perf report: Add GUI report support for s390 auxiliary trace

 * Auxtrace support for s390 CPU-Measurement Sampling Facility

 *

 * Author(s):  Thomas Richter <tmricht@linux.ibm.com>

 *

 * Auxiliary traces are collected during 'perf record' using rbd000 event.

 * Several PERF_RECORD_XXX are generated during recording:

 *

 * PERF_RECORD_AUX:

 *	Records that new data landed in the AUX buffer part.

 * PERF_RECORD_AUXTRACE:

 *	Defines auxtrace data. Followed by the actual data. The contents of

 *	the auxtrace data is dependent on the event and the CPU.

 *	This record is generated by perf record command. For details

 *	see Documentation/perf.data-file-format.txt.

 * PERF_RECORD_AUXTRACE_INFO:

 *	Defines a table of contains for PERF_RECORD_AUXTRACE records. This

 *	record is generated during 'perf record' command. Each record contains up

 *	to 256 entries describing offset and size of the AUXTRACE data in the

 *	perf.data file.

 * PERF_RECORD_AUXTRACE_ERROR:

 *	Indicates an error during AUXTRACE collection such as buffer overflow.

 * PERF_RECORD_FINISHED_ROUND:

 *	Perf events are not necessarily in time stamp order, as they can be

 *	collected in parallel on different CPUs. If the events should be

 *	processed in time order they need to be sorted first.

 *	Perf report guarantees that there is no reordering over a

 *	PERF_RECORD_FINISHED_ROUND boundary event. All perf records with a

 *	time stamp lower than this record are processed (and displayed) before

 *	the succeeding perf record are processed.

 *

 * These records are evaluated during perf report command.

 *

 * 1. PERF_RECORD_AUXTRACE_INFO is used to set up the infrastructure for

 * auxiliary trace data processing. See s390_cpumsf_process_auxtrace_info()

 * below.

 * Auxiliary trace data is collected per CPU. To merge the data into the report

 * an auxtrace_queue is created for each CPU. It is assumed that the auxtrace

 * data is in ascending order.

 *

 * Each queue has a double linked list of auxtrace_buffers. This list contains

 * the offset and size of a CPU's auxtrace data. During auxtrace processing

 * the data portion is mmap()'ed.

 *

 * To sort the queues in chronological order, all queue access is controlled

 * by the auxtrace_heap. This is basicly a stack, each stack element has two

 * entries, the queue number and a time stamp. However the stack is sorted by

 * the time stamps. The highest time stamp is at the bottom the lowest

 * (nearest) time stamp is at the top. That sort order is maintained at all

 * times!

 *

 * After the auxtrace infrastructure has been setup, the auxtrace queues are

 * filled with data (offset/size pairs) and the auxtrace_heap is populated.

 *

 * 2. PERF_RECORD_XXX processing triggers access to the auxtrace_queues.

 * Each record is handled by s390_cpumsf_process_event(). The time stamp of

 * the perf record is compared with the time stamp located on the auxtrace_heap

 * top element. If that time stamp is lower than the time stamp from the

 * record sample, the auxtrace queues will be processed. As auxtrace queues

 * control many auxtrace_buffers and each buffer can be quite large, the

 * auxtrace buffer might be processed only partially. In this case the

 * position in the auxtrace_buffer of that queue is remembered and the time

 * stamp of the last processed entry of the auxtrace_buffer replaces the

 * current auxtrace_heap top.

 *

 * 3. Auxtrace_queues might run of out data and are feeded by the

 * PERF_RECORD_AUXTRACE handling, see s390_cpumsf_process_auxtrace_event().

 *

 * Event Generation

 * Each sampling-data entry in the auxilary trace data generates a perf sample.

 * This sample is filled

 * with data from the auxtrace such as PID/TID, instruction address, CPU state,

 * etc. This sample is processed with perf_session__deliver_synth_event() to

 * be included into the GUI.

 *

 * 4. PERF_RECORD_FINISHED_ROUND event is used to process all the remaining

 * auxiliary traces entries until the time stamp of this record is reached

 * auxtrace_heap top. This is triggered by ordered_event->deliver().

