[kernel patch] Experimental systemtap integration of LTTng

This adds the systemtap facility to the kernel (2.6.17.4) with (I used
LTTng kernel patch patch-2.6.17-lttng-0.5.112.tar.bz2).  I'm sure this
would be better as a module or better, have it be included in the
systemtap generated code, but for now, I just added it as a systemtap
facility config option.

Tom

diff -urpN -X dontdiff linux-2.6.17.4-ltt/include/linux/ltt/ltt-facility-id-systemtap.h linux-2.6.17.4-ltt-systemtap/include/linux/ltt/ltt-facility-id-systemtap.h
--- linux-2.6.17.4-ltt/include/linux/ltt/ltt-facility-id-systemtap.h	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.17.4-ltt-systemtap/include/linux/ltt/ltt-facility-id-systemtap.h	2006-10-05 00:46:58.000000000 -0500
@@ -0,0 +1,21 @@
+#ifndef _LTT_FACILITY_ID_SYSTEMTAP_H_
+#define _LTT_FACILITY_ID_SYSTEMTAP_H_
+
+#ifdef CONFIG_LTT
+#include <linux/ltt-facilities.h>
+
+/****  facility handle  ****/
+
+extern ltt_facility_t ltt_facility_systemtap_3D461C68;
+extern ltt_facility_t ltt_facility_systemtap;
+
+
+/****  event index  ****/
+
+enum systemtap_event {
+	event_systemtap_probelog,
+	facility_systemtap_num_events
+};
+
+#endif //CONFIG_LTT
+#endif //_LTT_FACILITY_ID_SYSTEMTAP_H_
diff -urpN -X dontdiff linux-2.6.17.4-ltt/include/linux/ltt/ltt-facility-systemtap.h linux-2.6.17.4-ltt-systemtap/include/linux/ltt/ltt-facility-systemtap.h
--- linux-2.6.17.4-ltt/include/linux/ltt/ltt-facility-systemtap.h	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.17.4-ltt-systemtap/include/linux/ltt/ltt-facility-systemtap.h	2006-10-05 00:46:37.000000000 -0500
@@ -0,0 +1,179 @@
+#ifndef _LTT_FACILITY_SYSTEMTAP_H_
+#define _LTT_FACILITY_SYSTEMTAP_H_
+
+#include <linux/types.h>
+#include <linux/ltt/ltt-facility-id-systemtap.h>
+#include <linux/ltt-core.h>
+
+/* Named types */
+
+/* Event probelog structures */
+typedef struct lttng_sequence_systemtap_probelog_probedata lttng_sequence_systemtap_probelog_probedata;
+struct lttng_sequence_systemtap_probelog_probedata {
+	unsigned int len;
+	const unsigned char *array;
+};
+
+static inline size_t lttng_get_alignment_sequence_systemtap_probelog_probedata(
+		lttng_sequence_systemtap_probelog_probedata *obj)
+{
+	size_t align=0, localign;
+	localign = sizeof(unsigned int);
+	align = max(align, localign);
+
+	localign = sizeof(unsigned char);
+	align = max(align, localign);
+
+	return align;
+}
+
+static inline void lttng_write_sequence_systemtap_probelog_probedata(
+		char *buffer,
+		size_t *to_base,
+		size_t *to,
+		const char **from,
+		size_t *len,
+		lttng_sequence_systemtap_probelog_probedata *obj)
+{
+	size_t align;
+
+	/* Flush pending memcpy */
+	if(*len != 0) {
+		if(buffer != NULL)
+			memcpy(buffer+*to_base+*to, *from, *len);
+	}
+	*to += *len;
+	*len = 0;
+
+	align = lttng_get_alignment_sequence_systemtap_probelog_probedata(obj);
+
+	if(*len == 0) {
+		*to += ltt_align(*to, align); /* align output */
+	} else {
+		*len += ltt_align(*to+*len, align); /* alignment, ok to do a memcpy of it */
+	}
+
+	/* Contains variable sized fields : must explode the structure */
+
+	/* Copy members */
+	align = sizeof(unsigned int);
+
+	if(*len == 0) {
+		*to += ltt_align(*to, align); /* align output */
+	} else {
+		*len += ltt_align(*to+*len, align); /* alignment, ok to do a memcpy of it */
+	}
+
+	*len += sizeof(unsigned int);
+
+	if(buffer != NULL)
+		memcpy(buffer+*to_base+*to, &obj->len, *len);
+	*to += *len;
+	*len = 0;
+
+	align = sizeof(unsigned char);
