Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3946 insertions, 0 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
new file mode 100644
index 000000000..3c0d74fc1
--- /dev/null
+++ b/tools/perf/util/header.c
@@ -0,0 +1,3946 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <inttypes.h>
+#include "util.h"
+#include "string2.h"
+#include <sys/param.h>
+#include <sys/types.h>
+#include <byteswap.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/stringify.h>
+#include <sys/stat.h>
+#include <sys/utsname.h>
+#include <linux/time64.h>
+#include <dirent.h>
+
+#include "evlist.h"
+#include "evsel.h"
+#include "header.h"
+#include "memswap.h"
+#include "../perf.h"
+#include "trace-event.h"
+#include "session.h"
+#include "symbol.h"
+#include "debug.h"
+#include "cpumap.h"
+#include "pmu.h"
+#include "vdso.h"
+#include "strbuf.h"
+#include "build-id.h"
+#include "data.h"
+#include <api/fs/fs.h>
+#include "asm/bug.h"
+#include "tool.h"
+#include "time-utils.h"
+#include "units.h"
+
+#include "sane_ctype.h"
+
+/*
+ * magic2 = "PERFILE2"
+ * must be a numerical value to let the endianness
+ * determine the memory layout. That way we are able
+ * to detect endianness when reading the perf.data file
+ * back.
+ *
+ * we check for legacy (PERFFILE) format.
+ */
+static const char *__perf_magic1 = "PERFFILE";
+static const u64 __perf_magic2    = 0x32454c4946524550ULL;
+static const u64 __perf_magic2_sw = 0x50455246494c4532ULL;
+
+#define PERF_MAGIC	__perf_magic2
+
+const char perf_version_string[] = PERF_VERSION;
+
+struct perf_file_attr {
+	struct perf_event_attr	attr;
+	struct perf_file_section	ids;
+};
+
+struct feat_fd {
+	struct perf_header	*ph;
+	int			fd;
+	void			*buf;	/* Either buf != NULL or fd >= 0 */
+	ssize_t			offset;
+	size_t			size;
+	struct perf_evsel	*events;
+};
+
+void perf_header__set_feat(struct perf_header *header, int feat)
+{
+	set_bit(feat, header->adds_features);
+}
+
+void perf_header__clear_feat(struct perf_header *header, int feat)
+{
+	clear_bit(feat, header->adds_features);
+}
+
+bool perf_header__has_feat(const struct perf_header *header, int feat)
+{
+	return test_bit(feat, header->adds_features);
+}
+
+static int __do_write_fd(struct feat_fd *ff, const void *buf, size_t size)
+{
+	ssize_t ret = writen(ff->fd, buf, size);
+
+	if (ret != (ssize_t)size)
+		return ret < 0 ? (int)ret : -1;
+	return 0;
+}
+
+static int __do_write_buf(struct feat_fd *ff,  const void *buf, size_t size)
+{
+	/* struct perf_event_header::size is u16 */
+	const size_t max_size = 0xffff - sizeof(struct perf_event_header);
+	size_t new_size = ff->size;
+	void *addr;
+
+	if (size + ff->offset > max_size)
+		return -E2BIG;
+
+	while (size > (new_size - ff->offset))
+		new_size <<= 1;
+	new_size = min(max_size, new_size);
+
+	if (ff->size < new_size) {
+		addr = realloc(ff->buf, new_size);
+		if (!addr)
+			return -ENOMEM;
+		ff->buf = addr;
+		ff->size = new_size;
+	}
+
+	memcpy(ff->buf + ff->offset, buf, size);
+	ff->offset += size;
+
+	return 0;
+}
+
+/* Return: 0 if succeded, -ERR if failed. */
+int do_write(struct feat_fd *ff, const void *buf, size_t size)
+{
+	if (!ff->buf)
+		return __do_write_fd(ff, buf, size);
+	return __do_write_buf(ff, buf, size);
+}
+
+/* Return: 0 if succeded, -ERR if failed. */
+static int do_write_bitmap(struct feat_fd *ff, unsigned long *set, u64 size)
+{
+	u64 *p = (u64 *) set;
+	int i, ret;
+
+	ret = do_write(ff, &size, sizeof(size));
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; (u64) i < BITS_TO_U64(size); i++) {
+		ret = do_write(ff, p + i, sizeof(*p));
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* Return: 0 if succeded, -ERR if failed. */
+int write_padded(struct feat_fd *ff, const void *bf,
+		 size_t count, size_t count_aligned)
+{
+	static const char zero_buf[NAME_ALIGN];
+	int err = do_write(ff, bf, count);
+
+	if (!err)
+		err = do_write(ff, zero_buf, count_aligned - count);
+
+	return err;
+}
+
+#define string_size(str)						\
+	(PERF_ALIGN((strlen(str) + 1), NAME_ALIGN) + sizeof(u32))
+
+/* Return: 0 if succeded, -ERR if failed. */
+static int do_write_string(struct feat_fd *ff, const char *str)
+{
+	u32 len, olen;
+	int ret;
+
+	olen = strlen(str) + 1;
+	len = PERF_ALIGN(olen, NAME_ALIGN);
+
+	/* write len, incl. \0 */
+	ret = do_write(ff, &len, sizeof(len));
+	if (ret < 0)
+		return ret;
+
+	return write_padded(ff, str, olen, len);
+}
+
+static int __do_read_fd(struct feat_fd *ff, void *addr, ssize_t size)
+{
+	ssize_t ret = readn(ff->fd, addr, size);
+
+	if (ret != size)
+		return ret < 0 ? (int)ret : -1;
+	return 0;
+}
+
+static int __do_read_buf(struct feat_fd *ff, void *addr, ssize_t size)
+{
+	if (size > (ssize_t)ff->size - ff->offset)
+		return -1;
+
+	memcpy(addr, ff->buf + ff->offset, size);
+	ff->offset += size;
+
+	return 0;
+
+}
+
+static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+{
+	if (!ff->buf)
+		return __do_read_fd(ff, addr, size);
+	return __do_read_buf(ff, addr, size);
+}
+
+static int do_read_u32(struct feat_fd *ff, u32 *addr)
+{
+	int ret;
+
+	ret = __do_read(ff, addr, sizeof(*addr));
+	if (ret)
+		return ret;
+
+	if (ff->ph->needs_swap)
+		*addr = bswap_32(*addr);
+	return 0;
+}
+
+static int do_read_u64(struct feat_fd *ff, u64 *addr)
+{
+	int ret;
+
+	ret = __do_read(ff, addr, sizeof(*addr));
+	if (ret)
+		return ret;
+
+	if (ff->ph->needs_swap)
+		*addr = bswap_64(*addr);
+	return 0;
+}
+
+static char *do_read_string(struct feat_fd *ff)
+{
+	u32 len;
+	char *buf;
+
+	if (do_read_u32(ff, &len))
+		return NULL;
+
+	buf = malloc(len);
+	if (!buf)
+		return NULL;
+
+	if (!__do_read(ff, buf, len)) {
+		/*
+		 * strings are padded by zeroes
+		 * thus the actual strlen of buf
+		 * may be less than len
+		 */
+		return buf;
+	}
+
+	free(buf);
+	return NULL;
+}
+
+/* Return: 0 if succeded, -ERR if failed. */
+static int do_read_bitmap(struct feat_fd *ff, unsigned long **pset, u64 *psize)
+{
+	unsigned long *set;
+	u64 size, *p;
+	int i, ret;
+
+	ret = do_read_u64(ff, &size);
+	if (ret)
+		return ret;
+
+	set = bitmap_alloc(size);
+	if (!set)
+		return -ENOMEM;
+
+	p = (u64 *) set;
+
+	for (i = 0; (u64) i < BITS_TO_U64(size); i++) {
+		ret = do_read_u64(ff, p + i);
+		if (ret < 0) {
+			free(set);
+			return ret;
+		}
+	}
+
+	*pset  = set;
+	*psize = size;
+	return 0;
+}
+
+static int write_tracing_data(struct feat_fd *ff,
+			      struct perf_evlist *evlist)
+{
+	if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+		return -1;
+
+	return read_tracing_data(ff->fd, &evlist->entries);
+}
+
+static int write_build_id(struct feat_fd *ff,
+			  struct perf_evlist *evlist __maybe_unused)
+{
+	struct perf_session *session;
+	int err;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	if (!perf_session__read_build_ids(session, true))
+		return -1;
+
+	if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+		return -1;
+
+	err = perf_session__write_buildid_table(session, ff);
+	if (err < 0) {
+		pr_debug("failed to write buildid table\n");
+		return err;
+	}
+	perf_session__cache_build_ids(session);
+
+	return 0;
+}
+
+static int write_hostname(struct feat_fd *ff,
+			  struct perf_evlist *evlist __maybe_unused)
+{
+	struct utsname uts;
+	int ret;
+
+	ret = uname(&uts);
+	if (ret < 0)
+		return -1;
+
+	return do_write_string(ff, uts.nodename);
+}
+
+static int write_osrelease(struct feat_fd *ff,
+			   struct perf_evlist *evlist __maybe_unused)
+{
+	struct utsname uts;
+	int ret;
+
+	ret = uname(&uts);
+	if (ret < 0)
+		return -1;
+
+	return do_write_string(ff, uts.release);
+}
+
+static int write_arch(struct feat_fd *ff,
+		      struct perf_evlist *evlist __maybe_unused)
+{
+	struct utsname uts;
+	int ret;
+
+	ret = uname(&uts);
+	if (ret < 0)
+		return -1;
+
+	return do_write_string(ff, uts.machine);
+}
+
+static int write_version(struct feat_fd *ff,
+			 struct perf_evlist *evlist __maybe_unused)
+{
+	return do_write_string(ff, perf_version_string);
+}
+
+static int __write_cpudesc(struct feat_fd *ff, const char *cpuinfo_proc)
+{
+	FILE *file;
+	char *buf = NULL;
+	char *s, *p;
+	const char *search = cpuinfo_proc;
+	size_t len = 0;
+	int ret = -1;
+
+	if (!search)
+		return -1;
+
+	file = fopen("/proc/cpuinfo", "r");
+	if (!file)
+		return -1;
+
+	while (getline(&buf, &len, file) > 0) {
+		ret = strncmp(buf, search, strlen(search));
+		if (!ret)
+			break;
+	}
+
+	if (ret) {
+		ret = -1;
+		goto done;
+	}
+
+	s = buf;
+
+	p = strchr(buf, ':');
+	if (p && *(p+1) == ' ' && *(p+2))
+		s = p + 2;
+	p = strchr(s, '\n');
+	if (p)
+		*p = '\0';
+
+	/* squash extra space characters (branding string) */
+	p = s;
+	while (*p) {
+		if (isspace(*p)) {
+			char *r = p + 1;
+			char *q = r;
+			*p = ' ';
+			while (*q && isspace(*q))
+				q++;
+			if (q != (p+1))
+				while ((*r++ = *q++));
+		}
+		p++;
+	}
+	ret = do_write_string(ff, s);
+done:
+	free(buf);
+	fclose(file);
+	return ret;
+}
+
+static int write_cpudesc(struct feat_fd *ff,
+		       struct perf_evlist *evlist __maybe_unused)
+{
+	const char *cpuinfo_procs[] = CPUINFO_PROC;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(cpuinfo_procs); i++) {
+		int ret;
+		ret = __write_cpudesc(ff, cpuinfo_procs[i]);
+		if (ret >= 0)
+			return ret;
+	}
+	return -1;
+}
+
+
+static int write_nrcpus(struct feat_fd *ff,
+			struct perf_evlist *evlist __maybe_unused)
+{
+	long nr;
+	u32 nrc, nra;
+	int ret;
+
+	nrc = cpu__max_present_cpu();
+
+	nr = sysconf(_SC_NPROCESSORS_ONLN);
+	if (nr < 0)
+		return -1;
+
+	nra = (u32)(nr & UINT_MAX);
+
+	ret = do_write(ff, &nrc, sizeof(nrc));
+	if (ret < 0)
+		return ret;
+
+	return do_write(ff, &nra, sizeof(nra));
+}
+
+static int write_event_desc(struct feat_fd *ff,
+			    struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+	u32 nre, nri, sz;
+	int ret;
+
+	nre = evlist->nr_entries;
+
+	/*
+	 * write number of events
+	 */
+	ret = do_write(ff, &nre, sizeof(nre));
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * size of perf_event_attr struct
+	 */
+	sz = (u32)sizeof(evsel->attr);
+	ret = do_write(ff, &sz, sizeof(sz));
+	if (ret < 0)
+		return ret;
+
+	evlist__for_each_entry(evlist, evsel) {
+		ret = do_write(ff, &evsel->attr, sz);
+		if (ret < 0)
+			return ret;
+		/*
+		 * write number of unique id per event
+		 * there is one id per instance of an event
+		 *
+		 * copy into an nri to be independent of the
+		 * type of ids,
+		 */
+		nri = evsel->ids;
+		ret = do_write(ff, &nri, sizeof(nri));
+		if (ret < 0)
+			return ret;
+
+		/*
+		 * write event string as passed on cmdline
+		 */
+		ret = do_write_string(ff, perf_evsel__name(evsel));
+		if (ret < 0)
+			return ret;
+		/*
+		 * write unique ids for this event
+		 */
+		ret = do_write(ff, evsel->id, evsel->ids * sizeof(u64));
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static int write_cmdline(struct feat_fd *ff,
+			 struct perf_evlist *evlist __maybe_unused)
+{
+	char buf[MAXPATHLEN];
+	u32 n;
+	int i, ret;
+
+	/* actual path to perf binary */
+	ret = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
+	if (ret <= 0)
+		return -1;
+
+	/* readlink() does not add null termination */
+	buf[ret] = '\0';
+
+	/* account for binary path */
+	n = perf_env.nr_cmdline + 1;
+
+	ret = do_write(ff, &n, sizeof(n));
+	if (ret < 0)
+		return ret;
+
+	ret = do_write_string(ff, buf);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0 ; i < perf_env.nr_cmdline; i++) {
+		ret = do_write_string(ff, perf_env.cmdline_argv[i]);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+#define CORE_SIB_FMT \
+	"/sys/devices/system/cpu/cpu%d/topology/core_siblings_list"
+#define THRD_SIB_FMT \
+	"/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list"
+
+struct cpu_topo {
+	u32 cpu_nr;
+	u32 core_sib;
+	u32 thread_sib;
+	char **core_siblings;
+	char **thread_siblings;