 *

 *

 * Perf event processing.

 * Event processing of PERF_RECORD_XXX entries relies on time stamp entries.

 * This is the function call sequence:

 *

 * __cmd_report()

 * |

 * perf_session__process_events()

 * |

 * __perf_session__process_events()

 * |

 * perf_session__process_event()

 * |  This functions splits the PERF_RECORD_XXX records.

 * |  - Those generated by perf record command (type number equal or higher

 * |    than PERF_RECORD_USER_TYPE_START) are handled by

 * |    perf_session__process_user_event(see below)

 * |  - Those generated by the kernel are handled by

 * |    perf_evlist__parse_sample_timestamp()

 * |

 * perf_evlist__parse_sample_timestamp()

 * |  Extract time stamp from sample data.

 * |

 * perf_session__queue_event()

 * |  If timestamp is positive the sample is entered into an ordered_event

 * |  list, sort order is the timestamp. The event processing is deferred until

 * |  later (see perf_session__process_user_event()).

 * |  Other timestamps (0 or -1) are handled immediately by

 * |  perf_session__deliver_event(). These are events generated at start up

 * |  of command perf record. They create PERF_RECORD_COMM and PERF_RECORD_MMAP*

 * |  records. They are needed to create a list of running processes and its

 * |  memory mappings and layout. They are needed at the beginning to enable

 * |  command perf report to create process trees and memory mappings.

 * |

 * perf_session__deliver_event()

 * |  Delivers a PERF_RECORD_XXX entry for handling.

 * |

 * auxtrace__process_event()

 * |  The timestamp of the PERF_RECORD_XXX entry is taken to correlate with

 * |  time stamps from the auxiliary trace buffers. This enables

 * |  synchronization between auxiliary trace data and the events on the

 * |  perf.data file.

 * |

 * machine__deliver_event()

 * |  Handles the PERF_RECORD_XXX event. This depends on the record type.

 *    It might update the process tree, update a process memory map or enter

 *    a sample with IP and call back chain data into GUI data pool.

 *

 *

 * Deferred processing determined by perf_session__process_user_event() is

 * finally processed when a PERF_RECORD_FINISHED_ROUND is encountered. These

 * are generated during command perf record.

 * The timestamp of PERF_RECORD_FINISHED_ROUND event is taken to process all

 * PERF_RECORD_XXX entries stored in the ordered_event list. This list was

 * built up while reading the perf.data file.

 * Each event is now processed by calling perf_session__deliver_event().

 * This enables time synchronization between the data in the perf.data file and

 * the data in the auxiliary trace buffers.

 */

#include <endian.h>

	u32			auxtrace_type;

	u32			pmu_type;

	u16			machine_type;

	bool			data_queued;

};

struct s390_cpumsf_queue {

	struct s390_cpumsf	*sf;

	unsigned int		queue_nr;

	struct auxtrace_buffer	*buffer;

	int			cpu;

};

/* Display s390 CPU measurement facility basic-sampling data entry */

	const char *color = PERF_COLOR_BLUE;

	struct hws_basic_entry *basic;

	struct hws_diag_entry *diag;

	size_t pos = 0;

	unsigned short bsdes, dsdes;

	size_t pos = 0;

	color_fprintf(stdout, color,

		      ". ... s390 AUX data: size %zu bytes\n",

	s390_cpumsf_dump(sf, buf, len);

}

#define	S390_LPP_PID_MASK	0xffffffff

static bool s390_cpumsf_make_event(size_t pos,

				   struct hws_basic_entry *basic,

				   struct s390_cpumsf_queue *sfq)

