/* SPDX-License-Identifier: GPL-2.0 */ #include "perf-sys.h"#include "util/cloexec.h"#include "util/evlist.h"#include "util/evsel.h"#include "util/parse-events.h"#include "util/perf_api_probe.h"#include <perf/cpumap.h>#include <errno.h> typedef void (*setup_probe_fn_t)(struct evsel *evsel); static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str){	struct evlist *evlist;	struct evsel *evsel;	unsigned long flags = perf_event_open_cloexec_flag();	int err = -EAGAIN, fd;	static pid_t pid = -1; 	evlist = evlist__new();	if (!evlist)		return -ENOMEM; 	if (parse_events(evlist, str, NULL))		goto out_delete; 	evsel = evlist__first(evlist); 	while (1) {		fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1, flags);		if (fd < 0) {			if (pid == -1 && errno == EACCES) {				pid = 0;				continue;			}			goto out_delete;		}		break;	}	close(fd); 	fn(evsel); 	fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1, flags);	if (fd < 0) {		if (errno == EINVAL)			err = -EINVAL;		goto out_delete;	}	close(fd);	err = 0; out_delete:	evlist__delete(evlist);	return err;} static bool perf_probe_api(setup_probe_fn_t fn){	const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};	struct perf_cpu_map *cpus;	int cpu, ret, i = 0; 	cpus = perf_cpu_map__new(NULL);	if (!cpus)		return false;	cpu = cpus->map[0];	perf_cpu_map__put(cpus); 	do {		ret = perf_do_probe_api(fn, cpu, try[i++]);		if (!ret)			return true;	} while (ret == -EAGAIN && try[i]); 	return false;} static void perf_probe_sample_identifier(struct evsel *evsel){	evsel->core.attr.sample_type |= PERF_SAMPLE_IDENTIFIER;} static void perf_probe_comm_exec(struct evsel *evsel){	evsel->core.attr.comm_exec = 1;} static void perf_probe_context_switch(struct evsel *evsel){	evsel->core.attr.context_switch = 1;} static void perf_probe_text_poke(struct evsel *evsel){	evsel->core.attr.text_poke = 1;} bool perf_can_sample_identifier(void){	return perf_probe_api(perf_probe_sample_identifier);} bool perf_can_comm_exec(void){	return perf_probe_api(perf_probe_comm_exec);} bool perf_can_record_switch_events(void){	return perf_probe_api(perf_probe_context_switch);} bool perf_can_record_text_poke_events(void){	return perf_probe_api(perf_probe_text_poke);} bool perf_can_record_cpu_wide(void){	struct perf_event_attr attr = {		.type = PERF_TYPE_SOFTWARE,		.config = PERF_COUNT_SW_CPU_CLOCK,		.exclude_kernel = 1,	};	struct perf_cpu_map *cpus;	int cpu, fd; 	cpus = perf_cpu_map__new(NULL);	if (!cpus)		return false;	cpu = cpus->map[0];	perf_cpu_map__put(cpus); 	fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);	if (fd < 0)		return false;	close(fd); 	return true;} /* * Architectures are expected to know if AUX area sampling is supported by the * hardware. Here we check for kernel support. */bool perf_can_aux_sample(void){	struct perf_event_attr attr = {		.size = sizeof(struct perf_event_attr),		.exclude_kernel = 1,		/*		 * Non-zero value causes the kernel to calculate the effective		 * attribute size up to that byte.		 */		.aux_sample_size = 1,	};	int fd; 	fd = sys_perf_event_open(&attr, -1, 0, -1, 0);	/*	 * If the kernel attribute is big enough to contain aux_sample_size	 * then we assume that it is supported. We are relying on the kernel to	 * validate the attribute size before anything else that could be wrong.	 */	if (fd < 0 && errno == E2BIG)		return false;	if (fd >= 0)		close(fd); 	return true;}