+};
+
+static int build_cpu_topo(struct cpu_topo *tp, int cpu)
+{
+	FILE *fp;
+	char filename[MAXPATHLEN];
+	char *buf = NULL, *p;
+	size_t len = 0;
+	ssize_t sret;
+	u32 i = 0;
+	int ret = -1;
+
+	sprintf(filename, CORE_SIB_FMT, cpu);
+	fp = fopen(filename, "r");
+	if (!fp)
+		goto try_threads;
+
+	sret = getline(&buf, &len, fp);
+	fclose(fp);
+	if (sret <= 0)
+		goto try_threads;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	for (i = 0; i < tp->core_sib; i++) {
+		if (!strcmp(buf, tp->core_siblings[i]))
+			break;
+	}
+	if (i == tp->core_sib) {
+		tp->core_siblings[i] = buf;
+		tp->core_sib++;
+		buf = NULL;
+		len = 0;
+	}
+	ret = 0;
+
+try_threads:
+	sprintf(filename, THRD_SIB_FMT, cpu);
+	fp = fopen(filename, "r");
+	if (!fp)
+		goto done;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	for (i = 0; i < tp->thread_sib; i++) {
+		if (!strcmp(buf, tp->thread_siblings[i]))
+			break;
+	}
+	if (i == tp->thread_sib) {
+		tp->thread_siblings[i] = buf;
+		tp->thread_sib++;
+		buf = NULL;
+	}
+	ret = 0;
+done:
+	if(fp)
+		fclose(fp);
+	free(buf);
+	return ret;
+}
+
+static void free_cpu_topo(struct cpu_topo *tp)
+{
+	u32 i;
+
+	if (!tp)
+		return;
+
+	for (i = 0 ; i < tp->core_sib; i++)
+		zfree(&tp->core_siblings[i]);
+
+	for (i = 0 ; i < tp->thread_sib; i++)
+		zfree(&tp->thread_siblings[i]);
+
+	free(tp);
+}
+
+static struct cpu_topo *build_cpu_topology(void)
+{
+	struct cpu_topo *tp = NULL;
+	void *addr;
+	u32 nr, i;
+	size_t sz;
+	long ncpus;
+	int ret = -1;
+	struct cpu_map *map;
+
+	ncpus = cpu__max_present_cpu();
+
+	/* build online CPU map */
+	map = cpu_map__new(NULL);
+	if (map == NULL) {
+		pr_debug("failed to get system cpumap\n");
+		return NULL;
+	}
+
+	nr = (u32)(ncpus & UINT_MAX);
+
+	sz = nr * sizeof(char *);
+	addr = calloc(1, sizeof(*tp) + 2 * sz);
+	if (!addr)
+		goto out_free;
+
+	tp = addr;
+	tp->cpu_nr = nr;
+	addr += sizeof(*tp);
+	tp->core_siblings = addr;
+	addr += sz;
+	tp->thread_siblings = addr;
+
+	for (i = 0; i < nr; i++) {
+		if (!cpu_map__has(map, i))
+			continue;
+
+		ret = build_cpu_topo(tp, i);
+		if (ret < 0)
+			break;
+	}
+
+out_free:
+	cpu_map__put(map);
+	if (ret) {
+		free_cpu_topo(tp);
+		tp = NULL;
+	}
+	return tp;
+}
+
+static int write_cpu_topology(struct feat_fd *ff,
+			      struct perf_evlist *evlist __maybe_unused)
+{
+	struct cpu_topo *tp;
+	u32 i;
+	int ret, j;
+
+	tp = build_cpu_topology();
+	if (!tp)
+		return -1;
+
+	ret = do_write(ff, &tp->core_sib, sizeof(tp->core_sib));
+	if (ret < 0)
+		goto done;
+
+	for (i = 0; i < tp->core_sib; i++) {
+		ret = do_write_string(ff, tp->core_siblings[i]);
+		if (ret < 0)
+			goto done;
+	}
+	ret = do_write(ff, &tp->thread_sib, sizeof(tp->thread_sib));
+	if (ret < 0)
+		goto done;
+
+	for (i = 0; i < tp->thread_sib; i++) {
+		ret = do_write_string(ff, tp->thread_siblings[i]);
+		if (ret < 0)
+			break;
+	}
+
+	ret = perf_env__read_cpu_topology_map(&perf_env);
+	if (ret < 0)
+		goto done;
+
+	for (j = 0; j < perf_env.nr_cpus_avail; j++) {
+		ret = do_write(ff, &perf_env.cpu[j].core_id,
+			       sizeof(perf_env.cpu[j].core_id));
+		if (ret < 0)
+			return ret;
+		ret = do_write(ff, &perf_env.cpu[j].socket_id,
+			       sizeof(perf_env.cpu[j].socket_id));
+		if (ret < 0)
+			return ret;
+	}
+done:
+	free_cpu_topo(tp);
+	return ret;
+}
+
+
+
+static int write_total_mem(struct feat_fd *ff,
+			   struct perf_evlist *evlist __maybe_unused)
+{
+	char *buf = NULL;
+	FILE *fp;
+	size_t len = 0;
+	int ret = -1, n;
+	uint64_t mem;
+
+	fp = fopen("/proc/meminfo", "r");
+	if (!fp)
+		return -1;
+
+	while (getline(&buf, &len, fp) > 0) {
+		ret = strncmp(buf, "MemTotal:", 9);
+		if (!ret)
+			break;
+	}
+	if (!ret) {
+		n = sscanf(buf, "%*s %"PRIu64, &mem);
+		if (n == 1)
+			ret = do_write(ff, &mem, sizeof(mem));
+	} else
+		ret = -1;
+	free(buf);
+	fclose(fp);
+	return ret;
+}
+
+static int write_topo_node(struct feat_fd *ff, int node)
+{
+	char str[MAXPATHLEN];
+	char field[32];
+	char *buf = NULL, *p;
+	size_t len = 0;
+	FILE *fp;
+	u64 mem_total, mem_free, mem;
+	int ret = -1;
+
+	sprintf(str, "/sys/devices/system/node/node%d/meminfo", node);
+	fp = fopen(str, "r");
+	if (!fp)
+		return -1;
+
+	while (getline(&buf, &len, fp) > 0) {
+		/* skip over invalid lines */
+		if (!strchr(buf, ':'))
+			continue;
+		if (sscanf(buf, "%*s %*d %31s %"PRIu64, field, &mem) != 2)
+			goto done;
+		if (!strcmp(field, "MemTotal:"))
+			mem_total = mem;
+		if (!strcmp(field, "MemFree:"))
+			mem_free = mem;
+	}
+
+	fclose(fp);
+	fp = NULL;
+
+	ret = do_write(ff, &mem_total, sizeof(u64));
+	if (ret)
+		goto done;
+
+	ret = do_write(ff, &mem_free, sizeof(u64));
+	if (ret)
+		goto done;
+
+	ret = -1;
+	sprintf(str, "/sys/devices/system/node/node%d/cpulist", node);
+
+	fp = fopen(str, "r");
+	if (!fp)
+		goto done;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	ret = do_write_string(ff, buf);
+done:
+	free(buf);
+	if (fp)
+		fclose(fp);
+	return ret;
+}
+
+static int write_numa_topology(struct feat_fd *ff,
+			       struct perf_evlist *evlist __maybe_unused)
+{
+	char *buf = NULL;
+	size_t len = 0;
+	FILE *fp;
+	struct cpu_map *node_map = NULL;
+	char *c;
+	u32 nr, i, j;
+	int ret = -1;
+
+	fp = fopen("/sys/devices/system/node/online", "r");
+	if (!fp)
+		return -1;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto done;
+
+	c = strchr(buf, '\n');
+	if (c)
+		*c = '\0';
+
+	node_map = cpu_map__new(buf);
+	if (!node_map)
+		goto done;
+
+	nr = (u32)node_map->nr;
+
+	ret = do_write(ff, &nr, sizeof(nr));
+	if (ret < 0)
+		goto done;
+
+	for (i = 0; i < nr; i++) {
+		j = (u32)node_map->map[i];
+		ret = do_write(ff, &j, sizeof(j));
+		if (ret < 0)
+			break;
+
+		ret = write_topo_node(ff, i);
+		if (ret < 0)
+			break;
+	}
+done:
+	free(buf);
+	fclose(fp);
+	cpu_map__put(node_map);
+	return ret;
+}
+
+/*
+ * File format:
+ *
+ * struct pmu_mappings {
+ *	u32	pmu_num;
+ *	struct pmu_map {
+ *		u32	type;
+ *		char	name[];
+ *	}[pmu_num];
+ * };
+ */
+
+static int write_pmu_mappings(struct feat_fd *ff,
+			      struct perf_evlist *evlist __maybe_unused)
+{
+	struct perf_pmu *pmu = NULL;
+	u32 pmu_num = 0;
+	int ret;
+
+	/*
+	 * Do a first pass to count number of pmu to avoid lseek so this
+	 * works in pipe mode as well.
+	 */
+	while ((pmu = perf_pmu__scan(pmu))) {
+		if (!pmu->name)
+			continue;
+		pmu_num++;
+	}
+
+	ret = do_write(ff, &pmu_num, sizeof(pmu_num));
+	if (ret < 0)
+		return ret;
+
+	while ((pmu = perf_pmu__scan(pmu))) {
+		if (!pmu->name)
+			continue;
+
+		ret = do_write(ff, &pmu->type, sizeof(pmu->type));
+		if (ret < 0)
+			return ret;
+
+		ret = do_write_string(ff, pmu->name);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * File format:
+ *
+ * struct group_descs {
+ *	u32	nr_groups;
+ *	struct group_desc {
+ *		char	name[];
+ *		u32	leader_idx;
+ *		u32	nr_members;
+ *	}[nr_groups];
+ * };
+ */
+static int write_group_desc(struct feat_fd *ff,
+			    struct perf_evlist *evlist)
+{
+	u32 nr_groups = evlist->nr_groups;
+	struct perf_evsel *evsel;
+	int ret;
+
+	ret = do_write(ff, &nr_groups, sizeof(nr_groups));
+	if (ret < 0)
+		return ret;
+
+	evlist__for_each_entry(evlist, evsel) {
+		if (perf_evsel__is_group_leader(evsel) &&
+		    evsel->nr_members > 1) {
+			const char *name = evsel->group_name ?: "{anon_group}";
+			u32 leader_idx = evsel->idx;
+			u32 nr_members = evsel->nr_members;
+
+			ret = do_write_string(ff, name);
+			if (ret < 0)
+				return ret;
+
+			ret = do_write(ff, &leader_idx, sizeof(leader_idx));
+			if (ret < 0)
+				return ret;
+
+			ret = do_write(ff, &nr_members, sizeof(nr_members));
+			if (ret < 0)
+				return ret;
+		}
+	}
+	return 0;
+}
+
+/*
+ * default get_cpuid(): nothing gets recorded
+ * actual implementation must be in arch/$(SRCARCH)/util/header.c
+ */
+int __weak get_cpuid(char *buffer __maybe_unused, size_t sz __maybe_unused)
+{
+	return -1;
+}
+
+static int write_cpuid(struct feat_fd *ff,
+		       struct perf_evlist *evlist __maybe_unused)
+{
+	char buffer[64];
+	int ret;
+
+	ret = get_cpuid(buffer, sizeof(buffer));
+	if (!ret)
+		goto write_it;
+
+	return -1;
+write_it:
+	return do_write_string(ff, buffer);
+}
+
+static int write_branch_stack(struct feat_fd *ff __maybe_unused,
+			      struct perf_evlist *evlist __maybe_unused)
+{
+	return 0;
+}
+
+static int write_auxtrace(struct feat_fd *ff,
+			  struct perf_evlist *evlist __maybe_unused)
+{
+	struct perf_session *session;
+	int err;
+
+	if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+		return -1;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	err = auxtrace_index__write(ff->fd, &session->auxtrace_index);
+	if (err < 0)
+		pr_err("Failed to write auxtrace index\n");
+	return err;
+}
+
+static int cpu_cache_level__sort(const void *a, const void *b)
+{
+	struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
+	struct cpu_cache_level *cache_b = (struct cpu_cache_level *)b;
+
+	return cache_a->level - cache_b->level;
+}
+
+static bool cpu_cache_level__cmp(struct cpu_cache_level *a, struct cpu_cache_level *b)
+{
+	if (a->level != b->level)
+		return false;
+
+	if (a->line_size != b->line_size)
+		return false;
+
+	if (a->sets != b->sets)
+		return false;
+
+	if (a->ways != b->ways)
+		return false;
+
+	if (strcmp(a->type, b->type))
+		return false;
+
+	if (strcmp(a->size, b->size))
+		return false;
+
+	if (strcmp(a->map, b->map))
+		return false;
+
+	return true;
+}
+
+static int cpu_cache_level__read(struct cpu_cache_level *cache, u32 cpu, u16 level)
+{
+	char path[PATH_MAX], file[PATH_MAX];
+	struct stat st;
+	size_t len;
+
+	scnprintf(path, PATH_MAX, "devices/system/cpu/cpu%d/cache/index%d/", cpu, level);
+	scnprintf(file, PATH_MAX, "%s/%s", sysfs__mountpoint(), path);
+
+	if (stat(file, &st))
+		return 1;
+
+	scnprintf(file, PATH_MAX, "%s/level", path);
+	if (sysfs__read_int(file, (int *) &cache->level))
+		return -1;
+
+	scnprintf(file, PATH_MAX, "%s/coherency_line_size", path);
+	if (sysfs__read_int(file, (int *) &cache->line_size))
+		return -1;
+
+	scnprintf(file, PATH_MAX, "%s/number_of_sets", path);
+	if (sysfs__read_int(file, (int *) &cache->sets))
+		return -1;
+
+	scnprintf(file, PATH_MAX, "%s/ways_of_associativity", path);
+	if (sysfs__read_int(file, (int *) &cache->ways))
+		return -1;
+
+	scnprintf(file, PATH_MAX, "%s/type", path);
+	if (sysfs__read_str(file, &cache->type, &len))
+		return -1;
+
+	cache->type[len] = 0;
+	cache->type = rtrim(cache->type);
+
+	scnprintf(file, PATH_MAX, "%s/size", path);
+	if (sysfs__read_str(file, &cache->size, &len)) {
+		free(cache->type);
+		return -1;
+	}
+
+	cache->size[len] = 0;
+	cache->size = rtrim(cache->size);
+
+	scnprintf(file, PATH_MAX, "%s/shared_cpu_list", path);
+	if (sysfs__read_str(file, &cache->map, &len)) {
+		free(cache->size);
+		free(cache->type);
+		return -1;
+	}
+
+	cache->map[len] = 0;
+	cache->map = rtrim(cache->map);
+	return 0;
+}
+
+static void cpu_cache_level__fprintf(FILE *out, struct cpu_cache_level *c)
+{
+	fprintf(out, "L%d %-15s %8s [%s]\n", c->level, c->type, c->size, c->map);
+}
+
+static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
+{
+	u32 i, cnt = 0;
+	long ncpus;
+	u32 nr, cpu;
+	u16 level;
+
+	ncpus = sysconf(_SC_NPROCESSORS_CONF);
+	if (ncpus < 0)
+		return -1;
+
+	nr = (u32)(ncpus & UINT_MAX);
+
+	for (cpu = 0; cpu < nr; cpu++) {
+		for (level = 0; level < 10; level++) {
+			struct cpu_cache_level c;
+			int err;
+
+			err = cpu_cache_level__read(&c, cpu, level);
+			if (err < 0)
+				return err;
+
+			if (err == 1)
+				break;
+
+			for (i = 0; i < cnt; i++) {
+				if (cpu_cache_level__cmp(&c, &caches[i]))
+					break;
+			}
+
+			if (i == cnt)
+				caches[cnt++] = c;
+			else
+				cpu_cache_level__free(&c);
+
+			if (WARN_ONCE(cnt == size, "way too many cpu caches.."))