{

	struct perf_sample sample = {

				.ip = basic->ia,

				.pid = basic->hpp & S390_LPP_PID_MASK,

				.tid = basic->hpp & S390_LPP_PID_MASK,

				.cpumode = PERF_RECORD_MISC_CPUMODE_UNKNOWN,

				.cpu = sfq->cpu,

				.period = 1

			    };

	union perf_event event;

	memset(&event, 0, sizeof(event));

	if (basic->CL == 1)	/* Native LPAR mode */

		sample.cpumode = basic->P ? PERF_RECORD_MISC_USER

					  : PERF_RECORD_MISC_KERNEL;

	else if (basic->CL == 2)	/* Guest kernel/user space */

		sample.cpumode = basic->P ? PERF_RECORD_MISC_GUEST_USER

					  : PERF_RECORD_MISC_GUEST_KERNEL;

	else if (basic->gpp || basic->prim_asn != 0xffff)

		/* Use heuristics on old hardware */

		sample.cpumode = basic->P ? PERF_RECORD_MISC_GUEST_USER

					  : PERF_RECORD_MISC_GUEST_KERNEL;

	else

		sample.cpumode = basic->P ? PERF_RECORD_MISC_USER

					  : PERF_RECORD_MISC_KERNEL;

	event.sample.header.type = PERF_RECORD_SAMPLE;

	event.sample.header.misc = sample.cpumode;

	event.sample.header.size = sizeof(struct perf_event_header);

	pr_debug4("%s pos:%#zx ip:%#" PRIx64 " P:%d CL:%d pid:%d.%d cpumode:%d cpu:%d\n",

		 __func__, pos, sample.ip, basic->P, basic->CL, sample.pid,

		 sample.tid, sample.cpumode, sample.cpu);

	if (perf_session__deliver_synth_event(sfq->sf->session, &event,

					      &sample)) {

		pr_err("s390 Auxiliary Trace: failed to deliver event\n");

		return false;

	}

	return true;

}

static unsigned long long get_trailer_time(const unsigned char *buf)

{

	struct hws_trailer_entry *te;

	unsigned long long aux_time;

	te = (struct hws_trailer_entry *)(buf + S390_CPUMSF_PAGESZ

					      - sizeof(*te));

	if (!te->clock_base)	/* TOD_CLOCK_BASE value missing */

		return 0;

	/* Correct calculation to convert time stamp in trailer entry to

	 * nano seconds (taken from arch/s390 function tod_to_ns()).

	 * TOD_CLOCK_BASE is stored in trailer entry member progusage2.

	 */

	aux_time = trailer_timestamp(te) - te->progusage2;

	aux_time = (aux_time >> 9) * 125 + (((aux_time & 0x1ff) * 125) >> 9);

	return aux_time;

}

/* Process the data samples of a single queue. The first parameter is a

 * pointer to the queue, the second parameter is the time stamp. This

 * is the time stamp:

 * - of the event that triggered this processing.

 * - or the time stamp when the last proccesing of this queue stopped.

 *   In this case it stopped at a 4KB page boundary and record the

 *   position on where to continue processing on the next invocation

 *   (see buffer->use_data and buffer->use_size).

 *

 * When this function returns the second parameter is updated to

 * reflect the time stamp of the last processed auxiliary data entry

 * (taken from the trailer entry of that page). The caller uses this

 * returned time stamp to record the last processed entry in this

 * queue.

 *

 * The function returns:

 * 0:  Processing successful. The second parameter returns the

 *     time stamp from the trailer entry until which position

 *     processing took place. Subsequent calls resume from this

 *     position.

 * <0: An error occurred during processing. The second parameter

 *     returns the maximum time stamp.

 * >0: Done on this queue. The second parameter returns the

 *     maximum time stamp.

 */

static int s390_cpumsf_samples(struct s390_cpumsf_queue *sfq, u64 *ts)

{

	struct s390_cpumsf *sf = sfq->sf;

	unsigned char *buf = sfq->buffer->use_data;

	size_t len = sfq->buffer->use_size;

	struct hws_basic_entry *basic;

	unsigned short bsdes, dsdes;

	size_t pos = 0;

	int err = 1;

	u64 aux_ts;

	if (!s390_cpumsf_validate(sf->machine_type, buf, len, &bsdes,

				  &dsdes)) {

		*ts = ~0ULL;

		return -1;

	}

	/* Get trailer entry time stamp and check if entries in

	 * this auxiliary page are ready for processing. If the

	 * time stamp of the first entry is too high, whole buffer

	 * can be skipped. In this case return time stamp.

