logging.h File Reference

This is the general kernel logging module. More...

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <inttypes.h>
#include <stdio.h>
#include <time/timer.h>

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Data Structures
struct	log_context_t

Macros
#define	LOGGING_BUFSIZE   4096
	Size of the kernel log ring buffer. Must be a power of two.
#define	__LOG_TIMESTAMP_FORMAT   "[%3" PRIu64 ".%03" PRIu64 "%03" PRIu64 "] "
#define	__LOG_STREAM(time_us, ctx, level, format, ...)
	Writes one log line to the structured logger.
#define	__LOG(_level, prefix, format, ...)
	Writes one log line, using the same timestamp for the whole message.

Functions
void	logging_stream_output (char c, void *arg)
void	logging_buffer_read (char *buf, size_t size, uint64_t offset)

Variables
bool	kernel_boot_complete

Detailed Description

This is the general kernel logging module.

In release mode, the logging levels available are:

• INFO
• WARN

In debug mode, the following additional logging levels are available:

• DEBUG: enabled by default but can be disabled with ENABLE_KERNEL_DEBUG set to 0.

Each kernel module should ideally have its own logging header that depends on this one. The main use case is to have more configurable loggers that can be enabled/disabled depending on the needs.

Macro Definition Documentation

__LOG_TIMESTAMP_FORMAT

#define __LOG_TIMESTAMP_FORMAT   "[%3" PRIu64 ".%03" PRIu64 "%03" PRIu64 "] "

Timestamp prefix ([seconds.microseconds]) for the logger. The seconds are right-aligned on 3 characters and the fractional part is zero-padded to 6 digits.

Function Documentation

logging_buffer_read()

void logging_buffer_read	(	char *	buf,
		size_t	size,
		uint64_t	offset )

Reads from the kernel log ring buffer.

Parameters

buf	destination buffer.
size	buffer size in bytes.
offset	byte offset into the available log data.

logging_stream_output()

void logging_stream_output	(	char	c,
		void *	arg )

This function is used to output logs.

Parameters

c	a character to print
arg	optional argument, either a log_context_t or NULL.

Variable Documentation

kernel_boot_complete

bool kernel_boot_complete

extern

Whether the kernel has finished booting. Until then, logs are written to both the serial port and the screen.