Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <sched.h>
#include "util.h" // for sched_getcpu()
#include "../perf-sys.h"
#include "cloexec.h"
#include "event.h"
#include "asm/bug.h"
#include "debug.h"
#include <unistd.h>
#include <sys/syscall.h>
#include <linux/string.h>
 
static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
 
int __weak sched_getcpu(void)
{
#ifdef __NR_getcpu
<------>unsigned cpu;
<------>int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
<------>if (!err)
<------><------>return cpu;
#else
<------>errno = ENOSYS;
#endif
<------>return -1;
}
 
static int perf_flag_probe(void)
{
<------>/* use 'safest' configuration as used in evsel__fallback() */
<------>struct perf_event_attr attr = {
<------><------>.type = PERF_TYPE_SOFTWARE,
<------><------>.config = PERF_COUNT_SW_CPU_CLOCK,
<------><------>.exclude_kernel = 1,
<------>};
<------>int fd;
<------>int err;
<------>int cpu;
<------>pid_t pid = -1;
<------>char sbuf[STRERR_BUFSIZE];
 
<------>cpu = sched_getcpu();
<------>if (cpu < 0)
<------><------>cpu = 0;
 
<------>/*
<------> * Using -1 for the pid is a workaround to avoid gratuitous jump label
<------> * changes.
<------> */
<------>while (1) {
<------><------>/* check cloexec flag */
<------><------>fd = sys_perf_event_open(&attr, pid, cpu, -1,
<------><------><------><------><------> PERF_FLAG_FD_CLOEXEC);
<------><------>if (fd < 0 && pid == -1 && errno == EACCES) {
<------><------><------>pid = 0;
<------><------><------>continue;
<------><------>}
<------><------>break;
<------>}
<------>err = errno;
 
<------>if (fd >= 0) {
<------><------>close(fd);
<------><------>return 1;
<------>}
 
<------>WARN_ONCE(err != EINVAL && err != EBUSY && err != EACCES,
<------><------>  "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
<------><------>  err, str_error_r(err, sbuf, sizeof(sbuf)));
 
<------>/* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
<------>while (1) {
<------><------>fd = sys_perf_event_open(&attr, pid, cpu, -1, 0);
<------><------>if (fd < 0 && pid == -1 && errno == EACCES) {
<------><------><------>pid = 0;
<------><------><------>continue;
<------><------>}
<------><------>break;
<------>}
<------>err = errno;
 
<------>if (fd >= 0)
<------><------>close(fd);
 
<------>if (WARN_ONCE(fd < 0 && err != EBUSY && err != EACCES,
<------><------>      "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
<------><------>      err, str_error_r(err, sbuf, sizeof(sbuf))))
<------><------>return -1;
 
<------>return 0;
}
 
unsigned long perf_event_open_cloexec_flag(void)
{
<------>static bool probed;
 
<------>if (!probed) {
<------><------>if (perf_flag_probe() <= 0)
<------><------><------>flag = 0;
<------><------>probed = true;
<------>}
 
<------>return flag;
}