+				goto out;
+		}
+	}
+ out:
+	*cntp = cnt;
+	return 0;
+}
+
+#define MAX_CACHES (MAX_NR_CPUS * 4)
+
+static int write_cache(struct feat_fd *ff,
+		       struct perf_evlist *evlist __maybe_unused)
+{
+	struct cpu_cache_level caches[MAX_CACHES];
+	u32 cnt = 0, i, version = 1;
+	int ret;
+
+	ret = build_caches(caches, MAX_CACHES, &cnt);
+	if (ret)
+		goto out;
+
+	qsort(&caches, cnt, sizeof(struct cpu_cache_level), cpu_cache_level__sort);
+
+	ret = do_write(ff, &version, sizeof(u32));
+	if (ret < 0)
+		goto out;
+
+	ret = do_write(ff, &cnt, sizeof(u32));
+	if (ret < 0)
+		goto out;
+
+	for (i = 0; i < cnt; i++) {
+		struct cpu_cache_level *c = &caches[i];
+
+		#define _W(v)					\
+			ret = do_write(ff, &c->v, sizeof(u32));	\
+			if (ret < 0)				\
+				goto out;
+
+		_W(level)
+		_W(line_size)
+		_W(sets)
+		_W(ways)
+		#undef _W
+
+		#define _W(v)						\
+			ret = do_write_string(ff, (const char *) c->v);	\
+			if (ret < 0)					\
+				goto out;
+
+		_W(type)
+		_W(size)
+		_W(map)
+		#undef _W
+	}
+
+out:
+	for (i = 0; i < cnt; i++)
+		cpu_cache_level__free(&caches[i]);
+	return ret;
+}
+
+static int write_stat(struct feat_fd *ff __maybe_unused,
+		      struct perf_evlist *evlist __maybe_unused)
+{
+	return 0;
+}
+
+static int write_sample_time(struct feat_fd *ff,
+			     struct perf_evlist *evlist)
+{
+	int ret;
+
+	ret = do_write(ff, &evlist->first_sample_time,
+		       sizeof(evlist->first_sample_time));
+	if (ret < 0)
+		return ret;
+
+	return do_write(ff, &evlist->last_sample_time,
+			sizeof(evlist->last_sample_time));
+}
+
+
+static int memory_node__read(struct memory_node *n, unsigned long idx)
+{
+	unsigned int phys, size = 0;
+	char path[PATH_MAX];
+	struct dirent *ent;
+	DIR *dir;
+
+#define for_each_memory(mem, dir)					\
+	while ((ent = readdir(dir)))					\
+		if (strcmp(ent->d_name, ".") &&				\
+		    strcmp(ent->d_name, "..") &&			\
+		    sscanf(ent->d_name, "memory%u", &mem) == 1)
+
+	scnprintf(path, PATH_MAX,
+		  "%s/devices/system/node/node%lu",
+		  sysfs__mountpoint(), idx);
+
+	dir = opendir(path);
+	if (!dir) {
+		pr_warning("failed: cant' open memory sysfs data\n");
+		return -1;
+	}
+
+	for_each_memory(phys, dir) {
+		size = max(phys, size);
+	}
+
+	size++;
+
+	n->set = bitmap_alloc(size);
+	if (!n->set) {
+		closedir(dir);
+		return -ENOMEM;
+	}
+
+	n->node = idx;
+	n->size = size;
+
+	rewinddir(dir);
+
+	for_each_memory(phys, dir) {
+		set_bit(phys, n->set);
+	}
+
+	closedir(dir);
+	return 0;
+}
+
+static int memory_node__sort(const void *a, const void *b)
+{
+	const struct memory_node *na = a;
+	const struct memory_node *nb = b;
+
+	return na->node - nb->node;
+}
+
+static int build_mem_topology(struct memory_node *nodes, u64 size, u64 *cntp)
+{
+	char path[PATH_MAX];
+	struct dirent *ent;
+	DIR *dir;
+	u64 cnt = 0;
+	int ret = 0;
+
+	scnprintf(path, PATH_MAX, "%s/devices/system/node/",
+		  sysfs__mountpoint());
+
+	dir = opendir(path);
+	if (!dir) {
+		pr_debug2("%s: could't read %s, does this arch have topology information?\n",
+			  __func__, path);
+		return -1;
+	}
+
+	while (!ret && (ent = readdir(dir))) {
+		unsigned int idx;
+		int r;
+
+		if (!strcmp(ent->d_name, ".") ||
+		    !strcmp(ent->d_name, ".."))
+			continue;
+
+		r = sscanf(ent->d_name, "node%u", &idx);
+		if (r != 1)
+			continue;
+
+		if (WARN_ONCE(cnt >= size,
+			      "failed to write MEM_TOPOLOGY, way too many nodes\n"))
+			return -1;
+
+		ret = memory_node__read(&nodes[cnt++], idx);
+	}
+
+	*cntp = cnt;
+	closedir(dir);
+
+	if (!ret)
+		qsort(nodes, cnt, sizeof(nodes[0]), memory_node__sort);
+
+	return ret;
+}
+
+#define MAX_MEMORY_NODES 2000
+
+/*
+ * The MEM_TOPOLOGY holds physical memory map for every
+ * node in system. The format of data is as follows:
+ *
+ *  0 - version          | for future changes
+ *  8 - block_size_bytes | /sys/devices/system/memory/block_size_bytes
+ * 16 - count            | number of nodes
+ *
+ * For each node we store map of physical indexes for
+ * each node:
+ *
+ * 32 - node id          | node index
+ * 40 - size             | size of bitmap
+ * 48 - bitmap           | bitmap of memory indexes that belongs to node
+ */
+static int write_mem_topology(struct feat_fd *ff __maybe_unused,
+			      struct perf_evlist *evlist __maybe_unused)
+{
+	static struct memory_node nodes[MAX_MEMORY_NODES];
+	u64 bsize, version = 1, i, nr;
+	int ret;
+
+	ret = sysfs__read_xll("devices/system/memory/block_size_bytes",
+			      (unsigned long long *) &bsize);
+	if (ret)
+		return ret;
+
+	ret = build_mem_topology(&nodes[0], MAX_MEMORY_NODES, &nr);
+	if (ret)
+		return ret;
+
+	ret = do_write(ff, &version, sizeof(version));
+	if (ret < 0)
+		goto out;
+
+	ret = do_write(ff, &bsize, sizeof(bsize));
+	if (ret < 0)
+		goto out;
+
+	ret = do_write(ff, &nr, sizeof(nr));
+	if (ret < 0)
+		goto out;
+
+	for (i = 0; i < nr; i++) {
+		struct memory_node *n = &nodes[i];
+
+		#define _W(v)						\
+			ret = do_write(ff, &n->v, sizeof(n->v));	\
+			if (ret < 0)					\
+				goto out;
+
+		_W(node)
+		_W(size)
+
+		#undef _W
+
+		ret = do_write_bitmap(ff, n->set, n->size);
+		if (ret < 0)
+			goto out;
+	}
+
+out:
+	return ret;
+}
+
+static void print_hostname(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# hostname : %s\n", ff->ph->env.hostname);
+}
+
+static void print_osrelease(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# os release : %s\n", ff->ph->env.os_release);
+}
+
+static void print_arch(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# arch : %s\n", ff->ph->env.arch);
+}
+
+static void print_cpudesc(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# cpudesc : %s\n", ff->ph->env.cpu_desc);
+}
+
+static void print_nrcpus(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# nrcpus online : %u\n", ff->ph->env.nr_cpus_online);
+	fprintf(fp, "# nrcpus avail : %u\n", ff->ph->env.nr_cpus_avail);
+}
+
+static void print_version(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# perf version : %s\n", ff->ph->env.version);
+}
+
+static void print_cmdline(struct feat_fd *ff, FILE *fp)
+{
+	int nr, i;
+
+	nr = ff->ph->env.nr_cmdline;
+
+	fprintf(fp, "# cmdline : ");
+
+	for (i = 0; i < nr; i++) {
+		char *argv_i = strdup(ff->ph->env.cmdline_argv[i]);
+		if (!argv_i) {
+			fprintf(fp, "%s ", ff->ph->env.cmdline_argv[i]);
+		} else {
+			char *mem = argv_i;
+			do {
+				char *quote = strchr(argv_i, '\'');
+				if (!quote)
+					break;
+				*quote++ = '\0';
+				fprintf(fp, "%s\\\'", argv_i);
+				argv_i = quote;
+			} while (1);
+			fprintf(fp, "%s ", argv_i);
+			free(mem);
+		}
+	}
+	fputc('\n', fp);
+}
+
+static void print_cpu_topology(struct feat_fd *ff, FILE *fp)
+{
+	struct perf_header *ph = ff->ph;
+	int cpu_nr = ph->env.nr_cpus_avail;
+	int nr, i;
+	char *str;
+
+	nr = ph->env.nr_sibling_cores;
+	str = ph->env.sibling_cores;
+
+	for (i = 0; i < nr; i++) {
+		fprintf(fp, "# sibling cores   : %s\n", str);
+		str += strlen(str) + 1;
+	}
+
+	nr = ph->env.nr_sibling_threads;
+	str = ph->env.sibling_threads;
+
+	for (i = 0; i < nr; i++) {
+		fprintf(fp, "# sibling threads : %s\n", str);
+		str += strlen(str) + 1;
+	}
+
+	if (ph->env.cpu != NULL) {
+		for (i = 0; i < cpu_nr; i++)
+			fprintf(fp, "# CPU %d: Core ID %d, Socket ID %d\n", i,
+				ph->env.cpu[i].core_id, ph->env.cpu[i].socket_id);
+	} else
+		fprintf(fp, "# Core ID and Socket ID information is not available\n");
+}
+
+static void free_event_desc(struct perf_evsel *events)
+{
+	struct perf_evsel *evsel;
+
+	if (!events)
+		return;
+
+	for (evsel = events; evsel->attr.size; evsel++) {
+		zfree(&evsel->name);
+		zfree(&evsel->id);
+	}
+
+	free(events);
+}
+
+static struct perf_evsel *read_event_desc(struct feat_fd *ff)
+{
+	struct perf_evsel *evsel, *events = NULL;
+	u64 *id;
+	void *buf = NULL;
+	u32 nre, sz, nr, i, j;
+	size_t msz;
+
+	/* number of events */
+	if (do_read_u32(ff, &nre))
+		goto error;
+
+	if (do_read_u32(ff, &sz))
+		goto error;
+
+	/* buffer to hold on file attr struct */
+	buf = malloc(sz);
+	if (!buf)
+		goto error;
+
+	/* the last event terminates with evsel->attr.size == 0: */
+	events = calloc(nre + 1, sizeof(*events));
+	if (!events)
+		goto error;
+
+	msz = sizeof(evsel->attr);
+	if (sz < msz)
+		msz = sz;
+
+	for (i = 0, evsel = events; i < nre; evsel++, i++) {
+		evsel->idx = i;
+
+		/*
+		 * must read entire on-file attr struct to
+		 * sync up with layout.
