tools/testing/selftests/x86/test_vdso.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * ldt_gdt.c - Test cases for LDT and GDT access
   4  * Copyright (c) 2011-2015 Andrew Lutomirski
   5  */
   6
   7 #define _GNU_SOURCE
   8
   9 #include <stdio.h>
  10 #include <sys/time.h>
  11 #include <time.h>
  12 #include <stdlib.h>
  13 #include <unistd.h>
  14 #include <sys/syscall.h>
  15 #include <dlfcn.h>
  16 #include <string.h>
  17 #include <errno.h>
  18 #include <sched.h>
  19 #include <stdbool.h>
  20
  21 #ifndef SYS_getcpu
  22 # ifdef __x86_64__
  23 #  define SYS_getcpu 309
  24 # else
  25 #  define SYS_getcpu 318
  26 # endif
  27 #endif
  28
  29 int nerrs = 0;
  30
  31 #ifdef __x86_64__
  32 # define VSYS(x) (x)
  33 #else
  34 # define VSYS(x) 0
  35 #endif
  36
  37 typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
  38
  39 const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);
  40 getcpu_t vdso_getcpu;
  41
  42 void fill_function_pointers()
  43 {
  44         void *vdso = dlopen("linux-vdso.so.1",
  45                             RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  46         if (!vdso)
  47                 vdso = dlopen("linux-gate.so.1",
  48                               RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
  49         if (!vdso) {
  50                 printf("[WARN]\tfailed to find vDSO\n");
  51                 return;
  52         }
  53
  54         vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");
  55         if (!vdso_getcpu)
  56                 printf("Warning: failed to find getcpu in vDSO\n");
  57 }
  58
  59 static long sys_getcpu(unsigned * cpu, unsigned * node,
  60                        void* cache)
  61 {
  62         return syscall(__NR_getcpu, cpu, node, cache);
  63 }
  64
  65 static void test_getcpu(void)
  66 {
  67         printf("[RUN]\tTesting getcpu...\n");
  68
  69         for (int cpu = 0; ; cpu++) {
  70                 cpu_set_t cpuset;
  71                 CPU_ZERO(&cpuset);
  72                 CPU_SET(cpu, &cpuset);
  73                 if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
  74                         return;
  75
  76                 unsigned cpu_sys, cpu_vdso, cpu_vsys,
  77                         node_sys, node_vdso, node_vsys;
  78                 long ret_sys, ret_vdso = 1, ret_vsys = 1;
  79                 unsigned node;
  80
  81                 ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
  82                 if (vdso_getcpu)
  83                         ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
  84                 if (vgetcpu)
  85                         ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
  86
  87                 if (!ret_sys)
  88                         node = node_sys;
  89                 else if (!ret_vdso)
  90                         node = node_vdso;
  91                 else if (!ret_vsys)
  92                         node = node_vsys;
  93
  94                 bool ok = true;
  95                 if (!ret_sys && (cpu_sys != cpu || node_sys != node))
  96                         ok = false;
  97                 if (!ret_vdso && (cpu_vdso != cpu || node_vdso != node))
  98                         ok = false;
  99                 if (!ret_vsys && (cpu_vsys != cpu || node_vsys != node))
 100                         ok = false;
 101
 102                 printf("[%s]\tCPU %u:", ok ? "OK" : "FAIL", cpu);
 103                 if (!ret_sys)
 104                         printf(" syscall: cpu %u, node %u", cpu_sys, node_sys);
 105                 if (!ret_vdso)
 106                         printf(" vdso: cpu %u, node %u", cpu_vdso, node_vdso);
 107                 if (!ret_vsys)
 108                         printf(" vsyscall: cpu %u, node %u", cpu_vsys,
 109                                node_vsys);
 110                 printf("\n");
 111
 112                 if (!ok)
 113                         nerrs++;
 114         }
 115 }
 116
 117 int main(int argc, char **argv)
 118 {
 119         fill_function_pointers();
 120
 121         test_getcpu();
 122
 123         return nerrs ? 1 : 0;
 124 }