aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c96
-rw-r--r--Documentation/prctl/disable-tsc-on-off-stress-test.c95
-rw-r--r--Documentation/prctl/disable-tsc-test.c94
3 files changed, 285 insertions, 0 deletions
diff --git a/Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c b/Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c
new file mode 100644
index 000000000000..f8e8e95e81fd
--- /dev/null
+++ b/Documentation/prctl/disable-tsc-ctxt-sw-stress-test.c
@@ -0,0 +1,96 @@
1/*
2 * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
3 *
4 * Tests if the control register is updated correctly
5 * at context switches
6 *
7 * Warning: this test will cause a very high load for a few seconds
8 *
9 */
10
11#include <stdio.h>
12#include <stdlib.h>
13#include <unistd.h>
14#include <signal.h>
15#include <inttypes.h>
16#include <wait.h>
17
18
19#include <sys/prctl.h>
20#include <linux/prctl.h>
21
22/* Get/set the process' ability to use the timestamp counter instruction */
23#ifndef PR_GET_TSC
24#define PR_GET_TSC 25
25#define PR_SET_TSC 26
26# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */
27# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */
28#endif
29
30uint64_t rdtsc() {
31uint32_t lo, hi;
32/* We cannot use "=A", since this would use %rax on x86_64 */
33__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
34return (uint64_t)hi << 32 | lo;
35}
36
37void sigsegv_expect(int sig)
38{
39 /* */
40}
41
42void segvtask(void)
43{
44 if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0)
45 {
46 perror("prctl");
47 exit(0);
48 }
49 signal(SIGSEGV, sigsegv_expect);
50 alarm(10);
51 rdtsc();
52 fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n");
53 exit(0);
54}
55
56
57void sigsegv_fail(int sig)
58{
59 fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n");
60 exit(0);
61}
62
63void rdtsctask(void)
64{
65 if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0)
66 {
67 perror("prctl");
68 exit(0);
69 }
70 signal(SIGSEGV, sigsegv_fail);
71 alarm(10);
72 for(;;) rdtsc();
73}
74
75
76int main(int argc, char **argv)
77{
78 int n_tasks = 100, i;
79
80 fprintf(stderr, "[No further output means we're allright]\n");
81
82 for (i=0; i<n_tasks; i++)
83 if (fork() == 0)
84 {
85 if (i & 1)
86 segvtask();
87 else
88 rdtsctask();
89 }
90
91 for (i=0; i<n_tasks; i++)
92 wait(NULL);
93
94 exit(0);
95}
96
diff --git a/Documentation/prctl/disable-tsc-on-off-stress-test.c b/Documentation/prctl/disable-tsc-on-off-stress-test.c
new file mode 100644
index 000000000000..1fcd91445375
--- /dev/null
+++ b/Documentation/prctl/disable-tsc-on-off-stress-test.c
@@ -0,0 +1,95 @@
1/*
2 * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
3 *
4 * Tests if the control register is updated correctly
5 * when set with prctl()
6 *
7 * Warning: this test will cause a very high load for a few seconds
8 *
9 */
10
11#include <stdio.h>
12#include <stdlib.h>
13#include <unistd.h>
14#include <signal.h>
15#include <inttypes.h>
16#include <wait.h>
17
18
19#include <sys/prctl.h>
20#include <linux/prctl.h>
21
22/* Get/set the process' ability to use the timestamp counter instruction */
23#ifndef PR_GET_TSC
24#define PR_GET_TSC 25
25#define PR_SET_TSC 26
26# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */
27# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */
28#endif
29
30/* snippet from wikipedia :-) */
31
32uint64_t rdtsc() {
33uint32_t lo, hi;
34/* We cannot use "=A", since this would use %rax on x86_64 */
35__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
36return (uint64_t)hi << 32 | lo;
37}
38
39int should_segv = 0;
40
41void sigsegv_cb(int sig)
42{
43 if (!should_segv)
44 {
45 fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n");
46 exit(0);
47 }
48 if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0)
49 {
50 perror("prctl");
51 exit(0);
52 }
53 should_segv = 0;
54
55 rdtsc();
56}
57
58void task(void)
59{
60 signal(SIGSEGV, sigsegv_cb);
61 alarm(10);
62 for(;;)
63 {
64 rdtsc();
65 if (should_segv)
66 {
67 fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n");
68 exit(0);
69 }
70 if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0)
71 {
72 perror("prctl");
73 exit(0);
74 }
75 should_segv = 1;
76 }
77}
78
79
80int main(int argc, char **argv)
81{
82 int n_tasks = 100, i;
83
84 fprintf(stderr, "[No further output means we're allright]\n");
85
86 for (i=0; i<n_tasks; i++)
87 if (fork() == 0)
88 task();
89
90 for (i=0; i<n_tasks; i++)
91 wait(NULL);
92
93 exit(0);
94}
95
diff --git a/Documentation/prctl/disable-tsc-test.c b/Documentation/prctl/disable-tsc-test.c
new file mode 100644
index 000000000000..843c81eac235
--- /dev/null
+++ b/Documentation/prctl/disable-tsc-test.c
@@ -0,0 +1,94 @@
1/*
2 * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
3 *
4 * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC
5 */
6
7#include <stdio.h>
8#include <stdlib.h>
9#include <unistd.h>
10#include <signal.h>
11#include <inttypes.h>
12
13
14#include <sys/prctl.h>
15#include <linux/prctl.h>
16
17/* Get/set the process' ability to use the timestamp counter instruction */
18#ifndef PR_GET_TSC
19#define PR_GET_TSC 25
20#define PR_SET_TSC 26
21# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */
22# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */
23#endif
24
25const char *tsc_names[] =
26{
27 [0] = "[not set]",
28 [PR_TSC_ENABLE] = "PR_TSC_ENABLE",
29 [PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV",
30};
31
32uint64_t rdtsc() {
33uint32_t lo, hi;
34/* We cannot use "=A", since this would use %rax on x86_64 */
35__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
36return (uint64_t)hi << 32 | lo;
37}
38
39void sigsegv_cb(int sig)
40{
41 int tsc_val = 0;
42
43 printf("[ SIG_SEGV ]\n");
44 printf("prctl(PR_GET_TSC, &tsc_val); ");
45 fflush(stdout);
46
47 if ( prctl(PR_GET_TSC, &tsc_val) == -1)
48 perror("prctl");
49
50 printf("tsc_val == %s\n", tsc_names[tsc_val]);
51 printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
52 fflush(stdout);
53 if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
54 perror("prctl");
55
56 printf("rdtsc() == ");
57}
58
59int main(int argc, char **argv)
60{
61 int tsc_val = 0;
62
63 signal(SIGSEGV, sigsegv_cb);
64
65 printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
66 printf("prctl(PR_GET_TSC, &tsc_val); ");
67 fflush(stdout);
68
69 if ( prctl(PR_GET_TSC, &tsc_val) == -1)
70 perror("prctl");
71
72 printf("tsc_val == %s\n", tsc_names[tsc_val]);
73 printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
74 printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
75 fflush(stdout);
76
77 if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
78 perror("prctl");
79
80 printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
81 printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n");
82 fflush(stdout);
83
84 if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1)
85 perror("prctl");
86
87 printf("rdtsc() == ");
88 fflush(stdout);
89 printf("%llu\n", (unsigned long long)rdtsc());
90 fflush(stdout);
91
92 exit(EXIT_SUCCESS);
93}
94
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-01 01:26:37 -0400