+		 */
+		if (__do_read(ff, buf, sz))
+			goto error;
+
+		if (ff->ph->needs_swap)
+			perf_event__attr_swap(buf);
+
+		memcpy(&evsel->attr, buf, msz);
+
+		if (do_read_u32(ff, &nr))
+			goto error;
+
+		if (ff->ph->needs_swap)
+			evsel->needs_swap = true;
+
+		evsel->name = do_read_string(ff);
+		if (!evsel->name)
+			goto error;
+
+		if (!nr)
+			continue;
+
+		id = calloc(nr, sizeof(*id));
+		if (!id)
+			goto error;
+		evsel->ids = nr;
+		evsel->id = id;
+
+		for (j = 0 ; j < nr; j++) {
+			if (do_read_u64(ff, id))
+				goto error;
+			id++;
+		}
+	}
+out:
+	free(buf);
+	return events;
+error:
+	free_event_desc(events);
+	events = NULL;
+	goto out;
+}
+
+static int __desc_attr__fprintf(FILE *fp, const char *name, const char *val,
+				void *priv __maybe_unused)
+{
+	return fprintf(fp, ", %s = %s", name, val);
+}
+
+static void print_event_desc(struct feat_fd *ff, FILE *fp)
+{
+	struct perf_evsel *evsel, *events;
+	u32 j;
+	u64 *id;
+
+	if (ff->events)
+		events = ff->events;
+	else
+		events = read_event_desc(ff);
+
+	if (!events) {
+		fprintf(fp, "# event desc: not available or unable to read\n");
+		return;
+	}
+
+	for (evsel = events; evsel->attr.size; evsel++) {
+		fprintf(fp, "# event : name = %s, ", evsel->name);
+
+		if (evsel->ids) {
+			fprintf(fp, ", id = {");
+			for (j = 0, id = evsel->id; j < evsel->ids; j++, id++) {
+				if (j)
+					fputc(',', fp);
+				fprintf(fp, " %"PRIu64, *id);
+			}
+			fprintf(fp, " }");
+		}
+
+		perf_event_attr__fprintf(fp, &evsel->attr, __desc_attr__fprintf, NULL);
+
+		fputc('\n', fp);
+	}
+
+	free_event_desc(events);
+	ff->events = NULL;
+}
+
+static void print_total_mem(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# total memory : %llu kB\n", ff->ph->env.total_mem);
+}
+
+static void print_numa_topology(struct feat_fd *ff, FILE *fp)
+{
+	int i;
+	struct numa_node *n;
+
+	for (i = 0; i < ff->ph->env.nr_numa_nodes; i++) {
+		n = &ff->ph->env.numa_nodes[i];
+
+		fprintf(fp, "# node%u meminfo  : total = %"PRIu64" kB,"
+			    " free = %"PRIu64" kB\n",
+			n->node, n->mem_total, n->mem_free);
+
+		fprintf(fp, "# node%u cpu list : ", n->node);
+		cpu_map__fprintf(n->map, fp);
+	}
+}
+
+static void print_cpuid(struct feat_fd *ff, FILE *fp)
+{
+	fprintf(fp, "# cpuid : %s\n", ff->ph->env.cpuid);
+}
+
+static void print_branch_stack(struct feat_fd *ff __maybe_unused, FILE *fp)
+{
+	fprintf(fp, "# contains samples with branch stack\n");
+}
+
+static void print_auxtrace(struct feat_fd *ff __maybe_unused, FILE *fp)
+{
+	fprintf(fp, "# contains AUX area data (e.g. instruction trace)\n");
+}
+
+static void print_stat(struct feat_fd *ff __maybe_unused, FILE *fp)
+{
+	fprintf(fp, "# contains stat data\n");
+}
+
+static void print_cache(struct feat_fd *ff, FILE *fp __maybe_unused)
+{
+	int i;
+
+	fprintf(fp, "# CPU cache info:\n");
+	for (i = 0; i < ff->ph->env.caches_cnt; i++) {
+		fprintf(fp, "#  ");
+		cpu_cache_level__fprintf(fp, &ff->ph->env.caches[i]);
+	}
+}
+
+static void print_pmu_mappings(struct feat_fd *ff, FILE *fp)
+{
+	const char *delimiter = "# pmu mappings: ";
+	char *str, *tmp;
+	u32 pmu_num;
+	u32 type;
+
+	pmu_num = ff->ph->env.nr_pmu_mappings;
+	if (!pmu_num) {
+		fprintf(fp, "# pmu mappings: not available\n");
+		return;
+	}
+
+	str = ff->ph->env.pmu_mappings;
+
+	while (pmu_num) {
+		type = strtoul(str, &tmp, 0);
+		if (*tmp != ':')
+			goto error;
+
+		str = tmp + 1;
+		fprintf(fp, "%s%s = %" PRIu32, delimiter, str, type);
+
+		delimiter = ", ";
+		str += strlen(str) + 1;
+		pmu_num--;
+	}
+
+	fprintf(fp, "\n");
+
+	if (!pmu_num)
+		return;
+error:
+	fprintf(fp, "# pmu mappings: unable to read\n");
+}
+
+static void print_group_desc(struct feat_fd *ff, FILE *fp)
+{
+	struct perf_session *session;
+	struct perf_evsel *evsel;
+	u32 nr = 0;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	evlist__for_each_entry(session->evlist, evsel) {
+		if (perf_evsel__is_group_leader(evsel) &&
+		    evsel->nr_members > 1) {
+			fprintf(fp, "# group: %s{%s", evsel->group_name ?: "",
+				perf_evsel__name(evsel));
+
+			nr = evsel->nr_members - 1;
+		} else if (nr) {
+			fprintf(fp, ",%s", perf_evsel__name(evsel));
+
+			if (--nr == 0)
+				fprintf(fp, "}\n");
+		}
+	}
+}
+
+static void print_sample_time(struct feat_fd *ff, FILE *fp)
+{
+	struct perf_session *session;
+	char time_buf[32];
+	double d;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	timestamp__scnprintf_usec(session->evlist->first_sample_time,
+				  time_buf, sizeof(time_buf));
+	fprintf(fp, "# time of first sample : %s\n", time_buf);
+
+	timestamp__scnprintf_usec(session->evlist->last_sample_time,
+				  time_buf, sizeof(time_buf));
+	fprintf(fp, "# time of last sample : %s\n", time_buf);
+
+	d = (double)(session->evlist->last_sample_time -
+		session->evlist->first_sample_time) / NSEC_PER_MSEC;
+
+	fprintf(fp, "# sample duration : %10.3f ms\n", d);
+}
+
+static void memory_node__fprintf(struct memory_node *n,
+				 unsigned long long bsize, FILE *fp)
+{
+	char buf_map[100], buf_size[50];
+	unsigned long long size;
+
+	size = bsize * bitmap_weight(n->set, n->size);
+	unit_number__scnprintf(buf_size, 50, size);
+
+	bitmap_scnprintf(n->set, n->size, buf_map, 100);
+	fprintf(fp, "#  %3" PRIu64 " [%s]: %s\n", n->node, buf_size, buf_map);
+}
+
+static void print_mem_topology(struct feat_fd *ff, FILE *fp)
+{
+	struct memory_node *nodes;
+	int i, nr;
+
+	nodes = ff->ph->env.memory_nodes;
+	nr    = ff->ph->env.nr_memory_nodes;
+
+	fprintf(fp, "# memory nodes (nr %d, block size 0x%llx):\n",
+		nr, ff->ph->env.memory_bsize);
+
+	for (i = 0; i < nr; i++) {
+		memory_node__fprintf(&nodes[i], ff->ph->env.memory_bsize, fp);
+	}
+}
+
+static int __event_process_build_id(struct build_id_event *bev,
+				    char *filename,
+				    struct perf_session *session)
+{
+	int err = -1;
+	struct machine *machine;
+	u16 cpumode;
+	struct dso *dso;
+	enum dso_kernel_type dso_type;
+
+	machine = perf_session__findnew_machine(session, bev->pid);
+	if (!machine)
+		goto out;
+
+	cpumode = bev->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+
+	switch (cpumode) {
+	case PERF_RECORD_MISC_KERNEL:
+		dso_type = DSO_TYPE_KERNEL;
+		break;
+	case PERF_RECORD_MISC_GUEST_KERNEL:
+		dso_type = DSO_TYPE_GUEST_KERNEL;
+		break;
+	case PERF_RECORD_MISC_USER:
+	case PERF_RECORD_MISC_GUEST_USER:
+		dso_type = DSO_TYPE_USER;
+		break;
+	default:
+		goto out;
+	}
+
+	dso = machine__findnew_dso(machine, filename);
+	if (dso != NULL) {
+		char sbuild_id[SBUILD_ID_SIZE];
+
+		dso__set_build_id(dso, &bev->build_id);
+
+		if (dso_type != DSO_TYPE_USER) {
+			struct kmod_path m = { .name = NULL, };
+
+			if (!kmod_path__parse_name(&m, filename) && m.kmod)
+				dso__set_module_info(dso, &m, machine);
+			else
+				dso->kernel = dso_type;
+
+			free(m.name);
+		}
+
+		build_id__sprintf(dso->build_id, sizeof(dso->build_id),
+				  sbuild_id);
+		pr_debug("build id event received for %s: %s\n",
+			 dso->long_name, sbuild_id);
+		dso__put(dso);
+	}
+
+	err = 0;
+out:
+	return err;
+}
+
+static int perf_header__read_build_ids_abi_quirk(struct perf_header *header,
+						 int input, u64 offset, u64 size)
+{
+	struct perf_session *session = container_of(header, struct perf_session, header);
+	struct {
+		struct perf_event_header   header;
+		u8			   build_id[PERF_ALIGN(BUILD_ID_SIZE, sizeof(u64))];
+		char			   filename[0];
+	} old_bev;
+	struct build_id_event bev;
+	char filename[PATH_MAX];
+	u64 limit = offset + size;
+
+	while (offset < limit) {
+		ssize_t len;
+
+		if (readn(input, &old_bev, sizeof(old_bev)) != sizeof(old_bev))
+			return -1;
+
+		if (header->needs_swap)
+			perf_event_header__bswap(&old_bev.header);
+
+		len = old_bev.header.size - sizeof(old_bev);
+		if (readn(input, filename, len) != len)
+			return -1;
+
+		bev.header = old_bev.header;
+
+		/*
+		 * As the pid is the missing value, we need to fill
+		 * it properly. The header.misc value give us nice hint.
+		 */
+		bev.pid	= HOST_KERNEL_ID;
+		if (bev.header.misc == PERF_RECORD_MISC_GUEST_USER ||
+		    bev.header.misc == PERF_RECORD_MISC_GUEST_KERNEL)
+			bev.pid	= DEFAULT_GUEST_KERNEL_ID;
+
+		memcpy(bev.build_id, old_bev.build_id, sizeof(bev.build_id));
+		__event_process_build_id(&bev, filename, session);
+
+		offset += bev.header.size;
+	}
+
+	return 0;
+}
+
+static int perf_header__read_build_ids(struct perf_header *header,
+				       int input, u64 offset, u64 size)
+{
+	struct perf_session *session = container_of(header, struct perf_session, header);
+	struct build_id_event bev;
+	char filename[PATH_MAX];
+	u64 limit = offset + size, orig_offset = offset;
+	int err = -1;
+
+	while (offset < limit) {
+		ssize_t len;
+
+		if (readn(input, &bev, sizeof(bev)) != sizeof(bev))
+			goto out;
+
+		if (header->needs_swap)
+			perf_event_header__bswap(&bev.header);
+
+		len = bev.header.size - sizeof(bev);
+		if (readn(input, filename, len) != len)
+			goto out;
+		/*
+		 * The a1645ce1 changeset:
+		 *
+		 * "perf: 'perf kvm' tool for monitoring guest performance from host"
+		 *
+		 * Added a field to struct build_id_event that broke the file
+		 * format.
+		 *
+		 * Since the kernel build-id is the first entry, process the
+		 * table using the old format if the well known
+		 * '[kernel.kallsyms]' string for the kernel build-id has the
+		 * first 4 characters chopped off (where the pid_t sits).
+		 */
+		if (memcmp(filename, "nel.kallsyms]", 13) == 0) {
+			if (lseek(input, orig_offset, SEEK_SET) == (off_t)-1)
+				return -1;
+			return perf_header__read_build_ids_abi_quirk(header, input, offset, size);
+		}
+
+		__event_process_build_id(&bev, filename, session);
+
+		offset += bev.header.size;
+	}
+	err = 0;
+out:
+	return err;
+}
+
+/* Macro for features that simply need to read and store a string. */
+#define FEAT_PROCESS_STR_FUN(__feat, __feat_env) \
+static int process_##__feat(struct feat_fd *ff, void *data __maybe_unused) \
+{\
+	ff->ph->env.__feat_env = do_read_string(ff); \
+	return ff->ph->env.__feat_env ? 0 : -ENOMEM; \
+}
+
+FEAT_PROCESS_STR_FUN(hostname, hostname);
+FEAT_PROCESS_STR_FUN(osrelease, os_release);
+FEAT_PROCESS_STR_FUN(version, version);
+FEAT_PROCESS_STR_FUN(arch, arch);
+FEAT_PROCESS_STR_FUN(cpudesc, cpu_desc);
+FEAT_PROCESS_STR_FUN(cpuid, cpuid);
+
+static int process_tracing_data(struct feat_fd *ff, void *data)
+{
+	ssize_t ret = trace_report(ff->fd, data, false);
+
+	return ret < 0 ? -1 : 0;
+}
+
+static int process_build_id(struct feat_fd *ff, void *data __maybe_unused)
+{
+	if (perf_header__read_build_ids(ff->ph, ff->fd, ff->offset, ff->size))
+		pr_debug("Failed to read buildids, continuing...\n");
+	return 0;
+}
+
+static int process_nrcpus(struct feat_fd *ff, void *data __maybe_unused)
+{
+	int ret;
+	u32 nr_cpus_avail, nr_cpus_online;
+
+	ret = do_read_u32(ff, &nr_cpus_avail);
+	if (ret)
+		return ret;
+
+	ret = do_read_u32(ff, &nr_cpus_online);
+	if (ret)
+		return ret;
+	ff->ph->env.nr_cpus_avail = (int)nr_cpus_avail;
+	ff->ph->env.nr_cpus_online = (int)nr_cpus_online;
+	return 0;
+}
+
+static int process_total_mem(struct feat_fd *ff, void *data __maybe_unused)
+{
+	u64 total_mem;
+	int ret;
+
+	ret = do_read_u64(ff, &total_mem);
+	if (ret)
+		return -1;
+	ff->ph->env.total_mem = (unsigned long long)total_mem;
+	return 0;
+}
+
+static struct perf_evsel *
+perf_evlist__find_by_index(struct perf_evlist *evlist, int idx)
+{
+	struct perf_evsel *evsel;
+
+	evlist__for_each_entry(evlist, evsel) {
+		if (evsel->idx == idx)
+			return evsel;
+	}
+
+	return NULL;
+}
+
+static void
+perf_evlist__set_event_name(struct perf_evlist *evlist,
+			    struct perf_evsel *event)
+{
+	struct perf_evsel *evsel;
+
+	if (!event->name)
+		return;
+
+	evsel = perf_evlist__find_by_index(evlist, event->idx);
+	if (!evsel)
+		return;
+
+	if (evsel->name)
+		return;
+
+	evsel->name = strdup(event->name);
+}
+
+static int
+process_event_desc(struct feat_fd *ff, void *data __maybe_unused)
+{
+	struct perf_session *session;
+	struct perf_evsel *evsel, *events = read_event_desc(ff);
+
+	if (!events)
+		return 0;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	if (session->data->is_pipe) {
+		/* Save events for reading later by print_event_desc,
+		 * since they can't be read again in pipe mode. */
+		ff->events = events;
+	}
+
+	for (evsel = events; evsel->attr.size; evsel++)
+		perf_evlist__set_event_name(session->evlist, evsel);
+
+	if (!session->data->is_pipe)
+		free_event_desc(events);
+
+	return 0;
+}
+
+static int process_cmdline(struct feat_fd *ff, void *data __maybe_unused)
+{
+	char *str, *cmdline = NULL, **argv = NULL;
+	u32 nr, i, len = 0;
+
+	if (do_read_u32(ff, &nr))
+		return -1;
+
+	ff->ph->env.nr_cmdline = nr;
+
+	cmdline = zalloc(ff->size + nr + 1);
+	if (!cmdline)
+		return -1;
+
+	argv = zalloc(sizeof(char *) * (nr + 1));
+	if (!argv)
+		goto error;
+
+	for (i = 0; i < nr; i++) {
+		str = do_read_string(ff);
+		if (!str)
+			goto error;
+
+		argv[i] = cmdline + len;
+		memcpy(argv[i], str, strlen(str) + 1);
+		len += strlen(str) + 1;
+		free(str);
+	}
+	ff->ph->env.cmdline = cmdline;
+	ff->ph->env.cmdline_argv = (const char **) argv;
+	return 0;
+
+error:
+	free(argv);
+	free(cmdline);
+	return -1;
+}
+
+static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
+{
+	u32 nr, i;
+	char *str;
+	struct strbuf sb;
+	int cpu_nr = ff->ph->env.nr_cpus_avail;
+	u64 size = 0;
+	struct perf_header *ph = ff->ph;
+	bool do_core_id_test = true;
+
+	ph->env.cpu = calloc(cpu_nr, sizeof(*ph->env.cpu));
+	if (!ph->env.cpu)
+		return -1;
+
+	if (do_read_u32(ff, &nr))
+		goto free_cpu;
+
+	ph->env.nr_sibling_cores = nr;
+	size += sizeof(u32);
+	if (strbuf_init(&sb, 128) < 0)
+		goto free_cpu;
+
+	for (i = 0; i < nr; i++) {
+		str = do_read_string(ff);
+		if (!str)
+			goto error;
+
+		/* include a NULL character at the end */
+		if (strbuf_add(&sb, str, strlen(str) + 1) < 0)
+			goto error;
+		size += string_size(str);
+		free(str);
+	}
+	ph->env.sibling_cores = strbuf_detach(&sb, NULL);
+
+	if (do_read_u32(ff, &nr))
+		return -1;
+
+	ph->env.nr_sibling_threads = nr;
+	size += sizeof(u32);
+
+	for (i = 0; i < nr; i++) {
+		str = do_read_string(ff);
+		if (!str)
+			goto error;
+
+		/* include a NULL character at the end */
+		if (strbuf_add(&sb, str, strlen(str) + 1) < 0)
+			goto error;
+		size += string_size(str);
+		free(str);
+	}
+	ph->env.sibling_threads = strbuf_detach(&sb, NULL);
+
+	/*
+	 * The header may be from old perf,
+	 * which doesn't include core id and socket id information.
