1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * POWER Data Stream Control Register (DSCR) sysfs thread test
4 *
5 * This test updates the system wide DSCR default value through
6 * sysfs interface which should then update all the CPU specific
7 * DSCR default values which must also be then visible to threads
8 * executing on individual CPUs on the system.
9 *
10 * Copyright 2015, Anshuman Khandual, IBM Corporation.
11 */
12#define _GNU_SOURCE
13#include "dscr.h"
14
15static int test_thread_dscr(unsigned long val)
16{
17 unsigned long cur_dscr, cur_dscr_usr;
18
19 cur_dscr = get_dscr();
20 cur_dscr_usr = get_dscr_usr();
21
22 if (val != cur_dscr) {
23 printf("[cpu %d] Kernel DSCR should be %ld but is %ld\n",
24 sched_getcpu(), val, cur_dscr);
25 return 1;
26 }
27
28 if (val != cur_dscr_usr) {
29 printf("[cpu %d] User DSCR should be %ld but is %ld\n",
30 sched_getcpu(), val, cur_dscr_usr);
31 return 1;
32 }
33 return 0;
34}
35
36static int check_cpu_dscr_thread(unsigned long val)
37{
38 cpu_set_t mask;
39 int cpu;
40
41 for (cpu = 0; cpu < CPU_SETSIZE; cpu++) {
42 CPU_ZERO(&mask);
43 CPU_SET(cpu, &mask);
44 if (sched_setaffinity(0, sizeof(mask), &mask))
45 continue;
46
47 if (test_thread_dscr(val))
48 return 1;
49 }
50 return 0;
51
52}
53
54int dscr_sysfs_thread(void)
55{
56 unsigned long orig_dscr_default;
57 int i, j;
58
59 SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
60
61 orig_dscr_default = get_default_dscr();
62 for (i = 0; i < COUNT; i++) {
63 for (j = 0; j < DSCR_MAX; j++) {
64 set_default_dscr(j);
65 if (check_cpu_dscr_thread(val: j))
66 goto fail;
67 }
68 }
69 set_default_dscr(orig_dscr_default);
70 return 0;
71fail:
72 set_default_dscr(orig_dscr_default);
73 return 1;
74}
75
76int main(int argc, char *argv[])
77{
78 return test_harness(dscr_sysfs_thread, "dscr_sysfs_thread_test");
79}
80

source code of linux/tools/testing/selftests/powerpc/dscr/dscr_sysfs_thread_test.c