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// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/perf_event.h>
#include <stddef.h>
#include <sched.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/wait.h>
#include <unistd.h>
#include "../kselftest_harness.h"
#define __maybe_unused __attribute__((__unused__))
static int sigio_count;
static void handle_sigio(int signum __maybe_unused,
siginfo_t *oh __maybe_unused,
void *uc __maybe_unused)
{
++sigio_count;
}
static void do_child(void)
{
raise(SIGSTOP);
for (int i = 0; i < 20; ++i)
sleep(1);
raise(SIGSTOP);
exit(0);
}
TEST(watermark_signal)
{
struct perf_event_attr attr;
struct perf_event_mmap_page *p = NULL;
struct sigaction previous_sigio, sigio = { 0 };
pid_t child = -1;
int child_status;
int fd = -1;
long page_size = sysconf(_SC_PAGE_SIZE);
sigio.sa_sigaction = handle_sigio;
EXPECT_EQ(sigaction(SIGIO, &sigio, &previous_sigio), 0);
memset(&attr, 0, sizeof(attr));
attr.size = sizeof(attr);
attr.type = PERF_TYPE_SOFTWARE;
attr.config = PERF_COUNT_SW_DUMMY;
attr.sample_period = 1;
attr.disabled = 1;
attr.watermark = 1;
attr.context_switch = 1;
attr.wakeup_watermark = 1;
child = fork();
EXPECT_GE(child, 0);
if (child == 0)
do_child();
else if (child < 0) {
perror("fork()");
goto cleanup;
}
if (waitpid(child, &child_status, WSTOPPED) != child ||
!(WIFSTOPPED(child_status) && WSTOPSIG(child_status) == SIGSTOP)) {
fprintf(stderr,
"failed to sycnhronize with child errno=%d status=%x\n",
errno,
child_status);
goto cleanup;
}
fd = syscall(__NR_perf_event_open, &attr, child, -1, -1,
PERF_FLAG_FD_CLOEXEC);
if (fd < 0) {
fprintf(stderr, "failed opening event %llx\n", attr.config);
goto cleanup;
}
if (fcntl(fd, F_SETFL, FASYNC)) {
perror("F_SETFL FASYNC");
goto cleanup;
}
if (fcntl(fd, F_SETOWN, getpid())) {
perror("F_SETOWN getpid()");
goto cleanup;
}
if (fcntl(fd, F_SETSIG, SIGIO)) {
perror("F_SETSIG SIGIO");
goto cleanup;
}
p = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (p == NULL) {
perror("mmap");
goto cleanup;
}
if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0)) {
perror("PERF_EVENT_IOC_ENABLE");
goto cleanup;
}
if (kill(child, SIGCONT) < 0) {
perror("SIGCONT");
goto cleanup;
}
if (waitpid(child, &child_status, WSTOPPED) != -1 || errno != EINTR)
fprintf(stderr,
"expected SIGIO to terminate wait errno=%d status=%x\n%d",
errno,
child_status,
sigio_count);
EXPECT_GE(sigio_count, 1);
cleanup:
if (p != NULL)
munmap(p, 2 * page_size);
if (fd >= 0)
close(fd);
if (child > 0) {
kill(child, SIGKILL);
waitpid(child, NULL, 0);
}
sigaction(SIGIO, &previous_sigio, NULL);
}
TEST_HARNESS_MAIN
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