	 */

	aux_ts = get_trailer_time(buf);

	if (!aux_ts) {

		pr_err("[%#08" PRIx64 "] Invalid AUX trailer entry TOD clock base\n",

		       sfq->buffer->data_offset);

		aux_ts = ~0ULL;

		goto out;

	}

	if (aux_ts > *ts) {

		*ts = aux_ts;

		return 0;

	}

	while (pos < len) {

		/* Handle Basic entry */

		basic = (struct hws_basic_entry *)(buf + pos);

		if (s390_cpumsf_make_event(pos, basic, sfq))

			pos += bsdes;

		else {

			err = -EBADF;

			goto out;

		}

		pos += dsdes;	/* Skip diagnositic entry */

		/* Check for trailer entry */

		if (!s390_cpumsf_reached_trailer(bsdes + dsdes, pos)) {

			pos = (pos + S390_CPUMSF_PAGESZ)

			       & ~(S390_CPUMSF_PAGESZ - 1);

			/* Check existence of next page */

			if (pos >= len)

				break;

			aux_ts = get_trailer_time(buf + pos);

			if (!aux_ts) {

				aux_ts = ~0ULL;

				goto out;

			}

			if (aux_ts > *ts) {

				*ts = aux_ts;

				sfq->buffer->use_data += pos;

				sfq->buffer->use_size -= pos;

				return 0;

			}

		}

	}

out:

	*ts = aux_ts;

	sfq->buffer->use_size = 0;

	sfq->buffer->use_data = NULL;

	return err;	/* Buffer completely scanned or error */

}

/* Run the s390 auxiliary trace decoder.

 * Select the queue buffer to operate on, the caller already selected

 * the proper queue, depending on second parameter 'ts'.

 * This is the time stamp until which the auxiliary entries should

 * be processed. This value is updated by called functions and

 * returned to the caller.

 *

 * Resume processing in the current buffer. If there is no buffer

 * get a new buffer from the queue and setup start position for

 * processing.

 * When a buffer is completely processed remove it from the queue

 * before returning.

 *

 * This function returns

 * 1: When the queue is empty. Second parameter will be set to

 *    maximum time stamp.

 * 0: Normal processing done.

 * <0: Error during queue buffer setup. This causes the caller

 *     to stop processing completely.

 */

static int s390_cpumsf_run_decoder(struct s390_cpumsf_queue *sfq,

				   u64 *ts)

{

	struct auxtrace_buffer *buffer;

	struct auxtrace_queue *queue;

	int err;

	queue = &sfq->sf->queues.queue_array[sfq->queue_nr];

	/* Get buffer and last position in buffer to resume

	 * decoding the auxiliary entries. One buffer might be large

	 * and decoding might stop in between. This depends on the time

	 * stamp of the trailer entry in each page of the auxiliary

	 * data and the time stamp of the event triggering the decoding.

	 */

	if (sfq->buffer == NULL) {

		sfq->buffer = buffer = auxtrace_buffer__next(queue,

							     sfq->buffer);

		if (!buffer) {

			*ts = ~0ULL;

			return 1;	/* Processing done on this queue */

		}

		/* Start with a new buffer on this queue */

		if (buffer->data) {

			buffer->use_size = buffer->size;

			buffer->use_data = buffer->data;

		}

	} else

		buffer = sfq->buffer;

	if (!buffer->data) {

		int fd = perf_data__fd(sfq->sf->session->data);

		buffer->data = auxtrace_buffer__get_data(buffer, fd);

		if (!buffer->data)

			return -ENOMEM;

		buffer->use_size = buffer->size;

		buffer->use_data = buffer->data;

	}

	pr_debug4("%s queue_nr:%d buffer:%" PRId64 " offset:%#" PRIx64 " size:%#zx rest:%#zx\n",

		  __func__, sfq->queue_nr, buffer->buffer_nr, buffer->offset,

		  buffer->size, buffer->use_size);

	err = s390_cpumsf_samples(sfq, ts);

	/* If non-zero, there is either an error (err < 0) or the buffer is

	 * completely done (err > 0). The error is unrecoverable, usually

	 * some descriptors could not be read successfully, so continue with

	 * the next buffer.

