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/*
* Copyright 2014, Michael Ellerman, IBM Corp.
* Licensed under GPLv2.
*/
#define _GNU_SOURCE /* For CPU_ZERO etc. */
#include <errno.h>
#include <sched.h>
#include <setjmp.h>
#include <stdlib.h>
#include <sys/wait.h>
#include "utils.h"
#include "lib.h"
int pick_online_cpu(void)
{
cpu_set_t mask;
int cpu;
CPU_ZERO(&mask);
if (sched_getaffinity(0, sizeof(mask), &mask)) {
perror("sched_getaffinity");
return -1;
}
/* We prefer a primary thread, but skip 0 */
for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)
if (CPU_ISSET(cpu, &mask))
return cpu;
/* Search for anything, but in reverse */
for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)
if (CPU_ISSET(cpu, &mask))
return cpu;
printf("No cpus in affinity mask?!\n");
return -1;
}
int bind_to_cpu(int cpu)
{
cpu_set_t mask;
printf("Binding to cpu %d\n", cpu);
CPU_ZERO(&mask);
CPU_SET(cpu, &mask);
return sched_setaffinity(0, sizeof(mask), &mask);
}
#define PARENT_TOKEN 0xAA
#define CHILD_TOKEN 0x55
int sync_with_child(union pipe read_pipe, union pipe write_pipe)
{
char c = PARENT_TOKEN;
FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
if (c != CHILD_TOKEN) /* sometimes expected */
return 1;
return 0;
}
int wait_for_parent(union pipe read_pipe)
{
char c;
FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
FAIL_IF(c != PARENT_TOKEN);
return 0;
}
int notify_parent(union pipe write_pipe)
{
char c = CHILD_TOKEN;
FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
return 0;
}
int notify_parent_of_error(union pipe write_pipe)
{
char c = ~CHILD_TOKEN;
FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
return 0;
}
int wait_for_child(pid_t child_pid)
{
int rc;
if (waitpid(child_pid, &rc, 0) == -1) {
perror("waitpid");
return 1;
}
if (WIFEXITED(rc))
rc = WEXITSTATUS(rc);
else
rc = 1; /* Signal or other */
return rc;
}
int kill_child_and_wait(pid_t child_pid)
{
kill(child_pid, SIGTERM);
return wait_for_child(child_pid);
}
static int eat_cpu_child(union pipe read_pipe, union pipe write_pipe)
{
volatile int i = 0;
/*
* We are just here to eat cpu and die. So make sure we can be killed,
* and also don't do any custom SIGTERM handling.
*/
signal(SIGTERM, SIG_DFL);
notify_parent(write_pipe);
wait_for_parent(read_pipe);
/* Soak up cpu forever */
while (1) i++;
return 0;
}
pid_t eat_cpu(int (test_function)(void))
{
union pipe read_pipe, write_pipe;
int cpu, rc;
pid_t pid;
cpu = pick_online_cpu();
FAIL_IF(cpu < 0);
FAIL_IF(bind_to_cpu(cpu));
if (pipe(read_pipe.fds) == -1)
return -1;
if (pipe(write_pipe.fds) == -1)
return -1;
pid = fork();
if (pid == 0)
exit(eat_cpu_child(write_pipe, read_pipe));
if (sync_with_child(read_pipe, write_pipe)) {
rc = -1;
goto out;
}
printf("main test running as pid %d\n", getpid());
rc = test_function();
out:
kill(pid, SIGKILL);
return rc;
}
struct addr_range libc, vdso;
int parse_proc_maps(void)
{
unsigned long start, end;
char execute, name[128];
FILE *f;
int rc;
f = fopen("/proc/self/maps", "r");
if (!f) {
perror("fopen");
return -1;
}
do {
/* This skips line with no executable which is what we want */
rc = fscanf(f, "%lx-%lx %*c%*c%c%*c %*x %*d:%*d %*d %127s\n",
&start, &end, &execute, name);
if (rc <= 0)
break;
if (execute != 'x')
continue;
if (strstr(name, "libc")) {
libc.first = start;
libc.last = end - 1;
} else if (strstr(name, "[vdso]")) {
vdso.first = start;
vdso.last = end - 1;
}
} while(1);
fclose(f);
return 0;
}
#define PARANOID_PATH "/proc/sys/kernel/perf_event_paranoid"
bool require_paranoia_below(int level)
{
unsigned long current;
char *end, buf[16];
FILE *f;
int rc;
rc = -1;
f = fopen(PARANOID_PATH, "r");
if (!f) {
perror("fopen");
goto out;
}
if (!fgets(buf, sizeof(buf), f)) {
printf("Couldn't read " PARANOID_PATH "?\n");
goto out_close;
}
current = strtoul(buf, &end, 10);
if (end == buf) {
printf("Couldn't parse " PARANOID_PATH "?\n");
goto out_close;
}
if (current >= level)
goto out;
rc = 0;
out_close:
fclose(f);
out:
return rc;
}
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