+	 */
+	if (ff->size <= size) {
+		zfree(&ph->env.cpu);
+		return 0;
+	}
+
+	/* On s390 the socket_id number is not related to the numbers of cpus.
+	 * The socket_id number might be higher than the numbers of cpus.
+	 * This depends on the configuration.
+	 * AArch64 is the same.
+	 */
+	if (ph->env.arch && (!strncmp(ph->env.arch, "s390", 4)
+			  || !strncmp(ph->env.arch, "aarch64", 7)))
+		do_core_id_test = false;
+
+	for (i = 0; i < (u32)cpu_nr; i++) {
+		if (do_read_u32(ff, &nr))
+			goto free_cpu;
+
+		ph->env.cpu[i].core_id = nr;
+
+		if (do_read_u32(ff, &nr))
+			goto free_cpu;
+
+		if (do_core_id_test && nr != (u32)-1 && nr > (u32)cpu_nr) {
+			pr_debug("socket_id number is too big."
+				 "You may need to upgrade the perf tool.\n");
+			goto free_cpu;
+		}
+
+		ph->env.cpu[i].socket_id = nr;
+	}
+
+	return 0;
+
+error:
+	strbuf_release(&sb);
+free_cpu:
+	zfree(&ph->env.cpu);
+	return -1;
+}
+
+static int process_numa_topology(struct feat_fd *ff, void *data __maybe_unused)
+{
+	struct numa_node *nodes, *n;
+	u32 nr, i;
+	char *str;
+
+	/* nr nodes */
+	if (do_read_u32(ff, &nr))
+		return -1;
+
+	nodes = zalloc(sizeof(*nodes) * nr);
+	if (!nodes)
+		return -ENOMEM;
+
+	for (i = 0; i < nr; i++) {
+		n = &nodes[i];
+
+		/* node number */
+		if (do_read_u32(ff, &n->node))
+			goto error;
+
+		if (do_read_u64(ff, &n->mem_total))
+			goto error;
+
+		if (do_read_u64(ff, &n->mem_free))
+			goto error;
+
+		str = do_read_string(ff);
+		if (!str)
+			goto error;
+
+		n->map = cpu_map__new(str);
+		if (!n->map)
+			goto error;
+
+		free(str);
+	}
+	ff->ph->env.nr_numa_nodes = nr;
+	ff->ph->env.numa_nodes = nodes;
+	return 0;
+
+error:
+	free(nodes);
+	return -1;
+}
+
+static int process_pmu_mappings(struct feat_fd *ff, void *data __maybe_unused)
+{
+	char *name;
+	u32 pmu_num;
+	u32 type;
+	struct strbuf sb;
+
+	if (do_read_u32(ff, &pmu_num))
+		return -1;
+
+	if (!pmu_num) {
+		pr_debug("pmu mappings not available\n");
+		return 0;
+	}
+
+	ff->ph->env.nr_pmu_mappings = pmu_num;
+	if (strbuf_init(&sb, 128) < 0)
+		return -1;
+
+	while (pmu_num) {
+		if (do_read_u32(ff, &type))
+			goto error;
+
+		name = do_read_string(ff);
+		if (!name)
+			goto error;
+
+		if (strbuf_addf(&sb, "%u:%s", type, name) < 0)
+			goto error;
+		/* include a NULL character at the end */
+		if (strbuf_add(&sb, "", 1) < 0)
+			goto error;
+
+		if (!strcmp(name, "msr"))
+			ff->ph->env.msr_pmu_type = type;
+
+		free(name);
+		pmu_num--;
+	}
+	ff->ph->env.pmu_mappings = strbuf_detach(&sb, NULL);
+	return 0;
+
+error:
+	strbuf_release(&sb);
+	return -1;
+}
+
+static int process_group_desc(struct feat_fd *ff, void *data __maybe_unused)
+{
+	size_t ret = -1;
+	u32 i, nr, nr_groups;
+	struct perf_session *session;
+	struct perf_evsel *evsel, *leader = NULL;
+	struct group_desc {
+		char *name;
+		u32 leader_idx;
+		u32 nr_members;
+	} *desc;
+
+	if (do_read_u32(ff, &nr_groups))
+		return -1;
+
+	ff->ph->env.nr_groups = nr_groups;
+	if (!nr_groups) {
+		pr_debug("group desc not available\n");
+		return 0;
+	}
+
+	desc = calloc(nr_groups, sizeof(*desc));
+	if (!desc)
+		return -1;
+
+	for (i = 0; i < nr_groups; i++) {
+		desc[i].name = do_read_string(ff);
+		if (!desc[i].name)
+			goto out_free;
+
+		if (do_read_u32(ff, &desc[i].leader_idx))
+			goto out_free;
+
+		if (do_read_u32(ff, &desc[i].nr_members))
+			goto out_free;
+	}
+
+	/*
+	 * Rebuild group relationship based on the group_desc
+	 */
+	session = container_of(ff->ph, struct perf_session, header);
+	session->evlist->nr_groups = nr_groups;
+
+	i = nr = 0;
+	evlist__for_each_entry(session->evlist, evsel) {
+		if (evsel->idx == (int) desc[i].leader_idx) {
+			evsel->leader = evsel;
+			/* {anon_group} is a dummy name */
+			if (strcmp(desc[i].name, "{anon_group}")) {
+				evsel->group_name = desc[i].name;
+				desc[i].name = NULL;
+			}
+			evsel->nr_members = desc[i].nr_members;
+
+			if (i >= nr_groups || nr > 0) {
+				pr_debug("invalid group desc\n");
+				goto out_free;
+			}
+
+			leader = evsel;
+			nr = evsel->nr_members - 1;
+			i++;
+		} else if (nr) {
+			/* This is a group member */
+			evsel->leader = leader;
+
+			nr--;
+		}
+	}
+
+	if (i != nr_groups || nr != 0) {
+		pr_debug("invalid group desc\n");
+		goto out_free;
+	}
+
+	ret = 0;
+out_free:
+	for (i = 0; i < nr_groups; i++)
+		zfree(&desc[i].name);
+	free(desc);
+
+	return ret;
+}
+
+static int process_auxtrace(struct feat_fd *ff, void *data __maybe_unused)
+{
+	struct perf_session *session;
+	int err;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	err = auxtrace_index__process(ff->fd, ff->size, session,
+				      ff->ph->needs_swap);
+	if (err < 0)
+		pr_err("Failed to process auxtrace index\n");
+	return err;
+}
+
+static int process_cache(struct feat_fd *ff, void *data __maybe_unused)
+{
+	struct cpu_cache_level *caches;
+	u32 cnt, i, version;
+
+	if (do_read_u32(ff, &version))
+		return -1;
+
+	if (version != 1)
+		return -1;
+
+	if (do_read_u32(ff, &cnt))
+		return -1;
+
+	caches = zalloc(sizeof(*caches) * cnt);
+	if (!caches)
+		return -1;
+
+	for (i = 0; i < cnt; i++) {
+		struct cpu_cache_level c;
+
+		#define _R(v)						\
+			if (do_read_u32(ff, &c.v))\
+				goto out_free_caches;			\
+
+		_R(level)
+		_R(line_size)
+		_R(sets)
+		_R(ways)
+		#undef _R
+
+		#define _R(v)					\
+			c.v = do_read_string(ff);		\
+			if (!c.v)				\
+				goto out_free_caches;
+
+		_R(type)
+		_R(size)
+		_R(map)
+		#undef _R
+
+		caches[i] = c;
+	}
+
+	ff->ph->env.caches = caches;
+	ff->ph->env.caches_cnt = cnt;
+	return 0;
+out_free_caches:
+	free(caches);
+	return -1;
+}
+
+static int process_sample_time(struct feat_fd *ff, void *data __maybe_unused)
+{
+	struct perf_session *session;
+	u64 first_sample_time, last_sample_time;
+	int ret;
+
+	session = container_of(ff->ph, struct perf_session, header);
+
+	ret = do_read_u64(ff, &first_sample_time);
+	if (ret)
+		return -1;
+
+	ret = do_read_u64(ff, &last_sample_time);
+	if (ret)
+		return -1;
+
+	session->evlist->first_sample_time = first_sample_time;
+	session->evlist->last_sample_time = last_sample_time;
+	return 0;
+}
+
+static int process_mem_topology(struct feat_fd *ff,
+				void *data __maybe_unused)
+{
+	struct memory_node *nodes;
+	u64 version, i, nr, bsize;
+	int ret = -1;
+
+	if (do_read_u64(ff, &version))
+		return -1;
+
+	if (version != 1)
+		return -1;
+
+	if (do_read_u64(ff, &bsize))
+		return -1;
+
+	if (do_read_u64(ff, &nr))
+		return -1;
+
+	nodes = zalloc(sizeof(*nodes) * nr);
+	if (!nodes)
+		return -1;
+
+	for (i = 0; i < nr; i++) {
+		struct memory_node n;
+
+		#define _R(v)				\
+			if (do_read_u64(ff, &n.v))	\
+				goto out;		\
+
+		_R(node)
+		_R(size)
+
+		#undef _R
+
+		if (do_read_bitmap(ff, &n.set, &n.size))
+			goto out;
+
+		nodes[i] = n;
+	}
+
+	ff->ph->env.memory_bsize    = bsize;
+	ff->ph->env.memory_nodes    = nodes;
+	ff->ph->env.nr_memory_nodes = nr;
+	ret = 0;
+
+out:
+	if (ret)
+		free(nodes);
+	return ret;
+}
+
+struct feature_ops {
+	int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
+	void (*print)(struct feat_fd *ff, FILE *fp);
+	int (*process)(struct feat_fd *ff, void *data);
+	const char *name;
+	bool full_only;
+	bool synthesize;
+};
+
+#define FEAT_OPR(n, func, __full_only) \
+	[HEADER_##n] = {					\
+		.name	    = __stringify(n),			\
+		.write	    = write_##func,			\
+		.print	    = print_##func,			\
+		.full_only  = __full_only,			\
+		.process    = process_##func,			\
+		.synthesize = true				\
+	}
+
+#define FEAT_OPN(n, func, __full_only) \
+	[HEADER_##n] = {					\
+		.name	    = __stringify(n),			\
+		.write	    = write_##func,			\
+		.print	    = print_##func,			\
+		.full_only  = __full_only,			\
+		.process    = process_##func			\
+	}
+
+/* feature_ops not implemented: */
+#define print_tracing_data	NULL
+#define print_build_id		NULL
+
+#define process_branch_stack	NULL
+#define process_stat		NULL
+
+
+static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
+	FEAT_OPN(TRACING_DATA,	tracing_data,	false),
+	FEAT_OPN(BUILD_ID,	build_id,	false),
+	FEAT_OPR(HOSTNAME,	hostname,	false),
+	FEAT_OPR(OSRELEASE,	osrelease,	false),
+	FEAT_OPR(VERSION,	version,	false),
+	FEAT_OPR(ARCH,		arch,		false),
+	FEAT_OPR(NRCPUS,	nrcpus,		false),
+	FEAT_OPR(CPUDESC,	cpudesc,	false),
+	FEAT_OPR(CPUID,		cpuid,		false),
+	FEAT_OPR(TOTAL_MEM,	total_mem,	false),
+	FEAT_OPR(EVENT_DESC,	event_desc,	false),
+	FEAT_OPR(CMDLINE,	cmdline,	false),
+	FEAT_OPR(CPU_TOPOLOGY,	cpu_topology,	true),
+	FEAT_OPR(NUMA_TOPOLOGY,	numa_topology,	true),
+	FEAT_OPN(BRANCH_STACK,	branch_stack,	false),
+	FEAT_OPR(PMU_MAPPINGS,	pmu_mappings,	false),
+	FEAT_OPR(GROUP_DESC,	group_desc,	false),
+	FEAT_OPN(AUXTRACE,	auxtrace,	false),
+	FEAT_OPN(STAT,		stat,		false),
+	FEAT_OPN(CACHE,		cache,		true),
+	FEAT_OPR(SAMPLE_TIME,	sample_time,	false),
+	FEAT_OPR(MEM_TOPOLOGY,	mem_topology,	true),
+};
+
+struct header_print_data {
+	FILE *fp;
+	bool full; /* extended list of headers */
+};
+
+static int perf_file_section__fprintf_info(struct perf_file_section *section,
+					   struct perf_header *ph,
+					   int feat, int fd, void *data)
+{
+	struct header_print_data *hd = data;
+	struct feat_fd ff;
+
+	if (lseek(fd, section->offset, SEEK_SET) == (off_t)-1) {
+		pr_debug("Failed to lseek to %" PRIu64 " offset for feature "
+				"%d, continuing...\n", section->offset, feat);
+		return 0;
+	}
+	if (feat >= HEADER_LAST_FEATURE) {
+		pr_warning("unknown feature %d\n", feat);
+		return 0;
+	}
+	if (!feat_ops[feat].print)
+		return 0;
+
+	ff = (struct  feat_fd) {
+		.fd = fd,
+		.ph = ph,
+	};
+
+	if (!feat_ops[feat].full_only || hd->full)
+		feat_ops[feat].print(&ff, hd->fp);
+	else
+		fprintf(hd->fp, "# %s info available, use -I to display\n",
+			feat_ops[feat].name);
+
+	return 0;
+}
+
+int perf_header__fprintf_info(struct perf_session *session, FILE *fp, bool full)
+{
+	struct header_print_data hd;
+	struct perf_header *header = &session->header;
+	int fd = perf_data__fd(session->data);
+	struct stat st;
+	time_t stctime;
+	int ret, bit;
+
+	hd.fp = fp;
+	hd.full = full;
+
+	ret = fstat(fd, &st);
