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[lttv.git] / markers-userspace / marker-lib.c

#include "marker.h"
#include <stdio.h>
#include <errno.h>

extern struct marker __start___markers[];
extern struct marker __stop___markers[];

/**
 * __mark_empty_function - Empty probe callback
 * @probe_private: probe private data
 * @call_private: call site private data
 * @fmt: format string
 * @...: variable argument list
 *
 * Empty callback provided as a probe to the markers. By providing this to a
 * disabled marker, we make sure the  execution flow is always valid even
 * though the function pointer change and the marker enabling are two distinct
 * operations that modifies the execution flow of preemptible code.
 */
void __mark_empty_function(void *probe_private, void *call_private,
	const char *fmt, va_list *args)
{
}

/*
 * marker_probe_cb Callback that prepares the variable argument list for probes.
 * @mdata: pointer of type struct marker
 * @call_private: caller site private data
 * @fmt: format string
 * @...:  Variable argument list.
 *
 */
void marker_probe_cb(const struct marker *mdata, void *call_private,
	const char *fmt, ...)
{
	static unsigned int count = 0;

	printf("Test probe function %u\n", count++);
}

__attribute__((constructor)) void marker_init(void)
{
	struct marker *iter;
	int ret;

	printf("Marker section : from %p to %p\n",
		__start___markers, __stop___markers);
	ret = sys_marker(__start___markers, __stop___markers);
	if (ret)
		perror("Error connecting markers");
	for (iter = __start___markers; iter < __stop___markers; iter++) {
		printf("Marker : %s\n", iter->name);
	}
}