	 * In both cases the parameter 'ts' has been updated.

	 */

	if (err) {

		sfq->buffer = NULL;

		list_del(&buffer->list);

		auxtrace_buffer__free(buffer);

		if (err > 0)		/* Buffer done, no error */

			err = 0;

	}

	return err;

}

static struct s390_cpumsf_queue *

s390_cpumsf_alloc_queue(struct s390_cpumsf *sf, unsigned int queue_nr)

{

	struct s390_cpumsf_queue *sfq;

	sfq = zalloc(sizeof(struct s390_cpumsf_queue));

	if (sfq == NULL)

		return NULL;

	sfq->sf = sf;

	sfq->queue_nr = queue_nr;

	sfq->cpu = -1;

	return sfq;

}

static int s390_cpumsf_setup_queue(struct s390_cpumsf *sf,

				   struct auxtrace_queue *queue,

				   unsigned int queue_nr, u64 ts)

{

	struct s390_cpumsf_queue *sfq = queue->priv;

	if (list_empty(&queue->head))

		return 0;

	if (sfq == NULL) {

		sfq = s390_cpumsf_alloc_queue(sf, queue_nr);

		if (!sfq)

			return -ENOMEM;

		queue->priv = sfq;

		if (queue->cpu != -1)

			sfq->cpu = queue->cpu;

	}

	return auxtrace_heap__add(&sf->heap, queue_nr, ts);

}

static int s390_cpumsf_setup_queues(struct s390_cpumsf *sf, u64 ts)

{

	unsigned int i;

	int ret = 0;

	for (i = 0; i < sf->queues.nr_queues; i++) {

		ret = s390_cpumsf_setup_queue(sf, &sf->queues.queue_array[i],

					      i, ts);

		if (ret)

			break;

	}

	return ret;

}

static int s390_cpumsf_update_queues(struct s390_cpumsf *sf, u64 ts)

{

	if (!sf->queues.new_data)

		return 0;

	sf->queues.new_data = false;

	return s390_cpumsf_setup_queues(sf, ts);

}

static int s390_cpumsf_process_queues(struct s390_cpumsf *sf, u64 timestamp)

{

	unsigned int queue_nr;

	u64 ts;

	int ret;

	while (1) {

		struct auxtrace_queue *queue;

		struct s390_cpumsf_queue *sfq;

		if (!sf->heap.heap_cnt)

			return 0;

		if (sf->heap.heap_array[0].ordinal >= timestamp)

			return 0;

		queue_nr = sf->heap.heap_array[0].queue_nr;

		queue = &sf->queues.queue_array[queue_nr];

		sfq = queue->priv;

		auxtrace_heap__pop(&sf->heap);

		if (sf->heap.heap_cnt) {

			ts = sf->heap.heap_array[0].ordinal + 1;

			if (ts > timestamp)

				ts = timestamp;

		} else {

			ts = timestamp;

		}

		ret = s390_cpumsf_run_decoder(sfq, &ts);

		if (ret < 0) {

			auxtrace_heap__add(&sf->heap, queue_nr, ts);

			return ret;

		}

		if (!ret) {

			ret = auxtrace_heap__add(&sf->heap, queue_nr, ts);

			if (ret < 0)

				return ret;

		}

	}

	return 0;

}

static int s390_cpumsf_synth_error(struct s390_cpumsf *sf, int code, int cpu,

				   pid_t pid, pid_t tid, u64 ip)

{

	char msg[MAX_AUXTRACE_ERROR_MSG];

	union perf_event event;

	int err;

	strncpy(msg, "Lost Auxiliary Trace Buffer", sizeof(msg) - 1);

	auxtrace_synth_error(&event.auxtrace_error, PERF_AUXTRACE_ERROR_ITRACE,

			     code, cpu, pid, tid, ip, msg);

	err = perf_session__deliver_synth_event(sf->session, &event, NULL);

	if (err)

		pr_err("s390 Auxiliary Trace: failed to deliver error event,"

