tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
29int nerrs = 0;
30
31#ifdef __x86_64__
32# define VSYS(x) (x)
33#else
34# define VSYS(x) 0
35#endif
36
37typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
38
39const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);
40getcpu_t vdso_getcpu;
41
42void 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
59static long sys_getcpu(unsigned * cpu, unsigned * node,
60 void* cache)
61{
62 return syscall(__NR_getcpu, cpu, node, cache);
63}
64
65static 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
117int main(int argc, char **argv)
118{
119 fill_function_pointers();
120
121 test_getcpu();
122
123 return nerrs ? 1 : 0;
124}