+	if (ret == -1)
+		return -1;
+
+	stctime = st.st_ctime;
+	fprintf(fp, "# captured on    : %s", ctime(&stctime));
+
+	fprintf(fp, "# header version : %u\n", header->version);
+	fprintf(fp, "# data offset    : %" PRIu64 "\n", header->data_offset);
+	fprintf(fp, "# data size      : %" PRIu64 "\n", header->data_size);
+	fprintf(fp, "# feat offset    : %" PRIu64 "\n", header->feat_offset);
+
+	perf_header__process_sections(header, fd, &hd,
+				      perf_file_section__fprintf_info);
+
+	if (session->data->is_pipe)
+		return 0;
+
+	fprintf(fp, "# missing features: ");
+	for_each_clear_bit(bit, header->adds_features, HEADER_LAST_FEATURE) {
+		if (bit)
+			fprintf(fp, "%s ", feat_ops[bit].name);
+	}
+
+	fprintf(fp, "\n");
+	return 0;
+}
+
+static int do_write_feat(struct feat_fd *ff, int type,
+			 struct perf_file_section **p,
+			 struct perf_evlist *evlist)
+{
+	int err;
+	int ret = 0;
+
+	if (perf_header__has_feat(ff->ph, type)) {
+		if (!feat_ops[type].write)
+			return -1;
+
+		if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+			return -1;
+
+		(*p)->offset = lseek(ff->fd, 0, SEEK_CUR);
+
+		err = feat_ops[type].write(ff, evlist);
+		if (err < 0) {
+			pr_debug("failed to write feature %s\n", feat_ops[type].name);
+
+			/* undo anything written */
+			lseek(ff->fd, (*p)->offset, SEEK_SET);
+
+			return -1;
+		}
+		(*p)->size = lseek(ff->fd, 0, SEEK_CUR) - (*p)->offset;
+		(*p)++;
+	}
+	return ret;
+}
+
+static int perf_header__adds_write(struct perf_header *header,
+				   struct perf_evlist *evlist, int fd)
+{
+	int nr_sections;
+	struct feat_fd ff;
+	struct perf_file_section *feat_sec, *p;
+	int sec_size;
+	u64 sec_start;
+	int feat;
+	int err;
+
+	ff = (struct feat_fd){
+		.fd  = fd,
+		.ph = header,
+	};
+
+	nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
+	if (!nr_sections)
+		return 0;
+
+	feat_sec = p = calloc(nr_sections, sizeof(*feat_sec));
+	if (feat_sec == NULL)
+		return -ENOMEM;
+
+	sec_size = sizeof(*feat_sec) * nr_sections;
+
+	sec_start = header->feat_offset;
+	lseek(fd, sec_start + sec_size, SEEK_SET);
+
+	for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) {
+		if (do_write_feat(&ff, feat, &p, evlist))
+			perf_header__clear_feat(header, feat);
+	}
+
+	lseek(fd, sec_start, SEEK_SET);
+	/*
+	 * may write more than needed due to dropped feature, but
+	 * this is okay, reader will skip the mising entries
+	 */
+	err = do_write(&ff, feat_sec, sec_size);
+	if (err < 0)
+		pr_debug("failed to write feature section\n");
+	free(feat_sec);
+	return err;
+}
+
+int perf_header__write_pipe(int fd)
+{
+	struct perf_pipe_file_header f_header;
+	struct feat_fd ff;
+	int err;
+
+	ff = (struct feat_fd){ .fd = fd };
+
+	f_header = (struct perf_pipe_file_header){
+		.magic	   = PERF_MAGIC,
+		.size	   = sizeof(f_header),
+	};
+
+	err = do_write(&ff, &f_header, sizeof(f_header));
+	if (err < 0) {
+		pr_debug("failed to write perf pipe header\n");
+		return err;
+	}
+
+	return 0;
+}
+
+int perf_session__write_header(struct perf_session *session,
+			       struct perf_evlist *evlist,
+			       int fd, bool at_exit)
+{
+	struct perf_file_header f_header;
+	struct perf_file_attr   f_attr;
+	struct perf_header *header = &session->header;
+	struct perf_evsel *evsel;
+	struct feat_fd ff;
+	u64 attr_offset;
+	int err;
+
+	ff = (struct feat_fd){ .fd = fd};
+	lseek(fd, sizeof(f_header), SEEK_SET);
+
+	evlist__for_each_entry(session->evlist, evsel) {
+		evsel->id_offset = lseek(fd, 0, SEEK_CUR);
+		err = do_write(&ff, evsel->id, evsel->ids * sizeof(u64));
+		if (err < 0) {
+			pr_debug("failed to write perf header\n");
+			return err;
+		}
+	}
+
+	attr_offset = lseek(ff.fd, 0, SEEK_CUR);
+
+	evlist__for_each_entry(evlist, evsel) {
+		f_attr = (struct perf_file_attr){
+			.attr = evsel->attr,
+			.ids  = {
+				.offset = evsel->id_offset,
+				.size   = evsel->ids * sizeof(u64),
+			}
+		};
+		err = do_write(&ff, &f_attr, sizeof(f_attr));
+		if (err < 0) {
+			pr_debug("failed to write perf header attribute\n");
+			return err;
+		}
+	}
+
+	if (!header->data_offset)
+		header->data_offset = lseek(fd, 0, SEEK_CUR);
+	header->feat_offset = header->data_offset + header->data_size;
+
+	if (at_exit) {
+		err = perf_header__adds_write(header, evlist, fd);
+		if (err < 0)
+			return err;
+	}
+
+	f_header = (struct perf_file_header){
+		.magic	   = PERF_MAGIC,
+		.size	   = sizeof(f_header),
+		.attr_size = sizeof(f_attr),
+		.attrs = {
+			.offset = attr_offset,
+			.size   = evlist->nr_entries * sizeof(f_attr),
+		},
+		.data = {
+			.offset = header->data_offset,
+			.size	= header->data_size,
+		},
+		/* event_types is ignored, store zeros */
+	};
+
+	memcpy(&f_header.adds_features, &header->adds_features, sizeof(header->adds_features));
+
+	lseek(fd, 0, SEEK_SET);
+	err = do_write(&ff, &f_header, sizeof(f_header));
+	if (err < 0) {
+		pr_debug("failed to write perf header\n");
+		return err;
+	}
+	lseek(fd, header->data_offset + header->data_size, SEEK_SET);
+
+	return 0;
+}
+
+static int perf_header__getbuffer64(struct perf_header *header,
+				    int fd, void *buf, size_t size)
+{
+	if (readn(fd, buf, size) <= 0)
+		return -1;
+
+	if (header->needs_swap)
+		mem_bswap_64(buf, size);
+
+	return 0;
+}
+
+int perf_header__process_sections(struct perf_header *header, int fd,
+				  void *data,
+				  int (*process)(struct perf_file_section *section,
+						 struct perf_header *ph,
+						 int feat, int fd, void *data))
+{
+	struct perf_file_section *feat_sec, *sec;
+	int nr_sections;
+	int sec_size;
+	int feat;
+	int err;
+
+	nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
+	if (!nr_sections)
+		return 0;
+
+	feat_sec = sec = calloc(nr_sections, sizeof(*feat_sec));
+	if (!feat_sec)
+		return -1;
+
+	sec_size = sizeof(*feat_sec) * nr_sections;
+
+	lseek(fd, header->feat_offset, SEEK_SET);
+
+	err = perf_header__getbuffer64(header, fd, feat_sec, sec_size);
+	if (err < 0)
+		goto out_free;
+
+	for_each_set_bit(feat, header->adds_features, HEADER_LAST_FEATURE) {
+		err = process(sec++, header, feat, fd, data);
+		if (err < 0)
+			goto out_free;
+	}
+	err = 0;
+out_free:
+	free(feat_sec);
+	return err;
+}
+
+static const int attr_file_abi_sizes[] = {
+	[0] = PERF_ATTR_SIZE_VER0,
+	[1] = PERF_ATTR_SIZE_VER1,
+	[2] = PERF_ATTR_SIZE_VER2,
+	[3] = PERF_ATTR_SIZE_VER3,
+	[4] = PERF_ATTR_SIZE_VER4,
+	0,
+};
+
+/*
+ * In the legacy file format, the magic number is not used to encode endianness.
+ * hdr_sz was used to encode endianness. But given that hdr_sz can vary based
+ * on ABI revisions, we need to try all combinations for all endianness to
+ * detect the endianness.
+ */
+static int try_all_file_abis(uint64_t hdr_sz, struct perf_header *ph)
+{
+	uint64_t ref_size, attr_size;
+	int i;
+
+	for (i = 0 ; attr_file_abi_sizes[i]; i++) {
+		ref_size = attr_file_abi_sizes[i]
+			 + sizeof(struct perf_file_section);
+		if (hdr_sz != ref_size) {
+			attr_size = bswap_64(hdr_sz);
+			if (attr_size != ref_size)
+				continue;
+
+			ph->needs_swap = true;
+		}
+		pr_debug("ABI%d perf.data file detected, need_swap=%d\n",
+			 i,
+			 ph->needs_swap);
+		return 0;
+	}
+	/* could not determine endianness */
+	return -1;
+}
+
+#define PERF_PIPE_HDR_VER0	16
+
+static const size_t attr_pipe_abi_sizes[] = {
+	[0] = PERF_PIPE_HDR_VER0,
+	0,
+};
+
+/*
+ * In the legacy pipe format, there is an implicit assumption that endiannesss
+ * between host recording the samples, and host parsing the samples is the
+ * same. This is not always the case given that the pipe output may always be
+ * redirected into a file and analyzed on a different machine with possibly a
+ * different endianness and perf_event ABI revsions in the perf tool itself.
+ */
+static int try_all_pipe_abis(uint64_t hdr_sz, struct perf_header *ph)
+{
+	u64 attr_size;
+	int i;
+
+	for (i = 0 ; attr_pipe_abi_sizes[i]; i++) {
+		if (hdr_sz != attr_pipe_abi_sizes[i]) {
+			attr_size = bswap_64(hdr_sz);
+			if (attr_size != hdr_sz)
+				continue;
+
+			ph->needs_swap = true;
+		}
+		pr_debug("Pipe ABI%d perf.data file detected\n", i);
+		return 0;
+	}
+	return -1;
+}
+
+bool is_perf_magic(u64 magic)
+{
+	if (!memcmp(&magic, __perf_magic1, sizeof(magic))
+		|| magic == __perf_magic2
+		|| magic == __perf_magic2_sw)
+		return true;
+
+	return false;
+}
+
+static int check_magic_endian(u64 magic, uint64_t hdr_sz,
+			      bool is_pipe, struct perf_header *ph)
+{
+	int ret;
+
+	/* check for legacy format */
+	ret = memcmp(&magic, __perf_magic1, sizeof(magic));
+	if (ret == 0) {
+		ph->version = PERF_HEADER_VERSION_1;
+		pr_debug("legacy perf.data format\n");
+		if (is_pipe)
+			return try_all_pipe_abis(hdr_sz, ph);
+
+		return try_all_file_abis(hdr_sz, ph);
+	}
+	/*
+	 * the new magic number serves two purposes:
+	 * - unique number to identify actual perf.data files
+	 * - encode endianness of file
+	 */
+	ph->version = PERF_HEADER_VERSION_2;
+
+	/* check magic number with one endianness */
+	if (magic == __perf_magic2)
+		return 0;
+
+	/* check magic number with opposite endianness */
+	if (magic != __perf_magic2_sw)
+		return -1;
+
+	ph->needs_swap = true;
+
+	return 0;
+}
+
+int perf_file_header__read(struct perf_file_header *header,
+			   struct perf_header *ph, int fd)
+{
+	ssize_t ret;
+
+	lseek(fd, 0, SEEK_SET);
+
+	ret = readn(fd, header, sizeof(*header));
+	if (ret <= 0)
+		return -1;
+
+	if (check_magic_endian(header->magic,
+			       header->attr_size, false, ph) < 0) {
+		pr_debug("magic/endian check failed\n");
+		return -1;
+	}
+
+	if (ph->needs_swap) {
+		mem_bswap_64(header, offsetof(struct perf_file_header,
+			     adds_features));
+	}
+
+	if (header->size != sizeof(*header)) {
+		/* Support the previous format */
+		if (header->size == offsetof(typeof(*header), adds_features))
+			bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
+		else
+			return -1;
+	} else if (ph->needs_swap) {
+		/*
+		 * feature bitmap is declared as an array of unsigned longs --
+		 * not good since its size can differ between the host that
+		 * generated the data file and the host analyzing the file.
