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