1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2022 FUJITSU LIMITED. All rights reserved.
4 * Author: Yang Xu <[email protected]>
5 */
6
7 /*\
8 * [Description]
9 *
10 * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC.
11 *
12 * Set the state of the flag determining whether the timestamp counter can
13 * be read by the process.
14 *
15 * - Pass PR_TSC_ENABLE to arg2 to allow it to be read.
16 * - Pass PR_TSC_SIGSEGV to arg2 to generate a SIGSEGV when read.
17 */
18
19 #include <sys/prctl.h>
20 #include <string.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include "tst_test.h"
24 #include "lapi/prctl.h"
25
26 #define TCASE_ENTRY(tsc_read_stat) { .name = #tsc_read_stat, .read_stat = tsc_read_stat}
27
28 static const char * const tsc_read_stat_names[] = {
29 [0] = "[not set]",
30 [PR_TSC_ENABLE] = "PR_TSC_ENABLE",
31 [PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV",
32 };
33
34 static struct tcase {
35 char *name;
36 int read_stat;
37 } tcases[] = {
38 TCASE_ENTRY(PR_TSC_ENABLE),
39 TCASE_ENTRY(PR_TSC_SIGSEGV)
40 };
41
rdtsc(void)42 static uint64_t rdtsc(void)
43 {
44 uint32_t lo = 0, hi = 0;
45
46 #if (defined(__x86_64__) || defined(__i386__))
47 /* We cannot use "=A", since this would use %rax on x86_64 */
48 __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
49 #endif
50
51 return (uint64_t)hi << 32 | lo;
52 }
53
54
expected_status(int status,int exp_status)55 static int expected_status(int status, int exp_status)
56 {
57 if (!exp_status && WIFEXITED(status))
58 return 0;
59
60 if (exp_status && WIFSIGNALED(status) && WTERMSIG(status) == exp_status)
61 return 0;
62
63 return 1;
64 }
65
verify_prctl(unsigned int n)66 static void verify_prctl(unsigned int n)
67 {
68 struct tcase *tc = &tcases[n];
69 unsigned long long time1, time2;
70 int tsc_val = 0, pid, status;
71
72 pid = SAFE_FORK();
73 if (!pid) {
74 TST_EXP_PASS_SILENT(prctl(PR_SET_TSC, tc->read_stat));
75 TST_EXP_PASS_SILENT(prctl(PR_GET_TSC, &tsc_val));
76 if (tsc_val == tc->read_stat)
77 tst_res(TPASS, "current state is %s(%d)",
78 tc->name, tc->read_stat);
79 else
80 tst_res(TFAIL, "current state is %s(%d), expect %s(%d)",
81 tsc_read_stat_names[tsc_val],
82 tsc_val, tc->name, tc->read_stat);
83
84 time1 = rdtsc();
85 time2 = rdtsc();
86 if (time2 > time1)
87 tst_res(TPASS, "rdtsc works correctly, %lld ->%lld",
88 time1, time2);
89 else
90 tst_res(TFAIL, "rdtsc works incorrectly, %lld ->%lld",
91 time1, time2);
92 exit(0);
93 }
94 SAFE_WAITPID(pid, &status, 0);
95
96 if (expected_status(status, tc->read_stat == PR_TSC_SIGSEGV ? SIGSEGV : 0))
97 tst_res(TFAIL, "Test %s failed", tc->name);
98 else
99 tst_res(TPASS, "Test %s succeeded", tc->name);
100 }
101
102 static struct tst_test test = {
103 .forks_child = 1,
104 .test = verify_prctl,
105 .tcnt = ARRAY_SIZE(tcases),
106 .supported_archs = (const char *const []) {
107 "x86",
108 "x86_64",
109 NULL
110 },
111 };
112