);
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extern void printk_tick(void);
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#ifdef CONFIG_PRINTK
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asmlinkage __printf(5, 0)
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int vprintk_emit(int facility, int level,
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const char *dict, size_t dictlen,
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const char *fmt, va_list args);
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asmlinkage __printf(1, 0)
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int vprintk(const char *fmt, va_list args);
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asmlinkage __printf(5, 6) __cold
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asmlinkage int printk_emit(int facility, int level,
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const char *dict, size_t dictlen,
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const char *fmt, ...);
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asmlinkage __printf(1, 2) __cold
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int printk(const char *fmt, ...);
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/*
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* Special printk facility for scheduler use only, _DO_NOT_USE_ !
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*/
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__printf(1, 2) __cold int printk_sched(const char *fmt, ...);
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/*
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* Please don't use printk_ratelimit(), because it shares ratelimiting state
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* with all other unrelated printk_ratelimit() callsites. Instead use
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* printk_ratelimited() or plain old __ratelimit().
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*/
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extern int __printk_ratelimit(const char *func);
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#define printk_ratelimit() __printk_ratelimit(__func__)
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extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
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unsigned int interval_msec);
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extern int printk_delay_msec;
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extern int dmesg_restrict;
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extern int kptr_restrict;
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void log_buf_kexec_setup(void);
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void __init setup_log_buf(int early);
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#else
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static inline __printf(1, 0)
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int vprintk(const char *s, va_list args)
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{
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return 0;
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}
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static inline __printf(1, 2) __cold
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int printk(const char *s, ...)
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{
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return 0;
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}
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static inline __printf(1, 2) __cold
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int printk_sched(const char *s, ...)
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{
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return 0;
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}
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static inline int printk_ratelimit(void)
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{
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return 0;
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}
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static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies,
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unsigned int interval_msec)
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{
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return false;
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}
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static inline void log_buf_kexec_setup(void)
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{
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}
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static inline void setup_log_buf(int early)
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{
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}
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#endif
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extern void dump_stack(void) __cold;
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#ifndef pr_fmt
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#define pr_fmt(fmt) fmt
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#endif
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#define pr_emerg(fmt, ...) \
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printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_alert(fmt, ...) \
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printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_crit(fmt, ...) \
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printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_err(fmt, ...) \
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printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_warning(fmt, ...) \
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printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_warn pr_warning
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#define pr_notice(fmt, ...) \
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printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_info(fmt, ...) \
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printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_cont(fmt, ...) \
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printk(KERN_CONT fmt, ##__VA_ARGS__)
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/* pr_devel() should produce zero code unless DEBUG is defined */
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#ifdef DEBUG
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#define pr_devel(fmt, ...) \
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printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#else
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#define pr_devel(fmt, ...) \
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no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#endif
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/* If you are writing a driver, please use dev_dbg instead */
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#if defined(CONFIG_DYNAMIC_DEBUG)
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/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
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#define pr_debug(fmt, ...) \
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dynamic_pr_debug(fmt, ##__VA_ARGS__)
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#elif defined(DEBUG)
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#define pr_debug(fmt, ...) \
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printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#else
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#define pr_debug(fmt, ...) \
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no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#endif
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/*
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* Print a one-time message (analogous to WARN_ONCE() et al):
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*/
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#ifdef CONFIG_PRINTK
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#define printk_once(fmt, ...) \
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({ \
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static bool __print_once; \
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\
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if (!__print_once) { \
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__print_once = true; \
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printk(fmt, ##__VA_ARGS__); \
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} \
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})
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#else
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#define printk_once(fmt, ...) \
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no_printk(fmt, ##__VA_ARGS__)
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#endif
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#define pr_emerg_once(fmt, ...) \
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printk_once(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_alert_once(fmt, ...) \
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printk_once(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_crit_once(fmt, ...) \
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printk_once(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_err_once(fmt, ...) \
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printk_once(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_warn_once(fmt, ...) \
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printk_once(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_notice_once(fmt, ...) \
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printk_once(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_info_once(fmt, ...) \
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printk_once(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_cont_once(fmt, ...) \
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printk_once(KERN_CONT pr_fmt(fmt), ##__VA_ARGS__)
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/* If you are writing a driver, please use dev_dbg instead */
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#if defined(DEBUG)
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#define pr_debug_once(fmt, ...) \
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printk_once(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#else
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#define pr_debug_once(fmt, ...) \
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no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#endif
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/*
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* ratelimited messages with local ratelimit_state,
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* no local ratelimit_state used in the !PRINTK case
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*/
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#ifdef CONFIG_PRINTK
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#define printk_ratelimited(fmt, ...) \
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({ \
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static DEFINE_RATELIMIT_STATE(_rs, \
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DEFAULT_RATELIMIT_INTERVAL, \
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DEFAULT_RATELIMIT_BURST); \
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\
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if (__ratelimit(&_rs)) \
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printk(fmt, ##__VA_ARGS__); \
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})
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#else
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#define printk_ratelimited(fmt, ...) \
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no_printk(fmt, ##__VA_ARGS__)
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#endif
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#define pr_emerg_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_alert_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_crit_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_err_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_warn_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_notice_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
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#define pr_info_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
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/* no pr_cont_ratelimited, don't do that... */
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/* If you are writing a driver, please use dev_dbg instead */
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#if defined(DEBUG)
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#define pr_debug_ratelimited(fmt, ...) \
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printk_ratelimited(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#else
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#define pr_debug_ratelimited(fmt, ...) \
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no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
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#endif
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extern const struct file_operations kmsg_fops;
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enum {
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DUMP_PREFIX_NONE,
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DUMP_PREFIX_ADDRESS,
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DUMP_PREFIX_OFFSET
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};
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extern void hex_dump_to_buffer(const void *buf, size_t len,
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int rowsize, int groupsize,
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char *linebuf, size_t linebuflen, bool ascii);
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#ifdef CONFIG_PRINTK
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extern void print_hex_dump(const char *level, const char *prefix_str,
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int prefix_type, int rowsize, int groupsize,
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const void *buf, size_t len, bool ascii);
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extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
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const void *buf, size_t len);
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#else
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static inline void print_hex_dump(const char *level, const char *prefix_str,
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int prefix_type, int rowsize, int groupsize,
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const void *buf, size_t len, bool ascii)
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{
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}
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static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
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const void *buf, size_t len)
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{
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}
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#endif
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#endif
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