			"error %d\n", err);

	return err;

}

static int s390_cpumsf_lost(struct s390_cpumsf *sf, struct perf_sample *sample)

{

	return s390_cpumsf_synth_error(sf, 1, sample->cpu,

				       sample->pid, sample->tid, 0);

}

static int

s390_cpumsf_process_event(struct perf_session *session __maybe_unused,

			  union perf_event *event __maybe_unused,

			  struct perf_sample *sample __maybe_unused,

			  struct perf_tool *tool __maybe_unused)

			  union perf_event *event,

			  struct perf_sample *sample,

			  struct perf_tool *tool)

{

	struct s390_cpumsf *sf = container_of(session->auxtrace,

					      struct s390_cpumsf,

					      auxtrace);

	u64 timestamp = sample->time;

	int err = 0;

	if (dump_trace)

		return 0;

	if (!tool->ordered_events) {

		pr_err("s390 Auxiliary Trace requires ordered events\n");

		return -EINVAL;

	}

	if (event->header.type == PERF_RECORD_AUX &&

	    event->aux.flags & PERF_AUX_FLAG_TRUNCATED)

		return s390_cpumsf_lost(sf, sample);

	if (timestamp) {

		err = s390_cpumsf_update_queues(sf, timestamp);

		if (!err)

			err = s390_cpumsf_process_queues(sf, timestamp);

	}

	return err;

}

struct s390_cpumsf_synth {

	struct perf_tool cpumsf_tool;

	struct perf_session *session;

};

static int

s390_cpumsf_process_auxtrace_event(struct perf_session *session,

				   union perf_event *event __maybe_unused,

	off_t data_offset;

	int err;

	if (sf->data_queued)

		return 0;

	if (perf_data__is_pipe(session->data)) {

		data_offset = 0;

	} else {

	return 0;

}

static void s390_cpumsf_free_events(struct perf_session *session __maybe_unused)

{

}

static int s390_cpumsf_flush(struct perf_session *session __maybe_unused,

			     struct perf_tool *tool __maybe_unused)

{

	return 0;

}

static void s390_cpumsf_free_events(struct perf_session *session)

static void s390_cpumsf_free_queues(struct perf_session *session)

{

	struct s390_cpumsf *sf = container_of(session->auxtrace,

					      struct s390_cpumsf,

					      auxtrace);

	auxtrace_heap__free(&sf->heap);

	s390_cpumsf_free_events(session);

	s390_cpumsf_free_queues(session);

	session->auxtrace = NULL;

	free(sf);

}

	return (ret == 1) ? family : 0;

}

/* Check itrace options set on perf report command.

 * Return true, if none are set or all options specified can be

 * handled on s390.

 * Return false otherwise.

 */

static bool check_auxtrace_itrace(struct itrace_synth_opts *itops)

{

	if (!itops || !itops->set)

		return true;

	pr_err("No --itrace options supported\n");

	return false;

}

int s390_cpumsf_process_auxtrace_info(union perf_event *event,

				      struct perf_session *session)

{

	if (sf == NULL)

		return -ENOMEM;

	if (!check_auxtrace_itrace(session->itrace_synth_opts)) {

		err = -EINVAL;

		goto err_free;

	}

	err = auxtrace_queues__init(&sf->queues);

	if (err)

		goto err_free;

	sf->auxtrace.free = s390_cpumsf_free;

	session->auxtrace = &sf->auxtrace;

	if (dump_trace)

		return 0;

	err = auxtrace_queues__process_index(&sf->queues, session);

	if (err)

		goto err_free_queues;

	if (sf->queues.populated)

		sf->data_queued = true;

	return 0;

err_free_queues:

	auxtrace_queues__free(&sf->queues);

	session->auxtrace = NULL;

err_free:

	free(sf);

	return err;