linux/tools/perf/arch/x86/util/event.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/string.h>
#include <linux/zalloc.h>
#include <stdlib.h>

#include "../../../util/event.h"
#include "../../../util/synthetic-events.h"
#include "../../../util/machine.h"
#include "../../../util/tool.h"
#include "../../../util/map.h"
#include "../../../util/debug.h"
#include "util/sample.h"

#if defined(__x86_64__)

struct perf_event__synthesize_extra_kmaps_cb_args {
	const struct perf_tool *tool;
	perf_event__handler_t process;
	struct machine *machine;
	union perf_event *event;
};

static int perf_event__synthesize_extra_kmaps_cb(struct map *map, void *data)
{
	struct perf_event__synthesize_extra_kmaps_cb_args *args = data;
	union perf_event *event = args->event;
	struct kmap *kmap;
	size_t size;

	if (!__map__is_extra_kernel_map(map))
		return 0;

	kmap = map__kmap(map);

	size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
		      PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
		      args->machine->id_hdr_size;

	memset(event, 0, size);

	event->mmap.header.type = PERF_RECORD_MMAP;

	/*
	 * kernel uses 0 for user space maps, see kernel/perf_event.c
	 * __perf_event_mmap
	 */
	if (machine__is_host(args->machine))
		event->header.misc = PERF_RECORD_MISC_KERNEL;
	else
		event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;

	event->mmap.header.size = size;

	event->mmap.start = map__start(map);
	event->mmap.len   = map__size(map);
	event->mmap.pgoff = map__pgoff(map);
	event->mmap.pid   = args->machine->pid;

	strlcpy(event->mmap.filename, kmap->name, PATH_MAX);

	if (perf_tool__process_synth_event(args->tool, event, args->machine, args->process) != 0)
		return -1;

	return 0;
}

int perf_event__synthesize_extra_kmaps(const struct perf_tool *tool,
				       perf_event__handler_t process,
				       struct machine *machine)
{
	int rc;
	struct maps *kmaps = machine__kernel_maps(machine);
	struct perf_event__synthesize_extra_kmaps_cb_args args = {
		.tool = tool,
		.process = process,
		.machine = machine,
		.event = zalloc(sizeof(args.event->mmap) + machine->id_hdr_size),
	};

	if (!args.event) {
		pr_debug("Not enough memory synthesizing mmap event "
			 "for extra kernel maps\n");
		return -1;
	}

	rc = maps__for_each_map(kmaps, perf_event__synthesize_extra_kmaps_cb, &args);

	free(args.event);
	return rc;
}

#endif