+		 *
+		 * We need to handle endianness, but we don't know the size of
+		 * the unsigned long where the file was generated. Take a best
+		 * guess at determining it: try 64-bit swap first (ie., file
+		 * created on a 64-bit host), and check if the hostname feature
+		 * bit is set (this feature bit is forced on as of fbe96f2).
+		 * If the bit is not, undo the 64-bit swap and try a 32-bit
+		 * swap. If the hostname bit is still not set (e.g., older data
+		 * file), punt and fallback to the original behavior --
+		 * clearing all feature bits and setting buildid.
+		 */
+		mem_bswap_64(&header->adds_features,
+			    BITS_TO_U64(HEADER_FEAT_BITS));
+
+		if (!test_bit(HEADER_HOSTNAME, header->adds_features)) {
+			/* unswap as u64 */
+			mem_bswap_64(&header->adds_features,
+				    BITS_TO_U64(HEADER_FEAT_BITS));
+
+			/* unswap as u32 */
+			mem_bswap_32(&header->adds_features,
+				    BITS_TO_U32(HEADER_FEAT_BITS));
+		}
+
+		if (!test_bit(HEADER_HOSTNAME, header->adds_features)) {
+			bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
+			set_bit(HEADER_BUILD_ID, header->adds_features);
+		}
+	}
+
+	memcpy(&ph->adds_features, &header->adds_features,
+	       sizeof(ph->adds_features));
+
+	ph->data_offset  = header->data.offset;
+	ph->data_size	 = header->data.size;
+	ph->feat_offset  = header->data.offset + header->data.size;
+	return 0;
+}
+
+static int perf_file_section__process(struct perf_file_section *section,
+				      struct perf_header *ph,
+				      int feat, int fd, void *data)
+{
+	struct feat_fd fdd = {
+		.fd	= fd,
+		.ph	= ph,
+		.size	= section->size,
+		.offset	= section->offset,
+	};
+
+	if (lseek(fd, section->offset, SEEK_SET) == (off_t)-1) {
+		pr_debug("Failed to lseek to %" PRIu64 " offset for feature "
+			  "%d, continuing...\n", section->offset, feat);
+		return 0;
+	}
+
+	if (feat >= HEADER_LAST_FEATURE) {
+		pr_debug("unknown feature %d, continuing...\n", feat);
+		return 0;
+	}
+
+	if (!feat_ops[feat].process)
+		return 0;
+
+	return feat_ops[feat].process(&fdd, data);
+}
+
+static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
+				       struct perf_header *ph, int fd,
+				       bool repipe)
+{
+	struct feat_fd ff = {
+		.fd = STDOUT_FILENO,
+		.ph = ph,
+	};
+	ssize_t ret;
+
+	ret = readn(fd, header, sizeof(*header));
+	if (ret <= 0)
+		return -1;
+
+	if (check_magic_endian(header->magic, header->size, true, ph) < 0) {
+		pr_debug("endian/magic failed\n");
+		return -1;
+	}
+
+	if (ph->needs_swap)
+		header->size = bswap_64(header->size);
+
+	if (repipe && do_write(&ff, header, sizeof(*header)) < 0)
+		return -1;
+
+	return 0;
+}
+
+static int perf_header__read_pipe(struct perf_session *session)
+{
+	struct perf_header *header = &session->header;
+	struct perf_pipe_file_header f_header;
+
+	if (perf_file_header__read_pipe(&f_header, header,
+					perf_data__fd(session->data),
+					session->repipe) < 0) {
+		pr_debug("incompatible file format\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int read_attr(int fd, struct perf_header *ph,
+		     struct perf_file_attr *f_attr)
+{
+	struct perf_event_attr *attr = &f_attr->attr;
+	size_t sz, left;
+	size_t our_sz = sizeof(f_attr->attr);
+	ssize_t ret;
+
+	memset(f_attr, 0, sizeof(*f_attr));
+
+	/* read minimal guaranteed structure */
+	ret = readn(fd, attr, PERF_ATTR_SIZE_VER0);
+	if (ret <= 0) {
+		pr_debug("cannot read %d bytes of header attr\n",
+			 PERF_ATTR_SIZE_VER0);
+		return -1;
+	}
+
+	/* on file perf_event_attr size */
+	sz = attr->size;
+
+	if (ph->needs_swap)
+		sz = bswap_32(sz);
+
+	if (sz == 0) {
+		/* assume ABI0 */
+		sz =  PERF_ATTR_SIZE_VER0;
+	} else if (sz > our_sz) {
+		pr_debug("file uses a more recent and unsupported ABI"
+			 " (%zu bytes extra)\n", sz - our_sz);
+		return -1;
+	}
+	/* what we have not yet read and that we know about */
+	left = sz - PERF_ATTR_SIZE_VER0;
+	if (left) {
+		void *ptr = attr;
+		ptr += PERF_ATTR_SIZE_VER0;
+
+		ret = readn(fd, ptr, left);
+	}
+	/* read perf_file_section, ids are read in caller */
+	ret = readn(fd, &f_attr->ids, sizeof(f_attr->ids));
+
+	return ret <= 0 ? -1 : 0;
+}
+
+static int perf_evsel__prepare_tracepoint_event(struct perf_evsel *evsel,
+						struct tep_handle *pevent)
+{
+	struct event_format *event;
+	char bf[128];
+
+	/* already prepared */
+	if (evsel->tp_format)
+		return 0;
+
+	if (pevent == NULL) {
+		pr_debug("broken or missing trace data\n");
+		return -1;
+	}
+
+	event = tep_find_event(pevent, evsel->attr.config);
+	if (event == NULL) {
+		pr_debug("cannot find event format for %d\n", (int)evsel->attr.config);
+		return -1;
+	}
+
+	if (!evsel->name) {
+		snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name);
+		evsel->name = strdup(bf);
+		if (evsel->name == NULL)
+			return -1;
+	}
+
+	evsel->tp_format = event;
+	return 0;
+}
+
+static int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
+						  struct tep_handle *pevent)
+{
+	struct perf_evsel *pos;
+
+	evlist__for_each_entry(evlist, pos) {
+		if (pos->attr.type == PERF_TYPE_TRACEPOINT &&
+		    perf_evsel__prepare_tracepoint_event(pos, pevent))
+			return -1;
+	}
+
+	return 0;
+}
+
+int perf_session__read_header(struct perf_session *session)
+{
+	struct perf_data *data = session->data;
+	struct perf_header *header = &session->header;
+	struct perf_file_header	f_header;
+	struct perf_file_attr	f_attr;
+	u64			f_id;
+	int nr_attrs, nr_ids, i, j;
+	int fd = perf_data__fd(data);
+
+	session->evlist = perf_evlist__new();
+	if (session->evlist == NULL)
+		return -ENOMEM;
+
+	session->evlist->env = &header->env;
+	session->machines.host.env = &header->env;
+	if (perf_data__is_pipe(data))
+		return perf_header__read_pipe(session);
+
+	if (perf_file_header__read(&f_header, header, fd) < 0)
+		return -EINVAL;
+
+	/*
+	 * Sanity check that perf.data was written cleanly; data size is
+	 * initialized to 0 and updated only if the on_exit function is run.
+	 * If data size is still 0 then the file contains only partial
+	 * information.  Just warn user and process it as much as it can.
+	 */
+	if (f_header.data.size == 0) {
+		pr_warning("WARNING: The %s file's data size field is 0 which is unexpected.\n"
+			   "Was the 'perf record' command properly terminated?\n",
+			   data->file.path);
+	}
+
+	if (f_header.attr_size == 0) {
+		pr_err("ERROR: The %s file's attr size field is 0 which is unexpected.\n"
+		       "Was the 'perf record' command properly terminated?\n",
+		       data->file.path);
+		return -EINVAL;
+	}
+
+	nr_attrs = f_header.attrs.size / f_header.attr_size;
+	lseek(fd, f_header.attrs.offset, SEEK_SET);
+
+	for (i = 0; i < nr_attrs; i++) {
+		struct perf_evsel *evsel;
+		off_t tmp;
+
+		if (read_attr(fd, header, &f_attr) < 0)
+			goto out_errno;
+
+		if (header->needs_swap) {
+			f_attr.ids.size   = bswap_64(f_attr.ids.size);
+			f_attr.ids.offset = bswap_64(f_attr.ids.offset);
+			perf_event__attr_swap(&f_attr.attr);
+		}
+
+		tmp = lseek(fd, 0, SEEK_CUR);
+		evsel = perf_evsel__new(&f_attr.attr);
+
+		if (evsel == NULL)
+			goto out_delete_evlist;
+
+		evsel->needs_swap = header->needs_swap;
+		/*
+		 * Do it before so that if perf_evsel__alloc_id fails, this
+		 * entry gets purged too at perf_evlist__delete().
+		 */
+		perf_evlist__add(session->evlist, evsel);
+
+		nr_ids = f_attr.ids.size / sizeof(u64);
+		/*
+		 * We don't have the cpu and thread maps on the header, so
+		 * for allocating the perf_sample_id table we fake 1 cpu and
+		 * hattr->ids threads.
+		 */
+		if (perf_evsel__alloc_id(evsel, 1, nr_ids))
+			goto out_delete_evlist;
+
+		lseek(fd, f_attr.ids.offset, SEEK_SET);
+
+		for (j = 0; j < nr_ids; j++) {
+			if (perf_header__getbuffer64(header, fd, &f_id, sizeof(f_id)))
+				goto out_errno;
+
+			perf_evlist__id_add(session->evlist, evsel, 0, j, f_id);
+		}
+
+		lseek(fd, tmp, SEEK_SET);
+	}
+
+	perf_header__process_sections(header, fd, &session->tevent,
+				      perf_file_section__process);
+
+	if (perf_evlist__prepare_tracepoint_events(session->evlist,
+						   session->tevent.pevent))
+		goto out_delete_evlist;
+
+	return 0;
+out_errno:
+	return -errno;
+
+out_delete_evlist:
+	perf_evlist__delete(session->evlist);
+	session->evlist = NULL;
+	return -ENOMEM;
+}
+
+int perf_event__synthesize_attr(struct perf_tool *tool,
+				struct perf_event_attr *attr, u32 ids, u64 *id,
+				perf_event__handler_t process)
+{
+	union perf_event *ev;
+	size_t size;
+	int err;
+
+	size = sizeof(struct perf_event_attr);
+	size = PERF_ALIGN(size, sizeof(u64));
+	size += sizeof(struct perf_event_header);
+	size += ids * sizeof(u64);
+
+	ev = zalloc(size);
+
+	if (ev == NULL)
+		return -ENOMEM;
+
+	ev->attr.attr = *attr;
+	memcpy(ev->attr.id, id, ids * sizeof(u64));
+
+	ev->attr.header.type = PERF_RECORD_HEADER_ATTR;
+	ev->attr.header.size = (u16)size;
+
+	if (ev->attr.header.size == size)
+		err = process(tool, ev, NULL, NULL);
+	else
+		err = -E2BIG;
+
+	free(ev);
+
+	return err;
+}
+
+int perf_event__synthesize_features(struct perf_tool *tool,
+				    struct perf_session *session,
+				    struct perf_evlist *evlist,
+				    perf_event__handler_t process)
+{
+	struct perf_header *header = &session->header;
+	struct feat_fd ff;
+	struct feature_event *fe;
+	size_t sz, sz_hdr;
+	int feat, ret;
+
+	sz_hdr = sizeof(fe->header);
+	sz = sizeof(union perf_event);
+	/* get a nice alignment */
+	sz = PERF_ALIGN(sz, page_size);
+
+	memset(&ff, 0, sizeof(ff));
+
+	ff.buf = malloc(sz);
+	if (!ff.buf)
+		return -ENOMEM;
+
+	ff.size = sz - sz_hdr;
+
+	for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) {
+		if (!feat_ops[feat].synthesize) {
+			pr_debug("No record header feature for header :%d\n", feat);
+			continue;
+		}
+
+		ff.offset = sizeof(*fe);
+
+		ret = feat_ops[feat].write(&ff, evlist);
+		if (ret || ff.offset <= (ssize_t)sizeof(*fe)) {
+			pr_debug("Error writing feature\n");
+			continue;
+		}
+		/* ff.buf may have changed due to realloc in do_write() */
+		fe = ff.buf;
+		memset(fe, 0, sizeof(*fe));
+
+		fe->feat_id = feat;
+		fe->header.type = PERF_RECORD_HEADER_FEATURE;
+		fe->header.size = ff.offset;
+
+		ret = process(tool, ff.buf, NULL, NULL);
+		if (ret) {
+			free(ff.buf);
+			return ret;
+		}
+	}
+
+	/* Send HEADER_LAST_FEATURE mark. */
+	fe = ff.buf;
+	fe->feat_id     = HEADER_LAST_FEATURE;
+	fe->header.type = PERF_RECORD_HEADER_FEATURE;
+	fe->header.size = sizeof(*fe);
+
+	ret = process(tool, ff.buf, NULL, NULL);
+
+	free(ff.buf);
+	return ret;
+}
+
+int perf_event__process_feature(struct perf_tool *tool,
+				union perf_event *event,
+				struct perf_session *session __maybe_unused)
+{
+	struct feat_fd ff = { .fd = 0 };
+	struct feature_event *fe = (struct feature_event *)event;
+	int type = fe->header.type;
+	u64 feat = fe->feat_id;
+
+	if (type < 0 || type >= PERF_RECORD_HEADER_MAX) {
+		pr_warning("invalid record type %d in pipe-mode\n", type);
+		return 0;
+	}
+	if (feat == HEADER_RESERVED || feat >= HEADER_LAST_FEATURE) {
+		pr_warning("invalid record type %d in pipe-mode\n", type);
+		return -1;
+	}
+
+	if (!feat_ops[feat].process)
+		return 0;
+
+	ff.buf  = (void *)fe->data;
+	ff.size = event->header.size - sizeof(*fe);
+	ff.ph = &session->header;
+
+	if (feat_ops[feat].process(&ff, NULL))
+		return -1;
+
+	if (!feat_ops[feat].print || !tool->show_feat_hdr)
+		return 0;
+
+	if (!feat_ops[feat].full_only ||
+	    tool->show_feat_hdr >= SHOW_FEAT_HEADER_FULL_INFO) {