+
+	if(*len == 0) {
+		*to += ltt_align(*to, align); /* align output */
+	} else {
+		*len += ltt_align(*to+*len, align); /* alignment, ok to do a memcpy of it */
+	}
+
+	*len += sizeof(unsigned char);
+
+	*len = obj->len * (*len);
+	if(buffer != NULL)
+		memcpy(buffer+*to_base+*to, obj->array, *len);
+	*to += *len;
+	*len = 0;
+
+
+	/* Realign the *to_base on arch size, set *to to 0 */
+	*to += ltt_align(*to, sizeof(void *));
+	*to_base = *to_base+*to;
+	*to = 0;
+
+	/* Put source *from just after the C sequence */
+	*from = (const char*)(obj+1);
+}
+
+
+/* Event probelog logging function */
+static inline void trace_systemtap_probelog(
+		lttng_sequence_systemtap_probelog_probedata * lttng_param_probedata)
+#if (!defined(CONFIG_LTT) || !defined(CONFIG_LTT_FACILITY_SYSTEMTAP))
+{
+}
+#else
+{
+	unsigned int index;
+	struct ltt_channel_struct *channel;
+	struct ltt_trace_struct *trace;
+	void *transport_data;
+	char *buffer = NULL;
+	size_t real_to_base = 0; /* The buffer is allocated on arch_size alignment */
+	size_t *to_base = &real_to_base;
+	size_t real_to = 0;
+	size_t *to = &real_to;
+	size_t real_len = 0;
+	size_t *len = &real_len;
+	size_t reserve_size;
+	size_t slot_size;
+	const char *real_from;
+	const char **from = &real_from;
+	u64 tsc;
+	size_t before_hdr_pad, after_hdr_pad, header_size;
+
+	if(ltt_traces.num_active_traces == 0) return;
+
+	/* For each field, calculate the field size. */
+	/* size = *to_base + *to + *len */
+	/* Assume that the padding for alignment starts at a
+	 * sizeof(void *) address. */
+
+	*from = (const char*)lttng_param_probedata;
+	lttng_write_sequence_systemtap_probelog_probedata(buffer, to_base, to, from, len, lttng_param_probedata);
+	reserve_size = *to_base + *to + *len;
+	preempt_disable();
+	ltt_nesting[smp_processor_id()]++;
+	index = ltt_get_index_from_facility(ltt_facility_systemtap_3D461C68,
+						event_systemtap_probelog);
+
+	list_for_each_entry_rcu(trace, &ltt_traces.head, list) {
+		if(!trace->active) continue;
+
+		channel = ltt_get_channel_from_index(trace, index);
+
+		slot_size = 0;
+		buffer = ltt_reserve_slot(trace, channel, &transport_data,
+			reserve_size, &slot_size, &tsc,
+			&before_hdr_pad, &after_hdr_pad, &header_size);
+		if(!buffer) continue; /* buffer full */
+
+		*to_base = *to = *len = 0;
+
+		ltt_write_event_header(trace, channel, buffer,
+			ltt_facility_systemtap_3D461C68, event_systemtap_probelog,
+			reserve_size, before_hdr_pad, tsc);
+		*to_base += before_hdr_pad + after_hdr_pad + header_size;
+
+		*from = (const char*)lttng_param_probedata;
+		lttng_write_sequence_systemtap_probelog_probedata(buffer, to_base, to, from, len, lttng_param_probedata);
+		/* Flush pending memcpy */
+		if(*len != 0) {
+			memcpy(buffer+*to_base+*to, *from, *len);
+			*to += *len;
+			*len = 0;
+		}
+
+		ltt_commit_slot(channel, &transport_data, buffer, slot_size);
+
+	}
+
+	ltt_nesting[smp_processor_id()]--;
+	preempt_enable_no_resched();
+}
+#endif //(!defined(CONFIG_LTT) || !defined(CONFIG_LTT_FACILITY_SYSTEMTAP))
+
+
+#endif //_LTT_FACILITY_SYSTEMTAP_H_
diff -urpN -X dontdiff linux-2.6.17.4-ltt/ltt/Kconfig linux-2.6.17.4-ltt-systemtap/ltt/Kconfig
--- linux-2.6.17.4-ltt/ltt/Kconfig	2006-09-23 11:41:07.000000000 -0500
+++ linux-2.6.17.4-ltt-systemtap/ltt/Kconfig	2006-10-05 00:47:32.000000000 -0500
@@ -236,6 +236,13 @@ config LTT_FACILITY_STATEDUMP
 	  LTT Kernel State Dump facility. Contains events for dumping kernel
 	  state at the beginning of a trace.
 
