s390/perf: add callback to perf to enable using AUX buffer

libperf-$(CONFIG_DWARF) += dwarf-regs.o

libperf-y += machine.o

libperf-$(CONFIG_AUXTRACE) += auxtrace.o

#include <stdbool.h>

#include <linux/kernel.h>

#include <linux/types.h>

#include <linux/bitops.h>

#include <linux/log2.h>

#include "../../util/evlist.h"

#include "../../util/auxtrace.h"

#include "../../util/evsel.h"

#define PERF_EVENT_CPUM_SF		0xB0000 /* Event: Basic-sampling */

#define PERF_EVENT_CPUM_SF_DIAG		0xBD000 /* Event: Combined-sampling */

#define DEFAULT_AUX_PAGES		128

#define DEFAULT_FREQ			4000

static void cpumsf_free(struct auxtrace_record *itr)

{

	free(itr);

}

static size_t cpumsf_info_priv_size(struct auxtrace_record *itr __maybe_unused,

				    struct perf_evlist *evlist __maybe_unused)

{

	return 0;

}

static int

cpumsf_info_fill(struct auxtrace_record *itr __maybe_unused,

		 struct perf_session *session __maybe_unused,

		 struct auxtrace_info_event *auxtrace_info __maybe_unused,

		 size_t priv_size __maybe_unused)

{

	return 0;

}

static unsigned long

cpumsf_reference(struct auxtrace_record *itr __maybe_unused)

{

	return 0;

}

static int

cpumsf_recording_options(struct auxtrace_record *ar __maybe_unused,

			 struct perf_evlist *evlist __maybe_unused,

			 struct record_opts *opts)

{

	unsigned int factor = 1;

	unsigned int pages;

	opts->full_auxtrace = true;

	/*

	 * The AUX buffer size should be set properly to avoid

	 * overflow of samples if it is not set explicitly.

	 * DEFAULT_AUX_PAGES is an proper size when sampling frequency

	 * is DEFAULT_FREQ. It is expected to hold about 1/2 second

	 * of sampling data. The size used for AUX buffer will scale

	 * according to the specified frequency and DEFAULT_FREQ.

	 */

	if (!opts->auxtrace_mmap_pages) {

		if (opts->user_freq != UINT_MAX)

			factor = (opts->user_freq + DEFAULT_FREQ

				  - 1) / DEFAULT_FREQ;

		pages = DEFAULT_AUX_PAGES * factor;

		opts->auxtrace_mmap_pages = roundup_pow_of_two(pages);

	}

	return 0;

}

static int

cpumsf_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,

			      struct record_opts *opts __maybe_unused,

			      const char *str __maybe_unused)

{

	return 0;

}

/*

 * auxtrace_record__init is called when perf record

 * check if the event really need auxtrace

 */

struct auxtrace_record *auxtrace_record__init(struct perf_evlist *evlist,

					      int *err)

{

	struct auxtrace_record *aux;

	struct perf_evsel *pos;

	int diagnose = 0;

	if (evlist->nr_entries == 0)

		return NULL;

	evlist__for_each_entry(evlist, pos) {

		if (pos->attr.config == PERF_EVENT_CPUM_SF_DIAG) {

			diagnose = 1;

			break;

		}

	}

	if (!diagnose)

		return NULL;

	/* sampling in diagnose mode. alloc aux buffer */

	aux = zalloc(sizeof(*aux));

	if (aux == NULL) {

		*err = -ENOMEM;

		return NULL;

	}

	aux->parse_snapshot_options = cpumsf_parse_snapshot_options;

	aux->recording_options = cpumsf_recording_options;

	aux->info_priv_size = cpumsf_info_priv_size;

	aux->info_fill = cpumsf_info_fill;

	aux->free = cpumsf_free;

	aux->reference = cpumsf_reference;

	return aux;

}