+		feat_ops[feat].print(&ff, stdout);
+	} else {
+		fprintf(stdout, "# %s info available, use -I to display\n",
+			feat_ops[feat].name);
+	}
+
+	return 0;
+}
+
+static struct event_update_event *
+event_update_event__new(size_t size, u64 type, u64 id)
+{
+	struct event_update_event *ev;
+
+	size += sizeof(*ev);
+	size  = PERF_ALIGN(size, sizeof(u64));
+
+	ev = zalloc(size);
+	if (ev) {
+		ev->header.type = PERF_RECORD_EVENT_UPDATE;
+		ev->header.size = (u16)size;
+		ev->type = type;
+		ev->id = id;
+	}
+	return ev;
+}
+
+int
+perf_event__synthesize_event_update_unit(struct perf_tool *tool,
+					 struct perf_evsel *evsel,
+					 perf_event__handler_t process)
+{
+	struct event_update_event *ev;
+	size_t size = strlen(evsel->unit);
+	int err;
+
+	ev = event_update_event__new(size + 1, PERF_EVENT_UPDATE__UNIT, evsel->id[0]);
+	if (ev == NULL)
+		return -ENOMEM;
+
+	strlcpy(ev->data, evsel->unit, size + 1);
+	err = process(tool, (union perf_event *)ev, NULL, NULL);
+	free(ev);
+	return err;
+}
+
+int
+perf_event__synthesize_event_update_scale(struct perf_tool *tool,
+					  struct perf_evsel *evsel,
+					  perf_event__handler_t process)
+{
+	struct event_update_event *ev;
+	struct event_update_event_scale *ev_data;
+	int err;
+
+	ev = event_update_event__new(sizeof(*ev_data), PERF_EVENT_UPDATE__SCALE, evsel->id[0]);
+	if (ev == NULL)
+		return -ENOMEM;
+
+	ev_data = (struct event_update_event_scale *) ev->data;
+	ev_data->scale = evsel->scale;
+	err = process(tool, (union perf_event*) ev, NULL, NULL);
+	free(ev);
+	return err;
+}
+
+int
+perf_event__synthesize_event_update_name(struct perf_tool *tool,
+					 struct perf_evsel *evsel,
+					 perf_event__handler_t process)
+{
+	struct event_update_event *ev;
+	size_t len = strlen(evsel->name);
+	int err;
+
+	ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
+	if (ev == NULL)
+		return -ENOMEM;
+
+	strlcpy(ev->data, evsel->name, len + 1);
+	err = process(tool, (union perf_event*) ev, NULL, NULL);
+	free(ev);
+	return err;
+}
+
+int
+perf_event__synthesize_event_update_cpus(struct perf_tool *tool,
+					struct perf_evsel *evsel,
+					perf_event__handler_t process)
+{
+	size_t size = sizeof(struct event_update_event);
+	struct event_update_event *ev;
+	int max, err;
+	u16 type;
+
+	if (!evsel->own_cpus)
+		return 0;
+
+	ev = cpu_map_data__alloc(evsel->own_cpus, &size, &type, &max);
+	if (!ev)
+		return -ENOMEM;
+
+	ev->header.type = PERF_RECORD_EVENT_UPDATE;
+	ev->header.size = (u16)size;
+	ev->type = PERF_EVENT_UPDATE__CPUS;
+	ev->id   = evsel->id[0];
+
+	cpu_map_data__synthesize((struct cpu_map_data *) ev->data,
+				 evsel->own_cpus,
+				 type, max);
+
+	err = process(tool, (union perf_event*) ev, NULL, NULL);
+	free(ev);
+	return err;
+}
+
+size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp)
+{
+	struct event_update_event *ev = &event->event_update;
+	struct event_update_event_scale *ev_scale;
+	struct event_update_event_cpus *ev_cpus;
+	struct cpu_map *map;
+	size_t ret;
+
+	ret = fprintf(fp, "\n... id:    %" PRIu64 "\n", ev->id);
+
+	switch (ev->type) {
+	case PERF_EVENT_UPDATE__SCALE:
+		ev_scale = (struct event_update_event_scale *) ev->data;
+		ret += fprintf(fp, "... scale: %f\n", ev_scale->scale);
+		break;
+	case PERF_EVENT_UPDATE__UNIT:
+		ret += fprintf(fp, "... unit:  %s\n", ev->data);
+		break;
+	case PERF_EVENT_UPDATE__NAME:
+		ret += fprintf(fp, "... name:  %s\n", ev->data);
+		break;
+	case PERF_EVENT_UPDATE__CPUS:
+		ev_cpus = (struct event_update_event_cpus *) ev->data;
+		ret += fprintf(fp, "... ");
+
+		map = cpu_map__new_data(&ev_cpus->cpus);
+		if (map)
+			ret += cpu_map__fprintf(map, fp);
+		else
+			ret += fprintf(fp, "failed to get cpus\n");
+		break;
+	default:
+		ret += fprintf(fp, "... unknown type\n");
+		break;
+	}
+
+	return ret;
+}
+
+int perf_event__synthesize_attrs(struct perf_tool *tool,
+				   struct perf_session *session,
+				   perf_event__handler_t process)
+{
+	struct perf_evsel *evsel;
+	int err = 0;
+
+	evlist__for_each_entry(session->evlist, evsel) {
+		err = perf_event__synthesize_attr(tool, &evsel->attr, evsel->ids,
+						  evsel->id, process);
+		if (err) {
+			pr_debug("failed to create perf header attribute\n");
+			return err;
+		}
+	}
+
+	return err;
+}
+
+static bool has_unit(struct perf_evsel *counter)
+{
+	return counter->unit && *counter->unit;
+}
+
+static bool has_scale(struct perf_evsel *counter)
+{
+	return counter->scale != 1;
+}
+
+int perf_event__synthesize_extra_attr(struct perf_tool *tool,
+				      struct perf_evlist *evsel_list,
+				      perf_event__handler_t process,
+				      bool is_pipe)
+{
+	struct perf_evsel *counter;
+	int err;
+
+	/*
+	 * Synthesize other events stuff not carried within
+	 * attr event - unit, scale, name
+	 */
+	evlist__for_each_entry(evsel_list, counter) {
+		if (!counter->supported)
+			continue;
+
+		/*
+		 * Synthesize unit and scale only if it's defined.
+		 */
+		if (has_unit(counter)) {
+			err = perf_event__synthesize_event_update_unit(tool, counter, process);
+			if (err < 0) {
+				pr_err("Couldn't synthesize evsel unit.\n");
+				return err;
+			}
+		}
+
+		if (has_scale(counter)) {
+			err = perf_event__synthesize_event_update_scale(tool, counter, process);
+			if (err < 0) {
+				pr_err("Couldn't synthesize evsel counter.\n");
+				return err;
+			}
+		}
+
+		if (counter->own_cpus) {
+			err = perf_event__synthesize_event_update_cpus(tool, counter, process);
+			if (err < 0) {
+				pr_err("Couldn't synthesize evsel cpus.\n");
+				return err;
+			}
+		}
+
+		/*
+		 * Name is needed only for pipe output,
+		 * perf.data carries event names.
+		 */
+		if (is_pipe) {
+			err = perf_event__synthesize_event_update_name(tool, counter, process);
+			if (err < 0) {
+				pr_err("Couldn't synthesize evsel name.\n");
+				return err;
+			}
+		}
+	}
+	return 0;
+}
+
+int perf_event__process_attr(struct perf_tool *tool __maybe_unused,
+			     union perf_event *event,
+			     struct perf_evlist **pevlist)
+{
+	u32 i, ids, n_ids;
+	struct perf_evsel *evsel;
+	struct perf_evlist *evlist = *pevlist;
+
+	if (evlist == NULL) {
+		*pevlist = evlist = perf_evlist__new();
+		if (evlist == NULL)
+			return -ENOMEM;
+	}
+
+	evsel = perf_evsel__new(&event->attr.attr);
+	if (evsel == NULL)
+		return -ENOMEM;
+
+	perf_evlist__add(evlist, evsel);
+
+	ids = event->header.size;
+	ids -= (void *)&event->attr.id - (void *)event;
+	n_ids = ids / sizeof(u64);
+	/*
+	 * We don't have the cpu and thread maps on the header, so
+	 * for allocating the perf_sample_id table we fake 1 cpu and
+	 * hattr->ids threads.
+	 */
+	if (perf_evsel__alloc_id(evsel, 1, n_ids))
+		return -ENOMEM;
+
+	for (i = 0; i < n_ids; i++) {
+		perf_evlist__id_add(evlist, evsel, 0, i, event->attr.id[i]);
+	}
+
+	return 0;
+}
+
+int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,
+				     union perf_event *event,
+				     struct perf_evlist **pevlist)
+{
+	struct event_update_event *ev = &event->event_update;
+	struct event_update_event_scale *ev_scale;
+	struct event_update_event_cpus *ev_cpus;
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	struct cpu_map *map;
+
+	if (!pevlist || *pevlist == NULL)
+		return -EINVAL;
+
+	evlist = *pevlist;
+
+	evsel = perf_evlist__id2evsel(evlist, ev->id);
+	if (evsel == NULL)
+		return -EINVAL;
+
+	switch (ev->type) {
+	case PERF_EVENT_UPDATE__UNIT:
+		evsel->unit = strdup(ev->data);
+		break;
+	case PERF_EVENT_UPDATE__NAME:
+		evsel->name = strdup(ev->data);
+		break;
+	case PERF_EVENT_UPDATE__SCALE:
+		ev_scale = (struct event_update_event_scale *) ev->data;
+		evsel->scale = ev_scale->scale;
+		break;
+	case PERF_EVENT_UPDATE__CPUS:
+		ev_cpus = (struct event_update_event_cpus *) ev->data;
+
+		map = cpu_map__new_data(&ev_cpus->cpus);
+		if (map)
+			evsel->own_cpus = map;
+		else
+			pr_err("failed to get event_update cpus\n");
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+int perf_event__synthesize_tracing_data(struct perf_tool *tool, int fd,
+					struct perf_evlist *evlist,
+					perf_event__handler_t process)
+{
+	union perf_event ev;
+	struct tracing_data *tdata;
+	ssize_t size = 0, aligned_size = 0, padding;
+	struct feat_fd ff;
+	int err __maybe_unused = 0;
+
+	/*
+	 * We are going to store the size of the data followed
+	 * by the data contents. Since the fd descriptor is a pipe,
+	 * we cannot seek back to store the size of the data once
+	 * we know it. Instead we:
+	 *
+	 * - write the tracing data to the temp file
+	 * - get/write the data size to pipe
+	 * - write the tracing data from the temp file
+	 *   to the pipe
+	 */
+	tdata = tracing_data_get(&evlist->entries, fd, true);
+	if (!tdata)
+		return -1;
+
+	memset(&ev, 0, sizeof(ev));
+
+	ev.tracing_data.header.type = PERF_RECORD_HEADER_TRACING_DATA;
+	size = tdata->size;
+	aligned_size = PERF_ALIGN(size, sizeof(u64));
+	padding = aligned_size - size;
+	ev.tracing_data.header.size = sizeof(ev.tracing_data);
+	ev.tracing_data.size = aligned_size;
+
+	process(tool, &ev, NULL, NULL);
+
+	/*
+	 * The put function will copy all the tracing data
+	 * stored in temp file to the pipe.
+	 */
+	tracing_data_put(tdata);
+
+	ff = (struct feat_fd){ .fd = fd };
+	if (write_padded(&ff, NULL, 0, padding))
+		return -1;
+
+	return aligned_size;
+}
+
+int perf_event__process_tracing_data(struct perf_tool *tool __maybe_unused,
+				     union perf_event *event,
+				     struct perf_session *session)
+{
+	ssize_t size_read, padding, size = event->tracing_data.size;
+	int fd = perf_data__fd(session->data);
+	off_t offset = lseek(fd, 0, SEEK_CUR);
+	char buf[BUFSIZ];
+
+	/* setup for reading amidst mmap */
+	lseek(fd, offset + sizeof(struct tracing_data_event),
+	      SEEK_SET);
+
+	size_read = trace_report(fd, &session->tevent,
+				 session->repipe);
+	padding = PERF_ALIGN(size_read, sizeof(u64)) - size_read;
+
+	if (readn(fd, buf, padding) < 0) {
+		pr_err("%s: reading input file", __func__);
+		return -1;
+	}
+	if (session->repipe) {
+		int retw = write(STDOUT_FILENO, buf, padding);
+		if (retw <= 0 || retw != padding) {
+			pr_err("%s: repiping tracing data padding", __func__);
+			return -1;
+		}
+	}
+
+	if (size_read + padding != size) {
+		pr_err("%s: tracing data size mismatch", __func__);
+		return -1;
+	}
+
+	perf_evlist__prepare_tracepoint_events(session->evlist,
+					       session->tevent.pevent);
+
+	return size_read + padding;
+}
+
+int perf_event__synthesize_build_id(struct perf_tool *tool,
+				    struct dso *pos, u16 misc,
+				    perf_event__handler_t process,
+				    struct machine *machine)
+{
+	union perf_event ev;
+	size_t len;
+	int err = 0;
+
+	if (!pos->hit)
+		return err;
+
+	memset(&ev, 0, sizeof(ev));
+
+	len = pos->long_name_len + 1;
+	len = PERF_ALIGN(len, NAME_ALIGN);
+	memcpy(&ev.build_id.build_id, pos->build_id, sizeof(pos->build_id));
+	ev.build_id.header.type = PERF_RECORD_HEADER_BUILD_ID;
+	ev.build_id.header.misc = misc;
+	ev.build_id.pid = machine->pid;
+	ev.build_id.header.size = sizeof(ev.build_id) + len;
+	memcpy(&ev.build_id.filename, pos->long_name, pos->long_name_len);
+
+	err = process(tool, &ev, NULL, machine);
+
+	return err;
+}
+
+int perf_event__process_build_id(struct perf_tool *tool __maybe_unused,
+				 union perf_event *event,
+				 struct perf_session *session)
+{
+	__event_process_build_id(&event->build_id,
+				 event->build_id.filename,
+				 session);
+	return 0;
+}