+config LTT_FACILITY_SYSTEMTAP
+	bool "Linux Trace Toolkit Systemtap Trace Facility"
+	depends on LTT
+	default y
+	help
+	  LTT Systemtap Trace facility.  Allows Systemtap to use LTT for tracing.
+
 config LTT_FACILITY_TIMER
 	bool "Linux Trace Toolkit Timer Facility"
 	depends on LTT
diff -urpN -X dontdiff linux-2.6.17.4-ltt/ltt/Makefile linux-2.6.17.4-ltt-systemtap/ltt/Makefile
--- linux-2.6.17.4-ltt/ltt/Makefile	2006-09-23 11:41:07.000000000 -0500
+++ linux-2.6.17.4-ltt-systemtap/ltt/Makefile	2006-10-05 00:47:41.000000000 -0500
@@ -19,6 +19,7 @@ obj-$(CONFIG_LTT_FACILITY_STACK)	+= \
 			ltt-facility-loader-stack.o
 obj-$(CONFIG_LTT_FACILITY_STATEDUMP)	+= \
 			ltt-facility-loader-network_ip_interface.o
+obj-$(CONFIG_LTT_FACILITY_SYSTEMTAP)	+= ltt-facility-loader-systemtap.o
 
 obj-$(CONFIG_LTT_TRACER)		+= ltt-core.o
 obj-$(CONFIG_LTT_RELAY)			+= ltt-relay.o
diff -urpN -X dontdiff linux-2.6.17.4-ltt/ltt/ltt-facility-loader-systemtap.c linux-2.6.17.4-ltt-systemtap/ltt/ltt-facility-loader-systemtap.c
--- linux-2.6.17.4-ltt/ltt/ltt-facility-loader-systemtap.c	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.17.4-ltt-systemtap/ltt/ltt-facility-loader-systemtap.c	2006-10-05 00:48:03.000000000 -0500
@@ -0,0 +1,66 @@
+/*
+ * ltt-facility-loader-systemtap.c
+ *
+ * (C) Copyright  2005 - 
+ *          Mathieu Desnoyers ([email protected])
+ *
+ * Contains the LTT facility loader.
+ *
+ */
+
+
+#include <linux/ltt-facilities.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/config.h>
+#include "ltt-facility-loader-systemtap.h"
+
+
+#ifdef CONFIG_LTT
+
+EXPORT_SYMBOL(LTT_FACILITY_SYMBOL);
+EXPORT_SYMBOL(LTT_FACILITY_CHECKSUM_SYMBOL);
+
+static const char ltt_facility_name[] = LTT_FACILITY_NAME;
+
+#define SYMBOL_STRING(sym) #sym
+
+static struct ltt_facility facility = {
+	.name = ltt_facility_name,
+	.num_events = LTT_FACILITY_NUM_EVENTS,
+	.checksum = LTT_FACILITY_CHECKSUM,
+	.symbol = SYMBOL_STRING(LTT_FACILITY_SYMBOL),
+};
+
+static int __init facility_init(void)
+{
+	printk(KERN_INFO "LTT : ltt-facility-systemtap init in kernel\n");
+
+	LTT_FACILITY_SYMBOL = ltt_facility_kernel_register(&facility);
+	LTT_FACILITY_CHECKSUM_SYMBOL = LTT_FACILITY_SYMBOL;
+	
+	return LTT_FACILITY_SYMBOL;
+}
+
+#ifndef MODULE
+__initcall(facility_init);
+#else
+module_init(facility_init);
+static void __exit facility_exit(void)
+{
+	int err;
+
+	err = ltt_facility_unregister(LTT_FACILITY_SYMBOL);
+	if(err != 0)
+		printk(KERN_ERR "LTT : Error in unregistering facility.\n");
+
+}
+module_exit(facility_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Linux Trace Toolkit Facility");
+
+#endif //MODULE
+
+#endif //CONFIG_LTT
diff -urpN -X dontdiff linux-2.6.17.4-ltt/ltt/ltt-facility-loader-systemtap.h linux-2.6.17.4-ltt-systemtap/ltt/ltt-facility-loader-systemtap.h
--- linux-2.6.17.4-ltt/ltt/ltt-facility-loader-systemtap.h	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.17.4-ltt-systemtap/ltt/ltt-facility-loader-systemtap.h	2006-10-05 00:48:05.000000000 -0500
@@ -0,0 +1,20 @@
+#ifndef _LTT_FACILITY_LOADER_SYSTEMTAP_H_
+#define _LTT_FACILITY_LOADER_SYSTEMTAP_H_
+
+#ifdef CONFIG_LTT
+
+#include <linux/ltt-facilities.h>
+#include <linux/ltt/ltt-facility-id-systemtap.h>
+
+ltt_facility_t	ltt_facility_systemtap;
+ltt_facility_t	ltt_facility_systemtap_3D461C68;
+
+#define LTT_FACILITY_SYMBOL		ltt_facility_systemtap
+#define LTT_FACILITY_CHECKSUM_SYMBOL	ltt_facility_systemtap_3D461C68
+#define LTT_FACILITY_CHECKSUM		0x3D461C68
+#define LTT_FACILITY_NAME		"systemtap"
+#define LTT_FACILITY_NUM_EVENTS	facility_systemtap_num_events
+
+#endif //CONFIG_LTT
+
+#endif //_LTT_FACILITY_LOADER_SYSTEMTAP_H_
Files linux-2.6.17.4-ltt/ltt/ltt-statedump.ko and linux-2.6.17.4-ltt-systemtap/ltt/ltt-statedump.ko differ