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// SPDX-License-Identifier: GPL-2.0
/*
* ldt_gdt.c - Test cases for LDT and GDT access
* Copyright (c) 2011-2015 Andrew Lutomirski
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <dlfcn.h>
#include <string.h>
#include <errno.h>
#include <sched.h>
#include <stdbool.h>
#ifndef SYS_getcpu
# ifdef __x86_64__
# define SYS_getcpu 309
# else
# define SYS_getcpu 318
# endif
#endif
/* max length of lines in /proc/self/maps - anything longer is skipped here */
#define MAPS_LINE_LEN 128
int nerrs = 0;
typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
getcpu_t vgetcpu;
getcpu_t vdso_getcpu;
static void *vsyscall_getcpu(void)
{
#ifdef __x86_64__
FILE *maps;
char line[MAPS_LINE_LEN];
bool found = false;
maps = fopen("/proc/self/maps", "r");
if (!maps) /* might still be present, but ignore it here, as we test vDSO not vsyscall */
return NULL;
while (fgets(line, MAPS_LINE_LEN, maps)) {
char r, x;
void *start, *end;
char name[MAPS_LINE_LEN];
/* sscanf() is safe here as strlen(name) >= strlen(line) */
if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
&start, &end, &r, &x, name) != 5)
continue;
if (strcmp(name, "[vsyscall]"))
continue;
/* assume entries are OK, as we test vDSO here not vsyscall */
found = true;
break;
}
fclose(maps);
if (!found) {
printf("Warning: failed to find vsyscall getcpu\n");
return NULL;
}
return (void *) (0xffffffffff600800);
#else
return NULL;
#endif
}
static void fill_function_pointers()
{
void *vdso = dlopen("linux-vdso.so.1",
RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
if (!vdso)
vdso = dlopen("linux-gate.so.1",
RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
if (!vdso) {
printf("[WARN]\tfailed to find vDSO\n");
return;
}
vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");
if (!vdso_getcpu)
printf("Warning: failed to find getcpu in vDSO\n");
vgetcpu = (getcpu_t) vsyscall_getcpu();
}
static long sys_getcpu(unsigned * cpu, unsigned * node,
void* cache)
{
return syscall(__NR_getcpu, cpu, node, cache);
}
static void test_getcpu(void)
{
printf("[RUN]\tTesting getcpu...\n");
for (int cpu = 0; ; cpu++) {
cpu_set_t cpuset;
CPU_ZERO(&cpuset);
CPU_SET(cpu, &cpuset);
if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
return;
unsigned cpu_sys, cpu_vdso, cpu_vsys,
node_sys, node_vdso, node_vsys;
long ret_sys, ret_vdso = 1, ret_vsys = 1;
unsigned node;
ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
if (vdso_getcpu)
ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
if (vgetcpu)
ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
if (!ret_sys)
node = node_sys;
else if (!ret_vdso)
node = node_vdso;
else if (!ret_vsys)
node = node_vsys;
bool ok = true;
if (!ret_sys && (cpu_sys != cpu || node_sys != node))
ok = false;
if (!ret_vdso && (cpu_vdso != cpu || node_vdso != node))
ok = false;
if (!ret_vsys && (cpu_vsys != cpu || node_vsys != node))
ok = false;
printf("[%s]\tCPU %u:", ok ? "OK" : "FAIL", cpu);
if (!ret_sys)
printf(" syscall: cpu %u, node %u", cpu_sys, node_sys);
if (!ret_vdso)
printf(" vdso: cpu %u, node %u", cpu_vdso, node_vdso);
if (!ret_vsys)
printf(" vsyscall: cpu %u, node %u", cpu_vsys,
node_vsys);
printf("\n");
if (!ok)
nerrs++;
}
}
int main(int argc, char **argv)
{
fill_function_pointers();
test_getcpu();
return nerrs ? 1 : 0;
}
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